Effectiveness of various airway management techniques in a bench model simulating a cardiac arrest patient

Efficacy of Laryngeal Tube versus Bag Mask Ventilation by Inexperienced Providers

INTRODUCTION

Bag mask ventilation (BMV) and extraglottic devices (EGDs) are two common methods of providing rescue ventilation. BMV can be difficult to perform effectively, especially for inexperienced providers and in patients with difficult airway characteristics. There is some evidence that the laryngeal tube (LT) can be successfully placed by inexperienced providers to provide effective ventilation. However, it is unclear whether ventilation provided by LT is superior to that of BMV, especially in the hands of inexperienced airway providers. Therefore, we aimed to compare ventilation efficacy of inexperienced airway providers with BMV versus LT by primarily measuring tidal volumes and secondarily measuring peak pressures on a simulated model.

METHODS

We performed a crossover study first year emergency medicine residents and third and fourth year medical students. After a brief instructional video followed by hands on practice, participants performed both techniques in random order on a simulated model for two minutes each. Returned tidal volumes and peak pressures were measured.

RESULTS

Twenty participants were enrolled and 1200 breaths were measured, 600 per technique. The median ventilation volumes were 194 milliliters (mL) for BMV, and 387 mL for the laryngeal tube, with a median absolute difference of 170 mL (95% confidence interval [CI] 157-182 mL) (mean difference 148 mL [95% CI, 138-158 mL], p<0.001). The median ventilation peak pressures were 23 centimeters of water (cm H₂O) for BMV, and 30 cm H₂O for the laryngeal tube, with a median absolute difference of 7 cm H₂O (95% CI, 6-8 cm H2O) (mean difference 8 cm H₂O [95% CI, 7-9 cm H₂O], p<0.001).

CONCLUSION

Inexperienced airway providers were able to provide higher ventilation volumes and peak pressures with the LT when compared to BMV in a manikin model. Inexperienced providers should consider using an LT when providing rescue ventilations in obtunded or hypoventilating patients without intact airway reflexes. Further study is required to understand whether these findings are generalizable to live patients.

Manual ventilation quality is improved with a real-time visual feedback system during simulated resuscitation

INTRODUCTION

Manual ventilations during cardiac arrest are frequently performed outside of recommended guidelines. Real-time feedback has been shown to improve chest compression quality, but the use of feedback to guide ventilation volume and rate has not been studied. The purpose of this study was to determine whether the use of a real-time visual feedback system for ventilation volume and rate improves manual ventilation quality during simulated cardiac arrest.

METHODS

Teams of 2 emergency medical technicians (EMTs) performed two 8-min rounds of cardiopulmonary resuscitation (CPR) on a manikin during a simulated cardiac arrest scenario with one EMT performing ventilations while the other performed compressions. The EMTs switched roles every 2 min. During the first round of CPR, ventilation and chest compression feedback was disabled on a monitor/defibrillator. Following a 20-min rest period and a brief session to familiarize the EMTs with the feedback technology, the trial was repeated with feedback enabled. The primary outcome variables for the study were ventilations and chest compressions within target. Ventilation rate (target, 8-10 breaths/minute) and tidal volume (target, 425-575 ml) were measured using a novel differential pressure-based flow sensor. Data were analyzed using paired t tests.

RESULTS

Ten teams of 2 EMTs completed the study. Mean percentages of ventilations performed in target for rate (41% vs. 71%, p < 0.01), for volume (31% vs. 79%, p < 0.01), and for rate and volume together (10% vs. 63%, p < 0.01) were significantly greater with feedback.

CONCLUSION

The use of a novel visual feedback system for ventilation quality increased the percentage of ventilations in target for rate and volume during simulated CPR. Real-time feedback to perform ventilations within recommended guidelines during cardiac arrest should be further investigated in human resuscitation.

Comparing the neurologic outcomes of patients with out-of-hospital cardiac arrest according to prehospital advanced airway management method and transport time interval

OBJECTIVE

The incidences of prehospital advanced airway management by emergency medical technicians in South Korea are increasing; however, whether this procedure improves the survival outcomes of patients experiencing out-of-hospital cardiac arrest remains unclear. The present study aimed to investigate the association between prehospital advanced airway management and neurologic outcomes according to a transport time interval (TTI) using the Korean Cardiac Arrest Research Consortium database.

METHODS

We retrospectively analyzed the favorable database entries that were prospectively collected between October 2015 and December 2016. Patients aged 18 years or older who experienced cardiac arrest that was presumed to be of a medical etiology and that occurred prior to the arrival of emergency medical service personnel were included. The exposure variable was the type of prehospital airway management provided by emergency medical technicians. The primary endpoint was a favorable neurologic outcome.

