Chapter Outline
Systems Approach to Infusion Technology 236
Standardization 237
Hardware 237
Software 237
Connectivity 237
Peopleware 238
Infusion Pump History: From “Stand-Alone Pumps” to “Intelligent Infusion Devices” 238
Technology Matched to Functional Clinical Requirements 240
Technology Moves to Site of Care 241
Learning Environment and Institutional Self-Assessment 241
Implications for Anesthesia and Anesthesiology 242
A “Toolkit” Of Questions To Assess A Provider Organization’s IV Medication Safety System 245
The purpose of this chapter is to provide a framework for anesthesiology clinicians to understand drug infusion technology devices and their safe use . Intravenous infusion of fluids and drugs during the practice of anesthesia has commonly been viewed as mundane and straightforward. In reality, a well-constructed integrated system is required to provide a seamless transition from the clinician’s intent, to the safe and effective administration of drugs and fluids into the patient, as the patient moves through the process of care in multiple care settings. The history of how this systems approach to drug infusion technology has evolved since the simple “analog” infusion devices of the 1970s is briefly detailed.
In this chapter we will describe an approach and the thoughts behind an integrated system for intravenous fluid and drug delivery and the implications of such a system to a practicing anesthesiologist. Infusion pumps are best viewed not just as isolated devices, but within an overall context: a provider organization’s comprehensive, end-to-end system of safe IV medication delivery in multiple care settings (operating room, critical care, pediatrics, pain management, labor, and delivery). Infusion pumps are probably the most ubiquitous medical devices in the patient care setting, and have become a critical part of anesthesia practice. With the emergence of the new generation of modern “smart” infusion pumps, many safety features have been added to decrease adverse events and improve patient safety. Infusion pumps are used for administering bolus, continuous or long-term medication and fluids, ranging from anesthesia to pain management and enteral feeding.
Despite the increasing sophistication of infusion devices, users must recognize their own responsibilities as part of a safety assurance system . All devices have distinctive risks and failure modes that can be triggered in specific situations. Comprehensive training of users must include enumeration of risks, and how to recognize and respond to failure modes. Some risks and failure modes can be mitigated by application of technology ; the remaining risks require mitigation by user education .
Systems Approach to Infusion Technology
Infusion technology must be seen as a component of an integrated system, not as a collection of “stand-alone” devices. Drug infusion pumps are but one element of a safety assurance system for IV drug delivery in a particular healthcare provider organization. In many healthcare provider organizations, a key objective of a safe IV medication system is a seamless digital pathway from clinician order or intent, to the patient vein . Infusion system functional requirements and capabilities must be viewed in light of two key considerations: (1) patient safety and (2) efficacy in a particular environment of use (patients, therapies, caregivers, support systems) over the life cycle of a device within the organization.
A safe IV medication delivery system is a combination of “ standardization, ” hardware , software , “ connectivity, ” user education , and “ peopleware ” integrated into a single system under a singular institutional philosophy. Each element, while important in its own right, is merely a part of a larger systems approach.
Standardization
In some quarters, standardization is a four letter word. Many clinicians view the imposition of institutional standards as just that, an imposition. In reality, most professional organizations have recognized the value of standards and the inherent reduction in risk accompanying their adoption. An ideal institutional system is one that is transportable across all care settings. Drug names, drug ordering, drug preparation and labeling, drug libraries, clinical practice, and education must be as standardized as possible. In those instances where multiple approaches are legitimate or recognized by competing professional organizations, every attempt should be made to reduce variability whenever possible. The reality is that modern institutions have many functional domains that intersect the drug supply chain and each must be integrated into a standardized framework. For example, suboptimum outcomes would be likely if clinicians were guided to order vasopressin for diabetes insipidus in units per hour in a computerized provider order entry, while infusion pump drug libraries for vasopressin for diabetes insipidus protocol offered only units per kilogram per hour as the mandatory dose rate unit, and the pharmacy provided the drug, labeled only in milligrams per milliliter.
