Prehospital standardization of medical airway management: incidence and risk factors of difficult airway

Swedish consensus regarding difficult pre-hospital airway management: a Delphi study

BACKGROUND

The aim of this study was to establish a consensus among experts in prehospital work regarding the management of difficult airways in prehospital care in Sweden. The results were subsequently used to develop an algorithm for handling difficult airway in prehospital care, as there was none available in Sweden prior to this study.

METHODS

This two-round Delphi study was conducted by forming an expert panel comprising anesthesiologists and anesthesia nurses working in prehospital setting in Sweden. The expert panel responded digital forms with questions and statements related to airway management. The study continued until consensus was reached, defined as more than 70% agreement. The study took place from December 4, 2021, to May 15, 2022.

RESULTS

In the first round, 74 participants took part, while the second round involved 37 participants. Consensus was reached in 16 out of 17 statements. 92% of the participants agreed that an airway algorithm adapted for prehospital use is necessary.

CONCLUSIONS

The capacity to adapt the approach to airway management based on specific pre-hospital circumstances is crucial. It holds significance to establish a uniform framework that is applicable across various airway management scenarios. Consequently, the airway management algorithm that has been devised should be regarded as a recommendation, allowing for flexibility rather than being interpreted as a rigid course of action. This represents the inaugural nationwide algorithm for airway management designed exclusively for pre-hospital operations in Sweden. The algorithm is the result of a consensus reached by experts in pre-hospital care.

Efficacy of endotracheal intubation in helicopter cabin vs. ground: a systematic review and meta-analysis

BACKGROUND

Pre-hospital endotracheal intubation (ETI) is a sophisticated procedure with a comparatively high failure rate. Especially, ETI in confined spaces may result in higher difficulty, longer times, and a higher failure rate. This study analyses if Helicopter Emergency Medical Services (HEMS) intubation (time-to) success are influenced by noise, light, and restricted space in comparison to ground intubation. Available literature reporting these parameters was very limited, thus the reported differences between ETI in helicopter vs. ground by confronting parameters such as time to secure airway, first pass success rate and Cormack-Lehane Score were analysed.

METHODS

A systematic review and meta-analysis were conducted using PUBMED, EMBASE, Cochrane Library, and Ovid on October 15th, 2022. The database search provided 2322 studies and 6 studies met inclusion and quality criteria. The research was registered with the International Prospective Register of Systematic Reviews (CRD42022361793).

RESULTS

A total of six studies were selected and analysed as part of the systematic review and meta-analysis. The first pass success rate of ETI was more likely to fail in the helicopter setting as compared to the ground (82,4% vs. 87,3%), but the final success rate was similar between the two settings (96,8% vs. 97,8%). The success rate of intubation in literature was reported higher in physician-staffed HEMS than in paramedic-staffed HEMS. The impact of aircraft type and location inside the vehicle on intubation success rates was inconclusive across studies. The meta-analysis revealed inconsistent results for the mean duration of intubation, with one study reporting shorter intubation times in helicopters (13,0s vs.15,5s), another reporting no significant differences (16,5s vs. 16,8s), and a third reporting longer intubation times in helicopters (16,1s vs. 15,0s).

CONCLUSION

Further research is needed to assess the impact of environmental factors on the quality of ETI on HEMS. While the success rate of endotracheal intubation in helicopters vs. on the ground is not significantly different, the duration and time to secure the airway, and Cormack-Lehane Score may be influenced by environmental factors. However, the limited number of studies reporting on these factors highlights the need for further research in this area.

Predictive and protective factors for failing first pass intubation in prehospital rapid sequence intubation: an aetiology and risk systematic review with meta-analysis

BACKGROUND

Prehospital rapid sequence intubation first pass success rates vary between 59% and 98%. Patient morbidity is associated with repeat intubation attempts. Understanding what influences first pass success can guide improvements in practice. We performed an aetiology and risk systematic review to answer the research question 'what factors are associated with success or failure at first attempt laryngoscopy in prehospital rapid sequence intubation?'.

METHODS

MEDLINE, EMBASE, CINAHL, and Cochrane Library were searched on March 3, 2023 for studies examining first pass success rates for rapid sequence intubation of prehospital live patients. Screening was performed via Covidence, and data synthesised by meta-analysis. The review was registered with PROSPERO and performed and reported as per Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

Reasonable evidence was discovered for predictive and protective factors for failure of first pass intubation. Predictive factors included age younger than 1 yr, the presence of blood or fluid in the airway, restricted jaw or neck movement, trauma patients, nighttime procedures, chronic or acute distortions of normal face/upper airway anatomy, and equipment issues. Protective factors included an experienced intubator, adequate training, use of certain videolaryngoscopes, elevating the patient on a stretcher in an inclined position, use of a bougie, and laryngeal manoeuvres.

CONCLUSIONS

Managing bloody airways, positioning well, using videolaryngoscopes with bougies, and appropriate training should be further explored as opportunities for prehospital services to increase first pass success. Heterogeneity of studies limits stronger conclusions.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO (CRD42022353609).

A Predictor of Difficult Airway: The Tasli Classification in Transnasal Flexible Laryngoscopy

INTRODUCTION

Difficult airway is defined as difficulty or failure in one or more steps in upper airway management. Evaluation of the upper airway with physical examination methods and endoscopic devices is crucial in predicting difficult airway. The aim of this study was to evaluate bedside tests, Cormack Lehane (CL) and Tasli Classification (TC) scores of the patients and it was aimed to reveal the role of TC which will be performed preoperatively as a predictor of difficult tracheal intubation (DTI).

METHODS

The study included a total of 98 patients who underwent surgical treatment under general anesthesia. Demographic data, including age, gender, and body mass index (BMI), and bedside tests consisting Modified Mallampati Classification (MMC), thyromental (TD) and sternomental (SD) distances, neck circumference (NC), interincisor distance (IID), CL and TC were recorded.

RESULTS

Evaluation was made of 64 (65.3%) male and 34 (34.7%) female patients ranging in age from 18 to 84 years (mean age: 50.35 ± 0.47 years). The successfully intubated patients (SIP)  group comprised 68 (69.4%) patients, and the difficult intubation patients (DIP) group, 30 (30.6%). According to CL, the numbers of SIP and DIP constituting grade 1 was 29 (42.6%) and one (3.3%); grade 2a was 29 (42.6%) and one (3.3%); grade 2b was eight (11.8%) and three (10%); grade 3a was one (1.5%) and six (20%); grade 3b was one (1.5%) and 14 (46.7%) respectively. Grade 4 was only detected in the DIP group in 5 (16.7%) patients. According to TC, the numbers of SIP and DIP constituting grade 1 was 20 (29.4%) and 1 (3.3%); grade 2a was 37 (54.4%) and seven (23.3%); grade 2b was 10 (14.7%) and 18 (60%); grade 3 was one (1.5%) and two (6.7%) respectively. Grade 4 was only detected in the DIP group in two (6.7%) patients.

CONCLUSION

The TC, CL, NC and BMI scores were higher in the DIP group and higher TC scores (grade 2b, 3, and 4) can be a predictor of difficult airway. However, it may be more beneficial to use TC as a complementary diagnostic tool with bedside tests such as NC, SM, TM and MMC, rather than used alone.

Clinical Research in Prehospital Care: Current and Future Challenges

Prehospital care plays a critical role in improving patient outcomes, particularly in cases of time-sensitive emergencies such as trauma, cardiac failure, stroke, bleeding, breathing difficulties, systemic infections, etc. In recent years, there has been a growing interest in clinical research in prehospital care, and several challenges and opportunities have emerged. There is an urgent need to adapt clinical research methodology to a context of prehospital care. At the same time, there are many barriers in prehospital research due to the complex context, posing unique challenges for research, development, and evaluation. Among these, this review allows the highlighting of limited resources and infrastructure, ethical and regulatory considerations, time constraints, privacy, safety concerns, data collection and analysis, selection of a homogeneous study group, etc. The analysis of the literature also highlights solutions such as strong collaboration between emergency medical services (EMS) and hospital care, use of (mobile) health technologies and artificial intelligence, use of standardized protocols and guidelines, etc. Overall, the purpose of this narrative review is to examine the current state of clinical research in prehospital care and identify gaps in knowledge, including the challenges and opportunities for future research.

Detecting cervical esophagus with ultrasound on healthy voluntaries: learning curve

BACKGROUND

The objective of this study was to determine the learning curve of tracheal-esophageal ultrasound by prehospital medical and paramedical staff.

