Effect of phenylephrine bolus administration on left ventricular function during postural hypotension in anesthetized patients.
OBJECTIVE
To investigate the effect of intravenous (IV) phenylephrine (PHE) bolus administration on left ventricular function in patients who developed postural hypotension during isoflurane anesthesia in the head-up tilt (reverse Trendelenburg) position.


METHODS
Prospective "before-after" trial.


METHODS
Operation theater of a university medical center.


METHODS
15 ASA physical status I and II patients without cardiovascular disorders.


METHODS
The anesthetized patients were tilted from a supine horizontal to a 30-degree reverse-Trendelenburg position. Once a steady state was achieved, PHE 3 micrograms/kg was administered as an IV bolus dose.


RESULTS
Transesophageal echocardiography was used to assess left ventricular function. We measured blood pressure (BP); heart rate; left ventricular end-systolic and end-diastolic area, diameter, and wall thickness; and ejection time at baseline and after tilt, immediately before and for a period of 3 minutes after PHE injection. We calculated fractional area change (FAC), mean velocity of circumferential fiber shortening (mVcf), and end-systolic wall stress. Head-up tilt caused a reduction of mean arterial pressure [from 68 to 54 mmHg (mean)], end-systolic and end-diastolic left ventricular area (from 9.7 to 6.5 cm2 and from 19.2 to 13.1 cm2, respectively) and end-systolic wall stress (from 56 to 33 10(3).dyne/cm2). FAC and mVcf remained unaltered. PHE administration restored baseline values or overcompensated the changes caused by tilt. FAC slightly decreased in response to PHE (from 0.51 to 0.43), end-systolic wall stress increased to 83 10(3).dyne/cm2, and mVcf remained unchanged.


CONCLUSIONS
PHE bolus administration effectively restored BP and cardiac filling, which were reduced after head-up tilt, without causing a relevant impairment of left ventricular function or an increase in end-systolic wall stress above the upper normal limit.
Goertz
A W
AW
Department of Anesthesiology, University of Ulm Medical Center, Germany.
Schmidt
M
M
Lindner
K H
KH
Seefelder
C
C
Georgieff
M
M
D000328:Adult; D000769:Anesthesia, Inhalation; D017558:Elective Surgical Procedures; D005260:Female; D006801:Humans; D007022:Hypotension / Q000188:drug therapy* / Q000209:etiology; D007275:Injections, Intravenous; D007530:Isoflurane; D008297:Male; D010656:Phenylephrine / Q000008:administration & dosage*; D011187:Posture / Q000502:physiology*; D011446:Prospective Studies; D016277:Ventricular Function, Left / Q000187:drug effects*
D010656:Phenylephrine; D007530:Isoflurane