Standardization should be viewed as an enabling process that allows institutions to apply additional technologies that would otherwise be beyond the reach of clinicians. For example, a simple bar code that supplies the drug generic name, concentration, and volume could be used to automate record keeping related to drug administration. Bar coding of drug containers would also allow for immediate recognition of the container contents by sophisticated infusion device and automatic provision of the drug library file. The value of such an approach has previously been demonstrated and is discussed below.
Another advantage of standardization is exemplified in the ability to transfer and transport patients easily and efficiently across domains within an institution. Standardized platforms such as pictured below allow critically ill patients to be transported with minimal perturbation of their ongoing treatments ( Figure 17-1 ).
Hardware
Infusion pumps, while an important component of an intravenous drug and fluid deliver system, are not stand alone devices. Infusion devices are currently available to deliver solutions and drugs from multiple containers, including syringes and IV bags. Each company producing devices provides a host of functionalities designed to meet as many institutional needs as possible. Each manufacturer provides a distinct user interface and recently unique drug library functionality. A systems approach to hardware acquisition requires a complete understanding of the tradeoffs inherent in multifunctionality devices. The complexity of the user interface, and the risk of user error, may increase as the device sophistication increases. Studies of computer-based medical devices used in critical care and operating room settings have found a variety of human-device interaction problems, such as poor or nonexistent feedback to users; complicated sequences of operation; multiple poorly distinguishable operating modes; and confusing alarms. Human factor deficiencies are important because they have been shown to increase the likelihood of errors. One approach used by institutions is to deploy an overall strategy for infusion devices that provides clinicians with the correct device for the correct functionality and reduces reliance on multifunctional devices. Additional comments on this approach are provided later in this chapter.
Software
Infusion device software consists of two basic elements. Infusion pump software converts the user’s instructions, regardless of the format, into a simple algorithm of fluid delivery, regardless of the type of infusion pump (syringe, large volume, peristaltic, etc.) In more recent years, these simple algorithms have been augmented with sophisticated drug libraries that provide the clinician with additional information at the time of drug or fluid administration. Based on institutional and local practices, these drug libraries have been shown to improve efficiency and reduce some types of errors. The drug libraries for a particular institution must initially be developed in close collaboration with end users. At the same time, there must be a standardized and transparent process for iterative changes in the libraries and their implementation. It should be obvious that the management of embedded sophisticated drug libraries requires an institutional commitment to a standard compendium of drugs, including standard container format, drug concentration, drug container labeling, and the like. The value of drug libraries is reduced without attention and ongoing reevaluation to a standardized drug compendium.
Connectivity
Drug infusion pumps now have the capability to be electronically networked together for the two-way dissemination of information, such as updated drug libraries. In a few leading institutions, wireless networks are being optimized to communicate patient-specific IV medication orders , in near real time, to drug infusion pumps (a form of autoprogramming ). In the near future (in the United States), software in drug infusion pumps will likely include algorithms to permit the administration of intravenous anesthetics using TIVA (total intravenous anesthesia) or TCI (target-controlled infusion). These goals are, however, difficult to achieve without a standardized communication platform that encompasses all relevant devices.
Peopleware
No discussion of a systems approach would be complete without comments on the need for a coordinated approach to stakeholder needs. A systematic approach requires an understanding of the roles and responsibilities of pharmacists, drug library managers, biomedical engineers, nurses, physicians, educators, and information technology specialists, and also the development of an operational team dedicated to establishing and maintaining the system approach. The team establishes, guides, monitors, and adapts the end-to-end IV medication delivery system in relation to clinical practice changes and advances in treatment paradigms.
Infusion Pump History: From “Stand-Alone Pumps” to “Intelligent Infusion Devices”
Recently, infusion pump technology has focused on improving medication safety, creating user-friendly designs, developing closed-loop drug administration systems, and facilitating complete integration of smart pumps with other medical information systems used by clinical facilities. Wireless pumps are being used by healthcare facilities transitioning to high tech healthcare information systems. These programmable “smart” pumps have dose-calculation/ error reduction software (DERS) and drug libraries. Another emerging technology is bar-coded medication administration (BCMA), which allows for point-of-care verification to make sure the right patient receives the prescribed medication.
