INHALED VASODILATORS IN
PULMONARY HYPERTENSION
Frostell C
Dept of Anaesthesia and Intensive Care, Danderyd Hospital,
Stockholm, Sweden
Background: Various forms of
lung disease may be complicated by pulmonary hypertension with or without
hypoxaemia. Interest in the use of inhaled vasodilators has increased in
the last few years, after selectivity for the lung vascular bed could be
demonstrated for some compounds. Oxygen, nitric oxide (NO) and
prostaglandins may all cause selective pulmonary vasodilation when inhaled;
and have all been used clinically. Recently, a second North American
placebo-controlled multicenter study conclusively showed that inhaled NO
improved oxygenation and reduced the need for extra-corporeal membrane
oxygenation (ECMO) in near-term and term neonates with hypoxic respiratory
failure (1). These benefits coupled with only moderate side effects have
resulted in the acceptance of inhaled NO as a drug in the U.S.A. 1999, for
term neonates. Other studies have showed promising results with inhaled NO,
when treating infants at risk for postoperative pulmonary hypertension
after congenital heart surgery. Research indicates that the stable
prostacyclin analogue iloprost can be used clinically to reduce pulmonary
artery pressure and improve oxygenation in primary pulmonary hypertension
(2). Both inhaled NO and prostaglandins have been used clinically in the
treatment of acute respiratory distress syndrome, however no randomised
placebo-controlled study has yet been able to prove benefit from such a
strategy.
Conclusion: Inhaled vasodilators are moving from research to clinical use,
and need further study to explore potential benefits and risks.
1. Clark et al, N Engl J Med 2000;
342; 469-474.
2. Hoeper et al, J Am Coll Cardiol 2000; 35;
176-182.
The author declares conflict of interest on the subject of
inhaled NO.