Letter from America: Early Cooling Crossing the Atlantic

Rob Lawrence is chief operating officer of the Richmond Ambulance Authority. Before coming to the USA, he held the same position with the English county of Suffolk as part of the East of England Ambulance Service. He writes a regular "Letter from America" column for the UK publication Ambulance Life. This column is reprinted with permission from Ambulance Life.

It’s always good to report on the cool things going on in the ambulance world and get to the heart of matters; and this article does exactly what it says on the tin.

I was delighted to read that London’s HEMS has become the first agency in the UK to trial the use of RhinoChill on cardiac arrest patients. The benefit of therapeutic hypothermia (TH) initiated after hospital arrival in out-of-hospital cardiac arrest patients whose initial rhythm is ventricular fibrillation is documented solidly in two large, randomized trials.

Less well proven, but provided increasingly in the USA, is the initiation of prehospital cooling by paramedics either following return of spontaneous circulation (ROSC) or during ongoing resuscitation in an effort to reduce cellular metabolism and reduce reperfusion injury.

TH has been employed in Richmond since 2004 and the success rates because of it, particularly in terms cerebrally intact patients emerging from the hospital, are increasing.

Our cooling journey over the last few years has been one of research and discovery as our work has been directed and overseen by our Medical Director Dr. Joseph P Ornato. "Dr O," as he is affectionately known to our medics, is also professor and chair of the Department of Emergency Medicine at Virginia Commonwealth University Medical Center. He is an internationally renowned and very well published cardiologist, and he is one of the reasons I wanted to work here at RAA.

Against that academic backdrop, Richmond’s preferred method of administration is to infuse up to 1500ml of iced saline via intraosseous (IO) drill into the humerus during ongoing resuscitation, rapidly lowering the patient’s temperature to approximately 95ºF, often before ROSC is even achieved.

A RAA Field Operations Supervisor attends every arrest to provide clinical management and administer the cooled solution, using our Richmond Induced Cooling by EMS (RICE) protocol. Concurrently, mechanical CPR (in our case the ZOLL AutoPulse system) is also initiated, thereby maintaining continuous compressions, freeing the human hands to continue with the multitude of other essential tasks associated with lifesaving.

One advantage of using such a device is that we don’t have to interrupt chest compressions to defibrillate or insert an advanced airway. As an aside, the debate continues over the effectiveness of mechanical CPR. The recent ZOLL-sponsored Circulation Improving Resuscitation Care (CIRC) Trial concluded in January 2011. Conducted by Dr Lars Wik of Norway’s National Competence Center of Emergency Medicine, Oslo University Hospital, in Oslo, Norway, the trial found that mechanical CPR equaled the bext manually delivered CPR. So it was a draw, well not quite, because countless academic papers point to the diminishing human return in the delivery of quality CPR as time on the patient’s chest goes on.

RAA did not participate in this trial because our own published quality mprovement data showed improved survival after we deployed the AutoPulse in our EMS system. We felt it would have been unethical to have randomized patients in our system given the improvement we had documented.

Returning to our part of the (adult) chain of survival, our current resuscitation strategy relies on a triumvirate of rapid response, immediate and consistent CPR, and experienced delivery of effective

advanced life support. I’m delighted to say, in the main, the street phase of the clinical episode concludes with a patient in ROSC (we hover in the 50th percentile of the Utstein template measure), temperature dropping and an opportunity to reach the location, for which the American Heart Association (AHA) added a new, fifth, link to the chain, that of integrated post-cardiac arrest care.

The latest link, also added by a Richmond based cardiologist, Dr Mary Ann Peberdy, sees our patient arriving at the hospital where cooling continues using a computer-controlled endovascular cooling system, allowing the brain to reach and maintain (typically for 24 hours) a “target” temperature of 92ºF–93ºF. There the warming process is critical to minimize reperfusion injury and is controlled precisely by the endovascular cooling system.

In the final analysis, RAA’s cooling program, followed by sophisticated post-resuscitation care, has allowed the discharge of over 11.9% of these aggressively cooled out-of-hospital cardiac arrest patients neurologically intact (not to be confused with the half of the patients that make it to the front door of the ED). This survival and recovery rate, compared to the US national average of approximately 7.9%, is a small step in the right direction of a journey that must be undertaken.

Until next time, this Trans Atlantic note was brought to you by the letters T and H, and I for one applaud the cool efforts of HEMS.

Rob Lawrence is chief operating officer of the Richmond Ambulance Authority. Before coming to the USA three years ago to work with RAA, he held the same position with the English county of Suffolk as part of the East of England Ambulance Service. He is a graduate of the Royal Military Academy Sandhurst and served in the Royal Army Medical Corps. After a 22-year military career in many prehospital and evacuation leadership roles, Rob Joined the National Health Service, initially as the Commissioner of Ambulance Services in the East of England. He later served with the East Anglian Ambulance Service as director of operations.