What causes an error? Taking a holistic approach
The primary determinants of patient outcome have typically been centered on patient factors and performance of the surgeon.Once outcomes (usually mortality) have been correctly adjusted for patient risk factors, the remaining variance is presumed to be explained by individual surgical skill.This approach, known as the persons approach, views error as an individual failure and places responsibility on the healthcare provider. A major shortcoming with this approach is that some mishaps follow recurrent patterns and the same set of circumstances can result in similar errors, regardless of the person involved.
Other high-risk industries, including aviation, nuclear power, and oil and gas production, have shown that factors contributing to error are multiple and complex. An alternative approach to error causation is the systems approach, which views error as a consequence rather than a cause, and recognizes the complex network of systemic factors that surround the individual15. The systems approach highlights the importance of looking at the full range of factors that contribute to adverse events. This is particularly important in the field of surgery, as the OR is a highly complex environment – variations in patient anatomy, sophistication of constantly evolving high-tech equipment, constant learning of new surgical techniques, high density of data that must be processed and recorded, constant decision-making that directly affects the patient, and the need for good teamwork with all team members working together. Extending beyond the study of patient factors and evaluation of surgical performance, the systems approach acknowledges the multiple underlying factors that contribute to error – looking back at the working conditions of staff and organizational context in which the incident occurred.
While a specific event may be perceived as the “root” cause of an adverse outcome, further analysis reveals a complex sequence of events, involving a combination of organizational, situational, team, individual, task, and patient factors.
Organizational factors
Organizational factors include adequate personnel and equipment, scheduling of procedures, and substitution of usual team members with new members. An example of a staffing-related organizational factor is the “July Effect” in which patient complication rates increase and hospital efficiency decreases during the month of July because of year-end changeovers involving an influx of inexperienced first-year residents. Furthermore, studies have shown that medication-ordering error rates are higher for post-call physicians during the overnight shift; patients with serious morbidities are more likely to die in the hospital if they are admitted on a weekend versus weekday; and increased staffing appears to reduce the rate of adverse events in emergency care.
Situational factors
Situational factors describe factors within the work environment and include distractions, equipment design, and physical conditions such as lighting and temperature. Noise is a major distraction in the OR, with a reported adverse ambient noise level of 65dBA and peak levels of 120dBA to 130dBA– significantly higher than the 90dBA workplace limit established by the Occupational Safety and Health Administration. Sources that contribute to high levels of background noise include anesthesia equipment alarms, surgical instruments (suction devices, drills, cautery), irrelevant staff conversations, overhead pages and doors opening and closing. High noise levels can result in communication breakdown and impaired concentration in the OR which may influence patient outcome. Healey et al developed a rating tool to evaluate interference levels from distractions in the OR. Observations from 50 general surgical operations revealed that the highest frequency distractions were beepers, movement behind video monitors, door openings, and irrelevant conversation. Similarly, Antoniadis et al studied the distribution of intraoperative interruptions in surgical procedures, and observed that interruptions and distractions occurred an average of 9.82 times per hour in the OR. The most frequent interruptions were people entering and exiting the OR, and telephone and beeper calls. In a semi-structured interview study, OR personnel have identified equipment malfunction as a frequent distraction that has often resulted in case delays and hindered concentration. The number of personnel in the OR at a single time is another situational factor that not only distracts the working team but may also increase the risk for surgical-site infections. Koutsoumbelis et al showed that 10 or more people in the OR is a risk factor for surgical-site infection in arthrodesis patients.
Intraoperative Noise Increases Perceived Task Load and Fatigue in AnesthesiologyResidents: A Simulation-Based Study.
