Effect of 7.2% hypertonic saline/6% hetastarch on left ventricular contractility in anesthetized humans.
BACKGROUND
Although a positive inotropic effect of hypertonic saline has been demonstrated in isolated cardiac tissue as well as in animal preparations, no information exists about a possible positive inotropic action of hypertonic saline in humans. The aim of this investigation was to determine whether a clinically relevant positive inotropic effect can be demonstrated in humans.


METHODS
Twenty-six patients without cardiovascular disease were randomized to receive 4 ml/kg of either 7.2% hypertonic saline/6% hetastarch or 6% hetastarch (control) at a rate of 1 ml.kg-1.min-1 while under general endotracheal anesthesia. Transesophageal echocardiography was used to evaluate left ventricular function. Arterial pressure, heart rate, and left ventricular end-systolic and end-diastolic diameter, area, and wall thickness were measured immediately before and after administration of either solution. Fractional area change, end-systolic wall stress, and the area under the end-systolic pressure-length relationship curve (ESPLRarea) were calculated. ESPLRarea was used to assess left ventricular contractility.


RESULTS
Administration of hypertonic saline/hetastarch resulted in a significant decrease of mean arterial pressure and end-systolic wall stress from 77 +/- 14 (mean +/- SD) to 64 +/- 17 mmHg (P < 0.01) and from 52 +/- 14 to 32 +/- 11 10(3) dyne/cm2 (P > 0.01), respectively. End-diastolic area and fractional area change increased from 16.5 +/- 2.9 to 21.7 +/- 3.3 cm2 (P < 0.01) and from 0.53 +/- 0.07 to 0.70 +/- 0.06 (P < 0.01), respectively, whereas there was only a minor change of ESPLRarea from 38 +/- 13 to 44 +/- 13 mmHg.cm (P < 0.05).


CONCLUSIONS
The apparent improvement of left ventricular systolic function in response to hypertonic saline/hetastarch is caused mainly by the combined effect of increased left ventricular preload and reduced left ventricular afterload. A possible positive inotropic action of hypertonic saline/hetastarch is not likely to be clinically relevant.
Goertz
A W
AW
Department of Anesthesiology, University of Ulm, Germany.
Mehl
T
T
Lindner
K H
KH
Rockemann
M G
MG
Schirmer
U
U
Schwilk
B
B
Georgieff
M
M
D000328:Adult; D000768:Anesthesia, General; D005260:Female; D006801:Humans; D006895:Hydroxyethyl Starch Derivatives / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000187:drug effects*; D012462:Saline Solution, Hypertonic / Q000494:pharmacology*; D016277:Ventricular Function, Left / Q000187:drug effects*
D006895:Hydroxyethyl Starch Derivatives; D012462:Saline Solution, Hypertonic