Before the initiation of the study, we revised our previously published surgical complication grading system to include all potential postoperative surgical complications. Combining the Common Terminology Criteria for Adverse Events system with systematic review of surgical complications reported in our institution over a period of 5 y, we generated a table including all potential surgical complications grouped by physiology–anatomy systems, coded, and each complication was divided into a five-tiered scale severity grading (Appendix A
). The table was printed as a pocket book, laminated, and distributed to all of the department's surgical staff during a study initiation meeting with detailed explanations on its proper use. The study protocol was reviewed and approved by the Hadassah Medical Center Institutional Review Board (Helsinki Committee), protocol No. HMO_0646-08 (NCT01168193).
2.1 Procedures and patients
All surgical procedures performed at the Department of Surgery, Hadassah-Hebrew University Medical Center, Mount Scopus between January 1st and December 31st, 2009 were prospectively recorded and classified according to the International Classification of Diseases 9 codes. Data were verified by the study coordinator with the International Classification of Diseases 9 reported by the operating room personnel for billing purposes. Operative details included type of surgery, surgical approach (laparoscopy versus open), emergency versus elective procedure, and presence of oncological indication. Patients' demographics, American Society of Anesthesiology (ASA) score, current medications, and comorbid conditions were also recorded.
2.2 Complication recording
Complications were defined as secondary events (or unintended consequences) deviating from the ideal course of convalescence that occurred after the operation, resulting in changes in management (diagnostic or therapeutic intervention) and delay in complete recovery and or planned subsequent therapy, or chronic disability. This broad definition also includes asymptomatic documented complications. Complications that occurred during admission were recorded by the department staff on a daily basis. Inpatients were evaluated daily by the surgical staff and any complication encountered was classified and graded according to the table. On discharge, each patient was given a spreadsheet to be filled by a surgeon or a nurse at the follow-up clinic recording the presence of a complication or several complications, its code according to the table, and its severity. All complications were recorded in a computerized database designed for the study.
Data were collected for 30 postoperative days and analyzed by the patients' characteristics, procedure performed, complication code and grade, and hospital LOS.
To include all surgical complications, a study coordinator retrospectively reviewed all procedures performed and all patients not reported to have a complication were contacted by the medical staff and either interviewed or examined at the follow-up clinic. The study coordinator had access to the complications previously reported by the surgeons and documented complications that were not captured by the staff.
Preexisting medical conditions that did not change over the hospital course were not considered as adverse events. All complications were classified, coded, and graded by severity according to the “Surgical Complications Severity Scoring System.”
Grade 1 included minor, asymptomatic complications that did not require medical therapy or radiological nor surgical intervention (e.g., bedside wound care).
Grade 2 complications were defined as complications requiring pharmacologic therapy or any minor interventions (e.g., intravenous therapy, transfusions, or total parenteral nutrition [TPN]).
Grade 3 complications were defined as complications treated by invasive procedures other than surgery including interventional radiology or endoscopy (e.g., operative drainage of an abscess).
Grade 4 included complications that required surgical intervention and complications resulting in permanent loss of function of an organ (e.g., reduction in performance status after postoperative respiratory failure).
Grade 5 included complications resulting in death.
Any death occurring within 30-days of operation or during the same hospitalization was considered perioperative mortality. Hospital and intensive care unit length of stay as well as disposition at discharge (discharge home, to assisted living or to rehabilitation facility and death) were recorded, and calculated from the time of first operation to discharge or death.