Predictors of postoperative pulmonary complications in children undergoing cardiothoracic surgery at the Philippine Heart Center (PREdICt Phase I).

Background. Postoperative pulmonary complication (PPCs) increases the morbidity of post cardiothoracic surgery patients especially of the lower age group. This study was done to determine the risk factors associated with postoperative pulmonary complications following cardiothoracic surgery in children 6 years old and below who underwent cardiothoracic surgery from November 1, 2010 - October 31, 2011 at the Philippine Heart Center.

Methods. This is a prospective cohort study done in a total of 120 patients, 52 of whom performed tidal breathing analysis. Upon admission, data collection sheet was filled up with the demographic and clinical characteristics of patients included, the preoperative risk factors identified, the American Society of Anesthesiologists (ASA) physical status score, and the Risk Adjustment in Congenital Heart Surgery-I (RACHS-1) classification. Perioperatively, the surgical procedures done, cardiopulmonary bypass time and aortic cross clamp time were noted. Postoperatively, the total duration of postoperative mechanical ventilation, recovery room stay, intensive care unit stay, length of postoperative hospital stay and the condition on discharge were also noted. Patients were then evaluated for postoperative pulmonary complications. Primary outcome was development of PPCs. Secondary outcomes included the duration of postoperative mechanical ventilation, recovery room (RR) stay, pediatric intensive care unit (PICU) stay, overall length of postoperative hospital stay and mortality. For qualitative data, proportions/percentages were computed. For quantitative data, means and standard deviation were used. Comparisons of categories between with and without postoperative complications were done using Chi-square and independent T-test for all continuous variables at a = 0.05 (5%). All variables that presented a p-value of :5 0.050 were considered independent predictors of postoperative pulmonary complications.

Results. The rate of PPCs in this study was 73% with atelectasis, pneumonia and air leaks as the top1hree most common PPCs. Patients with PPCs had a longer duration of postoperative mechanical ventilation, lonqer RR and PICU stay and a longer overall length of hospital stay. There were 14 (12%) who died in the study, all with PPCs. There is the tendency that as the number of postoperative pulmonary complication increases, the rate of mortality also increases. Risk factors associated with PPCs were history of respiratory tract infection (RTI), preoperative mechanical ventilation, high pulmonary artery pressure (PAP), hypercarbia, hemoconcentration, lymphocytopenia, prolonged protime, hypoalbuminemia, complexity of cardiac surgery using the RACHS -1 scoring system and high ASA score. Logistic regression analysis however, only showed history of RTI and preoperative mechanical ventilation as independent risk factors for the development of PPCs.

Conclusions. Incidence of PPCs in children 6 years old and below undergoing cardiothoracic surgery is high and is associated with need for prolonged mechanical ventilation and longer RR, PICU and hospital stay postoperatively. Therefore, identifying the risk factors to prevent its occurrence is of paramount importance.