Article: Okubo M, Komukai S, Izama J, et. al. Association of Advanced Airway Insertion Timing and Outcomes After Out-of-Hospital Cardiac Arrest. Ann Emerg Med. 2021;79(2):118-131.
Objective: To evaluate the association between the timing of initial advanced airway insertion and patient outcomes (primary outcomes, survival to hospital discharge and secondary outcomes, favorable neurologic status at hospital discharge) after out-of-hospital cardiac arrest in Pragmatic Airway Resuscitation Trial (PART).
Background: Airway insertion in the setting of cardiac arrest is controversial because while intubation provides a protected airway with efficient delivery of oxygen, it will increase intrathoracic pressure and result in decreased venous return.1,2,3 Currently, the International Liaison Committee on Resuscitation’s (ILCOR) Advanced Life Support task force does not have a recommendation for optimal timing of advanced airway management.5 ILCOR performed a systematic review and concluded that there is insufficient research concerning this issue.4
The Pragmatic Airway Resuscitation Trial (PART) studied laryngeal tube use versus endotracheal intubation and found better outcomes (greater 72-hour survival) with laryngeal tube use in the setting of out-of-hospital cardiac arrest in adults.6
This article is a retrospective secondary analysis of the data from the PART study that will examine the timing of airway management in out-of-hospital cardiac arrest.
Inclusion Criteria
- >18 years old
- Non-traumatic etiology of out-of-hospital cardiac arrest
- Patient treated by participating EMS agencies requiring anticipated ventilatory support or advanced airway management
Exclusion Criteria
- Pregnancy
- Prisoners
- Traumatic arrest etiology
- Major bleeding or exsanguination
- Advanced airway insertion prior to EMS participation
- Pre-existing tracheostomy
Methods: This was a retrospective secondary analysis of the clinical data from the PART study. The PART study had 3,004 patients enrolled from December 2015 to November 2017, involving 27 EMS agencies in the United States. All participating agencies received EMS protocol training to standardize the training and reporting practices.
For each patient, the start time of advanced airway insertion and time of successful airway placement were recorded. The study measured the time between the arrival of advanced life support (minute 0) and time of insertion of the laryngeal device/endotracheal tube between the teeth in whole minutes.
A novel contribution of this study is that it used statistical techniques to attempt to account for resuscitation time bias, where patients who received late intervention (advanced airway placement) required a more prolonged resuscitation, resulting in worse outcomes. A propensity score of each patient was created to measure risk of intubation/laryngeal airway device placement at a given time. Each patient with similar risk was grouped together, and then outcomes were compared between those who were at risk of advanced airway placement versus patients who were not.
Then, times at different intervals were compared for the laryngeal tube insertion and first endotracheal intubation attempt.
Primary Outcomes
- Survival to discharge
Secondary Outcomes
- Favorable neurological status at hospital discharge defined as modified Rankin scale score ≤3
- 72-hour survival
Results
Laryngeal tube insertion time interval after advanced life support arrival
|
|
Survival to discharge |
Favorable neurologic status at hospital discharge |
72-hour survival |
|
0-5 minutes |
RR=1.35, 95% CI 0.53 to 3.44 |
RR=2.11, 95% CI (0.40-11.15) |
RR=1.87 95% CI (0.88-3.95) |
|
5-10 minutes |
RR=1.07, 95% CI 0.66 to 1.73 |
RR=0.95, 95% CI (0.36-2.48) |
RR=1.18 95% CI (0.85-1.63) |
|
10-15 minutes |
RR=1.17, 95% CI 0.60 to 2.31 |
RR=0.95, 95% CI (0.23-4.05) |
RR=0.94 95% CI (0.59-1.50) |
|
15-20 minutes |
RR=2.09, 95% CI 0.35 to 12.47 |
** |
RR=1.58 95% CI (0.20-12.28) |
|
>20mins |
** |
** |
** |
Endotracheal tube insertion time interval after advanced life support arrival
|
|
survival to discharge |
favorable neurologic status at hospital discharge |
72 hour survival |
|
0-5 minutes |
RR=0.50, 95% CI 0.05 to 4.87 |
RR= 1.00, 95% CI(0.07-14.35) |
RR=0.26, 95% CI (0.03-1.93) |
|
5-10 minutes |
RR=1.20, 95% CI 0.51 to 2.81 |
RR=0.60, 95% CI (0.19-1.86) |
RR=1.49, 95% CI (0.84-2.64) |
|
10-15 minutes |
RR=1.03, 95% CI 0.49 to 2.14 |
RR=0.42, 95% CI (0.08-2.17) |
RR=1.50, 95% CI (0.87-2.57) |
|
15-20 minutes |
RR=0.85, 95% CI 0.30 to 2.42 |
RR= 0.76, 95% CI (0.20-0.93) |
RR=1.20, 95% CI(0.56-2.56) |
|
>20min |
RR= 0.71, 95% CI (0.07-7.14) |
** |
RR=1.10, 95% CI (0.27-4.50) |
No significant associations were found between the first endotracheal tube or laryngeal tube insertion and time to matching for each outcome (survival to discharge, favorable neurologic status at hospital discharge, and 72-hour survival).
