Abstract:
A clinical decision support application screens drug orders for drug dosing errors based on patient-specific information. The support application verifies that medication dosages are appropriately adjusted for renal function based upon calculated creatinine clearance (CrCI). In addition to looking for overdosing errors, other important features are its ability to detect under-dosing, and dosages and intervals that are not consistent with institution policy. The clinical decision support application also detects potentially dangerous drug combinations and serves as a safety net by providing a drug-drug interaction alert to a healthcare professional as well as reminders and escalations. Alert reports contain patient demographic data, the dose and start date of the interacting medications, pertinent laboratory or drug data, an educational comment with a recommendation for alternative therapy, and a customized outcome section that includes expected adverse events and treatment options for the detected interaction.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention relates to computer-implemented expert systems and, in particular, to a computer system for monitoring drug orders for a medical practice.  
         BACKGROUND OF THE INVENTION  
         [0002]    It is widely known that the primary goal of healthcare organizations is the health and well-being of patients under the care of such an organization. To promote the health and well-being of patients at a competitive cost, healthcare organizations, such as hospitals for example, have become quite large and many clinicians may contribute to the treatment of a particular patient. Each such clinician can prescribe medication to such a patient and such prescriptions without full knowledge of other medications administered to the patient are increasingly common.  
           [0003]    As a result, inappropriate medication administration in such healthcare organizations is a serious problem. Improperly administered medications can cost the patient their comfort, their health, and even their lives. Accordingly, proper medication administration is an extremely important matter for such healthcare organizations. Any system which improves medication administration has significant value to such healthcare organizations.  
         SUMMARY OF THE INVENTION  
         [0004]    In accordance with the present invention, drug orders and laboratory results for patients of a healthcare organization such as a hospital are automatically monitored and analyzed for dosing errors and drug-drug interactions. The monitoring is accomplished by using triggers on one or more databases which store patient records and drug orders for the healthcare organization. The use of triggers enables such monitoring and analysis to be accomplished without requiring physicians to enter data specific to a particular patient and/or drug order or otherwise increasing the workload of physicians. Instead, updates and additions to the databases already used for treating patients automatically initiate analysis of such updated information for dosing errors and drug-drug interactions.  
           [0005]    Dosage monitoring verifies that drug doses are appropriately adjusted for renal function based upon calculated creatinine clearance. Overdosing, under-dosing, and dosages and intervals or frequencies that are not consistent with policies of the healthcare organization are detected.  
           [0006]    Analysis of drug orders and laboratory results for dosing errors includes application of predetermined rules for allowable doses. Each rule specifies a range of patient weights and creatinine clearances for which the rule is applicable. Each rule can further specify one or more allowable dose amounts and one or more allowable dose frequencies. The dose amounts can be specified as absolute amounts, amount per unit of the patient&#39;s actual weight, or amount per unit of the patient&#39;s dosage weight calculated from the patient&#39;s weight and serum creatinine levels represented in laboratory results. Allowable dosing can also be specified in terms of predicted peak and trough blood levels of the drug as estimated from the dose amount and frequency and the patient&#39;s calculated creatinine clearance and ideal body weight. Rules can also specify allowable rounding values of drug orders. For example, a rule can specify that a particular drug is to be given in doses of integer multiples of 500 mg.  
           [0007]    If a particular drug order does not comport with the predetermined rules for allowable drug orders, an alert message is directed to a clinician who then reviews the drug order and can override the dosage monitor to indicate the drug order is allowable or can modify the drug order for compliance with the predetermined rules. The alert message indicates the patient and the drug order which violates the allowable rules. In addition, the alert message includes recommendations for the drug of the violating drug order. The recommendations include recommended dosage amounts and frequencies. The dosage amounts of the recommendations, like the dosage amounts of the rules, can be expressed in absolute values or weighted values. If the recommended dosage amount is expressed in weighted values, absolute dosage amount values are calculated from patient data and laboratory result data to provide absolute recommended dosage amounts to the clinician in the alert message.  
           [0008]    In one implementation of dosage monitoring according to the present invention, physicians agreed with recommended dosage changes 75% of the time. Approximately 3% of all drug orders so monitored are changed as a result of alert messages. Even though dosage monitoring is performed without direct interaction by the prescribing physician, prescription appropriateness is improved as evidenced by a 50% reduction in the rate of drug orders resulting in alert messages.  
           [0009]    Drug-drug interactions are detected by monitoring and analyzing new and updated drug orders and laboratory results for patients of the healthcare organization. For example, a new drug order for a particular patient triggers analysis of all drug orders of the patient. An alert is generated if orders for any two interacting drugs are concurrently active, if orders for two interacting drugs are active too close to one another in time, or if an order for a precipitating drug follows too closely after an order for an object drug which is affected by the precipitating drug. Drug interactions, including the drugs that interact with one another and the relative timing required for interaction, are predetermined and stored in a rule database. An alert is similarly generated if a single drug order exceeds a predetermined duration limit.  
           [0010]    A new laboratory result can also indicate a potential adverse drug effect. In particular, new and updated laboratory results are compared to predetermined ranges of acceptable values. If a laboratory result exceeds a corresponding predetermined range of acceptable values, an alert message is sent to a clinician so that the clinician can assess the patient&#39;s situation and determine whether intervention is appropriate.  
           [0011]    Alert messages are sent to a clinician by e-mail. High priority alert messages are sent to the clinician by pager, wireless telephone, fax, and/or printer in an attempt to get the clinician&#39;s immediate attention. High priority alerts pertain to dosing errors and/or drug-drug interactions which are potentially life threatening. In either case, the clinician is required to acknowledge the alert message and enter data describing the resolution of the matter to which the alert message pertains. If the alert message is not acknowledged within a predetermined amount of time, the alert message is sent again. After a predetermined number of times of sending the alert message, the alert message is escalated. Escalation can include sending the message by a different communications channel, e.g., wireless telephone to an on-call physician, and/or by altering the message to draw more attention to itself.  
           [0012]    The particular clinician to which the alert messages are sent is determined according to a scheduled contact database which includes contact information for each day of the week, various times of the day, and various other schedules. Such schedules can also include special schedules for holidays and vacation time for various clinicians. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    [0013]FIG. 1 is a block diagram of a medication supervisor system according to the present invention.  
         [0014]    [0014]FIG. 2 is a block diagram of a drug prescription and patient records database of FIG. 1 in greater detail.  
         [0015]    [0015]FIG. 3 is a block diagram of dosage monitor records of FIG. 2 in greater detail.  
         [0016]    [0016]FIG. 4 is a block diagram of a predetermined drug dosing rule in accordance with the present invention.  
         [0017]    [0017]FIG. 5 is a logic flow diagram of the initialization of database triggers to initial dosing analysis in accordance with the present invention.  
         [0018]    [0018]FIG. 6 is a logic flow diagram of dosage monitoring in accordance with the present invention.  
         [0019]    [0019]FIG. 7 is a logic flow diagram of the determination of whether a particular drug order is allowable in accordance with the present invention.  
         [0020]    [0020]FIG. 8 is a logic flow diagram of the evaluation of a value rule.  
         [0021]    [0021]FIG. 9 is a logic flow diagram of the evaluation of a weighted rule.  
         [0022]    [0022]FIG. 10 is a logic flow diagram of the evaluation of an amino rule.  
         [0023]    [0023]FIG. 11 is a logic flow diagram of the evaluation of a first-value rule.  
         [0024]    [0024]FIG. 12 is a logic flow diagram of the evaluation of a peak and trough rule.  
         [0025]    [0025]FIG. 13 is a logic flow diagram of the determination by the dosage monitor of FIG. 1 of whether peak-and-trough rules indicate that a particular drug order is allowable.  
         [0026]    [0026]FIG. 14 is a logic flow diagram of the preparation of alert message by the dosage monitor of FIG. 1.  
         [0027]    [0027]FIG. 15 is a block diagram of ADE monitor records of FIG. 2 in greater detail.  
