Prehospital endotracheal intubation: rationale for training emergency medical personnel

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.

Development of a Hand Motion-based Assessment System for Endotracheal Intubation Training

Endotracheal intubation (ETI) is a procedure to manage and secure an unconscious patient's airway. It is one of the most critical skills in emergency or intensive care. Regular training and practice are required for medical providers to maintain proficiency. Currently, ETI training is assessed by human supervisors who may make inconsistent assessments. This study aims at developing an automated assessment system that analyzes ETI skills and classifies a trainee into an experienced or a novice immediately after training. To make the system more available and affordable, we investigate the feasibility of utilizing only hand motion features as determining factors of ETI proficiency. To this end, we extract 18 features from hand motion in time and frequency domains, and also 12 force features for comparison. Subsequently, feature selection algorithms are applied to identify an ideal feature set for developing classification models. Experimental results show that an artificial neural network (ANN) classifier with five hand motion features selected by a correlation-based algorithm achieves the highest accuracy of 91.17% while an ANN with five force features has only 80.06%. This study corroborates that a simple assessment system based on a small number of hand motion features can be effective in assisting ETI training.

Mechanical Ventilation of Severe Traumatic Brain Injury Patients in the Prehospital Setting

OBJECTIVE

Suboptimal ventilation may impact outcomes in patients with traumatic brain injury (TBI). This study compares the incidence of eucapnia between manually and mechanically ventilated patients with severe TBI during helicopter transport.

METHODS

This retrospective chart review included consecutive intubated adults with severe TBI (Glasgow Coma Scale score < 9) transported by helicopter from the scene of injury to a level 1 trauma center between 2009 and 2015. The primary outcome was the first venous partial pressure of carbon dioxide obtained in the emergency department. Hypocapnia, eucapnia, and hypercapnia were defined based on the normal range for the testing instrument. The Fisher exact test was used to compare groups.

RESULTS

Of 1,070 trauma patients intubated and transported, 93 met the inclusion criteria with full data. The mean age was 43 years, 81 of 93 were white, and 70 of 93 were men. The mean Injury Severity Score was 29, and 26 of 93 were mechanically ventilated. Hypocapnia occurred in 4 of 93 and hypercapnia in 56 of 93. There was no difference in the rate of eucapnia in manually ventilated compared with mechanically ventilated patients (36% vs. 35%, P = 1.00).

CONCLUSION

Eucapnia at emergency department arrival occurred in 36% of patients and was unaffected by whether ventilation was manually or mechanically controlled. Few patients were hypocapnic, indicating a low incidence of hyperventilation during helicopter transport.

Comparison of the Force Required for Dislodgement Between Secured and Unsecured Airways

INTRODUCTION

Airway device placement and maintenance are of utmost importance when managing critically ill patients. The best method to secure airway devices is currently unknown.

STUDY OBJECTIVE

We sought to determine the force required to dislodge 4 types of airways with and without airway securing devices.

METHODS

We performed a prospective study using 4 commonly used airway devices (endotracheal tube [ETT], laryngeal mask airway [LMA], King laryngeal tube [King], and iGel) performed on 5 different mannequin models. All devices were removed twice per mannequin in random order, once unsecured and once secured as per manufacturers' recommendations; Thomas Tube Holder (Laerdal, Stavanger, Norway) for ETT, LMA, and King; custom tube holder for iGel. A digital force measuring device was attached to the exposed end of the airway device and gradually pulled vertically and perpendicular to the mannequin until the tube had been dislodged, defined as at least 4 cm of movement. Dislodgement force was reported as the maximum force recorded during dislodgement. We compared the relative difference in the secured and unsecured force for each device and between devices using a random-effects regression model accounting for variability in the manikins.

RESULTS

The median dislodgment forces (interquartile range [IQR]) in pounds for each secured device were: ETT 13.3 (11.6, 14.1), LMA 16.6 (13.9, 18.3), King 21.7 (16.9, 25.1), and iGel 8 (6.8, 8.3). The median dislodgement forces for each unsecured device were: ETT 4.5 (4.3, 5), LMA 8.4 (6.8, 10.7), King 10.6 (8.2, 11.5), and iGel 3.9 (3.2, 4.2). The relative difference in dislodgement forces (95% confidence intervals) were higher for each device when secured: ETT 8.6 (6.2 to 11), LMA 8.8 (4.6 to 13), King 12.1 (7.2 to 16.6), iGel 4 (1.1 to 6.9). When compared to secured ETT, the King required greater dislodgement force (relative difference 8.6 [4.5-12.7]). The secured iGel required less force than the secured ETT (relative difference -4.8 [-8.9 to -0.8]).

CONCLUSION

Compared with a secured device, an unsecured airway device requires only half the force to cause airway dislodgement. The secured King had the highest dislodgement force relative to the other studied devices.

A systematic review and meta-analysis comparing mortality in pre-hospital tracheal intubation to emergency department intubation in trauma patients

Background

Pre-hospital endotracheal intubation is frequently used for trauma patients in many emergency medical systems. Despite a wide range of publications in the field, it is debated whether the intervention is associated with a favourable outcome, when compared to more conservative airway measures.