We will now provide a very brief history of improvements to drug infusion pumps.
“Analog” Infusion Pumps
Until relatively recently (1970s through early 1990s), drug infusion pumps were stand-alone devices whose only settings were related to the flow rate and volume of a medical fluid leaving a container and proceeding to a patient through a tubing conduit. If a drug was contained within the medical fluid, this was of no concern to the manufacturer of the device, as the user interface of the device did not provide any guidance or information to assist the caregiver in making the complex calculations that relate drug concentration, units of drug delivery, (such as micrograms per kilogram per minute) with fluid flow rate.
Early “Microcomputer” Infusion Pumps
During the period from the early 1980s through the mid-1990s, infusion pumps evolved from “analog and discrete logic digital” devices using simple thumbwheel or “up/down” controls and light-emitting diode (LED) one-line displays to adjust the rate of a pumped medical fluid to “computerized” devices. These contained microprocessors, memory that could store a software application and data, larger liquid crystal display (LCD) informational displays (numbers, text, or graphical objects) that formed the basis for a user interface, and a keypad (typically with up to 20 buttons or lights in a flush-mounted configuration to permit thorough cleaning).
Some of the earliest dose-computing infusion pumps, exemplified by the Baxter AS20G and the IVAC 770, allowed a user to numerically enter the concentration (mg/mL) of drug in a fluid, the weight of a patient (in kg), and adjust not the flow rate, but rather the dose rate of the pump in clinically-relevant units (μg/kg/min or μg/min). Many of these devices were quite power-efficient, with batteries that could operate the device for 12 to 20 hours, an AC power supply mounted in a cord, and DC stepper or DC servo motors powering the lead screw of a syringe pump or the mechanism of a large volume pump.
These early microcomputerized pumps provided advanced capabilities. The Baxter AS20G and the IVAC 770 syringe pumps offered dose computation, and the Minimed Medsystem III could be customized from a PC-based editor allowing multiple “personalities” tuned to the needs and ranges of diverse care settings. Both of these features would eventually merge together with “drug libraries” to form the essential features of “smart pumps.” This era also marked the appearance and disappearance of the only true closed loop blood pressure system —the IVAC 10K “Titrator” —which married a digital servo control box, an invasive arterial pressure sensor, and a microcomputer controlled pump providing clinicians with the ability to set a target mean arterial pressure and let the control loop maintain the patient at this level automatically, by regulation of a continuous infusion of sodium nitroprusside.
Early Dose Error Reduction Systems (1992-2002)
In 1992, working under a sponsored research contract and in collaboration with Baxter Healthcare , a team at Massachusetts General Hospital (MGH) developed a prototype of a drug infusion pump with a microprocessor and 128K of system memory, capable of housing a user-customized drug library of commonly used drugs, drug concentrations, units-of-delivery, and default starting dose rates of each of 40 drugs commonly used in anesthesia and critical care. Two U.S. patents, one for an infusion pump with an electronically loadable drug library, and one for a personal computer-based toolkit for creating an electronically loadable drug library, were issued to MGH and Baxter, and nonexclusive licenses to these patents were granted to drug infusion pump manufacturers worldwide. The Baxter-MGH prototype syringe pump was called the AS40, and was marketed briefly during 1993. As sold, the pump contained a factory-supplied drug library, but no separate PC-based software toolkit (“drug library editor”) was ever created by Baxter for use with the AS40 ( Figure 17-2 ).
The first commercially available drug infusion pump with drug library editor software and a pump capable of being electronically loaded with several hundred drugs in a user-customized drug library, was a dual-channel syringe infusion pump (“Harvard 2”) sold beginning in 1997 by Harvard Clinical Technology (HCT) of Natick, Massachusetts. This pump’s drug library software was capable of storing a range of safe dose rates defined by upper and lower “limits” of safe operation of the drug. Exceeding these limits would trigger an alert to the user. The user’s response to the alert could be to override the limit, reprogram the pump to a “permitted” dose rate value, or abandon the programming of the infusion. About 1000 of these devices were implemented widely at MGH and other hospitals globally. HCT was later acquired by Alaris Medical Systems ( Figure 17-3 ).