         [0028]    [0028]FIG. 16 is a logic flow diagram of ADE monitoring in accordance with the present invention.  
         [0029]    FIGS.  17 - 18  are logic flow diagrams of the analysis of drug orders for drug-drug interactions and drug duration errors.  
         [0030]    [0030]FIG. 19 is a logic flow diagram of the analysis of laboratory results for panic levels.  
         [0031]    [0031]FIG. 20 is a logic flow diagram of the sending of alert messages generated by dosage and ADE monitoring.  
         [0032]    [0032]FIG. 21 is a logic flow diagram of the re-sending and escalation of unacknowledged alert messages.  
         [0033]    FIGS.  22 A-B are example reports illustrating allowable rules and recommendations for dosage monitoring in accordance with the present invention.  
         [0034]    FIGS.  23 - 24  are screen views of alert messages and an acknowledgment interface for ADE monitoring in accordance with the present invention.  
         [0035]    FIGS.  25 - 26  are screen views of alert messages and an acknowledgment interface for dosage monitoring in accordance with the present invention.  
         [0036]    FIGS.  27 - 53  are logic flow diagrams of dosage monitoring in accordance with the present invention.  
         [0037]    FIGS.  54 - 80  are logic flow diagrams of ADE monitoring in accordance with the present invention.  
         [0038]    FIGS.  81 - 95  are logic flow diagrams for delivery of alert messages in accordance with the present invention.  
     
    
     DETAILED DESCRIPTION  
       [0039]    In accordance with the present invention, medication supervisor system  100  (FIG. 1) includes a dosage monitor  102  which monitors proper dosing of drugs administred to patients and an ADE monitor  104  which monitors drug orders for drug-drug interactions. In this illustrative embodiment, dosage monitor  102  and ADE monitor  104  operate without direct involvement by physicians on an ongoing basis such that work by the physicians is unimpaired by operation of dosage monitor  102  and ADE monitor  104 . In particular, physicians treating patients interact with a hospital interface  108 . Hospital interface  108  is a conventional hospital administration system in which clinicians and administrators enter and manage data representing various patients, their locations, their treatment, and their laboratory results. Such data is represented in a drug prescription and patient records database  106  in a conventional manner.  
         [0040]    Similarly, pharmacists who provide drugs to such patients in accordance with prescriptions authored by physicians do so through a pharmacist interface  110 . Pharmacist interface  110  is a conventional interface by which pharmacists manage patients&#39; prescriptions. Such prescriptions are represented by data in drug prescription and patient records database  106  in a conventional manner.  
         [0041]    Dosage monitor  102  and ADE monitor  104  operate without interrupting the conventional work of clinicians and pharmacists by use of a trigger manager  112 . Trigger manager  112  sets triggers in drug prescription and patient records database  106  such that addition and/or modification of drug orders, patient records, and/or laboratory results initiate processing by dosage monitor  102  and ADE monitor  104  in the manner described more completely below. In addition, dosage monitor  102  and ADE monitor  104  use an alert manager  114  to notify one or more clinicians when an inappropriate medication order is detected in a manner described more completely below.  
         [0042]    Drug prescription and patient records database  106  is shown in greater detail in FIG. 2 and includes (i) patient&#39;s records  202 , (ii) laboratory results  204 , (iii) drug orders  206 , (iv) dosage monitor records  208 , and (v) ADE monitor records  210 . Patient&#39;s records  202  include data representing various patients under the care of a particular healthcare organization, including such information as the patient&#39;s name, location, admission date, discharge date, age, gender, height, and weight. Laboratory results  204  include data representing results of laboratory tests performed on such patients. Drug orders  206  include data representing various orders of drugs to be administered to the patients.  
         [0043]    Dosage Monitor  102   
         [0044]    Dosage monitor records  208  is shown in greater detail in FIG. 3. Dosage monitor records  208  include (i) dosage alert candidates  302 , (ii) allowable rules  304 , (iii) recommendations  306 , and (iv) a workspace  308 . Dosage alert candidates  302  includes data representing drug orders to be analyzed by dosage monitor  102  in a manner described in greater detail below. Allowable rules  304  stores data representing rules of allowable drug orders. Such rules are configured by clinicians such that violations of the rules are to be reported. Workspace  308  which is used by dosage monitor  102  (FIG. 1) to analyze dosage alert candidates  302  (FIG. 3).  
         [0045]    Illustrative descriptions of examples of allowable rules and recommendations are shown in FIGS.  22 A-B. FIG. 22A includes an illustrative description of allowable rules and recommendations for Meropenem, and FIG. 22B includes an illustrative description of allowable rules and recommendations for Acyclovir IV according to one illustrative example of the present invention.  
         [0046]    Rule  400  (FIG. 4) is representative of an allowable rule specified in allowable rules  304  (FIG. 3). Rule  400  (FIG. 4) includes a drug identifier  402  which specifies the drug to which rule  400  pertains. In one embodiment, drug identifier is a drug identifier used in Multum databases of Multum Information Services, Inc. of Denver, Colorado. Rule type  404  specifies the type of rule represented by rule  400 . In this illustrative embodiment, a rule can be peak-and-trough, first-value, multiplied, amino, rounding, or value. Each of these rule types are described more completely below.  
         [0047]    CrCl limits  406  and weight limits  408  specify creatinine clearance levels and body weights, respectively, of patients for which rule  400  is applicable. Dose limits  410  specify allowable dosage amounts according to rule  400 . Frequency limits  412  specify allowable dosage frequency according to rule  400 . Round value  414  specifies a dosage increment according to rule  400 . For example, if round value  414  specifies  500  milligrams, an allowable dosage would be an integer multiple of  500  milligrams.  
         [0048]    As described above, allowable rules  304  specify allowable drug orders. If dosage monitor  102  (FIG. 1) detects a violation of allowable rules  304  (FIG. 3), dosage monitor  102  (FIG. 1) alerts a clinician in the manner described below. Recommendations  306  include recommendation rules which are specified in a manner which is analogous to that described above with respect to allowable rules  304  and rule  400 . The specification of allowable rules allows for minor changes in CrCl, whereas the specification for recommendations represents optimal drug therapy. As a result, a drug order which exceeds a recommended drug application by an insignificant amount (i.e., does not exceed an allowable drug application) does not generate an alert.  
         [0049]    For monitoring by both dosage monitor  102  (FIG. 1) and ADE monitor  104 , trigger manager  112  initializes a number of triggers on drug prescription and patient records database  106  as shown in logic flow diagram  500  (FIG. 5). In step  502 , trigger manager  112  (FIG. 1) cleans up ADE alert records. Briefly, deletion of an ADE alert causes deletion of corresponding ADE drug alerts and ADE laboratory result alerts according to the trigger initialized in step  502  (FIG. 5).  
         [0050]    In step  504 , trigger manager  112  (FIG. 1) initializes a trigger in which new and updated orders for drugs in drug orders  206  (FIG. 2) cause corresponding new records in dosage alert candidates  302  (FIG. 3) and ADE alert candidates  1502  (FIG. 15). In step  506  (FIG. 5), trigger manager  112  (FIG. 1) initializes a trigger in which new creatinine clearance measurements cause updates in patient records  202  (FIG. 2). In step  508  (FIG. 5), trigger manager  112  (FIG. 1) initializes a trigger in which new and updated records in patient records  202  cause dosage monitor  102  to analyze drug orders for those new and updated patients. In step  510  (FIG. 5), trigger manager  112  (FIG. 1) initializes a trigger in which new patient records in patient records  202  (FIG. 2) causes new creatinine clearance measurement and calculations for such new patients.  
         [0051]    Thus, dosage monitor  102  (FIG. 1) is invoked by addition or modification of patients records  202  (FIG. 2) and/or addition or modification of drug orders  206 . As described above, the invocation of dosage monitor  102  (FIG. 1) is without any direct interaction by clinicians. Specifically, no clinician is required to identify candidates for dosage monitor  102  and to invoke dosage monitor  102 . Instead, clinicians go about their normal activity and dosage monitor  102  leverages from activity in drug prescription and patient records database  106 , thus producing no additional workload for the clinicians.  
