Overview
To prevent harm resulting from anesthesia care and to continuously improve patient safety, active effort is needed to manage risk. The concept of risk management (RM) is widely applied in many domains, including health care, and especially in anesthesia. Successful RM is composed of several elements, beginning with the identification of problems that should be addressed to avoid poor outcomes and followed by the implementation of an overall strategy with appropriate tactics to minimize the opportunities for failures and their ensuing accidents. Because adverse outcomes will still occur despite the best intentions and efforts, a process is needed to appropriately respond so that the correct course is pursued for the patient, providers, organization, and even for the insurer. The general principles of RM are applicable to the spectrum of causes of poor outcomes. This chapter focuses on how these principles can be applied specifically to problems to which anesthesia equipment may contribute. Problems and circumstances that lead to adverse outcomes are discussed, and a set of processes that can constitute an RM strategy are provided. RM has elements that involve medicolegal processes and concerns.
Elements of Risk Management in Anesthesia
RM is an established discipline with professional organizations, such as the American Society for Healthcare; in addition, there are RM meetings, periodicals, and textbooks. The terms frequently used in this discipline are summarized in Table 33-1 . Traditionally and even currently, the emphasis has been on managing risk for the primary purpose of avoiding financial loss. More recently, it has been recognized that financial losses can best be prevented by avoiding problems before they result in accidents and potential financial loss and that RM is intimately tied to patient safety. Formal processes have been developed in high-technology industries such as nuclear power, aviation, aerospace, and the chemical industry. Probability risk assessment (PRA), failure mode effect analysis (FMEA), and other quantitative and qualitative techniques are applied to estimate risk and plan for reaching “acceptable” risk levels. Such formal approaches have been less common in health care, but they are increasingly being adopted. Management of the risk associated with anesthesia equipment, especially for the clinician or administrator confronted with purchasing and process decisions, must often rely on more intuitive and qualitative assessments to judge the relative risks and benefits. Even in the absence of robust quantitative data, the general principles of RM are the same: defining potential problems, estimating the likelihood of occurrence, weighing the relative benefits of expenditure of available resources, applying the solutions, and monitoring how well the solutions have been applied. Perhaps the greatest problem with management of risk—especially for the rare, catastrophic events that are so devastating to all parties—is that it is virtually impossible to know whether the approach has been effective as a result of the absence of major problems, such as large or even many smaller malpractice claims. This is especially so for equipment, because such major events are relatively rarer than for other types of anesthesia-associated adverse outcomes.
| Adverse event | An injury resulting from a medical intervention (i.e., not due to the underlying medical condition of the patient). |
| Error | Failure of a planned action to be completed as intended or the use of a wrong plan to achieve an aim; not all errors result in injury. In an effort to thoroughly consider all of the relevant issues related to medical errors, the Quality Interagency Coordination Task Force report expanded the Institute of Medicine’s definition to read as follows: “An error is defined as the failure of a planned action to be completed as intended, or the use of a wrong plan to achieve an aim. Errors can include problems in practice, products, procedures, and systems.” |
| Human factor | The study of relationships among human beings, the environments in which they live and work, and the tools they use. |
| Preventable adverse event | An adverse event that was attributable to a medical error. Negligent adverse events represent a subset of preventable adverse events that satisfy legal criteria used in determining negligence, whether the care provided failed to meet the standard of care reasonably expected of an average physician qualified to take care of the patient in question. |
| Safety | Freedom from accidental injury. |
| System | A set of interdependent elements working to achieve a common aim. The elements may be both human and nonhuman (e.g., equipment, technologies). |
| Types of failure | Errors of execution are those in which the correct action does not proceed as intended; errors of planning are those in which the original intended action is not correct. |
Nature of Risk Associated with Anesthesia Equipment
The study of anesthesia mishaps provides insight into their causes and leads to interventions that should decrease their occurrences. Greater attention to improving patient safety and the introduction of new technology is believed to be associated with a declining trend in the overall incidence of anesthesia mishaps and probably also those associated with the use of anesthesia gas delivery equipment. Nevertheless, adverse outcomes related to equipment failure and/or misuse persist, and the results are often severe. In fact, the inherent rarity of serious complications from anesthesia likely creates an additional hazard: most anesthesiologists are not well experienced in responding to them. Studies of anesthesia practice have yielded valuable data that quantify the frequent causes of errors and have provided insight into the complex environment in which they occur.
Anesthesia is delivered in a complex, dynamic environment that involves the interactions of a surgical insult with unpredictable physiology, numerous pharmacologic interventions, and the use of multiple electromechanical devices. The system involves the interactions of numerous physicians, nurses, and ancillary personnel influenced by a “host of administrative, political, and cultural factors.” In this environment, deviations or “incidents” arise frequently, occurring spontaneously from the patient’s disease (e.g., hypertension), from planned interventions, (e.g., disconnecting the breathing circuit to suction the tracheal tube), or as the result of human error or equipment failure. The majority of these incidents or “near misses” have little or no impact on patient outcome. Events that could or did lead to an undesirable outcome have been termed “critical incidents.” When an event does lead to an undesirable outcome, it is referred to as an “adverse event.”
