Tag Archives: HEMS

Hilar Twists & Human Error

An engaging scene from ‘Code Blue‘ demonstrated a Helicopter Emergency Medical Service team managing a patient with major thoracic haemorrhage. They did a right thoracotomy and wanted to clamp the hilum but there was some kit missing from the pack.

Unfortunately, the video is no longer available.

This scene had some great discussion points for prehospital professionals, even if the specific scenario is somewhat unlikely for most people’s practice:

  • Non-compressible haemorrhage is possibly the biggest single clinical challenge when you’re a long way from hospital
  • Agitated friends and family can be disruptive – allocate a rescuer to look after them
  • Having blood products to give is essential
  • Don’t rely on the memory of individuals, who are fallible, to pack your equipment. “I was sure I put them in” didn’t cut it when the team needed forceps to clamp the pulmonary hilum and stop the bleeding. Checklists are the in thing, for good reason.
  • Luckily, you don’t need to clamp the hilum (which is tricky) in massive unilateral thoracic haemorrhage. You can just twist the lung 180 degrees on the hilum so it’s upside down. This can prevent further haemorrhage and air embolism.

What’s a hilar twist then?

The hilar twist manoeuvre, as it’s called, is worth learning if you’re a clinician who is prepared to do resuscitative clamshell thoracotomy for penetrating traumatic cardiac arrest. The clamshell is quick and provides excellent exposure(1) and is preferred to lateral thoracotomy(2).

The primary purpose of clamshell thoracotomy in penetrating traumatic arrest is to relieve cardiac tamponade and control a cardiac wound(3). It is well described and continues to save lives in the prehospital setting(4).

However, sometimes you’ll open the chest and the pericardium will be empty (other than containing the heart of course), and there will be massive haemorrhage on one side of the chest. Although most of these patients will be unsalvageable outside a trauma centre’s operating room, it’s worth trying something once you’ve gone to all the trouble of opening the chest. The hilar twist(5) is probably the best option for the non-surgeon, especially when some muppet’s forgotten to pack a clamp.

In order to make the lung mobile enough to twist, it’s first necessary to cut through the inferior pulmonary ligament. This is also known as simply the pulmonary ligament (because there’s no superior equivalent) and sometimes the inferior hilar ligament. It’s not actually a ligament, but an extension of the parietal pleura extending downwards in a fold from the hilum. Some describe it as hanging down from the hilum like a ‘wizard’s sleeve’, which invariably gets a giggle from some of our trainees from the United Kingdom for some reason.

 

After cutting the ligament completely to the level of the inferior pulmonary vein, the lung is then twisted ‘lower lobe towards you’, ie. lower lobe is rotated anteriorly over the upper lobe until the lung is oriented ‘upside down’. The twisted vessels around the hilum become occluded and further haemorrhage from that side should be limited. Other priorities in the arrested patient will be aortic occlusion, internal cardiac massage, and blood products. Packs may be required to keep the lung from untwisting, and if return of spontaneous circulation is achieved, there is a risk of dysrhythmia, right heart failure, and refractory hypoxaemia.

I’ve only done this on pigs and human cadavers so am not speaking from any reassuring level of experience or competence. The literature is out there to read, and it’s up to you to decide how you want to expand or limit your options when you’ve cracked that chest in an arrested patient.

References

1. Flaris AN, Simms ER, Prat N, Reynard F, Caillot J-L, Voiglio EJ. Clamshell incision versus left anterolateral thoracotomy. Which one is faster when performing a resuscitative thoracotomy? The tortoise and the hare revisited. World J Surg. 2015 May;39(5):1306–11.

2. Simms ER, Flaris AN, Franchino X, Thomas MS, Caillot J-L, Voiglio EJ. Bilateral Anterior Thoracotomy (Clamshell Incision) Is the Ideal Emergency Thoracotomy Incision: An Anatomic Study. World J Surg. 2013 Feb 23;37(6):1277–85.

