Abstract:
A system for automatically providing a continuous flow of metoprolol intravenously to a patient, including a supply of metoprolol solution, a pump connected in fluidic communication with the supply of metoprolol solution, an electronic controller operationally connected to the pump, a vascular access device connected in liquid communication to the pump, and at least one sensor operationally connected to the pump. The pump provides a continuous flow of metoprolol through the vascular access device and the at least one sensor provides data regarding a patient&#39;s physical condition to the electronic controller. The electronic controller may control the pump to vary the flow rate of metoprolol in response to data from the at least one sensor and may generate an alarm signal in response to data from the sensor falling outside of predetermined parameters.

Description:
TECHNICAL FIELD 
       [0001]    The invention relates generally to the field of medicine and, specifically, to a method and apparatus for providing the continuous infusion of metoprolol to a patient. 
       BACKGROUND 
       [0002]    Metoprolol is a one of the most commonly prescribed member of a class of drugs called beta-blockers (also known as beta-adrenergic blocking agents or beta-receptor antagonists). Beta-blockers work by blocking the effects of catecholamines such as epinephrine on the beta-receptors located within the heart, kidney, and other organ systems. Beta-blockers also reduce sympathetic nervous system activity by decreasing the release of the hormone renin from the kidney and by reducing the amount of sympathetic nervous system activity originating in the brain. The resulting effect on the heart is a decrease in heart rate (negative chronotropic effect) and a decrease in the strength of contraction of the heart (negative inotropic effect). The drugs have been shown to help decrease blood pressure, stabilize heart rhythm, decrease the frequency of heart-related chest pains (i.e. angina), decrease the risk of heart attack, and decrease the risk of sudden cardiac death. Clinically, beta-blockers such as metoprolol are currently highly recommended and widely used for the treatment of high blood pressure, stable/unstable angina (heart-related chest pains), acute myocardial infarction (heart attack), coronary artery disease, congestive heart failure, and atrial fibrillation (an irregular rhythm of the heart). 
         [0003]    Given its widespread utilization, many patients are taking oral metoprolol prior to being hospitalized. Current medical practice recommends that patients be continued on their metoprolol during their hospital stay as discontinuing the drug can lead to life-threatening complications including severe hypertension, heart rhythm problems, myocardial infarction, and death. In addition, during hospitalization, many patients develop one of the above medical conditions that would benefit from metoprolol therapy. Thus, there is a need within two large populations of patients to continue or start taking metoprolol therapy during their hospitalization. 
         [0004]    Metoprolol is typically administered orally. Unfortunately, despite a documented clinical need for the drug, many patients cannot take oral metoprolol during hospitalization. These include the following groups of patients:
   1. Patients who are NPO (nil per os-no oral intake) for any reason.   2. Patients who are unable to take oral medications due to dysphagia, swallowing difficulties, mental status changes, or stroke.   3. Patients who are critically ill (i.e. on a ventilator) whose condition make it not possible or not safe to administer oral medications.   4. Patients who are unable to take oral medications due to abnormalities of their gastrointestinal tract (i.e. ileus, bowel obstruction, recent abdominal surgery, pancreatitis).   5. Patients who recently underwent surgery and are unable to take oral medications during the early-postoperative time period.   
 
         [0010]    Thus, there is a need for an alternative to oral metoprolol for these patients. The present invention addresses this need. 
       SUMMARY 
       [0011]    The present invention relates to a system and method for providing metoprolol to patients. One object of the present invention is to provide an improved means for administering metoprolol to patients. Related objects and advantages of the present invention will be apparent from the following description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a perspective view of a metoprolol delivery system according to a first embodiment of the present novel technology. 
           [0013]      FIG. 2  is a perspective view of a metoprolol delivery system according to a second embodiment of the present novel technology. 
           [0014]      FIG. 3  is a perspective view of a metoprolol delivery system according to a third embodiment of the present novel technology. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0015]    For the purposes of promoting an understanding of the principles of the invention and presenting its currently understood best mode of operation, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, with such alterations and further modifications in the illustrated device and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. 
