Galletly D C, Larsen P D
Section of Anaesthesia, Wellington School of Medicine, New Zealand.
Br J Anaesth. 1997 Jul;79(1):35-40. doi: 10.1093/bja/79.1.35.
In 20 spontaneously breathing patients undergoing minor surgical procedures under general anaesthesia, we examined the timing relationship of heart best and ventilation. Patients received propofol 2-2.5 mg kg-1 and fentanyl 1 microgram kg-1 and breathed a mixture of 1-1.5% isoflurane and 66% nitrous oxide in oxygen. We recorded ECG R wave times and the start of each inspiration. We observed that: (1) all subjects showed evidence of phase coupling in which heart beats occurred at constant phases of the ventilatory cycle; (2) there was a significant preference for whole number ratios of heart rate to ventilatory frequency; (3) phase coupling was associated frequently with quantal changes in heart rate or ventilatory frequency, or both; (4) six coupling patterns were described according to the timing relationship between the ECG R wave and start of inspiration and according to changes in the number of heart beats within each ventilatory period; (5) phase coupling was achieved primarily by transient changes in ventilatory period. Phase coupling, in concert with respiratory sinus arrhythmia, may optimize the performance of the thoracic pump, matching cardiac filling to venous return. Coupling may therefore have anaesthetic relevance in conditions of impaired cardiac performance or hypovolaemia.
在20例接受全身麻醉下小型外科手术的自主呼吸患者中，我们研究了心率与通气的时间关系。患者接受2 - 2.5毫克/千克的丙泊酚和1微克/千克的芬太尼，并吸入1 - 1.5%异氟烷和66%氧化亚氮与氧气的混合气体。我们记录了心电图R波时间和每次吸气开始时间。我们观察到：（1）所有受试者均显示出相位耦合的证据，即心跳在通气周期的固定阶段发生；（2）心率与通气频率的整数比存在显著偏好；（3）相位耦合常与心率或通气频率的定量变化或两者的变化相关；（4）根据心电图R波与吸气开始之间的时间关系以及每个通气周期内心跳次数的变化，描述了六种耦合模式；（5）相位耦合主要通过通气周期的短暂变化实现。相位耦合与呼吸性窦性心律失常协同作用，可能优化胸泵功能，使心脏充盈与静脉回流相匹配。因此，在心脏功能受损或血容量不足的情况下，耦合可能与麻醉相关。
