Alternative ventilation strategies in cardiopulmonary resuscitation

Supraglottic Airways Compared With Face Masks for Neonatal Resuscitation: A Systematic Review

BACKGROUND AND OBJECTIVES

Positive pressure ventilation (PPV) is the most important component of neonatal resuscitation, but face mask ventilation can be difficult. Compare supraglottic airway devices (SA) with face masks for term and late preterm infants receiving PPV immediately after birth.

METHODS

Data sources include Medline, Embase, Cochrane Databases, Database of Abstracts of Reviews of Effects, and Cumulative Index to Nursing and Allied Health Literature. Study selections include randomized, quasi-randomized, interrupted time series, controlled before-after, and cohort studies with English abstracts. Two authors independently extracted data and assessed risk of bias and certainty of evidence. The primary outcome was failure to improve with positive pressure ventilation. When appropriate, data were pooled using fixed effect models.

RESULTS

Meta-analysis of 6 randomized controlled trials (1823 newborn infants) showed that use of an SA decreased the probability of failure to improve with PPV (relative risk 0.24; 95% confidence interval 0.17 to 0.36; P <.001, moderate certainty) and endotracheal intubation (4 randomized controlled trials, 1689 newborn infants) in the delivery room (relative risk 0.34, 95% confidence interval 0.20 to 0.56; P <.001, low certainty). The duration of PPV and time until heart rate >100 beats per minute was shorter with the SA. There was no difference in the use of chest compressions or epinephrine during resuscitation. Certainty of evidence was low or very low for most outcomes.

CONCLUSIONS

Among late preterm and term infants who require resuscitation after birth, ventilation may be more effective if delivered by SA rather than face mask and may reduce the need for endotracheal intubation.

Influence of Cardiopulmonary Resuscitation Coaching on Interruptions in Chest Compressions During Simulated Pediatric Cardiac Arrest

OBJECTIVES

To determine the impact of a cardiopulmonary resuscitation coach on the frequency and duration of pauses during simulated pediatric cardiac arrest.

DESIGN

This is a secondary analysis of video data collected from a prospective multicenter trial. Forty simulated pediatric cardiac arrest scenarios (20 noncoach and 20 coach teams), each lasting 18 minutes in duration, were reviewed by three clinical experts to document events surrounding each pause in chest compressions.

SETTING

Four pediatric academic medical centers from Canada and the United States.

SUBJECTS

Two-hundred healthcare providers in five-member interprofessional resuscitation teams that included either a cardiopulmonary resuscitation coach or a noncoach clinical provider.

INTERVENTIONS

Teams were randomized to include either a trained cardiopulmonary resuscitation coach or an additional noncoach clinical provider.

MEASUREMENTS AND MAIN RESULTS

The frequency, duration, and associated factors with each interruption in chest compressions were recorded and compared between the groups with and without a cardiopulmonary resuscitation coach, using t tests, Wilcoxon rank-sum tests, or chi-squared tests, depending on the distribution and types of outcome variables. Mixed-effect linear models were used to explore the effect of cardiopulmonary resuscitation coaching on pause durations, accounting for multiple measures of pause duration within teams. A total of 655 pauses were identified (noncoach n = 304 and coach n = 351). Cardiopulmonary resuscitation-coached teams had decreased total mean pause duration (98.6 vs 120.85 s, p = 0.04), decreased intubation pause duration (median 4.0 vs 15.5 s, p = 0.002), and similar mean frequency of pauses (17.6 vs 15.2, p = 0.33) when compared with noncoach teams. Teams with cardiopulmonary resuscitation coaches are more likely to verbalize the need for pause (86.5% vs 73.7%, p < 0.001) and coordinate change of the compressors, rhythm check, and pulse check (31.7% vs 23.2%, p = 0.05). Teams with cardiopulmonary resuscitation coach have a shorter pause duration than non-coach teams, adjusting for number and types of tasks performed during the pause.

CONCLUSIONS

When compared with teams without a cardiopulmonary resuscitation coach, the inclusion of a trained cardiopulmonary resuscitation coach leads to improved verbalization before pauses, decreased pause duration, shorter pauses during intubation, and better coordination of key tasks during chest compression pauses.