The chain of events associated with accident evolution has been studied extensively in other domains in which RM is commonly practiced. Many of the insights gained are equally applicable to prevention of anesthesia accidents. One more modern concept introduced into accident understanding and prevention in health care and anesthesia specifically is that errors and failures do not stand alone; rather they are elements embedded within a larger system, of which equipment forms one of several categories of latent risk factors for adverse events ( Table 33-2 ). It is now widely accepted that human error must be thought of in this context, that the operator is rarely the primary “fault.” For that matter, neither is the technology ever the sole “fault” or cause of an adverse outcome. The science of patient safety has embraced these ideas, which are critical for establishing measures to avoid adverse outcomes associated with equipment.
| Latent Risk Factor | Issues |
|---|---|
| Equipment, design, and maintenance | Availability, functioning, standardization design, and maintenance of machines |
| Staffing | Adequate staffing, skills |
| Communication | Work-directed communication, openness, interrelation, atmosphere |
| Training | Training for machines, procedures, team training |
| Teamwork and team training | Team performance |
| Procedures | Presence of protocols, adherence to protocols |
| Situational awareness | Awareness of present situation, own tasks, and future developments |
| Incompatible goals | Balance between goals and safety |
| Planning and organization | Process of care |
| Housekeeping | Hygiene |
Incidence and Characteristics of Adverse Equipment Events
Sources
Important sources from the English language literature that serve to define risk associated with the use of anesthetic equipment include the ASA Closed Claims Project (CCP); seven anonymous reporting systems in Australia (the Australian Incident Monitoring Study [AIMS]), Britain (National Patient Safety Agency adverse events reporting), and France (French Health Ministry’s national registry of incidents) ; prospectively collected institutional quality data ; retrospective critical incident surveys ; and case reports. Methodological challenges exist to prospectively investigate adverse anesthetic events related to equipment, foremost of which is the rarity of occurrence. Additional challenges in investigating this topic include heterogeneity in research aim and design, varied definitions used to characterize adverse events, and the subjective evaluation of these incidents. The sum of this body of literature forms a representative picture of adverse events related to anesthetic equipment and can help form strategies for their prevention.
The CCP is an evolving database on more than 9500 adverse anesthetic events with data provided by numerous malpractice insurers in the United States to physicians for review and evaluation. The database contains 150 details about each claim, ranging from objective items, such as age of the patient and monitors used, to judgments about causes of anesthetic mishaps. The AIMS is a coordinated anonymous reporting system of critical incidents by anesthesiologists from 90 Australian and New Zealand hospitals and practices. The first 2000 reports formed the basis of several studies that have reviewed subsets of adverse events in anesthesia practice, including anesthetic equipment failure. No subsequent report has been published specifically analyzing anesthetic equipment from the AIMS database. The CCP and AIMS databases provide some of the largest and most published collections of significant anesthetic events from which to glean information about the occurrence of problems possibly associated with accidents. However, because the number of cases represented (i.e., the denominator) is unknown, neither study provides a measure of event incidence. Anonymous reporting systems related to anesthetic safety have been reproduced in many countries, and the data are readily available online.
Incidence
The majority of adverse events in anesthetic practice are multifactorial and involve a combination of systems problems, human factors (“use error”), and actual technical failures. Isolated anesthetic equipment failures are rare and contribute to the minority of adverse events. Nonetheless, it is valuable for the clinician to understand the incidence of such events and to what degree each is associated with patient injury. Attempts made to identify the incidence of these isolated failures and compare them are limited by varied methodology (e.g., extended timeframe of event collection, definitions used by investigators). In addition, many of the landmark studies in this field are now several decades old and may not accurately represent the current risk associated with anesthetic equipment. Other investigators included in their analyses adverse events associated with intensive care unit (ICU) ventilators, infusion pumps, and anesthetic equipment not necessarily related to gas delivery equipment (e.g., tracheal tubes). Also, the nature of reporting in this field of study is more subjective than in many other clinical investigations in anesthesiology. Nonetheless, in adverse event databases, anesthetic equipment failures account for 1% to 9% of cases.
The most comprehensive reports on adverse events that specifically focused on anesthetic equipment include an analysis of the CCP database and the AIMS report. Although both of these were published in the 1990s, they still provide the most comprehensive analyses of patterns of adverse events involving anesthetic equipment. The comprehensive report on adverse events in the CCP database revealed that 2% (72 of 3791 total claims) were associated with gas delivery equipment. There was a greater representation of anesthetic equipment-related adverse outcomes in the AIMS report; 9% of the first 2000 reported adverse anesthetic events were due to what was analyzed to be “pure” equipment failure. An updated brief report of the CCP database in 2011 on the prevalence of equipment claims accounted for a smaller 1.2% (114 of 9214 total claims). From a more practical standpoint, the incidence of equipment failure has been reported in single-institution, consecutive record audits at 0.04% to 2% or 1 in 50 to 1 in 2252 general anesthetics.