         [0052]    Processing by dosage monitor  102  is shown in logic flow diagram  600  (FIG. 6). In step  602 , dosage monitor  102  collects candidates, e.g., dosage monitor candidates  302  (FIG. 3), for analysis. In step  604  (FIG. 6), dosage monitor  102  (FIG. 1) determines which of dosage monitor candidates  302  (FIG. 3) are to be currently evaluated. In this illustrative embodiment, dosage monitor  102  (FIG. 1) evaluates drug orders which are current, i.e., have begun and have not yet stopped, and drug orders which will begin soon. In addition, evaluation of some drug orders, e.g., drugs orders for Omeprazole and Lansoprazole, by dosage monitor  102  are postponed for a period of time, e.g., 121 hours.  
         [0053]    Loop step  606  and next step  612  define a loop in which each of the drug orders evaluated by dosage monitor  102  is processed according to steps  608 - 610 . During each iteration of the loop of steps  606 - 612 , the particular drug order processed by dosage monitor  102  is sometimes referred to as the subject drug order. For each candidate drug order, processing transfers from loop step  606  to test step  608 . Once all candidate drug orders have been processed according to the loop of steps  606 - 612 , processing according to logic flow diagram  600  completes.  
         [0054]    In test step  608 , dosage monitor  102  (FIG. 1) determines whether the subject drug order satisfies allowable rules  304  (FIG. 3) in the manner described below. If the subject drug order satisfies allowable rules  304 , processing transfers to next step  612  (FIG. 6) and the next drug order is processed according to the loop of steps  606 - 612 . Conversely, if the subject drug order violates allowable rules  304  (FIG. 3), dosage monitor  102  (FIG. 1) alerts a clinician of the violation in step  610  in a manner described more completely below.  
         [0055]    Thus, according to logic flow diagram  600 , dosage monitor  102  (FIG. 1) determines whether drug orders comport with allowable rules  304  in test step  608  and report any violations in step  610 . Test step  608  is shown in greater detail as logic flow diagram  608  (FIG. 7).  
         [0056]    Loop step  702  and next step  706  define a loop in which dosage monitor  102  (FIG. 1) evaluates the subject drug order for each allowable rule corresponding to the drug of the subject drug order in step  704  (FIG. 7). A particular allowable rule applies to a particular drug order if drug identifier  402  (FIG. 4) identifies the subject drug of the drug order. During each iteration of the loop of steps  702 - 706 , the particular allowable rule is sometimes referred to as the subject rule. When all allowable rules applicable to the subject drug order have been evaluated by dosage monitor  102 , processing transfers to test step  708  which is described below.  
         [0057]    There are several types of rules in this illustrative embodiment of the present invention. As described above, a rule can be peak-and-trough, first-value, multiplied, amino, rounding, or value. A value rule is a rule which is not a peak-and-trough, first-value, multiplied, amino, or rounding rule, each of which is described more completely below. Dosage monitor  102  (FIG. 1) evaluates a drug order according to a value rule in step  704  (FIG. 7) in the manner shown in logic flow diagram  800  (FIG. 8).  
         [0058]    In step  802 , dosage monitor  102  (FIG. 1) retrieves the dosage amount and dosage frequency of the subject drug order from dosage alert candidates  302 . In step  804  (FIG. 8), dosage monitor  102  converts the units of the dosage amount if necessary. For example, if the subject drug order specifies a dosage amount in ounces and the subject rule specifies allowable amounts in milligrams, the allowable amounts of the subject rule are converted to ounces and stored in workspace  308 . Similarly, the dosage amount of the subject drug order can be converted to milligrams and represented in workspace  308 . In either case, any difference in units in amount between the subject drug order and the subject rule are resolved in step  804 .  
         [0059]    In test step  806  (FIG. 8), dosage monitor  102  ensures that the weight and creatinine clearance of the patient is sufficiently recent and within limits of applicable weights as specified in weight limits  408  (FIG. 4) and CrCl limits  406  of the subject rule. If no recent serum creatinine result exists and the drug order has been active for more than12 hours, then a normal serum creatinine is assumed for the subject patient. If no recent serum creatinine results exists and the drug order has been active for less than 12 hours, the drug order screening is delayed for 12 hours. If no recent measured weight of the patient is available or if the weight and creatinine clearance of the subject patient are outside the limits specified in fields  406 - 408  of the subject rule, the subject rule is disregarded in step  808  and processed according to logic flow diagram  800 , and therefore step  704  (FIG. 7), completes. Otherwise, if the weight and creatinine clearance of the subject patient are within the limits specified in fields  406 - 408  of the subject rule, processing continues with test step  810 .  
         [0060]    In test step  810  (FIG. 8), dosage monitor  102  (FIG. 1) determines whether the dosage amount of the subject drug order is specified by the subject rule as allowable. Dose limits  410  (FIG. 4) of the subject rule can specify either a range of amounts or one or more specific discrete amounts which are allowable dosages for the drug of the subject drug order. Dosage monitor  102  (FIG. 1) determines whether the dosage amount of the subject drug order is included within the range or included in the one or more discrete amounts specified by the subject rule.  
         [0061]    If the dosage amount of the subject rule is not specified as allowable by the subject rule, processing transfers to step  812  (FIG. 8) in which dosage monitor  102  determines that the subject drug order violates the subject rule and processing according to logic flow diagram  800 , and thus, step  704  (FIG. 7), completes. Conversely, if the dosage amount of the subject rule is specified as allowable by the subject rule, processing transfers to test step  814  (FIG. 8).  
         [0062]    In test step  814 , dosage monitor  102  (FIG. 1) determines whether the dosage frequency of the subject drug order is specified by the subject rule as allowable. Frequency limits  412  (FIG. 4) of the subject rule can specify either a range of frequencies or one or more specific discrete frequencies which are allowable dosage frequencies for the drug of the subject drug order. Dosage monitor  102  (FIG. 1) determines whether the dosage frequency of the subject drug order is included within the range or included in the one or more discrete frequencies specified by the subject rule.  
         [0063]    If the dosage frequency of the subject rule is not specified as allowable by the subject rule, processing transfers to step  816  (FIG. 8) in which dosage monitor  102  determines that the subject drug order violates the subject rule and processing according to logic flow diagram  800 , and thus, step  704  (FIG. 7), completes. Conversely, if the dosage amount of the subject rule is specified as allowable by the subject rule, processing transfers to step  818  (FIG. 8) in which dosage monitor  102  (FIG. 1) determines that the subject drug order satisfies the subject rule and processing according to logic flow diagram  800 , and thus, step  704  (FIG. 7), completes.  
         [0064]    Thus, according to logic flow diagram  800 , dosage monitor  102  compares the dosage amount and dosage frequency of the subject drug order to absolute limits in evaluating a value rule.  
         [0065]    Dosage monitor  102  (FIG. 1) evaluates a drug order according to a multiplied rule in step  704  in the manner shown in logic flow diagram  900  (FIG. 9). In step  902 , dosage monitor  102  (FIG. 1) retrieves the dosage amount and dosage frequency of the subject drug order from dosage alert candidates  302 . In step  904  (FIG. 9), dosage monitor  102  converts the units of the dosage amount if necessary in the manner described above with respect to step  804 .  
         [0066]    In steps  906 - 908 , dosage monitor  102  ensures that the weight and creatinine clearance of the patient is sufficiently recent and within limits of applicable weights as specified in weight limits  408  (FIG. 4) and CrCl limits  406  of the subject rule in the manner described above with respect to steps  806 - 808  (FIG. 8).  
         [0067]    In step  910  (FIG. 9), dosage monitor  102  (FIG. 1) weights the allowable dosage amounts as represented in dosage limits  410  (FIG. 4) of the subject rule by the actual measured weight of the patient of the subject drug order. The resulting weighted dosage amount limits are stored in workspace  308  (FIG. 3) in this illustrative embodiment.  