Methods

A systematic literature search was conducted to identify interventional and observational studies where the mortality rates of adult trauma patients undergoing pre-hospital endotracheal intubation were compared to those undergoing emergency department intubation.

Results

Twenty-one studies examining 35,838 patients were included. The median mortality rate in patients undergoing pre-hospital intubation was 48% (range 8–94%), compared to 29% (range 6–67%) in patients undergoing intubation in the emergency department. Odds ratios were in favour of emergency department intubation both in crude and adjusted mortality, with 2.56 (95% CI: 2.06, 3.18) and 2.59 (95% CI: 1.97, 3.39), respectively. The overall quality of evidence is very low. Twelve of the twenty-one studies found a significantly higher mortality rate after pre-hospital intubation, seven found no significant differences, one found a positive effect, and for one study an analysis of the mortality rate was beyond the scope of the article.

Conclusions

The rationale for wide and unspecific indications for pre-hospital intubation seems to lack support in the literature, despite several publications involving a relatively large number of patients. Pre-hospital intubation is a complex intervention where guidelines and research findings should be approached cautiously. The association between pre-hospital intubation and a higher mortality rate does not necessarily contradict the importance of the intervention, but it does call for a thorough investigation by clinicians and researchers into possible causes for this finding.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1787-x) contains supplementary material, which is available to authorized users.

Unrecognized failed airway management using a supraglottic airway device

BACKGROUND

911 Emergency Medical Services (EMS) systems utilize supraglottic devices for either primary advanced airway management, or for airway rescue following failed attempts at direct laryngoscopy endotracheal intubation. There is, however, limited data on objective confirmation of supraglottic airway placement in the prehospital environment. Furthermore, the ability of EMS field providers to recognize a misplaced airway is unknown.

METHODS

Retrospective review of patients who underwent airway management using the King LTS-D supraglottic airway in a large urban EMS system, between 3/1/15-9/30/2015. Subjective success was defined as documentation of successful airway placement by the EMS provider. Objective success was confirmed by review of waveform capnography, with the presence of a 4-phase waveform greater than 5mmHg. Sensitivity and specificity of the field provider's assessment of success were then calculated.

RESULTS

A total of 344 supraglottic airway attempts were reviewed. No patients met obvious death criteria. 269 attempts (85.1%) met criteria for both subjective and objective success. 19 attempts (5.6%) were recognized failures by the EMS provider. 47 (13.8%) airways were misplaced but unrecognized by the EMS provider. 4 attempts (1.2%) were correctly placed but misidentified as failures, leading to the unnecessary removal and replacement of the airway. Sensitivity of the provider's assessment was 98.5%; specificity was 28.7%.

CONCLUSION

The use of supraglottic airway devices results in unrecognized failed placement. Appropriate utilization and review of waveform capnography may remedy a potential blind-spot in patient safety, and systemic monitoring/feedback processes may therefore be used to prevent unrecognized misplaced airways.

Derivation and Validation of The Prehospital Difficult Airway IdentificationTool (PreDAIT): A Predictive Model for Difficult Intubation

Introduction

Endotracheal intubation (ETI) in the prehospital setting poses unique challenges where multiple ETI attempts are associated with adverse patient outcomes. Early identification of difficult ETI cases will allow providers to tailor airway-management efforts to minimize complications associated with ETI. We sought to derive and validate a prehospital difficult airway identification tool based on predictors of difficult ETI in other settings.

Methods

We prospectively collected patient and airway data on all airway attempts from 16 Advanced Life Support (ALS) ground emergency medical services (EMS) agencies from January 2011 to October 2014. Cases that required more than two ETI attempts and cases where an alternative airway strategy (e.g. supraglottic airway) was employed after one unsuccessful ETI attempt were categorized as “difficult.” We used a random allocation sequence to split the data into derivation and validation subsets. Using backward elimination, factors with a p<0.1 were included in the multivariable regression for the derivation cohort and then tested in the validation cohort. We used this model to determine the area under the curve (AUC), and the sensitivity and specificity for each cut point in both the derivation and validation cohorts.

Results

We collected data on 1,102 cases with 568 in the derivation set (155 difficult cases; 27%) and 534 in the validation set (135 difficult cases; 25%). Of the collected variables, five factors were predictive of difficult ETI in the derivation model (adjusted odds ratio, 95% confidence interval [CI]): Glasgow coma score [GCS] >3 (2.15, 1.19–3.88), limited neck movement (2.24, 1.28–3.93), trismus/jaw clenched (2.24, 1.09–4.6), inability to palpate the landmarks of the neck (5.92, 2.77–12.66), and fluid in the airway such as blood or emesis (2.25, 1.51–3.36). This was the most parsimonious model and exhibited good fit (Hosmer-Lemeshow test p = 0.167) with an AUC of 0.68 (95% CI [0.64–0.73]). When applied to the validation set, the model had an AUC of 0.63 (0.58–0.68) with high specificity for identifying difficult ETI if ≥2 factors were present (87.7% (95% CI [84.1–90.8])).

