Effects of bag-mask versus advanced airway ventilation for patients undergoing prolonged cardiopulmonary resuscitation in pre-hospital setting

Evidence-Based Guideline for Prehospital Airway Management

Airway management is a cornerstone of emergency medical care. This project aimed to create evidence-based guidelines based on the systematic review recently conducted by the Agency for Healthcare Research and Quality (AHRQ). A technical expert panel was assembled to review the evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology. The panel made specific recommendations on the different PICO (population, intervention, comparison, outcome) questions reviewed in the AHRQ review and created good practice statements that summarize and operationalize these recommendations. The recommendations address the use of ventilation with bag-valve mask ventilation alone vs. supraglottic airways vs. endotracheal intubation for adults and children with cardiac arrest, medical emergencies, and trauma. Additional recommendations address the use of video laryngoscopy and drug-assisted airway management. These recommendations, and the associated good practice statements, offer EMS agencies and clinicians an opportunity to review the available evidence and incorporate it into their airway management strategies.

Prehospital factors associated with out-of-hospital cardiac arrest outcomes in a metropolitan city: a 4-year multicenter study

BACKGROUND

Prehospital factors play a vital role in out-of-hospital cardiac arrest (OHCA) survivability, and they vary between countries and regions. We investigated the prehospital factors associated with OHCA outcomes in a single metropolitan city in the Republic of Korea.

METHODS

This study included adult medical OHCA patients enrolled prospectively, using data from the citywide OHCA registry for patients registered between 2018 and 2021. The primary outcome was survival to hospital discharge. Multivariable logistic regression analysis was conducted to determine the factors associated with the study population's clinical outcomes, adjusting for covariates. We performed a sensitivity analysis for clinical outcomes only for patients without prehospital return of spontaneous circulation prior to emergency medical service departure from the scene.

RESULTS

In multivariable logistic regression analysis, older age (odds ratio [OR] 0.96; 95% confidence interval [CI] 0.95-0.97), endotracheal intubation (adjusted odds ratio [aOR] 0.29; 95% [CIs] 0.17-0.51), supraglottic airway (aOR 0.29; 95% CI 0.17-0.51), prehospital mechanical chest compression device use (OR 0.13; 95% CI 0.08-0.18), and longer scene time interval (OR 0.96; 95% CI 0.93-1.00) were negatively associated with survival. Shockable rhythm (OR 24.54; 95% CI 12.99-42.00), pulseless electrical activity (OR 3.11; 95% CI 1.74-5.67), and witnessed cardiac arrest (OR 1.59; 95% CI 1.07-2.38) were positively associated with survival. In the sensitivity analysis, endotracheal intubation, supraglottic airway, prehospital mechanical chest compression device use, and longer scene time intervals were associated with significantly lower survival to hospital discharge.

CONCLUSIONS

Regional resuscitation protocol should be revised based on the results of this study, and modifiable prehospital factors associated with lower survival of OHCA should be improved.

Improved neurologically favorable survival after OHCA is associated with increased pre-hospital advanced airway management at the prefecture level in Japan

Out-of-hospital cardiac arrest (OHCA) has high incidence and mortality. The survival benefit of pre-hospital advanced airway management (AAM) for OHCA remains controversial. In Japan, pre-hospital AAM are performed for OHCA by emergency medical services (EMS), however the relationship between resuscitation outcomes and AAM at the prefecture level has not been evaluated. The purpose of this study was to describe the association between AAM and neurologically favorable survival (cerebral performance category (CPC) ≦2) at prefecture level. This was a retrospective, population-based study of adult OHCA patients (≧ 18) from January 1, 2014 to December 31, 2017 in Japan. We excluded patients with EMS witnessed arrests. We also only included patients that had care provided by an ELST with the ability to provided AAM and excluded cases that involved prehospital care delivered by a physician. We categorized OHCA into four quartiles (four group: G1-G4) based on frequency of pre-hospital AAM approach rate by prefecture, which is the smallest geographical classification unit, and evaluated the relationship between frequency of pre-hospital AAM approach rates and CPC ≦ 2 for each quartile. Multivariable logistic regression was used to assess effectiveness of AAM on neurologically favorable survival. Among 493,577 OHCA cases, 403,707 matched our inclusion criteria. The number of CPC ≦ 2 survivors increased from G1 to G4 (p for trend < 0.001). In the adjusted multivariable regression, higher frequency of pre-hospital AAM approach was associated with CPC ≦ 2 (p < 0.001). High prefecture frequency of pre-hospital AAM approach was associated with neurologically favorable survival (CPC ≦ 2) in OHCA.

