Monthly Archives: January 2014

The feasibility of civilian prehospital trauma teams carrying and administering packed red blood cells

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© Gary Wilson/ Pre-hospital Research Forum

© Gary Wilson/ Pre-hospital Research Forum

The feasibility of civilian prehospital trauma teams carrying and administering packed red blood cells

Emerg Med J 2014;31:93-95

To evaluate the feasibility, limitations and costs involved in providing prehospital trauma teams with packed red blood cells (pRBCs) for use in the prehospital setting.

Methods A retrospective cohort study, examining 18 months of historical data collated by the Queensland Ambulance Service Trauma Response Team (TRT) and the Pathology Queensland Central Transfusion Laboratory was undertaken.

Results Over an 18-month period (1 January 2011–30 June 2012), of 500 pRBC units provided to the TRT, 130 (26%) were administered to patients in the prehospital environment. Of the non-transfused units, 97.8% were returned to a hospital blood bank and were available for reissue. No instances of equipment failure directly contributed to wastage of pRBCs. The cost of providing pRBCs for prehospital use was $A551 (£361) for each unit transfused.

Conclusions The authors found it is feasible and practical to provide prehospital trauma teams with pRBCs for use in the field. Use of pRBCs in the prehospital setting is associated with similar rates of pRBC wastage to that reported in emergency departments.

http://emj.bmj.com/content/31/2/93?etoc

Improvement in the prehospital recognition of tension pneumothorax

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Improvement in the prehospital recognition of tension pneumothorax: The effect of a change to paramedic guidelines and education

Injury. Volume 45, Issue 1, January 2014, Pages 71–76

An audit of ambulance service clinical records from 2001 to 2002 in Melbourne, Australia revealed 10 patients with tension pneumothorax on arrival at hospital which had been undetected or untreated by paramedics. The clinical practice guideline for paramedic recognition of tension pneumothorax was subsequently changed to emphasise heightened clinical suspicion of a tension pneumothorax in the setting of chest trauma, especially when patients were managed with positive pressure ventilation.

This study was undertaken to determine whether the number of undetected or untreated tension pneumothoraces had decreased after the new clinical practice guideline and associated education program; if there were unintended consequences arising from earlier paramedic intervention; and what effect, if any, this change had on subsequent hospital treatment.

Methods
Retrospective case note review of all patients requiring intercostal catheter (ICC) insertion at The Alfred Hospital, Melbourne, Australia, using records from Ambulance Victoria, the Alfred Trauma Registry and the National Coronial Information System.

Results
In 2001–2002 paramedics treated 22 patients with suspected tension pneumothorax before transport to the Alfred Hospital. In 2006–2007 this number had increased to 81. There was a decrease from ten to four in the number of unrecognised or untreated tension pneumothoraces between the two time periods. No unintended or adverse consequences of prehospital needle decompression could be found. However, there was an increase in the number of patients who had prehospital needle decompression that needed further treatment for tension pneumothorax on arrival at hospital. This need for further treatment was associated with use of shorter cannulas and unilateral needle decompression by paramedics.

Conclusion
A small change in clinical practice guidelines, supported by an education and audit program, led to a reduction in unrecognised untreated tension pneumothoraces by paramedics without an increase in complications. Paramedics should be aware that a shorter cannula may fail to reach the pleural space and that both sides of the chest may require decompression.

http://www.sciencedirect.com/science/article/pii/S0020138313002891

Prehospital anaesthesia performed in a rural and suburban air ambulance service staffed by a physician and paramedic

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Prehospital anaesthesia performed in a rural and suburban air ambulance service staffed by a physician and paramedic: a 16-month review of practice

© Gary Wilson/ Pre-hospital Research Forum

© Gary Wilson/ Pre-hospital Research Forum

Emerg Med J 2014;31:65-68 

This paper describes the first 16-months experience of prehospital rapid sequence intubation (RSI) in a rural and suburban helicopter-based doctor-paramedic service after the introduction of a standard operating procedure (SOP) already proven in an urban trauma environment.

