Objective

Evaluation of the role of inhaled Nitric Oxide (iNO) in critical peri-operative pulmonary hypertension (PAH).

Methods

This was an observational study of 41 consecutive patients (age 15 days - 28 years, median-4 months) who required iNO for management of critical peri-operative PAH from January 2001 to August 2008.

Results

The diagnostic categories and outcome are shown in table 1. iNO (10 to 80 ppm, mean duration 79.6 hours) was added to a regimen of Adrenaline/Dopamine/Milrinone for systemic/suprasystemic pulmonary pressures causing inability to come off bypass (n33, 80%), inability to be weaned off ventilator (n6, 15%) or persistent hypoxemia (n2, 5 %). Outcome measures were successful management of the crisis, decrease in PA pressure and discharge from hospital. Mean PA pressure of the group decreased by 10.5 mm of Hg (p<0.05), post iNO (Figure 1). All the patients who were started on iNO were weaned-off bypass successfully. Ten (24.4%) patients (age 1 month – 28 years, median 4 months) showed no response to iNO and died in the ICU (TGA/VSD 4, TAPVC 4). 2 responders died later from septicemia. All others were extubated and discharged. The survivors had significantly lower mean PA pressures compared to those who died (p<0.05). Serum methemoglobin levels were > 1.5% in 11(27 %) patients.

Conclusion

Addition of iNO to a conventional drug regimen is a useful strategy for salvaging critically ill patients with peri-operative PAH especially when there is difficulty to come off bypass or ventilator.