A pilot assessment of alpha-stat vs pH-stat arterial blood gas analysis after cardiac arrest

作者：Eastwood Glenn M^*; Suzuki Satoshi; Lluch Cristina; Schneider Antoine G; Bellomo Rinaldo

来源：Journal of Critical Care, 2015, 30(1): 138-144.

DOI：10.1016/j.jcrc.2014.09.022

• Arterial blood gas
• Cardiac arrest
• Intensive care
• Hypoxemia
• Hyperoxemia
• Hypocapnia

Purpose: Resuscitated cardiac arrest (CA) patients typically receive therapeutic hypothermia, but arterial blood gases (ABGs) are often assessed after adjustment to 37 degrees C (alpha-stat) instead of actual body temperature (pH-stat). We sought to compare alpha-stat and pH-stat assessment of Pao(2) and Paco(2) in such patients.
Materials and methods: Using ABG data obtained during the first 24 hours of intensive care unit admission, we determined the impact of measured alpha vs calculated pH-stat on Pao(2) and Paco(2) on patient classification and outcomes for CA patients.
Results: We assessed 1013 ABGs from 120 CA patients with a median age of patients 66 years (interquartile range, 50-76). Median alpha-stat Pao(2) changed from 122 (95-156) to 107 (82-143) mm Hg with pH-stat and median Paco(2) from 39 (34-46) to 35 (30-41) mm Hg (both P < .001). Using the categories of hyperoxemia, normoxemia, and hypoxemia, pH-stat estimation of Pao(2) reclassified approximately 20% of patients. Using the categories of hypercapnia, normocapnia, and hypocapnia, pH-stat estimation of Paco(2) reclassified approximately 40% of patients. The mortality of patients in different Pao(2) and Paco(2) categories was similar for pH-stat and alpha-stat.
Conclusions: Using the pH-stat method, fewer resuscitated CA patients admitted to intensive care unit were classified as hyperoxemic or hypercapnic compared with alpha-stat. These findings suggest an impact of ABG assessment methodology on Pao(2), Paco(2), and patient classification but not on associated outcomes.

• 出版日期2015-2
• 单位迪肯大学