Practice Improvement and Patient Safety in Thoracic Anesthesia: A Human Factors Perspective
Jonathan B. Mark
A 46-year-old woman was scheduled for bronchoscopy and mediastinoscopy. Following uneventful induction of general anesthesia and tracheal intubation with an 8.0 mm endotracheal tube, bronchoscopy was performed. The upper thorax and neck were then prepped for mediastinoscopy using a standard iodine/alcohol surgical preparation solution (Iodine Povacrylex [0.7% available Iodine] and Isopropyl Alcohol, 74% w/w). The endotracheal tube was moved and secured to the right side of the patient’s mouth, and the breathing circuit was secured to the side of the patient’s head. Surgical incision and dissection were assisted with a standard electrosurgical unit. Approximately 10 minutes into the procedure, the anesthesiologist detected a breathing circuit leak. She checked all external connections and determined that the endotracheal tube pilot balloon was defective. To maintain effective ventilation, the endotracheal tube position was adjusted, additional air was added to the pilot balloon, and the circuit fresh gas flow was increased from 1 to 6 L/min. When the procedure was finished and the drapes removed, the anesthesiologist noted that the surgical drape on the right side of the patient’s neck, near the endotracheal tube, was charred, and there was a 6 cm2 2nd and 3rd degree burn on the patient’s right shoulder. In retrospect, an unusual smell was noted during the case by the operating room scrub nurse, but he attributed this to the leaking anesthetic gas and did not mention this to the rest of the surgical team.
Anesthesia practice is becoming progressively safer,1 and anesthesiology is recognized as the leading medical specialty in addressing patient safety.2 Nonetheless, patients are still harmed by their anesthesia care, mostly due to preventable human error.3 Thoracic anesthesia presents special risks to patients, owing to patient comorbidities and the complexity of both the surgical and anesthesia care required. Airway and ventilation management are shared anesthesiology and surgery concerns, requiring tight coordination of care through good communication. Issues such as monitoring and positioning, airway management and ventilation—important considerations in any case requiring general anesthesia—are complicated by the nature of the thoracic surgical intervention. Patients undergoing thoracic surgery often have preexisting pulmonary disease, cardiac disease, and other major medical problems. Indeed, thoracic surgical procedures are performed on sicker patients than in the past.4 These and other factors make the management of thoracic cases particularly challenging and can contribute to the likelihood of medical errors.
One of the most widely accepted paradigms for describing system failures is the Swiss cheese model put forth by James Reason.5 When adapted to the healthcare domain, this model stipulates that medical errors resulting in patient injury are seldom caused by a single mistake and rarely are they only the result of an individual provider’s negligence. When an adverse event occurs, it is often a consequence of the alignment of “holes” in the different defensive layers (depicted as Swiss cheese slices) developed by healthcare organizations to prevent errors (Figure 2–1). These holes, or system weaknesses, arise for two reasons: active failures and latent conditions. Active failures are committed by providers and can include, for example, slips, mistakes, and procedure violations. Distraction, momentary inattention, fixation, and other contributors to active failures are natural human behaviors in a working environment that is characterized by long periods of routine activity interrupted by moments of intense stress. Latent conditions originate from decisions made by system designers, managers, and procedure writers and, unlike active failures, can be anticipated and remedied before an adverse event occurs.5,6
Figure 2–1. “Swiss cheese” model of system accidents. (From: Reason J. Human error: models and management. British Medical Journal. 2000;320(7237):768-770; Adapted to vignette.)
Latent conditions that contribute to errors in anesthesia care can be grouped into provider, teamwork, technology, and organization-level issues (Table 2–1). Providers are more likely to make mistakes when they are tired, frequently interrupted in their work, or lack experience.7 Teamwork errors often center around communication failures, which are cited in over 60% of sentinel events.8 In the operating room (OR), these errors include communication that is too late to be effective, content that is not complete or accurate, exclusion of key individuals from a discussion, and issues that are left unresolved until the point of urgency.9 Technology-related errors may stem from equipment that is poorly designed, fails to work under required clinical conditions, or creates high false alarm rates that clinicians ignore or routinely silence.10 Lastly, organizational issues such as cost cutting, regulation, fear of litigation, and production pressure are additional latent conditions that can increase error rates and compromise patient care. For example, placement of a thoracic epidural catheter may improve perioperative pain control and reduce pulmonary complications, but providers may feel pressured to avoid placing catheters for thoracic surgical patients in order to maintain high patient turnover or to reduce expenses. Decisions made at the organizational level can also affect provider, teamwork, and technology issues. Over-scheduling providers, implicitly discouraging preoperative OR team briefings to reduce turnover time, purchasing medical equipment without considering its usability, and many other management decisions may contribute to errors in the perioperative setting and compromise the safety of the OR environment.
