Høiseth Lars Ø, Hisdal Jonny, Hoff Ingrid E, Hagen Ove A, Landsverk Svein A, Kirkebøen Knut A
1Faculty of Medicine, University of Oslo, Oslo, Norway. 2Department of Anesthesiology, Oslo University Hospital, Oslo, Norway. 3Section of Vascular Investigations, Oslo University Hospital, Oslo, Norway. 4Norwegian Air Ambulance Foundation, Drøbak, Norway.
Crit Care Med. 2015 Apr;43(4):747-56. doi: 10.1097/CCM.0000000000000766.
Tissue oxygen saturation and peripheral perfusion index are proposed as early indirect markers of hypovolemia in trauma patients. Hypovolemia is associated with increased sympathetic nervous activity. However, many other stimuli, such as pain, also increase sympathetic activity. Since pain is often present in trauma patients, its effect on the indirect measures of hypovolemia needs to be clarified. The aim of this study was, therefore, to explore the effects of hypovolemia and pain on tissue oxygen saturation (measurement sites: cerebral, deltoid, forearm, and thenar) and finger photoplethysmographic perfusion index.
Experimental study.
University hospital clinical circulation and research laboratory.
Twenty healthy volunteers.
Central hypovolemia was induced with lower body negative pressure (-60 mm Hg) and pain by the cold pressor test (ice water exposure). Interventions were performed in a 2×2 fashion with the combination of lower body negative pressure or not (normovolemia), and ice water or not (sham). Each subject was thus exposed to four experimental sequences, each lasting for 8 minutes.
Measurements were averaged over 30 seconds. For each person and sequence, the minimal value was analyzed. Tissue oxygenation in all measurement sites and finger perfusion index were reduced during hypovolemia/sham compared with normovolemia/sham. Tissue oxygen saturation (except cerebral) and perfusion index were reduced by pain during normovolemia. There was a larger reduction in tissue oxygenation (all measurement sites) and perfusion index during hypovolemia and pain than during normovolemia and pain.
Pain (cold pressor test) reduces tissue oxygen saturation in all measurement sites (except cerebral) and perfusion index. In the presence of pain, tissue oxygen saturation and perfusion index are further reduced by hypovolemia (lower body negative pressure, -60 mm Hg). Thus, pain must be considered when evaluating tissue oxygen saturation and perfusion index as markers of hypovolemia in trauma patients.
组织氧饱和度和外周灌注指数被提议作为创伤患者低血容量的早期间接指标。低血容量与交感神经活动增加有关。然而，许多其他刺激因素，如疼痛，也会增加交感神经活动。由于创伤患者常伴有疼痛，其对低血容量间接指标的影响需要阐明。因此，本研究的目的是探讨低血容量和疼痛对组织氧饱和度（测量部位：大脑、三角肌、前臂和鱼际）及手指光电容积脉搏波灌注指数的影响。
实验研究。
大学医院临床循环与研究实验室。
20名健康志愿者。
通过下体负压（-60 mmHg）诱导中枢性低血容量，通过冷加压试验（暴露于冰水中）诱导疼痛。干预措施采用2×2方式，即下体负压与否（血容量正常）及冰水与否（假刺激）的组合。因此，每位受试者接受四个实验序列，每个序列持续8分钟。
测量值取30秒的平均值。对每个人和每个序列的最小值进行分析。与血容量正常/假刺激相比，低血容量/假刺激期间所有测量部位的组织氧合及手指灌注指数均降低。血容量正常时，疼痛会降低组织氧饱和度（大脑除外）和灌注指数。与血容量正常和疼痛时相比，低血容量和疼痛时组织氧合（所有测量部位）和灌注指数的降低幅度更大。
疼痛（冷加压试验）会降低所有测量部位（大脑除外）的组织氧饱和度和灌注指数。在存在疼痛的情况下，低血容量（下体负压，-60 mmHg）会进一步降低组织氧饱和度和灌注指数。因此，在评估创伤患者组织氧饱和度和灌注指数作为低血容量指标时，必须考虑疼痛因素。
