EVALUATION OF ANAESTHESIA CARE

• Jurisdiction: Australia

The contribution of anaesthesia care to harm

Historical concepts ........................................................................................ [43.1500]

Current concepts ........................................................................................... [43.1520]

Determining if the anaesthesia care contributed to harm

Systematic investigation................................................................................ [43.1700]

The role of the autopsy

Difficulties ...................................................................................................... [43.1800]

Exceptions ..................................................................................................... [43.1820]

Types of harm ............................................................................................... [43.1840]

Death ............................................................................................................. [43.1860]

Disease ......................................................................................................... [43.1880]

Dysfunction .................................................................................................... [43.1900]

Discomfort ..................................................................................................... [43.1920]

Dissatisfaction ............................................................................................... [43.1940]

The contribution of anaesthesia care to harm

[43.1500] Historical concepts

The concept of exactly what constitutes less than an optimal anaesthetic outcome has changed with the evolution of the specialty of anaesthesia. In the 1800s, anaesthetists accepted that anaesthesia was "produced by forces ... antagonistic to those processes upon which all vital phenomena depend": Lyman (1881). As drugs and equipment improved, the concept developed "that there should be no deaths due to anaesthetics": Macintosh (1948). Some 50 years later, some anaesthetists stated that because anaesthetics were not therapeutic in themselves, then "any mishap (would be) usually regarded as an unwanted effect": Papper (1989); Lamont (1991). However, other experts recognised that suboptimal outcome rarely results from the anaesthetic alone. Review of numerous cases led Harrison to state that "the conduct of an anaesthetic is inseparable from its environment, which is a function of two complex variables: (i) the patient's disease . and (ii) the surgical operation" and interaction of these two variables is "responsible for approximately 90 per cent of peri-operative deaths": Harrison (1990). While anaesthetists might be able to influence the patient factors, improving the condition of the patient through careful pre-operative assessment and management, the same is not so for surgical factors. For example, the risk of complications increases with duration of the surgical procedure, with thresholds of about three and four hours for the development of cardiac and respiratory problems, respectively: Davies (1991). While Wolters and colleagues did not show any relationship between duration of operation and post-operative complications, they did demonstrate that patients who underwent "major" operations had a doubling of the probability of an adverse outcome: Wolters et al (1996). More recently, Lyass and colleagues studied the association between various factors and post-operative outcome in patients undergoing laparoscopic cholecystectomy. A "significantly higher postoperative morbidity rate was noted in patients who had a procedure longer than two hours" than in those patients whose procedure required less than two hours: Lyass (2000).

As a general rule, few patients will die from the anaesthetic alone and only about "10 per cent of patients will be either inconvenienced or suffer some morbidity as a result of the anaesthetic experience": Cohen et al (1986). Interestingly, this finding, that about one tenth of patients will suffer some form of adverse outcome, is very similar to the findings of many international studies of adverse events in healthcare. An adverse event can be defined as "an unintended injury or complication resulting in prolonged hospital stay, disability at the time of discharge or death and caused by healthcare management rather than by the patient's underlying disease process". A recent review of eight studies of adverse events, each using the above definition and based on at least 1000 patient records, provides a comparison of some nearly 75,000 patient records. This review showed that the "median overall incidence of in-hospital adverse events was 9.2 per cent": de Vries et al (2008).

[43.1520] Current concepts

Today, most experts would agree that problems after anaesthesia care relate to problems within the "dysfunctional system" that is the healthcare system, such as "inadequate resources, inadequately trained staff", as well as "poor communication and availability of information, poor infrastructure, bad rostering, staff shortages, and insufficient time". The "sum of these (and many others) malfunctions is a dysfunctional system": Runciman et al (2007). As a result, although perfect outcome after anaesthesia is theoretically improbable, to paraphrase Merry, no anaesthetist would ever wish to consider that "even a small proportion of (his/her patients) would be accidentally killed or seriously harmed every year": Merry (2008).

The dysfunctional system syndrome reflects the idea that more than one "contributory factor" leads to an adverse outcome and rejects the "single cause" concept. Indeed, the "reality is that there is no such thing as the cause, or primary cause or root cause": Dekker (2002). The concept that several "causal contributions" were required was first used to improve safety in many other fields, including aviation, rail, and nuclear power: Reason (1990a, 1990b, 1997) and has since spread to healthcare: Eagle et al (1992), Reason (1995, 2000).

Furthermore, results will not continue to improve without ongoing changes to the delivery of anaesthetic care and, more importantly, to the overall healthcare system. For example, changing the provider of the anaesthetic, from solo nurse practitioner or solo anaesthetist to an anaesthesia care team, may influence outcome. In one study, more patients suffered anaesthetic-related deaths when care was provided only by nurse anaesthetists than when care was given by an "anaesthesia-care team", consisting of an anaesthesiologist and a nurse anaesthetist: Bechtold (1981). Similarly, patients suffered more (11%) adverse events than predicted if care was given by a nurse anaesthetist only, and fewer (3%) if care was given by an anaesthesiologist alone, and even fewer (2%) if care was given by the "anaesthesia care team": Forrest (1980). In addition, the development of better anaesthetic agents, monitors and dedicated Recovery Rooms all have helped to make anaesthesia safer, although it is difficult to state exactly how much one improvement has made to the overall safety of anaesthetic practice. For example, if one examines the adoption of specific monitors such as pulse oximetry and end-tidal carbon dioxide monitoring, no study has been able to "prove an outcome benefit from their use": Gaba (2000). However, in general, anaesthesia now represents the model for safety improvement in healthcare: Gaba (2000); Cooper & Gaba (2002).

Two other major factors must also be remembered. The first factor is that of changing public attitudes. Before the development of anaesthesia, when the likely outcome of an operation was that of "certain death", from shock, blood loss and sepsis, patients who did survive counted themselves very fortunate. For example, Samuel Pepys would yearly celebrate the anniversary of his surviving being "cut for the stone" on 26 March 1658: Kumar & Nargund (2006). Today, with certain procedures being described as "virtually problem-free", patients are more likely to speak up about any complaint which they might have. The patient or family may complain that the problem occurred "after the anaesthetic". Physicians are not the only individuals who "mistake subsequence for consequence": Johnson (1756) and indeed, it is not always easy to differentiate events which follow and are yet unrelated (eg, post-operative coma after no intra-operative mishaps) and events which follow as a "direct result (e.g., post-operative coma after oesophageal intubation)": Davies (1986). However, anaesthetists should not be automatically blamed for a complaint as comprehensive investigation may show the importance of other contributory factors: Davies & Campbell (1990).

The second factor is that of difficulty with follow-up. Increasing use of daycare surgical facilities and earlier return of patients to the community following even major operations have limited the ability of anaesthetists to see patients post-operatively. The result is a further decrease in the opportunity for individual contact between anaesthetists and their patients. In addition, there is also the possibility that patient complaints may be under-estimated. Cohen and colleagues were able to determine that symptoms were more commonly reported when patients were interviewed than when the patients' records were reviewed. For example, headaches were reported in 5.8%-17% of patients when interviewed in contrast to 0.03%-3% in the patients' records: Cohen et al (1994). Anaesthetists have become dependent on patients making direct contact with them post-operatively if there has been an unexpected problem or upon the surgeon or family physician to relay such information. Unfortunately, communication does not always occur, although in some facilities, patients are routinely provided with questionnaires concerning their anaesthetic care and provided with telephone numbers which can be used 24 hours a day to contact an anaesthetist.

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