Key Points
- 1.
Cardiac surgical patients are at significant risk from preventable adverse events. These events occur through human error, by either faulty decision making (diagnosis, decision for treatment) or faulty actions (failure to implement the plan correctly).
- 2.
Human error is ubiquitous and cannot be prevented or eliminated by trying harder or by eliminating the one who errs. Reduction in human error requires system changes that prevent errors from occurring or prevent errors from reaching the patient.
- 3.
Sleep deprivation and fatigue can render a person more likely to make an error. Although residents’ hours are limited, those of other physicians in the United States are not, unlike in other countries.
- 4.
Nontechnical skills such as leadership, communication, cooperation, and situational awareness are critical to patient safety, but they are rarely taught. Distractions, disruptions, noise, and alarms contribute to technical errors and increase mortality rates in cardiac surgery.
- 5.
Communication is the leading root cause of sentinel events, whether through missing information or through misunderstanding. Use of structured communication protocols reduces errors. Handoffs performed without a protocol involve significant numbers of omitted items.
- 6.
Team training reduces surgical mortality rates, but it must be done with careful preparation and with regular retraining.
- 7.
Surgical briefings that use a checklist significantly reduce surgical mortality rates. Debriefings allow teams to identify hazards and formulate improvements.
- 8.
Simulation is an effective means to teach both technical and nontechnical skills and to allow teams to train for rare but dangerous events.
- 9.
Cognitive aids should be available in every operating room to provide direction during rare crisis events (eg, malignant hyperthermia, pulseless electrical activity).
- 10.
Medication errors occur approximately in 1 in every 150 to 200 anesthetic cases. The Anesthesia Patient Safety Foundation published a set of recommendations to reduce medication errors, including standardization, use of technology such as bar codes and smart infusion pumps, having pharmacy involvement in every step of the medication process, and building a culture of safety.
Cardiac surgical patients each year become ill and die because of preventable adverse events, and they are more likely to have adverse events than other surgical patients (12.2% vs 3%), with 54% of these events considered to be preventable. These numbers may underestimate the true rate of adverse events. Despite significant attention and discussion, eradication of these preventable medical events has proved difficult, largely because medical education remains focused on technical rather than nontechnical aspects of medicine. Far more time is spent teaching anesthesia residents how to cannulate the internal jugular vein than how to communicate clearly and without error or how to understand the complexities of human error.
Patient safety involves both doing the right thing (ie, applying best practice to every situation) and doing the right thing the right way (ie, avoiding human error). Whereas most of this textbook is devoted to discussion of the right thing to do in a given circumstance, this chapter discusses both requirements for safe practice: (1) formulation of the correct plan for patient care (implementing evidence-based best practices); and (2) flawlessly carrying out the plan (preventing or correcting human error.)
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The Science of Safety
Rigorous patient safety science has improved the understanding of how errors occur and how to design safe practices, test them for efficacy, implement changes effectively, and measure the effectiveness of interventions, thus ensuring improvements.
One such comprehensive observational study of the hazards in the cardiac operating room (OR) was undertaken in the Locating Errors Through Networked Surveillance (LENS) group as part of the FOCUS (Flawless Operative Cardiac Unified Systems) project. This collaborative study involved the Society of Cardiovascular Anesthesiologists, and consisted of observations of 20 cardiac operations by a team of trained observers, including human factors engineers, anesthesiologists, and organizational psychologists. The analysis identified a myriad of hazards in the cardiac OR and detailed the complex interaction of organizational structure (lack of policies), teamwork behaviors (poor communication), system shortcomings (inadequate support requiring multiple workarounds), equipment and technologies (poorly designed and integrated), and individual failings (situational awareness). The complexity of interactions among systems, providers, and processes highlights the truth that a simple solution to patient safety is not feasible. Experts from a variety of disciplines will be required to examine every aspect of perioperative cardiac surgical care and to integrate proposed solutions.
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The Science of Safety
Rigorous patient safety science has improved the understanding of how errors occur and how to design safe practices, test them for efficacy, implement changes effectively, and measure the effectiveness of interventions, thus ensuring improvements.
