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Correspondence  |   May 2002
Volatile Agents Depress Contractility in Children
Author Notes
  • Cincinnati, Ohio.
Article Information
Correspondence
Correspondence   |   May 2002
Volatile Agents Depress Contractility in Children
Anesthesiology 5 2002, Vol.96, 1273. doi:
Anesthesiology 5 2002, Vol.96, 1273. doi:
To the Editor:—
Rivenes et al.  1 have presented evidence that sevoflurane and isoflurane preserve forward output in patients with congenital heart disease. Their conclusion that cardiac output is maintained with little change in contractility with sevoflurane and isoflurane is not accurate. The data in their table 4 indicate that systemic vascular resistance decreases with both agents, whereas cardiac output and preload (left ventricular end-diastolic volume) are unchanged. This result is obtained only if contractility decreases. I used the data in table 4 of Rivenes et al.  1 to estimate end-systolic elastance (Ees) 2 for the isoflurane cases using a computer model 3 modified to simulate the characteristics of pediatric hearts. Input variables were heart rate, systemic vascular resistance, and left ventricular end-diastolic volume. The Ees required to generate the ejection fraction (mean value) from table 4 of Rivenes et al.  1 for each isoflurane case and the resulting mean arterial pressure and cardiac index are shown in table 1below.
Table 1. End-systolic Elastance as a Function of Isoflurane Concentration: Model Predictions
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Table 1. End-systolic Elastance as a Function of Isoflurane Concentration: Model Predictions
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References
Rivenes SM, Lewin MB, Stayer SA, Bent ST, Schoenig HM, McKenzie ED, Fraser CD, Andropolous DB: Cardiovascular effects of sevoflurane, isoflurane, halothane and fentanyl–midazolam in children with congenital heart disease. A nesthesiology 2001; 94: 223–9Rivenes, SM Lewin, MB Stayer, SA Bent, ST Schoenig, HM McKenzie, ED Fraser, CD Andropolous, DB
Suga H, Sagawa K, Kostiuk DP: Controls of ventricular contractility assessed by pressure-volume ratio, Emax. Cardiovasc Res 1976; 95: 582–92Suga, H Sagawa, K Kostiuk, DP
Stern RH, Rasmussen H: Left ventricular ejection: Model solution by collocation, an approximate analytical method. Comput Biol Med 1996; 26: 255–61Stern, RH Rasmussen, H
Table 1. End-systolic Elastance as a Function of Isoflurane Concentration: Model Predictions
Image not available
Table 1. End-systolic Elastance as a Function of Isoflurane Concentration: Model Predictions
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