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.

Design and implementation of the Resuscitation Outcomes Consortium Pragmatic Airway Resuscitation Trial (PART)

Airway management is an important component of resuscitation from out-of-hospital cardiac arrest (OHCA). The optimal approach to advanced airway management is unknown. The Pragmatic Airway Resuscitation Trial (PART) will compare the effectiveness of endotracheal intubation (ETI) and Laryngeal Tube (LT) insertion upon 72-h survival in adult OHCA. Encompassing United States Emergency Medical Services agencies affiliated with the Resuscitation Outcomes Consortium (ROC), PART will use a cluster-crossover randomized design. Participating subjects will include adult, non-traumatic OHCA requiring bag-valve-mask ventilation. Trial interventions will include (1) initial airway management with ETI and (2) initial airway management with LT. The primary and secondary trial outcomes are 72-h survival and return of spontaneous circulation. Additional clinical outcomes will include airway management process and adverse events. The trial will enroll a total of 3000 subjects. Results of PART may guide the selection of advanced airway management strategies in OHCA.

Postcardiac Arrest Management

Cardiac arrest afflicts more than 300,000 persons annually in North America alone. Advances in systematic, regimented postresuscitation care have lowered mortality and improved neurologic outcomes in select cohorts of patients over the last decade. Postcardiac arrest care now comprises its own link in the chain of survival. For most patients, high-quality postcardiac arrest care begins in the Emergency Department. This article reviews the evidence and offers treatment strategies for the key components of postcardiac arrest care.

Performance of supraglottic airway devices and 12 month skill retention: a randomized controlled study with manikins

PURPOSE

Airway management for successful ventilation by laypersons and inexperienced healthcare providers is difficult to achieve. Bag-valve mask (BVM) ventilation requires extensive training and is performed poorly. Supraglottic airway devices (SADs) have been successfully introduced to clinical resuscitation practice as an alternative. We evaluated recently introduced (i-gel™ and LMA-Supreme™) and established SADs (LMA-Unique™, LMA-ProSeal™) and BVM used by laypeople in training sessions on manikins.

METHODS

In this randomized controlled study, 267 third-year medical students participated with informed consent and IRB approval. After brief standardized training, each participant applied all devices in a randomized order. Success of device application and ventilation was recorded. Without further training, skill retention was assessed in the same manner 12 months later. Outcome parameters were the number of application attempts, application time, tidal volume and gastric inflation rate recorded at successful attempts, and subjective ease-of-use rating by the participants.

RESULTS

i-gel™ and LMA-Supreme™ were the most successful in the first attempt at both assessments and in the subjective ease-of-use rating. The shortest application time was found with BVM (8 ± 5s in 2008 vs. 9 ± 5s in 2009) and i-gel (10 ± 3s vs. 12 ± 5s). Tidal volumes were disappointing with no device reaching 50% volume within the recommended range (0.4-0.6L). Gastric inflation rate was highest with BVM (18% vs. 20%) but significantly lower with all SADs (0.4-6%; p < 0.001 for 2008 and 2009).

CONCLUSION

SADs showed clear advantages over BVM. Compared with LMA-Unique™ and LMA-ProSeal™, i-gel™ and LMA-Supreme™ led to higher first-attempt success rates and a shorter application time.

Cognitive Control andPrehospital Endotracheal Intubation

Prehospital endotracheal intubation (ETI) is a commonly performed but complex procedure. Cognitive psychology is a science describing how humans organize and process thoughts, including those used in complex operations. We use Rasmussen's Skills-Rules-Knowledge (SRK) framework to highlight the cognitive complexities of prehospital ETI. These findings have important implications for prehospital education and care.

Comparison of ventilation and cardiac compressions using the Impact Model 730 automatic transport ventilator compared to a conventional bag valve with a facemask in a model of adult cardiopulmonary arrest

PURPOSE

To determine the performance of two person CPR on an instrumented manikin by registered nurses using conventional bag valve mask (BVM) ventilation or the Impact Model 730 automatic transport ventilator (Impact 730, Impact Instrumentation, Inc., West Caldwell, NJ) in CPR mode using a face mask.