Strengths
- May be contradictory to previous studies showing improved outcomes with earlier intubation, but this is the first study to try to account for resuscitation bias when analyzing data.7,8
- Measured time of initial laryngeal airway device/endotracheal tube insertion, instead of time to successful insertion, so that the insertion time was not altered by other factors that are not related to study such as difficult airway anatomy, training, and experience.
Limitations
- This is a secondary analysis of a study designed to measure an entirely different effect; the combination of this and the “magic” of propensity score matching may not result in dependable analysis.
- Difficult to measure actual time of advanced airway device placement and advanced life support arrival time.
- The study did not account for the appropriate size of laryngeal airway device and endotracheal tube that was placed.
- Time to endotracheal tube insertion and time to successful endotracheal tube insertion may be different between each EMS provider since it is dependent on resuscitation practices of each agency.
- EMS agencies that were included in the study were dependent on their personal preference and ability to participate in the study. Hence, the study may be valid for agencies that can have similar capabilities.
Conclusion
- This study found no association between the timing of initial advanced airway insertion and patient outcomes (primary outcomes, survival to hospital discharge and secondary outcomes, favorable neurologic status at hospital discharge) after out-of-hospital cardiac arrest.
- The study highlights the controversy of when is the optimal time to have an advanced airway placed in out-of-hospital cardiac arrest for EMS providers.
- The timing of advanced airway placement in out-of-hospital cardiac arrest requires additional investigation to find if a specific situation or specific patient type may benefit from management of timing of advanced airway placement.
References
- Wang HE, Simeone SJ, Weaver MD, et al. Interruptions in cardiopulmonary resuscitation from paramedic endotracheal intubation. Ann Emerg Med. 2009;54:645-652.e1.
- Aufderheide TP, Lurie KG. Death by hyperventilation: a common and life-threatening problem during cardiopulmonary resuscitation. Crit Care Med. 2004;32:S345-S351.
- Aufderheide TP, Sigurdsson G, Pirrallo RG, et al. Hyperventilation-induced hypotension during cardiopulmonary resuscitation. Circulation. 2004;109:1960-1965.
- Grandfeldt A, Avis SR, Nicholson TC, et al. Advanced Airway Management During Adult Cardiac Arrest: A Systematic Review. Resuscitation. 2019;139:133-143.
- 2019 American Heart Association Focused Update on Advanced Cardiovascular Life Support: Use of Advanced Airways, Vasopressors, and Extracorporeal Cardiopulmonary Resuscitation During Cardiac Arrest.
- Wang HE, Schmicker RH, Daya MR, et al. Effect of a strategy of initial laryngeal tube insertion vs endotracheal intubation on 72-hour survival in adults with out-of-hospital cardiac arrest: A randomized clinical trial. JAMA. 2018;320:769-778.
- Izawa J, Iwami T, Gibo K, et al. Timing of advanced airway management by emergency medical services personnel following out-of-hospital cardiac arrest: A population-based cohort study. Resuscitation. 2018;128:16-23.
- Shy BD, Rea TD, Becker LJ, et al. Time to intubation and survival in prehospital cardiac arrest. Prehosp Emerg Care. 2004;8:394-399.