Prehospital Airway Management: A Systematic Review

Objective: To assess comparative benefits and harms across three airway management approaches (bag valve mask [BVM], supraglottic airway [SGA], and endotracheal intubation [ETI]) used by prehospital emergency medical services (EMS) to treat patients with trauma, cardiac arrest, or medical emergencies, and how they differ based on techniques and devices, EMS personnel and patient characteristics. Data sources: We searched electronic citation databases (Ovid® MEDLINE®, CINAHL®, the Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews, and Scopus®) from 1990 to September 2020. Review methods: We followed Agency for Healthcare Research and Quality Effective Health Care Program Methods guidance. Outcomes included mortality, neurological function, return of spontaneous circulation (ROSC), and successful advanced airway insertion. Meta-analyses using profile-likelihood random effects models were conducted, with analyses stratified by study design, emergency type, and age. Results: We included 99 studies involving 630,397 patients. We found few differences in primary outcomes across airway management approaches. For survival, there was no difference for BVM versus ETI or SGA in adult and pediatric patients with cardiac arrest or trauma. For neurological function, there was no difference for BVM versus ETI and SGA versus ETI in pediatric patients with cardiac arrest. There was no difference in BVM versus ETI in adults with cardiac arrest, but improved neurological function with BVM or ETI versus SGA. There was no difference in ROSC for patients with cardiac arrest for BVM versus ETI or SGA in adults and pediatrics, or SGA versus ETI in pediatrics. There was higher frequency of ROSC in adults with SGA versus ETI. For successful advanced airway insertion, there was higher first-pass success with SGA versus ETI for all patients except adult medical patients (no difference), and no difference in overall success using SGA versus ETI in adults. Conclusions: The currently available evidence does not indicate benefits of more invasive airway approaches based on survival, neurological function, ROSC, or successful airway insertion. Strength of evidence was low or moderate; most included studies were observational. This supports the need for high-quality randomized controlled trials to advance clinical practice and EMS education and policy, and improve patient-centered outcomes.

A review of ventilation in adult out-of-hospital cardiac arrest

Out-of-hospital cardiac arrest continues to be a devastating condition despite advances in resuscitation care. Ensuring effective gas exchange must be weighed against the negative impact hyperventilation can have on cardiac physiology and survival. The goals of this narrative review are to evaluate the available evidence regarding the role of ventilation in out-of-hospital cardiac arrest resuscitation and to provide recommendations for future directions. Ensuring successful airway patency is fundamental for effective ventilation. The airway management approach should be based on professional skill level and the situation faced by rescuers. Evidence has explored the influence of different ventilation rates, tidal volumes, and strategies during out-of-hospital cardiac arrest; however, other modifiable factors affecting out-of-hospital cardiac arrest ventilation have limited supporting data. Researchers have begun to explore the impact of ventilation in adult out-of-hospital cardiac arrest outcomes, further stressing its importance in cardiac arrest resuscitation management. Capnography and thoracic impedance signals are used to measure ventilation rate, although these strategies have limitations. Existing technology fails to reliably measure real-time clinical ventilation data, thereby limiting the ability to investigate optimal ventilation management. An essential step in advancing cardiac arrest care will be to develop techniques to accurately and reliably measure ventilation parameters. These devices should allow for immediate feedback for out-of-hospital practitioners, in a similar way to chest compression feedback. Once developed, new strategies can be established to guide out-of-hospital personnel on optimal ventilation practices.