METHODS

A single-center prospective study was carried out at a French EMS (SAMU 92). Volunteer participants first received a short theoretical training through e-learning, followed by two separate hands-on workshops on healthy volunteers, spaced one to two months apart. Learners were timed to obtain the tracheal-esophageal ultrasound target image 10 consecutive times. The first workshop was intended to perform a learning curve, and the second was to assess unlearning. The secondary objectives were to compare performance by profession and by previous ultrasound experience.

RESULTS

We included 32 participants with a mean age of 38 (± 10) years, consisting of 56% men. During the first workshop, the target image acquisition time was 20.4 [IQR: 10.6;41] seconds on the first try and 5.02 [3.72;7.5] seconds on the 10th (p < 0.0001). The image acquisition time during the second workshop was shorter compared to the first one (p = 0.016). In subgroup analyses, we found no significant difference between physicians and nurses (p = 0.055 at the first workshop and p = 0.164 at the second) or according to previous ultrasound experience (p = 0.054 at the first workshop and p = 0.176), counter to multivariate analysis (p = 0.02).

CONCLUSIONS

A short web-based learning completed by a hands-on workshop made it possible to obtain the ultrasound image in less than 10 s, regardless of the profession or previous experience in ultrasound.

Success rate of prehospital emergency front-of-neck access (FONA): a systematic review and meta-analysis

BACKGROUND

Front-of-neck access (FONA) is an emergency procedure used as a last resort to achieve a patent airway in the prehospital environment. In this systematic review with meta-analysis, we aimed to evaluate the number and success rate of FONA procedures in the prehospital setting, including changes since 2017, when a surgical technique was outlined as the first-line prehospital method.

METHODS

A systematic literature search (PROSPERO CRD42022348975) was performed from inception of databases to July 2022 to identify studies in patients of any age undergoing prehospital FONA, followed by data extraction. Meta-analysis was used to derive pooled success rates. Methodological quality of included studies was interpreted using the Cochrane risk of bias tool, and rated using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

RESULTS

From 909 studies, 69 studies were included (33 low quality; 36 very low quality) with 3292 prehospital FONA attempts described (1229 available for analysis). The crude median success rate increased from 99.2% before 2017 to 100.0% after 2017. Meta-analysis revealed a pooled overall FONA success rate of 88.0% (95% confidence interval [CI], 85.0-91.0%). Surgical techniques had the highest success rate at a median of 100.0% (pooled rate=92.0%; 95% CI, 88.0-95.0%) vs 50.0% for needle techniques (pooled rate=52.0%; 95% CI, 28.0-76.0%).

CONCLUSIONS

Despite being a relatively rare procedure in the prehospital setting, the success rate for FONA is high. A surgical technique for FONA appears more successful than needle techniques, and supports existing UK prehospital guidelines.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO CRD42022348975.

Factors associated with tracheal intubation-related complications in the prehospital setting: a prospective multicentric cohort study

Background Emergency tracheal intubation is routinely performed in the prehospital setting. Airway management in the prehospital setting has substantial challenges. Objective The aim of the present study was to determine risk factors predicting tracheal intubation-related complications on the prehospital field. Setting A prospective, multicentric, cohort study which was conducted in three mobile ICUs (MICUs; service mobile d'urgence et de réanimation).Outcome measures and analysis Tracheal intubation-related complications were defined as the occurrence of at least one of the following events: oxygen desaturation (SpO2 < 90%) during tracheal intubation, aspiration (regurgitation visualized during laryngoscopy), and vomiting. Difficult intubation was defined as more than two failed direct laryngoscopic attempts, or the need for any alternative tracheal intubation method. Multivariate logistic regressions were used. Results During the 5-year study period, 1915 consecutive patients were intubated in the MICUs participating in the study. Overall, 1287 (70%) patients were successfully intubated after the first laryngoscopic attempt, with rates of 90, 74, 42, and 30% for Cormack-Lehane grade 1, 2, 3, and 4, respectively. Tracheal intubation was difficult in 663 cases (36%). Tracheal intubation-related complications occurred in 267 (14%) patients. In the multivariate analysis, we found that the leading risk factors for tracheal intubation-related complications were Cormack and Lehane grade 3 and 4 [odds ratio (OR) = 1.65; 95% confidence interval (CI), 1.05-2.61; and OR = 2.79; 95% CI, 1.56-4.98, respectively], a BMI of more than 30 (OR = 1.61; 95% CI, 1.13-2.28), when intubation was difficult (OR = 1.72; 95% CI, 1.15-2.57), and when tracheal intubation required more than one operator (OR = 2.30; 95% CI, 1.50-3.49).Conclusions In this prospective study, we found that Cormack and Lehane more than grade 2, BMI >30, difficult intubation, and tracheal intubation requiring more than one operator were all independent predictors of tracheal intubation-related complications in the prehospital setting. When these risk factors are identified on scene, adapted algorithms that anticipate the use of a bougie should be generalized to reduce morbidity on the prehospital field.

Pre-hospital guidelines for CPR-Induced Consciousness (CPRIC): A scoping review

Background

CPR-Induced Consciousness is an emerging phenomenon with a paucity of consensus guidelines from peak resuscitative bodies. Local prehospital services have had to implement their own CPR-Induced Consciousness guidelines. This scoping review aims to identify prehospital CPR-Induced Consciousness guidelines and compare or contrast their management options.

Objective

The purpose of this scoping review is to identify and compare as many prehospital CPR-Induced Consciousness guidelines as feasible, highlight common management trends, and discuss the factors that might impact CPR-Induced Consciousness guidelines and the management trends identified.

Design

To search for prehospital CPR-Induced Consciousness guidelines, a bibliographical search of five databases was undertaken (MEDLINE, EMBASE, Cochrane, Scopus, and CINAHL plus). Also included was a grey literature search arm, comprised of four search strategies: 1. Customised Google search, 2. Hand searching of targeted websites, 3. Grey literature databases, 4. Consultation with subject experts.

Results

Our search extracted 23 prehospital CPR-Induced Consciousness guidelines and one good practise statement from the International Liaison Committee on Resuscitation. Of the 23 prehospital guidelines available, we identified 20 different ways of treating CPR-Induced Consciousness. Midazolam was the most frequently used drug to treat CPR-Induced Consciousness (14/23, 61%), followed by Ketamine (11/23, 48%) and Fentanyl (9/23, 39%).

Conclusion

Prehospital CPR-Induced Consciousness guidelines are both exceptionally uncommon and vary substantially from each other. This has a flow-on effect towards data collection and only serves to continue CPR-Induced Consciousness's relatively unknown status surrounding both knowledge of, and the effect CPR-Induced Consciousness treatment has on cardiac arrest outcomes.

Intraoperative Accidental Extubation during Thyroidectomy in a Known Difficult-Airway Patient: An Adult Simulation Case for Anesthesiology Residents

Intraoperative accidental extubation on a known difficult-airway patient requires prompt attention. A good understanding of the steps to re-establish the airway is critical, especially when the patient is known to have a difficult airway documented or discovered on induction or acquires a difficult airway secondary to intraoperative events. The situation becomes even more complicated if the case has been handed off to another anesthesiologist, where specific and detailed information may not have been conveyed. This simulation was designed to train first-year clinical anesthesia residents. It was a 50 min encounter that focused on the management of complete loss of an airway during a thyroidectomy on a known difficult-airway patient. The endotracheal tube dislodgement was simulated by deliberate tube manipulation through the cervical access window of the mannequin. Learners received a formative assessment of their performance during the debrief, and most of the residents met the educational objectives. Learners were asked to complete a survey of their experience, and the feedback was positive and constructive. The response rate was 68% (17/25). Our simulation program helped anesthesiology residents develop intraoperative emergency airway management skills in a safe environment, as well as foster communication skills among anesthesiologists and the surgery team.

Approaching the airway in prehospital emergency is a common and potentially life-saving practice

Management by the environment is complex, which means a much higher percentage of difficult airways than in a regulated environment such as the operating room. Failure or prolonged attempt to tracheal intubation is associated with unfavorable outcomes and serious complications. Acute epiglottitis is a life-threatening disorder, classified as a medical emergency within the diseases of the upper respiratory airway and characterized by its sudden and deadly evolution if rapid intubation is not achieved to allow oxygenation of the patient. We describe a 36-year-old male patient with stridor, dyspnea e hypoxemia due to total obstruction of airway, caused by an acute epiglottitis. We aim to highlight this unusual injury and its management from the prehospital until discharge illustrating the severity of the clinical presentation, current treatment and outcome.