In 2001, Alaris Medical Systems introduced a configurable, four-channel, drug infusion pump initially called the “Medley” (later renamed “Alaris System”). Over time, the Alaris System became available with five types of modules that could be mechanically engaged with a central programming/control unit, the “Patient Controller” (PC). The five modules were a large volume pump (LVP), a syringe module (SP), a patient-controlled-analgesia syringe module (PCA), a bar-code-reader module, and two physiological monitoring modules. The physiological monitoring modules had the capability of pulse oximetry and capnography. Software resident in the PC was technically capable of “pausing” an opioid infusion in response to a measured physiological value crossing a limit such as a low respiration rate or low oxygen saturation. The Carefusion Alaris System, like the HCT pump, featured a user-customizable drug library editor program, but the “dose-error-reduction-system” (DERS) capability was strongly highlighted under the name “Guardrails.” “Guardrails” consisted of not just dose limit alerts, but also the pump’s capability to store within its memory all instances of dose limit overrides and their resolution for later analysis. This component of the technology, called “CQI” (continuous quality improvement) permitted basic information and data-mining tools to be applied to the problem of IV dosing errors. For example, the CQI analytic tools could be used to provide an understanding, in a particular hospital, of the medications most frequently involved in programming errors, and in what settings they occurred, so that error-mitigation responses could be developed (usually involving changes to the drug library values, or by education of users) ( Figure 17-4 ). The features of the current generation of “smart” and “intelligent” drug infusion pumps evolved over time as a result of multiple parallel developments from various manufacturers and academic efforts. For example, in 1995, Alaris Medical Systems launched the Signature Edition single and dual channel large volume pumps. These contained a factory-installed drug library of several dozen possible drugs, a subset of which could be configured for use through the pump’s user interface. This pump did not support “limits” on a per-drug basis. In 2004, a firmware upgrade together with PC editor software became available as an option for the Signature Gold® family of products, which already possessed EPROM memory and serial communication. With this option, the pump possessed multiple user-defined “profiles” or care areas and a large user-defined library of drugs together with attributes such as units, weight or BSA dose, and limits. Years prior, about 1997, a similar software upgrade option had become available for the (now CareFusion) Alaris MSIII pump.
In October, 2002, ECRI Institute, a nonprofit organization that tests and reports on biomedical equipment, identified dose error reduction systems as a “leapfrog advance” and cautioned provider organizations to address IV medication safety by this means, and to retire older generation drug infusion pump technology.
In 2004-2005, additional manufacturers introduced drug infusion pumps with DERS, including the Hospira PlumA+ large volume pump ( Figure 17-5 ), the Medfusion/Smiths Medical Medfusion 3500 syringe pump ( Figure 17-6 ), and the SIGMA Spectrum large volume infusion pump ( Figure 17-7 ).
Drug Infusion Pumps And The U.S. Food And Drug Administration
In 2010, the U.S. Food and Drug Administration identified drug infusion pumps as a critical technology. The FDA reported an unacceptable number of recalls, incidents, and patient deaths during the 5-year period (2005-2010). An “Infusion Pump Improvement Initiative” commenced in April 2010. At the same time, the FDA put in place new guidance documents that marked the introduction of significant changes in how drug infusion pumps should be designed, tested, and assessed by the FDA before being approved for commercial sale. Changes were also being implemented with respect to sourcing and management of information about problems and adverse incidents reported by users, hospitals, and companies. The goal of increased attention to “postmarket” issues is to rapidly mitigate issues arising in the field.
