Manecke G R, Nemirov M A, Bicker A A, Adsumelli R N, Poppers P J
Department of Anesthesiology, University Medical Center, State University of New York at Stony Brook, 11794-8480, USA.
Anesth Analg. 1999 Feb;88(2):263-7. doi: 10.1097/00000539-199902000-00007.
Although continuous auscultation has been used during surgery as a monitor of cardiac function for many years, the effect of anesthetics on heart sounds has never been quantified. We determined the root mean squared amplitude and frequency characteristics (peak frequency, spectral edge, and power ratios) of the first (S1) and second (S2) heart sounds in 19 healthy children during induction of anesthesia with halothane. In all patients, halothane decreased the amplitude of S1 (R2 = 0.87 +/- 0.12) and S2 (R2 = 0.66 +/- 0.33) and the high-frequency components (>80 Hz) of these sounds. These changes were clearly audible and preceded decreases in heart rate and blood pressure. The spectral edge decreased for S1 in 18 patients (R2 = 0.73 +/- 0.24) and for S2 in 13 patients (R2 = 0.58 +/- 0.25). Peak frequency did not change. The rapidity with which myocardial depression and its associated changes in heart sound characteristics occurred confirms that continuous auscultation of heart sounds is a useful clinical tool for hemodynamic monitoring of anesthetized infants and children.
Heart sound characteristics can be used to monitor cardiac function during halothane anesthesia in children. The changes occur rapidly and precede noticeable changes in heart rate and blood pressure.
尽管多年来连续听诊一直被用于手术中作为心脏功能的监测手段，但麻醉药对心音的影响从未被量化过。我们测定了19名健康儿童在氟烷麻醉诱导期间第一心音（S1）和第二心音（S2）的均方根振幅及频率特征（峰值频率、频谱边缘和功率比）。在所有患者中，氟烷降低了S1（R2 = 0.87±0.12）和S2（R2 = 0.66±0.33）的振幅以及这些心音的高频成分（>80 Hz）。这些变化清晰可闻，且先于心率和血压的下降。18名患者的S1频谱边缘降低（R2 = 0.73±0.24），13名患者的S2频谱边缘降低（R2 = 0.58±0.25）。峰值频率未改变。心肌抑制及其相关的心音特征变化出现的速度证实，连续听诊心音是麻醉婴幼儿和儿童血流动力学监测的一种有用的临床工具。
心音特征可用于监测儿童氟烷麻醉期间的心脏功能。这些变化出现迅速，且先于心率和血压的明显变化。