Conclusion

We have developed a simple tool using five factors that may aid prehospital providers in the identification of difficult ETI.

Evolving Challenges in Prehospital Trauma Services: Current Issues and Suggested Evaluation Tools

For the past two decades, prehospital trauma care has been addressed almost generically in terms of the related approaches to epidemiology, research, and management. However, evolving directions in research have helped emergency medical services (EMS) practitioners to delineate more focused treatment strategies according to the mechanism of injury, anatomic involvement, and the patient's clinical condition. Recent studies in the areas of trauma-associated circulatory arrest, severe blunt head injury, and post-traumatic hemorrhage following penetrating truncal injury suggest that current standard approaches to patient care should be reconsidered. In turn, this need for re-examination of trauma management strategies calls for the development of appropriate evaluation tools within EMS systems. Proper research design is dependent upon several key issues including: 1) the type of study (system study versus examination of a specific intervention); 2), the population under study; 3) physiological and anatomical scoring method; 4) prospective definitions of interventions and meaningful outcome variables (both morbidity and mortality; 5) relative outcome compared to known standards; and 6) prospective determination of statistical requirements.

Paediatric prehospital trauma care

Trauma is the major cause of avoidable death in children in the UK. For many injured children, their initial contact with medical care is with the ambulance service. The main focus of this article is paediatric prehospital trauma care in the UK. It identifies its strengths and highlights areas where improvements are needed. For comparison’s sake, mention is also made of the prehospital care for traumatized children in the USA, which is part of a system termed ‘Emergency Medical Services for Children’ (EMSC). Training and equipment issues, field triage and the ABC of advanced life support of injured children is examined.

Future directions for this important aspect of emergency care are discussed, as are issues relevant to research and audit in this area.

Prehospital endotracheal intubation: elemental or detrimental?

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2015 and co-published as a series in Critical Care. Other articles in the series can be found online at http://ccforum.com/series/annualupdate2015. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Biomechanical evaluation of the phases during simulated endotracheal intubation (ETI): pilot study on the effect of different laryngoscopes

Endotracheal Intubation (ETI) is a common airway procedure used to connect the larynx and the lungs through a windpipe in patients under emergency situations. The process is carried out by a laryngoscope inserted into the mouth, used to help doctors in visualizing the glottis and inserting the tube. Currently, very few studies on objective evaluation of the biomechanics of the doctors during the procedure have been done. Additionally, these studies have been concentrated only on the overall performance analysis, without any segmentation, with a consequent loss of important information. In this paper, the authors present a preliminary study on a methodology to objectively evaluate and segment the biomechanical performance of doctors during the ETI, using surface electromyography and inertial measurement units. In particular, the validation has been performed by comparing three kinds of laryngoscopes involving an expert doctor. Finally, results are presented and commented.

A Prospective Evaluation of Prehospital Patient Assessment by Direct In-field Observation: Failure of ALS Personnel to Measure Vital Signs

We prospectively evaluated the frequency with which advanced life support (ALS) personnel fail to attempt to measure blood pressure (BP) and/or pulse (P) during prehospital patient assessment. A single in-field observer rode on ALS rescue vehicles from 20 Emergency Medical Services (EMS) agencies throughout Arizona during a one-year study (1/89–12/89). Data were collected from urban, suburban, and rural systems. Statistical evaluation was performed by Chi Square analysis with p <0.05 considered significant.

Among 227 patient encounters, BP and/or P measurements were omitted in 84 cases (37.0%). BP and/or P were omitted in 50.0% of children (age <18 years) compared to 26.5% of adults (p=0.023). Among patients who were transported to a hospital, 19.4% had BP omitted compared to 49.1% of those not transported (p=0.00003). Seven of 58 patients in whom TVs were attempted (12.1 %) had BP omitted compared to 54 of 169 patients without IV attempts (32.0%, p=0.0055). Blood Pressure was omitted in 21.9% of patients transported Code 3 and in 24.2% of patients with Glasgow Coma Scale ≤13. Omission of BP occurred more frequently in non-urban agencies (33.9%) than in urban ones (20.0%, p=0.027).

In a statewide evaluation of prehospital patient assessment, failure to measure vital signs (VS) occurred on a frequent basis. Our data indicate that a concerning lack of attention to the most basic details of patient assessment is common. It is possible that failure to measure VS might even happen more frequently during routine patient encounters without an observer present. Medical control physicians must emphasize to EMS personnel the paramount importance of careful assessment to ensure optimal patient care.