Prehospital Surgical Airway Management: An NAEMSP Position Statement and Resource Document

Bag-valve-mask ventilation and endotracheal intubation have been the mainstay of prehospital airway management for over four decades. Recently, supraglottic device use has risen due to various factors. The combination of bag-valve-mask ventilation, endotracheal intubation, and supraglottic devices allows for successful airway management in a majority of patients. However, there exists a small portion of patients who are unable to be intubated and cannot be adequately ventilated with either a facemask or a supraglottic airway. These patients require an emergent surgical airway. A surgical airway is an important component of all airway algorithms, and in some cases may be the only viable approach; therefore, it is imperative that EMS agencies that are credentialed to manage airways have the capability to perform surgical airways when appropriate. The National Association of Emergency Medical Services Physicians (NAEMSP) recommends the following for emergency medical services (EMS) agencies that provide advanced airway management.A surgical airway is reasonable in the prehospital setting when the airway cannot be secured by less invasive means.When indicated, a surgical airway should be performed without delay.A surgical airway is not a substitute for other airway management tools and techniques. It should not be the only rescue option available.Success of an open surgical approach using a scalpel is higher than that of percutaneous Seldinger techniques or needle-jet ventilation in the emergency setting.

Le mandrin long béquillé : est-ce systématique ?

L’intubation trachéale (IT) est un geste fréquent en médecine d’urgence extra-hospitalière (MUEH) mais elle est associée à un taux élevé d’échec de la première tentative et à certaines complications graves. Le taux de ces dernières augmente avec le nombre de tentative d’IT. La Société française d’anesthésie et de réanimation (SFAR) et la Société de réanimation de langue française (SRLF) avec la collaboration de la Société française de médecine d’urgence (SFMU) ont publié en 2016 des recommandations formalisées d’experts (RFE) sur l’intubation du patient de réanimation. La question qui se pose est la pertinence de ces recommandations pour la MUEH. En effet, la mesure du risque de difficulté est basée sur le score de MACOCHA et en cas de difficulté prévue les outils à utiliser d’emblée sont le vidéo-laryngoscope ou le mandrin long béquillé en laryngoscopie directe. Or il apparait que le score de MACOCHA n’est pas adapté à la MUEH et de façon plus générale, il est complexe de mesurer le risque d’intubation difficile (ID) dans ce contexte. La vidéolaryngoscopie n’a pas encore fait la preuve de sa supériorité par rapport à la laryngoscopie directe en MUEH. Par contre des travaux récents en médecine d’urgence ont démontré que l’utilisation en première intention du mandrin long béquillé augmente significativement le taux de succès de la première tentative de l’IT, même en l’absence de facteur de risque d’ID. Au total, on pourrait considérer chaque IT en MUEH comme a priori à risque de difficulté ce qui justifierait une utilisation d’emblée du mandrin long béquillé. Il semble nécessaire de proposer des recommandations spécifiques à la médecine d’urgence.

Pre-hospital emergency anaesthesia in trauma patients treated by anaesthesiologist and nurse anaesthetist staffed critical care teams

Background

Pre‐hospital tracheal intubation in trauma patients has recently been questioned. However, not only the trauma and patient characteristics but also airway provider competence differ between systems making simplified statements difficult.

Method

The study is a subgroup analysis of trauma patients included in the PHAST study. PHAST was a prospective, observational, multicentre study on pre‐hospital advanced airway management by anaesthesiologist and nurse anaesthetist manned pre‐hospital critical care teams in the Nordic countries May 2015‐November 2016. Endpoints include intubation success rate, complication rate (airway‐related complication according to Utstein Airway Template by Sollid et al), scene time (time from arrival of the critical care team to departure of the patient) and pre‐hospital mortality.

Result

The critical care teams intubated 385 trauma patients, of which 65 were in shock (SBP <90 mm Hg), during the study. Of the trauma patients, 93% suffered from blunt trauma, the mean GCS was 6 and 75% were intubated by an experienced provider who had performed >2500 tracheal intubations. The pre‐hospital tracheal intubation overall success rate was 98.6% and the complication rate was 13.6%, with no difference between patients with or without shock. The mean scene time was significantly shorter in trauma patients with shock (21.4 min) compared to without shock (21.4 vs 25.1 min). Following pre‐hospital tracheal intubation, 97% of trauma patients without shock and 91% of the patients in shock with measurable blood pressure were alive upon arrival to the ED.

Conclusion

Pre‐hospital tracheal intubation success and complication rates in trauma patients were comparable with in‐hospital rates in a system with very experienced airway providers. Whether the short scene times contributed to a low pre‐hospital mortality needs further investigation in future studies.

Approaching the airway in prehospital emergency is a common and potentially life-saving practice

Management by the environment is complex, which means a much higher percentage of difficult airways than in a regulated environment such as the operating room. Failure or prolonged attempt to tracheal intubation is associated with unfavorable outcomes and serious complications. Acute epiglottitis is a life-threatening disorder, classified as a medical emergency within the diseases of the upper respiratory airway and characterized by its sudden and deadly evolution if rapid intubation is not achieved to allow oxygenation of the patient. We describe a 36-year-old male patient with stridor, dyspnea e hypoxemia due to total obstruction of airway, caused by an acute epiglottitis. We aim to highlight this unusual injury and its management from the prehospital until discharge illustrating the severity of the clinical presentation, current treatment and outcome.

Incidence, Complications, and Factors Associated with Out-of-Hospital First Attempt Intubation Failure in Adult Patients: A Secondary Analysis of the CURASMUR Trial Data

Objectives: The objectives of this study were to evaluate first attempt intubation failure rate, its associated factors, and its related complications in out-of-hospital emergency setting, when emergency physicians perform standardized airway management using rapid sequence intubation in adult patients. Material and methods: The present study was a substudy of the Succinylcholine versus Rocuronium for out-of-hospital Emergency Intubation (CURASMUR) Trial, which compared Succinylcholine and Rocuronium used for Rapid sequence intubation. First attempt Intubation failure rate and early intubation related complications were recorded. We used multivariable logistic regression analysis to determine first intubation failure associated factors. Results: A total of 1230 patients were included with mean age of 55.9 +/- 19 years. First attempt intubation failure was recorded in 285 (23.2%) patients. The occurrence of a first attempt intubation failure was independently associated with history of ear, nose, and throat neoplasia (OR 2.20, CI 95% 1.06-4.60). Early intubation related complications were more frequent in case of first attempt intubation failure: 80 of 285 (28.4%) in patients with first attempt intubation failure and 185 of 945 (19.6%) in patients with successful first attempt intubation [OR 1.44; CI 95%, 1.11-1.87]. Conclusion: Based on a large multicenter study on out-of-hospital tracheal intubation of adult patients, we found that first attempt intubation failure rate was high and that history of ear, nose, and throat (ENT) neoplasia was an independent associated factor. Failure in first intubation attempt was associated with significantly more intubation related complications.

Emergency Department Versus Operating Suite Intubation in Operative Trauma Patients: Does Location Matter?

BACKGROUND

Decreasing the time from patient arrival to definitive surgical care in injured patients requiring an operation improves outcomes. We sought to study the effect of intubation location (emergency department versus operating suite) on time to definitive surgical care. We hypothesized that patients requiring emergency surgical interventions intubated in the emergency department would have shorter times to definitive care when compared to patients intubated in the operating suite.

METHODS

All injured patients with a preoperative emergency department dwell time of less than 30 min and undergoing emergency operative procedures with the trauma surgery service at an urban Level I center (2010-2017) were analyzed. Demographics, clinical variables, and outcomes were assessed in relation to emergency department intubation versus operating suite intubation. The primary study endpoint was time to initiation of definitive surgical care, defined as the total elapsed time from emergency department arrival until operating room incision time. To investigate the relationship between clinical variables and time, multivariable regression was performed.

RESULTS

In total, 241 patients were included. In total, 138 patients were intubated in the emergency department and 103 patients were intubated in the operative suite. There was no difference between patients intubated in the emergency department and those intubated in the operating room with respect to age, gender, injury mechanism, initial heart rate or systolic blood pressure. Emergency department patients were more likely to sustain post-intubation, traumatic cardiopulmonary arrest (8.0 vs. 0.9%; p = 0.014). No statistical difference in total elapsed time from arrival to definitive surgical care was appreciated between study groups (41 vs. 43 min; p = 0.064). After controlling for clinical variables, emergency department intubation was not associated with time to definitive care (p = 0.386) in the multiple variable regression analysis.

CONCLUSION

When emergency department and operative suite intubation patients were compared, emergency department intubation did not decrease total elapsed time until definitive surgery but was associated with post-intubation, traumatic cardiopulmonary arrest.