Bag-Valve Mask versus Endotracheal Intubation in Out-of-Hospital Cardiac Arrest on Return of Spontaneous Circulation: A National Database Study

Background

Out-of-hospital cardiac arrest is the main issue for pre-hospital emergency care. There are several airway managements during the out-of-hospital cardiopulmonary resuscitation (CPR) such as endotracheal intubation (ETI) or alternative airway device: bag-valve mask (BVM). Data comparing both methods showed inconclusive results on survival and limited results on CPR outcome. This study aimed to add additional results on comparing the ETI and BVM in cardiac arrest outside hospitals; focused on the CPR outcome.

Methods

This study was a retrospective, analytical study. The inclusion criteria were adult patients (age of 18 years or over) with out-of-hospital cardiac arrest, who received emergency life support, and received either BVM or ETI. Data were retrieved from the Information Technology of Emergency Medical Service. The outcome was a return of spontaneous circulation (ROSC).

Results

During the study period, there were 1070 patients with out-of-hospital cardiac arrest who met the study criteria. Of those, 800 patients (74.77%) received BVM, while the other 270 patients (25.23%) received ETI. There were five significant factors between both groups including mean distance to scene, proportions of response time less than 8 mins, defibrillation, intravenous fluid administration, and adrenaline administration. There was no significant difference on the outcome: ROSC. The BVM group had slightly higher rate of ROSC than the ETI group (19.63% vs 15.56%; p value 0.148).

Conclusion

The BVM and ETI had comparable ROSC rate for out-of-hospital cardiac arrest victims. However, the study population of the BVM group had less severe conditions and received faster treatment than the ETI group.

Location of arrest and effect of prehospital advanced airway management after emergency medical service-witnessed out-of-hospital cardiac arrest: nationwide observational study

OBJECTIVES

To investigate the association of prehospital advanced airway management (AAM) on outcomes of emergency medical service (EMS)-witnessed out-of-hospital cardiac arrest (OHCA) according to the location of arrest.

METHODS

We evaluated a Korean national OHCA database from 2012 to 2016. Adults with EMS-witnessed, non-traumatic OHCA were included. Patients were categorised into four groups according to whether prehospital AAM was conducted (yes/no) and location of arrest ('at scene' or 'in the ambulance'). The primary outcome was discharge with good neurological recovery (cerebral performance category 1 or 2). Multivariable logistic regression analysis was conducted to evaluate the association between AAM and outcome according to the location of arrest.

RESULTS

Among 6620 cases, 1425 (21.5%) cases of arrest occurred 'at the scene', and 5195 (78.5%) cases of arrest occurred 'in an ambulance'. Prehospital AAM was performed in 272 (19.1%) OHCAs occurring 'at the scene' and 645 (12.4%) OHCAs occurring 'in an ambulance'. Patients with OHCA in the ambulance who had prehospital AAM showed the lowest good neurological recovery rate (6.0%) compared with OHCAs in the ambulance with no AAM (8.9%), OHCA at scene with AAM (10.7%) and OHCA at scene with no AAM (7.7%). For OHCAs occurring in the ambulance, the use of AAM had an adjusted OR of 0.67 (95% CI 0.45 to 0.98) for good neurological recovery.

CONCLUSION

Our data show no benefit of AAM in patients with EMS-witnessed OHCA. For patients with OHCA occurring in the ambulance, AAM was associated with worse clinical outcome.

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.

Effect of National Implementation of Telephone CPR Program to Improve Outcomes from Out-of-Hospital Cardiac Arrest: an Interrupted Time-Series Analysis

BACKGROUND

In cardiac arrest, the survival rate increases with the provision of bystander cardiopulmonary resuscitation (CPR), of which the initial response and treatment are critical. Telephone CPR is among the effective methods that might increase the provision of bystander CPR. This study aimed to describe and examine the improvement of neurological outcomes in individuals with out-of-hospital acute cardiac arrest by implementing the nationwide, standardized telephone CPR program.

METHODS

Data from the emergency medical service-based cardiac arrest registry that were collected between 2009 and 2014 were used. The effectiveness of the intervention in the interrupted time-series study was determined via a segmented regression analysis, which showed the risk ratio and risk difference in good neurological outcomes before and after the intervention.