RESULTS

Of 1,871 patients who experienced out-of-hospital cardiac arrest, 785 (42.0%), 121 (6.5%), and 965 (51.6%) were managed with bag-valve-mask ventilation, endotracheal intubation (ETI), and supraglottic airway (SGA) devices, respectively. SGAs and ETI provided no advantage in terms of favorable neurologic outcome in patients with TTIs ≥12 minutes (odds ratio [OR], 1.37; confidence interval [CI], 0.65-2.87 for SGAs; OR, 1.31; CI, 0.30-5.81 for ETI) or in patients with TTI <12 minutes (OR, 0.57; CI, 0.31-1.07 for SGAs; OR, 0.63; CI, 0.12-3.26 for ETI).

CONCLUSION

Neither the prehospital use of SGA nor administration of ETI was associated with superior neurologic outcomes compared with bag-valve-mask ventilation.

An analysis of the relationship between the applied medical rescue actions and the return of spontaneous circulation in adults with out-of-hospital sudden cardiac arrest

Sudden cardiac arrest (SCA) is a significant medical and social issue, the main cause of death in Europe and the United States.The aim of the research was to evaluate the effectiveness of emergency medical procedures applied by emergency medical teams in prehospital care in the context of return of spontaneous circulation (ROSC).The case-control study was based on the medical documentation of the Rescue Service in Katowice (responsible for monitoring 2.7 million inhabitants of the region) referring to 2016. The research involved exclusively adults (ie, individuals older than 18 years) with out-of-hospital cardiac arrest (OHCA). After considering the above inclusion criteria, there were 1603 dispatch order forms (0.64% of all dispatch orders) involved in further research.On the basis of the emergency medical procedure forms, the actions of emergency medical teams were verified as medical procedures (endotracheal intubation, the use of suction pumps, defibrillation, the use of alternatives providing airway patency and ROSC was determined.The analysis covered 1603 cases of OHCA. SCA turned out more frequent in men than in women (P = .000). Most often, SCA occurred in domestic conditions during the day and was witnessed by a third person. In 59.9% of the cases, actions were taken by witnesses, which increased the probability of ROSC. Patients were usually intubated (51.4%). Respirators were used less frequently (20.2%). Ventricular fibrillation (VF) was reported only in 22.0% of the cases. The ROSC rate was higher in the group of patients with diagnosed VF than in those with nonshockable rhythms (VF, 55.43% vs asystole, 24.05%; P = .000).Successful resuscitation depends on the quality of emergency medical procedures performed at the place of incident. The highest probability of ROSC is related with defibrillation (in the cases of VF or ventricular tachycardia with no pulse), intubation, the application of a respirator, and performing mechanical ventilation, as well as with a shorter time from dispatch to arrival.

Prehospital advanced airway management for trauma in the United Kingdom: how, when and by whom?

Advanced airway management in the prehospital arena remains controversial. This paper aims to explore some of the evidence and options available and propose a way forward. Options for provision of, and training in, pre-hospital emergency anaesthesia are explored and alternative strategies are discussed. Where classical rapid sequence induction of anaesthesia proves impractical for operational reasons or due to lack of facilities, training opportunities or skills maintenance, a potential ‘silver standard’ is suggested as an alternative.

Safety and feasibility of the laryngeal tube when used by EMTs during out-of-hospital cardiac arrest

BACKGROUND

Ventilation is still one key element of advanced life support. Emergency medical technicians (EMTs) without training in advanced airway management usually use bag valve mask ventilation (BVM). Bag valve mask ventilation requires proper training and yet may be difficult and ineffective. Supraglottic airway devices, such as the laryngeal tube (LT), have been proposed as alternatives. Safety and feasibility are unclear if used by EMTs with limited training only. We compared efficacy of the LT to BVM for out-of-hospital cardiac arrest in a primarily volunteer-based emergency medical services.

METHODS

This is a prospective multicenter observational cohort study. We compared safety (injuries and regurgitation) and feasibility (successful ventilation) in patients who received BVM, LT, or fallback to BVM after LT and controlled for potential confounders using logistic regression.

RESULTS

A total of 517 cases were documented, 395 (76.7%) with LT, 74 (14.4%) with BVM, and 48 (9.3%) where EMTs fell back from LT to BVM. There was no difference between groups regarding demographics (71 ± 17 years; 37% female) and initial rhythm (44% shockable). Placement of LT at first attempt was possible in 300 cases (76%), and at second attempt, in 91 cases (23%). Compared to BVM (22 cases [30%]), ventilation was more frequently successful with LT in 367 cases (93%; adjusted risk ratio, 3.1 [95% confidence interval, 1.3-7.1]; P < .01) and less successful with LT to BVM in 7 cases (15%; 0.3 [0.1-0.7]; P = .01). Five injuries (1.3%) were documented. Regurgitation was observed 8 (11%), 22 (6%; P < .01), and 8 times (17%; P < .01), respectively.