Feasibility of Prehospital Rapid Sequence Intubation in the Cabin of an AW169 Helicopter

OBJECTIVE

Prehospital rapid sequence intubation (RSI) is an important aspect of prehospital care for helicopter emergency medical services (HEMS). This study examines the feasibility of in-aircraft (aircraft on the ground) RSI in different simulated settings.

METHODS

Using an AW169 aircraft cabin simulator at Air Ambulance Kent Surrey Sussex, 3 clinical scenarios were devised. All required RSI in a "can intubate, can ventilate" (easy variant) and a "can't intubate, can't ventilate" scenario (difficult variant). Doctor-paramedic HEMS teams were video recorded, and elapsed times for prespecified end points were analyzed.

RESULTS

Endotracheal intubation (ETI) was achieved fastest outside the simulator for the easy variant (median = 231 seconds, interquartile range = 28 seconds). Time to ETI was not significantly longer for in-aircraft RSI compared with RSI outside the aircraft, both in the easy (p = .14) and difficult variant (p = .50). Wearing helmets with noise distraction did not impact the time to intubation when compared with standard in-aircraft RSI, both in the easy (p = .28) and difficult variant (p = .24).

CONCLUSION

In-aircraft, on-the-ground RSI had no significant impact on the time to successful completion of ETI. Future studies should prospectively examine in-cabin RSI and explore the possibilities of in-flight RSI in civilian HEMS services.

Spectral Reflectance Can Differentiate Tracheal and Esophageal Tissue in the Presence of Bodily Fluids and Soot

Endotracheal intubation is a common life-saving procedure implemented in emergency care to ensure patient oxygenation, but it is difficult and often performed in suboptimal conditions leading to high rates of patient complications. Undetected misplacement in the esophagus is a preventable complication that can lead to fatalities in 5–10% of patients who undergo emergency intubation. End-tidal carbon dioxide monitoring and other proper placement detection methods are useful, yet the problem of misplacement persists. Our previous work demonstrated the utility of spectral reflectance sensors for differentiating esophageal and tracheal tissues, which can be used to confirm proper endotracheal tube placement. In this study, we examine the effectiveness of spectral characterization in the presence of saline, blood, “vomit”, and soot in the trachea. Our results show that spectral properties of the trachea that differentiate it from the esophagus persist in the presence of these substances. This work further confirms the potential usefulness of this novel detection technology in field applications.

Data quality of Glasgow Coma Scale and Systolic Blood Pressure in scientific studies involving physician-staffed emergency medical services: Systematic review

BACKGROUND

Emergency physicians on-scene provide highly specialized care to severely sick or injured patients. High-quality research relies on the quality of data, but no commonly accepted definition of EMS data quality exits. Glasgow Coma Score (GCS) and Systolic Blood Pressure (SBP) are core physiological variables, but little is known about the quality of these data when reported in p-EMS research. This systematic review aims to describe the quality of pre-hospital reporting of GCS and SBP data in studies where emergency physicians are present on-scene.

METHODS

A systematic literature search was performed using CINAHL, Cochrane, Embase, Medline, Norart, Scopus, SweMed + and Web of Science, in accordance with the PRISMA guidelines. Reported data on accuracy of reporting, completeness and capture were extracted to describe the quality of documentation of GCS and SBP. External and internal validity assessment was performed by extracting a set of predefined variables.

RESULTS

We included 137 articles describing data collection for GCS, SBP or both. Most studies (81%) were conducted in Europe and 59% of studies reported trauma cases. Reporting of GCS and SBP data were not uniform and may be improved to enable comparisons. Of the predefined external and internal validity data items, 26%-45% of data were possible to extract from the included papers.

CONCLUSIONS

Reporting of GCS and SBP is variable in scientific papers. We recommend standardized reporting to enable comparisons of p-EMS.

[Airway management in preclinical emergency anesthesia with respect to specialty and education]

BACKGROUND AND OBJECTIVE

Difficult airway management is a key skill in preclinical emergency medicine. A lower rate of subjective difficult airways and an increased success rate of endotracheal intubation have been reported for highly trained emergency physicians. The aim of this study was therefore to analyze the effect for different specialists and the individual state of training in the German emergency medical system.

MATERIAL AND METHODS

In a retrospective register analysis of 6024 preclinical anesthesia procedures, the frequencies of airway devices, neuromuscular blocking agents, capnography and difficult airways were analyzed with respect to specialization and status of training. Additionally, low, medium and highly experienced emergency physicians in airway management were summarized by specialization and status of training according to the Dreyfus model of skill acquisition and compared.

RESULTS

The incidence of subjective difficult airway situations was 10% for anesthesiological emergency physicians compared to 15-20% for other disciplines. The latter used supraglottic airway devices more often (7-9% vs. 4%) and video laryngoscopes less often (3% vs. 5%) compared to anesthesiological emergency physicians. The discipline-related state of training was inhomogeneous and revealed a reduced rate of supraglottic airway devices for internal specialists with further training (10% vs. 2%). Anesthetists specialized in intensive care medicine used capnography less frequently compared to other anesthetists (79% vs. 72%). With higher levels of experience in airway management, the frequency of endotracheal intubation (86% vs. 94%), neuromuscular blocking agents (59% vs. 73%) and video laryngoscopy (3% vs. 6%) increased and the incidence of subjective difficult airway situations (16% vs. 10%) decreased.

CONCLUSION

The level of training in airway management especially for non-anesthetists is inhomogeneous. The recently published German S1 guidelines for prehospital airway management recommend education and training as well as the primary use of the video laryngoscope with Macintosh blade. The implementation could lower the incidence of subjective difficult airways.

Effect of Rocuronium vs Succinylcholine on Endotracheal Intubation Success Rate Among Patients Undergoing Out-of-Hospital Rapid Sequence Intubation: A Randomized Clinical Trial

IMPORTANCE

Rocuronium and succinylcholine are often used for rapid sequence intubation, although the comparative efficacy of these paralytic agents for achieving successful intubation in an emergency setting has not been evaluated in clinical trials. Succinylcholine use has been associated with several adverse events not reported with rocuronium.

OBJECTIVE

To assess the noninferiority of rocuronium vs succinylcholine for tracheal intubation in out-of-hospital emergency situations.

DESIGN, SETTING AND PARTICIPANTS

Multicenter, single-blind, noninferiority randomized clinical trial comparing rocuronium (1.2 mg/kg) with succinylcholine (1 mg/kg) for rapid sequence intubation in 1248 adult patients needing out-of-hospital tracheal intubation. Enrollment occurred from January 2014 to August 2016 in 17 French out-of-hospital emergency medical units. The date of final follow-up was August 31, 2016.

INTERVENTIONS

Patients were randomly assigned to undergo tracheal intubation facilitated by rocuronium (n = 624) or succinylcholine (n = 624).

MAIN OUTCOMES AND MEASURES

The primary outcome was the intubation success rate on first attempt. A noninferiority margin of 7% was chosen. A per-protocol analysis was prespecified as the primary analysis.

RESULTS

Among 1248 patients who were randomized (mean age, 56 years; 501 [40.1%] women), 1230 (98.6%) completed the trial and 1226 (98.2%) were included in the per-protocol analysis. The number of patients with successful first-attempt intubation was 455 of 610 (74.6%) in the rocuronium group vs 489 of 616 (79.4%) in the succinylcholine group, with a between-group difference of -4.8% (1-sided 97.5% CI, -9% to ∞), which did not meet criteria for noninferiority. The most common intubation-related adverse events were hypoxemia (55 of 610 patients [9.0%]) and hypotension (39 of 610 patients [6.4%]) in the rocuronium group and hypoxemia (61 of 616 [9.9%]) and hypotension (62 of 616 patients [10.1%]) in the succinylcholine group.

CONCLUSIONS AND RELEVANCE

Among patients undergoing endotracheal intubation in an out-of-hospital emergency setting, rocuronium, compared with succinylcholine, failed to demonstrate noninferiority with regard to first-attempt intubation success rate.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02000674.

A pilot study on using Suction-Assisted Laryngoscopy Airway Decontamination techniques to assist endotracheal intubation by GlideScope® in a manikin simulating massive hematemesis

Background:

The Suction-Assisted Laryngoscopy and Airway Decontamination techniques are newly designed emergency airway management skills to assist endotracheal intubation with the complementary use of suction catheters and video laryngoscopes in patients with severe vomiting or massive hematemesis.

Objectives:

To evaluate the performance of emergency department doctors in using the two Suction-Assisted Laryngoscopy and Airway Decontamination techniques (level 1 and level 2) to assist endotracheal intubation by GlideScope® in an airway manikin simulating massive hematemesis, the Nasco airway decontamination simulator.