RESULTS

Of 164,221 patients, 148,403 were analyzed. However, patients with unknown sex and limited data on treatment outcomes were excluded. Approximately 64.3% patients were men, with an average age of 63.7 years. The number of bystander CPR increased by 3.3 times (95% confidence interval [CI], 3.1-3.5) after the intervention, whereas the rate of good neurological outcomes increased by 2.6 times (95% CI, 2.3-2.9 [1.6%]; 1.4-1.7). The excess number was identified based on the differences between the observed and predicted trends. In total, 2,127 cases of out-of-hospital cardiac arrest (OHCA) after the intervention period received additional bystander CPR, and 339 cases of OHCA had good neurological outcomes.

CONCLUSION

The nationwide implementation of the standardized telephone CPR program increased the number of bystander CPR and improved good neurological outcomes.

Efficacy of Manual Ventilation Techniques During Cardiopulmonary Resuscitation in Dogs

The efficacy of ventilation of dogs during cardiopulmonary resuscitation (CPR) with a tight fitting face mask or mouth-to-nose rescue breathing has not been evaluated. Twenty-four purpose bred research dogs: Dogs were randomized to be ventilated by cuffed orotracheal tube, tight fitting face mask, mouth-to-nose breathing or compressions only during CPR (n = 6 in all groups). Orotracheal tube and face mask ventilation was performed on room air. Chest compressions were performed during the experimental procedure. Arterial blood gases were performed prior to euthanasia (baseline), at 3 min and at 6 min of CPR. PaO₂ and PaCO₂ were compared for each time point and each group. There was no difference in PaO₂ or PaCO₂ between groups at baseline. At 6 min all groups had a significantly higher PaCO₂ (P ≤ 0.005) and the facemask and compression only groups had a significantly lower PaO₂ (P < 0.02) when compared to the orotracheal tube group. There was no difference between the PaO₂ of the mouth-to-nose group compared to the orotracheal tube group at 3 or 6 min. Gastric distension, regurgitation, gas leakage around the mouth, and ineffective breaths were all noted in both the face mask and mouth-to-nose group. The results of this study supports that orotracheal intubation is the preferred technique for ventilation during CPR in dogs. When orotracheal intubation is not possible, face mask ventilation or mouth-to-nose ventilation would be reasonable alternatives. When oxygen supplementation is available, face mask ventilation is likely to be superior. Appropriate training for both face mask and mouth-to-nose ventilation techniques is recommended.

Advanced airway management in out of hospital cardiac arrest: A systematic review and meta-analysis

OBJECTIVES

To assess the difference in survival and neurological outcomes between endotracheal tube (ETT) intubation and supraglottic airway (SGA) devices used during out-of-hospital cardiac arrest (OHCA).

METHODS

A systematic search of five databases was performed by two independent reviewers until September 2018. Included studies reported on (1) OHCA or cardiopulmonary resuscitation, and (2) endotracheal intubation versus supraglottic airway device intubation. Exclusion criteria (1) stimulation studies, (2) selectively included/excluded patients, (3) in-hospital cardiac arrest. Odds Ratios (OR) with random effect modelling was used. Primary outcomes: (1) return of spontaneous circulation (ROSC), (2) survival to hospital admission, (3) survival to hospital discharge, (4) discharge with a neurologically intact state.

RESULTS

Twenty-nine studies (n = 539,146) showed that overall, ETT use resulted in a heterogeneous, but significant increase in ROSC (OR = 1.44; 95%CI = 1.27 to 1.63; I² = 91%; p < 0.00001) and survival to admission (OR = 1.36; 95%CI = 1.12 to 1.66; I² = 91%; p = 0.002). There was no significant difference in survival to discharge or neurological outcome (p > 0.0125). On sensitivity analysis of RCTs, there was no significant difference in ROSC, survival to admission, survival to discharge or neurological outcome (p > 0.0125). On analysis of automated chest compression, without heterogeneity, ETT provided a significant increase in ROSC (OR = 1.55; 95%CI = 1.20 to 2.00; I² = 0%; p = 0.0009) and survival to admission (OR = 2.16; 95%CI = 1.54 to 3.02; I² = 0%; p < 0.00001).

