# Multicenter observational study of patients who underwent cardiac surgery and were hospitalized in an intensive care unit (BraSIS 2): study protocol and statistical analysis plan

## TL;DR

This study aims to understand the risk factors and complications following cardiac surgery by observing patients in Brazilian intensive care units.

## Contribution

The study introduces a multicenter observational protocol to assess postoperative complications and mortality in cardiac surgery patients in Brazil.

## Key findings

- The study will identify risk factors for mortality and severe postoperative complications within the first 3 postoperative days.
- It will evaluate the incidence of various severe complications like acute myocardial infarction and septic shock.
- The research will describe patient demographics and surgical procedures across multiple Brazilian intensive care units.

## Abstract

The perioperative management of patients undergoing cardiac surgery is highly complex and involves numerous factors. There is a strong association between cardiac surgery and perioperative complications. The Brazilian Surgical Identification Study (BraSIS 2) aims to assess the incidence of death and early postoperative complications, identify potential risk factors, and examine both the demographic characteristics of patients and the epidemiology of cardiovascular procedures.

BraSIS 2 is a multicenter observational study of patients who undergo cardiac surgery and who are admitted to the intensive care unit. The primary objective is to describe the risk factors and incidence of mortality or severe postoperative complications occurring within the first 3 postoperative days of cardiac surgery or until intensive care unit discharge (whichever event occurs first). Severe postoperative complications include acute myocardial infarction, acute respiratory distress syndrome, cardiorespiratory arrest with return of spontaneous circulation, Kidney Disease Improving Global Outcomes stage ≥ 2, a new surgical approach being conducted in an unscheduled event of urgency or emergency, renal replacement therapy, septic shock, severe bleeding, severe hemodynamic instability, stroke, unplanned reintubation, and unplanned use of a circulatory assistance device. The secondary outcomes include the evaluation of patient characteristics and descriptions of the performed surgeries and administered anesthesia. This study will also assess intraoperative and postoperative complications, as well as risk factors associated with postoperative complications and mortality. We expect to recruit 500 patients from at least 10 Brazilian intensive care units. Trial registration: NCT06154473; partial results.