A meta-analysis of pre-hospital airway control techniques evaluated alternative techniques to tracheal intubation. The outcome was placement success; there were no data on effectiveness of ventilation or other clinical outcomes. Although limited by poor quality studies, there are some interesting findings.
The pooled placement success rates for Combitube and LMA, were similar but unimpressive, with nonphysician placement success rates of 83.0% and 82.7%, respectively. The authors point out that while these devices might offer potential advantages over conventional tracheal intubation in terms of reduced training requirements, or perhaps fewer or less severe complications, they should not be expected to provide higher airway management success rates than conventional tracheal intubation.
They identified only four studies reporting the success rates of needle cricothyroidotomy (NC). Regardless of patient circumstances or clinician credentials, the NC success rate was ubiquitously low, ranging from 25.0% to 76.9%. The pooled results for the 18 surgical cricothyroidotomy (SC) studies produced substantially higher success rates, although the success rate for all nonphysician clinicians was still only 90.4%. The authors state: “EMS systems that choose to incorporate a percutaneous airway procedure into their airway management protocols should recognize that the success rate of SC far exceeds that of NC”.
A meta-analysis of prehospital airway control techniques part II: alternative airway devices and cricothyrotomy success rates
Prehosp Emerg Care. 2010 Oct-Dec;14(4):515-30
Category Archives: PHARM
Prehospital and Retrieval Medicine
High flow O2 and mortality in COPD
An Australian randomised controlled trial of pre-hospital oxygen therapy in COPD patients compared titrated oxygen therapy with high flow oxygen. The primary outcome was prehospital and in-hospital mortality.
Titrated oxygen treatment was delivered by nasal prongs to achieve arterial oxygen saturations between 88% and 92%, with concurrent bronchodilator treatment administered by a nebuliser driven by compressed air. High flow oxygen was 8-10 l/min administered by a non-rebreather face mask, with bronchodilators delivered by nebulisation with oxygen at flows of 6-8 l/min.
Titrated oxygen treatment significantly reduced mortality, hypercapnia, and respiratory acidosis compared with high flow oxygen in acute exacerbations of chronic obstructive pulmonary disease. The authors claim: ‘For high flow oxygen treatment in patients with confirmed chronic obstructive pulmonary disease in the prehospital setting, the number needed to harm was 14; that is, for every 14 patients who are given high flow oxygen, one will die.‘
The authors did not report data on the in-hospital management of the patients.
Effect of high flow oxygen on mortality in chronic obstructive pulmonary disease patients in prehospital setting: randomised controlled trial
BMJ. 2010 Oct 18;341:c5462
Titrated oxygen treatment significantly reduced mortality, hypercapnia, and respiratory acidosis compared with high flow oxygen in acute exacerbations of chronic obstructive pulmonary disease. The authors claim: ‘For high flow oxygen treatment in patients with confirmed chronic obstructive pulmonary disease in the prehospital setting, the number needed to harm was 14; that is, for every 14 patients who are given high flow oxygen, one will die.‘
The authors did not report data on the in-hospital management of the patients.
Effect of high flow oxygen on mortality in chronic obstructive pulmonary disease patients in prehospital setting: randomised controlled trial
BMJ. 2010 Oct 18;341:c5462
Scene times for rural retrieval in Scotland
The Emergency Medical Retrieval Service (EMRS) provides an aeromedical retrieval service to remote and rural communities in Scotland. They examined 300 retrievals over a five year period and showed a correlation between amount of critical care interventions required and total time on scene (defined as the total length of time between the aircraft landing and taking off from the scene, this includes access to patient, transfer to the helicopter and packaging for flight departure). Median scene time for both medical and trauma patients was 60 minutes.
The authors remind us that critical care secondary retrieval from rural healthcare facilities has many similarities to prehospital care (primary retrieval), and therefore consideration of scene times is of interest.
On-scene times and critical care interventions for an aeromedical retrieval service
Emerg Med J. 2010 Aug 19. [Epub ahead of print]
Paediatric arrest outcomes
A study of out-of-hospital paediatric arrests in Melbourne gives some useful outcome data: overall, paediatric victims of out-of-hospital cardiac arrest survived to leave hospital in 7.7% of cases, which is similar to adult survival in the same emergency system (8%). Survival was very rare (<1%) unless there was return of spontaneous circulation prior to hospital arrival. Sixteen of the 193 cases studied had trauma, but the survival in this subgroup was not specifically documented.
Epidemiology of paediatric out-of-hospital cardiac arrest in Melbourne, Australia
Resuscitation. 2010 Sep;81(9):1095-100
Ketamine for HEMS intubation in Canada
Ketamine was used by clinical staff from the The Shock Trauma Air Rescue Society (STARS) in Alberta to facilitate intubation in both the pre-hospital & in-hospital setting (with a neuromuscular blocker in only three quarters of cases). Changes in vital signs were small despite the severity of illness in the study population.
A prospective review of the use of ketamine to facilitate endotracheal intubation in the helicopter emergency medical services (HEMS) setting
Emerg Med J. 2010 Oct 6. [Epub ahead of print]
Scene times & penetrating trauma
An observational cohort study of penetrating trauma patients treated by the Mobile Emergency Care Unit in Copenhagen, Denmark over a seven-and-a-half year period sought to determine the effect of on-scene time on 30-day mortality.
In this setting, in cases of penetrating trauma to the chest, or abdomen, a Mobile Emergency Care Unit (MECU) and Basic Life Support unit are dispatched simultaneously, and rendezvous at the site of the incident. The MECU is staffed with consultants in anaesthesiology, intensive care and emergency medicine, as well as a specially trained ALS provider.
