Introduction: While most patients have a rapid postoperative recovery after cardiac surgery, some require extended postoperative treatment in the ICU. The burden on hospital resources is enormous for this category of patients. The aim of this study was to evaluate the hospital course of patients who required prolonged postoperative mechanical ventilation and to identify the perioperative factors associated to hospital mortality.
Method: Data of 6404 consecutive adult cardiac surgical cases performed over a 5-yr period at Vita-Salute University, IRCCS San Raffaele Hospital, have been prospectively collected after Ethical Committee approval and individual informed consent. Standard anaesthesia with propofol and medium dose opiates was used in all patients. Patients were weaned from the ventilator as they met the following criteria: haemodynamic stability, no major bleeding, normothermia, and consciousness with adequate pain control. Patients who required prolonged mechanical ventilation (>7 days) were identified. Data were stored electronically and analysed by use of SAS 1999 programme by univariate and multivariate analysis.
Results: Of the 6404 patients who underwent cardiac surgery at our hospital from January 1998 to July 2002, only 179 (2.8%) required prolonged (>7 days) postoperative mechanical ventilation, overall Hospital mortality was 2.9% (183 patients), with significant difference (p < 0.001) between the study group (45.3%) and the control population (2%). Within the study group a stepwise logistic regression analysis identified renal failure (OR 8.1, 95% CI 4.0-16.4), diabetes (OR 3.0, 95% 1.1-8.4), age (OR 1.05, 95% CI 1.01-1.08 per year).
The strain these patients place on personal, system, and financial resources is extreme with disproportionate consumption of ICU resources (54% of ICU ventilators occupied by 3% of the population and 31% bed occupation of the cardio thoracic ICU in the period studied).
Discussion: The main result of this study is that patients with a complicated postoperative course after cardiac surgery, requiring prolonged MV, have a dismal prognosis (45.3% hospital mortality). Preoperative predictors of hospital death among this high risk population are represented by diabetes, older age and acute renal failure that can be either an indicator or a pre-existent factor of MOF
The knowledge of long-term outcome in patients who have sustained major complications after cardiac surgery could help physicians to treat patients and permit more realistic counselling of relatives to better allocate resources toward those with the best chances for acceptable recovery. This could result in more appropriate and enthusiastic use of resources in those likely to recover.
1 Engoren M, Buderer NF, Zacharias A. Long-term survival and health status after prolonged mechanical ventilation after cardiac surgery. Crit Care Med