The PTL, Combitube, laryngeal mask, and oral airway: a randomized prehospital comparative study of ventilatory device effectiveness and cost-effectiveness in 470 cases of cardiorespiratory arrest

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 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.

Use of supraglottic airway devices under capnography monitoring during cardiopulmonary resuscitation: A systematic review

BACKGROUND

Bag-valve-mask ventilation is the most commonly applied method during cardiopulmonary resuscitation. Globally, advanced airway management with blind insertion devices such as supraglottic airway devices has been implemented for years by different emergency services. The efficiency of ventilation via such devices could be measured by capnography.

OBJECTIVE

The objective of this study was to determine whether capnography is useful in patients undergoing cardiopulmonary resuscitation and to assess the effectiveness of ventilation via supraglottic airway devices.

REVIEW METHODS USED

This is a systematic review written following the steps of Preferred Reporting Items for Systematic Review and Meta-analyses protocols.

DATA SOURCES

A bibliographic search was carried out from the following databases: EBSCOhost, Scopus, EMBASE, Virtual Health Library, PubMed, Cochrane Library, Spanish Medical Index, Spanish Bibliographic Index in Health Sciences, and Latin American and Caribbean Health Sciences Literature, from inception until September 2019.

REVIEW METHODS

Studies describing the use of capnography with supraglottic airway devices during cardiopulmonary resuscitation manoeuvres were selected and evaluated using the Critical Appraisal Skills Programme.

RESULTS

Twenty-four articles were identified by title and abstract: six were randomised clinical trials, 11 were nonrandomised clinical trials, six were descriptive prospective studies, and one was a descriptive retrospective study. Nine primary research articles were selected for synthesis. Only one provided objective values of capnography obtained with ventilation with these devices, correlating them with the results of resuscitation.

CONCLUSIONS

The evidence published so far is scarce, mostly from observational studies with high risk of bias in general. Although a degree of recommendation cannot be established, some results indicate that capnography has the potential to facilitate advanced clinical practice of ventilation with supraglottic airway devices during cardiopulmonary resuscitation.

Effectiveness of different supralottic airways during resuscitation manoeuvres. A systematic review

INTRODUCTION

Supraglottic airways, which are easily inserted and minimize interruptions in cardiopulmonary resuscitation manoeuvres, are now widely used in pre- and in-hospital emergencies. However, most studies in these devices do not specify whether they ensure good ventilation during CPR. This systematic review aims to determine whether there is evidence that supraglotic airways enable effective ventilation during resuscitation.

METHODS

The MEDLINE and COCHRANE databases were searched for studies published in English up to 30 November 2018. Eligible studies were all those that objectively evaluated tidal volume during resuscitation maneuvers in patients over 18 years of age using various supraglottic airways.

RESULTS

A total of 3734 articles were identified, of which 252 were duplicates. Only 1 objectively evaluated ventilation during resuscitation maneuvers and presented data relevant to this review. The study included 470 patients, 51 of which underwent spirometry. Only 4.48% of patients survived to hospital discharge; however, the correlation with ventilation effectiveness was not assessed.

CONCLUSION

There is no scientific evidence that supraglottic airways provide effective ventilation during resuscitation maneuvers. Evaluation by spirometry, chest impedance and ultrasound may help to determine the ventilatory efficacy of supraglottic airways during CPR, and clarify whether this factor contributes to the difficulties experienced in reversing cardiorespiratory arrest.

Endotracheal intubation during out-of-hospital cardiac arrest: New insights from recent clinical trials

Airway management is an important intervention during resuscitation of out-of-hospital cardiac arrest (OHCA). Endotracheal intubation is commonly used by emergency medical services paramedics in the advanced airway management of OHCA, but numerous studies question its safety and effectiveness. Furthermore, there is now increasing use of supraglottic airway devices. In this review, we provide an overview of 3 recent randomized clinical trials of advanced airway management (Pragmatic Airway Resuscitation Trial [PART], AIRWAYS-2, and Cardiac Arrest Airway Management [CAAM]) and highlight new information that is available to guide OHCA airway management practices.

2019 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations: Summary From the Basic Life Support; Advanced Life Support; Pediatric Life Support; Neonatal Life Support; Education, Implementation, and Teams; and First Aid Task Forces

The International Liaison Committee on Resuscitation has initiated a continuous review of new, peer-reviewed, published cardiopulmonary resuscitation science. This is the third annual summary of the International Liaison Committee on Resuscitation International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations. It addresses the most recent published resuscitation evidence reviewed by International Liaison Committee on Resuscitation Task Force science experts. This summary addresses the role of cardiac arrest centers and dispatcher-assisted cardiopulmonary resuscitation, the role of extracorporeal cardiopulmonary resuscitation in adults and children, vasopressors in adults, advanced airway interventions in adults and children, targeted temperature management in children after cardiac arrest, initial oxygen concentration during resuscitation of newborns, and interventions for presyncope by first aid providers. Members from 6 International Liaison Committee on Resuscitation task forces have assessed, discussed, and debated the certainty of the evidence on the basis of the Grading of Recommendations, Assessment, Development, and Evaluation criteria, and their statements include consensus treatment recommendations. Insights into the deliberations of the task forces are provided in the Justification and Evidence to Decision Framework Highlights sections. The task forces also listed priority knowledge gaps for further research.

