Prolonged ventilation post cardiac surgery - tips and pitfalls of the prediction game

Abstract

BackgroundFew available models aim to identify patients at risk of prolonged ventilation after cardiac surgery. We compared prediction models developed in ICU in two adjacent periods of time, when significant changes were observed both in population characteristics and the perioperative management.MethodsWe performed a retrospective review of two cohorts of patients in our department in two subsequent time periods (July 2007 - December 2008, n = 2165; January 2009 - July 2010, n = 2192). The study was approved by the Institutional Ethics Committee and the individual patient consent was not required. Patients were divided with regard to ventilation time of more or less than 48 hours. Preoperative and procedure-related variables for prolonged ventilation were identified and multivariate logistic regression analysis was performed separately for each cohort.ResultsMost recent patients were older, with more co-morbidities, more frequently undergoing off-pump surgery. At the beginning of 2009 we also changed the technique of postoperative ventilation. Percentage of patients with prolonged ventilation decreased from 5.7% to 2.4% (p < 0.0001).Preoperative and procedure-related variables for prolonged ventilation were identified. Prediction models for prolonged ventilation were different for each cohort. Most recent significant predictors were: aortic aneurysm surgery (OR 12.9), emergency surgery (OR 5.3), combined procedures (OR 5.1), valve procedures (OR 3.2), preoperative renal dysfunction (OR 2.9) and preoperative stroke or TIA (OR 2.8).ConclusionsPrediction models for postoperative ventilation should be regularly updated, particularly when major changes are noted in patients' demographics and surgical or anaesthetic technique.

Prolonged Mechanical Ventilation After CABG: Risk Factor Analysis

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“…74 Strokes directly harm neuronal tissue and can afflict multiple sites, which may affect neuronal transmission of respiratory arousal, thereby causing respiratory muscle weakness that translates to a high incidence of respiratory failure. 75 Hypoglycemia, 76 hypothyroidism, 77 and adrenal insufficiency 78 also affect respiratory arousal and can be considered risk factors for respiratory failure in critically ill patients. Thus, endogenous conditions can impair respiratory arousal and are possible contributors to perioperative muscle dysfunction.…”

Validation of APACHE II, APACHE III and SAPS II scores in short- and long-term mortality prediction in a mixed intensive care unit in Poland: a cohort study

“…On the one hand, this drawback encourages us to extend this prospective analysis to a larger group of patients. On the other hand, it must be remembered that the population of critically ill subjects changes over time and, therefore, diagnostic accuracy parameters can change dynamically (39). Differences in the performance of scores may result from variation in the case mix, standards, the structure and organization of medical care, as well as lifestyles and genetic differences between populations (7).…”