- McNeer et al 2016
- used 2 validated psychometric survey tools - 1) NASA Task Load Index (NASA-TLX) and 2) Swedish Occupational Fatigue Inventory
- showed that noise during surgery can increase stress
- McNeer et al 2016
Team factors
Team factors describe the group dynamics of the OR team and include teamwork, communication, and leadership. In a recent report of voluntarily reported sentinel event data from 2004-2013, the Joint Commission analyzed 796 major operative and post-operative complications and found communication (53%) and leadership (40%) to be the primary root causes. Other studies have also identified communication and team breakdowns in the OR as a major factor contributing to adverse events. Mazzocco et al observed team behaviors in the OR and found that lack of teamwork during a surgical procedure is correlated to patient complication with an odds ratio of 4.82 (95% confidence level, adjusted for ASA score). In a similar observational study, Lingard et al found that 30% of team exchanges involved a communication failure. One-third of these failures negatively affected patient safety by increasing cognitive load, interrupting routine and increasing tension in the OR. A study involving surgeon-review of malpractice claims has confirmed these findings: 23% of surgical claims involving surgical error or patient injury has also involved a communication breakdown.
Individual factors
Individual factors describe the knowledge, competence, and physical and mental health that pertain to individuals from the operating team. Technical surgical skill is a frequently studied factor in surgical error analysis. Through the analysis of bariatric laparoscopic videos, Birkelmeyer et al found that better technical skill was associated with fewer complications, and reduced risk of re-operation or readmission. Other studies have looked at case volume across centers, and have shown that patient outcomes improve with high-volume surgeons and high-volume centers– suggesting that high-volume surgeons are perhaps more experienced and commit less errors as compared to low-volume surgeons. In fact, Novick et al followed patient outcomes of an academic surgeon over a 10-year period and found that outcome improved in a linear fashion from year 0 to 10 – indicating that experience does influence patient outcome. Another risk factor to patient outcome is sleep deprivation of the healthcare professional. Sleep deprivation can hinder hand–eye coordination, increase error rate and prolong the time taken to complete a surgical task as shown in simulated laparoscopic surgery. Two prospective studies have shown that sleep-deprived medical interns who work extended 24-hour shifts tend to commit 36% more serious medical errors; make 5 times as many diagnostic errors, and have twice as many on-the-job attention failures at night as compared to their counter-parts who are not sleep-deprived.
Development and validation of a surgical workload measure: the surgery task load index (SURG-TLX).
Wilson et al 2011
surgery-specific workload measure SURG-TLX
looked at different stressors - task novelty, physicial fatigue, time pressure, evaluation apprehension, multitasking, distraction
Patient factors
Patient factors refer to the pre-existing pathophysiological factors of the patient. Such factors include obesity, anatomic variation, disease severity and pre-existing morbidities.
Cardiac patients with extreme obesity (BMI 30-50) combined with diabetes mellitus have an increased risk for sternal complications. In spinal surgery, patients who are 75 years and older carry a 4.5 fold increased risk of post-operative mortality when compared to those in the lower age category (45-65 years of age). Current smokers are 2.1 times more likely to have pneumonia after a surgical procedure, 1.87 times more likely to have unplanned intubation, and 1.53 times more likely to have mechanical ventilator than their never-smoker counterparts. These findings indicate that patient factors play a significant role in post-operative outcome, and therefore the use of raw uncorrected patient outcome statistics are misleading in reports. Risk-adjusted scoring systems take into account patient variables in the case mix and provide prediction statistics (observed vs. expected) that can be used as a more accurate measure of surgical performance. For example, Physiological and Operative Severity Score for the enUmeration of Morbidity and Mortality (POSSUM) and its variants (Portsmouth-POSSUM; Colorectal POSSUM) are validated risk-adjusted scoring systems that predict 30-day post-operative mortality and morbidity in surgical patients, taking into account physiological parameters of the patient such as age, cardiac signs, respiratory signs, and systolic blood pressure. Designed for comparative auditing, the Surgical Risk Scale is another scoring system that incorporates the Confidential Enquiry into Perioperative Deaths (CEPOD) grade, the American Society of Anesthesiologists (ASA) grade, and the British United Provident Association (BUPA) grade into a multivariate model to predict morbidity and mortality.