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.

Airway management techniques in a restricted-access situation: a manikin study

BACKGROUND

Access to patients can be restricted in emergency situations. A variety of techniques and devices are available for use in patients who require oxygenation in a restricted-access situation.

OBJECTIVES

The aim of this study was to investigate whether there is one ventilation technique that is superior to others.

MATERIALS AND METHODS

Fifty-four emergency medical services providers including emergency medical technicians, paramedics and physicians were asked to use a bag-valve mask (BVM), a laryngeal mask airway (LMA), and a laryngeal tube (LT) to ventilate a full-scale manikin sitting upright in the driver's seat of a motor vehicle. Access to the manikin was gained through the side window and from the backseat.

RESULTS

There were significant differences in time to first successful ventilation between the two approaches for access to the airway. The fastest median time to ventilation was obtained with the BVM (7 and 8 s), followed by the LT (13 and 14 s) and the LMA (15 s for both types of access). Overall success rates were 97.2% for the BVM, 96.3% for the LMA, and 100% for the LT. Most participants needed two attempts for each device. There were no significant differences between participants depending on the level of qualification or professional experience. The BVM was rated the lowest and the LT was rated the highest for ease of use.

CONCLUSION

Supraglottic airway devices appear to offer advantages in restricted-access situations.

Cardiac Arrest Resuscitation

Cardiac arrest is a dynamic disease that tests the multitasking and leadership abilities of emergency physicians. Providers must simultaneously manage the logistics of resuscitation while searching for the cause of cardiac arrest. The astute clinician will also realize that he or she is orchestrating only one portion of a larger series of events, each of which directly affects patient outcomes. Resuscitation science is rapidly evolving, and emergency providers must be familiar with the latest evidence and controversies surrounding resuscitative techniques. This article reviews evidence, discusses controversies, and offers strategies to provide quality cardiac arrest resuscitation.

Emergency medical services controversies in British Columbia

L’encombrement des salles d’urgence a atteint un niveau de crise et les retombées s’étendent au-delà des murs des hôpitaux. De plus en plus, le personnel des urgences surchargées utilise la tactique du «détournement des ambulances», obligeant les préposés aux SMU à se diriger vers le prochain établissement adéquat. Comme de plus en plus d’hôpitaux ont recours au détournement, les patients s’accumulent dans les établissements qui les acceptent jusqu’à ce que ceux-ci débordent également. Finalement, plus personne n’accepte de patients et les préposés aux SMU doivent attendre avec leurs patients dans les corridors de l’urgence qu’une civière se libère. En raison de cette situation, il y a moins d’ambulances disponibles pour répondre aux appels 911. Le principal mandat d’un service pré-hospitalier est de prodiguer des soins sur les lieux de l’incident et non dans les corridors d’une urgence et il est inacceptable qu’une pénurie de lits à l’urgence entraîne des retards de réponse au 911.

La plupart des gens sont d’accord pour dire qu’il est inacceptable que des patients malades aient à attendre dans les corridors de l’urgence pour des civières inexistantes; cependant, même si cette situation est dangereuse, elle l’est moins que le fait d’obliger ces mêmes patients à attendre indûment à la maison l’arrivée des SMU. Les hôpitaux devraient peut-être prendre un engagement moral d’accepter les patients peu importe la situation d’encombrement, puis d’assigner les ressources nécessaires pour les soigner; ou les services ambulanciers devraient peut-être embaucher et former du personnel pour traiter les patients dans les corridors des urgences. Quelle que soit l’approche adoptée, les hôpitaux et les préposés aux SMU doivent cesser de s’imputer mutuellement la responsabilité du problème et travailler à trouver des solutions.

Feasibility of LMA Supreme for airway management in unconscious patients by ALS paramedics

Background

Airway management to ensure sufficient gas exchange is of major importance in emergency care. The accepted basic technique is to maintain an open airway and perform artificial ventilation in emergency situations is bag-valve mask (BVM) ventilation with manual airway management without airway adjuncts or with an oropharyngeal tube (OPA) only. Endotracheal intubation (ETI) is often referred to as the golden standard of airway management, but is associated with low success rates and significant insertion-related complications when performed by non-anaesthetists. Supraglottic devices (SADs) are one alternative to ETI in these situations, but there is limited evidence regarding the use of SAD in non-cardiac arrest situations. LMA Supreme (LMA-S) is a new SAD which theoretically has an advantage concerning the risk of aspiration due to an oesophageal inlet gastric tube port.