3. Wise D. Emergency thoracotomy: “how to do it.” Emerg Med J. 2005 Jan 1;22(1):22–4.

4. Davies GE, Lockey DJ. Thirteen Survivors of Prehospital Thoracotomy for Penetrating Trauma: A Prehospital Physician-Performed Resuscitation Procedure That Can Yield Good Results. The Journal of Trauma: Injury, Infection, and Critical Care. 2011 May;70(5):E75–8.

5. Wilson A, Wall MJ Jr., Maxson R, Mattox K. The pulmonary hilum twist as a thoracic damage control procedure. The American Journal of Surgery. 2003 Jul;186(1):49–52.

Pre-SMACC mini RAGE

Currently the RAGE Podcast site is recovering from a cold, so here are the show notes for the pre-SMACC mini RAGE episode released June 2015.
Here is the podcast
And here are the references:
SMACC Conference
It’s a knockout

GoodSAM
GoodSAM App
Oxygen therapy
AVOIDthis2
AVOID: Air Versus Oxygen in ST-Segment Elevation Myocardial Infarction.
HOT or NOT trial: HyperOxic Therapy OR NormOxic Therapy after out-of-hospital cardiac arrest (HOT OR NOT): a randomised controlled feasibility trial.
Helicopter Emergency Medical Services
Survival benefit of a physician-staffed HEMS assistance for severely injured patients
Willingness to pay for lives saved by HEMS
Intraosseous access
Intraosseous infusion rates under high pressure: a cadaveric comparison of anatomic sites.
Intraosseous hypertonic saline: myonecrosis in swine
Intraosseous hypertonic saline: safe in swine
Discussion post about intraosseous hypertonic saline at Sydney HEMS
Handstands
Handstands: a treatment for supraventricular tachycardia?
Impact of a modified Valsalva manoeuvre in the termination of paroxysmal supraventricular tachycardia
Handstands keep you awake
 
The next RAGE Podcast will air late August / early September

London Trauma Conference 2014 Part 2

Day three is Air Ambulance and pre-hospital day and the great and the good are here en mass.
The heavy weights are coming out to make their points…..
selfUnarguably the best lecture of the day was delivered by our very own Cliff Reid on prehospital training. Using Sydney HEMS induction training he highlighted the challenges posed to prehospital services training doctors and paramedics rotating through the service.
Turning a good inhospital doctor into a great prehospital one in the space of an induction program requires focus. Knowledge is therefore not the focus of training, performance is. Often doctors already possess the clinical skills and knowledge and it is the application of these pre existing skills in challenging environments when cognitively overloaded that is the key.
 
The Sydney HEMS program provides the mindware and communication skills the practitioner needs to do this and drills these skills in simulated environments. He uses perturbation, so like the Bruce protocol exercise test the simulations just get harder until you are at the very limits of your bandwidth. Debriefing of course is important but the recommended protracted debrief is often impractical and unnecessary so simulations designed with cognitive traps are used to highlight learning points and are drilled until the message is received. In this way tress exposure enhances cognitive resilience. And importantly they use cross training, so the doctors and the paramedics undergo the same program so each member of the team understands the challenges faced by the other.
Does this sound like fun? For the shrinking violets out there it could be seen as threatening. But for the adrenaline junkies…….hell yeah!
It’s truly a training ethos that I buy into and I’d love to be able to achieve that standard of training in my own service.

SydneyHEMStops
Sydney HEMS Friends and Colleagues at the LTC

 
mwaveMicrowaves seem to be the future if diagnostic testing. This modality is fast, is associated with a radiation dose lower than that of a mobile phone, non invasive, portable and has been shown to provide good information. It can be used on heads for intracranial haemorrhage and stroke or chests for pneumothorax detection. It’s all in the early stages but seems like it will be a viable option in the future.
For further reading check out:
Diagnosis of subdural and intraparenchymal intracranial hemorrhage using a microwave-based detector
Clinical trial on subdural detection
Pneumothorax detection
 
