Pragmatic Airway Management in Out-of-Hospital Cardiac Arrest

Airway management in out-of-hospital cardiac arrest: A systematic review and network meta-analysis

OBJECTIVES

Airway management during cardiopulmonary resuscitation is particularly important for patients with out-of-hospital cardiac arrest (OHCA). This study was performed to compare the efficacy of the most commonly used out-of-hospital airway management methods in increasing the survival to discharge in patients with OHCA.

METHODS

We screened all relevant literature from database inception to 21st January 2019 in PubMed, Web of Science, Embase, and the Cochrane Library. We included all randomized controlled trials (RCTs) of airway management for OHCA in adults (≥16 years of age) with no limitations on publication status, publication date, or language. The primary outcome was survival to discharge. The secondary outcomes were the overall airway technique success rate, return of spontaneous circulation, and survival to hospital admission.

RESULTS

Overall, from 1986 to 2018, 9 RCTs involving 13,949 patients were included in the network meta-analysis, and the efficacy of six airway management methods for patients with OHCA were compared. However, none of the results were statistically significant.

CONCLUSIONS

As the gold standard of airway management for patients with out-of-hospital cardiac arrest in most countries, endotracheal intubation (ETI) has been widely used for many years. However, our systematic review and network meta-analysis showed that ETI is no better than other methods in increasing the survival to discharge. This is not directly proportional to the various preparations required before ETI. Additional randomized controlled trials are needed to identify more effective methods and improve patients' outcome.

An oropharyngeal device for airway management of conscious and semiconscious patients: A randomized clinical trial

OBJECTIVE

No oropharyngeal devices exist for use in conscious and semiconscious trauma patients during emergency evacuation, transport, or resuscitation. We aimed to test the hypotheses that the ManMaxAirway (MMA) is better tolerated than the standard Guedel-style device in awake volunteers and that it produces a jaw thrust and improves air flow.

METHODS

This was a randomized cross-over study of healthy volunteers with either the MMA or standard device. The primary outcome of tolerability was defined as maintaining the device in place for 60 seconds. Secondary outcomes included respiratory system function and jaw thrust. Resistance to airflow through the device lumen was measured in situ and when placed in subjects in the pulmonary laboratory alone. Jaw thrust was quantified as displacement between the mandibular condyle and condylar fossa apex relative to baseline visualized with magnetic resonance imaging (MRI).

RESULTS

We enrolled 19 subjects. Of these, a convenience sample of 5 individuals was selected for MRI; the remaining individuals (n = 14) were randomized for the cross-over study. All 14 subjects were able to maintain the MMA for 60 seconds compared with 2/14 (14%) with the standard device (odds ratio, 145; 95% confidence interval, 6.3-3314). Subjects reported that the experimental device was more comfortable and its placement did not trigger the gag reflex. Airway resistance produced by the MMA in an oscillatory flow model was nearly an order of magnitude lower than that of the standard device (experimental vs standard, 8 Hz-0.092 vs 0.786 cmH20·s/L; 15 Hz-0.193 vs 1.321 cmH20·s/L). Rapid induction of the gag reflex precluded further measurements with the standard device. Forced oscillation pulmonary testing in conscious volunteers with and without the MMA demonstrated that the device decreased respiratory system resistance to airflow and reduced respiratory elastance (31% ± 8% and 44% ± 13.4%, respectively; P < 0.05). MRIs of the subjects (n = 5) with the MMA in place showed a significant jaw thrust compared with baseline (7 ± 1 mm).

CONCLUSIONS

The MMA proved well tolerated in conscious subjects, resulting in an opening of the anatomic airway and a decreased resistance to airflow.

Advanced airway management during adult cardiac arrest: A systematic review

AIM

To systematically review the literature on advanced airway management during adult cardiac arrest in order to inform the International Liaison Committee of Resuscitation (ILCOR) consensus on science and treatment recommendations.

METHODS

The review was performed according to PRISMA guidelines and registered on PROSPERO (CRD42018115556). We searched Medline, Embase, and Evidence-Based Medicine Reviews for controlled trials and observational studies published before October 30, 2018. The population included adult patients with cardiac arrest. Two investigators reviewed studies for relevance, extracted data, and assessed the risk of bias of individual studies.

RESULTS

We included 78 observational studies and 11 controlled trials. Most of the observational studies and all of the controlled trials only included patients with out-of-hospital cardiac arrest. The risk of bias for individual observational studies was overall assessed as critical or serious, with confounding and selection bias being the primary sources of bias. Three of the controlled trials, all published in 2018, were powered for clinical outcomes with two comparing a supraglottic airway to tracheal intubation and one comparing bag-mask ventilation to tracheal intubation. All three trials had some concerns regarding risk of bias primarily due to lack of blinding and variable adherence to the protocol. Clinical and methodological heterogeneity across studies, for both the observational studies and the controlled trials, precluded any meaningful meta-analyses.

CONCLUSIONS

We identified a large number of studies related to advanced airway management in adult cardiac arrest. Three recently published, large randomized trials in out-of-hospital cardiac arrest will help to inform future guidelines. Trials of advanced airway management during in-hospital cardiac arrest are lacking.

Pre-hospital advanced airway management for adults with out-of-hospital cardiac arrest: nationwide cohort study

OBJECTIVE

To determine survival associated with advanced airway management (AAM) compared with no AAM for adults with out-of-hospital cardiac arrest.

DESIGN

Cohort study between January 2014 and December 2016.

SETTING

Nationwide, population based registry in Japan (All-Japan Utstein Registry).

PARTICIPANTS

Consecutive adult patients with out-of-hospital cardiac arrest, separated into two sub-cohorts by their first documented electrocardiographic rhythm: shockable (ventricular fibrillation or pulseless ventricular tachycardia) and non-shockable (pulseless electrical activity or asystole). Patients who received AAM during cardiopulmonary resuscitation were sequentially matched with patients at risk of AAM within the same minute on the basis of time dependent propensity scores.

MAIN OUTCOME MEASURES

Survival at one month or at hospital discharge within one month.

RESULTS

Of the 310 620 patients eligible, 8459 (41.2%) of 20 516 in the shockable cohort and 121 890 (42.0%) of 290 104 in the non-shockable cohort received AAM during cardiopulmonary resuscitation. After time dependent propensity score sequential matching, 16 114 patients in the shockable cohort and 236 042 in the non-shockable cohort were matched at the same minute. In the shockable cohort, survival did not differ between patients with AAM and those with no AAM: 1546/8057 (19.2%) versus 1500/8057 (18.6%) (adjusted risk ratio 1.00, 95% confidence interval 0.93 to 1.07). In the non-shockable cohort, patients with AAM had better survival than those with no AAM: 2696/118 021 (2.3%) versus 2127/118 021 (1.8%) (adjusted risk ratio 1.27, 1.20 to 1.35).

CONCLUSIONS

In the time dependent propensity score sequential matching for out-of-hospital cardiac arrest in adults, AAM was not associated with survival among patients with shockable rhythm, whereas AAM was associated with better survival among patients with non-shockable rhythm.