Methods

Forty paramedics were recruited to participate in the study. Adult (>18 years) patients, unconscious due to medical or traumatic cause with a GCS score corresponding to 3–5 and needed airway management were included in the study. Our aim was to study the feasibility of LMA-S as a primary airway method in unconscious patients by advanced life support (ALS) trained paramedics in prehospital care.

Results

Three regional Emergency Medical Service (EMS) services participated and 21 patients were treated during the survey. The LMA-S was placed correctly on the first attempt in all instances 21/21 (100%), with a median time to first ventilation of 9.8 s. Paramedics evaluated the insertion to be easy in every case 21/21 (100%). Because of air leak later in the patient care, the LMA-S was exchanged to an LT-D in two cases and to ETI in three cases (23.81%) by the paramedics. Regurgitation occurred after insertion two times out of 21 (9.52%) and in one of these cases (4.76%), paramedics reported regurgitation inside the LMA-S.

Conclusion

We conclude that the LMA-S seems to be relatively easy and quick to insert in unconscious patients by paramedics. However, we found out that there were ventilation related problems with the LMA-S. Further studies are warranted.

Comparison of endotracheal intubation, combitube, and laryngeal mask airway between inexperienced and experienced emergency medical staff: A manikin study

Background:

Emergency Medical Service (EMS) personnel manage the airway, but only a group of them are allowed to engage in Endotracheal Intubation (ETI). Our purpose was to evaluate if the use of laryngeal mask airway (LMA) or Combitube can be used by inexperienced care providers.

Materials and Methods:

A randomized, prospective manikin study was conducted. Fifty-nine participants were randomly assigned into two groups. Experienced group included 16 paramedics, eight anesthetic-technicians, and inexperienced group included 27 Emergency Medical Technician-Basic (EMT-B) and eight nurses. Our main outcomes were success rate and time to airway after only one attempt.

Results:

Airway success was 73% for ETI, 98.3% for LMA, and 100% for Combitube. LMA and Combitube were faster and had greater success than ETI (P = 0.0001). Inexperienced had no differences in time to securing LMA compared with experienced (6.05 vs. 5.4 seconds, respectively, P = 0.26). One failure in inexperienced, and no failure in experienced group occurred to secure the LMA (P = 0.59). The median time to Combitube placement in experienced and inexperienced was 5.05 vs. 5.00 seconds, P = 0.65, respectively. Inexperienced and experienced groups performed ETI in 19.15 and 17 seconds, respectively (P = 0.001). After the trial, 78% preferred Combitube, 15.3% LMA, and 6.8% ETI as the device of choice in prehospital setting.

Conclusion:

Time to airway was decreased and success rate increased significantly with the use of LMA and combitube compared with ETI, regardless of the experience level. This study suggests that both Combitube and LMA may be acceptable choices for management of airway in the prehospital setting for experienced and especially inexperienced EMS personnel.

Does pre-hospital endotracheal intubation improve survival in adults with non-traumatic out-of-hospital cardiac arrest? A systematic review

INTRODUCTION

Endotracheal intubation (ETI) is currently considered superior to supraglottic airway devices (SGA) for survival and other outcomes among adults with non-traumatic out-of-hospital cardiac arrest (OHCA). We aimed to determine if the research supports this conclusion by conducting a systematic review.

METHODS

We searched the MEDLINE, Scopus and CINAHL databases for studies published between January 1, 1980, and 30 April 30, 2013, which compared pre-hospital use of ETI with SGA for outcomes of return of spontaneous circulation (ROSC); survival to hospital admission; survival to hospital discharge; and favorable neurological or functional status. We selected studies using pre-specified criteria. Included studies were independently screened for quality using the Newcastle-Ottawa scale. We did not pool results because of study variability. Study outcomes were extracted and results presented as summed odds ratios with 95% CI.

RESULTS

We identified five eligible studies: one quasi-randomized controlled trial and four cohort studies, involving 303,348 patients in total. Only three of the five studies reported a higher proportion of ROSC with ETI versus SGA with no difference reported in the remaining two. None found significant differences between ETI and SGA for survival to hospital admission or discharge. One study reported better functional status at discharge for ETI versus SGA. Two studies reported no significant difference for favorable neurological status between ETI and SGA.

CONCLUSION

Current evidence does not conclusively support the superiority of ETI over SGA for multiple outcomes among adults with OHCA.