Analysis of Prehospital Scene Time and Survival from Out-of-Hospital, Non-Traumatic, Cardiac Arrest

The purpose of this study was to determine whether shorter prehospital scene time (ST) is associated with an increased survival rate in non-traumatic, out-of-hospital, cardiac arrest (CA) in a medium-sized, metropolitan EMS system. Information was retrieved for all adult victims (age ≥18 years) of CA treated and transported by a metropolitan fire department over a 16month period (6/87–9/88). Data were retrieved from the fire department's database, hospital records, and death certificates. Statistical analysis of continuous variables was performed using the two-tailed, Student's t-test and non-parametric evaluations were performed by square analysis with p<0.05 considered significant. Two hundred ninety-eight cases were recorded of which 293 patients (98.3%) had documented ST (study group). Seventy-nine patients (27.0%) had ST <12 minutes, while 214 (73.0%) had ST≥12 minutes. Patients with ST <12 minutes were more likely to have return of spontaneous circulation in the field (26.6% vs. 15.9%, p<0.05) and also were more likely to survive than were patients with ST ≥12 minutes (13.9% vs. 6.5%, p<0.05). Mean ST for survivors was significantly less than for non-survivors (12.8 vs. 15.3 min., p<0.05).

We conclude that, in our system, adult victims of CA with ST <12 minutes are more likely to survive than are patients with longer ST. In addition, the mean ST for survivors is shorter than for non-survivors. It remains unclear whether shorter ST actually has an impact on survival or is merely a reflection of a sub-group with rapid resuscitation and consequently a higher likelihood of survival. Future investigations are needed to determine whether shorter ST actually impacts the likelihood of survival from CA.

Variables associated with successful intubation attempts using video laryngoscopy: a preliminary report in a helicopter emergency medical service

BACKGROUND

Multiple studies have demonstrated varying rates of successful endotracheal intubation (ETI). Until the application of video laryngoscopy, little information regarding prehospital intubation could be analyzed objectively by individuals other than the provider performing the ETI.

OBJECTIVE

To evaluate the association of variables recorded during video laryngoscopy and successful ETI attempts, defined as placing the endotracheal tube in the trachea.

METHODS

We retrospectively reviewed intubations performed by a single helicopter emergency medical service (HEMS) using a video larygoscope from March 1, 2010, to October 1, 2010. All videos were de-identified and analyzed by a single researcher. Time intervals (e.g., attempt time) and intubation process variables (e.g., Cormack-Lehane [C-L] view) were abstracted from all videos. Time intervals were begun when the laryngoscope blade passed the lips and entered the oral cavity (entry). We describe variables using means and standard deviations (continuous), medians with interquartile ranges (ordinal), and percentages with 95% confidence intervals (categorical). We then looked at univariate associations between these variables and ETI success using logistic regression.

RESULTS

We recorded 116 intubations during the study period. Twenty-nine recordings were either incomplete (n = 26) or of insufficient quality for analysis (n = 3). The remaining 87 videos represented 87 different patients with a total of 102 attempts at laryngoscopy. Thirty-six providers performed 64 cases, with the majority of providers (n = 21) performing only one intubation. The first-pass success rate in this series was 76% (n = 66), with 98% success within three attempts. Successful ETI attempts had lower entry-to-percentage of glottic opening (POGO) times (16.6 sec vs. 32.1 sec, p = 0.013), entry-to-first view of the endotracheal tube or entry-to-tube times (17.6 sec vs. 27.4 sec, p = 0.04), higher POGO scores (76 vs. 39, p < 0.001), and a lower C-L view (one vs. three, p < 0.001). Recognized esophageal intubation was more likely to occur during unsuccessful ETI attempts (43% vs. 8%, p < 0.001).

CONCLUSION

Video laryngoscopy can measure multiple components of ETI performance. Successful ETI attempts have significantly shorter entry-to-POGO times and entry-to-tube times, obtain better views of the glottic opening (POGO and C-L view), and have a lower incidence of recognized esophageal intubation.

Should trauma patients with a Glasgow Coma Scale score of 3 be intubated prior to hospital arrival?

INTRODUCTION

Previous studies of heterogeneous populations (Glasgow Coma Scale (GCS) scores<9) suggest that endotracheal intubation of trauma patients prior to hospital arrival (i.e., prehospital intubated) is associated with an increased mortality compared to those patients not intubated in the prehospital setting. Deeply comatose patients (GCS=3) represent a unique population of severely traumatized patients and may benefit from intubation in the prehospital setting. The objective of this study was to compare mortality rates of severely comatose patients (scene GCS=3) with prehospital endotracheal intubation to those intubated at the hospital.

METHODS

Using the National Trauma Data Bank (V. 6.2), the following variables were analyzed retrospectively: (1) age; (2) injury type (blunt or penetrating); (3) Injury Severity Score (ISS); (4) scene GCS=3 (scored prior to intubation/without sedation); (5) emergency department GCS score; (6) arrival emergency department intubation status; (7) first systolic blood pressure in the emergency department (>0); (8) discharge status (alive or dead); (9) Abbreviated Injury Scale Score (AIS); and (10) AIS body region.

RESULTS

Of the 10,948 patients analyzed, 23% (2,491/10,948) were endotracheally intubated in a prehospital setting. Mortality rate for those hospital intubated was 35% vs. 62% for those with prehospital intubation (p<0.0001); mean ISS scores 24.2±16.0 vs. 31.6±16.2, respectively (p<0.0001). Using logistic regression, controlling for first systolic blood pressure, ISS, emergency department GCS, age, and type of trauma, those with prehospital intubation were more likely to die (OR=1.9, 95% CI=1.7-2.2). For patients with only head AIS scores (no other body region injury, n=1,504), logistic regression (controlling for all other variables) indicated that those with prehospital intubation were still more likely to die (OR=2.0. 95% CI=1.4-2.9).