It is not clear how generalizable these data are to individual anesthetic practices given the range of equipment used, audit reporting compliance, and definitions of “equipment problems.” It is also possible that clinicians may be more likely to report on equipment-related events; hence those may be overrepresented in databases that include noninjurious events. Fortunately, some of these equipment failures have led to practice improvement either through mandated removal from the market or design improvements.
In contrast to isolated equipment failure, “use error,” or what had been referred to in earlier publications as “human error,” has been reported as being responsible for the majority of adverse events and thus represents a far more significant contributor to adverse outcomes. Yet the user and technology are now understood to be intertwined. It may not be wise to label them in this way, but it still suffices for practical purposes. In addition, there is currently a deemphasis on personal blame in evaluating adverse events; rather, addressing systems problems has been deemed more fruitful in building a sustainable culture of safe health care delivery.
Characteristics of Adverse Events
It is unclear whether adverse events in anesthesia involving equipment are associated with a great severity of injury. In publications from the 1990s, equipment-related claims were more likely to be associated with serious injury or death and larger financial settlements than other anesthetic adverse outcomes that did not implicate equipment directly ( Table 33-3 ). Certainly, the use of financial settlement size is an imperfect surrogate measure of outcome severity, and it is possible that some equipment-related claims were settled out of court by a manufacturer and were not represented in the CCP database.
| Equipment Group | Death | Brain Damage | Awareness | Recovery Delayed | Tracheostomy Scar | Pneumothorax |
|---|---|---|---|---|---|---|
| Breathing circuit (n = 28) | 10 | 10 | 1 | 5 | 1 | 1 |
| Vaporizer (n = 15) | 7 | 3 | 5 | 0 | 0 | 0 |
| Ventilator (n = 12) | 7 | 5 | 0 | 0 | 0 | 0 |
| Supply tanks or lines (n = 8) | 6 | 2 | 0 | 0 | 0 | 0 |
| Anesthesia machine | 3 | 0 | 1 | 0 | 1 | 0 |
| Supplemental O 2 tubing (n = 4) | 1 | 1 | 0 | 0 | 0 | 2 |
| Total (n = 72) | 34 (47%) | 21 (29%) | 7 (10%) | 5 (7%) | 2 (3%) | 3 (4%) |
The AIMS report identified that the leading sources of equipment problems included unidirectional valves, ventilators, anesthesia machines, breathing circuits, gas supplies, and electricity. More recently, the CCP database added only 39 claims related to anesthesia gas delivery equipment from 1990 to 2011. These include 10 problems related to breathing circuits, 13 with vaporizers, 7 with the anesthesia machine itself, 5 with ventilators, and 4 described as “supplemental oxygen line events.” The management of many specific hazards and failures associated with anesthesia equipment are described in Chapter 30 .
Anesthesia gas delivery is complex, with multiple connections and moving parts that would make it easy to suspect that equipment failure would play a prominent role in adverse events, but misuse of equipment appears to be more common than equipment failure per se, emphasizing the role of use error in equipment-related critical incidents and adverse outcomes ( Table 33-4 ). Breathing circuits are an excellent example of this phenomenon; simple misconnection or disconnection of breathing circuits was the initiating event in a large proportion of cases. More importantly, perhaps, this subset of adverse event type made the largest single contribution to injury when compiled over the entire course of the CCP ( Table 33-5 ). It seems intuitive that the use of capnography, breathing circuit pressure, and pulse oximetry monitoring would have led to a reduction in patient injury related to those events over time, but there has not been convincing evidence to support that assertion.
| Equipment Group | Initiating Event | No. of Claims | % (n = 72) |
|---|---|---|---|
| Breathing circuit (n = 28) | Misconnect | 14 | 19 |
| Disconnect | 11 | 15 | |
| Leak | 1 | 1 | |
| Valve failure | 1 | 1 | |
| CO 2 canister defect | 1 | 1 | |
| Vaporizer (n = 15) | Valve failure | 5 | 7 |
| Leak | 2 | 3 | |
| Wrong dial/setting | 2 | 3 | |
| Tipped over | 1 | 1 | |
| Hooked up backwards | 1 | 1 | |
| Not turned on | 1 | 1 | |
| Knob turned inadvertently | 1 | 1 | |
| Uncertain | 2 | 3 | |
| Ventilator (n = 12) | Not turned on | 3 | 4 |
| Valve misinstalled | 2 | 3 | |
| Wrong ventilator chosen | 1 | 1 | |
| Valve failure | 1 | 1 | |
| Wrong setting | 1 | 1 | |
| Uncertain | 4 | 6 | |
| Supply tanks or lines (n = 8) | Oxygen switch | 7 | 10 |
| Uncertain | 1 | 1 | |
| Anesthesia machine (n = 5) | Leak | 3 | 4 |
| Wrong knob turned | 1 | 1 | |
| Uncertain | 1 | 1 | |
| Supplemental oxygen tubing (n = 4) | Direct connection | ||
| Wall to patient | 4 | 6 |
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