         [0016]    As illustrated in  FIG. 1 , a first embodiment of the present novel technology relates to a system  10  for the continuous infusion of metoprolol to a patient. The system  10  includes a metoprolol supply  12 . Metoprolol source  12  is typically a 50 or 100 mg bag, although bags or containers of other sizes may be selected as desired. The metoprolol source  12  may contain a standard concentration of metoprolol, akin to that found in 5 mg single-dosage vials (typically 1 mg/ml), or, alternately, may contain a metoprolol solution having a lower (or greater) metoprolol concentration. The metoprolol source is in liquid communication with an infusion device  13 . The infusion device  13  is typically a pump, but may be a stopcock, electronically controlled valve, or the like. The infusion device  13  is connected in liquid communication with catheter  16  or like device for insertion into communication with a patient&#39;s circulatory system. A heart rate sensor  26  is connected in electric communication to a telemetry system  18 , typically either via direct wire connection or wirelessly to a remotely located telemetry system  18 . The patient&#39;s blood pressure is periodically measured, either via manual or automatic blood pressure cuff or the like. The infusion device  13  typically delivers a steady infusion rate of metoprolol to the patient, with the rate selected to match the prior dosage of metoprolol (or other beta-blocker) that the patient was taking orally prior to hospitalization. While the actual patient dosing schedule would be determined by the patient&#39;s physician and would be based on clinical data, one such exemplary schedule is provided below for illustrative purposes as Table 1: 
         [0000]                                                                      Loading   Continous           Dose   Infusion           IV   IV       Oral Medications   Metoprolol   Metoprolol            Atenolol   Carvedilol   Coreg CR   Metoprolol   Toprol XL   Bolus   Infusion                 25 mg PO    3.125/6.25   10/20 mg    25 mg PO    50 mg PO daily    5 mg   2 mg/hr       daily   PO bid   PO daily    bid                     50 mg PO   12.5 mg PO    40 mg PO    50 mg PO   100 mg PO daily   10 mg   4 mg/hr       daily   bid   daily   bid                   100 mg   25 mg PO   80 mg PO   100 mg PO    200 mg PO daily   15 mg   6 mg/hr       PO daily   bid   daily   bid                    
Alternatively, the infusion device  13  may be set to deliver an empirically or clinically determined rate of infusion if the patient&#39;s prior dose of beta blocker is unknown or if the patient has not been on a beta blocker agent previously.
 
         [0017]    A nurse or technician records and reviews the results of the heart rate and blood pressure values, such as in a paper chart, electronic medical record, or the like. Subsequently, through an order set, written algorithm, computer program, calculator or the like, the nurse makes adjustments to the infusion device  13  to correct the dose of metoprolol infusion based on patient&#39;s hemodynamic and clinical status. 
         [0018]    In a second embodiment, the system  10  is similar to the one discussed above, but with heart rate and blood pressure sensors  26 ,  28  connected, either directly or wirelessly, to a telemetry or hemodynamic monitoring system  18 . The nurse records and reviews the results of the heart rate and blood pressure values, either in a paper chart, electronic medical record or the like. Subsequently, typically through an order set, written algorithm, computer program, calculator or like, the nurse makes adjustments to the infusion device  13  to correct the dose of metoprolol infusion based on patient&#39;s hemodynamic and clinical status. 
         [0019]    In a third embodiment system  10 ′, as shown in  FIG. 2 , the system  10 ′ is similar to the first and second embodiments discussed above, but with the heart rate and blood pressure sensors  26 ,  28  connected either directly or wirelessly to a telemetry or hemodynamic monitoring system  18 , which is connected to send the heart rate and blood pressure values to the patient&#39;s electronic medical record  41 . A nurse or technician reviews the results in the electronic medical record and subsequently, such as through an order set, written algorithm, computer program, calculator or like, makes adjustments to the infusion device  13  to correct the dose of metoprolol infusion based on patient&#39;s hemodynamic and clinical status. 
         [0020]    In a fourth embodiment system  10 ′, the system  10 ′ is similar to those discussed above but with the heart rate and blood pressure sensors  26 ,  28  connected, either directly or wirelessly, to a telemetry or hemodynamic monitoring system  18  which is connected to send the heart rate and blood pressure values directly into the patient&#39;s electronic medical record  41 . The electronic medical record  41  is operationally connected to a microprocessor  43  which applies the hemodynamic data to an internal computer program, which calculates and provides directions to the nurse on making adjustments to the dose of metoprolol infusion, based on the patient&#39;s hemodynamic and clinical status. 
         [0021]    A fifth embodiment system  10 ″, as shown in  FIG. 3 , includes a metoprolol supply  12  in liquid communication with an infusion pump  14 . The pump  14  is connected in liquid communication with catheter  16  or like device for insertion into a patient&#39;s circulatory system. The pump  14  is operationally connected to an electronic controller  18  for governing the flow rate of the metoprolol through the catheter  16 . 
         [0022]    The metoprolol supply  12  is typically connected to the pump  14  via first tubing  20 , and the pump  14  is typically connected to the catheter  16  via second tubing  22 . Typically, a first sensor  26  is operationally connected to the electronic controller  18 . The first sensor  26  may be a blood pressure sensor, for example, and is operationally connectable to the patient for providing substantially real time blood pressure data to the electronic controller  18 . 
         [0023]    More typically, a second sensor  28 , such as for measuring a patient&#39;s heart rate, is operationally connected to the electronic controller  18  and is likewise operationally connectable to the patient for providing substantially real-time heart rate data to the electronic controller  18 . Still more typically, a third sensor  30 , such as for directly measuring the concentration of metoprolol in the patient&#39;s blood, is operationally connected to the electronic controller  18  and is likewise operationally connectable to the patient for providing substantially real-time metoprolol concentration data to the electronic controller  18 . 
