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Haemodynamics

Inhaled iloprost in the management of pulmonary hypertension in infants undergoing congenital heart surgery: 084

Mueller, M.; Neuhaeuser, C.; Noest, R.; Akintuerk, H.; Welters, I.; Hempelmann, G.

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European Journal of Anaesthesiology: June 2004 - Volume 21 - Issue - p 3

Introduction: Impaired endothelium-dependant pulmonary artery relaxation is present in children with high pulmonary flow and pressure which might be exacerbated by cardiopulmonary bypass (CPB) [1]. The use of aerosolized Iloprost has shown to be safe and effective in adults with pulmonary hypertension [2]. However, no data is available about the intra-operative use of inhaled iloprost in infants <1 year with pulmonary hypertension undergoing cardiac surgery.

Method: Eight infants with a median age of 6 months (range 3 days-8 months) undergoing cardiac surgery with CPB for congenital heart disease with increased pulmonary flow and/or increased pulmonary vascular resistance were included in this case-control-study. After weaning off CPB, infants with mean pulmonary artery pressure >15mmHg received inhaled iloprost (2.5 μg kg−1 over 15min) using an ultrasonic nebulizer (Optineb®, Nebu-Tec, Elsenfeld, Germany). Mean pulmonary artery pressure (MPAP) and mean arterial pressure (MAP) were measured and the ratio MPAP/MAP was calculated before and 30min and 60min after starting iloprost inhalation. The need of vasoactive drugs after weaning off CPB was analysed. Repeated measures ANOVA with Tukey test was used to compare MPAP/MAP. P < 0.05 was considered significant.

Results: Mean MPAP/MAP decreased after inhaled iloprost from 0.64 ± 0.1 to 0.5 ± 0.1 at 30min and 0.47 ± 0.1 at 60min, respectively (P < 0.05). To keep MAP >45mmHg a norepinephrine infusion was necessary in one patient. The individual courses of MPAP/MAP are demonstrated in the figure.

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Discussion: A single dose inhaled iloprost decreases MPAP/MAP in infants after weaning off CPB by 21% and 25% after 30min and 60min, respectively. This indicates selective pulmonary vasodilating effects. However, vasopressor support was necessary in one infant. Although inhaled nitric oxide (iNO) is widely used to decrease pulmonary vascular resistance in infants undergoing cardiac surgery, the effects of iNO varies among patients, rebound phenomena have been described, and cumbersome devices are necessary to administer iNO safely. Inhaled iloprost may therefore be an alternative for selective pulmonary vasodilatation in infants undergoing cardiac surgery because it is effective, easy to use and long acting. Furthermore, from the economic point of view, inhaled iloprost may be attractive because iNO became very expensive after FDA approval.

References:

1 Celermajer DS, Culen S, Deanfield JE, et al. Impairment of endothelium-dependent pulmonary artery relaxation in children with congenital heart disease and abnormal pulmonary hemodynamics. Circulation 1993; 87: 440-446.
2 Olschewski H, Simonneau G, Galie N, et al. Inhaled iloprost for severe pulmonary hypertension. N Engl J Med 2002; 347: 322-329.
© 2004 European Society of Anaesthesiology