CONCLUSIONS

The overall heterogeneous benefit in survival with ETT was not replicated in the low risk RCTs, with no significant difference in survival or neurological outcome. In the presence of automated chest compressions, ETT intubation may result in survival benefits.

Advanced Airway Type and Its Association with Chest Compression Interruptions During Out-of-Hospital Cardiac Arrest Resuscitation Attempts

OBJECTIVE

To assess interruptions in chest compressions associated with advanced airway placement during cardiopulmonary resuscitation (CPR) of out-of-hospital cardiac arrest (OHCA) victims.

METHODS

The method used was observational analysis of prospectively collected clinical and defibrillator data from 339 adult OHCA victims, excluding victims with <5 minutes of CPR. Interruptions in CPR, summarized by chest compression fraction (CCF), longest pause, and the number of pauses greater than 10 seconds, were compared between patients receiving bag valve mask (BVM), supraglottic airway (SGA), endotracheal intubation (ETI) via direct laryngoscopy (DL), and ETI via video laryngoscopy (VL). Secondary outcomes included first pass success and the effect of multiple airway attempts on CPR interruptions.

RESULTS

During the study period, paramedics managed 23 cases with BVM, 43 cases with SGA, 148 with DL, and 125 with VL. There were no statistically significant differences between the airway groups with regard to longest compression pause (BVM 18 sec [IQR 11-33], SGA 29 sec [IQR 15-65], DL 26 sec [IQR 12-59], VL 22 sec [IQR 14-41]), median number of pauses greater than 10 seconds (BVM 2 [IQR 1-3], SGA 2 [IQR 1-3], DL 2 [IQR 1-4], VL 2 [IQR 1-3]), or CCF (0.92 for all groups). However, each additional attempt following failed initial DL was associated with an increase in the risk of additional chest compression pauses (relative risk 1.29, 95% confidence interval 1.02-1.64). Such an association was not observed with additional attempts using VL or SGA. First pass success was highest with SGA (77%), followed by between DL (68%) and VL (67%); these differences were not statistically significant.

CONCLUSIONS

While summary measures of chest compression delivery did not differ significantly between airway classes in this observational study, repeated attempts following failed initial DL during cardiopulmonary resuscitation were associated with an increase in the number of pauses in chest compression delivery observed.

The role of prehospital advanced airway management on outcomes for out-of-hospital cardiac arrest patients: a meta-analysis

OBJECTIVE

The objective of this meta-analysis was to compare the benefits of prehospital advanced airway management (AAM) and basic airway management (BAM) for out-of-hospital cardiac arrest (OHCA) patients.

METHODS

Two investigators performed a systematic review of PubMed, EMBASE, and the Cochrane Database to identify all peer-reviewed articles relevant to this meta-analysis. We included all articles describing emergency medical system-treated nontraumatic OHCAs; specifically, all articles that described intervention of the prehospital AAM type were considered. The primary outcome was survival to discharge, whereas the secondary outcome was neurologic recovery after an OHCA event. For subgroup analysis, we compared the clinical outcome of endotracheal intubation (ETI), a specific type of AAM, vs BAM.

RESULTS

We reviewed 1452 studies, 10 of which satisfied all the inclusion criteria and involved 17 380 patients subjected to AAM and 67 525 subjected to BAM. Based on the full random effects model, patients who received AAM had lower odds of survival (odds ratio [OR], 0.51; 95% confidence interval [CI], 0.29-0.90) compared with BAM. Subgroup analysis for ETI vs BAM showed no significant association with respect to survival (OR, 0.44; 95% CI, 0.16-1.23). There were no significant differences in the odds of neurologic recovery between AAM and BAM (OR, 0.64; 95% CI, 0.03-1.37).

