Preoperative C-reactive protein - Albumin ratio as a predictor of requirement for postoperative mechanical ventilation after non-cardiac surgery under general anaesthesia: A prospective observational study (HICARV)

Background and Aims: Mechanical ventilation is an essential but limited resource worldwide. Appropriate perioperative utilisation of such useful resource demands in time prediction where literature does not have enough data. High C-reactive protein (CRP) and low albumin both represent a state of exaggerated inflammation and poor nutrition, the combination of which might represent the sick surgical patients. Therefore, we tried to evaluate the performance of ratio between preoperative CRP and albumin (CAR) for the prediction of postoperative mechanical ventilation. Methods: After approval from the ethics committee and trial registration, the study was carried out over 2 years. It included 580 adults undergoing non-cardiac surgeries under general anaesthesia. Blood samples were collected for estimation of CRP and albumin, and all were followed up for the need of mechanical ventilation in the postoperative period till hospital discharge. Results: Sixty-six of the analysed 569 patients (11.6%) required postoperative mechanical ventilation in whom the median CAR was higher {0.38 (0.10, 1.45)} than those who did not require the same {0.20 (0.07, 0.65)}, although not statistically significant. A ROC curve analysis found that there is a 58% chance that a CAR will distinguish between the patients requiring postoperative mechanical ventilation from those who do not (AUC = 0.58), which is statistically significant (P value = 0.024). Logistic regression did not result in a significant odds of mechanical ventilation with higher ratio {Odds ratio = 1.06 (0.98, 1.16)}. Conclusions: High CRP-albumin ratio was found to be associated with higher need for mechanical ventilation in patients undergoing surgery under general anaesthesia, but failed to predict the need for mechanical ventilation.