Method A retrospective database review of all missions between October 2010 and January 2012 was carried out. Any RSI or intubation carried out was included, regardless of age or indication. Patients who were intubated by Ambulance Service personnel prior to the arrival of the East Anglian Air Ambulance (EAAA) team were excluded.

Results The team was activated 1156 times and attended 763 cases. A total of 88 RSIs occurring within the study period were identified as having been carried out by the EAAA team and meeting inclusion criteria for review. There were no failed intubations that required a rescue surgical airway or the placement of a supraglottic airway device. For road traffic collisions (RTCs), the overall on-scene time for patients who required an RSI was 40 min (range 15–72 min). For all other trauma, the average on-scene time was 48 min (range 25–77 min), and for medical patients, the average time spent at scene was 41 min (range 15–94 min).

Conclusions The authors have demonstrated the successful introduction of a prehospital care SOP, already tested in the urban trauma environment, to a rural and suburban air ambulance service operating a fulltime doctor-paramedic model. The authors have shown a zero failed intubation rate over 16 months of practice during which time over 750 missions were flown, with 11.5% of these resulting in an RSI.

Further details on the UK air ambulances SOP for RSI can be found here: HEMS SOP and RSI checklist.  The research article lists “six indications for an RSI in the prehospital setting:

(1) actual or impending airway failure;
(2) ventilatory failure;
(3) unconsciousness;
(4) humanitarian indications;
(5) injured patients who are unmanageable or severely agitated after a head injury and
(6) anticipated clinical course.

“The patient is placed in a position away from direct sunlight, ideally with 360o access space. After adequate preoxygenation, a standard sequence of etomidate followed by suxamethonium is administered, and the tracheal tube is placed under direct vision and always over an intubating bougie. Following confirmation of correct tracheal tube placement, anaesthesia is maintained with boluses of morphine and midazolam, and neuromuscular blockade is continued with pancuronium. In the event of a failed intubation, there is a well-rehearsed sequence of immediate ‘drills’ to perform in order to improve intubation conditions, and after a second failed attempt, or if there is failure to adequately oxygenate or ventilate at any time, a supraglottic airway is placed, or a surgical airway is performed.”

http://emj.bmj.com/content/31/1/65.abstract

Performance of Experienced Versus Less Experienced Paramedics in Managing challenging scenarios

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Performance of Experienced Versus Less Experienced Paramedics in Managing Challenging Scenarios: A Cognitive Task Analysis Study

Annals of Emergency Medicine. Volume 62, Issue 4, October 2013, Pages 367–379

© Gary Wilson/ Pre-hospital Research Forum

© Gary Wilson/ Pre-hospital Research Forum

Out-of-hospital care is becoming more complex, thus placing greater reliance on the cognitive abilities of paramedics to manage difficult situations. In adapting to the challenges in their work, paramedics develop expertise. We study the cognitive strategies used by expert paramedics to contribute to understanding how paramedics and the EMS system can adapt to new challenges.

Methods
The authors conducted a “staged-world” cognitive task analysis to explore paramedics’ handling of cognitive challenges related to sense-making and to resource and task management. A mixed-fidelity simulation was used to present paramedics with 2 challenging scenarios: a pulmonary embolism initially presenting as a myocardial infarction and a 2-person shooting with limited resources available.

Results
Participants were 10 paramedics, 6 more experienced and 4 less experienced. Analysis involved comparing the performance of the 2 groups to identify strategies associated with expertise. The more experienced paramedics made more assessments, explored a wider variety of presumptive diagnoses, and identified the pulmonary embolism earlier. They switched attention between the 2 shooting victims more, used their emergency medical technician–basic level partners more, and provided more advanced level care for both patients. Their patients arrived at the emergency department more prepared for specialized emergency care.