CONCLUSIONS

Our results reveal decreased survival odds for OHCA patients treated with AAM by emergency medical service personnel compared with BAM. However, the role of prehospital AAM, especially ETI, on achieving neurologic recovery remains unclear.

A review of compression, ventilation, defibrillation, drug treatment, and targeted temperature management in cardiopulmonary resuscitation

Objective:

Important studies of cardiopulmonary resuscitation (CPR) techniques influence the development of new guidelines. We systematically reviewed the efficacy of some important studies of CPR.

Data Sources:

The data analyzed in this review are mainly from articles included in PubMed and EMBASE, published from 1964 to 2014.

Study Selection:

Original articles and critical reviews about CPR techniques were selected for review.

Results:

The survival rate after out-of-hospital cardiac arrest (OHCA) is improving. This improvement is associated with the performance of uninterrupted chest compressions and simple airway management procedures during bystander CPR. Real-time feedback devices can be used to improve the quality of CPR. The recommended dose, timing, and indications for adrenaline (epinephrine) use may change. The appropriate target temperature for targeted temperature management is still unclear.

Conclusions:

New studies over the past 5 years have evaluated various aspects of CPR in OHCA. Some of these studies were high-quality randomized controlled trials, which may help to improve the scientific understanding of resuscitation techniques and result in changes to CPR guidelines.

Oxygenation, ventilation, and airway management in out-of-hospital cardiac arrest: a review

Recently published evidence has challenged some protocols related to oxygenation, ventilation, and airway management for out-of-hospital cardiac arrest. Interrupting chest compressions to attempt airway intervention in the early stages of OHCA in adults may worsen patient outcomes. The change of BLS algorithms from ABC to CAB was recommended by the AHA in 2010. Passive insufflation of oxygen into a patent airway may provide oxygenation in the early stages of cardiac arrest. Various alternatives to tracheal intubation or bag-mask ventilation have been trialled for prehospital airway management. Simple methods of airway management are associated with similar outcomes as tracheal intubation in patients with OHCA. The insertion of a laryngeal mask airway is probably associated with worse neurologically intact survival rates in comparison with other methods of airway management. Hyperoxemia following OHCA may have a deleterious effect on the neurological recovery of patients. Extracorporeal oxygenation techniques have been utilized by specialized centers, though their use in OHCA remains controversial. Chest hyperinflation and positive airway pressure may have a negative impact on hemodynamics during resuscitation and should be avoided. Dyscarbia in the postresuscitation period is relatively common, mainly in association with therapeutic hypothermia, and may worsen neurological outcome.

Supreme Laryngeal Mask Airway achieves faster insertion times than Classic LMA during chest compressions in manikins

BACKGROUND

According to the 2010 European Resuscitation Council guidelines on cardiopulmonary resuscitation (CPR), one can appreciate that the classic laryngeal mask airway (CLMA) is acceptable as an alternative airway device to endotracheal intubation for airway management in cardiac arrest victims.

OBJECTIVE

To compare a relatively new supraglottic airway device, the Supreme Laryngeal Mask Airway (SLMA), with the CLMA in a cardiac arrest scenario.

METHODS

Fifty healthcare professionals inexperienced in advanced airway management attempted to insert both airway devices in a manikin in 2 scenarios: in the first, chest compressions were not performed (non-CPR scenario), and in the second, uninterrupted chest compressions were performed (CPR scenario). The primary end points were insertion time and success rate at first attempt. The level of self-confidence of each participant was recorded.

RESULTS

SLMA achieves faster insertion times both in the non-CPR (SLMA: 10.4 ± 2.7 seconds vs CLMA: 13.4 ± 3.2 seconds, P < .05) and in the CPR scenario (SLMA: 9.9 ± 2.0 seconds Vs CLMA: 11.9 ± 2.3 seconds, P < .05). The difference between first attempt success rates was not statistically significant both in the non-CPR (SLMA: 96% vs CLMA: 90%, P = .18) and in the CPR scenario (SLMA: 98% vs CLMA: 94%, P = .32). The participants are more self-confident using SLMA instead of CLMA (P < .001) and 94% of them would prefer SLMA for future use.

