title: Phenylephrine increases pulmonary blood flow in children with tetralogy of Fallot.
abstract: 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.
authors: Department of Anaesthesiology, Tokushima University School of Medicine, Tokushima, Japan. ktanaka@mcw.edu
authors: Katsuya
authors: K
authors: Tanaka
authors: Hiroshi
authors: H
authors: Kitahata
authors: Shinji
authors: S
authors: Kawahito
authors: Junpei
authors: J
authors: Nozaki
authors: Yoshinobu
authors: Y
authors: Tomiyama
authors: Shuzo
authors: S
authors: Oshita
mesh_terms: 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*
chemical_list: D014662:Vasoconstrictor Agents; D010656:Phenylephrine; D010100:Oxygen