Evaluating the reliability and reproducibility of the Ottawa Thoracic Morbidity and Mortality classification system.

BACKGROUND: Minimizing adverse events after surgery is widely recognized as an important indicator of quality; yet no consensus has been reached on how to standardize the reporting of adverse events after surgical procedures. Our objectives were to develop a standardized classification system to monitor both the presence and severity of thoracic morbidity and mortality, and to evaluate its reliability and reproducibility among a national cohort of thoracic surgeons. METHODS: To assess the Thoracic Morbidity and Mortality classification system (based on the Clavien-Dindo classification of adverse events), a 31-item questionnaire was sent to all members of the Canadian Association of Thoracic Surgeons in August 2009, consisting of a general description of the Thoracic Morbidity and Mortality severity grades, 20 case-based questions of postoperative adverse events to be classified, and questions regarding personal judgments. We derived descriptive and quantitative information using weighted Kappa statistics. RESULTS: Fifty-two (54.7%) thoracic surgeons completed the questionnaire; 41 (78.8%) of the respondents were affiliated with an academic teaching hospital. A total of 1,326 individual weighted Kappa statistics were calculated for all distinct pairs of raters, of which 1,152 (87%) were greater than 0.81, a range that is interpreted as "almost perfect agreement." A further 174 (13%) were in the range between 0.61 and 0.8, interpreted as "substantial agreement." All results were statistically significant (p < 0.0001). The classification system was regarded as straightforward (98% of the respondents), reproducible (94%), logical (92%), and useful (98%). CONCLUSIONS: The modified classification system appears to offer objective, reliable, and reproducible reporting of thoracic morbidity and mortality, and thus may assist continuous quality improvement in thoracic surgery.

Systematic classification of morbidity and mortality after thoracic surgery.

BACKGROUND: Objective reporting of postoperative complications is the foundation of surgical quality assurance. We developed a system to identify both presence and severity of thoracic morbidity and mortality, and evaluated its feasibility and utility over the first two years of its implementation. METHODS: The system was based on the Clavien-Dindo classification, in which the severity of a complication is proportional to the effort to treat it. Definitions were developed by peer review and questionnaire. All patients undergoing thoracic surgery (January 2008 to December 2009) were prospectively evaluated. RESULTS: A total of 953 patients (mean age 61 years; range, 14 to 95) underwent thoracic surgery (total # cases 1260), of which 369 patients had at least one complication (29.3% procedures). Grades I and II include minor complications requiring no therapy or pharmacologic intervention only. Grades III and IV are major complications that require surgical intervention or life support. Grade V complications result in patient death. Grades I, II, III, and IV complications comprised 4.9%, 63.9%, 21.1%, and 7.8% of all complications; overall mortality rate (grade V) was 2.2%. The most common complications were prolonged air leak (18.8%) and atrial fibrillation (18.2%) after pulmonary resection, and atrial fibrillation (11.5%) after esophagectomy-gastrectomy. Prolonged air leak led to a major complication (13%), readmission (17%), or prolonged hospital stay (29%) to a greater extent than atrial fibrillation (3%, 2%, and 7%, respectively). CONCLUSIONS: This standardized classification system for identifying presence and severity of thoracic surgical complications is feasible, facilitates objective comparison, identifies burden of illness of individual complications, and provides an effective method for continuous surgical quality assessment.