Table 2–1. Examples of Latent Conditions in Healthcare Systems that Can Contribute to Errors in Anesthesia Care
In most healthcare organizations, rather than focusing on system changes to reduce latent errors, there is a disproportionate emphasis on prevention of active failures committed by individual care providers. In an effort to prevent these failures from recurring, management responses may include sanctions, exhortations, stricter procedures, training, and similar interventions. These measures are onlyappropriate, however, if the providers who committed the errors are particularly error-prone, inexperienced, undermotivated, or ill trained. Since this is rarely the case in anesthesia practice, efforts and resources should be directed at preventing latent conditions rather than active failures.6
A human factors approach to patient safety involves addressing all levels of latent conditions in order to reduce the likelihood of medical errors. Human factors engineering is the application of a body of knowledge about human capabilities and limitations to the design of tools, machines, systems, tasks, jobs, and environments for safe, comfortable, and effective human use.11 For example, an understanding of human information processing strengths and weaknesses can be applied to health information technology design. Tasks at which humans excel, such as decision making or noticing changes in patterns, can be allocated to clinical users, while tasks for which computers are better designed, such as making rapid calculations or filtering data streams, can be automated, thereby leaving clinicians more time to devote to their patient care tasks. In this chapter, we will discuss patient safety topics that are relevant to thoracic anesthesia (and anesthesia in general) and human factors tools that can be used to address them.
PROSPECTIVE MEMORY ENHANCEMENT: CHECKLISTS, GUIDELINES, PROTOCOLS, AND COGNITIVE AIDS
The term prospective memory refers to the human ability to remember to perform an intended action following some delay. Deferred tasks can be classified as event-based or time-based. Event-based tasks are to be executed when a certain external event occurs (eg, “If high peak inspiratory pressure develops, check the position of the double lumen tube.”). Time-based tasks are to be executed at a certain time (eg, “Check CK… at 6-hour intervals until returning to normal.”)12 and are more difficult to recall, since no environmental cue exists to prompt task execution.13,14 Failures of prospective memory may be the most common form of human fallibility.15 In thoracic anesthesia, prospective memory errors may result from the demanding work environment, which often requires dynamic multitasking and is fraught with interruptions, delays, and other distractions. At least 12% of critical anesthesia incidents may be attributable to factors associated with inadvertent neglect of future tasks, including haste, distractions, and failure to follow personal routine or institutional practice.7,16
In addition to individual efforts (eg, anticipating triggering cues or avoiding busy conditions and interruptions), experts recommend the use of external prompts such as checklists to assist in the recall of delayed intentions.15,17 In addition to their utility as reminders, checklists are useful in standardizing clinical practice, allowing providers to deliver evidence-based care consistently.18 They can also assist providers when confronted by novel, urgent, or rare situations. Checklists have been shown to reduce prospective memory errors, decrease risk, and improve outcomes in safety-critical industries such as aviation and manufacturing.19 Their more widespread use has been recommended in healthcare,20 and several researchers have begun to explore their utility in anesthesiology.
Checklists have been developed for several perioperative tasks. In an attempt to prevent incomplete checkouts of anesthesia equipment, which have been shown to lead to anesthetic mishaps,21 the Food and Drug Administration developed a comprehensive anesthesia equipment checklist. However, this checklist was neither well-understood nor reliably utilized by anesthesia providers22 and did not promote better checks than when providers used their own checkout methods.23 More recently, the American Society of Anesthesiologists published a template for developing an equipment checklist tailored to individual anesthesia machines and practice settings.22 Although it has not been evaluated formally, it is hoped that the ability to adapt it to each institution’s requirements will make it useful and effective.
