The preoperative and intraoperative risk factors for early postoperative mechanical ventilation after scoliosis surgery: A retrospective study

Background: Patients undergoing corrective surgery for scoliosis of spine are commonly ventilated in our institute after the operation. Postoperative mechanical ventilation (PMV) and subsequent prolongation of intensive care unit stay are associated with increase in medical expenditure and complications such as ventilator-associated pneumonia. Identification of factors which may contribute to PMV and their modification may help in allocation of resources effectively. The present study was performed to identify preoperative and intraoperative factors associated with early PMV after scoliosis surgery. Methods: One hundred and two consecutive patients who underwent operation for scoliosis correction between January 2006 to July 2011 were reviewed retrospectively. Patients requiring PMV included patients who were not extubated in the operating room and were continued on mechanical ventilation. Preoperative and intraoperative factors which were analysed included age, gender, weight, cardiorespiratory function, presence of kyphosis, number and level of vertebrae involved, surgical approach, whether thoracoplasty was done, duration of surgery, blood loss, fluids and blood transfused, hypothermia and use of antifibrinolytics. Results: The average age of the patients was 14.31 +/- 3.78 years with female preponderance (57.8%). Univariate analysis found that longer fusions of vertebrae (more than 8), blood loss, amount of crystalloids infused, blood transfused and hypothermia were significantly associated with PMV (P<0.05). Independent risk factors for PMV were longer fusion (Odds Ratio (OR), 1.290; 95% confidence interval (CI), 1.038-1.604) and hypothermia (OR, 0.096; 95% CI, 0.036- 0.254; P<0.05). Conclusion: The authors identified that longer fusions and hypothermia were independent risk factors for early PMV. Implementation of measures to prevent hypothermia may result in decrease in PMV.