Methods:

A total of 30 emergency department doctors were recruited in a pilot study. Their performance of using two levels of Suction-Assisted Laryngoscopy and Airway Decontamination techniques (Suction-Assisted Laryngoscopy and Airway Decontamination 1 and Suction-Assisted Laryngoscopy and Airway Decontamination 2) with two different suction catheters, the DuCanto suction catheter and Yankauer suction catheter, were compared with the conventional suction technique. The failed endotracheal intubation rates, time for intubation and number of attempts, amount of aspirated fluid, and the subjective ease of different methods by the participants were compared.

Results:

Irrespective the choice of suction catheter, endotracheal intubation in the manikin by using Suction-Assisted Laryngoscopy and Airway Decontamination 1 had the lowest failure rate which is much better than conventional suction technique (p = 0.012), smaller amount of aspiration compared with the conventional suction technique (p = 0.027), and comparable intubation time with the conventional suction technique (p = 0.850). Most participants were able to intubate the manikin successfully in the first attempt by Suction-Assisted Laryngoscopy and Airway Decontamination 1 with the DuCanto suction catheter, and they were of the opinion that such combination was the most preferred in performing endotracheal intubation.

Conclusion:

Suction-Assisted Laryngoscopy and Airway Decontamination 1 has the best performance in this manikin study, and Suction-Assisted Laryngoscopy and Airway Decontamination 1 with the DuCanto suction catheter was the most favorable method for endotracheal intubation in this manikin study by the participants.

Difficult airway management algorithms: a directed review

The primary aim of this study was to identify, describe and compare the content of existing difficult airway management algorithms. Secondly, we aimed to describe the literature reporting the implementation of these algorithms. A directed search across three databases (MEDLINE, Embase and Scopus) was performed. All articles were screened for relevance to the research aims and according to pre-determined exclusion criteria. We identified 38 published airway management algorithms. Our results show that most facemask employ a four-step process as represented by a flow chart, with progression from tracheal intubation, facemask ventilation and supraglottic airway device use, to a rescue emergency surgical airway. The identified algorithms are overwhelmingly similar, yet many use differing terminology. The frequency of algorithm publication has increased recently, yet adherence and implementation outcome data remain limited. Our results highlight the lack of a single algorithm that is universally endorsed, recognised and applicable to all difficult airway management situations.

[Preclinical emergency anesthesia : A current state analysis from 2015-2017]

BACKGROUND AND OBJECTIVE

Due to multiple factors the performance of preclinical emergency anesthesia is fraught with risks even for experienced emergency physicians. In order to support emergency physicians in monitoring and management of anesthesia, the German practice management guidelines for preclinical emergency anesthesia in adults were published in 2015; however, current data on adherence to the guidelines are not available.

MATERIAL AND METHODS

In a retrospective register analysis of preclinical anesthesia from 2015-2017 in Baden-Württemberg, the recorded anesthetic agents, monitoring, airway management and medical disciplines of emergency physicians were analyzed. The anesthetic agents utilized were compared to the emergency scenarios in the guidelines (e.g. cardiac patients, patients with acute respiratory insufficiency or acute neurological disorder and trauma patients).

RESULTS

Midazolam and propofol were predominantly used in the 12,605 cases of preclinical emergency anesthesia evaluated. The adherence to the guidelines was 35% for cardiac patients, 51% for patients with acute respiratory insufficiency or 52% for acute neurological disorders and 79% for trauma patients. Securing the airway was carried out in 88.5 % with endotracheal intubation (capnography 79%). Discipline-related differences occurred in airway management for the devices used, capnography, muscle relaxation and the frequency of the subjectively difficult airway. A higher adherence for trauma patients and patients with acute neurological disorders was found for emergency physicians who were anesthesiologists compared to non-anesthesiologists.

CONCLUSION

The study of the current state of preclinical emergency anesthesia in Germany showed a deficient implementation of the pharmacological recommendations for action except for trauma patients. Reasons for divergence could arise due to different availability of rescue equipment, training concepts or discipline of emergency physicians. Suitable education and training could improve the quality of prehospital anesthesia in Germany.

Using spectral reflectance to distinguish between tracheal and oesophageal tissue: applications for airway management

Proper placement of the tracheal tube requires confirmation, and the predominant method in addition to clinical signs is the presence of end-tidal carbon dioxide. Such is the importance of confirmation that novel methods may also have a place. We previously demonstrated using ex-vivo swine tissue a unique spectral reflectance characteristic of tracheal tissue that differs from oesophageal tissue. We hypothesised that this characteristic would be present in living swine tissue and human cadavers. Reflectance spectra in the range 500-650 nm were captured using a customised fibreoptic probe, compact spectrometer and white light source from both the trachea and the oesophagus in anesthetised living swine and in human cadavers. A tracheal detection algorithm using ratio comparisons of reflectance was developed. The existence of the unique tracheal characteristic in both in-vivo swine and cadaver models was confirmed (p < 0.0001 for all comparisons between tracheal and oesophageal tissue at all target wavelengths in both species). Furthermore, our proposed tracheal detection algorithm exhibited a 100% positive predictive value in both models. This has potential utility for incorporation into airway management devices.

Optimizing Care for Trauma Patients with Obesity

Obesity is a growing epidemic that has been contributing to the increasing cost of healthcare. Its prevalence is now approximately 37%. Morbid obesity is associated with increased morbidity and mortality in trauma patients. An increased recognition of obesity as a chronic disease and a better understanding of its pathophysiology can allow for proper preparation and accommodative measures to improve resuscitation and subsequent care, thereby improving trauma outcomes. The aim of this review is to provide an overview of the scope of the problem. This review also provides evidence-based recommendations for the optimal resuscitation sequence for obese patients.

A Protocol for Helicopter In-Cabin Intubation

OBJECTIVE

The gold standard for prehospital intubation is to avoid intubating in confined spaces. For our helicopter service, this is not always realistic. Operating in a rural region with a subarctic, cold climate, our crews are frequently forced to intubate inside ambulances or in our helicopter. This article describes a protocol for in-cabin intubation and compares it with standard open space conditions.

METHODS

Fourteen prehospital physicians were randomized to solve a simplified clinical scenario during which they were to intubate a mannequin either inside the helicopter, in accordance with our in-cabin protocol, or outside on an ambulance stretcher. Participants scored intubating conditions using a visual analog scale (VAS) and the Cormack-Lehane classification. The number of intubation attempts was recorded. Three timing end points were also measured.

RESULTS

All intubations were successful on the first attempt. All participants reported an optimal glottic view of Cormack-Lehane 1 in both scenario conditions. Participants perceived in-cabin intubation to be less difficult than intubating outdoors. (VAS 1 vs. VAS 2, P = .02). We found no difference in the duration of intubation. Scene time was 53.5 seconds (P = .04) shorter in the in-cabin group. In-cabin intubation delayed the establishment of a secure airway by 63 seconds (P = .01).

CONCLUSION

Our study suggests that protocolized in-cabin intubation can be performed in a timely manner under conditions that are equal to or better than when intubating outside on a stretcher with 360-degree patient access. Although delaying the establishment of a secure airway, in-cabin intubation may reduce scene times.

Standardised data reporting from pre-hospital advanced airway management - a nominal group technique update of the Utstein-style airway template

Background

Pre-hospital advanced airway management with oxygenation and ventilation may be vital for managing critically ill or injured patients. To improve pre-hospital critical care and develop evidence-based guidelines, research on standardised high-quality data is important. We aimed to identify which airway data were most important to report today and to revise and update a previously reported Utstein-style airway management dataset.

Methods

We recruited sixteen international experts in pre-hospital airway management from Australia, United States of America, and Europe. We used a five-step modified nominal group technique to revise the dataset, and clinical study results from the original template were used to guide the process.

Results

The experts agreed on a key dataset of thirty-two operational variables with six additional system variables, organised in time, patient, airway management and system sections. Of the original variables, one remained unchanged, while nineteen were modified in name, category, definition or value. Sixteen new variables were added. The updated dataset covers risk factors for difficult intubation, checklist and standard operating procedure use, pre-oxygenation strategies, the use of drugs in airway management, airway currency training, developments in airway devices, airway management strategies, and patient safety issues not previously described.

Conclusions

Using a modified nominal group technique with international airway management experts, we have updated the Utstein-style dataset to report standardised data from pre-hospital advanced airway management. The dataset enables future airway management research to produce comparable high-quality data across emergency medical systems. We believe this approach will promote research and improve treatment strategies and outcomes for patients receiving pre-hospital advanced airway management.

Trial registration

The Regional Committee for Medical and Health Research Ethics in Western Norway exempted this study from ethical review (Reference: REK-Vest/2017/260).