Standardized preoperative briefings and OR “time outs” have been mandated by the Joint Commission as part of its Universal Protocol.24 Time outs are to be conducted before each surgical procedure to verify that the correct patient, positioning, surgical site, and procedure are identified. A Surgical Safety Checklist developed by the World Health Organization25 (Figure 2–2) has been shown to reduce patient morbidity and mortality worldwide.26 The checklist begins during a preoperative team briefing (Sign In) conducted before induction of anesthesia and includes verification of patient identity, allergies, surgical site, and needed supplies. Before incision, a formal Time Out is used to introduce team members, confirm patient identity, operative site, and procedure correctness, review anesthesia, surgery, and nursing concerns, and verify that prophylactic antibiotics have been given and relevant imaging displayed. Finally, after surgery is completed, the nurse leads a debriefing or Sign Out and confirms the name of the surgical procedure performed, instrument and sponge counts, correct specimen labeling, and equipment or other problems that need to be followed up. The Sign Out concludes with a team discussion of patient recovery and management concerns.
Figure 2–2. World Health Organization Surgical Safety Checklist. (Reproduced with permission from World Health Organization. Surgical Safety Checklist 2008;http://www.who.int/entity/patientsafety/safesurgery/tools_resources/SSSL_
Checklist_finalJun08.pdf. Accessed August 27, 2009.)
In addition to checklists, other memory aids that have been advocated to improve patient safety include the use of written treatment algorithms, or cognitive aids, that may be very useful for crisis management. It has been estimated that 5% of anesthesia cases develop into critical situations.27 During a crisis, the anesthesia provider must perform multiple complex, dynamic tasks involving high workload and information load, such as hypothesizing the source of the problem, testing different assumptions, monitoring changes in patient state, administering drugs, ventilating the patient, communicating with the surgical staff, etc. Given this task complexity, suboptimal communication and teamwork, and often coexisting fatigue and stress, it is not surprising that errors occur during the management of these incidents. Algorithms have been created to improve decision making and reduce errors during these critical events,27-29 and they include guidelines for managing many different events, ranging from malignant hyperthermia to OR fires.
Although there are only a few treatment algorithms that have been developed specifically for crisis management during thoracic anesthesia care, other general anesthesia crisis management algorithms are highly relevant. One example of an evidence-based thoracic anesthesia algorithm focuses on determining the need for intensive care unit (ICU) admission following lung resection.30 Several general crisis management protocols that are particularly relevant for thoracic anesthesia include those developed for treating high-peak inspiratory pressure or hypoxemia during mechanical ventilation27,29 (see Table 2–2). Although checklists used for healthcare in general19 and in anesthesiology in particular31 have been shown to improve clinical outcomes, these memory aids have not yet found the same acceptance in medicine that they have in other high-risk industries, such as aviation.19 An opportunity exists for developing specific checklists, algorithms, and cognitive aids that are unique to the practice of thoracic anesthesia. For instance, management of hypoxemia or high peak inspiratory pressure arising during one-lung ventilation (OLV) can be summarized in a checklist useful for troubleshooting these common thoracic anesthesia problems. This complex domain would profit from systematic protocol development and evaluation for both routine care and crisis management.
Table 2–2. Hypoxemia Treatment Cognitive Aid Developed by the VA National Center for Patient Safety.
Despite evidence of the benefits of checklists, their implementation in healthcare has been limited19,32,33 due to both operational and cultural barriers. It is difficult to standardize medical procedures because of variations in patient physiology, individual practice preferences, and institutional policies. Care providers often resist the adoption of checklists for various reasons, such as concern that clinical innovation may be stifled, their role as decision makers will be reduced,32 or that using a checklist would be perceived as a show of weakness or lack of professional expertise.33,34 In addition, the checklist itself may be unclear or difficult to apply.34 For these reasons, it is important to assess the utility and acceptance of checklists before they are implemented in the OR.
