Inhaled nitric oxide in infants and children after open heart surgery.

Objective: To assess the effects of inhaled nitric oxide (NO) on oxygenation and pulmonary circulation in infants and children with critical pulmonary perfusion and/or hypoxemia after open heart surgery.

Study: A prospective case series report.

Setting: A multidisciplinary pediatric intensive care unit in a University hospital

Patients: From June 1993 to March 1996 37 pediatric patients after open heart surgery were treated with inhaled NO. Their mean age was 2.9+/-0.6 years, their mean body weight 12.6+/-1.8 kg.

Methods: Inhaled NO was applied using a microprocessor controlled delivery system which continuously measured NO and NO2 by the chemilumniscence method. Monitoring included ECG, continuous pulse oximetry (SaO2), arterial (AP), central venous (CVP) and left atrial (LAP) pressures and in 8 patients a pulmonary artery (PAP) pressure. Inhaled NO was started at an SaO2 <90% with a fraction of inspired oxygen concentration (FiO2) >0.7, at a mean pulmonary artery pressure (MPAP) >50% of the mean arterial pressure (MAP), and in patients after Fontan-procedure at a CVP-LAP pressure gradient >10 mmHg.

Results: The mean dose of inhaled NO was 3.7+/-0.3 ppm and the mean duration was 112+/-14.7 hours. For the whole group SaO2 increased from 79.6+/-2.3 to 90.1+/-1.5% (p<0.01) within 20 minutes of NO-inhalation. Inhaled NO significantly decreased the MPAP from 47.8+/-4 to 27.5+/-2.3 mmHg (p<0.01) in 8 patients with postoperative pulmonary hypertension and significantly decreased the transpulmonary pressure (CVP-LAP) from 14.3+/-0.8 to 7.3+/-0.9 mmHg (p<0.01) in 16 patients after Glenn- or Fontan-procedure.

Conclusions: Inhaled NO is very effective to decrease pulmonary artery pressure, to improve oxygenation, and to improve Fontan-circulation in infants and children after open heart surgery.