In Vitro Effects of Propofol on Gravid Human Myometrium

The aim of this study was to evaluate the direct effect of propofol (di-isopropyl phenol) on the contractile properties of gravid human uterine muscle. Six specimens of uterine muscle were obtained from term parturients undergoing elective lower segment caesarean section. Small strips (1 × 2 x 12 mm) of muscle were prepared and suspended in an organ bath containing oxygenated Kreb's solution at 36.5°C. Following preparation, spontaneous regular contractions developed at a rate of one contraction every six to 10 minutes. Force of contraction was recorded continuously using an isometric tension transducer. Following baseline measurements, propofol was introduced into the bath at concentrations corresponding to 2 /μg/ml, 5 /μg/ml and 8 /μg/ml. The specimens were also exposed to intralipid in concentrations equivalent to that found in the 8 μ/ml solution of propofol to determine whether this additive influenced uterine contractility. Contractility (defined as area under the tension/time curve) was decreased to 89 ± 6.5% of control at 2 μg/ml 53±4.3% at 5 μ/ml and 45 ± 4.1% at 8 μg/ml. This decrease in contractility was statistically significant at concentrations >2 μg/ml. Intralipid did not significantly affect uterine contractility. The results of this study show that propofol decreases isolated human uterine muscle contractility in a dose-dependent manner.