         [0024]    Metoprolol source  12  is typically a 50 or 100 mg bag, although bags or containers of other sizes may be selected as desired. Pump  14  is typically a standard intravenous pump as is known in the art. Catheter  16  may be of any convenient vascular access device design for insertion into a central or peripheral vein. 
         [0025]    The metoprolol source  12  may contain a standard concentration of metoprolol, akin to that found in 5 mg single-dosage vials (typically 1 mg/ml), or, alternately, may contain a metoprolol solution having a lower (or greater) metoprolol concentration. In one embodiment, the electronic controller  18  may be configured to control the pump  14  to provide a predetermined, steady infusion rate of metoprolol to the patient, with the rate selected to match the prior dosage of metoprolol (or other beta-blocker) that the patient was taking orally prior to hospitalization. While the actual patient dosing schedule would be determined by the patient&#39;s physician and would be based on clinical data, one such exemplary schedule is provided below for illustrative purposes as Table 1: 
         [0000]                                                                      Loading   Continous           Dose   Infusion           IV   IV       Oral Medications   Metoprolol   Metoprolol            Atenolol   Carvedilol   Coreg CR   Metoprolol   Toprol XL   Bolus   Infusion                 25 mg PO    3.125/6.25   10/20 mg    25 mg PO    50 mg PO daily    5 mg   2 mg/hr       daily   PO bid   PO daily    bid                     50 mg PO   12.5 mg PO    40 mg PO    50 mg PO   100 mg PO daily   10 mg   4 mg/hr       daily   bid   daily   bid                   100 mg   25 mg PO   80 mg PO   100 mg PO    200 mg PO daily   15 mg   6 mg/hr       PO daily   bid   daily   bid                    
Alternatively, the electronic controller  18  may be configured to control the pump  14  and deliver an empirically or clinically determined rate of infusion if the patient&#39;s prior dose of beta blocker is unknown or if the patient has not been on a beta blocker agent previously.
 
         [0026]    In a sixth embodiment system  10 ″, the electronic controller  18  is configured to control the pump  14  to deliver metoprolol at a default flow rate similar to that described above, and is also configured to vary the flow rate based on data provided by one or more of the sensors  26 ,  28 ,  30 . The electronic controller  18  is programmed to decrease the flow of metoprolol if the data received from the sensors  26 ,  28 ,  30  indicates that the patient has received an excess dosage, and to increase the flow of metoprolol if the data indicates that the patient has not yet received a sufficient dosage. In other words, the electronic controller  18  is programmed to compare the data received from the sensors  26 ,  28 ,  30  with predetermined parameters, such as tabulated data, mathematical relationships, or the like, and vary the flow of metoprolol according to the results. For example, if the patient&#39;s blood pressure and/or heart rate are too high, the flow of metoprolol may be incrementally increased until either a maximum cap flow rate is achieved or the measured blood pressure and/or heart rate decreases below a predetermined level. 
         [0027]    In a seventh embodiment system  10 ″, the electronic controller  18  is configured to control the pump  14  to deliver metoprolol at a default flow rate similar to that described above, and is also configured to compare the data received from the sensors  26 ,  28 ,  30  with predetermined parameters, such as tabulated data, mathematical relationships, or the like, to calculate one or more recommended courses of action based on the same, and to display the calculated course(s) of action to the appropriate medical personnel. For example, if the patient&#39;s blood pressure and/or heart rate are too high, the electronic controller  18  may display a recommendation that the flow of metoprolol be increased by a predetermined amount so that the measured blood pressure and/or heart rate decreases below a predetermined level. The electronic controller  18  may also recommend other medications, procedures, physician attendance to the patient, or the like. 
         [0028]    In an eighth embodiment system  10 ″, the electronic controller  18  may be configured to generate an alert signal if a patient&#39;s heart rate and/or blood pressure and/or other like physical conditions, as measured by sensors  26 ,  28 ,  30  fall outside of predetermined parameters. Such a signal would alert hospital personnel to manually change the flow rate of the metoprolol and/or take whatever other steps necessary to bring the patient&#39;s physical metrics (i.e., heart rate and/or blood pressure and the like) back into the predetermined parameters. 
         [0029]    In a ninth embodiment system  10 ″, the electronic controller  18  is configured to both vary the flow rate of metoprolol to keep the patient&#39;s blood pressure and/or heart rate and the like, as measured by sensors  26 ,  28 ,  30  within a predetermined set of parameters and to also generate an alert signal when the patient&#39;s blood pressure and/or heart rate or the like falls outside the scope of those measured parameters. 
         [0030]    It should be recognized that the above embodiments are not mutually exclusive. 
         [0031]    While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character. It is understood that the embodiments have been shown and described in the foregoing specification in satisfaction of the best mode and enablement requirements. It is understood that one of ordinary skill in the art could readily make a nigh-infinite number of insubstantial changes and modifications to the above-described embodiments and that it would be impractical to attempt to describe all such embodiment variations in the present specification. Accordingly, it is understood that all changes and modifications that come within the spirit of the invention are desired to be protected.