How would you transfer a psychotic patient requiring specialist intervention that can only be received after aeromedical transfer? Stefan Mazur of MedSTAR, the retrieval service in South Australia shared their experience with ketamine to facilitate the safe transfer of these patients with no reports of adverse effects on the mental state of the patient, as first described by Minh Le Cong and colleagues. Is there no end to the usefulness of this drug? No wonder we’re experiencing a supply issue in the UK!
And finally, the ultimate reflective practice should include the post mortem of our critically sick patients. The approach the forensic pathologist takes is similar to a clinician (with the time pressure removed). They read the scene and use this information to predict injuries (sound familiar?). Post mortem CT scanning with recon provides yet another layer of information. We are missing a trick if we don’t seek this feedback to correlate with our clinical findings. Even better, rare practical skills are often routinely performed as part of the post mortem – we should be making use of this opportunity to train.

London Trauma Conference Day 3


Dr Louisa Chan reports on Day 3 of the London Trauma Conference
There was a jam-packed line up for the Pre-hospital and Air Ambulance Day which was Co-hosted by the Norwegian Air Ambulance Foundation.
 

My highlights were:

HEMS

Dr Rasmus Hesselfeldt works in Denmark where they have a pretty good EMS system with ambulances, RRV’s and PHC doctors. Road conditions are good with the longest travel distance of 114 miles. So would the introduction of a HEMS service improve outcomes? He did an observational study looking at year of data post-trial and compared this with 5 months pre-trial. Trauma patients with ISS > 15 and medical emergencies greater than 30 min by road to the Trauma Centre (TC). Primary endpoint was time to TC, secondary outcomes were number of secondary transfers and 30 day mortality.
Results: Increase in on scene time 20 min vs 28 min, time to hospital increased but time to TC was less – 218 min vs 90 min, reduced mortality, increased direct transfer to TC and fewer secondary transfers.
Full article here: A helicopter emergency medical service may allow faster access to highly specialised care. Dan Med J. 2013 Jul;60(7):A4647
 
Airway
Prof Dan Davis ran through pre-hospital intubation. It seems that this man has spent his life trying to perfect airway management. Peter Rosen was his mentor and imprinted on him that RSI is the cornerstone of airway management.
So surely pre-hospital intubation saves lives. The evidence however begs to differ, or does it? As with all evidence we need to consider the validity of the results and luckily Prof Davis has spent a lot of time thinking through the reasons why there no evidence.
During his research he opened a huge can of worms:
1. Hyperventilation was common – any EtCO2 <30mmHg lead to a doubling in mortality.
2. First pass intubation is great, but not if you let your patient become hypoxic or hypotension or worse still both!
3. Hospital practice had similar issues.
So really the RSI processes he was looking at weren’t great.
The good news is that things have improved and he can now boast higher first pass rates and lower complication rates for his EMS system. His puts this success down to training.
 
 
AIRPORT-LTCThe AIRPORT study was discussed at last years LTC. This year we have the results. 21 HEMS services in 6 countries were involved in the data collection including GSA HEMS. The headline findings are that intubation success rates are high (98%) with a complication rate of 10-12%. The more difficult airways were seen in the non-trauma group. 28.2% patients died (mainly cardiac arrest).
 
 
Matt Thomas reported on REVIVE – a pre-hospital feasibility study looking at airway management in OHCA (I-Gel vs LMA Supreme vs standard care). It was never powered to show a difference in these groups, the main aim was to see if research in this very challenging area was possible. And the answer is YES. The paramedics involved recruited more patients than expected and stuck to the protocol (prob better that docs would have!). A randomised controlled trial to look at the I-Gel vs ETT is planned.
 
