Quality and Patient Safety in Anesthesia Care

INTRODUCTION

Clinical anesthesia practice is often considered a model for quality and safety in medicine. In 1999 the Institute of Medicine report, “To Err Is Human” specifically identified anesthesia as “an area in which very impressive improvements in safety have been made.” Such attention to a specialty comprising approximately 5% of U.S. physicians highlights the many contributions to perioperative quality and safety generated by the specialty of anesthesia. Although unadjusted anesthesia-specific mortality has remained relatively constant for the last several decades, anesthesia providers are also able to care for increasingly older patients with more comorbidities than previously. The principles by which anesthesiologists transformed the inherently dangerous task of blunting human responses to pain and controlling vital life-support functions into a safe and almost routine occurrence are important elements of the anesthesia toolbox and should be familiar to all practicing anesthesia providers.

This chapter reviews the history of anesthesia quality and safety, identifies key approaches and strategies for improvement not only in anesthesia but also in medical specialties, and examines current and future challenges in anesthesia-related quality and safety.

DEFINITIONS: QUALITY VERSUS SAFETY

Quality and safety are related but not identical terms. Safety refers to a lack of harm and focuses on avoiding adverse events. If patient injury is avoided, then the process can be considered safe regardless of other considerations. In contrast, quality refers to the optimal performance of a task, which is multidimensional and may refer to outcome, efficiency, cost, satisfaction, or some other metric of performance in addition to avoiding injury.

It is easy to see how quality and safety do not always overlap. As an example, a process can always be made incrementally safer by installing an additional check or adding extra equipment. In anesthesia practice, for example, an anesthesia provider is arguably not fully safe unless a fiber-optic scope is present in the operating room to facilitate difficult airway management. Another extreme example is having a second (or third) anesthesia provider in the room for the entire case. Clearly, these approaches make anesthesia safer but do not necessarily represent more quality because of their poor risk/reward balance. In contrast, higher-quality care involves an “optimization” element. If a process is changed to produce faster room turnaround, better patient satisfaction, or a shorter length of stay, for example, it may represent higher quality but not necessarily better safety.

In anesthesia practice an example of a strategy that improves both quality and safety is the use of ultrasound to place central lines. By reducing the incidence of carotid puncture, ultrasound clearly improves safety. By reducing the time to successful insertion (and the number of misses), most would agree that ultrasound improves quality as well (some might argue that the additional cost of ultrasound technology mitigates that improvement). Historically, advances in anesthesia performance have affected both quality and safety.

SPECIFIC APPROACHES TO ANESTHESIA SAFETY

Learning From Experience

Because the mechanisms by which most anesthetics exert their effects are not fully understood, and because many intraoperative states (one-lung ventilation, muscle relaxation, cardiopulmonary bypass) are not part of normal human activity, a large component of anesthesia safety is derived from a history of empiric observation and experience. Driven by the goal of reducing perioperative and anesthesia-specific mortality during the early years of anesthesia practice, anesthesia providers have, over time systematically, accumulated an experience base of adverse events. Emery Rovenstine's case series of nine cardiac arrests, published in 1951, is an example of this empiric approach to safety. Although he offered no definitive solutions, practical observations (diagnosing shock versus cardiac standstill can be difficult) allowed anesthesia providers to incrementally and empirically improve anesthesia safety.

Beecher and Todd's exhaustive 1954 study of anesthesia-associated deaths in 10 centers over 4 years is another example of the empiric approach to anesthesia safety. Beecher and Todd tracked the outcomes of 599,548 anesthetics and identified 7977 deaths (more than 1 in 100) and cataloged the causes as from patient disease, surgical error, or anesthesia. Their observation that patients who received neuromuscular blocking drugs during their anesthetic were more likely to have an adverse event remains true today.

Other examples of empirically derived anesthesia safety observations include the surprising difficulty in detecting esophageal intubation (or arterial desaturation), the tendency of some anesthetics (e.g., desflurane) to trigger hypertension and tachycardia, the dangers of circuit disconnection, and the potential for delivery of a hypoxic gas mixture. In all of these the anesthesia approach has been to identify and describe the events, determine how they might occur in clinical practice, develop and test countermeasures, and disseminate the results through technical improvements or education. Taken together, observations such as these have led to reductions in anesthesia-related mortality, with current estimates ranging from 1:250,000 for healthy patients to 1:1500 for those with complex medical problems.

In addition to empiric observations about how best to prevent adverse events related to anesthesia administration, anesthesiologists have evaluated safety issues related to provider performance and how humans interact with the anesthesia delivery system. As in aviation, the human–anesthesia machine interface has been designed specifically to reduce inadvertent errors. In the same way that levers in an airplane for landing gear and flap control have a knob shaped like a wheel and a flap, for example, the knob on an anesthesia machine for oxygen gas flow is shaped differently from knobs controlling air and nitrous oxide and are always located on the right. Interestingly, some newer-generation anesthesia workstations do not have separate physical knobs for controlling individual gases; instead, they allow direct input of total gas flow and inspired oxygen concentration (also see Chapter 15 ). Similarly, the potentially dangerous delivery of hypoxic gas mixtures is prevented by “linking” the oxygen and nitrous oxide flow controls so that oxygen is always present in fresh gas flow. Nonuniversal connectors to ensure that oxygen is being delivered through the oxygen flowmeter and an oxygen analyzer to serve as a final check on the delivered gas mixture are other examples of safety mechanisms designed to avoid the inadvertent delivery of a hypoxic gas mixture.

Even though adverse events resulting from failure of mechanical ventilation or inadvertent hypoxic gas delivery have almost been eradicated in anesthesia, this process of empiric observation, event detection, risk recognition, and countermeasure development continues today. More recent examples of events recognized from empiric observation include the dangers of anemia during spine surgery (also see Chapter 32 ), hypotension in the sitting position (also see Chapter 19 ), or the role of fibrinogen in coagulopathy during maternal hemorrhage (also see Chapter 33 ).

You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here