CONCLUSIONS

Prehospital endotracheal intubation is associated with an increased mortality in completely comatose trauma patients (GCS = 3). Although the exact reasons for this remain unclear, these results support other studies and suggest the need for future research and re-appraisal of current policies for prehospital intubation in these severely traumatized patients.

Advanced medical life support procedures in vitally compromised children by a helicopter emergency medical service

Background

To determine the advanced life support procedures provided by an Emergency Medical Service (EMS) and a Helicopter Emergency Medical Service (HEMS) for vitally compromised children. Incidence and success rate of several procedures were studied, with a distinction made between procedures restricted to the HEMS-physician and procedures for which the HEMS is more experienced than the EMS.

Methods

Prospective study of a consecutive group of children examined and treated by the HEMS of the eastern region of the Netherlands. Data regarding type of emergency, physiological parameters, NACA scores, treatment, and 24-hour survival were collected and subsequently analysed.

Results

Of the 558 children examined and treated by the HEMS on scene, 79% had a NACA score of IV-VII. 65% of the children had one or more advanced life support procedures restricted to the HEMS and 78% of the children had one or more procedures for which the HEMS is more experienced than the EMS. The HEMS intubated 38% of all children, and 23% of the children intubated and ventilated by the EMS needed emergency correction because of potentially lethal complications. The HEMS provided the greater part of intraosseous access, as the EMS paramedics almost exclusively reserved this procedure for children in cardiopulmonary resuscitation. The EMS provided pain management only to children older than four years of age, but a larger group was in need of analgesia upon arrival of the HEMS, and was subsequently treated by the HEMS.

Conclusions

The Helicopter Emergency Medical Service of the eastern region of the Netherlands brings essential medical expertise in the field not provided by the emergency medical service. The Emergency Medical Service does not provide a significant quantity of procedures obviously needed by the paediatric patient.

The identification of criteria to evaluate prehospital trauma care using the Delphi technique

OBJECTIVE

Current trauma system performance improvement emphasizes hospital- and patient-based outcome measures such as mortality and morbidity, with little focus upon the processes of prehospital trauma care. Little data exist to suggest which prehospital criteria should serve as potential filters. This study identifies the most important filters for auditing prehospital trauma care using a Delphi technique to achieve consensus of expert opinion.

METHODS

Experts in trauma care from the United States (n = 81) were asked to generate filters of potential utility in monitoring the prehospital aspect of the trauma system, and were then required to rank these questions in order of importance to identify those of greatest importance.

RESULTS

Twenty-eight filters ranking in the highest tertile are proposed. The majority (54%) pertains to aspects of emergency medical services, which comprise 7 of the top 10 (70%) filters. Triage filters follow in priority ranking, comprising 29% of the final list. Filters concerning interfacility transfers and transportation ranked lowest.

CONCLUSION

This study identifies audit filters representing the most important aspects of prehospital trauma care that merit continued evaluation and monitoring. A subsequent trial addressing the utility of these filters could potentially enhance the sensitivity of identifying deviations in prehospital care, standardize the performance improvement process, and translate into an improvement in patient care and outcome.

Präklinisches Atemwegsmanagement in Norddeutschland

BACKGROUND

Out-of-hospital airway management confronts emergency medical teams with complex challenges. To date no specific data are available on the qualifications of emergency physicians (EPs) and the quality of emergency equipment in northern Germany.

MATERIALS AND METHODS

This study surveyed individual EPs at regional emergency dispatch centres about their personal knowledge and skills, and the procedures and equipment used in out-of-hospital airway management.

RESULTS

A total of 606 EPs from 59 of the 66 (89.4%) regional emergency dispatch centres surveyed responded and 56.1% of the EPs questioned were anesthesiologists. The other EPs were qualified in either internal medicine (22.6%), surgery (12.4%), general medicine (5.6%) or other specialties (3.3%). All (100%) of the EPs trained in anesthesia and 35.2% of the other EPs reported that they had performed more than 100 in-hospital endotracheal intubations (ETI). 93% of all EPs rated out-of-hospital ETI as more difficult than in-hospital ETI. A total of 33.0% of anesthesia-trained EPs and 6.1% of the other EPs used muscle relaxants for ETI in more than 20% of the cases. Of the anesthesia-trained EPs 38.1% used expiratory CO(2) monitoring to verify tube placement compared to 12.1% of the other EPs. A total of 97.8% of anesthesia-trained EPs reported having used an extra-glottic airway device more than 20 times compared to 11.1% of the other EPs. For the emergency equipment 44.4% included an extraglottic airway device, 57.8% a cricothyrotomy set and 27.1% CO(2) monitoring options.

CONCLUSION

Neither the emergency equipment nor the physicians' knowledge and skills were sufficient to meet the special demands of out-of-hospital airway management, particularly among non-anesthesiologists.