         [0068]    In test step  912  (FIG. 9), dosage monitor  102  (FIG. 1) determines whether the dosage amount of the subject drug order is specified by the subject rule as allowable. Dosage monitor  102  (FIG. 1) determines whether the dosage amount of the subject drug order is included within the range or included in the one or more discrete amounts specified by the weighted allowable dosage amounts determined in step  910 .  
         [0069]    If the dosage amount of the subject rule is not specified as allowable by the subject rule, processing transfers to step  914  (FIG. 9) in which dosage monitor  102  determines that the subject drug order violates the subject rule and processing according to logic flow diagram  900 , and thus, step  704  (FIG. 7), completes. Conversely, if the dosage amount of the subject rule is specified as allowable by the subject rule, processing transfers to test step  916  (FIG. 9).  
         [0070]    In test step  916 , dosage monitor  102  (FIG. 1) determines whether the dosage frequency of the subject drug order is specified by the subject rule as allowable in the manner described above with respect to test step  814  (FIG. 8).  
         [0071]    If the dosage frequency of the subject rule is not specified as allowable by the subject rule, processing transfers to step  918  (FIG. 9) in which dosage monitor  102  determines that the subject drug order violates the subject rule and processing according to logic flow diagram  900 , and thus, step  704  (FIG. 7), completes. Conversely, if the dosage amount of the subject rule is specified as allowable by the subject rule, processing transfers to step  920  (FIG. 9) in which dosage monitor  102  (FIG. 1) determines that the subject drug order satisfies the subject rule and processing according to logic flow diagram  900 , and thus, step  704  (FIG. 7), completes.  
         [0072]    Thus, according to logic flow diagram  900 , dosage monitor  102  compares the dosage amount and dosage frequency of the subject drug order to limits weighted by the patient&#39;s actual weight in evaluating a multiplied rule.  
         [0073]    Dosage monitor  102  (FIG. 1) evaluates a drug order according to an amino rule in step  704  in the manner shown in logic flow diagram  1000  (FIG. 10). In step  1002 , dosage monitor  102  (FIG. 1) retrieves the dosage amount and dosage frequency of the subject drug order from dosage alert candidates  302 . In step  1004  (FIG. 10), dosage monitor  102  converts the units of the dosage amount and frequency if necessary in the manner described above with respect to step  804 .  
         [0074]    In step  1006  (FIG. 10), dosage monitor  102  (FIG. 1) weights the allowable dosage amounts as represented in dosage limits  410  (FIG. 4) of the subject rule by the calculated dosage weight of the patient of the subject drug order. Dosage monitor  102  (FIG. 1) calculates dosage weight of the patient from the patient&#39;s actual measured weight as represented in patient&#39;s records  202  and from the patient&#39;s serum creatinine as represented in laboratory results  204  according to a well-known equation. In this illustrative embodiment, dosage monitor  102  (FIG. 1) uses any of the following Cockroft-Gault equations to estimate creatinine clearance and to calculate an appropriate dosage weight:  
       MaleCrCl   =         (     140   -   age     )          [       2.3        (     HeightInInches   -   60     )       +   50     ]         Scr   ×   72               FemaleCrCl   =           (     140   -   age     )          [       2.3        (     HeightInInches   -   60     )       +   45.5     ]            (   0.85   )         Scr   ×   72                             
 
         [0075]    If the subject patient&#39;s height is not available or is not between 54 and 87 inches, dosage monitor  102  uses a normalized Cockroft-Gault equation to estimate creatinine clearance: 
         MaleCrCl=140−age  
         FemaleCrCl=(140−age)×0.85  
         [0076]    The resulting weighted dosage amount limits are stored in workspace  308  (FIG. 3) in this illustrative embodiment. Dosage monitor  102  ensures that the measured actual weight of the patient is sufficiently recent before weighting the allowable dosage amounts in step  1006  (FIG. 10). Similarly, dosage monitor  102  ensures that the creatinine clearance levels calculated from measured serum creatinine of the patient are sufficiently recent before weighting the allowable dosage amounts in step  1006  (FIG. 10). If no recent serum creatinine result exists and the drug order has been active for more than 12 hours, then a normal serum creatinine is assumed. If no recent serum creatinine results exists and the drug order has been active for less than 12 hours, the drug order screening is delayed for 12 hours. If no recent measured weight of the patient is available, the subject rule is disregarded and processed according to logic flow diagram  1000 , and step  704  (FIG. 7), completes.  
         [0077]    In test step  1008  (FIG. 10), dosage monitor  102  (FIG. 1) determines whether the dosage amount of the subject drug order is specified by the subject rule as allowable. Dosage monitor  102  (FIG. 1) determines whether the dosage amount of the subject drug order is included within the range or included in the one or more discrete amounts specified by the weighted allowable dosage amounts determined in step  1006 .  
         [0078]    If the dosage amount of the subject rule is not specified as allowable by the subject rule, processing transfers to step  1010  (FIG. 10) in which dosage monitor  102  determines that the subject drug order violates the subject rule and processing according to logic flow diagram  1000 , and thus, step  704  (FIG. 7), completes. Conversely, if the dosage amount of the subject rule is specified as allowable by the subject rule, processing transfers to test step  1012  (FIG. 10).  
         [0079]    In test step  1012 , dosage monitor  102  (FIG. 1) determines whether the dosage frequency of the subject drug order is specified by the subject rule as allowable in the manner described above with respect to test step  810  (FIG. 8).  
         [0080]    If the dosage frequency of the subject rule is not specified as allowable by the subject rule, processing transfers to step  1014  (FIG. 10) in which dosage monitor  102  determines that the subject drug order violates the subject rule and processing according to logic flow diagram  1000 , and thus, step  704  (FIG. 7), completes. Conversely, if the dosage amount of the subject rule is specified as allowable by the subject rule, processing transfers to step  1016  (FIG. 10) in which dosage monitor  102  (FIG. 1) determines that the subject drug order satisfies the subject rule and processing according to logic flow diagram  1000 , and thus, step  704  (FIG. 7), completes.  
         [0081]    Thus, according to logic flow diagram  1000 , dosage monitor  102  compares the dosage amount and dosage frequency of the subject drug order to limits weighted by the patient&#39;s calculated dosage weight in evaluating an amino rule.  
         [0082]    Dosage monitor  102  (FIG. 1) evaluates a drug order according to a first-value rule in step  704  in the manner shown in logic flow diagram  1100  (FIG. 11). Briefly, a first-value rule is an exception rule in which other rounding rules are inapplicable of the first-value rule is satisfied. The utility of first-value rules is described more completely below in conjunction with test step  712  (FIG. 7).  
         [0083]    In step  1102 , dosage monitor  102  (FIG. 1) retrieves the dosage amount and dosage frequency of the subject drug order from dosage alert candidates  302 . In step  1104  (FIG. 11), dosage monitor  102  converts the units of the dosage amount and frequency if necessary in the manner described above with respect to step  804 .  
         [0084]    In steps  1106 - 1108 , dosage monitor  102  ensures that the weight and creatinine clearance of the patient is sufficiently recent and within limits of applicable weights as specified in weight limits  408  (FIG. 4) and CrCl limits  406  of the subject rule in the manner described above with respect to steps  806 - 808  (FIG. 8).  
         [0085]    In test step  1110  (FIG. 11), dosage monitor  102  (FIG. 1) determines whether the dosage amount of the subject drug order is specified by the subject rule as allowable in the manner described above with respect to test step  810  (FIG. 8).  
         [0086]    If the dosage amount of the subject rule is not specified as allowable by the subject rule, processing transfers to step  1112  (FIG. 11) in which dosage monitor  102  determines that the subject drug order violates the subject rule and processing according to logic flow diagram  1100 , and thus, step  704  (FIG. 7), completes. Conversely, if the dosage amount of the subject rule is specified as allowable by the subject rule, processing transfers to test step  1114  (FIG. 11).  
