Abstract
Background and objectives: Inhaled nitric oxide (iNO) is increasingly replacing the use of hyperventilation induced alkalosis and non-selective vasodilators to treat pulmonary hypertension in the early postoperative course after congenital heart surgery. Because weaning from iNO is often difficult, complicated by a rebound phenomenon, we investigated if the presence of this phenomenon may prolong the duration of ventilatory support and the length of stay in the intensive care unit (ICU) compared to earlier treatment. Design: Retrospective chart review. Setting: An eight bed medical-surgical paediatric intensive care unit in a university taking care of around 150 postoperative cardiac children a year. Patients: Comparison of two groups of children matched for age at operation, preoperative pulmonary to systemic resistance ratio, and postoperative pulmonary to systemic pressure ratio among 155 children operated on for a ventricular septum defect (VSD) associated with pulmonary hypertension (PHT) between February 1986 and January 1996, one group treated with iNO, the other without. Measurements and results: Early postoperative morbidity was assessed using the duration of ventilatory support and length of stay in the ICU. Among 155 operated children, six patients treated with iNO and ten control patients, treated conventionally, met our matching criteria. The median length of ventilatory support for the iNO group was 6.5 (range 2-16) days and 2 (range 1-8) for the control group (p < 0.05). The length of stay in the ICU was 9 (range 5-23) days for the iNO group versus 4.5 (range 3-10) days for the control group (p < 0.05). Conclusion: Treatment of postoperative PHT, after ventricular septal closure, with iNO is associated with a significant increase in ventilator days and length of stay in the ICU compared to earlier treatment without iNO. These findings may reflect the difficulties often encountered when weaning patients from iNO.