Kudoh I, Andoh T, Doi H, Kaneko K, Okutsu Y, Okumura F
Department of Anesthesiology, Yokohama City University School of Medicine, Japan.
Chest. 1992 Feb;101(2):530-3. doi: 10.1378/chest.101.2.530.
The effect of continuous positive-pressure ventilation (CPPV) on extravascular lung water volume has been investigated, but there is only one report which studied the effect of continuous negative extrathoracic pressure ventilation (CNETPV). The effect of CNETPV on central blood volume (CBV) has not been studied. Changes in intrathoracic pressure by CNETPV may alter lung water volume and CBV. In this study the effects of CNETPV on lung water volume and CBV were compared with those of intermittent positive-pressure ventilation (IPPV) and CPPV in dogs with pulmonary edema induced by oleic acid. Nine mongrel dogs were anesthetized and given oleic acid at 0.06 ml/kg intravenously to induce pulmonary edema; CNETPV was applied with a cuirass and a negative thoracic pressure ventilator (Kimura OKT-100) for 1 h. Extravascular lung water volume (as extravascular thermal volume [EVTV]) and CBV were estimated with the double-indicator dilution method using thermal-sodium; PEEP and continuous negative extrathoracic pressure were matched to produce the same increments in FRC. The EVTV increased during CNETPV but did not change during CPPV. The CBV decreased during CPPV but did not change during CNETPV. An increase of transmural pulmonary microvascular pressure was thought to be one of the reasons for the increase in EVTV with CNETPV.
持续正压通气（CPPV）对血管外肺水容量的影响已得到研究，但仅有一篇报告研究了持续胸外负压通气（CNETPV）的影响。CNETPV对中心血容量（CBV）的影响尚未得到研究。CNETPV引起的胸内压变化可能会改变肺水容量和CBV。在本研究中，将CNETPV对肺水容量和CBV的影响与间歇正压通气（IPPV）和CPPV在油酸诱导的肺水肿犬中的影响进行了比较。9只杂种犬麻醉后静脉注射0.06 ml/kg油酸以诱导肺水肿；使用胸甲和负压呼吸机（木村（木村OKT - 100进行1小时的CNETPV。使用热钠双指示剂稀释法估计血管外肺水容量（作为血管外热容量[EVTV]）和CBV；使呼气末正压（PEEP）和持续胸外负压相匹配，以使功能残气量（FRC）产生相同的增加。CNETPV期间EVTV增加，但CPPV期间未变化。CPPV期间CBV降低，但CNETPV期间未变化。跨壁肺微血管压力增加被认为是CNETPV导致EVTV增加的原因之一。
