Ratzenhofer-Komenda B, Offner A, Ofner P, Klemen H, Prause G, Smolle-Jüttner F M, Toller W
Department of Anaesthesiology and Critical Care, University Medical School of Graz, Graz, Austria.
Acta Anaesthesiol Scand. 2007 Jan;51(1):68-73. doi: 10.1111/j.1399-6576.2006.01197.x.
Inhalation of hyperbaric oxygen (HBO) has been reported to decrease arterial oxygen tension (PaO(2)) in the early period after exposure. The current investigation aimed at evaluating whether and to what extent arterial blood gases were affected in mechanically ventilated intensive care patients within 6 h after HBO treatment.
Arterial blood gases were measured in 11 ventilated subjects [nine males, two females, synchronized intermittent mandatory ventilation (SIMV) mode] undergoing HBO therapy for necrotizing soft tissue infection (seven patients), burn injury (two patients), crush injury (one patient) and major abdominal surgery (one patient). Blood gases were obtained with the patients in the supine position under continuous analgesia and sedation before the hyperbaric session (baseline), during isopression, after decompression, after each transport, and 1, 2, 3 and 6 h after exposure. Heart rates and blood pressures were recorded. Intensive care unit (ICU) ventilator settings remained unchanged. Transport and chamber ventilator settings were adjusted to baseline with maintenance of tidal volumes and positive end-expiratory pressure (PEEP) levels. The hyperbaric protocol consisted of 222.9 kPa (2.2 absolute atmospheres) and a 50-min isopression phase. The paired Wilcoxon's test was used.
Major findings (median values, 25%/75% quartiles) as per cent change of baseline: PaO(2) values decreased by 19.7% (7.0/31.7, P < 0.01) after 1 h and were elevated over baseline by 9.3% (1.5/13.7, P < 0.05) after 3 h. SaO(2), alveolar-arterial oxygen tension difference and PaO(2)/FiO(2) ratio behaved concomitantly. Acid-base status and carbon dioxide tension were unaffected.
Arterial oxygen tension declines transiently after HBO and subsequently improves over baseline in intensive care patients on volume-controlled mechanical ventilation. The effectiveness of other ventilation modes or a standardized recruitment manoeuvre has yet to be evaluated.
据报道，吸入高压氧（HBO）后早期动脉血氧分压（PaO₂）会降低。本研究旨在评估HBO治疗后6小时内，机械通气的重症监护患者的动脉血气是否受到影响以及影响程度如何。
对11例接受HBO治疗的机械通气患者（9例男性，2例女性，同步间歇指令通气（SIMV）模式）进行了动脉血气测量，这些患者因坏死性软组织感染（7例）、烧伤（2例）、挤压伤（1例）和腹部大手术（1例）接受治疗。在高压治疗前（基线）、等压期间、减压后、每次转运后以及暴露后1、2、3和6小时，在持续镇痛和镇静下让患者处于仰卧位时采集血气。记录心率和血压。重症监护病房（ICU）呼吸机设置保持不变。将转运和舱内呼吸机设置调整至基线水平，维持潮气量和呼气末正压（PEEP）水平。高压治疗方案包括222.9 kPa（2.2绝对大气压）和50分钟的等压期。采用配对Wilcoxon检验。
以相对于基线的变化百分比表示的主要结果（中位数，四分位数间距25%/75%）：1小时后PaO₂值下降19.7%（7.0/31.7，P<0.01），3小时后比基线升高9.3%（1.5/13.7，P<0.05）。血氧饱和度（SaO₂）、肺泡 - 动脉血氧分压差和PaO₂/吸入氧浓度（FiO₂）比值变化趋势相同。酸碱状态和二氧化碳分压未受影响。
在接受容量控制机械通气的重症监护患者中，HBO治疗后动脉血氧分压会短暂下降，随后高于基线水平。其他通气模式或标准化肺复张手法的效果还有待评估。
