Risk Factors for Peri-Intubation Cardiac Arrest: A Systematic Review and Meta Analysis

Review Author: Leila Bond, MD

Introduction / background / abstract:

This study is a meta-analysis of the risk factors for peri-intubation cardiac arrest (PICA), a term which is typically considered to apply to cardiac arrest that occurs within 5 to 60 minutes after intubation. The authors found that of the 28,963 patients included in the study who required intubation, 431 of them subsequently suffered cardiac arrest, making this study’s incidence rate for PICA 2.1%. There are several risk factors generally associated with PICA, such as pre-intubation hypotension and/or hypoxemia; multiple intubation attempts; poor overall patient condition, including higher BMI, higher shock index, and indication for intubation; intubation within one hour of nursing shift change; and the use of some induction medications such as succinylcholine. This study is meant to compare the statistical significance of these risk factors to quantify their actual relevance to clinical practice and aid clinicians in determining how to handle different patients who may require intubation.

Study design / Materials and methods:

This study includes data from 8 articles that meet these inclusion criteria:

·      Study design of randomized clinical trial, prospective or retrospective cohort study, or a case-control study

·      Related to analyzing risk factors for PICA in patients over the age of 14 years

Of the 3,602 articles found in the authors’ initial database search, 3,594 articles were left out due to meeting these exclusion criteria:

·      Patients suffered pre-intubation cardiac arrests, including out-of-hospital cardiac arrests

·      Case reports or case series

·      Animal studies

·      Pediatric setting (pediatric ED or pediatric ICU

·      Out-of-hospital setting

·      Research subjects repeated within the study

The authors analyzed four risk factors that were studied often in the included articles: pre-intubation hypotension, pre-intubation hypoxemia, multiple intubation attempts, and the use of succinylcholine for induction. Their goal was to determine the strength of the evidence behind each factor being a significant risk for PICA.

Challenges and limitations of this study:

·      Of the 8 included articles, 7 articles were “rated as having a risk of bias owing to the unclear measurement of prognostic factor and the lack of adjustment for other prognostic factors.”

·      The patients in each of the included studies had a wide variety of indications for intubation, and it might be useful to compare the significance of each risk factor within cohorts based on different indications for intubation (such as trauma, myocardial infarction, acute respiratory failure, etc).

·      The articles varied in their study design; 7 were retrospective cohort or case-control studies, and 1 was a “secondary analysis of prospectively collected data”.

·      The certainty levels of the evidence for each of the risk factors analyzed in this study ranged from “moderate” to “very low”.

Results / discussion / conclusions:

The authors found that three factors appear to be significant risks for PICA:

·      Pre-intubation hypotension

o   Pooled odds ratio of 4.96 (95% C.I.: 3.75–6.57)

o   “The certainty of evidence of pre-intubation hypotension being a risk factor of PICA was moderate due to the moderate risk of bias along with one upgrading factor of consistent moderate effect (each study's OR was larger than two).”

·      Pre-intubation hypoxemia

o   Pooled odds ratio of 4.43 (95% C.I.: 1.24–15.81)

o   “The certainty of evidence of pre-intubation hypoxemia being a risk factor of PICA was low due to the associated moderate risk of bias.”

·      Multiple intubation attempts

o   Pooled odds ratio of 1.88 (95% C.I.: 1.09–3.23).

o   “The certainty of evidence of two or more intubation attempts being a risk factor of PICA was very low due to the high risk of bias and inconsistency.”

The evidence against using succinylcholine in induction was inconsistent. These findings overall support the current widely accepted practices of maximizing / optimizing pre-intubation resuscitation in terms of blood pressure and oxygenation, as well as emphasize the importance of achieving a definitive airway quickly / ideally in one attempt after initiating induction for intubation. As such, the results of this study do not indicate a current need to dramatically change the way intubations are handled for the most part in emergent / critical medicine.

Citation:

Ting-Hao Yang, Shih-Chieh Shao, Yi-Chih Lee, Chien-Han Hsiao, Chieh-Ching Yen,

Risk factors for peri-intubation cardiac arrest: A systematic review and meta-analysis,

Biomedical Journal, Volume 47, Issue 3, 2024, 100656, ISSN 2319-4170, https://doi.org/10.1016/j.bj.2023.100656. (https://www.sciencedirect.com/science/article/pii/S2319417023000938)