One such comprehensive observational study of the hazards in the cardiac operating room (OR) was undertaken in the Locating Errors Through Networked Surveillance (LENS) group as part of the FOCUS (Flawless Operative Cardiac Unified Systems) project. This collaborative study involved the Society of Cardiovascular Anesthesiologists, and consisted of observations of 20 cardiac operations by a team of trained observers, including human factors engineers, anesthesiologists, and organizational psychologists. The analysis identified a myriad of hazards in the cardiac OR and detailed the complex interaction of organizational structure (lack of policies), teamwork behaviors (poor communication), system shortcomings (inadequate support requiring multiple workarounds), equipment and technologies (poorly designed and integrated), and individual failings (situational awareness). The complexity of interactions among systems, providers, and processes highlights the truth that a simple solution to patient safety is not feasible. Experts from a variety of disciplines will be required to examine every aspect of perioperative cardiac surgical care and to integrate proposed solutions.
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Human Error
Theory of Human Error
The universality of human error is well known and is accepted in virtually every walk of life, except perhaps medicine. Here it is expected that physicians and providers will be perfect, that the natural cognitive slips and trips and biases inherent in daily life will be overcome by the importance of the work being done and the fact that lives hang in the balance.
The elegant exploration of human error and system accidents have made it clear that patient safety in the cardiac OR will not come about by identifying and eliminating error-prone individual clinicians. In general, if the system is designed such that one person can make a given error, it is virtually guaranteed that another human will as well. For example, despite a Joint Commission Sentinel Alert in 2006 to caution care providers of the dangerous errors made possible by the use of universal connectors (Luer), hundreds of patients have died since then because intravenous fluids, pressure lines, or enteral feedings were erroneously connected to epidural catheters or arterial lines and vice versa. The appropriate system change is now being implemented, with unique connectors for intravenous, arterial, enteral feeding, and pressure tubing and neuraxial catheters established by the International Standards Organization.
Highly complex systems such as health care or the nuclear power industry are far more vulnerable, even though many of the worst events begin with a trivial misstep (eg, O-ring not tested in low temperatures in the space shuttle rocket). Even when the initiating event is a human error, correcting or preventing adverse outcomes nearly always requires a system change. Reason’s Swiss cheese model is now well accepted to demonstrate how system defenses must be in place to prevent or at least detect human errors before harm is done to patients ( Fig. 24.1 ).
Personal Readiness (Fatigue, Stress)
It has been concluded that working for more than 16 consecutive hours is unsafe for both trainees (marked increased risk of an accident while driving home) and for their patients (attention failure, serious errors, and diagnostic mistakes). After 24 hours of being awake, impairment of reaction time is comparable to that produced by a blood alcohol concentration of 0.10 g/dL. Sleep-deprived persons have a poor capacity to recognize their fatigue, thus reducing their capacity to work safely. A survey of resident physicians suggested that fatigue-related errors resulting in death or injury of a patient are not uncommon.
Fatigue has been implicated as a contributor to impaired performance, critical incidents, and errors in anesthesia. The work hours and schedules of anesthesiologists expose them to circadian disruption, with both acute and chronic sleep deprivation causing fatigue. Anesthesiologists may be more susceptible to even mild sleep deprivation compared with other medical specialties because of the vigilance required to provide safe anesthesia care.
In a well-designed, realistic, simulation-based trial, in both a sleep-deprived state and a rested state, 12 residents anesthetized a simulated patient for 4 hours. The sleep-deprived group had a trend to poorer vigilance with slower response times. The sleep-deprived group took numerically longer to detect and correct abnormal clinical events, and during the simulated anesthetic regimen, nearly one-third of the sleep-deprived group fell asleep at some stage. Similarly, when surveyed, 50% of perfusionists reported that they had performed CPB after 36 hours of being awake; 15% of surveyed perfusionists reported episodes of microsleep while performing CPB. Two-thirds reported fatigue-related errors, and 6.7% reported serious perfusion accidents related to fatigue.
Vigilance While Performing Transesophageal Echocardiograms
The introduction and subsequent widespread use of transesophageal echocardiography (TEE) brought about a major advance in cardiac surgery and anesthesia for both diagnosis and intraoperative monitoring. Anecdotally, we have noticed times when all attention in the OR is focused on the TEE machine rather than on the patient, especially with trainees. This seems to be more noticeable during the phase of learning TEE than with clinicians who are more experienced.
This area needs further investigation, but consideration should be given to where the TEE machine is placed in relation to the patient and the other monitors. The anesthesiologist working alone may be more vulnerable, given that attention can be focused on only one place at a time. Although all cardiac anesthesiologists recognize the poor ergonomics of machines and monitors, no studies define best practices.
