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The hemodynamic and cardiovascular effects of isoflurane and halothane anesthesia in children
Insights
Isoflurane anesthesia preserved myocardial function in children, unlike halothane, which caused dose-dependent cardiac depression. This study compared hemodynamic and echocardiographic effects of these anesthetics in young patients.
Area of Science:
- Anesthesiology
- Pediatric Cardiology
- Cardiovascular Physiology
Background:
- Isoflurane and halothane are common inhalation anesthetics used in pediatric surgery.
- Understanding their cardiovascular effects in children is crucial for safe anesthetic practice.
Purpose of the Study:
- To compare the hemodynamic and cardiovascular effects of isoflurane and halothane in unpremedicated children.
- To evaluate myocardial function preservation under equipotent doses of isoflurane versus halothane.
Main Methods:
- 15 ASA I children (2-7.3 years) were randomly assigned to receive isoflurane or halothane with oxygen.
- Hemodynamic (heart rate, blood pressure) and M-mode echocardiography measurements were taken at baseline and two equipotent anesthetic concentrations.
- End-tidal carbon dioxide was monitored; protocol completed before intubation.
Main Results:
- Both anesthetics caused significant blood pressure decrease, with no change in heart rate.
- Halothane significantly reduced left-ventricular shortening fraction and mean velocity of circumferential fiber shortening in a dose-dependent manner.
- Isoflururane did not significantly alter these echocardiographic measures of myocardial function.
Conclusions:
- Halothane is associated with significant myocardial depression in children.
- Isoflurane anesthesia preserves myocardial function in pediatric patients.
- Isoflurane may be a safer anesthetic choice for maintaining cardiac performance in children.
Abstract:
The hemodynamic and cardiovascular effects of isoflurane and halothane anesthesia were studied in 15 unpremedicated ASA I children using measurements of heart rate, blood pressure and M-mode echocardiography (echo). The children (ages 2 to 7.3 yr) were randomly assigned to receive either isoflurane (N = 8) or halothane (N = 7) with oxygen. End-tidal carbon dioxide concentrations (range 30-44 mmHg) were monitored throughout the study in each child. The experimental protocol was completed prior to intubation and the initiation of surgery. Within each anesthetic group, preinduction (control) hemodynamic and echo measurements were compared with measurements obtained at two sequential equipotent end-tidal anesthetic concentrations (0.74% and 2.22% isoflurane; or 0.5% and 1.5% halothane). We also compared the data of the isoflurane group with that of the halothane group at each equipotent end-tidal anesthetic concentration. Preinduction hemodynamic (heart rate, blood pressure) and echo measurements (left ventricular dimensions and function) were similar between the two anesthetic groups. With isoflurane or halothane administration, blood pressure decreased significantly, while heart rate remained essentially unchanged. The observed alterations in heart rate and blood pressure were similar in both study groups at each equipotent end-tidal anesthetic concentration. In contrast, there were marked differences in the echo measurements of the two anesthetic groups. Halothane was associated with a significant dose-dependent decrease in echo-measured left-ventricular shortening fraction and mean velocity of circumferential fiber shortening. These echo measurements were not significantly altered by isoflurane at either end-tidal anesthetic concentration. These alterations suggest halothane is associated with significant myocardial depression in normal children, while myocardial function is well preserved during isoflurane anesthesia.