Manecke G R, Poppers P J
Department of Anesthesiology, University Medical Center, State University of New York at Stony Brook, 11794-8480, USA.
Anesth Analg. 1998 Jun;86(6):1276-9. doi: 10.1097/00000539-199806000-00027.
Although the esophageal stethoscope has been used for many years, the effect of the depth of placement on the quality of the sounds obtained has never been investigated. The amplitude and frequency characteristics of the first and second heart sound and of inspiratory and expiratory breath sounds were determined at various stethoscope depths (from the distal tip) in 17 healthy anesthetized adults. The amplitude for each type of sound varied markedly with depth. Maximal amplitude for S1 was at 34 +/- 3 cm, for S2 at 27 +/- 2 cm, for inspiratory breath sound at 28 +/- 2 cm, and for expiratory breath sound at 26 +/- 2 cm. There was a positive linear correlation between the depth of maximal amplitude of these sounds and patient height. Peak frequency, in general, did not change with depth. We conclude that investigators should measure and document depth when performing studies involving the esophageal stethoscope.
Analysis of sound from the esophageal stethoscope at various depths reveals that placement depth greatly affects the sounds. A depth of 28-32 cm is recommended for clinical use; S1, S2, and inspiratory and expiratory sounds have a high amplitude in that range.
尽管食管听诊器已使用多年，但放置深度对所获声音质量的影响从未被研究过。在17名接受麻醉的健康成年受试者中，测定了在不同听诊器深度（从远端尖端起）时第一心音、第二心音以及吸气和呼气呼吸音的幅度和频率特征。每种声音的幅度随深度变化显著。第一心音的最大幅度出现在34±3厘米处，第二心音在27±2厘米处，吸气呼吸音在28±2厘米处，呼气呼吸音在26±2厘米处。这些声音最大幅度的深度与患者身高呈正线性相关。一般来说，峰值频率不随深度变化。我们得出结论，研究人员在进行涉及食管听诊器的研究时应测量并记录深度。
对不同深度食管听诊器声音的分析表明，放置深度对声音有很大影响。临床使用建议深度为28 - 32厘米；在此范围内，第一心音、第二心音以及吸气和呼气声音的幅度较高。