Chest compressions do not disrupt the seal created by the laryngeal mask airway during positive pressure ventilation: a preliminary porcine study

OBJECTIVE

Pulmonary aspiration of gastric contents occurs 20 to 30% of the time during cardiopulmonary resuscitation (CPR) of cardiac arrest due to loss of protective airway reflexes, pressure changes generated during CPR, and positive pressure ventilation (PPV). Although the American Heart Association has recommended the laryngeal mask airway (LMA) as an acceptable alternative airway for use by emergency medical service personnel, concerns over the capacity of the device to protect from pulmonary aspiration remain. We sought to determine the occurrence of aspiration after LMA placement, CPR, and PPV.

METHODS

We inserted a size 4 LMA, modified so that a vacuum catheter could be advanced past the LMA diaphragm, into the hypopharynx of 16 consecutive postexperimental mixed-breed domestic swine. Fifteen millilitres of heparinized blood was instilled into the oropharynx. Chest compressions were performed for 60 seconds with asynchronous ventilation via a mechanical ventilator. We then suctioned through the LMA for 1 minute. The catheter was removed and inspected for signs of blood. The LMA cuff was deflated, removed, and inspected for signs of blood.

RESULTS

None of 16 animals (95% CI 0-17%) had a positive test for the presence of blood in both the vacuum catheter and the intima of the LMA diaphragm.

CONCLUSIONS

In this swine model of regurgitation after LMA placement, there were no cases with evidence of blood beyond the seal created by the LMA cuff. Future studies are needed to determine the frequency of pulmonary aspiration after LMA placement during CPR and PPV in the clinical setting.

Utility of the Pentax-AWS in performing tracheal intubation while wearing chemical, biological, radiation and nuclear personal protective equipment: a randomised crossover trial using a manikin

INTRODUCTION

Following a chemical, biological, radiation and nuclear (CBRN) incident, prompt establishment of an advanced airway is required for patients with respiratory failure within the warm zone, while wearing personal protective equipment (PPE). Previous studies reported that intubation attempts were prolonged, and incidence of esophageal intubation was increased with conventional Macintosh laryngoscope (McL), while wearing CBRN-PPE. Pentax-AWS (AWS), a recently introduced portable video laryngoscope, was compared with the McL to test its utility for tracheal intubation while wearing CBRN-PPE.

METHODS

31 participants performed unsuited and suited intubations on an advanced life support simulator. The sequence of intubating devices and PPE wearing were randomised. Time to complete tracheal intubation (primary end point), time to see the vocal cords, overall success rate, percentage of glottic opening, dental compression and ease of intubation were measured.

RESULTS

Suited intubations required significantly longer time to complete intubation than unsuited intubations, in both McL and AWS (22.2 vs 26.4 s, 14.2 vs 18.2 s, respectively). However, suited AWS intubations required shorter time to complete tracheal intubation than unsuited McL intubations (18.2 vs 22.2 s). In secondary outcomes, moreover, suited intubations using the AWS compared favourably with unsuited intubations using the McL.

CONCLUSIONS

Although the CBRN-PPE adversely affected time required to complete tracheal intubation with the AWS, suited intubations using the AWS were even superior to unsuited intubations using the McL. The AWS should be a promising device to perform tracheal intubation while wearing the CBRN-PPE.

Intubating laryngeal mask airway placement by non-physician healthcare providers in management out-of-hospital cardiac arrests: a case series

AIM OF THE STUDY

The role of supralaryngeal devices in airway management in out-of-hospital cardiac arrests (OHCA) remains controversial. The aim of this prospective observational trial was to evaluate the feasibility and effectiveness of intubating laryngeal mask airway (ILMA) when used by trained prehospital emergency nurses in the setting of OHCA.

METHODS

After approval from the Research Ethics Board, prehospital emergency nurses trained in placement of ILMA (Fastrach™, LMA Vitaid, Toronto, Ontario, Canada) followed a formal protocol for airway control during OHCA. The primary outcome was the success rate of ILMA placement, while secondary outcomes were success rate of tracheal intubation through the ILMA, and the incidence of regurgitation of gastric contents.

RESULTS

During the study period, 302 ILMA placements were attempted by emergency nurses during OHCA resuscitation. After ILMA placement, but before attempt for intubation, ventilation was possible in 290 patients (96%). Obstruction or major leaks were observed in 12 patients (4%). Tracheal tube insertion through the ILMA was attempted in 265 patients, and was performed in 254 (95.8%). This allowed for proper lung ventilation through the tracheal tube in 242 cases whereas 12 tubes were esophageal or proved obstructed. Regurgitation of gastric contents occurred in 43 (14.2%) patients; in 23 cases before arrival of the first aid team, in 18 cases before ILMA placement, and in 2 cases after the ILMA placement.