Electronic supplementary material

The online version of this article (10.1186/s13049-018-0509-y) contains supplementary material, which is available to authorized users.

Airway physical examination tests for detection of difficult airway management in apparently normal adult patients

BACKGROUND

The unanticipated difficult airway is a potentially life-threatening event during anaesthesia or acute conditions. An unsuccessfully managed upper airway is associated with serious morbidity and mortality. Several bedside screening tests are used in clinical practice to identify those at high risk of difficult airway. Their accuracy and benefit however, remains unclear.

OBJECTIVES

The objective of this review was to characterize and compare the diagnostic accuracy of the Mallampati classification and other commonly used airway examination tests for assessing the physical status of the airway in adult patients with no apparent anatomical airway abnormalities. We performed this individually for each of the four descriptors of the difficult airway: difficult face mask ventilation, difficult laryngoscopy, difficult tracheal intubation, and failed intubation.

SEARCH METHODS

We searched major electronic databases including CENTRAL, MEDLINE, Embase, ISI Web of Science, CINAHL, as well as regional, subject specific, and dissertation and theses databases from inception to 16 December 2016, without language restrictions. In addition, we searched the Science Citation Index and checked the references of all the relevant studies. We also handsearched selected journals, conference proceedings, and relevant guidelines. We updated this search in March 2018, but we have not yet incorporated these results.

SELECTION CRITERIA

We considered full-text diagnostic test accuracy studies of any individual index test, or a combination of tests, against a reference standard. Participants were adults without obvious airway abnormalities, who were having laryngoscopy performed with a standard laryngoscope and the trachea intubated with a standard tracheal tube. Index tests included the Mallampati test, modified Mallampati test, Wilson risk score, thyromental distance, sternomental distance, mouth opening test, upper lip bite test, or any combination of these. The target condition was difficult airway, with one of the following reference standards: difficult face mask ventilation, difficult laryngoscopy, difficult tracheal intubation, and failed intubation.

DATA COLLECTION AND ANALYSIS

We performed screening and selection of the studies, data extraction and assessment of methodological quality (using QUADAS-2) independently and in duplicate. We designed a Microsoft Access database for data collection and used Review Manager 5 and R for data analysis. For each index test and each reference standard, we assessed sensitivity and specificity. We produced forest plots and summary receiver operating characteristic (ROC) plots to summarize the data. Where possible, we performed meta-analyses to calculate pooled estimates and compare test accuracy indirectly using bivariate models. We investigated heterogeneity and performed sensitivity analyses.

MAIN RESULTS

We included 133 (127 cohort type and 6 case-control) studies involving 844,206 participants. We evaluated a total of seven different prespecified index tests in the 133 studies, as well as 69 non-prespecified, and 32 combinations. For the prespecified index tests, we found six studies for the Mallampati test, 105 for the modified Mallampati test, six for the Wilson risk score, 52 for thyromental distance, 18 for sternomental distance, 34 for the mouth opening test, and 30 for the upper lip bite test. Difficult face mask ventilation was the reference standard in seven studies, difficult laryngoscopy in 92 studies, difficult tracheal intubation in 50 studies, and failed intubation in two studies. Across all studies, we judged the risk of bias to be variable for the different domains; we mostly observed low risk of bias for patient selection, flow and timing, and unclear risk of bias for reference standard and index test. Applicability concerns were generally low for all domains. For difficult laryngoscopy, the summary sensitivity ranged from 0.22 (95% confidence interval (CI) 0.13 to 0.33; mouth opening test) to 0.67 (95% CI 0.45 to 0.83; upper lip bite test) and the summary specificity ranged from 0.80 (95% CI 0.74 to 0.85; modified Mallampati test) to 0.95 (95% CI 0.88 to 0.98; Wilson risk score). The upper lip bite test for diagnosing difficult laryngoscopy provided the highest sensitivity compared to the other tests (P < 0.001). For difficult tracheal intubation, summary sensitivity ranged from 0.24 (95% CI 0.12 to 0.43; thyromental distance) to 0.51 (95% CI 0.40 to 0.61; modified Mallampati test) and the summary specificity ranged from 0.87 (95% CI 0.82 to 0.91; modified Mallampati test) to 0.93 (0.87 to 0.96; mouth opening test). The modified Mallampati test had the highest sensitivity for diagnosing difficult tracheal intubation compared to the other tests (P < 0.001). For difficult face mask ventilation, we could only estimate summary sensitivity (0.17, 95% CI 0.06 to 0.39) and specificity (0.90, 95% CI 0.81 to 0.95) for the modified Mallampati test.

AUTHORS' CONCLUSIONS

Bedside airway examination tests, for assessing the physical status of the airway in adults with no apparent anatomical airway abnormalities, are designed as screening tests. Screening tests are expected to have high sensitivities. We found that all investigated index tests had relatively low sensitivities with high variability. In contrast, specificities were consistently and markedly higher than sensitivities across all tests. The standard bedside airway examination tests should be interpreted with caution, as they do not appear to be good screening tests. Among the tests we examined, the upper lip bite test showed the most favourable diagnostic test accuracy properties. Given the paucity of available data, future research is needed to develop tests with high sensitivities to make them useful, and to consider their use for screening difficult face mask ventilation and failed intubation. The 27 studies in 'Studies awaiting classification' may alter the conclusions of the review, once we have assessed them.

A Randomized Comparison of In-hospital Rescuer Positions for Endotracheal Intubation in a Difficult Airway

Introduction

Emergency endotracheal intubation (ETI) is a common and critical procedure performed in both prehospital and in-hospital settings. Studies of prehospital providers have demonstrated that rescuer position influences ETI outcomes. However, studies of in-hospital rescuer position for ETI are limited. While we adhere to strict standards for the administration of ETI, we posited that perhaps requiring in-hospital rescuers to stand for ETI is an obstacle to effectiveness. Our objective was to compare in-hospital emergency medicine (EM) trainees’ performance on ETI delivered from both the seated and standing positions.

Methods

EM residents performed ETI on a difficult airway mannequin from both a seated and standing position. They were randomized to the position from which they performed ETI first. All ETIs were recorded and then scored using a modified version of the Airway Management Proficiency Checklist. Residents also rated the laryngeal view and the difficulty of the procedure. We analyzed comparisons between ETI positions with paired t-tests.

Results

Forty-two of our 49 residents (85.7%) participated. Fifteen (35.7%) were female, and all three levels of training were represented. The average number of prior ETI experiences among our subjects was 44 (standard deviation=34). All scores related to ETI performance were statistically equivalent across the two positions (performance score, number of attempts, time to intubation success, and ratings of difficulty and laryngeal view). We also observed no differences across levels of training.

Conclusion

The position of the in-hospital provider, whether seated or standing, had no effect on the provider’s ETI performance. Since environmental circumstances sometimes necessitate alternative positioning for effective ETI administration, our findings suggest that there may be value in training residents to perform ETI from both positions.

Use of ultrasound to predict difficult intubation in Chinese population by assessing the ratio of the pre-epiglottis space distance and the distance between epiglottis and vocal folds

Objective:

To investigate the accuracy of using the ratio of pre-epiglottis space distance (Pre-E) and the distance between the epiglottis and the vocal folds (Pre-E/E-VF) measured by the ultrasound to predict potential difficult airway in the Chinese population.

Design:

A prospective clinical study.

Setting:

The pre-operative assessment service clinic of Tuen Mun Hospital.

Patients:

Patients with age of 18 years or above, who were scheduled for elective surgery requiring general anesthesia with direct laryngoscopy and tracheal intubation.

Results:

A total of 113 patients with direct laryngoscopic assessment during elective operations were included. Thirty-nine (34.5%) patients had potential difficult airway which was defined as documented Cormack–Lehane classification grade 2b, 3, or 4 by the anesthetists. Measurement of the distance from the epiglottis to the anterior vocal folds (Pre-E/aVF) ratio had better inter-rater reliability and accuracy comparing to the measurements of the distances from the epiglottis to the midpoint between the vocal folds and to the posterior vocal folds. The performance of using the Pre-E/aVF ratio to predict potential difficult airway was compared with other clinical tests (the Mallampati classification, the thyromental distance and the neck circumference to thyromental distance ratio). By using the Pre-E/aVF ratio of 1, the sensitivity and specificity to predict a potential difficult airway were 79.5% and 39.2%, respectively (p = 0.044). The ultrasound assessment method had a comparable predictive value as the Mallampati classification (the area under the receiver operator characteristic curves 0.648 vs 0.687). The negative likelihood ratio of the ultrasound assessment method was the lowest among all the other airway assessment methods.

