van der Schrier Rutger, van Velzen Monique, Roozekrans Margot, Sarton Elise, Olofsen Erik, Niesters Marieke, Smulders Chantal, Dahan Albert
Department of Anesthesiology, Leiden University Medical Center, Leiden, Netherlands.
Department of Anesthesiology, Noordwest Ziekenhuisgroep, Alkmaar, Netherlands.
Front Toxicol. 2022 Oct 13;4:1001709. doi: 10.3389/ftox.2022.1001709. eCollection 2022.
Due the increasing need for storage of carbon dioxide (CO) more individuals are prone to be exposed to high concentrations of CO accidentally released into atmosphere, with deleterious consequences. We tested the effect of increasing CO concentrations in humans (6-12%) and rats (10-50%) at varying inhalation times (10-60 min). In humans, a continuous positive airway pressure helmet was used to deliver the gas mixture to the participants. Unrestrained rats were exposed to CO in a transparent chamber. In both species regular arterial blood gas samples were obtained. After the studies, the lungs of the animals were examined for macroscopic and microscopic abnormalities. In humans, CO concentrations of 9% inhaled for >10 min, and higher concentrations inhaled for <10 min were poorly or not tolerated due to exhaustion, anxiety, dissociation or acidosis (pH < 7.2), despite intact oxygenation. In rats, concentrations of 30% and higher were associated with CO narcosis, epilepsy, poor oxygenation and, at 50% CO, spontaneous death. Lung hemorrhage and edema were observed in the rats at inhaled concentrations of 30% and higher. This study provides essential insight into the occurrence of physiological changes in humans and fatalities in rats after acute exposure to high levels of CO. Humans tolerate 9% CO and retain their ability to function coherently for up to 10 min. These data support reconsideration of the current CO levels (<7.5%) that pose a risk to exposed individuals (<7.5%) as determined by governmental agencies to ≤9%.
由于对二氧化碳（CO）储存的需求不断增加，越来越多的人容易意外接触到意外释放到大气中的高浓度CO，从而产生有害后果。我们测试了在不同吸入时间（10 - 60分钟）下，人类（6 - 12%）和大鼠（10 - 50%）吸入浓度不断增加的CO的影响。在人类中，使用持续气道正压头盔向参与者输送混合气体。未受约束的大鼠在透明舱内暴露于CO中。在这两个物种中，均采集了常规动脉血气样本。研究结束后，检查动物的肺部是否存在宏观和微观异常。在人类中，吸入9%的CO超过10分钟，以及吸入更高浓度但少于10分钟，由于疲劳、焦虑、解离或酸中毒（pH < 7.2），尽管氧合正常，但耐受性较差或无法耐受。在大鼠中，30%及更高的浓度与CO麻醉、癫痫、氧合不良有关，在50% CO时会导致自发死亡。在吸入浓度为30%及更高的大鼠中观察到肺出血和水肿。这项研究为急性暴露于高浓度CO后人类生理变化的发生以及大鼠死亡情况提供了重要见解。人类能耐受9%的CO，并在长达10分钟内保持连贯的功能。这些数据支持重新考虑当前政府机构确定的对暴露个体构成风险的CO水平（< 7.5%），将其调整至≤ 9%。