         [0087]    In test step  1114 , dosage monitor  102  (FIG. 1) determines whether the dosage frequency of the subject drug order is specified by the subject rule as allowable in the manner described above with respect to test step  814  (FIG. 8).  
         [0088]    If the dosage frequency of the subject rule is not specified as allowable by the subject rule, processing transfers to step  1116  (FIG. 11) in which dosage monitor  102  determines that the subject drug order violates the subject rule and processing according to logic flow diagram  1100 , and thus, step  704  (FIG. 7), completes. Conversely, if the dosage amount of the subject rule is specified as allowable by the subject rule, processing transfers to step  1118  (FIG. 11) in which dosage monitor  102  (FIG. 1) determines that the subject drug order satisfies the subject rule and processing according to logic flow diagram  1100 , and thus, step  704  (FIG. 7), completes.  
         [0089]    Thus, according to logic flow diagram  1100 , dosage monitor  102  compares the dosage amount and dosage frequency of the subject drug order to absolute limits in evaluating a first-value rule.  
         [0090]    Dosage monitor  102  (FIG. 1) evaluates a drug order according to a peak-and-trough rule in step  704  in the manner shown in logic flow diagram  1200  (FIG. 12). Briefly, a peak-and- 5  trough rule specifies limits in drug levels in the patient&#39;s blood.  
         [0091]    In step  1202 , dosage monitor  102  (FIG. 1) retrieves the dosage amount and dosage frequency of the subject drug order from dosage alert candidates  302 . In step  1204  (FIG. 12), dosage monitor  102  converts the units of the dosage amount if necessary in the manner described above with respect to step  804 .  
         [0092]    In step  1206  (FIG. 12), dosage monitor  102  (FIG. 1) predicts peak and trough drug levels for the patient using the dosage amount and frequency and the patient&#39;s age and dosage weight. In one embodiment, dosage monitor  102  uses the following equations for predicting peak and trough blood levels of the subject drug:  
         Pr                 edictedPeak     =       [     D        (     1   -          -   Kt         )       ]       [       (     k   ×   Vd     )          (     1   -          -   KT         )       ]                             
 
         [0093]    In the above equation, (i) D is the dose (e.g., of gentamicin) expressed in mg/hour; (ii) K=(0.0024CrCl)+0.01;(iii)Vd=0.29 times the ideal body weight of the patient (or the obese dose weight of the patient when appropriate); (iv) T is the dosing interval; and (v) t is the infusion period expressed in hours. 
         Pr edictedtrough=Pr edicitedPeak×e −K(T−t)   
         [0094]    In the above equation, K, T, and t have the same meaning as in the previous equation. Obese dosing weight is calculated according to the following equation: 
         ObeseDoseWeight=IBW+0.4(ActualBodyWeight−IBW) 
         [0095]    In the above equation, IBW is the patient&#39;s ideal body weight.  
         [0096]    In test step  1208  (FIG. 12), dosage monitor  102  (FIG. 1) determines whether the predicted peak blood level of the subject drug order is specified by the subject rule as allowable. If rule  400  (FIG. 4) represents a peak-and-trough rule, dose limits  410  specify a maximum peak level and a minimum trough level. In test step  1208  (FIG. 12), dosage monitor compares the predicted peak level with the maximum allowable peak level.  
         [0097]    If the predicted peak blood level exceeds the maximum peak level specified as allowable by the subject rule, processing transfers to step  1210  (FIG. 12) in which dosage monitor  102  determines that the subject drug order violates the subject rule and processing according to logic flow diagram  1200 , and thus, step  704  (FIG. 7), completes. Conversely, if the predicted peak blood level does not exceed the maximum peak level specified as allowable by the subject rule, processing transfers to test step  1212  (FIG. 12).  
         [0098]    In test step  1212 , dosage monitor  102  (FIG. 1) determines whether the predicted trough blood level of the subject drug order is specified by the subject rule as allowable. In particular, dosage monitor  102  compares the predicted trough to the minimum allowable trough blood level specified in dose limits  410  in the manner described above.  
         [0099]    If the predicted trough blood level is below the minimum trough level specified as allowable by the subject rule, processing transfers to step  1214  (FIG. 12) in which dosage monitor  102  determines that the subject drug order violates the subject rule and processing according to logic flow diagram  1200 , and thus, step  704  (FIG. 7), completes. Conversely, if the predicted trough blood level is not below the minimum trough level specified as allowable by the subject rule, processing transfers to step  1216  (FIG. 12) in which dosage monitor  102  (FIG. 1) determines that the subject drug order satisfies the subject rule and processing according to logic flow diagram  1200 , and thus, step  704  (FIG. 7), completes.  
         [0100]    Thus, according to logic flow diagram  1200 , dosage monitor  102  compares the predicted peak and trough blood levels of the subject drug order to peak and trough limits in evaluating a peak-and-trough rule.  
         [0101]    In evaluating a rounding rule in step  704  (FIG. 7), dosage monitor  102  (FIG. 1) ensures that the dosage amount of the subject drug order is an integer multiple of round value  414  (FIG. 4) of the subject rule. If the dosage amount is an integer multiple of the round value, dosage monitor  102  determines that the subject rounding rule is satisfied. Conversely, if the dosage amount of the subject drug order is not an integer multiple of the round value, dosage monitor  102  determines that the subject drug order violates the subject rounding rule.  
         [0102]    Once all rules for the subject drug order have been evaluated in the loop of steps  702 - 706  (FIG. 7), dosage monitor  102  (FIG. 1) determines whether the various evaluated rules warrant an alert according to steps  708 - 728 . In test step  708 , dosage monitor  102  determines whether any peak-and-trough rule is satisfied by the subject drug order. Briefly, dosage monitor determines that a peak-and-trough rule is satisfied if a peak-and-trough rule exists for the drug of the subject drug order and the drug order satisfies the peak-and-trough rule and at least one rounding rule is satisfied if any are specified for the subject drug order. Test step  708  is shown in greater detail as logic flow diagram  708  (FIG. 13).  
         [0103]    In test step  1302 , dosage monitor  102  determines whether a peak-and-trough rule is specified for the subject drug order. If not, dosage monitor  102  determines that no peak-and-trough rule is satisfied in step  1304  and processing according to test step  708  (FIG. 7) completes. Conversely, if a peak-and-trough rule is specified for the subject drug order, processing transfers to test step  1306 .  
         [0104]    In test step  1306 , dosage monitor  102  determines whether at least one peak-and-trough rule for the subject drug order is satisfied. In not, dosage monitor  102  determines that no peak and trough rule is satisfied and processing terminates in step  1308 . Conversely, if at least one peak-and-trough rule is satisfied by the subject drug order, processing transfers to test step  1310 . Since only one of the peak-and-trough rules specified for the subject drug order must be satisfied, multiple peak-and-trough rules have a logical OR relationship with respect to one another.  
         [0105]    In test step  13   10 , dosage monitor  102  determines whether any rounding rules are specified for the subject drug order. If not, then at least one peak-and-trough rule is specified and satisfied and no rounding rules are specified. Accordingly, dosage monitor  102  determines that peak-and-trough analysis indicates that the subject drug order is allowable and processing according to logic flow diagram  708  terminates in step  1312 . If dosage monitor  102  determines that at least one rounding rule is specified for the subject drug order, processing transfers to test step  1314 .  
         [0106]    In test step  1314 , dosage monitor  102  determines whether any of the rounding rules specified for the subject rule are satisfied. If any of the rounding rules is satisfied, dosage monitor  102  determines, in test step  1314  to terminal step  1318 , that at least one peak-and-trough rule and at least one rounding rule of the subject drug order is satisfied and the drug order is allowable. Since only one rounding rule must be satisfied, rounding rules have a logical OR relationship to one another. If no rounding rule is satisfied by the subject rule, dosage monitor  102  determines, in step  1316 , that the subject rule is not allowable, specifically not properly rounded, in test step  708  (FIG. 7).  