CONCLUSION

SLMA could be a useful alternative to CLMA during CPR in the hands of healthcare professionals with minimal experience in airway management.

Airways in out-of-hospital cardiac arrest: systematic review and meta-analysis

OBJECTIVE

To determine the differences in survival for out-of-hospital advanced airway intervention (AAI) compared with basic airway intervention (BAI) in cardiac arrest.

BACKGROUND

AAI is commonly utilized in cardiac arrest in the out-of-hospital setting as a means to secure the airway. Observational studies and clinical trials of AAI suggest that AAI is associated with worse outcomes in terms of survival. No controlled trials exist that compares AAI to BAI.

METHODS

We conducted a bias-adjusted meta-analysis on 17 observational studies. The outcomes were survival, short-term (return of spontaneous circulation and to hospital admission), and longer-term (to discharge, to one month survival). We undertook sensitivity analyses by analyzing patients separately: those who were 16 years and older, nontrauma only, and attempted versus successful AAI.

RESULTS

This meta-analysis included 388,878 patients. The short-term survival for AAI compared to BAI were overall OR 0.84(95% CI 0.62 to 1.13), for endotracheal intubation (ETI) OR 0.79 (95% CI 0.54 to 1.16), and for supraglottic airways (SGA) OR 0.59 (95% CI 0.39 to 0.89). Long-term survival for AAI were overall OR 0.49 (95% CI 0.37 to 0.65), for ETI OR 0.48 (95% CI 0.36 to 0.64), and for SGA OR 0.35 (95% CI 0.28 to 0.44). Sensitivity analyses shows that limiting analyses to adults, non-trauma victims, and instances where AAI was both attempted and successful did not alter results meaningfully. A third of all studies did not adjust for any other confounding factors that could impact on survival.

CONCLUSIONS

This meta-analysis shows decreased survival for AAIs used out-of-hospital in cardiac arrest, but are likely biased due to confounding, especially confounding by indication. A properly conducted prospective study or a controlled trial is urgently needed and are possible to do.

Decision-tree model for predicting outcomes after out-of-hospital cardiac arrest in the emergency department

Introduction

Estimation of outcomes in patients after out-of-hospital cardiac arrest (OHCA) soon after arrival at the hospital may help clinicians guide in-hospital strategies, particularly in the emergency department. This study aimed to develop a simple and generally applicable bedside model for predicting outcomes after cardiac arrest.

Methods

We analyzed data for 390,226 adult patients who had undergone OHCA, from a prospectively recorded nationwide Utstein-style Japanese database for 2005 through 2009. The primary end point was survival with favorable neurologic outcome (cerebral performance category (CPC) scale, categories 1 to 2 [CPC 1 to 2]) at 1 month. The secondary end point was survival at 1 month. We developed a decision-tree prediction model by using data from a 4-year period (2005 through 2008, n = 307,896), with validation by using external data from 2009 (n = 82,330).

Results

Recursive partitioning analysis of the development cohort for 10 predictors indicated that the best single predictor for survival and CPC 1 to 2 was shockable initial rhythm. The next predictors for patients with shockable initial rhythm were age (<70 years) followed by witnessed arrest and age (>70 years) followed by arrest witnessed by emergency medical services (EMS) personnel. For patients with unshockable initial rhythm, the next best predictor was witnessed arrest. A simple decision-tree prediction mode permitted stratification into four prediction groups: good, moderately good, poor, and absolutely poor. This model identified patient groups with a range from 1.2% to 30.2% for survival and from 0.3% to 23.2% for CPC 1 to 2 probabilities. Similar results were observed when this model was applied to the validation cohort.

Conclusions

On the basis of a decision-tree prediction model using four prehospital variables (shockable initial rhythm, age, witnessed arrest, and witnessed by EMS personnel), OHCA patients can be readily stratified into the four groups (good, moderately good, poor, and absolutely poor) that help predict both survival at 1 month and survival with favorable neurologic outcome at 1 month. This simple prediction model may provide clinicians with a practical bedside tool for the OHCA patient's stratification in the emergency department.