Swartz J, Cummings M, Pucci W, Biehl D
Can Anaesth Soc J. 1985 Nov;32(6):577-82. doi: 10.1007/BF03011402.
The effects of anaesthetic agents, per se, on the asphyxiated foetus are difficult to quantitate clinically. Anaesthesia is often necessary in foetal distress, however, to effect a rapid delivery. To investigate the effect of general anaesthetic agents commonly used for Caesarean section we administered these agents to 18 chronically prepared pregnant ewes with asphyxiated foetuses in utero. The foetuses were asphyxiated by partial occlusion of the umbilical cord until foetal arterial pH had decreased from 7.30 to a range of 7.08-7.13. The animals were divided into three groups: Group A which received no anaesthesia and thus served as a control, Group B which received thiopentone (3 mg . kg-1) intravenously followed by 50 per cent nitrous oxide and 0.5 per cent halothane in oxygen for 15 minutes, and Group C which received thiopentone (3 mg . kg-1) followed by one per cent halothane in oxygen for 15 minutes. Foetal cerebral, myocardial, and renal blood flows were measured by injection of radioactive microspheres after production of asphyxia and after 5 and 15 minutes of anaesthesia. General anaesthesia in both groups B and C abolished the hypertension and bradycardia produced by foetal asphyxia secondary to umbilical cord occlusion. There were no significant differences between Groups B and C in foetal pH, PCO2, or PO2. Two foetuses in the nitrous oxide group died after ten minutes of anesthesia, but the aetiology of the sudden demise is unclear. We conclude that general anaesthesia abolishes the foetal response to umbilical cord occlusion and does not improve foetal oxygenation or acid-base status.
麻醉剂本身对窒息胎儿的影响在临床上难以定量评估。然而，在胎儿窘迫时，通常需要麻醉以实现快速分娩。为了研究剖宫产常用全身麻醉剂的效果，我们将这些药物给予18只慢性制备的、子宫内胎儿窒息的妊娠母羊。通过部分阻断脐带使胎儿窒息，直至胎儿动脉血pH值从7.30降至7.08 - 7.13范围。动物被分为三组：A组不接受麻醉作为对照组，B组静脉注射硫喷妥钠（3mg·kg-1），随后在氧气中吸入50%氧化亚氮和0.5%氟烷15分钟，C组静脉注射硫喷妥钠（3mg·kg-1），随后在氧气中吸入1%氟烷15分钟。在造成窒息后以及麻醉5分钟和15分钟后，通过注射放射性微球测量胎儿脑、心肌和肾的血流量。B组和C组的全身麻醉均消除了因脐带阻塞继发胎儿窒息所产生的高血压和心动过缓。B组和C组在胎儿pH值、PCO2或PO2方面无显著差异。氧化亚氮组有两只胎儿在麻醉十分钟后死亡，但猝死的病因尚不清楚。我们得出结论，全身麻醉消除了胎儿对脐带阻塞的反应，并且并未改善胎儿的氧合或酸碱状态。