CONCLUSIONS

Use of the LT during out-of-hospital cardiac arrest by EMTs with only basic training appears safe and feasible. Compared to BVM, success rates were higher. Injuries were relatively rare.

Virtual reality in anesthesia "simulation"

Simulation in anesthesia is a field that has revolutionized the teaching outlook. The uncommon grave situations are no more unseen. The ability of these devices to test and give a taste of nerves to an anesthetist is actually preparing him for a safe future management when the need be. The role of simulation in testing a new device for its likely success in clinical world can be foreseen. Mastering a difficult skill no longer subjects a patient to danger. These advanced methods not only see how anesthetist responds to environment, but also how the OT environment reacts to him. The review highlights how technology will help us become technically sound clinicians for tomorrow.

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.

A new risk of facemask ventilation: entrained esophageal air

Facemask ventilation has been associated with the development of postoperative nausea and vomiting, increasing the risk of tracheal aspiration; development of gastric distension that further impairs alveolar ventilation; perforation of gastric and duodenal ulcers; development of pneumothorax; extrabronchial air dissection; and development of cardiac dysrhythmias, including bradycardia from indirect vagal nerve stimulation. An unusual complication that occurred during prolonged facemask ventilation is presented: development of a pseudo-obstruction of the intrathoracic airway due to the presence of entrained esophageal air.

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.

[Comments on the 2010 guidelines on cardiopulmonary resuscitation of the European Resuscitation Council]

ADULTS

Administer chest compressions (minimum 100/min, minimum 5 cm depth) at a ratio of 30:2 with ventilation (tidal volume 500-600 ml, inspiration time 1 s, F(I)O₂ if possible 1.0). Avoid any interruptions in chest compressions. After every single defibrillation attempt (initially biphasic 120-200 J, monophasic 360 J, subsequently with the respective highest energy), chest compressions are initiated again immediately for 2 min independent of the ECG rhythm. Tracheal intubation is the optimal method for securing the airway during resuscitation but should be performed only by experienced airway management providers. Laryngoscopy is performed during ongoing chest compressions; interruption of chest compressions for a maximum of 10 s to pass the tube through the vocal cords. Supraglottic airway devices are alternatives to tracheal intubation. Drug administration routes for adults and children: first choice i.v., second choice intraosseous (i.o.). Vasopressors: 1 mg epinephrine every 3-5 min i.v. After the third unsuccessful defibrillation amiodarone (300 mg i.v.), repetition (150 mg) possible. Sodium bicarbonate (50 ml 8.4%) only for excessive hyperkaliemia, metabolic acidosis, or intoxication with tricyclic antidepressants. Consider aminophylline (5 mg/kgBW). Thrombolysis during spontaneous circulation only for myocardial infarction or massive pulmonary embolism; during on-going cardiopulmonary resuscitation (CPR) only when indications of massive pulmonary embolism. Active compression-decompression (ACD-CPR) and inspiratory threshold valve (ITV-CPR) are not superior to good standard CPR.

CHILDREN

Most effective improvement of outcome by prevention of full cardiorespiratory arrest. Basic life support: initially five rescue breaths, followed by chest compressions (100-120/min depth about one third of chest diameter), compression-ventilation ratio 15:2. Foreign body airway obstruction with insufficient cough: alternate back blows and chest compressions (infants), or abdominal compressions (children >1 year). Treatment of potentially reversible causes: ("4 Hs and 4 Ts") hypoxia and hypovolaemia, hypokalaemia and hyperkalaemia, hypothermia, and tension pneumothorax, tamponade, toxic/therapeutic disturbances, thrombosis (coronary/pulmonary). Advanced life support: adrenaline (epinephrine) 10 µg/kgBW i.v. or i.o. every 3-5 min. Defibrillation (4 J/kgBW; monophasic or biphasic) followed by 2 min CPR, then ECG and pulse check. NEWBORNS: Initially inflate the lungs with bag-valve mask ventilation (p(AW) 20-40 cmH₂O). If heart rate remains <60/min, start chest compressions (120 chest compressions/min) and ventilation with a ratio 3:1. Maintain normothermia in preterm babies by covering them with foodgrade plastic wrap or similar. POSTRESUSCITATION PHASE: Early protocol-based intensive care stabilization; initiate mild hypothermia early regardless of initial cardiac rhythm [32-34°C for 12-24 h (adults) or 24 h (children); slow rewarming (<0.5°C/h)]. Consider percutaneous coronary intervention (PCI) in patients with presumed cardiac ischemia. Prediction of CPR outcome is not possible at the scene, determine neurological outcome <72 h after cardiac arrest with somatosensory evoked potentials, biochemical tests and neurological examination. ACUTE CORONARY SYNDROME: Even if only a weak suspicion of an acute coronary syndrome is present, record a prehospital 12-lead ECG. In parallel to pain therapy, administer aspirin (160-325 mg p.o. or i.v.) and clopidogrel (75-600 mg depending on strategy); in ST-elevation myocardial infarction (STEMI) and planned PCI also prasugrel (60 mg p.o.). Antithrombins, such as heparin (60 IU/kgBW, max. 4000 IU), enoxaparin, bivalirudin or fondaparinux depending on the diagnosis (STEMI or non-STEMI-ACS) and the planned therapeutic strategy. In STEMI define reperfusion strategy depending on duration of symptoms until PCI, age and location of infarction. TRAUMA: In severe hemorrhagic shock, definitive control of bleeding is the most important goal. For successful CPR of trauma patients a minimal intravascular volume status and management of hypoxia are essential. Aggressive fluid resuscitation, hyperventilation and excessive ventilation pressure may impair outcome in patients with severe hemorrhagic shock.