There is growing appreciation for the importance of sound communication skills between care providers in healthcare. Good teamwork and communication are essential for delivering high-quality patient care. Communication errors are a major root cause of patient harm,8 while effective team communication skills have been shown to increase staff35 and patient36 satisfaction and to improve clinical outcomes.37,38 In the OR, approximately 30% of procedurally relevant exchanges can be defined as communication failures.9 Improving information transmission between team members can prevent adverse events associated with anesthesia administration.7
There are several communication tools and team skills, which when applied together, can establish a common mental model among team members and create an environment that empowers providers to speak up when they have safety concerns35 (Table 2–3). The first is leadership: team leaders, whether designated or impromptu, play an important role in promoting good teamwork by organizing teams, articulating goals clearly, making decisions based on team members’ input, and making members feel safe challenging their superiors when clinically necessary. Leaders also facilitate briefs (planning sessions), debriefs (process improvement discussions), and huddles (ad hoc problem-solving meetings), three important tools to ensure that all team members are “on the same page”39 (Table 2–4). In thoracic procedures, teams can be large and diverse, including members from anesthesia, surgery, intensive care, nursing, pathology, laboratory, pharmacy, blood bank, and other disciplines. Team members often have varying levels of training and experience, team composition may change frequently, and different leaders may be responsible during different phases of the perioperative period. Enabling good teamwork can be more challenging in these circumstances than when coordinating small teams with consistent team members.40
Table 2–3. Teamwork and Communication Tools and Skills
Table 2–4. Important Elements of Team Briefs, Huddles, and Debriefs
Another skill that characterizes high-performing teams is the establishment of a shared mental model.41 Teams that share a common mental model understand the current system state, can interpret what it means for team members, and are able to deduce their future actions and expectations.41 Individuals that have good situation awareness, acquired through situation monitoring (actively observing the situation and environment) and cross monitoring (monitoring other team members in order to support their work and prevent errors), facilitate the creation of a shared mental model.39 It is critical for anesthesia providers in thoracic cases to maintain situation awareness when the patient’s airway and breathing are shared with the surgical team. Understanding the surgeon’s current and planned actions can help the anesthesia provider anticipate changes in patient ventilation and react appropriately. A shared mental model is also important when positioning the patient. Correct positioning to avoid patient injury is particularly difficult and time-consuming in thoracic procedures. Inefficiency can be prevented and safety achieved through preoperative discussions between surgeons, anesthesiologists, and nurses during the Sign In or preoperative briefing.9
Mutual support is also an essential component of good teamwork. Mutual support includes offering task assistance to colleagues and advocating for the patient. Advocacy is invoked when a team member’s viewpoint regarding patient care does not coincide with that of the decision maker. In this situation, the team member should assert his or her position in a firm, respectful manner. If ignored, the team member should voice concern at least twice and, if the outcome is still not acceptable, speak with a person higher up in the chain of command.39 Assertion is likely the most important—and most difficult—team skill to apply. Its goal is to prevent medical errors from occurring, but assertion requires a care provider to challenge another provider, usually his or her superior, in a culture that has traditionally been very hierarchical and discouraging of such practice. Therefore, it is important to first set up a supportive environment, one that “flattens” hierarchy, creates familiarity, and makes providers feel safe to speak up.35 In contrast to surgeons, anesthesia providers and nurses are not as comfortable intervening when they have concerns about patient status.42,43 However, anesthesia providers are perceived as “patient advocates,” “diplomats,” and “diffusers” by nursing, surgery and by themselves,44 and in this capacity they can help create a supportive climate that encourages equality and openness in the OR.
The high-stakes, high-reliability domain of commercial aviation has shown that the adoption of standardized communication tools is a very effective strategy for improving teamwork and reducing risk.35Structured communication can be useful in many clinical situations. Here we’ll mention SBAR, check-back, and handoffs as examples. SBAR is a framework for effectively relaying information about a patient during briefings, phone calls, or any situation that calls for a concise description of a patient’s condition. SBAR stands for Situation (what is going on with the patient?), Background (what is the clinical context?), Assessment (what do I think the problem is?), and Recommendation (what would I do to correct it?).
Check-back is a communication loop in which the receiver of a message repeats it back to the sender and the sender verifies its correctness.39 Check-backs are valuable for transmitting crucial information such as medication doses or laboratory results. Thoracic anesthesiologists will recognize this communication loop as a vital part of the OR conversation between perfusionists, surgeons, and anesthesiologists during cardiopulmonary bypass procedures (eg, Surgeon “Go on bypass,” followed by Perfusionist “On bypass, now at full flow”).
Finally, standardizing patient handoffs can reduce errors and omissions in information transfer while improving the efficiency of the patient transfer process.45-47 Handoffs have been shown to be a high-risk, error-prone point of patient care46 (with trainees being particularly prone to communication failures in this process),46,48 and their standardization has been required by the Joint Commission.49 One method for structuring handoffs is the use of tools such as SBAR when communicating patient information. Another method involves development of protocols and checklists for specific disciplines and situations. For example, Catchpole and colleagues created a protocol for handing off pediatric cardiac surgery patients who were being transferred from OR to ICU.45 This protocol had specific roles for different providers at predefined times, such as “the anesthetist checks the equipment and that the patient is appropriately ventilated and monitored and is stable” during equipment transfer. A checklist—the information transfer aide mémoire50—was created for use by the surgeon, anesthetist, and receiving ICU team to ensure that important patient information was communicated during the handoff. Like pediatric heart surgery patients, postoperative thoracic surgical patients are in a compromised physical state, and it is essential that the receiving ICU team establish a shared mental model with the OR team through a comprehensive discussion of patient status and surgery, anesthesia, and other team member concerns. Standardizing this process can improve patient care by ensuring information completeness and accuracy.