(P)REBOA
ReboaLTCFinally, Pre-hospital Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) seems eminently possible – Dr Nils Petter Oveland showed us the training manikin they developed for training. Through training on this manikin they achieved an average skin to balloon time of 3.3mins. Animal data supports this procedure as a bridge to definitive care in non compressible haemorrhage.
London HEMS will be starting (P)REBOA in the New Year.
So now it’s stand up science, I’m off for my glass of wine…………….
Check out what they’re saying about the London Trauma Conference on Twitter

RSI haemodynamics in the field

intubated-prehosp-vol-iconThe noxious stimulus of laryngoscopy & tracheal intubation can precipitate hypertension, tachycardia, and intracranial pressure elevation, risking exacerbation of brain injury or haemorrhage. Physicians from an English Helicopter Emergency Medical Service examined the response of heart rate and blood pressure to prehospital rapid sequence intubation (RSI). While a retrospective study, the haemodynamic data were prospectively recorded and documented using standard monitor printouts, and time of intubation could be accurately determined by the onset of capnography recordings. Their standardised system documents blood pressure recordings every three minutes. Etomidate and suxamethonium were used for RSI.
They report their findings:


A hypertensive response occurred in 79% (70/89) of patients. MAP exceeded the upper limit of estimated intact cerebral autoregulation (150 mmHg) in 18% (16/89) of cases and 9% (8/89) of patients had a greater than 100% increase in MAP and/or SBP. A single hypotensive response occurred. A tachycardic response occurred in 58% (64/110) of patients and bradycardia was induced in one.

Of note, 97 of the 115 patients had injuries that included head trauma.
The authors note that opioids are often co-administered during in-hospital RSI and that this may offset the haemodynamic stimulation, while possible increasing the complexity of the procedure in the prehospital environment. They have modified their pre-hospital anaesthesia standard operating procedure to include the use of an opioid and will report the associated outcomes and complication rates ‘in due course’.
This is interesting and important stuff, and something we should all be looking at in our respective prehospital critical care services.
The haemodynamic response to pre-hospital RSI in injured patients
Injury. 2013 May;44(5):618-23
[EXPAND Abstract]


BACKGROUND: Laryngoscopy and tracheal intubation provoke a marked sympathetic response, potentially harmful in patients with cerebral or cardiovascular pathology or haemorrhage. Standard pre-hospital rapid sequence induction of anaesthesia (RSI) does not incorporate agents that attenuate this response. It is not known if a clinically significant response occurs following pre-hospital RSI or what proportion of injured patients requiring the intervention are potentially at risk in this setting.

METHODS: We performed a retrospective analysis of 115 consecutive pre-hospital RSI’s performed on trauma patients in a physician-led Helicopter Emergency Medical Service. Primary outcome was the acute haemodynamic response to the procedure. A clinically significant response was defined as a greater than 20% change from baseline recordings during laryngoscopy and intubation.

RESULTS: Laryngoscopy and intubation provoked a hypertensive response in 79% of cases. Almost one-in-ten patients experienced a greater than 100% increase in mean arterial pressure (MAP) and/or systolic blood pressure (SBP). The mean (95% CI) increase in SBP was 41(31-51) mmHg and MAP was 30(23-37) mmHg. Conditions leaving the patient vulnerable to secondary injury from a hypertensive response were common.

CONCLUSIONS: Laryngoscopy and tracheal intubation, following a standard pre-hospital RSI, commonly induced a clinically significant hypertensive response in the trauma patients studied. We believe that, although this technique is effective in securing the pre-hospital trauma airway, it is poor at attenuating adverse physiological effects that may be detrimental in this patient group.

[/EXPAND]

Helicopters and improved trauma survival

A large retrospective study has shown increased trauma survival associated with helicopter transport. The reason is unclear and may be multifactorial: faster speed, greater access to trauma centres, higher exposure of crews to trauma, different crew skill mix and so on are all possibilities.
An interview of less than five minutes with one of the authors describes the study:


Context Helicopter emergency medical services and their possible effect on outcomes for traumatically injured patients remain a subject of debate. Because helicopter services are a limited and expensive resource, a methodologically rigorous investigation of its effectiveness compared with ground emergency medical services is warranted.

Objective To assess the association between the use of helicopter vs ground services and survival among adults with serious traumatic injuries.

Design, Setting, and Participants Retrospective cohort study involving 223 475 patients older than 15 years, having an injury severity score higher than 15, and sustaining blunt or penetrating trauma that required transport to US level I or II trauma centers and whose data were recorded in the 2007-2009 versions of the American College of Surgeons National Trauma Data Bank.

