Phenylephrine increases pulmonary blood flow in children with tetralogy of Fallot.
OBJECTIVE
Although it has been reported that the increase in blood pressure improves arterial oxygen saturation (SaO(2)) in children with tetralogy of Fallot, no prospective study has demonstrated that an increase in blood pressure induces an increase in pulmonary blood flow in these patients. The purpose of this study was to see whether a phenylephrine-induced increase in systemic blood pressure increased pulmonary blood flow, resulting in improved arterial oxygenation in tetralogy of Fallot.


METHODS
In 14 consecutive children with tetralogy of Fallot (2-32 months old), transesophageal pulsed Doppler signals of left upper pulmonary venous flow (PVF) velocity were recorded before and four minutes after 10 micro g x kg(-1) of phenylephrine i.v. Simultaneously, arterial blood gas analysis and hemodynamic measurements were performed. The minute distance (MD) was calculated as the product of the heart rate and the sum of time-velocity integrals of PVF.


RESULTS
Phenylephrine iv increased mean arterial blood pressure from 54 +/- 8 mmHg to 73 +/- 10 mmHg. This phenylephrine-induced hypertension significantly increased SaO(2) and MD (92.0 +/- 7.5 vs 95.0 +/- 5.0% and 1318 +/- 344 vs 1533 +/- 425 cm x min(-1), respectively). There was a significant correlation (r = 0.72) between the change in MD and the change in SaO(2).


CONCLUSIONS
Our results suggest that the phenylephrine-induced increase in systemic blood pressure produces an increase in pulmonary blood flow in tetralogy of Fallot. Our results further suggest that this increase in pulmonary blood flow is involved in the mechanism of phenylephrine-induced improvement of arterial oxygenation in tetralogy of Fallot.
Tanaka
Katsuya
K
Department of Anaesthesiology, Tokushima University School of Medicine, Tokushima, Japan. ktanaka@mcw.edu
Kitahata
Hiroshi
H
Kawahito
Shinji
S
Nozaki
Junpei
J
Tomiyama
Yoshinobu
Y
Oshita
Shuzo
S
D001783:Blood Flow Velocity; D001784:Blood Gas Analysis; D002648:Child; D002675:Child, Preschool; D018619:Echocardiography, Doppler, Pulsed; D017548:Echocardiography, Transesophageal; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000139:chemically induced; D007223:Infant; D008297:Male; D010100:Oxygen / Q000097:blood; D010656:Phenylephrine / Q000494:pharmacology*; D011652:Pulmonary Circulation / Q000187:drug effects*; D011667:Pulmonary Veins / Q000000981:diagnostic imaging; D013771:Tetralogy of Fallot / Q000000981:diagnostic imaging / Q000188:drug therapy*; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
D014662:Vasoconstrictor Agents; D010656:Phenylephrine; D010100:Oxygen