CONCLUSION

The use of ILMA for airway management by trained emergency nurses during OHCA resuscitation is feasible and allows for effective airway management. The success rate of tracheal tube placement through the ILMA was high. In addition, the incidence of regurgitation was lower when using the ILMA than that previous historical reports with face-mask ventilation.

Prehospital non-drug assisted intubation for adult trauma patients with a Glasgow Coma Score less than 9

OBJECTIVES

Prehospital airway management for adult trauma patients remains controversial. We sought to review the frequency that paramedic non-drug assisted intubation or attempted intubation is performed for trauma patients in Ontario, Canada, and determine its association with mortality.

METHODS

We conducted a retrospective cohort study using the Ontario Trauma Registry's Comprehensive Data Set for 2002-2009. Eligible patients were greater than 16 years of age, had an initial Glasgow Coma Score of less than 9 and were cared for by ground-based non-critical care paramedics. The primary outcome was mortality. Outcomes were compared between patients undergoing prehospital intubation versus basic airway management. Logistic regression analyses were used to quantify the association between prehospital intubation and mortality.

RESULTS

Of the 2229 patients included in the analysis, 671 (30.1%) underwent prehospital intubation. Annual rates of prehospital intubation declined from 33.7% to 14.0% (ptrend<0.0001) over the study period. Unadjusted death rates were 66.0% versus 34.8% in the intubation and basic airway groups, respectively (p<0.0001). Intubation in the prehospital setting was associated with a heightened risk of mortality (adjusted OR 2.8, 95% CI 1.1 to 7.6).

CONCLUSIONS

Prehospital non-drug assisted intubation for trauma is being performed less frequently in Ontario, Canada. Within our study population, paramedic non-drug assisted intubation or attempted intubation was associated with a heightened risk of mortality.

Evaluation of prehospital insertion of the laryngeal mask airway by primary care paramedics with only classroom mannequin training

INTRODUCTION

The laryngeal mask airway (LMAtrade mark airway) provides adequate ventilation and offers a suitable alternative for airway management in patients with cardiac arrest if primary care paramedics do not have intubation skills or are unable to intubate. Training in the use of the LMA usually occurs in the operating room.

OBJECTIVE

To describe the use of the LMA by paramedics in prehospital adult non-traumatic cardiac arrest patients after classroom mannequin training. The study took place in a suburban rural emergency medical service.

METHODS

This is a 2-phase observational study of the effect of paramedic training for LMA insertion using a mannequin and the success rate in the prehospital setting. All paramedics successfully completed classroom mannequin training. All subsequent prehospital adult non-traumatic cardiac arrest patients from mid-February 1999 to Mar. 31, 2000, were eligible. Subjective assessment of chest expansion, ease of ventilation and auscultation defined adequacy of ventilation. Data collected included the number of insertion attempts, reasons for failure, ease of insertion, adverse events and reasons for not attempting intubation. Statistical analysis comprised descriptive frequencies, chi-squared tests for comparison of categorical variables and analysis of variance for continuous variables.

RESULTS

208 paramedics (100%) successfully completed training. The mean number of attempts was 1, and only 4 (2.1%) paramedics required a second attempt with a mannequin. The paramedics' perception of ease of use comparing the LMA with a bag valve mask (BVM) was evenly distributed across the 3 descriptors: 70 (39%) scored the LMA as easier to use, 57 (31%) as more difficult, and 54 (30%) stated there would be no difference. Of the 291 arrests during the study period, insertion of the LMA was attempted in 283 (97.3%) and was successful in 199 (70%) patients. The LMA became dislodged in 5 (2.5%) cases and was removed in 12 (6%) to clear vomit from the airway. The overall success rate was 182 (64%). The incidence of regurgitation prior to attempted insertion of the LMA was 28% (79 patients). Success rates did not vary significantly with the incidence of vomiting prior to insertion (p = 0.11). The majority of the paramedics evaluated LMA insertion as Very easy 49/220 (22.3%) or Easy 87/220 (39.6%). Paramedic evaluation of ease of use varied with success (p = 0.001).

CONCLUSIONS

This study reports a 100% training success rate with a mannequin and a 64% success with LMA insertion and ventilation in the field by paramedics among adult out-of-hospital non-traumatic cardiac arrest patients.

Success and Complication Rates with Prehospital Placement of an Esophageal-Tracheal Combitube as a Rescue Airway

Introduction:

Previous studies have proven the success of the EsophagealTracheal Combitube (ETC) as a primary airway, but not as a rescue airway.

Objective:

The object of this study was to observe success and complication rates of paramedic placement of an ETC as a rescue airway, and to compare success rates with endotracheal tube (ETT) intubation. The primary outcome indicator was placement with successful ventilation. Complication rates, esophageal placement, and return of spontaneous circulation (ROSC) were secondary measures.