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Teamwork and Communication
As noted earlier, preventable adverse events or human errors in the cardiac OR often are related not to technical skill or knowledge base but to cognitive, teamwork, or system failures. Skills such as communication, cooperation, and leadership are recognized to be critical components of teamwork, and deficiencies in these skills have been associated with adverse outcomes.
Communication failures, human factors, and leadership deficiencies have been found to be the top three causes underlying sentinel events in every review from The Joint Commission since 2004. In a review of litigated surgical outcomes, a communication failure among caregivers was responsible for the adverse outcome in 87% of cases. Clearly, teamwork behaviors and communication are critical to patient safety.
Disruptions, Distractions, Major and Minor Events
The cardiac OR is a highly complex setting where professionals from multiple disciplines interact with complicated and often poorly designed equipment to complete hazardous interventions—typically under significant time constraints—in patients with challenging cardiac disease and other comorbidities. Despite the apparent need for quiet concentration, distractions and disruptions rule the day. In cardiac surgical cases, door openings average 19.2/hour, 22.8/hour if prosthetic devices are involved. OR traffic, door openings, conversations, alarms, and even music can result in an excessive noise level. It is no wonder that failures of teamwork resulting in surgical flow disruptions occurred at a rate of 11.7/hour.
Team members perceive disruptions and distractions, as well as team behaviors, in discipline-specific ways. Surgeons tend to downplay disruptions and report them as having a lesser effect on performance than do nurses or trained observers. All too often, significant disruptions and distractions simply are treated as annoyances and part of the daily work. Data show, however, that technical errors and adverse patient outcomes increase as disruptions accumulate.
Equipment and Alarms
The quantity and complexity of the equipment required for cardiac operations are significant. Equipment-related problems are responsible for 10% to 12% of flow disruptions. Even though ergonomic design is known to be an important factor in patient safety, it has been suboptimal, both for OR room design and layout and for equipment design. ORs built years or decades ago are now necessarily cluttered with equipment, each device requiring electrical cords and communication tethers.
In a study of disruptions observed in 10 cardiac operations, 33% of flow disruptions were related to OR design and physical layout. A literature review regarding hazards associated with cardiac surgery identified four ways in which equipment harms the patient: (1) poor design and ergonomics; (2) poor training or negligence with use; (3) poor maintenance and upkeep; and (4) risk inherent in use of the device (eg, the risk that a TEE probe will cause esophageal injury). Medical devices and equipment typically are designed by engineers who spend little time in the environment in which the devices will be used. Even rarer is the participation of human factors engineers in the prepurchase evaluation of equipment for device-specific form and function, as well as for integration of the equipment into the existing physical layout of a typical OR. As a result, the interaction between people and technologies in the OR is suboptimal. Perhaps the most distressing single contribution to OR noise is the frequency of alarms. Alarms clearly are designed to alert to parameters outside the norm, but a typical cardiac OR has some 18 alarms, each with manufacturer-chosen visual and audio alerts. Unfortunately, the volume or tonality of the alarm has no rhyme or reason. A “not ventilating” alarm can be quiet and nearly undetectable, whereas a circuit humidifier alarm can be hair-raising. It was reported that 359 alarms occurred per cardiac operation, at a rate of 1.2/ minute. In one study, 90% of alarms were found to be false-positive events, often resulting in alarms being turned off or ignored. In a study of 731 alarm warnings, only 7% were found to be useful, and 13% were triggered by a planned intervention. As concerning as the noise and disruption are, even more concerning is the tendency to tune out the alarms or even turn off the alarms when they become too annoying, potentially resulting in a serious preventable adverse event. The Joint Commission made alarm management a goal in 2012, but true correction will require a comprehensive national (or international) approach to standardize the volume and tonality of alarms by system (eg, ventilation, cardiac) and by urgency and then to require all manufacturers to meet these standards.
Teamwork
In the highly complex world of cardiac surgery, teamwork and communication are critical to outcome. Team members (especially physicians) are poor at assessing their own teamwork and communication skill level. In multiple studies, surgeons’ and anesthesiologists’ teamwork and communication skills were rated much more highly by themselves than by nurses and perfusion staff members. In one study, surgeons rated the quality of other surgeons’ teamwork as high or very high 85% of the time, whereas nurses rated the collaboration with surgeons as high or very high only 48% of the time ( Fig. 24.2 ).
