Association between low pH and unfavorable neurological outcome among out-of-hospital cardiac arrest patients treated by extracorporeal CPR: a prospective observational cohort study in Japan

• Main Authors: Yohei Okada, Takeyuki Kiguchi, Taro Irisawa, Kazuhisa Yoshiya, Tomoki Yamada, Koichi Hayakawa, Kazuo Noguchi, Tetsuro Nishimura, Takuya Ishibe, Yoshiki Yagi, Masafumi Kishimoto, Hiroshi Shintani, Yasuyuki Hayashi, Taku Sogabe, Takaya Morooka, Haruko Sakamoto, Keitaro Suzuki, Fumiko Nakamura, Norihiro Nishioka, Tasuku Matsuyama, Junya Sado, Satoshi Matsui, Takeshi Shimazu, Kaoru Koike, Takashi Kawamura, Tetsuhisa Kitamura, Taku Iwami, on behalf of the CRITICAL Study Group Investigators
• Format: Article
• Language: English
• Published: BMC 2020-05-01
• Series: Journal of Intensive Care
• Subjects: Extracorporeal membrane oxygenation (ECMO); Percutaneous cardiopulmonary support (PCPS); Ventricular fibrillation; Extracorporeal life support; Blood gas assessment
• Online Access: http://link.springer.com/article/10.1186/s40560-020-00451-6

Abstract Background We aimed to identify the association of pH value in blood gas assessment with neurological outcome among out-of-hospital cardiac arrest (OHCA) patients treated by extracorporeal cardiopulmonary resuscitation (ECPR). Methods We retrospectively analyzed the database of a multicenter prospective observational study on OHCA patients in Osaka prefecture, Japan (CRITICAL study), from July 1, 2012 to December 31, 2016. We included adult OHCA patients treated by ECPR. Patients with OHCA from external causes such as trauma were excluded. We conducted logistic regression analysis to identify the odds ratio (OR) and 95% confidence interval (CI) of the pH value for 1 month favorable neurological outcome adjusted for potential confounders including sex, age, witnessed by bystander, CPR by bystander, pre-hospital initial cardiac rhythm, and cardiac rhythm on hospital arrival. Results Among the 9822 patients in the database, 260 patients were finally included in the analysis. The three groups were Tertile 1: pH ≥ 7.030, Tertile 2: pH 6.875–7.029, and Tertile 3: pH < 6.875. The adjusted OR of Tertiles 2 and 3 compared with Tertile 1 for 1 month favorable neurological outcome were 0.26 (95% CI 0.10–0.63) and 0.24 (95% CI 0.09–0.61), respectively. Conclusions This multi-institutional observational study showed that low pH value (< 7.03) before the implementation of ECPR was associated with 1 month unfavorable neurological outcome among OHCA patients treated with ECPR. It may be helpful to consider the candidate for ECPR.