Technology Matched to Functional Clinical Requirements
Many considerations pertain to the selection, use, and management of drug infusion devices. These may include cost, size, weight, ease-of-use, disposables, alarms, connectivity, precision, and range of flow rates, suitability for various medical fluids, methodology for drug recognition, method of identifying a device to a particular patient, and connectivity to a clinical information system. Provider organizations may have varying “strategic” approaches to standardized care protocols for specialty patients, such as those requiring fluid restriction , including populations of pediatric patients, and patients with various organ system failures, including (renal, hepatic, pulmonary, and neurological/neurosurgical). Choices made by provider organizations about fluid restricted patients will impact, for example, the balance of syringe pumps, large volume pumps, and other technologies across the spectrum of care settings.
There is an inherent tension between the clinician’s need to individualize intravenous treatments and an institutional desire to standardize. This tension is best addressed institutionally and in a transparent fashion. Every attempt should be made to recognize legitimate individual needs and to integrate nonstandardized devices into the mainstream. At any given point in time, the details of provider organization needs, and the functional capabilities of devices that are available commercially, will be a moving target, as technology evolves. There are several different models of device acquisition under which a provider organization may operate, with respect to choice of IV drug infusion technology . For example, in an extreme (“ad-hoc technology”) example, each care setting (such as the operating room, or a neonatal ICU) of a provider organization might be permitted to select its “own” drug infusion technology and clinical practices. Patients transitioning from one care area to another, such as from an operating room to a critical care unit, may require an infusion pump equipment exchange after arriving in the new care setting. In another example, a provider organization may standardize with a single vendor strategy for drug infusion technology. Under a single vendor strategy, clinical practices will necessarily adapt to the vendor’s offering in each given application, such as patient controlled analgesia, as the vendor’s product offerings evolve over time, in response to marketplace demands, the vendor’s business model, and/ or changes in the regulatory (FDA) agenda. In a third example, a provider organization may adopt a set of core principles that serve to inform both the evolution of clinical practice, and also the provider organization’s search for “best-of-breed” technology. These core principles may be adopted by a group or steering committee and ultimately ratified by a pharmacy and therapeutics committee. Arising out of a consensus process, they comprise a formal codification of the practice of medicine at that institution, and the basis of the assumption of liability for provision of optimum quality care. Institutions that make decisions based on core principles are likely to adopt a “best-of-breed” approach to acquisition of technology in any given domain, such as pain management, neonatal care, cancer infusion, ambulatory infusion, or total intravenous anesthesia.
Examples of core principles or issues that may form the basis for an institution’s search for best of breed technology might include conservation of administered fluid volume, cost (both capital and operating), device portability for patients on multiple infusions, standardization of packaging and labeling, standardization of concentrations, sufficient number of pumps to meet clinical need, nonproprietary tubing set disposables, ease of patient transport, cost, ease-of-use, risks, and failure modes. Once established, the institution’s consensus priorities should be used as a guide for technology acquisition and related implementation activities.
Later in the chapter we have enumerated a list of questions that a new clinician might ask at a particular institution to understand “the systems” that underlie the technology and clinical protocols in use. It should not be necessary to ask these questions if the rationale for the institution’s system technology choices is transparent and understood by all; unfortunately this is not always the case.
While not obvious to the casual observer, there is a distinct advantage to having a variety of infusion devices resident in a single institution. The rationale is that sophisticated devices require a sophisticated user interface as noted previously. In some instances, the sophisticated device is mandatory due to the complexity of the clinical circumstance and drugs administered (e.g., anesthetic drugs, cardiovascular drugs, and the like). However, not all drugs need to be administered with equally high precision or in vendor-supplied containers. Anesthetics, life-support drugs, and neonatal/infant infusions require a high level of accuracy and consistency (± 3% to 5%). Total parenteral nutrition and basic fluid administration can be given safely at a medium level of accuracy (± 10%). Intermittently administered drugs, such as the majority of antiinfectives, can be given at even lower accuracy level (± 20%). The resultant assessment of technology needs based on accuracy requirements can be used to develop realistic projections of how many devices of each type or level of accuracy will be needed in any given care setting ( Table 17-1 ).
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