Conclusion:

The ultrasound airway assessment method could serve as a non-invasive test and supplement the currently used clinical assessment methods. A lower cut-off point of the Pre-E/E-VF ratio should be used in the Chinese population.

Anesthetic Considerations in Patients Undergoing Bariatric Surgery: A Review Article

Context

This article discusses the anesthetic considerations in patients undergoing bariatric surgery in the preoperative, intraoperative, and postoperative phases of surgery.

Evidence Acquisition

This review includes studies involving obese patients undergoing bariatric surgery. Searches have been conducted in PubMed, MEDLINE, EMBASE, Google Scholar, Scopus, and Cochrane Database of Systematic Review using the terms obese, obesity, bariatric, anesthesia, perioperative, preoperative, perioperative, postoperative, and their combinations.

Results

Obesity is a major worldwide health problem associated with many comorbidities. Bariatric surgery has been proposed as the best alternative treatment for extreme obese patients when all other therapeutic options have failed.

Conclusions

Anesthetists must completely assess the patients before the surgery to identify anesthesia- related potential risk factors and prepare for management during the surgery.

Novel Airway Training Tool that Simulates Vomiting: Suction-Assisted Laryngoscopy Assisted Decontamination (SALAD) System

INTRODUCTION

We present a novel airway simulation tool that recreates the dynamic challenges associated with emergency airways. The Suction-Assisted Laryngoscopy Assisted Decontamination (SALAD) simulation system trains providers to use suction to manage emesis and bleeding complicating intubation.

METHODS

We modified a standard difficult-airway mannequin head (Nasco, Ft. Atkinson, WI) with hardware-store equipment to enable simulation of vomiting or hemorrhage during intubation. A pre- and post-survey was used to assess the effectiveness of the SALAD simulator. We used a 1-5 Likert scale to assess confidence in managing the airway of a vomiting patient and comfort with suction techniques before and after the training exercise.

RESULTS

Forty learners participated in the simulation, including emergency physicians, anesthesiologists, paramedics, respiratory therapists, and registered nurses. The average Likert score of confidence in managing the airway of a vomiting or hemorrhaging patient pre-session was 3.10±0.49, and post-session 4.13±0.22. The average score of self-perceived skill with suction techniques in the airway scenario pre-session was 3.30±0.43, and post-session 4.03±0.26. The average score for usefulness of the session was 4.68±0.15, and the score for realism of the simulator was 4.65±0.17.

CONCLUSION

A training session with the SALAD simulator improved trainee's confidence in managing the airway of a vomiting or hemorrhaging patient. The SALAD simulation system recreates the dynamic challenges associated with emergency airways and holds promise as an airway training tool.

Comparison of five 2nd-generation supraglottic airway devices for airway management performed by novice military operators

OBJECTIVES

Five different second-generation supraglottic airway devices, ProSeal LMA, Supreme LMA, i-gel, SLIPA, and Laryngeal Tube Suction-D, were studied. Operators were inexperienced users with a military background, combat lifesavers, nurses, and physicians.

METHODS

This was a prospective, randomized, single-blinded study. Devices were inserted in the operating room in low light conditions after induction of general anesthesia. Primary outcome was successful insertion on the first attempt while secondary aims were insertion time, number of attempts, oropharyngeal seal pressure, ease of insertion, fibre optic position of device, efficacy of ventilation, and intraoperative trauma or regurgitation of gastric contents.

RESULTS

In total, 505 patients were studied. First-attempt insertion success rate was higher in the Supreme LMA (96%), i-gel (87.9%), and ProSeal LMA (85.9%) groups than in the Laryngeal Tube Suction-D (80.6%) and SLIPA (69.4%) groups. Insertion time was shortest in the Supreme LMA (70.4 ± 32.5 s) and i-gel (74.4 ± 41.1 s) groups (p < 0.001). Oropharyngeal seal pressures were higher in the Laryngeal Tube Suction-D and ProSeal LMA groups than in other three devices.

CONCLUSIONS

Most study parameters for the Supreme LMA and i-gel were found to be superior to the other three tested supraglottic airway devices when inserted by novice military operators.

Airway management by physician-staffed Helicopter Emergency Medical Services - a prospective, multicentre, observational study of 2,327 patients

Background

Despite numerous studies on prehospital airway management, results are difficult to compare due to inconsistent or heterogeneous data. The objective of this study was to assess advanced airway management from international physician-staffed helicopter emergency medical services.

Methods

We collected airway data from 21 helicopter emergency medical services in Australia, England, Finland, Hungary, Norway and Switzerland over a 12-month period. A uniform Utstein-style airway template was used for collecting data.

Results

The participating services attended 14,703 patients on primary missions during the study period, and 2,327 (16 %) required advanced prehospital airway interventions. Of these, tracheal intubation was attempted in 92 % of the cases. The rest were managed with supraglottic airway devices (5 %), bag-valve-mask ventilation (2 %) or continuous positive airway pressure (0.2 %). Intubation failure rates were 14.5 % (first-attempt) and 1.2 % (overall). Cardiac arrest patients showed significantly higher first-attempt intubation failure rates (odds ratio: 2.0; 95 % CI: 1.5-2.6; p < 0.001) compared to non-cardiac arrest patients. Complications were recorded in 13 %, with recognised oesophageal intubation being the most frequent (25 % of all patients with complications). For non-cardiac arrest patients, important risk predictors for first-attempt failure were patient age (a non-linear association) and administration of sedatives (reduced failure risk). The patient’s sex, provider’s intubation experience, trauma type (patient category), indication for airway intervention and use of neuromuscular blocking agents were not risk factors for first-attempt intubation failure.

Conclusions

Advanced airway management in physician-staffed prehospital services was performed frequently, with high intubation success rates and low complication rates overall. However, cardiac arrest patients showed significantly higher first-attempt failure rates compared to non-cardiac arrest patients. All failed intubations were handled successfully with a rescue device or surgical airway.

Trial registration

Study registration: www.clinicaltrials.govNCT01502111. Registered 22 December 2011.

Comparison of five methods in predicting difficult laryngoscopy: Neck circumference, neck circumference to thyromental distance ratio, the ratio of height to thyromental distance, upper lip bite test and Mallampati test

Background:

Preoperative airway assessment tests have been presented to help in anticipating a difficult airway. We conducted this study to compare five methods in prediction of difficult laryngoscopy: Neck circumference (NC), NC to thyromental distance ratio (NC/TMD), the ratio of height to thyromental distance (RHTMD), upper lip bite test (ULBT) and Mallampati test (MMT). These five methods are the most commonly used ones and have different powers for it. It was not clear which of these methods predicts difficult laryngoscopy better.

Materials and Methods:

Six hundred consecutive patients participated in this study. NC, NC/TMD and RHTMD were measured, and ULBT and MMT were performed and recorded. The laryngoscopy view was graded according to Cormack and Lehane's scale (CLS) and difficult laryngoscopy was defined as CLS grades 3 and 4. Accuracy of tests in predicting difficult laryngoscopy was assessed using the area under a receiver-operating characteristic curve.

Results:

The area under the curve in ULBT and RHTMD were significantly larger than that in TMD, NC and MMT. No statistically significant differences were noted between TMD, NC and MMT (all P > 0.05) (ULBT = RHTMD > NC/TMD > TMD = NC = MMT). RHTMD (>22.7 cm) exhibited the highest sensitivity (sensitivity = 64.77, 95% confidence interval [CI]: 53.9–74.7) and the most specific test was ULBT (specificity = 99.41%, 95% CI: 98.3–99.9).

Conclusion:

RHTMD and ULBT as simple preoperative bedside tests have a higher level of accuracy compared to NC/TMD, TMD, NC, MMT in predicting a difficult airway.

Prehospital use of cervical collars in trauma patients: a critical review

The cervical collar has been routinely used for trauma patients for more than 30 years and is a hallmark of state-of-the-art prehospital trauma care. However, the existing evidence for this practice is limited: Randomized, controlled trials are largely missing, and there are uncertain effects on mortality, neurological injury, and spinal stability. Even more concerning, there is a growing body of evidence and opinion against the use of collars. It has been argued that collars cause more harm than good, and that we should simply stop using them. In this critical review, we discuss the pros and cons of collar use in trauma patients and reflect on how we can move our clinical practice forward. Conclusively, we propose a safe, effective strategy for prehospital spinal immobilization that does not include routine use of collars.

