新生兒使用容積預定型呼吸器時，吸氣∕呼氣時間比、壓力波型與動脈血內氣壓之間關係的探討

The Relationship between Inspiratory: Expiratory Ratio, Wave from and Oxygenation in Respiratory Therapy

呂適存(Shis-Tswan Leu)

《Acta Paediatrica Sinica》 24卷3期 (1983/09) Pp. 154-158

摘要

本研究收集了14例患有肺病疾病，需以機械式呼吸治療的病嬰。其中10例患有肺透明膜病，3例患有胎便吸入症，1例患有肺出血。研究時選用標準容積預定型嬰兒呼吸器(Bourns LS 104-105 infant ventilator)。於呼吸治療的過程中，當呼吸器的設定，達到所期望的氧氣濃度(FIO2)，呼吸次數，呼氣終末正壓(PEEP)時，首先逐漸減低“吸氣流速率”(inspiratory flow rate)，使吸氣∕呼氣時間比率(I/E ratio)逐漸增加。當I/E rartio達到1/2，1/1，2/1，4/1時，分別測定動脈血中氣壓(PaO2)。此時呼吸器所壓出的氣體力波型爲三角型波。完成全部測定後，再將呼吸器調回至原先所設定的條件，但是利用吸氣支持作用(inspriatory hold mechanism)鈕，使波型成爲方型，再將I/E ratio調節至1/2，1/1，2/1，4/1，並測量PaO2R的變化。分析此項研究結果發現：我們必需將高I/E ratio及方型壓力波型配合使用才能達到最好的PaO2效果。但是I/E ratio PaO2的效果，亦視每個病人的情況而定，過高的I/E ratio，反而可能造成血中二氧化碳過高及氧氣降低的現象，故使用時不可不慎。

並列摘要

Fourteen neonates with severe lung disease, under mechanical ventilation with volume preset infant ventilator, were studied to clarify the relationship among inspiratory/expiratory ratio, air pressure wave form and oxygenation of the infants. During the course of respiratory therapy the study was began when each patient's condition reached the following criteria: (1) FIO2 0.4 (2) respiratory rate 40/min (3) PEEP 4cm H2O (4) effective tidal volume 10 ml/kg. Initially the inspiratery/expiratory ratio was adjusted by changing inspiratory flow rate alone in order to get a triangle pressure wave. Blood gases were measured and recorded at the I/E ratios of 1/2, 1/1, 2/1, and 4/1. Then the inspiratory hold mechanism was applied, but inspiratory flow rate was kept constant. The air pressure wave was square form at this time. The I/E ratios were adjusted to 1/2, 1/1, 2/1, 4/1 subsequently and blood gases were measured and recorded again. It is concluded that the best oxygenation were obtained with a combination of respiratory settings to produce a high I/E ratio and a square air pressure wave. The beneficial effect of this form of therapy although varied according to individual infant's condition; an excessive high ratio may produce hypercapnea and hypoxemia.

並列關鍵字

inspiratroy/expiratory ratio ； air pressure ； oxygenation ； mechanical ventilation