Capellier G, Beuret P, Clement G, Depardieu F, Ract C, Regnard J, Robert D, Barale F
Service de réanimation médicale, CHU, Besançon, France.
Intensive Care Med. 1998 May;24(5):422-8. doi: 10.1007/s001340050590.
To search for a threshold of pulmonary oxygen toxicity in patients with acute respiratory failure.
Retrospective study over a 10-year period.
Three intensive care units of two university hospitals.
Seventy-four patients with acute respiratory failure ventilated continuously with a FIO2 > or = 0.9 for at least 48 h were selected.
Information regarding status, scoring, diagnosis and therapeutic interventions upon admission and ICU course were extracted from the patients' charts.
We found that total exposure [mean (standard error of the mean)] to a FIO2 of 0.9 (TE 90) or more was 5.6 (1.1) days in the 17 survivors (S) versus 5.9 (0.5) days in the 57 non-survivors (D) (NS). Total exposure time to a FIO2 more than 0.5 (TE 50) was 16.5 (2.6) days in S and 11.2 (1) days in D (p < 0.05). The PaO2/FIO2 ratio became significantly higher in S only 5 days after beginning FIO2 of 0.9 or more. Hypoxemia was not frequent at the time of death, whereas in 70% of the non-survivors there were at least three organ failures in the last 48 h. In univariate analysis, the duration of exposure to FIO2 of 0.9 or more was not different in survivors and non-survivors, and the average total duration of exposure to FIO2 of more than 0.5 was even longer in survivors. In multivariate analysis, exposure shorter than 10 days to FIO2 more than 0.5 and exposure longer than 4 days to a FIO2 of 0.9 or more were significantly associated with death. However, despite a larger exposure to a FIO2 of 0.9 or more during the last 5 years of the study, the trend moved towards a higher survival rate during this period compared with the first 5 years of the study.
Thus, our data provide circumstantial evidence that the lungs of patients with acute respiratory failure might exhibit some relative resistance to prolonged oxygen exposure. Therefore, it might be worthwhile carrying out a prospective study of different FIO2 strategies in such patients.
探寻急性呼吸衰竭患者肺氧中毒的阈值。
为期10年的回顾性研究。
两家大学医院的三个重症监护病房。
选取74例急性呼吸衰竭患者，这些患者持续接受FiO₂≥0.9的通气治疗至少48小时。
从患者病历中提取入院时及重症监护病房病程中的状态、评分、诊断及治疗干预信息。
我们发现，17例存活者（S组）中，FiO₂为0.9（TE 90）及以上的总暴露时间[均值（均值标准误）]为5.6（1.1）天，而57例非存活者（D组）为5.9（0.5）天（无显著差异）。FiO₂大于0.5（TE 50）的总暴露时间，S组为16.5（2.6）天，D组为11.2（1）天（p<0.05）。仅在开始FiO₂≥0.9治疗5天后，S组的PaO₂/FiO₂比值显著升高。死亡时低氧血症并不常见，而70%的非存活者在最后48小时内至少出现了三个器官功能衰竭。单因素分析中，存活者和非存活者FiO₂≥0.9的暴露时长无差异，存活者FiO₂大于0.5的平均总暴露时长甚至更长。多因素分析中，FiO₂大于0.5时暴露短于10天以及FiO₂≥0.9时暴露长于4天与死亡显著相关。然而，尽管在研究的最后5年中FiO₂≥0.9的暴露更多，但与研究的前5年相比，这一时期的存活率呈上升趋势。
因此，我们的数据间接证明，急性呼吸衰竭患者的肺可能对长时间吸氧表现出一定的相对耐受性。所以，对这类患者开展不同FiO₂策略的前瞻性研究或许是值得的。