Complex Interaction between Obesity and Trauma

Trauma and obesity are large-scale epidemics that can be associated with significant morbidity and mortality. In few studies, it has noted that there is the ‘obesity paradox’ (obesity has been found to be protective against mortality) due to certain causes, i.e. heart failure or cardiovascular disease. Subcutaneous fat can show great variability between individuals and increased subcutaneous fat may be protective against injuries by cushioning the internal abdominal organs against injurious forces in road traffic accidents. Many factors including the body fat distribution, body shape, and center of gravity may play an important role in the different injury patterns and severity of injury between men and women. A better understanding of how obesity influences trauma related injuries not only will help to improve the outcome but also foster the development of interventions to address the most salient and modifiable risk factors to reduce obesity related morbidity and mortality. In present article, we review the relevant literature with special considerations to understand the interactions of obesity and trauma with their impact on patient management and outcomes.

How to cite this article

Agrawal A. Complex Interaction between Obesity and Trauma. Panam J Trauma Crit Care Emerg Surg 2014;3(3):109-113.

Laryngeal tube use in out-of-hospital cardiac arrest by paramedics in Norway

Background

Although there are numerous supraglottic airway alternatives to endotracheal intubation, it remains unclear which airway technique is optimal for use in prehospital cardiac arrests. We evaluated the use of the laryngeal tube (LT) as an airway management tool among adult out-of-hospital cardiac arrest (OHCA) patients treated by our ambulance services in the Haukeland and Innlandet hospital districts.

Methods

Post-resuscitation forms and data concerning airway management in 347 adult OHCA victims were retrospectively assessed with regard to LT insertion success rates, ease and speed of insertion and insertion-related problems.

Results

A total of 402 insertions were performed on 347 OHCA patients. Overall, LT insertion was successful in 85.3% of the patients, with a 74.4% first-attempt success rate. In the minority of patients (n = 46, 13.3%), the LT insertion time exceeded 30 seconds. Insertion-related problems were recorded in 52.7% of the patients. Lack of respiratory sounds on auscultation (n = 100, 28.8%), problematic initial tube positioning (n = 85, 24.5%), air leakage (n = 61, 17.6%), vomitus/aspiration (n = 44, 12.7%), and tube dislocation (n = 17, 4.9%) were the most common problems reported. Insertion difficulty was graded and documented for 95.4% of the patients, with the majority of insertions assessed as being “Easy” (62.5%) or “Intermediate” (24.8%). Only 8.1% of the insertions were considered to be “Difficult”.

Conclusions

We found a high number of insertion related problems, indicating that supraglottic airway devices offering promising results in manikin studies may be less reliable in real-life resuscitations. Still, we consider the laryngeal tube to be an important alternative for airway management in prehospital cardiac arrest victims.

Analysis of prehospital endotracheal intubation performed by emergency physicians: retrospective survey of a single emergency medical center in Japan

OBJECTIVES

Advanced airway management in the prehospital setting is a serious issue in Japan because emergency medical technicians are not authorized to perform such management, whereas physicians-who are authorized to perform advanced airway management-do not usually engage in prehospital emergency medical activity. The purpose of this investigation was to investigate the success rate for endotracheal intubation (ETI) procedures and other methods of airway management employed by physicians in the prehospital setting in a single institution, as well as to examine the risk factors associated with difficult or failed endotracheal intubation (D/F ETI).

METHODS

We performed a retrospective survey of patients treated in the prehospital setting by emergency physicians of the Hyogo Emergency Medical Center from 2004 to 2011. Patients were divided into two groups: a cardiopulmonary arrest (CPA) group and a non-CPA group. Data on cases of D/F ETI were obtained, and risk factors for these two groups were identified using univariate and statistical analysis.

RESULTS

During the investigation period, ETI was attempted in the prehospital setting on 742 eligible patients; in 30 (4.04 %) of these cases, the attempts at ETI proved difficult or failed. Of those 30 patients, 13 patients received a surgical airway (attempts to provide a surgical airway failed in two patients), a blind ETI was performed in four, a video-assisted airway device was used in another four, and esophageal intubation was performed in four patients. Bag-valve ventilation alone was performed in one patient. The incidence of D/F ETI was higher in the non-CPA group than in the CPA group (6.27 vs. 2.63 %: p < 0.05). Facial or neck injury was a risk factor for D/F ETI in the prehospital setting in the CPA group (odds ratio 7.855; 95 % CI 1.754-36.293: p = 0.042). On the other hand, no risk factors for D/F ETI in the prehospital setting in the non-CPA group were identified.

CONCLUSION

The success rate for ETI performed by physicians in the prehospital setting at a single emergency medical center was high, and the incidence of D/F ETI was 4.31 %. The success rate for ETI in the CPA group was greater than that in the non-CPA group.

[Emergency anesthesia, airway management and ventilation in major trauma. Background and key messages of the interdisciplinary S3 guidelines for major trauma patients]

Patients with multiple trauma presenting with apnea or a gasping breathing pattern (respiratory rate  < 6/min) require prehospital endotracheal intubation (ETI) and ventilation. Additional indications are hypoxia (S(p)O(2)  < 90% despite oxygen insufflation and after exclusion of tension pneumothorax), severe traumatic brain injury [Glasgow Coma Scale (GCS)  < 9], trauma-associated hemodynamic instability [systolic blood pressure (SBP)  < 90 mmHg] and severe chest trauma with respiratory insufficiency (respiratory rate  > 29/min). The induction of anesthesia after preoxygenation is conducted as rapid sequence induction (analgesic, hypnotic drug, neuromuscular blocking agent). With the availability of ketamine as a viable alternative, the use of etomidate is not encouraged due to its side effects on adrenal function. An electrocardiogram (ECG), blood pressure measurement and pulse oximetry are needed to monitor the emergency anesthesia and the secured airway. Capnography is absolutely mandatory to confirm correct placement of the endotracheal tube and to monitor tube dislocations as well as ventilation in the prehospital and hospital setting. Because airway management is often complicated in trauma patients, alternative devices need to be available preclinical and a fiber-optic endoscope should be available within the hospital. Use of these alternative measures for airway management and ventilation should be considered at the latest after a maximum of three unsuccessful endotracheal intubation attempts. Emergency medical service (EMS) physicians should to be trained in emergency anesthesia, ETI and alternative methods of airway management on a regular basis. Within hospitals ETI, emergency anesthesia and ventilation are to be conducted by trained and experienced anesthesiologists. When a difficult airway or induction of anesthesia is expected, endotracheal intubation should be supervised or conducted by an anesthesiologist. Normoventilation should be the goal of mechanical ventilation. After arrival in the resuscitation room the ventilation will be controlled and guided with the help of arterial blood gas analyses. After temporary removal of a cervical collar, the cervical spine needs to be immobilized by means of manual in-line stabilization when securing the airway.

[Emergency anesthesia, airway management and ventilation in major trauma. Background and key messages of the interdisciplinary S3 guidelines for major trauma patients]

Patients with multiple trauma presenting with apnea or a gasping breathing pattern (respiratory rate <6/min) require prehospital endotracheal intubation (ETI) and ventilation. Additional indications are hypoxia (S(p)O(2)<90% despite oxygen insufflation and after exclusion of tension pneumothorax), severe traumatic brain injury [Glasgow Coma Scale (GCS)<9], trauma-associated hemodynamic instability [systolic blood pressure (SBP)<90 mmHg] and severe chest trauma with respiratory insufficiency (respiratory rate >29/min). The induction of anesthesia after preoxygenation is conducted as rapid sequence induction (analgesic, hypnotic drug, neuromuscular blocking agent). With the availability of ketamine as a viable alternative, the use of etomidate is not encouraged due to its side effects on adrenal function. An electrocardiogram (ECG), blood pressure measurement and pulse oximetry are needed to monitor the emergency anesthesia and the secured airway. Capnography is absolutely mandatory to confirm correct placement of the endotracheal tube and to monitor tube dislocations as well as ventilation and oxygenation in the prehospital and hospital setting. Because airway management is often complicated in trauma patients, alternative devices and a fiber-optic endoscope need to be available within the hospital. Use of these alternative measures for airway management and ventilation should be considered at the latest after a maximum of three unsuccessful intubation attempts. Emergency medical service (EMS) physicians should to be trained in emergency anesthesia, ETI and alternative methods of airway management on a regular basis. Within hospitals ETI, emergency anesthesia and ventilation are to be conducted by trained and experienced anesthesiologists. When a difficult airway or induction of anesthesia is expected, endotracheal intubation should be supervised or conducted by an anesthesiologist. Normoventilation should be the goal of mechanical ventilation. After arrival in the resuscitation room the ventilation will be controlled and guided with the help of arterial blood gas analyses. After temporary removal of a cervical collar, the cervical spine needs to be immobilized by means of manual in-line stabilization when securing the airway.