Conclusion
The authors’findings correspond to general cognitive attributes of expertise: greater cue gathering and inferential reasoning, and more functional and strategic thinking. These results suggest potential areas and methods to facilitate development of expertise, as well as ways to better support use of expertise. Future studies should expand on these findings through larger sample sizes and more complex scenarios.

http://www.sciencedirect.com/science/article/pii/S0196064413004162

Therapeutic hypothermia following out-of-hospital cardiac arrest

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Another study questioning therapeutic hypothermia has been published following the recent publication of two research studies which resulting in several organisations, including the European Resuscitation Council and ILCOR to issue statements on targeted temperature management.

© Gary Wilson/ Pre-hospital Research Forum

© Gary Wilson/ Pre-hospital Research Forum

Comparative Effectiveness of Therapeutic Hypothermia After Out-of-Hospital Cardiac Arrest: Insight from a Large Data Registry

Therapeutic Hypothermia and Temperature Management. Online Ahead of Print: December 28, 2013

This study was undertaken by the authors to determine the effectiveness of therapeutic hypothermia (TH) after out-of-hospital cardiac arrest (OHCA) among a large cohort of adults in the Cardiac Arrest Registry to Enhance Survival (CARES), with an emphasis on subgroups with a non-shockable first documented rhythm.

All adult index events at participating sites from November 2010 to December 2013 were study eligible. All patient data elements were provided with summary statistics calculated for all patients with and without TH. For multivariate adjustment, a multilevel (i.e., hierarchical), mixed-effects logistic regression (MLR) model was used with hospitals treated as random effects. Propensity score matching (PSM) on both shockable and non-shockable patients was done as a sensitivity analysis. After predefined exclusions, our final sample size was 6369 records for analysis: shockable=2992 (47.0%); asystole=1657 (26.0%); pulseless electrical activity=1249 (19.6%); other unspecified non-shockable=471 (7.4%). Unadjusted differences in neurological status at hospital discharge with and without TH were similar (p=0.295).

After multivariate adjustment, TH had either no association with good neurological status at hospital discharge or that TH was actually associated with worse neurological outcome, particularly in patients with a non-shockable first documented rhythm (i.e., for NS patients, MLR odds ratio for TH=1.444; 95% CI [1.039, 2.006] p=0.029, and OR=1.017, p=0.927 via PSM).

Highlighting the limitations, the authors concluded that when TH is indiscriminately provided to a large population of OHCA survivors with a non-shockable first documented rhythm, evidence for its effectiveness is diminished. The authors suggest more uniform and rigid guidelines for the application of TH.

http://online.liebertpub.com/doi/abs/10.1089/ther.2013.0018

This was published only a month after the European Resuscitation Council issued a statement (https://www.erc.edu/index.php/docLibrary/en/viewDoc/2083/3/) on target temperature management following two studies into the treatment of patients with ROSC after out-of-hospital cardiac arrest (OHCA) arise from these studies, questioning whether:

1. Should ice-cold intravenous fluid continue to be used for inducing hypothermia prehospital?
2. Should the target temperature be 32-34 °C or 36 °C for the management of comatose cardiac arrest survivors with ROSC?

Shortly after the European Resuscitation Council (ERC) released the statement, International Liaison Committee on Resuscitation (ILCOR)  published an advisory statement to guide clinicians on the use of temperature management in post cardiac arrest patients (http://www.ilcor.org/data/TTM-ILCOR-update-Dec-2013.pdf)

According to ILCOR: “A key message from this study is that targeted temperature management (TTM) remains an important component of the post resuscitation care of the unconscious cardiac arrest patient and that similar results were obtained when either 33ºC or 36ºC were selected as target temperature.”

With regard to choosing that temperature to cool your patients, the following advice was issued: ” Pending formal consensus on the optimal temperature, we suggest that clinicians provide post-resuscitation care based on the current treatment recommendations” and “We accept that some clinicians may make a local decision to use a target temperature of 36°C pending this further guidance”. Further formal discussions are being undertaken by ILCOR regarding future decisions on targeted temperature management.