MONITORING AND ALARMS
Anesthesia providers use many sources of information to track patient status. In addition to gathering data directly from the environment (eg, viewing the surgical procedure or observing the patient), the anesthesia provider operates the patient monitor, which displays as many as 30 distinct physiological variables,51 as well as the anesthesia machine, ventilator, infusion pumps, and record-keeping systems. Additional monitors may be required for certain procedures and patients, such as a transesophageal echocardiograph (TEE). Performing anesthesia-related tasks while monitoring the patient can be cognitively demanding. Manipulation or observation of the TEE, for example, has been shown to increase workload and adversely affect vigilance in normal working conditions.52 When patient status begins to change unexpectedly, this information-rich environment can also lead to attention overload. In these situations, the anesthetist’s decision-making and problem-solving behaviors are generally concentrated at higher levels of abstraction than the information provided by standard OR monitors. For example, the anesthesiologist will focus on entire physiological systems, rather than single measured variables that only partially map the patient’s state.53 Numbers and waveforms can only indicate that a problem exists; they do not support the anesthesia provider in diagnosing it, defining its etiology, or in making treatment decisions.
Equipment designers and purchasers often fail to consider the usability of perioperative monitoring systems and the implications of systems that lack in functionality or usability on providers’ performance.3,54 One possible outcome is clumsy automation, a poor fit between humans and machines that leads to increased cognitive workloads during critical periods.54,55 The effects of poorly designed monitors include inefficiency and frustration. Inadequate system design can also promote human error or prevent successful recovery from errors.3,56 Human factors tools such as usability testing, simulation-based training, and human-centered design can help identify and correct problems with clinical monitoring systems before they are implemented in the OR.
The anesthesia provider’s first line of defense in crisis management is the auditory alarm. Most patient monitors feature single-sensor single-indicator limit alarms, which are activated whenever a physiological variable deviates from a predefined range. There is general agreement that these threshold alarms have failed at their role of redirecting the anesthesia provider’s attention to clinically important changes in patient state.57-60 Perhaps the leading reason that alarms have proven ineffective is that the false alarm rate is substantial: in the OR, 75% of alarms are spurious, caused by patient movement, interference, or mechanical problems. Only 3% indicate actual risk to patients.57,61 Another problem is that different alarm conditions can generate similar sounds and the same condition can generate different alarms on different devices.60 Often, when the patient’s condition is deteriorating, multiple alarms go off simultaneously, increasing the anesthesia provider’s workload rather than decreasing it.54 Alarms lack context sensitivity, that is, they are not “aware” of artifacts caused by patient positioning, intubation, and other extraneous circumstances that can cause physiologic disturbances.58,60 They also cannot project the clinical urgency of the alarm-triggered condition.60 As a result of these limitations, many anesthesia providers simply disable bedside monitor alarms. In the United States, 84% of 115 anesthesiologists surveyed indicated that they sometimes turned off anesthesia alarms. The percentage of respondents who regularly turned off the alarm ranged from 12% (low inspired oxygen) to 77% (low mean blood pressure).60 In thoracic anesthesia, where the amount of monitored data is greater than in other, less complex procedures, false alarms are more common and, therefore, more disruptive. Specific stages of thoracic anesthesia, such as the transition to OLV or interruption of ventilation, are particularly prone to irrelevant alarms.
Various attempts have been made to alleviate the alarm problem in ORs, ICUs, and other care settings. Several studies evaluated the use of continuous auditory streams of physiological data, similar to the pulse oximetry tone, and of auditory icons and “earcons” to support the identification of the type and origin of changes in patient’s state.62,63 Other efforts have examined visual alarms, delivered via a head-mounted display, as a possible replacement of auditory alarms.62 Intelligent (or integrated) alarms, which synthesize multiple physiological variables to produce a single status assessment, have also been proposed.64-66 These alarms, based on artificial intelligence engines, are intended to reduce the number of low-level nuisance alarms. A similar approach uses redundant signals to identify deviations of a single physiological variable. The arterial blood pressure waveform, for example, was used as a secondary source of information to validate ECG arrhythmia alarms.67 Finally, delays have also been suggested as a simple method of reducing clinically irrelevant alarms.59 Each of these solutions is promising, but each introduces new problems to clinical monitoring which have to be addressed prior to field testing and widespread implementation.
