Ask the Experts (2007)

Q We are having an ongoing debate with anesthesia about compatibility of drips going into “manifolds” (devices with multiple ports/stopcocks). The manifold is then attached directly to the catheter lumen, often with a flush behind it. Compatibility charts frequently say the drips are not compatible, yet the patients come to us with drips running.A Earnest Alexander, PharmD, replies:Intensive care unit (ICU) nurses who care for high-acuity patients receiving numerous intravenous (IV) medications may feel that the choices and options for safe and effective drug delivery are diminished when the pharmacist or a drug administration handbook state that 2 or more of the agents are incompatible. In many instances, the incompatible drugs are already infusing together before the investigation ensues and the problem has been identified. In all cases, upfront dialogue among nurses, physicians, and pharmacists regarding which combinations of these IV medications may be administered concurrently is needed to identify potential barriers to safe drug delivery.Surgical, transplant, and burn ICU patient populations tend to be at highest risk of running into drug compatibility problems because of the use of manifolds or bridging ports, in which multiple medications are delivered via 1 main catheter lumen, in this patient population. In these situations, the debate wages on regarding the IV compatibility data (or lack thereof ) and the real needs of the patient for IV medications.If coadministration of incompatible agents is unavoidable, the agents should be infused as far apart as possible while bridging or via manifold (ie, using the proximal and distal ports) to allow minimal contact time of the 2 agents before administration to the patient. Ideally, incompatible agents should be changed to compatible combinations when possible. Other considerations when working to minimize the risk of incompatibility are to administer medications sequentially and to flush between medications.1Relatively frequently, the pharmacist is forced to reply to a nurse’s request for compatibility information with either “there are no data” or “not compatible” for many of the newer agents and combinations to be used in the ICU. Despite a growing body of literature evaluating the compatibility of IV medications, we have not been able to catch up to the ever-increasing number of new IV agents approved for use in the ICU. The problem is compounded by a lack of financial incentives for drug manufacturers to perform these studies. Often, we are limited to textbooks as tertiary references (published by independent researchers) for this information; however, these texts tend to lack data from the most recently agents approved by the Food and Drug Administration.Additional problems are associated with a lack of accurate information on all conceivable combinations of agents to be used, often forcing nurses into positions in which clinical judgment and risk/benefit assessments must be made to determine if drugs are to be infused concurrently and how to minimize adverse outcomes. This discussion seeks to identify IV medication resources, define compatibility and incompatibility, as well as outline the available information on the IV infusions most commonly used in the ICU.There are relatively limited comprehensive resources available evaluating IV medication compatibilities. Most of the primary literature is limited to 5 or fewer agents being evaluated. These original studies are sought when other more comprehensive resources (typically tertiary references) have not been updated with these data. The most commonly used tertiary reference among pharmacists and pharmacy departments is the Handbook on Injectable Drugs. This text tabulates the results of published reports from primary studies. The tables provide information regarding compatibility of a drug in various solutions, 2 or more drugs in various solutions, 2 or more drugs in the same syringe together, and simulated or actual injection into Y-sites of administration sets. It is this last category of data (situations in which drugs are administered concurrently via a Y-site) that are most relevant to nursing practice and actual drug administration at the bedside.Additional resources include online tools such as MicroMedex (Thomson Scientific and Healthcare), which compiles data from the Handbook on Injectable Drugs. Such products such as these are in use at many institutions throughout the country and have increased the level of accessibility to compatibility information (24 hours a day, 7 days a week) from any patient care area with Internet access (available to pharmacy, nursing, and medical staff ).The Handbook on Injectable Drugs has successfully standardized the definition of compatibility and incompatibility. An agent is considered compatible if it meets the following criteria:The designation of incompatible is made when either or both of the preceding criteria are not met. The designation of incompatible is not limited to simply the presence of a visible precipitation, which is a common misconception; many instances of incompatibility are not evident to the naked eye, despite resulting in chemical changes and overall loss of pharmacologic effect.2The TableT1 provides an outline of the IV compatibility data available as of May 2007 for many of the most commonly used IV agents in the ICU. In addition to compatible (denoted as “Y”) and incompatible (denoted as “N”), some studies have provided variable results (both compatability and incompatibility demonstrated—denoted as “!”). In other studies, uncertain results (denoted as “??”) have been documented because they do not fit into the standardized definitions previously described.The process of compiling these data is not straight-forward or easy. In addition to potentially conflicting information from compatibility studies, many of the published articles have provided only partial evaluations, not looking at all aspects of the drug’s stability and compatibility. Therefore, some caution must be used in evaluating individual compatibility studies and the data should never replace good clinical decision making.In closing, the data regarding IV medication compatibility are not always clear. It is important to use available resources to provide more clarity on the compatibility issues. Drug decomposition (lack of potency) is a threat to the efficacy of medications along with visible precipitation, color change, and haziness. In these instances of uncertainty or variable results, it is prudent to weigh risk and benefit of the medication and use professional judgment. When compatibility is called into question, it is important to evaluate the catheter’s patency, infusion site, vessel, as well as pharmacologic response.