Background. The natural history of an uncorrected congenital heart disease especially after two years of age is
the development of pulmonary hypertension. Among left -to-right shunts, when the pre-operative pulmonary artery
pressure rises about two-thirds the systolic blood pressure, the risk for postoperative pulmonary hypertensive crisis
increases and determines the surgical risk, morbidity, and mortality. This study was therefore conceptualized to determine the effect of inhalational or aerosolized prostacyclin analogue (lIoprost) in the prevention of postoperative pulmonary hypertensive crisis when given at least 48 hours in the postoperative period. The specific objectives are: (1) to determine the effect of aerosolized lIoprost on the oxygen saturation, systolic and diastolic BP, tricuspid and pulmonary regurgitations, pulmonary artery pressure, Qp/Qs and pulmonary vascular resistance (RpRs), and (2) to determine the effect on the following clinical parameters: occurrence of pulmonary hypertensive crisis, length of hospital stay, duration of mechanical ventilation, and in-house mortality.
Method. This is a randomized double-blind placebo controlled study. Patients were divided into two groups:
Group I received every 6 hours aerosolized lIoprost for 48 hours, and group 11 was the control group, given nebulized saline solution. Randomization was done by using a table of random samples. Evaluation of parameters was done at O-hour, 24- hour, and 48-hour postoperatively. There were 19 p~\ients_1nrolled in the study: ten in Group I and nine in Group 11. Aerosolized lIoprost was given at a dose of 25 ng. kg min and was given at 6-hour interval for 48 hours.
Results. There was no difference in the tricuspid regurgitation jet in both groups, but a significant dropped in
pulmonary regurgitation jet was noted in the lIoprost group 48 hours post-operatively (p 0.040). Pulmonary artery
pressure analysis showed a more significant drop at the end of 48 hour (p 0.002). Both groups showed a decrease in pulmonary vascular resistance with a higher drop in the placebo group at 24 hours (p 0.028) and a more significant decrease at 48 hours in the lIoprost group (p 0.012). There was a decreasing trend in the Qp/Qs ratio from pre-operallve levels to 48 hours post-operatively but these were not statistically significant. Increasing the sample size is recommended. No mortality in both groups with no side effects noted.
Conclusion. Aerosolized lIoprost given every 6 hours can be an important pharmacologic agent to modify the
pulmonary vascular bed in the immediate postoperative period to prevent pulmonary hypertensive crisis among children with CHD who undergo surgical correction. It is suggested that pre-operative aerosolized lIoprost nebulization as preoperative pulmonary vasodilatation may be started 48 hours preoperatively to significantly drop the PAPand pulmonary vascular resistance in the immediate post-operative period.