DESIGN

Randomized crossover quasi-experimental.

SETTING

Laboratory simulation.

SUBJECTS

Twenty-eight registered nurses trained in performing adult cardiopulmonary resuscitation (CPR).

INTERVENTIONS

Basic Life Support was provided by subjects using a conventional bag valve mask (BVM) ventilation or mask ventilation with an automatic transport ventilator, the Impact 730, which incorporates a metronome to facilitate chest compression timing. Subjects alternated performing 4min of CPR using the BVM or Impact 730 to deliver breaths with a mask while the other subject performed compressions.

MEASUREMENTS AND MAIN RESULTS

Flow, volume and pressure were measured using a pneumotachograph and pressure transducer, and ease of use was measured using a 10cm visual analogue scale. There was no statistical or clinical difference between the actual and recommended tidal lung volume (mean+/-S.D.) delivered by the Impact 730 (-120.4+/-91.5ml) versus the BVM (-119.8+/-187.3+/-ml). Ventilation with the BVM resulted in more (137.7+/-143.9ml) air per breath passing through the simulated lower esophageal sphincter compared to the Impact 730 (14.0+/-16.8ml, p<0.05). The reduced mask leak per breath with the Impact 730 (176.1+/-98.3ml) compared to the BVM (367.6+/-337.7ml, p<0.05) is likely to have resulted from the subject being able to manage the mask with two rather than one hand and is reflected in the higher ease of use score on a 10cm visual analogue scale with the Impact 730 (8.06+/-1.35cm) versus the BVM (6.46+/-2.46cm, p<0.05). Subjects tended to deliver slightly more compressions and breaths when using the BVM.

CONCLUSION

Compared to the BVM, the Impact 730 is as effective, easier to use and limits the amount of gas entering the stomach when used during adult CPR in a simulated setting.

Paramedic perceptions of challenges in out-of-hospital endotracheal intubation

OBJECTIVE

Paramedics often perform endotracheal intubation (ETI), insertion of a breathing tube, on critically ill out-of-hospital patients. Recent studies highlight important paramedic ETI shortcomings including adverse events, errors, and poor outcomes resulting from this procedure. Little is known about workforce perceptions of these events. We sought to identify paramedic and physician perceptions regarding the challenges and pitfalls of out-of-hospital ETI.

METHODS

We conducted a qualitative study involving paramedic focus groups sessions and individual interviews with Emergency Medical Services (EMS) physician medical directors. We recorded and transcribed all sessions. We used inductive theory construction to examine, organize, and classify thematic patterns.

RESULTS

Fourteen paramedics and 6 physicians participated. Although paramedics and physicians recognized problems with paramedic ETI, all participants strongly felt that paramedics should continue to perform the procedure. Physicians and paramedics disagreed about the ability of paramedics to perform neuromuscular blockade-assisted intubation. Both groups identified aspects of paramedic education, skills acquisition, and maintenance as core issues. Participants also identified broader factors about the structure of emergency services, the role of the medical director, and workforce culture and professionalism.

CONCLUSION

Paramedics and EMS physicians attribute paramedic ETI performance to a myriad of factors involving EMS education, organization, oversight, retention, and professionalism. Efforts to improve ETI must include strategies to address multiple aspects of EMS operations and culture.

Comparison of ventilation and chest compression performance by bystanders using the Impact Model 730 ventilator and a conventional bag valve with mask in a model of adult cardiopulmonary arrest