         [0107]    Thus, in test step  708 , dosage monitor  102  determines whether any peak-and-trough rule is satisfied by the subject order and whether the subject order is properly rounded. If so, dosage monitor  102  determines that the subject order is allowable and logic flow diagram  608 , and therefore step  608  (FIG. 6), completes. Satisfaction of a peak-and-trough rule with proper rounding therefore terminates consideration of any other rules and the subject drug order is allowable. Conversely, if no peak-and-trough rule is specified for the subject drug order or if no peak-and-trough rule is satisfied by the drug order or if the drug order is not properly rounded, processing by dosage monitor  102  transfers to test step  712  (FIG. 7).  
         [0108]    In test step  712 , dosage monitor  102  determines whether the subject rule satisfies a first-value rule. If at least one first-value rule is specified for the subject drug order and at least one of those first-value rules is satisfied by the subject drug order, dosage monitor  102  determines that the subject order is allowable in step  714  and processing according to logic flow diagram  608 , and therefore step  608  (FIG. 6), terminates. It should be noted that, when evaluating first-value rules, violation of all rounding rules specified for the subject drug order is immaterial. In essence, first-value rules are exceptions to rounding rules. If dosage monitor  102  determines that there are no first-value rules specified or that no specified first-value rules are satisfied by the subject drug order, further analysis of allowable rules for the subject drug order is needed and processing transfers to test step  716 .  
         [0109]    In test step  716 , dosage monitor  102  determines whether at least one rounding rule and at least one other, non-rounding rule is satisfied by the subject drug order. If at least one rounding rule is specified for and satisfied by the subject rule and at least one non-rounding rule is specified for and satisfied by the subject rule, the subject drug order is allowable and no further analysis is needed. Accordingly, under such circumstances, dosage monitor  102  terminates processing in step  718  and determines that the subject rule is allowable. Otherwise, analysis of the subject drug order by dosage monitor  102  continues in test step  720 .  
         [0110]    In test step  720 , dosage monitor  102  determines whether no rounding rules are specified for the subject drug order and at least one non-rounding rule is specified for and satisfied by the subject drug order. If no rounding rules are specified for the subject drug order and at least one By. non-rounding rule is specified for and satisfied by the subject drug order, dosage monitor  102  determines that the subject drug order is allowable and no further analysis of the subject drug order is necessary. Accordingly, dosage monitor  102  terminates processing in step  722  and processing according to logic flow diagram  608 , and therefore step  608 , completes upon such circumstances. Conversely, if at least one rounding rule is specified and none are satisfied by the subject drug order or if no non-rounding rule is specified for and satisfied by the subject drug order, processing transfers to test step  724  and analysis by drug monitor  102  of the subject drug order continues.  
         [0111]    In test step  724 , dosage monitor  102  determines whether only rounding rules are specified for the subject drug order and whether any of those are satisfied by the subject drug order. If only rounding rules are specified for the subject drug order and any of those rounding rules are satisfied by the subject drug order, dosage monitor  102  determines that the subject drug order is allowable and terminates processing of logic flow diagram  608 , and therefore step  608 , in step  726 . Conversely, if any non-rounding rules are specified for the subject drug order or if no rounding rules are satisfied by the subject drug order, dosage monitor  102  determines in step  728  that the subject drug order is not allowable and processing according to logic flow diagram  608 , and therefore step  608 , terminates.  
         [0112]    As described above, dosage monitor  102  alerts a clinician in step  610  of any drug order which is determined not to be allowable according to allowable rules  304  (FIG. 3). Step  610  is shown in greater detail as logic flow diagram  610  (FIG. 14).  
         [0113]    In step  1402 , dosage monitor  102  retrieves a recommendation for the subject drug order from recommendations  306 . As described above, recommendations  306  express proper dosage amounts, dosage frequencies, and rounding values for specific drugs, typically in ranges narrower than the ranges which trigger alerts as expressed in allowable rules  304 .  
         [0114]    In step  1404 , dosage monitor  102  converts the units of the retrieved recommendation to the units of the subject drug order if the units are different. Thus, when the alert is received by the clinician, the recommended dosage amount and frequency is easily compared to the originally ordered dosage amount and frequency.  
         [0115]    In step  1406 , dosage monitor  102  weights recommended dosage amounts (i) by the measured actual weight of the patient of the subject drug order if the subject drug order type is “multiplied” or (ii) by the calculated dosage weight of the patient of the subject drug order if the subject drug order type is “amino.” Accordingly, the recommendation is specific to the patient&#39;s condition as represented in patient 3  s records  202  and laboratory results  204 .  
         [0116]    In step  1408 , dosage monitor  102  constructs an alert record from the unit-converted and properly weight dosage amount and frequency recommendations and places the alert record on an alert queue which is described more completely below. Alert manager  114  subsequently alerts a clinician to the improper dosing of the patient of the subject drug order and provides the clinician with the recommended dosing information.  
         [0117]    Thus, in accordance with the present invention, dosage monitor  102  monitors drug orders and patient information and notifies a clinician if any improper dosing is detected. As described above, dosage monitor  102  responds to triggers which are activated when any new drug order is stored. Accordingly, drug orders for all patients are concurrently analyzed by drug monitor  102  in the manner described above.  
         [0118]    ADE Monitor  
         [0119]    As described above, ADE monitor  104  (FIG. 1) monitors drug orders  206  to detect possible drug-drug interactions and drug duration violations. ADE monitor  104  also analyzes laboratory results  204  to detect laboratory results whose values are outside predetermined allowable ranges. Such allowable ranges are sometimes referred to herein as panic labs. ADE monitor records  210  are shown in greater detail in FIG. 3.  
         [0120]    ADE monitor records  210  include ADE monitor candidates  1502 , ADE panic labs  1504 , ADE interactions  1506 , ADE pertinent data  1508 , and ADE workspace  1510 . ADE monitor candidates  1502  stores records representing newly prescribed drug orders and/or newly received laboratory results as candidates for ADE analysis by ADE monitor  104 .  
         [0121]    ADE panic labs  1504  store redetermined acceptable ranges of laboratory result values. Laboratory result values which lie outside such acceptable ranges can indicate an adverse drug effect and are alerted by ADE monitor  104 .  
         [0122]    ADE interactions  1506  stores records representing interaction relationships between drugs. Interaction can occur when two incompatible drugs are simultaneously prescribed and when one drug order follows too soon after a second, incompatible drug order. These latter sequential interactions can be either order-dependent or order-independent.  
         [0123]    ADE interactions  1506  also stores records representing maximum duration of drug orders. For example, Ketorolac can only be given for a maximum of five (5) days. Such a limitation is specified in ADE interactions  1506 .  
         [0124]    ADE pertinent data  1508  stores records representing additional data needed by a clinician to help in the assessment of the patient&#39;s status or potential harm. For example, an ADE interaction may be more severe if the patient is on a third drug that can accelerate the adverse symptoms of the drug-drug interaction. ADE pertinent data  1508  includes drug orders, laboratory results, and information pertaining to the type of alert.  
         [0125]    ADE workspace  1510  is used by ADE monitor  104  as workspace for analyzing new drug orders for ADE issues.  
         [0126]    ADE analysis as performed by ADE monitor  104  is illustrated by logic flow diagram  1600  (FIG. 16). Loop step  1602  and next step  1608  define a loop in which each new drug order represented in ADE monitor candidates  1502  is processed according to steps  1604 - 1606 . During each iteration of the loop of steps  1602 - 1608 , the particular drug order processed according to steps  1604 - 1606  is sometimes referred to as the subject drug order.  
         [0127]    In test step  1604 , ADE monitor  104  determines whether the subject drug order has started or will start within a predetermined amount of time by reference to the start date and time as represented in the subject drug order. If the subject drug order has started, processing transfers to step  1606  in which ADE monitor  104  analyzes the subject drug order for ADE risk in a manner described more completely below. If the subject drug has not yet started, ADE monitor skips step  1606  and the subject drug order is not processed until a subsequent performance of the steps of logic flow diagram  1600  once the subject drug order has indeed started.  