Methods:

A retrospective review of the records of patients who had ETC attempts by Emergency Medical Services (EMS) was conducted for a period of three years. Complications were defined a priori. The ETC is used primarily as rescue airway for a failed attempt at an endotracheal tube (ETT) intubation. A control group for ETT placements was drawn from the EMS quality assurance (QA) database for the same period.

Results:

Esophageal-Tracheal Combitube insertion was attempted on 162 patients, of which, 113 (70%) were successful, 46 (28%) failed, and the outcome of three (2%) was not recorded. Inability to place the ETC occurred in 29 (18%) patients, and accounted for 48% (22/46) of failures. The use of the ETC caused dental trauma in one patient, and one placement of the ETC was related to the onset of subcutaneous emphysema. Blood in the ETC from active upper gatrointestinal bleeding occurred in nine patients (6%), and four tubes (3%) became dislodged en route to the hospital. The a priori complication rate was 44/162 (27%). Inability to determine placement of the ETC due to emesis from both ports occurred in 21 cases. Combining these problems with the a priori complications, the overall rate was 40% (65/162). EsophagealTracheal Combitube location was noted in a subset of 90 charts, of which, 76 (84%) were esophageal, and 14 (16%) were tracheal. Thirteen of 126 (10%) patients in cardiac arrest had return of spontaneous circulation (ROSC) in the field after placement of the ETC. An ETT was attempted in 128 control patients, of which, 107 (84%) were successful, 21 (16%) failed (odds ratio (OR) for ETT vs. ETC = 2.1; 95% CI = 1.12–3.86).

Conclusion:

Despite a low ROSC rate, the complication and success rates of ETC are acceptable for a rescue airway device. Tracheal placement of the Combitube is uncommon, but requires fail-safe discrimination. Similar to previous reports, the success ratio for ETT was greater than for the ETC.

Cardiopulmonary resuscitation and management of cardiac arrest

The best chance of survival with a good neurological outcome after cardiac arrest is afforded by early recognition and high-quality cardiopulmonary resuscitation (CPR), early defibrillation of ventricular fibrillation (VF), and subsequent care in a specialist center. Compression-only CPR should be used by responders who are unable or unwilling to perform mouth-to-mouth ventilations. After the first defibrillator shock, further rhythm checks and defibrillation attempts should be performed after 2 min of CPR. The underlying cause of cardiac arrest can be identified and treated during CPR. Drugs have a limited effect on long-term outcomes after cardiac arrest, although epinephrine improves the success of resuscitation, and amiodarone increases the success of defibrillation for refractory VF. Supraglottic airway devices are an alternative to tracheal intubation, which should be attempted only by skilled rescuers. Care after cardiac arrest includes controlled reoxygenation, therapeutic hypothermia for comatose survivors, percutaneous coronary intervention, circulatory support, and control of blood-glucose levels and seizures. Prognostication in comatose survivors of cardiac arrest needs a careful, multimodal approach using clinical and electrophysiological assessments after at least 72 h.

Update on cardiopulmonary resuscitation guidelines of interest to anesthesiologists

BACKGROUND AND OBJECTIVES

The new cardiopulmonary resuscitation (CPR) guidelines emphasize the importance of high-quality chest compressions and modify some routines. The objective of this report was to review the main changes in resuscitation practiced by anesthesiologists.

CONTENTS

The emphasis on high-quality chest compressions with adequate rate and depth allowing full recoil of the chest and with minimal interruptions is highlighted in this update. One should not take more than ten seconds checking the pulse before starting CPR. The universal relationship of 30:2 is maintained, modifying its order, initiating with chest compressions, followed by airways and breathing (C-A-B instead of A-B-C). The procedure "look, listen, and feel whether the patient is breathing" was removed from the algorithm, and the use of cricoid pressure during ventilations is not recommended any more. The rate of chest compressions was changed for at least one hundred per minute instead of approximately one hundred per minute, and its depth in adults was changed to 5 cm instead of the prior recommendation of 4 to 5 cm. The single shock is maintained, and it should be of 120 to 200 J when it is biphasic; and 360 J when it is monophasic. In advanced cardiac life support, the use of capnography and capnometry to confirm intubation and monitoring the quality of CPR is a formal recommendation. Atropine is no longer recommended for routine use in the treatment of pulseless electrical activity or asystole.

CONCLUSIONS

Updating the phases of the new CPR guidelines is important, and continuous learning is recommended. This will improve the quality of resuscitation and survival of patients in cardiac arrest.

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

BACKGROUND

There is no evidence that the advanced airway ventilation (AAV) method improves patient outcome in the pre-hospital cardiac arrest setting.

