Wenzel U, Wauer R R, Schmalisch G
Clinic of Neonatology, Charité-Hospital, Humboldt University, Berlin, Germany.
Intensive Care Med. 1999 Jul;25(7):705-13. doi: 10.1007/s001340050933.
The aim of the study was to test the applicability of Ventrak 1550/Capnogard 1265 (V-C) for respiratory dead space (VD) measurement and to determine anatomic (VDana), physiologic (VDphys), and alveolar dead spaces (VDalv) in ventilated neonates.
Prospective study.
Neonatal intensive care unit.
33 investigations in 22 ventilated neonates; median gestational age 34.5 weeks (range 27-41), median birthweight 2658 g (range 790-3940).
The single-breath CO2 test (SBT-CO2) and transcutaneous partial pressure of carbon dioxide (PCO2) were recorded simultaneously and VD was determined (1) automatically (V-C software), (2) by interactive analysis of the PCO2 volume plot, and (3) manually by Bohr/Enghoff equations using data obtained by V-C.
VD measurements were possible in all cases by method 3 but not possible by methods 1 and 2 in 22 of 33 investigations (67%), especially in preterm neonates, because of disturbed signals. V.Dana/kg (1.6 +/- 0.6 ml/kg, mean +/- SD), VDana/tidal volume (VT) (0.36 +/- 0.09) were lower compared to published data in spontaneously breathing infants, whereas VDphys/kg (2.3 +/- 0.9 ml/kg) and VDphys/VT (0.50 +/- 0.12) are comparable to data obtained from the literature. Five minutes after insertion of the sensor (dead space 2.6 ml) into the ventilatory circuit, the transcutaneous PCO2 rose above baseline for 3.2% (patients > 2500 g) and 5.7% (patients < 2500 g). The time necessary for one analysis was 50-60 min.
In ventilated newborns, dead space measurements were possible only in one-third by SBT-CO2, but in all cases by Bohr/Enghoff equations. Improved software could further reduce the time needed for one analysis.
本研究旨在测试Ventrak 1550/Capnogard 1265（V-C）用于测量呼吸死腔（VD）的适用性，并确定机械通气新生儿的解剖死腔（VDana）、生理死腔（VDphys）和肺泡死腔（VDalv）。
前瞻性研究。
新生儿重症监护病房。
对22例机械通气新生儿进行了33次检测；中位胎龄34.5周（范围27-41周），中位出生体重2658 g（范围790-3940 g）。
同时记录单次呼吸二氧化碳试验（SBT-CO2）和经皮二氧化碳分压（PCO2），并通过以下方式确定VD：（1）自动测定（V-C软件），（2）通过对PCO2容量图进行交互式分析，（3）使用V-C获得的数据，通过Bohr/Enghoff方程手动测定。
在所有检测中，方法3均能成功测定VD，但在33次检测中的22次（67%），尤其是早产儿，由于信号干扰，方法1和方法2无法测定VD。与已发表的自主呼吸婴儿数据相比，VDana/kg（1.6±0.6 ml/kg，平均值±标准差）和VDana/潮气量（VT）（0.36±0.09）较低，而VDphys/kg（2.3±0.9 ml/kg）和VDphys/VT（0.50±0.12）与文献数据相当。将传感器（死腔2.6 ml）插入通气回路5分钟后，经皮PCO2在体重>2500 g的患者中升高至基线以上3.2%，在体重<2500 g的患者中升高至基线以上5.7%。每次分析所需时间为50-60分钟。
在机械通气的新生儿中，仅三分之一的检测可通过SBT-CO2测定死腔，但所有检测均可通过Bohr/Enghoff方程测定。改进后的软件可进一步缩短单次分析所需时间。