The physician manning the MECU administers medication and is able to perform procedures such as intubation, thoracocentesis, pleural drainage, intravenous and intraosseous access for fluid resuscitation. Although some patients were in cardiac arrest due to penetrating torso trauma (9 patients received chest compressions, and all were dead at 30 follow up), thoracotomy was not listed as a skill provided.
Of the 467 patients registered, 442 (94.6%) were identified at the 30-day follow-up, of whom 40 (9%) were dead. A higher mortality was found among patients treated on-scene for more than 20 min (p<0.0001), although on-scene time was not a significant predictor of 30-day mortality in the multivariate analysis; OR 3.71, 95% CI 0.66 to 20.70 (p<0.14). The number of procedures was significantly correlated to a higher mortality in the multivariate analysis.
The authors conclude that on-scene time might be important in penetrating trauma, and ALS procedures should not delay transport to definite care at the hospital. However their adjusted Odds Ratio for on scene time >20 minutes as a predictor of 30 day mortality was 3.71 with very wide 95% confidence intervals (0.66 to 20.70) and there were several weaknesses and confounding factors in the study which the authors acknowledge.
The only real information this study provides appears to be on the idiosyncrasies of the Copenhagen pre-hospital care system. Looking at their list of procedures and their practice of chest compressions in cardiac arrest due to penetrating trauma, it is very hard to ascertain what, if any, advantage their physicians offer over trained paramedics. As the authors point out: “Currently, strict guidelines are not practiced. Hence, the decision to treat by a ‘scoop and run’ or a ‘stay and play’ approach is at the discretion of the physician”
On-scene time and outcome after penetrating trauma: an observational study
Emerg Med J. 2010 Oct 9. [Epub ahead of print]
Pre-hospital RSI by different specialties
This aim of the study was to evaluate the tracheal intubation success rate of doctors drawn from different clinical specialities performing rapid sequence intubation (RSI) in the pre-hospital environment operating on the Warwickshire and Northamptonshire Air Ambulance. Over a 5-year period, RSI was performed in 200 cases (3.1/month).
Failure to intubate was declared if >2 successive attempts were required to achieve intubation or an ETT could not be placed correctly necessitating the use of an alternate airway. Successful intubation occurred in 194 cases, giving a failure rate of 3% (6 cases, 95% CI 0.6 to 5.3%). While no difference in failure rate was observed between emergency department (ED) staff and anaesthetists (2.73% (3/110, 95% CI 0 to 5.7%) vs 0% (0/55, 95% CI 0 to 0%); p=0.55), a significant difference was found when non-ED, non- anaesthetic staff (GP and surgical) were compared to anaesthetists (10.34% (3/29, 95% CI 0 to 21.4%) vs 0%; p=0.04). There was no significant difference associated with seniority of practitioner (p=0.65). The authors conclude that non-anaesthetic practitioners have a higher tracheal intubation failure rate during pre-hospital RSI, which may reflect a lack of training opportunities.
The small numbers of ‘failure’ rates, combined with the definition of failure in this study, make it hard to draw generalisations. Of note is that the paper lists the outcomes of the six patients who met the failed intubation definition, all of whom appear to have had their airway satisfactorily maintained by the RSI practitioner, three by eventual tracheal intubation, one by LMA, and two by surgical airway. More data are needed before whole specialties are judged on the performance of a small group of doctors.
Should non-anaesthetists perform pre-hospital rapid sequence induction? an observational study
Emerg Med J. 2010 Jul 26. [Epub ahead of print]
EM trainee RSI experience
A single centre observational study of rapid sequence intubation (RSI) was performed in a Scottish Emergency Department (ED) over four and a quarter years, followed by a postal survey of ED RSI operators.
There were 329 RSIs during the study period. RSI was performed by emergency physicians (both trained specialists and training grade, or ‘registrar’ doctors) in 288 (88%) patients. Complication rates were low and there were only two failed intubations requiring surgical airways (0.6%). ED registrars were the predominant RSI operator, with 206 patients (63%). ED consultants performed RSIs on 82 (25%) patients, anaesthetic registrars on 31 (9.4%) patients, and anaesthetic consultants on 8 (2.4%) patients. An ED consultant was present during every RSI performed and an anaesthetist was present during 72 (22%). The average number of ED registrars during this period of training was 8. This equates to each ED trainee performing approximately 26 ED RSIs (6.5 RSIs/year). On average, ED consultants performed 14 RSIs during this period (approx 3.5 RSIs/year). Of the 17 questionnaires, 12 were completed, in all of which cases the trainees were confident to perform RSI independently at the end of registrar training. Interestingly, 45 (14%) of the RSIs in the study were done in the pre-hospital environment by ED staff, two thirds of which were done by ED consultants.
Training and competency in rapid sequence intubation: the perspective from a Scottish teaching hospital emergency department
Emerg Med J. 2010 Sep 15. [Epub ahead of print]
AED Use in Children Now Includes Infants
From the new 2010 resuscitation guidelines:
For attempted defibrillation of children 1 to 8 years of age with an AED, the rescuer should use a pediatric dose-attenuator system if one is available. If the rescuer provides CPR to a child in cardiac arrest and does not have an AED with a pediatric dose-attenuator system, the rescuer should use a standard AED. For infants (<1 year of age), a manual defibrillator is preferred. If a manual defibrillator is not available, an AED with pediatric dose attenuation is desirable. If neither is available, an AED without a dose attenuator may be used.
Summary: Adult AEDs may be used in all infants and children if there is no child-specific alternative
Highlights of the 2010 American Heart Association Guidelines for CPR and ECC
Resuscitation Guideline Changes
The European Resuscitation Council’s Summary of Major Changes in the 2010 guidelines can be downloaded here