Interventions Transport by helicopter or ground emergency services to level I or level II trauma centres.

Main Outcome Measures Survival to hospital discharge and discharge disposition.

Results A total of 61 909 patients were transported by helicopter and 161 566 patients were transported by ground. Overall, 7813 patients (12.6%) transported by helicopter died compared with 17 775 patients (11%) transported by ground services. Before propensity score matching, patients transported by helicopter to level I and level II trauma centers had higher Injury Severity Scores. In the propensity score–matched multivariable regression model, for patients transported to level I trauma centers, helicopter transport was associated with an improved odds of survival compared with ground transport (odds ratio [OR], 1.16; 95% CI, 1.14-1.17; P < .001; absolute risk reduction [ARR], 1.5%). For patients transported to level II trauma centers, helicopter transport was associated with an improved odds of survival (OR, 1.15; 95% CI, 1.13-1.17; P < .001; ARR, 1.4%). A greater proportion (18.2%) of those transported to level I trauma centers by helicopter were discharged to rehabilitation compared with 12.7% transported by ground services (P < .001), and 9.3% transported by helicopter were discharged to intermediate facilities compared with 6.5% by ground services (P < .001). Fewer patients transported by helicopter left level II trauma centers against medical advice (0.5% vs 1.0%, P < .001).

Conclusion Among patients with major trauma admitted to level I or level II trauma centers, transport by helicopter compared with ground services was associated with improved survival to hospital discharge after controlling for multiple known confounders.


Association Between Helicopter vs Ground Emergency Medical Services and Survival for Adults With Major Trauma

JAMA, April 18, 2012—Vol 307, No. 15 1602-10 Full Text

Body temperature in anaesthetised HEMS patients

This study raises an important issue – how do we keep patients with major trauma warm on the way to hospital? The authors from HEMS London identified mean temperatures in hospital of 35°C in patients who had been anaesthetised in the field, although only 38% of their patients had a temperature recorded on admission!
I emailed the author Audun Langhelle for practical information on the thermal protection package they use, who was most helpful in supplying the following information. Clicking on the link will take you to online supplements to the paper describing and illustrating their technique of prehospital rewarming.

Hi Cliff,

Thank you for your request and interest in our paper. Now fully repatriated to Norway, we’re currently using the medium sized UniqueResc warming blanket (Geratherm, Germany) at my base, together with the bubble wrap. In Norway, Garatherm is the only company which has been able to provide us with the necessary paper work showing that their product complies with the rather strict pan European rules and regulations, the EN 13718-1: Requirements for medical devices used in air ambulances in particular.
Working as HEMS doc with LAA 2008-2009, we played with and introduced the policy using Diemme’s (Italy)DM EMG >> http://emj.bmj.com/content/early/2010/10/19/emj.2009.086967/suppl/DC1, but I’m not sure what blanket they currently use.

Kind regards,

Audun

We reviewed this article in one of our Sydney HEMS Clinical Governance Days last year. One of our team presented a critical appraisal and if you’re interested the deadly PowerPoint slides are here:


Background Hypothermia at hospital admission has been found to independently predict increased mortality in trauma patients.

Objectives To establish if patients anaesthetised in the prehospital phase of care had a higher rate of hypothermia than non-anaesthetised patients on admission to hospital.

Methods Retrospective review of admission body temperature in 1292 consecutive prehospital trauma patients attended by a physician-led prehospital trauma service admitted to The Royal London Hospital between 1 July 2005 and 31 December 2008.

Results 38% had a temperature recorded on admission. There was a significant difference in body temperature between the anaesthetised group (N=207) and the non-anaesthetised group (N=287): mean (SD) 35.0 (2.1) vs 36.2 (1.0)°C, respectively (p <0.001). No significant seasonal body temperature variation was demonstrated.
Conclusion This study confirmed that patients anaesthetised in the prehospital phase of care had a significantly lower admission body temperature. This has led to a change in the author’s prehospital practice. Anaesthetised patients are now actively surface heated and have whole body insulation to prevent further heat loss in an attempt to conserve body temperature and improve outcome. This is an example of best in-hospital anaesthetic practice being carried out in the prehospital phase.

