Relationship Between Supranormal Oxygen Tension and Outcome After Resuscitation From Cardiac Arrest

Abstract

Background-Laboratory and recent clinical data suggest that hyperoxemia after resuscitation from cardiac arrest is harmful; however, it remains unclear if the risk of adverse outcome is a threshold effect at a specific supranormal oxygen tension, or is a dose-dependent association. We aimed to define the relationship between supranormal oxygen tension and outcome in postresuscitation patients. Methods and Results-This was a multicenter cohort study using the Project IMPACT database (intensive care units at 120 US hospitals). Inclusion criteria were age Ͼ17 years, nontrauma, cardiopulmonary resuscitation preceding intensive care unit arrival, and postresuscitation arterial blood gas obtained. We excluded patients with hypoxia or severe oxygenation impairment. We defined the exposure by the highest partial pressure of arterial oxygen (PaO 2 ) over the first 24 hours in the ICU. The primary outcome measure was in-hospital mortality. We tested the association between PaO 2 (continuous variable) and mortality using multivariable logistic regression adjusted for patient-oriented covariates and potential hospital effects. Of 4459 patients, 54% died. The median postresuscitation PaO 2 was 231 (interquartile range 149 to 349) mm Hg. Over ascending ranges of oxygen tension, we found significant linear trends of increasing in-hospital mortality and decreasing survival as functionally independent. On multivariable analysis, a 100 mm Hg increase in PaO 2 was associated with a 24% increase in mortality risk (odds ratio 1.24 [95% confidence interval 1.18 to 1.31]. We observed no evidence supporting a single threshold for harm from supranormal oxygen tension. Conclusion-In this large sample of postresuscitation patients, we found a dose-dependent association between supranormal oxygen tension and risk of in-hospital death. (Circulation. 2011;123:2717-2722.)

Mechanical Ventilation and ARDS in the ED

“…Increasing evidence suggests excessive oxygen exposure has adverse eff ects in various conditions, such as cardiac arrest, ARDS, COPD, and acute myocardial infarction. [49][50][51][52][53] Providing an optimal environment for lung protection, however, probably requires attention to not only tidal volume, but also appropriate lung recruitment and oxygen exposure. Variables are reported as mean Ϯ SD unless indicated otherwise.…”

Efficiency of goal-directed oxygen delivery in ICU patients

“…In brain strokes recent guidelines emphasize that oxygen should only be used in strokes in the presence of hypoxaemia for the same reasons [8]. In post-resuscitation adult patients, both out of hospital and in the ICU, hyperoxia seems to be linked to a worse outcome in terms of one's neurological state and risk of death [9,10]. Neonatal Resuscitation Program guidelines recommend initial resuscitation of asphyxiated term newborns with 21% oxygen due to higher neonatal mortality with high flow oxygen [11].…”

Intensive care medicine is 60 years old: the history and future of the intensive care unit

“…7 Supranormal oxygen values are now considered harmful, although recent evidence supporting this in patients who have had a cardiac arrest is controversial. 8 We accept lower mean arterial blood pressure and cardiac output values than we did 10 years ago. [9][10][11] Patients are sedated less heavily than they were in the past, with the aim of keeping them comfortable instead of comatose, 12 and daily sedation holds are undertaken where possible.…”