TRAINING

Any CPR training is better than nothing; simplification of contents and processes is the main aim.

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.

In-hospital resuscitation

A recent world expert conference on resuscitation and emergency cardiac care led to evidence-based international guidelines for cardiopulmonary resuscitation (CPR). Several changes to CPR interventions were recommended, and will have to be implemented into clinical practice. The poor prognosis of patients who suffer in-hospital cardiac arrest may be improved with developments in CPR interventions. In the present review the most important changes recommended by the new CPR guidelines and the latest promising CPR investigations are described, focusing on their impact on in-hospital resuscitation.

Alternative airway devices for use in children requiring prehospital airway management: update and case discussion

This manuscript reviews the latest literature on alternative airways for use in children requiring prehospital airway management. Case discussions serve as a springboard for discussion of alternatives to bag-mask ventilation and endotracheal intubation for management of ventilation in infants and children in the prehospital setting. Few airway procedures have been studied with any rigor in this setting, and most of the data that are available are extrapolated from adults. Laryngeal mask airway may be the best alternative airway with the most promise to add to the armamentarium of the prehospital provider, but no controlled trial to date has been conducted.

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.

Airway management outside the operating room

The choice of airway device for resuscitation depends on the skill of the user, the equipment available, the conscious state of the patient, the location of the patient and the probable cause of the cardiorespiratory arrest. Extraglottic airway devices are recommended by the European and American Resuscitation Councils for use when intubation skills are lacking. In this review, we discuss recent research relevant to the use of extraglottic airway devices in resuscitation.

Alternative ventilation strategies in cardiopulmonary resuscitation

The introduction of the 2000 Guidelines for Cardiopulmonary Resuscitation emphasizes a new, evidence-based approach to the science of ventilation during cardiopulmonary resuscitation (CPR). New laboratory and clinical science underemphasizes the role of ventilation immediately after a dysrhythmic cardiac arrest (arrest primarily resulting from a cardiovascular event, such as ventricular defibrillation or asystole). However, the classic airway patency, breathing, and circulation (ABC) CPR sequence remains a fundamental factor for the immediate survival and neurologic outcome of patients after asphyxial cardiac arrest (cardiac arrest primarily resulting from respiratory arrest). The hidden danger of ventilation of the unprotected airway during cardiac arrest either by mouth-to-mouth or by mask can be minimized by applying ventilation techniques that decrease stomach gas insufflation. This goal can be achieved by decreasing peak inspiratory flow rate, increasing inspiratory time, and decreasing tidal volume to approximately 5 to 7 mL/kg, if oxygen is available. Laboratory and clinical evidence recently supported the important role of alternative airway devices to mask ventilation and endotracheal intubation in the chain of survival. In particular, the laryngeal mask airway and esophageal Combitube proved to be effective alternatives in providing oxygenation and ventilation to the patient in cardiac arrest in the prehospital arena in North America. Prompt recognition of supraglottic obstruction of the airway is fundamental for the management of patients in cardiac arrest when ventilation and oxygenation cannot be provided by conventional methods. "Minimally invasive" cricothyroidotomy devices are now available for the professional health care provider who is not proficient or comfortable with performing an emergency surgical tracheotomy or cricothyroidotomy. Finally, a recent device that affects the relative influence of positive pressure ventilation on the hemodynamics during cardiac arrest has been introduced, the inspiratory impedance threshold valve, with the goal of maximizing coronary and cerebral perfusion while performing CPR. Although the role of this alternative ventilatory methodology in CPR is rapidly being established, we cannot overemphasize the need for proper training to minimize complications and maximize the efficacy of these new devices.