         [0128]    Once all new drug orders have been processed according to the loop of steps  1602 - 1608 , ADE monitor  104  logs and reports ADE monitor results in step  1610 .  
         [0129]    Loop step  1612  and next step  1616  define a loop in which each new laboratory result represented in ADE monitor candidates  1502  is processed according to step  1614 . During each iteration of the loop of steps  1612 - 1616 , the particular laboratory result processed according to step  1614  is sometimes referred to as the subject laboratory result.  
         [0130]    In step  1614 , ADE monitor  104  analyzes the subject laboratory result for ADE indication in a manner described more completely below.  
         [0131]    Once all new laboratory results have been processed according to the loop of steps  1612 - 1616 , ADE monitor  104  logs and reports ADE monitor results in step  1618 .  
         [0132]    ADE analysis by ADE monitor  104  in step  1606  when triggered by a new drug order is shown in greater detail as logic flow diagram  1606  (FIG. 17). In step  1702 , ADE monitor  104  determines to which patient the subject drug order pertains (sometimes referred to as the subject patient) and retrieves all drug orders and laboratory results of the subject patient.  
         [0133]    In step  1704 , ADE monitor  104  evaluates the subject patient&#39;s drug order and laboratory results for ADE risks. Step  1704  is shown in greater detail as logic flow diagram  1704  (FIG. 18).  
         [0134]    In test step  1802 , ADE monitor  104  determines whether a drug order for the subject patient exceeds the allowable duration as represented in ADE interactions  1506 . If so, processing transfers to step  1804  in which ADE monitor  104  builds an alert message including identification and location of the subject patient, the drug order whose excessive duration triggers the ADE alert, and the nature of the potential ADE as represented in ADE pertinent data  1508  (FIG. 15).  
         [0135]    Whether from step  1804  (FIG. 18) or from test step  1802  when no order for an indicator drug is found for the subject patient, processing transfers to test step  1806 . In test step  1806 , ADE monitor  104  determines whether the subject patient has concurrent drug orders for drugs that interact with one another when concurrently administered. If a drug currently administered to the patient interacts adversely with another drug currently administered to the subject patient according to ADE interactions  1506  (FIG. 15), ADE monitor  104  builds an alert message including identification and location of the subject patient, the concurrently interacting drugs triggering the ADE alert, and the nature of the potential ADE as represented in ADE recommendations  1508  (FIG. 15) in step  1808  (FIG. 18). If no currently administered drug of the subject patient interacts with any other currently administered drug of the subject patient, step  1808  is skipped.  
         [0136]    In test step  1810 , ADE monitor  104  determines whether a currently administered drug of the subject patient interacts with a recently administered drug of the subject patient and the time lapsed between the former drug and the current drug is less than a predetermined threshold time. The interacting drugs and the predetermined threshold lapse between drugs are specified in ADE interactions  1506 . In test step  1810 , the order of the drugs is significant as specified in ADE interactions  1506 . If a currently administered drug of the subject patient follows administration of a recently administered, interacting drug of the subject patient within the predetermined threshold time, processing transfers to step  1812 .  
         [0137]    In step  1812 , ADE monitor  104  builds an alert message including identification and location of the subject patient, the sequentially interacting drugs triggering the ADE alert, and the nature of the potential ADE as represented in ADE recommendations  1508  (FIG. 15). If no currently administered drug of the subject patient interacts with any recently administered drug of the subject patient in an order-dependent manner, step  1812  is skipped.  
         [0138]    In test step  1814 , ADE monitor  104  determines whether a currently administered drug of the subject patient interacts with a recently administered drug of the subject patient and the time lapsed between the former drug in an order-independent manner and the current drug is less than a predetermined threshold time. The interacting drugs and the predetermined threshold lapse between drugs are specified in ADE interactions  1506 . In test step  1814 , the order of the drugs is insignificant as specified in ADE interactions  1506 . If a currently administered drug of the subject patient follows administration of a recently administered, interacting drug of the subject patient within the predetermined threshold time, processing transfers to step  1816 .  
         [0139]    In step  1816 , ADE monitor  104  builds an alert message including identification and location of the subject patient, the sequentially interacting drugs triggering the ADE alert, and the nature of the potential ADE as represented in ADE recommendations  1508  (FIG. 15). If no currently administered drug of the subject patient interacts with any recently administered drug of the subject patient in an order-independent manner, step  1816  is skipped.  
         [0140]    After steps  1814 - 1816 , processing according to logic flow diagram  1704 , and therefore step  1704  (FIG. 17), completes. It should be noted that a single drug order for the subject patient can generate multiple alert messages in logic flow diagram  1704 . For example, one drug can interact adversely with both a currently administered drug and a recently administered drug of the subject patient.  
         [0141]    In step  1706  (FIG. 17), ADE monitor  104  places all alert messages built in step  1704  on the alert queue for subsequent processing by alert manager  114  in the manner described below. After step  1706 , processing according to logic flow diagram  1606 , and therefore step  1606  (FIG. 16), completes.  
         [0142]    ADE analysis by ADE monitor  104  in step  1614  when triggered by a new laboratory result is shown in greater detail as logic flow diagram  1614  (FIG. 19). In test step  1902 , ADE monitor  104  determines whether the subject laboratory result lies outside a predetermined range of allowable laboratory result values as represented in ADE panic labs  1504 . If so, ADE monitor  104  determines that the subject laboratory result can be an indication of an ADE in the subject patient and builds an alert message and place the alert message in the alert queue in step  1904 . The alert message includes identification and location of the subject patient, the laboratory result triggering the ADE alert, and the nature of the potential ADE as represented in ADE recommendations  1508  (FIG. 15). Conversely, if the subject laboratory result lies within the predetermined range of allowable laboratory result values as represented in ADE panic labs  1504  (FIG. 15), step  1904  (FIG. 19) is skipped.  
         [0143]    After steps  1902 - 1904 , processing according to logic flow diagram  1614 , and therefore step  1608  (FIG. 16), completes.  
         [0144]    Thus, ADE monitor  104  analyzes drug orders and laboratory results of individual patients for potential ADE risks and notifies a clinician of the potential ADE in sufficient time that the ADE can be averted.  
         [0145]    Alert Manager  
         [0146]    Alert manager  114  (FIG. 1) processes alert messages on an alert queue to send the alert messages to appropriate clinicians for evaluation and corrective action. Processing by alert manager  114  is shown by logic flow diagram  2000 . Loop step  2002  and next step  2018  define a loop in which each alert message on the alert queue is processed according to steps  2004 - 2016 . During each iteration of the loop of steps  2002 - 2018 , the particular alert message processed is sometimes referred to as the subject alert message. Alert manager  114  (FIG. 1) processes the alert messages of the alert queue according to logic flow diagram  2000  continually and periodically. It is generally not necessary to process alert messages more frequently than once every five (5) minutes but it is preferred that alert messages are processed no less frequently than once every thirty (30) minutes.  
         [0147]    In step  2004 , alert manager  114  retrieves information of the patient of the subject alert message and priority information of the subject alert message. In this illustrative embodiment, there are two levels of priority. Urgent priority is assigned to alert messages pertaining to potentially life-threatening ADEs. Normal priority is assigned to all other alerts. Low-risk situations are not alerted at all in this illustrative embodiment to avoid desensitizing clinicians to alert messages.  
         [0148]    In test step  2006 , alert manager  114  determines whether the subject alert message pertains to an ADE alert from ADE monitor  104  or to a dosage alert from dosage monitor  102 . If the subject alert message pertains to an ADE alert, alert manager  114  formats the subject alert message for representation as an ADE alert in step  2008 . Conversely, if the subject alert message pertains to a dosage alert, alert manager  114  formats the subject alert message for representation as a dosage alert in step  2010 .  
