Cardiac Intensive Care Risk factors prolonging ventilation in young children after cardiac surgery: Impact of noninfectious pulmonary complications Patrick Ip, MBBS; Clement S. W. Chiu, MBBS; Y. F. Cheung, MBBS E arly diagnosis of congenital heart disease by fetal echocar- diography, improved perinatal care, innovations in surgical technique and myocardial protection, and better perioperative care have led to more young children surviving cardiac surgery for their underlying congenital heart disease (1, 2). The demand on re- sources for postoperative cardiac care is expected to increase with the increasing complexity of surgery performed at an earlier age. Among other risk factors, duration of mechanical ventilation is an important factor that determines post- operative recovery and outcome (3). Prolonged ventilation is well docu- mented to be associated with major complications and mortality, hence early extubation after cardiac opera- tions in neonates and children is highly desirable (4 – 6). Risk factors associated with prolonged mechanical ventilation after cardiac sur- gery in young children included a high preoperative pulmonary vascular resis- tance, the need for preoperative ventila- tion, longer cardiopulmonary bypass and aortic cross-clamp durations, and need for additional surgical interventions (6, 7). Furthermore, ventilator-associated pneumonia had also been shown recently to account for a major delay in extubation after pediatric cardiac surgery (8, 9). Al- though noninfectious pulmonary compli- cations are also a common occurrence in young children after cardiac surgery and are associated with prolonged stay in the intensive care unit (10), there is a paucity From the Division of Paediatric Cardiology (PI, YFC), Department of Paediatrics and Division of Car- diothoracic Surgery (CSWC), Department of Surgery, Grantham Hospital, The University of Hong Kong, Hong Kong, People’s Republic of China. Funded, in part, by a CRCG research grant, The University of Hong Kong. Address requests for reprints to: Y. F. Cheung, MBBS, Division of Paediatric Cardiology, Department of Paediatrics, Grantham Hospital, 125 Wong Chuk Hang Road, Aberdeen, Hong Kong, People’s Republic of China. E-mail: xfcheung@hkucc.hku.hk Copyright © 2002 by the Society of Critical Care Medicine and the World Federation of Pediatric Inten- sive and Critical Care Societies Objective: To determine risk factors for prolonged ventilation after cardiac surgery in young children and assess the impact of noninfectious pulmonary complications on ventilatory duration. Design: Retrospective case series analysis. Setting: A tertiary pediatric cardiac center. Patients: Clinical records of 222 consecutive children aged <3 yrs undergoing cardiac surgery for congenital heart disease were reviewed. Fifteen patients, consisting of six premature babies and nine who died within 72 hrs of surgery, were excluded. Measurements and Main Results: The demographic data, pre- operative risk factors, surgical procedures performed, intraoper- ative variables, and postoperative complications of the remaining 207 children were reviewed. Univariate analysis was performed to compare patients who required prolonged ventilation (>72 hrs) to those who could be extubated at <72 hrs, and multivariate analyses were performed to identify significant determinants on ventilatory duration and impact of noninfectious complications. Of the 182 patients undergoing open heart surgery, 45 (25%) re- quired prolonged ventilation for a median of 8 days. The latter were significantly younger in age and lighter in weight and were more likely to have Down syndrome, preoperative pulmonary hypertension and ventilatory support, undergone more complex surgery requiring longer bypass and circulatory arrest time, post- operative cardiovascular and pulmonary complications, and ex- tubation failure (all p values <.01). Of the 25 patients who had closed heart surgery, five (20%) required prolonged ventilation for a median of 14 days. The latter were more likely to require preoperative ventilation, have undergone more complex surgery, had postoperative cardiovascular and pulmonary complications, and had extubation failure (all p values <.05). Cox proportional hazard regression identified body weight (p < .001), Down syn- drome (p  .02), need for preoperative ventilation (p < .001), complexity of surgery (p < .001), cardiovascular complications (p < .001), and infective (p < .001) and noninfective (p < .001) pulmonary complications to be significant factors that deter- mined the ventilatory duration. Noninfectious pulmonary com- plications occurred in 31.9% (58/182) and 20% (5/25) of patients after open and closed heart surgery, respectively. In the absence of other risk factors, the median time to extubation was similar between patients with and without noninfectious complica- tions (1 vs. 0.8 day). However, in the presence of other risk factors, noninfectious pulmonary complications prolonged the median time to extubation from 8 to 18 days. Logistic regres- sion identified Down syndrome (p  .005), preoperative ven- tilation (p  .001), complexity of surgery (p  .006), and bypass time (p  .005) as risk factors for development of noninfectious pulmonary complications. Conclusions: Noninfectious pulmonary complications that oc- curred commonly after cardiac surgery in young children prolong ventilatory duration only in the presence of other risk factors, with which it acts in a synergistic fashion. (Pediatr Crit Care Med 2002; 3:269 –274) KEY WORDS: mechanical ventilation; pediatric cardiac surgery; risk factors; noninfectious pulmonary complications 269 Pediatr Crit Care Med 2002 Vol. 3, No. 3