Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, Pennsylvania, United States.
Pulmonary Division, Heart Institute (InCor), University of São Paulo, São Paulo, Brazil.
J Appl Physiol (1985). 2023 Sep 1;135(3):500-507. doi: 10.1152/japplphysiol.00130.2023. Epub 2023 Jul 13.
Management of acute respiratory distress syndrome (ARDS) is classically guided by protecting the injured lung and mitigating damage from mechanical ventilation. Yet the natural history of ARDS is also dictated by disruption in lung perfusion. Unfortunately, diagnosis and treatment are hampered by the lack of bedside perfusion monitoring. Electrical impedance tomography is a portable imaging technique that can estimate regional lung perfusion in experimental settings from the kinetic analysis of a bolus of an indicator with high conductivity. Hypertonic sodium chloride has been the standard indicator. However, hypertonic sodium chloride is often inaccessible in the hospital, limiting practical adoption. We investigated whether regional lung perfusion measured using electrical impedance tomography is comparable between indicators. Using a swine lung injury model, we determined regional lung perfusion (% of total perfusion) in five pigs, comparing 12% sodium chloride to 8.4% sodium bicarbonate across stages of lung injury and experimental conditions (body position, positive end-expiratory pressure). Regional lung perfusion for four lung regions was determined from maximum slope analysis of the indicator-based impedance signal. Estimates of regional lung perfusion between indicators were compared in the lung overall and within four lung regions. Regional lung perfusion estimated with a sodium bicarbonate indicator agreed with a hypertonic sodium chloride indicator overall (mean bias 0%, limits of agreement -8.43%, 8.43%) and within lung quadrants. The difference in regional lung perfusion between indicators did not change across experimental conditions. Sodium bicarbonate may be a comparable indicator to estimate regional lung perfusion using electrical impedance tomography. Electrical impedance tomography is an emerging tool to measure regional lung perfusion using kinetic analysis of a conductive indicator. Hypertonic sodium chloride is the standard agent used. We measured regional lung perfusion using another indicator, comparing hypertonic sodium chloride to sodium bicarbonate in an experimental swine lung injury model. We found strong agreement between the two indicators. Sodium bicarbonate may be a comparable indicator to measure regional lung perfusion with electrical impedance tomography.
急性呼吸窘迫综合征（ARDS）的管理通常通过保护受损的肺和减轻机械通气造成的损伤来指导。然而，ARDS 的自然病程也受到肺灌注紊乱的影响。不幸的是，由于缺乏床边灌注监测，诊断和治疗受到阻碍。电阻抗断层成像（EIT）是一种便携式成像技术，可以通过对高导电性指示剂的动力分析来估计实验环境中的区域性肺灌注。高渗氯化钠一直是标准指示剂。然而，高渗氯化钠在医院中通常无法获得，限制了实际应用。我们研究了使用电阻抗断层成像测量的区域性肺灌注是否在指示剂之间具有可比性。使用猪肺损伤模型，我们在 5 头猪中比较了 12%氯化钠和 8.4%碳酸氢钠，在肺损伤的不同阶段和实验条件（体位、呼气末正压）下比较了两种指示剂。通过对基于指示剂的阻抗信号的最大斜率分析来确定四个肺区的区域性肺灌注（总灌注的%）。在整个肺和四个肺区内部比较了两种指示剂之间的区域性肺灌注估计值。碳酸氢钠指示剂估计的区域性肺灌注与高渗氯化钠指示剂总体上一致（平均偏差 0%，一致性界限-8.43%，8.43%），并且在肺象限内也一致。两种指示剂之间的区域性肺灌注差异在实验条件下没有变化。碳酸氢钠可能是一种可比较的指示剂，可用于使用电阻抗断层成像估计区域性肺灌注。电阻抗断层成像是一种新兴工具，可通过对导电指示剂的动力学分析来测量区域性肺灌注。高渗氯化钠是常用的标准试剂。我们使用另一种指示剂测量了区域性肺灌注，在实验性猪肺损伤模型中比较了高渗氯化钠和碳酸氢钠。我们发现两种指示剂之间具有很强的一致性。碳酸氢钠可能是一种可与电阻抗断层成像配合使用的区域性肺灌注测量的可比指示剂。