Body temperature of trauma patients on admission to hospital: a comparison of anaesthetised and non-anaesthetised patients
Emerg Med J. 2012 Mar;29(3):239-42
Full text link

Utstein-like template for physician EMS

Many European and Australasian emergency medical services deploy physicians to the scene. In order to facilitate consistent data reporting and future collaborative research, a working group produced a recommended reporting template. The group consisted of ‘sixteen European experts in the field of pre-hospital care’, and the nine authors of the study were seven Scandinavians, one Italian and one Brit.

Prehospital Care Doctors
They established an Utstein-like template for documenting and reporting in physician-staffed pre-hospital services. The core data set consists of 45 variables grouped in five different categories: “fixed system variables”, “event operational descriptors”, ” patient descriptors”, “process mapping”, and “outcome measures and quality indicators”.

A consensus-based template for documenting and reporting in physician-staffed pre-hospital services
Andreas J Kruger, David Lockey, Jouni Kurola, Stefano Di Bartolomeo, Maaret Castren, Soren Mikkelsen, Hans Morten Lossius
Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine 2011, 19:71 Full Text
Full text PDF

Pre-hospital thoracotomy

The London Helicopter Emergency Medical Service provides a physician / paramedic team to victims of trauma. One of the interventions performed by their physicians is pre-hospital resuscitative thoracotomy to patients with cardiac arrest due to penetrating thoracic trauma. They have published the outcomes from this procedure over a 15 year period which show an 18% survival to discharge rate, with a high rate of neurologically intact survivors1.
The article was submitted for publication on February 1, 2010, and in the discussion mentions a further two survivors from the procedure performed after conducting the study. It is likely therefore in the year and a half since submission still more patients have been saved. It will be interesting to read future reports from this team as the numbers accumulate; penetrating trauma missions are sadly increasing in frequency.
Having worked for these guys and performed this procedure in the field a few times myself, I can attest to the training and governance surrounding this system. The technique of clamshell thoracotomy is well described 2 and one I would recommend for the non-surgeon.

BACKGROUND: Prehospital cardiac arrest associated with trauma almost always results in death. A case of survival after prehospital thoracotomy was published in 1994 and several others have followed. This article describes the result of prehospital thoracotomy in a physician-led system for patients with stab wounds to the chest who suffered cardiac arrest on scene.
METHODS: A 15-year retrospective prehospital trauma database review identified victims of stab wounds to the chest who suffered cardiac arrest on scene and had thoracotomy performed according to local standard operating procedures.
RESULTS: Overall, 71 patients met inclusion criteria. Thirteen patients (18%) survived to hospital discharge. Neurologic outcome was good in 11 patients and poor in 2. Presenting cardiac rhythm was asystole in four patients, pulseless electrical activity in five, and unrecorded in the remaining four. All survivors had cardiac tamponade. The medical team was present at the time of cardiac arrest for six survivors (good neurologic outcome): arrived in the first 5 minutes after arrest in three patients (all good neurologic outcome), arrived 5 minutes to 10 minutes after arrest in two patients (one poor neurologic outcome), and in one patient (poor neurologic outcome) the period was unknown. Of the survivors, seven thoracotomies were performed by emergency physicians and six by anesthesiologists.
CONCLUSIONS: Prehospital thoracotomy is a well-established procedure in this physician-led prehospital service. Results from this and other similar systems suggest that when performed for the subgroup of patients described, significant numbers of survivors with good neurologic outcome can be expected.

1. Thirteen Survivors of Prehospital Thoracotomy for Penetrating Trauma: A Prehospital Physician-Performed Resuscitation Procedure That Can Yield Good Results
J Trauma. 2011 May;70(5):E75-8
2. Emergency thoracotomy: “how to do it”
Emerg Med J. 2005 January; 22(1):22–24
Full text available here