"Bystanders" or lay persons are typically the first caregivers to attend to a victim of out-of-hospital cardiopulmonary arrest. Astronaut crew medical officers (CMO) play a similar role to bystanders aboard the International Space Station (ISS). Studies have demonstrated the importance of bystander cardiopulmonary resuscitation (BCPR) for patient survival before the arrival of emergency medical care. Recent apprehension from bystanders about the threat of contracting communicable diseases during BCPR, however, has led to the consideration of other ventilation systems such as the bag-valve mask (BVM) and automatic transport ventilators (ATV). BVM use is called for during CPR aboard the ISS. This study evaluated the ventilation and compression performance of 40 basic CPR-trained bystanders using either a BVM (adult-sized self-inflating bag with face mask) or an ATV (Model 730 ventilator (M730), Impact Instrumentation, Inc., West Caldwell, NJ). Each two-bystander team gave BCPR to a simulated cardiopulmonary arrest victim using the 2-breath/15-compression cycle for 4 min and then switched roles for another 4-min interval. Compared to BVM use, the M730 led to significantly (p<0.05) lower number of breaths, smaller tidal volumes, airway flows, airway pressures, volume of gas entering the stomach per breath and chest compressions for the 4-min period. The M730 also enabled a bystander to meet the recommendation of 4-breath and compression cycles per minute as per Guidelines 2000. Lastly, ease-of-use scores were significantly higher for the M730 compared to the BVM. Overall, the data suggest that the M730 improves the quality of performance for a bystander performing BCPR.

Does the type of out-of-hospital airway interfere with other cardiopulmonary resuscitation tasks?

BACKGROUND

Out-of-hospital rescuers often perform tracheal intubation (TI) prior to other cardiopulmonary resuscitation (CPR) interventions. TI is a complex and error-prone procedure that may interfere with other key resuscitation tasks. We compared the effects of TI versus esophageal tracheal combitube (ETC) insertion on the accomplishment of other interventions during simulated cardiopulmonary resuscitation.

METHODS

In this prospective trial using a human simulator, two-paramedic teams simulated resuscitation of a ventricular fibrillation cardiopulmonary arrest using standard Advanced Cardiac Life Support guidelines. In each of two trials, teams used either TI or ETC as the primary airway device. Following delivery of three rescue shocks, we measured time intervals to successful airway placement, intravenous (IV) line insertion, drug administration, delivery of fourth rescue shock and completion of all four tasks. We also measured the total time without chest compressions. We compared task completion times using non-parametric statistics (Wilcoxon signed-ranks test) with a Bonferroni-adjusted p-value of 0.008.

RESULTS

Twenty teams each completed two scenarios. Participants required a median of 172.5 s (IQR: 146.5-225.5) to accomplish all four tasks. Elapsed time to airway placement was significantly less for ETC than TI (median difference 26.5 s (IQR 13-44.5), p=0.002). Time without chest compressions was less for ETC than TI (median difference 8.5 s (IQR 2.5-23.5), p=0.005). There were no differences between ETC and TI in times to IV placement (median difference 23.5 s (IQR -20 to 61), p=0.11), drug delivery (39.5 s (IQR -18 to 63), p=0.07), delivery of fourth rescue shock (39.5 s (IQR -21.5 to 87.5), p=0.07) or completion of all four tasks (33 s (IQR -11 to 74.5), p=0.08).

CONCLUSION

Compared with TI, ETC reduced time to airway placement and time without chest compressions, but did not affect elapsed times to accomplish other interventions. Additional time differences may be realized if translated to clinical out-of-hospital conditions.

Procedural experience with out-of-hospital endotracheal intubation

OBJECTIVE

Out-of-hospital rescuers likely need regular clinical experience to perform endotracheal intubation (ETI) in a safe and effective manner. We sought to determine the frequency of ETI performed by individual out-of-hospital rescuers.

DESIGN

Analysis of an administrative database of all emergency medical services (EMS) patient care reports in Pennsylvania.

SETTING

Commonwealth of Pennsylvania from January 1 to December 31, 2003.

SUBJECTS

EMS advanced life support rescuers (paramedics, prehospital nurses, and EMS physicians) who reported at least one patient contact during the study period.

INTERVENTIONS

None.

MEASUREMENTS

We calculated individual rescuer ETI frequency and opportunity. We evaluated relationships between ETI frequency and the number of patient contacts. We also examined the relationship with practice setting (air medical vs. ground rescuers and urban vs. rural rescuers).