         [0149]    Alert manager  114  formats an ADE alert message in step  2008  by presenting the various information of the alert message in a readable manner, including the patient&#39;s name and location and a brief description of the particular reason for the ADE alert. The brief description can be “Drug interaction (both orders currently active)” or “Drug interaction (one order follows another too closely)” for example. ADE manager  114  also formats data representing the interacting drug orders, including drug identification, name, dosage amount, frequency, and order start and stop dates, in a readable manner for easy interpretation by the clinician. An example of an ADE alert message is shown in FIG. 23 as a screen view of an ADE alert report in HTML format.  
         [0150]    Alert manager  114  formats a dosage alert message in step  2010  by presenting the various information of the alert message in a readable manner, including the patient&#39;s name and location, the drug order to which the dosage alert pertains, and the recommended dosage of the drug order as retrieved from recommendations  306  (FIG. 3). FIG. 25 shows a screen view of a dosage alert in HTML format. FIG. 26 shows a more detailed report of a dosage alert available to the clinician receiving the alert.  
         [0151]    After either step  2008  or step  2010 , alert manager  114  (FIG. 1) sends the formatted alert message to a designated clinician by electronic mail (e-mail). In this illustrative embodiment, the designated clinician is a pharmacist. Pharmacists are particularly capable of assessing the risks involved with alerted drug orders. If the pharmacist determines that the dosing error or the ADE risk associated with interacting drug orders possesses a serious risk to the patient, the pharmacist consults with the physician caring for the particular patient and the pharmacist and physician together arrive at a course of treatment. Alert manager  114  determines to which clinician to send the e-mail according to scheduled contact information. Such scheduled contact information specified which clinicians are to receive ADE and dosage alerts during which times of the day for each day of the week. The scheduled contact information can be modified as work schedules change for various clinicians. The particular clinician to whom alert messages are to be directed according to the scheduled contact information is sometimes referred to as the designated clinician.  
         [0152]    In test step  2014 , alert manager  114  determines whether the subject alert message has urgent priority. If so, alert manager  114  sends the alert message through various channels in an attempt to capture the attention of the designated clinician. For example, in this illustrative embodiment, alert manager  114  sends the formatted subject alert message to an alphanumeric pager, a printer, and a fax machine. Each of these devices, along with a network address for reaching the device, is specified in the scheduled contact information. If the subject alert message is not urgent, step  2016  is skipped by alert manager  114 .  
         [0153]    After steps  2014 - 2016 , alert manager  114  processes the next alert message according to the loop of steps  2002 - 2018  until all alert messages have been processed. Once an alert message is processed by alert manager  114 , the alert message is not immediately removed from the alert queue. Instead, the alert message remains on the alert queue until the designated clinician, or another clinician, removes the alert. The clinician can remove the alert by sending a user-generated signal indicating that the alert is acknowledged but disregarded, by sending a user-generated signal representing a change in the drug order or orders to which the alert pertains. FIG. 24 shows an HTML form by which the clinician acknowledges and ADE alert and enters the outcome of the alerted condition. FIG. 26 shows an HTML form by which the clinician acknowledges a dosage alert and enters data representing the outcome of the alerted condition.  
         [0154]    Logic flow diagram  2100  (FIG. 21) shows processing by alert manager  114  when alert messages have been in the alert queue for at least a predetermined period of time, e.g., one hour. Such alert messages are sometimes referred to herein as old alert messages. Loop step  2102  and next step  2116  define a loop in which each old alert message is processed according to steps  2104 - 2114 . During each iteration of the loop of steps  2102 - 2116 , the particular old alert message processed by alert manager  114  is sometimes referred to as the subject old alert message.  
         [0155]    In test step  2104 , alert manager  114  determines whether the subject old alert message has been acknowledge, e.g., by use of the HTML forms of either FIG. 24 or FIG. 26. If the subject old alert message has been acknowledged, alert manager  114  deletes the subject old alert message from the alert queue in step  2106  and the next old alert message is processed according to the loop of steps  2102 - 2116 . Conversely, if the subject old alert message has not been acknowledged, processing transfers from test step  2104  to test step  2108 .  
         [0156]    In test step  2108 , alert manager  114  determines the number of times the subject old alert message has been sent. Alert manager  114  maintains a times-sent record for each alert message in the alert queue. If the subject old alert message has been sent less than three times before, alert manager  114  re-sends the subject old alert message in step  2110  and records the time of last sending for the subject old alert message in the alert queue. If, on the other hand, the subject old alert message has been sent at least three times before, alert message escalates the alert message in step  2114 .  
         [0157]    Alert manager  114  escalates an alert message by including an escalation banner in the alert message to indicate the urgency of the alert message. In addition, alert manager  114  sends the alert message to a wireless telephone as a voice message and/or to a pager according to the scheduled contact information, in addition to the other methods of alert message delivery described above.  
         [0158]    Thus, alert manager  114  processes alerts from both dosage monitor  102  and ADE monitor in an orderly manner and ensures that the alert messages go to the appropriate person. In addition, if an alert message goes unacknowledged for a predetermined amount of time, alert manager  114  escalates the alert message and tries more direct methods of reaching a designated clinician. In this manner, alert manager  114 , dosage monitor  102 , and ADE monitor  104  cooperate to reduce significant risks associated with ADEs and dosage errors and do so without significant interruption of the daily routines of clinicians serving the needs of patient in a healthcare organization.  
         [0159]    Alert Viewing  
         [0160]    Alert manager  114  providers users with the ability to view alert summaries or details via a wide area computer network such as the World Wide Web (the WEB). At the summary level, alert manager  114  provides a full range of sorting options including alert date, alert severity, alert destination, patient name, etc. Full ranges of filtering options are also available including: alert destination, alert date ranges, alert severity, etc. The summary page provides a link to the detailed information about an alert. At the detail level, all relevant information about an alert is visible as well as links to specific information about the drugs that are in question.  
         [0161]    The alert links can be referenced from any other WEB based application, which makes it easy to include Drug Alert information in a patient medical record.  
         [0162]    Rule Viewing and Writing  
         [0163]    Dosage monitor  102  and ADE monitor  104  provider users with the ability to view the rules for drugs within the system  100 . The interface provides filtering options for drug name, implementation date, firing frequency, alerting frequency and rule status (e.g. development, test, production). Rules can be sorted by drug name, implementation date, firing frequency, alerting frequency and rule status. Printing is fully functional. All users are allowed to view alerts.  
         [0164]    This interface also provides an authorized user to write new rules. The interface does extensive error checking to ensure that rules meet the criteria of the application and gives explicit guidance where errors are discovered. Users select the rule type they wish to create (e.g. drug-drug interaction, drug dosing, drug-lab, drug-allergy) and are then presented with the information that needs to be completed to write the rules. Selection lists are available for most fields so that the user can specify difficult-to-remember items easily. The system is designed so that many users can write rules and monitor their performance. However, it takes an administrator of the system to move rules from test into production. This provides the capability to control the rules that are operating within an environment.  
         [0165]    Outcome Entry and Analysis  
         [0166]    For each drug alert, a customized outcome form exists. This form is sent via fax to the appropriate user along with the alert information. Users may either respond to an alert by entering the outcome information via the WEB (accessible from the Alert Viewing application) or by completing the form and faxing it back to an information systems group where it is scanned and entered into the database.  
         [0167]    Several analysis and reporting processes exist to analyze the effectiveness of the clinical decision support applications. These procedures also help identify differences between pharmacist agreement rates by drug, hospital location, and individual user. Using this information, an institution can identify rules that may need adjustments or clinical staff that may need additional training regarding the clinical information that dosage monitor  102  presents.  
         [0168]    The application contains several reports and charts which can be displayed on the WEB. The application also contains a robust data extraction process, including ODBC capabilities which allow users to use their own reporting and analysis tools (e.g. Excel, SAS, Crystal Reports).  
         [0169]    The above description is illustrative only and is not limiting. Instead, the present invention is defined solely by the claims which follow and their full range of equivalents.