A. Haraldsson et al., Inhaled prostacyclin and platelet function after cardiac surgery and cardiopulmonary bypass, INTEN CAR M, 26(2), 2000, pp. 188-194
Objective. To study the effects of 6 h inhalation of aerosolized prostacycl
in (PGI(2)) on platelet function.
Design: In a prospective, double-blind, randomized study, 28 patients sched
uled for elective cardiac surgery requiring cardiopulmonary bypass (CPB), r
eceived either 0.9% sodium chloride (n = 8), PGI(2) 5 mu g x ml(-1) (n = 10
) or PGI(2) 10 mu g, ml(-1) (n = 10) as an aerosol for 6 h postoperatively.
Setting: Cardiothoracic intensive care unit at a university hospital. Inter
ventions: All patients were studied immediately after surgery during mechan
ical ventilation and sedation. The PGI(2) solutions or saline were administ
ered with a jet nebulizer.
Measurements and results: Bleeding time and chest tube drainage were measur
ed. Blood samples for platelet aggregation, thrombelastography (TEG) and an
alysis of coagulation parameters and the stable prostacy clin metabolite 6-
keto-PGF(1)alpha were obtained immediately before inhalation and after 2, 4
and 6 h of inhalation. After 6 h of PGI(2) inhalation, regardless of admin
istered dose, there was a lower rate of platelet aggregation and a lower ma
ximal increase in light transmission in response to adenosine diphosphate (
ADP) than in the control group. The TEG variable reaction rime (R) was prol
onged after 4 and 6 h of inhalation in the PGI(2) group receiving 10 mu g x
ml(-1). There were no differences between groups with respect to bleeding
time and chest tube drainage or any of the other variables examined.
Conclusion: Inhalation of PGI(2) for 5 h in patients after cardiac surgery
is associated with impaired platelet aggregation detected by in vitro techn
iques, with no in vivo signs of platelet, dysfunction.