MAIN RESULTS

In 1,544,791 patient care reports, 11,484 ETIs were reported by 5,245 out-of-hospital rescuers. The median ETI frequency was one (interquartile range, 0-3; range, 0-23). Of 5,245 rescuers, >67% (3,551) performed two or fewer ETIs, and >39% (2,054) rescuers did not perform any ETIs. The median number of ETI opportunities was three (interquartile range, 0-6; range, 0-76). ETI frequency was associated with patient volume (Spearman's rho = 0.67) and was higher for air medical (p = .006) and urban (p < .0001) rescuers. ETI frequency was not associated with response (Spearman's rho = -0.01) or transport (Spearman's rho = -0.06) times.

CONCLUSIONS

Out-of-hospital ETI, an important and difficult resuscitation intervention, is an uncommon event for most rescuers.

Should there be a change in the teaching of airway management in the medical school curriculum?

OBJECTIVE

To evaluate the use of the Laryngeal Mask Airway (LMA), the oesophageal-tracheal combitube (ETC) and the tracheal tube (TT) by medical students, with a view to recommend changes to the medical school curriculum.

METHODS

A prospective cohort study of 93 third-year medical students were taught the use of LMA, ETC and TT on manikins and had their skills tested at 0 and 6 months.

RESULTS

Overall, LMA insertion was the fastest technique with a mean time taken for successful insertion of 32.2 s, compared to that for ETC (55.0 s, P = 0.000) and TT (71.5s, P = 0.000). There was a significant delay in the time taken for insertion at 6 months for all three devices: 13.5 s for the LMA (P = 0.000), 29.6 s for the ETC (P = 0.000) and 31.8 s for the TT (P = 0.001). Both the ETC and the TT had a significantly lower first-attempt success rate at 6 months (ETC: 91% versus 63%, P = 0.000 and TT: 80% versus 55%, P = 0.003) but not the LMA (96% versus 92%, P = 0.549). At 6 months, the overall success rate was 99% for the LMA, 100% for the ETC and 93% for the TT. Complication rate was higher for the ETC (9% versus 46%, P = 0.000) and the TT (38% versus 78%, P = 0.005) but not for the LMA (3% versus 10%, P = 0.688).

CONCLUSIONS

The use of the TT is difficult and the skills acquired by the medical students deteriorate significantly over time. The LMA and the ETC seem to have an advantage over the TT in that they are more easily learnt and the skills better retained. It is recommended that these alternative devices be included in the medical school curriculum for airway management.

Reducing ventilation frequency combined with an inspiratory impedance device improves CPR efficiency in swine model of cardiac arrest

BACKGROUND

The basic premise that frequent ventilations during cardiopulmonary resuscitation (CPR) are a necessity for tissue oxygenation has recently been challenged. An inspiratory impedance threshold device (ITD) recently has also been shown to increase CPR efficiency, principally by augmenting circulation with little impact on ventilation. The optimal compression to ventilation (C/V) is not known for this new device. The purpose of this study was to compare the currently recommended C/V ratio of 5:1 with a 10:1 ratio, +/- the ITD, to optimize circulation and oxygenation during CPR.

METHODS

Thirty-two adult pigs weighing 26-31 kg were randomized to CPR with varying C/V ratios +/- the ITD as follows: A = 5:1, B = 5:1+ITD, C = 10:1, D = 10:1+ITD. After 6 min of untreated ventricular fibrillation (VF), closed-chest standard CPR was performed with an automatic piston device that does not impede passive chest wall recoil, at a continuous compression rate of 100 min(-1). Synchronous breaths were given every 5 or 10 compressions during the decompression phase depending on the group. CPR was performed for 6 min and physiological variables were measured throughout the experimental protocol.

RESULTS

A reduction in the frequency of ventilation from 5:1 to 10:1 resulted in significantly improved arterial and coronary perfusion pressure in a pig model of cardiac arrest. Addition of an ITD resulted in further increases in arterial and coronary perfusion pressures with both 5:1 and 10:1 C/V ratios, without compromising oxygenation.

CONCLUSION

CPR efficiency can be optimized by changing the compression: ventilation ratio from 5:1 to 10:1 and with concurrent use of the inspiratory threshold device.