The Out-of-Hospital Esophageal and Endobronchial Intubations Performed by Emergency Physicians

BACKGROUND

Rapid establishment of a patent airway in ill or injured patients is a priority for prehospital rescue personnel. Out-of-hospital tracheal intubation can be challenging. Unrecognized esophageal intubation is a clinical disaster.

METHODS

We performed an observational, prospective study of consecutive patients requiring transport by air and out-of-hospital tracheal intubation, performed by primary emergency physicians to quantify the number of unrecognized esophageal and endobronchial intubations. Tracheal tube placement was verified on scene by a study physician using a combination of direct visualization, end-tidal carbon dioxide detection, esophageal detection device, and physical examination.

RESULTS

During the 5-yr study period 149 consecutive out-of-hospital tracheal intubations were performed by primary emergency physicians and subsequently evaluated by the study physicians. The mean patient age was 57.0 (+/-22.7) yr and 99 patients (66.4%) were men. The tracheal tube was determined by the study physician to have been placed in the right mainstem bronchus or esophagus in 16 (10.7%) and 10 (6.7%) patients, respectively. All esophageal intubations were detected and corrected by the study physician at the scene, but 7 of these 10 patients died within the first 24 h of treatment.

CONCLUSION

The incidence of unrecognized esophageal intubation is frequent and is associated with a high mortality rate. Esophageal intubation can be detected with end-tidal carbon dioxide monitoring and an esophageal detection device. Out-of-hospital care providers should receive continuing training in airway management, and should be provided additional confirmatory adjuncts to aid in the determination of tracheal tube placement.

Needle vs surgical cricothyroidotomy: a short cut to effective ventilation

Cricothyroidotomy can be performed using three techniques. This literature review seeks to determine which is more appropriate for use in prehospital can't intubate/can't ventilate scenarios where laryngeal mask airways prove ineffective. The common approach of inserting a 14-gauge cannula and using low-pressure ventilation via intermittent occlusion of an opening in oxygen tubing (15 l x min(-1) flow) results in ineffective ventilation within 60 s or less, depending on the degree of airway obstruction. In the absence of a high degree of upper airway obstruction, ventilation can be effective if the cannula is attached to a high pressure (45 psi) jet ventilator, but such devices are rare in UK prehospital practice. A self-inflating bag used with a cuffed tube inserted through a horizontal scalpel incision provides sustained adequate ventilation, has a relatively low complication rate compared to needle cricothyroidotomy and is a skill that can be easily taught to paramedics, nurses and doctors.

Out-of-hospital endotracheal intubation: where are we?

While remaining prominent in paramedic care and beneficial to some patients, out-of-hospital endotracheal intubation has not clearly improved survival or reduced morbidity from critical illness or injury when studied more broadly. Recent studies identify equivocal or unfavorable clinical effects, adverse events and errors, interaction with other important resuscitation interventions, and challenges in providing and maintaining procedural skill. We provide an overview of current data evaluating the overall effectiveness, safety, and feasibility of paramedic out-of-hospital endotracheal intubation. These studies highlight our limited understanding of out-of-hospital endotracheal intubation and the need for new strategies to improve airway support in the out-of-hospital setting.

Factors influencing emergency intubation in the pre-hospital setting—a multicentre study in the German Helicopter Emergency Medical Service

BACKGROUND

Definitive airway control by endotracheal intubation (ETI) is standard of care in pre-hospital airway management. However, there are specific factors that may influence and complicate ETI.

METHODS

Prospective, descriptive study at three German Helicopter Emergency Medical Services (HEMS) over a 1-yr period. We examined the success and complication rate for field intubation performed by trauma anaesthetists.

RESULTS

In 342 patients (9.3%) ETI was performed. The overall success rate was 100%; in 87.4% the first attempt was successful, whereas in 11.1% a second and in 1.5% a third ETI attempt was necessary. No patient required a surgical intervention. Limited access to the patient was found upon arrival at the scene in 20.2% of the patients and in 9.6% of the patients at the time of ETI attempt. An orotracheal ETI technique was used in all patients. In the patients in whom only one ETI attempt was necessary for successful intubation, the assessment of ETI conditions was rated 'very good' or 'good' in 94.7%, but in those requiring a second or third ETI attempt this was reduced to 68.6 and 20.0%, respectively. Difficulties encountered during ETI included blood (19.9%), vomit/debris (15.8%) and secretions (13.8%) in the upper airway; anatomical reasons (11.7%), patient position (9.6%) and surrounding conditions (9.1%), making laryngoscopy more difficult.

CONCLUSIONS

Despite various factors increasing the difficulties in managing the airway in the field, definitive airway control by ETI seems to be safe practice.

Prehospital trauma management: a national study of paramedic activities

OBJECTIVES

The benefits of prehospital trauma management remain controversial. This study aimed to compare the processes of care and outcomes of trauma patients treated by paramedics, who are trained in advanced prehospital trauma care, with those treated by ambulance technicians.

METHODS

A six year prospective study was conducted of adult trauma patients attended to by the Scottish Ambulance Service and subsequently admitted to hospital. Prehospital times, interventions, triage, and outcomes were compared between patients treated by paramedics and those treated by technicians.