OBJECTIVE

The aim of this study was to estimate the effectiveness of AAV vs. bag-mask ventilation (BMV) for cardiopulmonary arrest (CPA) patients, when administered by a licensed emergency medical technician in the pre-hospital setting.

METHODS

The study used the database of patients who suffered out-of-hospital cardiogenic CPA from 2006 to 2007 in our hospital. Patient records were searched for the method of pre-hospital airway management (BMV or AAV) and the patient's outcomes were compared between groups. The primary endpoint was a favorable neurological outcome; the secondary endpoints were rate of return of spontaneous circulation (ROSC) and rate of admission to the intensive care unit (ICU).

RESULTS

A total of 355 CPA patients (156 BMV and 199 AAV) were retrospectively enrolled. There was no significant difference in demographics between the two groups. The transportation time exceeded 30 min in both groups. The overall ROSC rate and ICU admission rate were significantly higher in the AAV group (p = 0.0352 and p = 0.0089, respectively). The data showed that AAV (odds ratio 1.960; 95% confidence interval 1.015-3.785) resulted in a higher overall ROSC rate than BMV, but there were no significant differences in either the rate of pre-hospital ROSC or in favorable neurological outcome.

CONCLUSION

AAV may yield advantages over BMV in the overall rate of ROSC in CPA patients, but both approaches for airway management in this study resulted in a comparably favorable neurological outcome. Earlier ROSC would be required for improved overall outcome.

Equipment to manage a difficult airway during anaesthesia

Airway complications are a leading cause of morbidity and mortality in anaesthesia. Effective management of a difficult airway requires the timely availability of suitable airway equipment. The Australian and New Zealand College of Anaesthetists has recently developed guidelines for the minimum set of equipment needed for the effective management of an unexpected difficult airway (TG4 [2010] www.anzca.edu.au/resources/professionaldocuments). TG4 [2010] is based on expert consensus, underpinned by wide consultation and an extensive review of the available evidence, which is summarised in a Background Paper (TG4 BP [2010] www.anzca.edu.au/ resources/professional-documents). TG4 [2010] will be reviewed at the end of one year and thereafter every five years or more frequently if necessary. The current paper is reproduced directly from the Background Paper (TG4 BP [2010]).

A meta-analysis of prehospital airway control techniques part II: alternative airway devices and cricothyrotomy success rates

BACKGROUND

Airway management is a key component of prehospital care for seriously ill and injured patients. Oral endotracheal intubation (OETI) is the definitive airway of choice in most emergency medical services (EMS) systems. However, OETI may not be an approved skill for some clinicians or may prove problematic in certain patients because of anatomic abnormalities, trauma, or inadequate relaxation. In these situations alternative airways are frequently employed. However, the reported success rates for these devices vary widely, and established benchmarks are lacking.

OBJECTIVE

We sought to determine pooled estimates of the success rates of alternative airway devices (AADs) and needle cricothyrotomy (NCRIC) and surgical cricothyrotomy (SCRIC) placement through a meta-analysis of the literature.

METHODS

We performed a systematic literature search for all English-language articles reporting success rates for AADs, SCRIC, and NCRIC. Studies of field procedures performed by prehospital personnel from any nation were included. All titles were reviewed independently by two authors using prespecified inclusion criteria. Pooled estimates of success rates for each airway technique were calculated using a random-effects meta-analysis model.

RESULTS

Of 2,005 prehospital airway titles identified, 35 unique studies were retained for analysis of AAD success rates, encompassing a total of 10,172 prehospital patients. The success rates for SCRIC and NCRIC were analyzed across an additional 21 studies totaling 512 patients. The pooled estimates (and 95% confidence intervals [CIs]) for intervention success across all clinicians and patients were as follows: esophageal obturator airway-esophageal gastric tube airway (EOA-EGTA) 92.6% (90.1%-94.5%); pharyngeotracheal lumen airway (PTLA) 82.1% (74.0%-88.0%); esophageal-tracheal Combitube (ETC) 85.4% (77.3%-91.0%); laryngeal mask airway (LMA) 87.4% (79.0%-92.8%); King Laryngeal Tube airway (King LT) 96.5% (71.2%-99.7%); NCRIC 65.8% (42.3%-83.59%); and SCRIC 90.5% (84.8%-94.2%).

CONCLUSIONS

We provide pooled estimates for prehospital AAD, NCRIC, and SCRIC airway interventions. Of the AADs, the King LT demonstrated the highest insertion success rate (96.5%), although this estimate is based on limited data, and data regarding its ventilatory effectiveness are lacking; more data are available for the ETC and LMA. The ETC, LMA, and PTLA all had similar-but lower-success rates (82.1%-87.4%). NCRIC has a low rate of success (65.8%); SCRIC has a much higher success rate (90.5%) and should be considered the preferred percutaneous rescue airway.

