A Case Control Study On Prediction Modeling Of Dysfunctional Ventilator Weaning Response Among Postoperative Cabg Patients

Background: Although the majority of coronary artery bypass graft (CABG) surgery patients are extubated within 6 to 8 hours following surgery, 20% to 40% of patients remain intubated 12 hours after surgery due to dysfunctional ventilator weaning response (DVWR). DVWR associated with increased morbidity and mortality (30% to 43%) following CABG surgery. There is little known about the prediction of DVWR. Objective: purposes of this research study were to describe the characteristics of Cardio Pulmonary Indicators (CPI) among patients with normal ventilator weaning response (NVWR) and dysfunctional ventilator weaning response (DVWR) after coronary artery bypass graft (CABG) surgery, to find the differences in characteristics of cardiopulmonary indicators between patients with NVWR and DVWR after CABG surgery, and to build a prediction model for DVWR with significant antecedence. Methods: This study utilized a retrospective case control study with time series design. A purposive sampling technique was used to recruit 300 subjects from a retrospective audit of electronic medical records of patients who underwent CABG surgery between May 2003 and February 2006. Among the 300 subjects, 100 subjects constituted the case group and 200 constituted the control group. Data analysis included descriptive and inferential statistics using SAS programs. Results: Findings revealed that several antecedence including COPD (OR 5.46), CHF ( OR3.93), decrease in 10mm/Hg MAP (OR 1.91) , decrease in 5 points of RR (OR 2.97), decrease in 2 points mean of CO ( OR 1.94), increase in 5mm/Hg of PAD ( OR 3.64), and decrease of 10mm/Hg in PASP ( OR3.05) were significantly associated with DVWR. Conclusions: In this study, COPD, CHF, MAP, RR, CO, PAD, and PASP are found as significant predictors for DVWR after CABG surgery. The implication of these findings includes using these predictors in ventilator weaning protocols after CABG surgery may prevent DVWR. Therefore, this study recommends that ventilator weaning criteria be developed considering the significant predictors for postoperative CBAG patients.