On average, a hospital patient may be subject to at least one medication error per day, yet at least a quarter of all adverse drug events may be preventable.68 Drug-administration errors are particularly concerning in anesthesia practice, where providers administer large numbers of drugs. Drug errors are committed in as many as 1 in 133 anesthetics,69 and up to 21.7% of these errors result in patient harm (not including awareness).70 The most common medication errors are syringe swaps, ampoule labeling errors, and preparation errors (eg, morphine dilution).70
A category of wrong-drug errors that is particularly relevant to thoracic anesthesia is tubing misconnections, the cross-connection of tubes and catheters. A broad range of medical devices, which have different functions and access the body through different routes, are often outfitted with similar connectors. These interchangeable connectors can lead providers to unintentionally connect intravenous (IV) infusions to epidural lines and, conversely, epidural solutions to IV catheters.71 A fail-safe solution to this problem, the creation of different connectors for epidurals, IVs, enteral feeding tubes, dialysis catheters, etc, is not widely available or utilized. Less reliable approaches include labeling and color-coding tubes and catheters and training clinicians to trace tubes from origin to patient.71
Although similar drug names and confusing labels are commonly blamed, they are involved in relatively few perioperative medication errors. More common causes of error are performance deficits, inattention, communication failures, and failure to follow protocols.72 An observational study of anesthesia provider activities in the OR sheds some light on these findings. Its authors found the drug preparation and administration tasks to be complex, yet inefficient and error-prone. An analysis of the preparation and administration of a single bolus of IV drug identified 41 distinct steps. Drug and fluid-related tasks comprised 50% of anesthetists’ clinical activities during set-up and 20% of activities during surgery. The authors also found that searches for medications in the anesthesia cart were frequent; that the workspace was often disorganized, littered with sterile packaging, used and unused syringes, and airway equipment; that IV tubes and poles were commonly in the way; and that objects, including drug-filled syringes, were frequently dropped on the floor and retrieved (sometimes without assuring their sterility).73 What is surprising, in an environment that is so unfit for the performance of such intricate tasks as drug preparation and administration, is not that errors occur; it’s that they occur so rarely.
Several methods have been proposed for reducing the incidence of perioperative medication errors. Simple tools include increasing the legibility of drug labels, color-coding by class of drug, carrying out double checks, prefilling syringes with the most commonly used anesthetic drugs, labeling syringes, and organizing the anesthesia cart and workspace.73-76 A more sophisticated solution could include bar-code automation that speaks the name of the scanned drug out loud, verifies its correctness, and documents its use.73-75 Although no single method will prevent all medication errors from occurring, a combination of methods can reduce their likelihood.
Management of the patient’s respiratory system and the anesthesia equipment attached to it is a demanding task. The ventilation system is complex, composed of a large number of biological and equipment-related variables. There is tight coupling among processes within this system and with other physiological systems. These factors and the dynamic, uncertain, risk-laden nature of the ventilation system combine to create a challenging environment for managing respiratory events.77
A large fraction of anesthesia-related critical incidents can be attributed to airway and respiratory problems. For example, the Australian Incident Monitoring Study (AIMS) found that 16% of all anesthesia-related incidents involved ventilation problems.78 In a closed claims analysis of anesthesia cases resulting in death or permanent brain damage, 35.6% of events were associated with the respiratory system, most commonly due to difficult intubation or inadequate ventilation/oxygenation. Concurrent with the introduction and gradual adoption of pulse oximetry and capnography monitoring (recognized in 1990 and 1991, respectively, as standards for intraoperative monitoring by the American Society for Anesthesiologists) was a decrease in the proportion of respiratory-related events leading to death or brain damage.79 Although association does not prove causation, it is possible that the improved ability to monitor patient oxygenation and ventilation led to this reduction.