Below are details on the original two studies which sparked the release of the advisory statements:

Targeted Temperature Management at 33°C versus 36°C after Cardiac Arrest found no difference in survival when lowering cardiac arrest patients’ temperature to 33 °C vs. 36 °C. [N Engl J Med 2013; 369:2197-2206 December 5, 2013]

Unconscious survivors of out-of-hospital cardiac arrest have a high risk of death or poor neurologic function. Therapeutic hypothermia is recommended by international guidelines, but the supporting evidence is limited, and the target temperature associated with the best outcome is unknown. The authors objective was to compare two target temperatures, both intended to prevent fever.

METHODS
In an international trial, the authors randomly assigned 950 unconscious adults after out-of-hospital cardiac arrest of presumed cardiac cause to targeted temperature management at either 33°C or 36°C. The primary outcome was all-cause mortality through the end of the trial. Secondary outcomes included a composite of poor neurologic function or death at 180 days, as evaluated with the Cerebral Performance Category (CPC) scale and the modified Rankin scale.

RESULTS
In total, 939 patients were included in the primary analysis. At the end of the trial, 50% of the patients in the 33°C group (235 of 473 patients) had died, as compared with 48% of the patients in the 36°C group (225 of 466 patients) (hazard ratio with a temperature of 33°C, 1.06; 95% confidence interval [CI], 0.89 to 1.28; P=0.51). At the 180-day follow-up, 54% of the patients in the 33°C group had died or had poor neurologic function according to the CPC, as compared with 52% of patients in the 36°C group (risk ratio, 1.02; 95% CI, 0.88 to 1.16; P=0.78). In the analysis using the modified Rankin scale, the comparable rate was 52% in both groups (risk ratio, 1.01; 95% CI, 0.89 to 1.14; P=0.87). The results of analyses adjusted for known prognostic factors were similar.

CONCLUSIONS
In unconscious survivors of out-of-hospital cardiac arrest of presumed cardiac cause, hypothermia at a targeted temperature of 33°C did not confer a benefit as compared with a targeted temperature of 36°C.

http://www.nejm.org/doi/full/10.1056/NEJMoa1310519

Effect of Prehospital Induction of Mild Hypothermia on Survival and Neurological Status Among Adults With Cardiac Arrest: A Randomized Clinical Trial was the second study which resulted in the statement. (JAMA. 2014;311(1):45-52.)

Objective To determine whether prehospital cooling improves outcomes after resuscitation from cardiac arrest in patients with ventricular fibrillation (VF) and without VF.

Design, Setting, and Participants A randomised clinical trial that assigned adults with prehospital cardiac arrest to standard care with or without prehospital cooling, accomplished by infusing up to 2 L of 4°C normal saline as soon as possible following return of spontaneous circulation. Adults in King County, Washington, with prehospital cardiac arrest and resuscitated by paramedics were eligible and 1359 patients (583 with VF and 776 without VF) were randomized between December 15, 2007, and December 7, 2012. Patient follow-up was completed by May 1, 2013. Nearly all of the patients resuscitated from VF and admitted to the hospital received hospital cooling regardless of their randomisation.

Main Outcomes and Measures The primary outcomes were survival to hospital discharge and neurological status at discharge.

Results The intervention decreased mean core temperature by 1.20°C  in patients with VF and by 1.30°C  in patients without VF by hospital arrival and reduced the time to achieve a temperature of less than 34°C by about 1 hour compared with the control group. However, survival to hospital discharge was similar among the intervention and control groups among patients with VF (62.7% vs 64.3%) and among patients without VF (19.2% vs 16.3%). The intervention was also not associated with improved neurological status of full recovery or mild impairment at discharge for either patients with VF (57.5% of cases had full recovery or mild impairment vs 61.9% or those without VF (14.4% of cases vs 13.4% of controls). Overall, the intervention group experienced rearrest in the field more than the control group (26%  vs 21% ), as well as increased diuretic use and pulmonary oedema on first chest x-ray, which resolved within 24 hours after admission.

Conclusion and Relevance Although use of prehospital cooling reduced core temperature by hospital arrival and reduced the time to reach a temperature of 34°C, it did not improve survival or neurological status among patients resuscitated from prehospital VF or those without VF.

http://jama.jamanetwork.com/article.aspx?articleid=1778673&resultClick=3