Definition and classification of postoperative complications after cardiac surgery: a pilot Delphi study

Background: Postoperative complications following cardiac surgery are common and represent a serious burden to health services and society. However, there is a lack of consensus among experts on what events should be considered as a ‘complication’ and how to assess their 'severity'.

Objective: This study aimed to consult domain experts to pilot a development of a definition and classification system for complications following cardiac surgery with the goal to allow the progression of standardized clinical processes and systems in cardiac surgery.

Methods: We conducted a Delphi study, which is a well-established method to reach expert consensus on complex topics. Two rounds of surveys were sent out to domain experts, including cardiac surgeons and anesthetists, to define and classify postoperative complications following cardiac surgery. The responses to open-ended questions were analyzed using a thematic analysis framework.
Results: In total, N=71 and N=37 experts’ opinion were included in the analysis in Round 1 and Round 2 of the study, respectively. Cardiac anesthetists and cardiac critical care specialists took part of the study. Cardiac surgeons did not participate. Experts agreed that a classification of postoperative complications for cardiac surgery is useful, and a consensus was reached for the generic definition of a postoperative complication in cardiac surgery. Consensus was also reached on classification of complications according to the following 4 levels: “Mild”, “Moderate”, “Severe” and “Death”, and consensus was also reached on a definition of “Mild” and “Severe” categories of complications.

Conclusions: Domain experts agreed on the definition and classification of complications in cardiac surgery for "Mild" and "Severe" complications. The standardization of complication identification, recording and reporting in cardiac surgery should help the development of quality benchmarks, clinical audit, care quality assessment, resources planning, risk management, communication, and research.