Respiratory concerns are intensified in thoracic procedures requiring one-lung patient ventilation, although the frequency of patient injury related to the use of one-lung anesthesia is not well-known. Hypoxemia is common in these procedures.80 Airway devices like double-lumen endotracheal tubes and bronchial blockers (BBs) are frequently misplaced or in suboptimal position for lung isolation, and can become dislodged during patient positioning and surgical manipulations.81,82 Placing these devices may increase the risk of airway trauma, and their use can be challenging for providers who have limited experience in thoracic anesthesia.81,83 In thoracic surgery, respiratory failure accounts for approximately half of the 30-day postsurgery mortality.84 Although data on respiratory events in thoracic anesthesia are not available, their incidence is likely greater than the incidence in nonthoracic cases due to the complexity of surgery and frequency of OLV.
Anesthesia providers are trained in the management of difficult airways and ventilation problems, but they receive few opportunities to practice these skills since life-threatening intraoperative airway and respiratory events are uncommon. Although periodic retraining is important to reinforce airway management skills, simulation-based training, for example, Anesthesia Crisis Resource Management, is particularly useful for augmenting airway skills with aspects of crisis management and decision making not usually taught in postgraduate and residency education.85 In certain circumstances, checklists can be useful in resolving difficult airway issues. The evidence-based American Society of Anesthesiologists Difficult Airway Guidelines can facilitate the management of patients who are difficult to ventilate or intubate.86 A checklist for supplies to be stocked in emergency carts can prevent the occurrence of missing equipment during critical periods.
Patient Safety Issues Raised in Case Vignette
1. Standard fire precautions (control of oxidizers [oxygen] and fuel [alcohol]) whenever an ignition source (electrosurgical unit) is used during surgery.
2. Operating room Time Out to include fire precautions and assurance that surgical preparation is dry prior to incision and use of electrosurgical unit.
3. Team roles, communication, and assertion, including need for all team members to “speak up” when they detect problems. This includes anesthesia staff that detected a circuit leak and needed to increase fresh gas oxygen flow, and nursing staff that detected something unusual during the case but failed to mention this to other staff members.
Active failure—an unsafe act committed by care providers at the “sharp end” of the system, that is, providers whose actions can have immediate, adverse consequences.
Advocacy—arguing in favor of the patient when a team member’s viewpoint does not coincide with that of the decision maker.
Assertion—requesting corrective action from a team member in a firm, clear, respectful, nonthreatening manner.
Check-back—a communication loop in which a sender initiates a message, the receiver provides feedback confirmation, and the sender verifies that the message was received.
Checklist—a list of action items or criteria arranged in a systematic manner, allowing the user to record the presence/absence of the individual items listed to ensure that all are considered or completed. Checklists lie somewhere in between an informal cognitive aid, such as a post-it note, and a protocol, which typically entails mandatory items for completion to lead the user to a predetermined outcome.
Deferred task—a task to be performed following a delay, that is, a task that requires prospective memory. Deferred tasks can be classified as event-based or time-based. Event-based tasks are to be executed when a certain external event occurs, while time-based tasks are to be executed at a certain time.
Handoff—the transfer of information (along with authority and responsibility) during transitions in care. Handoffs should include an opportunity to ask questions, clarify, and confirm information.
Human factors engineering—a field which is involved in conducting research regarding human psychological, social, physical, and biological characteristics, and in applying that information with respect to the design, operation, or use of products or systems for optimizing human performance, health, safety, and/or habitability.87
Latent condition—a condition that is created as a result of decisions made in management positions. Their consequences may lie dormant for a long time, only becoming evident when they combine with active failures and local triggering factors to create a medical error.
Leadership—providing guidance and direction within a team framework. An effective leader organizes teams, articulates goals clearly, makes decisions based on team members’ input, empowers members to challenge their superiors when clinically necessary, and is skillful at conflict resolution.
Mistake—a failure of intention: the plan is inadequate, though its execution may be carried out as planned.
Mutual support—the support that team members render each other to protect from work overload.
Prospective memory—the ability of humans to remember intentions to perform actions after a delay, such as remembering to purchase milk on the way home.88
SBAR—situation, background, assessment, recommendation. A tool for effectively and concisely communicating about patients by stating what is going on with the patient, the clinical context, what the problem is, and how it can be corrected.
Shared mental model—the perception of, understanding of, or knowledge about a situation or process that is shared among team members through communication.
Situation awareness—the state of knowing the current conditions affecting a team’s work, such as the status of a particular event or of the team’s patients.
Slip—a failure of execution: the plan is adequate, but its execution is not as intended. A slip is caused by attention failure.
Violation—a deviation from safe operating practices, procedures, standards, or rules. Deliberate violations differ from errors in that they are associated with motivational problems.
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