Part 8: adult advanced cardiovascular life support: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care

The goal of therapy for bradycardia or tachycardia is to rapidly identify and treat patients who are hemodynamically unstable or symptomatic due to the arrhythmia. Drugs or, when appropriate, pacing may be used to control unstable or symptomatic bradycardia. Cardioversion or drugs or both may be used to control unstable or symptomatic tachycardia. ACLS providers should closely monitor stable patients pending expert consultation and should be prepared to aggressively treat those with evidence of decompensation.

The high-risk airway

There are few conditions in emergency medicine as potentially challenging and high-risk as the difficult or failed airway. The emergency physician must be able to anticipate the difficult or failed airway, recognize associated physiologic deficits, and plan accordingly. Preparation, pretreatment strategies, and selection of alternative airway devices may mitigate the potential morbidity and management failure associated with the high-risk airway. There are a myriad of airway devices new to emergency medicine, which can increase the chance of successful airway management and rescue. Understanding why the airway is potentially difficult and assessing whether oxygenation can be maintained can guide the clinician's strategy and technique for successful management of the high-risk airway.

A STANDING-ORDERPROTOCOL FORCRICOTHYROTOMY INPREHOSPITALEMERGENCYPATIENTS

OBJECTIVE

To study utilization, indications, and outcomes associated with the use of a statewide, emergency medical services (EMS) standing-order protocol for cricothyrotomy.

METHODS

A statewide EMS database was queried for patients who received cricothyrotomy under a standardized, standing-order protocol. Patient EMS and hospital records were reviewed in a defined sequence with information recorded on a standardized collection form.

RESULTS

EMS records included eight years of practice with 1.5 million patient encounters. For each year studied, approximately 540 emergency medical technicians (EMTs) were certified to perform cricothyrotomy. State EMS providers performed a collective mean of eight cricothyrotomy procedures per year (range, 1-17), for a total of 68 cricothyrotomies performed within the eight-year period. Hospital records were available for review in 61 patients. Fifty-six patients received cricothyrotomy by open surgical incision, six by needle with jet ventilation, and one by both methods. Categorization of cricothyrotomy patients as trauma or medical was 61% trauma and 39% medical. Thirty-six patients (59%) were in cardiac arrest on EMS arrival and 12 patients (20%) died during transport. Thirteen trauma patients (21%) were admitted with eight patients surviving to discharge (13%). The neurologic impairment at time of hospital discharge was severe in four, moderate in two, and minimal or none in two patients (3%).

CONCLUSION

A considerable percentage of cricothyrotomy procedures were performed on patients with non-trauma-related diagnoses in this investigation describing a standing-order EMS protocol for cricothyrotomy. The majority of patients undergoing cricothyrotomy with this protocol were in cardiac arrest at the time of cricothyrotomy, with a small minority of patients surviving to hospital discharge and fewer surviving neurologically intact.

ENDOTRACHEALINTUBATION ANDESOPHAGEALTRACHEALCOMBITUBEINSERTION BYREGULARAMBULANCEATTENDANTS: A COMPARATIVETRIAL

OBJECTIVE

Recent cardiac arrest resuscitation guidelines have recommended the esophageal tracheal Combitube (ETC) as an advanced airway management alternative for individuals who infrequently perform endotracheal intubation (ETI). This study attempted to analyze basic (nonparamedic) ambulance attendant success rates at ETI and ETC insertion as well as their continuing skill competency over time and whether ongoing practice on mannequins improved skill performance.

METHODS

Three hundred fifty-seven adult patients in cardiorespiratory arrest were treated by 81 basic ambulance attendants. Original study design called for the analysis of two treatment options in three patient groups: ETC insertion, ETI insertion with mannequin practice (ETI-MP), and ETI insertion without mannequin practice (ETI-NMP). The main outcome measures were:successful insertion and ventilation with ETC or ETI, assessed by receiving physicians; and differences in successful insertion/ventilation between the MP and NMP groups.

RESULTS

Successful insertion (intent-to-treat) for the ETI-NMP group was 70 of 111 (63%; 95% confidence interval [CI], 54-73%); ETI-MP success was 105 of 139 (76%; 95% CI, 67-84%); ETC-NMP success was 26 of 42 (62%; 95% CI, 49-75%); and ETC-MP success was 36 of 53 (68%; 95% CI, 54-82%). Continuing mannequin practice appeared to improve ETI success (as-treated): MP 75% versus NMP 61% (odds ratio, 2.1; 95% CI, 1.11-3.94).

CONCLUSIONS

There were similar rates of successful insertion/ventilation with the ETC and ETI. ETI insertion success was lower without mannequin practice. ETI skill erosion was partially mitigated by additional field experience.