RESULTS

Paramedics attended more severely injured patients (16.5% versus 13.9%, p<0.001); they attended a higher proportion of patients with penetrating trauma (6.6% versus 5.7%, p = 0.014) and had longer prehospital times. Patients managed by paramedics were more likely to be taken to the intensive care unit, operating theatre or mortuary, (11.2% versus 7.8%, p<0.001) and had higher crude mortality rates (5.3% versus 4.5%, p = 0.07). However, no difference in mortality between the two groups was noted when corrected for age, Glasgow coma score and injury severity score.

CONCLUSIONS

This large scale national study shows that paramedics show good triage skills and clinical judgement when managing trauma patients. However, the value of the individual interventions they perform could not be ascertained. Further controlled trials are necessary to determine the true benefits of advanced prehospital trauma life support.

Emergency medical services in Japan: An opportunity for the rational development of pre-hospital care and research

Japan is at a crossroads in the development of its Emergency Medical Services (EMS). At present, Japan has an essentially pure scoop-and-run, defibrillation system. However, there is a strong movement toward expanding the scope of paramedic practice to include more complex, Advanced Life Support (ALS) and trauma protocols to its nationally standardized pre-hospital protocols. The implications of introducing complex pre-hospital protocols guided by the use of existing scientific evidence to support such action is discussed in the context of Japan's unique opportunity to test many fundamental questions in pre-hospital medical care and the public's understanding and acceptance of these practices. Japan, a technologically advanced country that is not encumbered by entrenched "standards of care," has the opportunity to develop an efficient and rational EMS system.

Detrimental hemodynamic effects of assisted ventilation in hemorrhagic states

OBJECTIVE

Our goal was to demonstrate explicitly that lower-frequency positive-pressure ventilation not only preserves adequate oxygenation and acid-base status in hemorrhagic states, but also that "normal" or higher respiratory rates significantly compromise hemodynamics, even with moderate degrees of hemorrhage.

DESIGN AND SUBJECTS

Eight intubated pigs (ventilated with 12 mL/kg tidal volume, 28% FIO2, respiratory rate = 12 breaths/min) were hemorrhaged to <65 mm Hg of systolic blood pressure. Respiratory rates were then sequentially changed every 10 mins to 6, 20, 30, and 6 breaths/min.

MEASUREMENTS AND MAIN RESULTS

With respiratory rates at 6 breaths/min, all subjects maintained pH of >7.25 and SaO2 of >99% while increasing systolic blood pressure (mean, 65-84 mm Hg; p < .05), time-averaged coronary perfusion pressure (50 +/- 2 to 60 +/- 4 mm Hg; p < .05), and cardiac output (2.4 to 2.8 L/min; p < .05). With respiratory rates of 20 and 30 breaths/min, systolic blood pressure (73 +/- 4 and 66 +/- 5 mm Hg, respectively), coronary perfusion pressure (47 +/- 3 and 42 +/- 4 mm Hg), and cardiac output (2.5 and 2.4 L/min) diminished. When returned to 6 breaths/min, systolic blood pressure (95 mm Hg), coronary perfusion pressure (71 + 6 mm Hg), and cardiac output (3.0 L/min) improved significantly (p < .05 for all comparisons).

CONCLUSIONS

After moderate hemorrhage, animals maintain adequate oxygenation and acid-base status with lower-frequency respiratory rates, whereas increasingly higher respiratory rates progressively and significantly impair hemodynamics. Current ventilatory protocols for trauma resuscitation should be re-examined and considered a possible cause of worsened clinical outcomes and unrecognized confounded study results.

Emergency physician-verified out-of-hospital intubation: miss rates by paramedics

OBJECTIVES

To prospectively quantify the number of unrecognized missed out-of-hospital intubations by ground paramedics using emergency physician verification as the criterion standard for verification of endotracheal tube placement.

METHODS

The authors performed an observational, prospective study of consecutive intubated patients arriving by ground emergency medical services to two urban teaching hospitals. Endotracheal tube placement was verified by emergency physicians and evaluated by using a combination of direct visualization, esophageal detector device (EDD), colorimetric end-tidal carbon dioxide (ETCO(2)), and physical examination.

RESULTS

During the six-month study period, 208 out-of-hospital intubations by ground paramedics were enrolled, which included 160 (76.9%) medical patients and 48 (23.1%) trauma patients. A total of 12 (5.8%) endotracheal tubes were incorrectly placed outside the trachea. This comprised ten (6.3%) medical patients and two (4.2%) trauma patients. Of the 12 misplaced endotracheal tubes, a verification device (ETCO(2) or EDD) was used in three cases (25%) and not used in nine cases (75%).

CONCLUSIONS

The rate of unrecognized, misplaced out-of-hospital intubations in this urban, midwestern setting was 5.8%. This is more consistent with results of prior out-of-hospital studies that used field verification and is discordant with the only other study to exclusively use emergency physician verification performed on arrival to the emergency department.

Rapid response car as a supplement to the helicopter in a physician-based HEMS system

BACKGROUND

The purpose of this study was to describe the use of a rapid response car (RRC) as a supplement to the ambulance helicopter in a mixed urban/rural region in Norway.

METHODS

Data from all the requested missions were collected from standard flight records. Operational factors, patient characteristics, primary diagnosis, treatment and modes of transport were registered and analyzed retrospectively.

RESULTS

In 1999-2001, a total of 4777 requests were included in the study, resulting in the initiation of 3172 helicopter and 752 RRC missions. In the RRC missions, 224 patients received advanced medical treatment that would otherwise not have been provided. For 181 patients, the availability of the RRC was crucial for receiving the treatment of the helicopter emergency medical services (HEMS). The cost of equipping the base with the RRC increased the annual budget by less than one percent.

CONCLUSION

The RRC was essential for solving missions in periods of non-flying conditions. The RRC increased the availability of the advanced prehospital life support offered by the HEMS in this region. Taking the modest increase in cost into consideration, it seems reasonable that this HEMS, covering mixed urban and rural areas, is equipped with such a vehicle.

Initial management of the trauma patient

Critical care specialists should be familiar with the initial management of injured patients. Dividing the evaluation and treatment of the patient into the primary, secondary, and tertiary surveys ensures that the multiply injured patient will be managed expeditiously. The primary survey identifies the acute life-threatening problems that must be managed immediately. The secondary survey identifies the remaining major injuries and sets priorities for definitive management. The tertiary survey identifies occult injuries before they become missed injuries.

Emergency ventilatory management in hemorrhagic states: elemental or detrimental?

BACKGROUND

A study was performed to demonstrate that slower respiratory rates (RRs) of positive-pressure ventilation can preserve adequate oxygenation and acid-base status in hemorrhagic states, whereas "normal" or higher RRs worsen hemodynamics.

METHODS

Eight swine (ventilated with 12 mL/kg tidal volume, 0.28 Fio(2); RR of 12 breaths/min) were hemorrhaged to < 65 mm Hg systolic arterial blood pressure (SABP). RRs were then sequentially changed every 10 minutes to 6, 20, 30, and 6 breaths/min.

RESULTS

With RRs at 6 breaths/min, the animals maintained pH > 7.25/Sao(2) > 99%, but increased mean SABP (from 65 to 84 mm Hg; p < 0.05), time-averaged coronary perfusion pressure (CPP) (from 50 +/- 2 to 60 +/- 4 mm Hg; p < 0.05), and cardiac output (Qt) (from 2.4 to 2.8 L/min; p < 0.05). With RRs of 20 and 30 breaths/min, SABP (73 and 66 mm Hg), CPP (47 +/- 3 and 42 +/- 4 mm Hg), and Qt (2.5 and 2.4 L/min) decreased, as did Pao(2) and Paco(2) (< 30 mm Hg), with p < 0.05 for each comparison, respectively. When RR returned to 6 breaths/min, SABP (95 mm Hg), CPP (71 +/- 6 mm Hg), and Qt (3.0 L/min) improved significantly (p < 0.05).

CONCLUSION

After even moderate levels of hemorrhage in animals, positive-pressure ventilation with "normal" or higher RRs can impair hemodynamics. Hemodynamics can be improved with lower RRs while still maintaining adequate oxygenation and ventilation.

Comparison of a conventional tracheal airway with the Combitube in an urban emergency medical services system run by physicians

This prospective randomised study was performed to compare the use of the Esophageal-Tracheal Combitube(R) (ETC; Tyco Healthcare, Mansfield, MA; http://www.combitube.org) with a conventional tracheal airway (ETA) for airway management by experienced physicians of the Emergency Medical Services System of the City of Vienna in the prehospital setting. Access to the patient's head, time of arrival of the ambulance, ease of insertion, time of insertion, potential substitution by the alternate airway, efficacy of adrenaline (epinephrine) administered via the airway, survival to the intensive care unit (ICU) ward and survival to discharge from the hospital were evaluated. One hundred and seventy-two non-traumatic cardiac arrest patients (131 males, 41 females) were enrolled in this study during a 12 months period. In 83 patients (48.3%), the conventional ETA (group 1) was used for the initial intubation attempt which was successful in 78 patients (94%). The remaining five patients of group 1 could not be intubated with an ETA, but were successfully managed with the ETC. Eighty-nine patients (51.7%) were intubated with the ETC (group 2) as first choice (79 in oesophageal position (89%); eight in tracheal position: (9%)), which was successful in 87 (98%) patients. The remaining two patients in group 2 (2%) were successfully managed with the ETA. Success of intubation and ventilation with ETC was comparable to the ETA. Recorded time of insertion was shorter with the ETC versus ETA (P<0.05). The Combitube worked well in cases of difficult access to the patient's head and in bleeding and vomiting patients. Both devices served as successful substitutes for each other. Adrenaline (epinephrine) applied via ETC with a 10-fold dosage was as effective as via the conventional ETA. To our knowledge this is the first study using physicians comparing ETC and ETA in the prehospital setting.