Monday, March 30, 2020

Clinical Use of Ultrasound at a High Altitude Clinic in Nepal

Bryan Jarrett, M.D. 
Wilderness Medicine Fellow, 
Massachusetts General Hospital Department of Emergency Medicine

Performing a right upper quadrant ultrasound to evaluate for
biliary pathology 
Bedside ultrasound in the emergency department has become a standard supplement to traditional imaging such as x-rays and CT. It is now becoming a primary imaging modality when these more traditional methods are unavailable, especially as we realize the breadth of pathologies ultrasound can diagnose. I recently returned from three months working at a clinic in a remote region of Nepal run by the Himalayan Rescue Association. Pheriche is a small town which sits at approximately 14,000 ft altitude on the trek into the Khumbu valley to Everest Base Camp, and sees approximately 600 to 800 patients each Spring and Fall season. The closest small hospital is in Kunde, a town north of Namche approximately one or two day’s walk away, and has x-ray and ultrasound capabilities. The closest CT scanner is in Kathmandu, a few hours by helicopter or 4 days of hiking and a plane flight away.

I had the privilege of bringing along a Sonosite M Turbo ultrasound provided by their global health division as well as the new ultra-portable Butterfly IQ handheld ultrasound. Through the use of these ultrasounds, I was able to greatly improve clinical care and diagnostic certainty in this remote clinic without access to other imaging modalities.
Lung ultrasound is a very sensitive modality
to detect interstitial pulmonary, such as that
seen in high altitude pulmonary edema (HAPE)

Over the course of the spring 2019 season I performed 83 clinical ultrasounds on 75 patients, which represented 14.4% of our total number of patients. Thirteen of these ultrasounds changed management, 2 improved procedures, and 48 improved diagnostic certainty by providing a useful positive or negative result. The most common ultrasounds performed were pulmonary or lung studies, as more than 30 percent of our patients had respiratory tract infections. Other common modalities included cardiac echocardiograms, obstetric, musculoskeletal, and abdominal ultrasound. As an advocate for training in and access to this incredibly useful diagnostic tool, it was amazing to observe its benefits in a remote environment where it really shines.

Patient with peritonsillar abscess receiving nebulized
lidocaine before drainage guided by ultrasound imaging
before and afterwards. 
One interesting case in which ultrasound proved useful was in a young man who came in with unilateral throat pain. He had what clinically appeared to be a peritonsillar abscess which usually requires either needle aspiration or incision and drainage. The major risk of this procedure is damage to the carotid artery which lies behind the tonsils, sometimes perilously close within a centimeter or two. Thanks to the small linear probe covered in a sterile glove, we were able to visualize the abscess as well as the carotid, and assure that our drainage would stay well away from this critical vessel. Granted, an experience ear, nose, and throat surgeon would usually do this without ultrasound guidance, but they would also have the close back-up of a nearby operating room if anything were to go wrong, a contingency we did not have. Ultrasound in this case made this procedure much safer for the patient and much more comfortable for the providers, and we were able to confirm afterwards with repeat imaging that we had removed as much as possible from the abscess. He felt significantly better after draining 17 cc of purulent material and happily continued towards Everest Base Camp the following day.

High Altitude Medicine - Caring for locals and trekkers at 14,000 feet in Pheriche, Nepal

Bryan Jarrett, M.D. 
Wilderness Medicine Fellow, 
Massachusetts General Hospital Department of Emergency Medicine

The Himalayan Rescue Association Clinic in
Pheriche with Anna Dablam in the background
Three months above 14,000ft at a high altitude clinic 10 km away from Everest Base camp taking care of trekkers and the local Nepali population, armed only with my stethoscope, an ultrasound, and my clinical training… sign me up. My name is Bryan Jarrett, and I am a Wilderness Medicine Fellow at Massachusetts General Hospital. Our specialty focuses on providing care in resource-limited and remote environments, and this certainly qualified.

The Himalayan Rescue Association has been providing care in the Khumbu region since the 1970s. Their first and longest operating clinic is in the town of Pheriche, a stop on the trek to Everest Base camp and multiple other locations, done by approximately 25-30,000 international visitors each season (the trekking seasons are in the Fall and Spring). In order to support these trekkers, a large number of Nepali lodge workers and porters migrate seasonally to these high altitude communities during these times. By the end of almost two and a half months of clinical work, our team of three physicians and a Nepali medic named Thaneshwar had taken care of almost 700 patients and evacuated 27 people by helicopter for severe illnesses.

The majority of our patients were Nepali (70%), and the most common diagnoses we saw were upper respiratory tract infections (33.6%), followed closely by acute mountain sickness (8.6%), gastroenteritis (8.3%), and musculoskeletal complaints (6.2%),
Helicopter evacuation of a critical patient after a large snowstorm 
making this experience just as much international primary care as it was high altitude medicine. Our interesting cases were a good mix of typical emergency medicine cases presenting in this austere environment as well as a large number of the two severe forms of altitude illness, high altitude pulmonary edema (HAPE) and high altitude cerebral edema (HACE).

High altitude pulmonary edema is the more common of these two, resulting in interstitial fluid in the lungs causing shortness of breath at rest, and in its most severe form, significant hypoxia and possibly death. We had 22 cases of HAPE, of which the majority were Nepali, and we evacuated 13 of these by helicopter down to Lukla approximately 5000 ft below Pheriche, or usually all the way down to Kathmandu. A normal oxygen saturation at 14,000 ft is approximately 80-90%, but most of our patients with HAPE presented with saturations in the 50’s with significant shortness of breath. The mainstay of our treatment was supplemental oxygen via oxygen concentrators which we ran off of power supplied from solar panels, and most patients improved on oxygen and nifedipine, a medicine to decrease the blood pressure in the lungs. Thankfully, all patients we saw were able to either ride a horse or helicopter down to lower altitudes for a safe recovery.

Fewer patients presented with high altitude cerebral edema, a condition in which the brain swells at high altitude causing confusion and difficulty walking. All but one of these six patients were evacuated by helicopter after treatment with oxygen and dexamethasone, a steroid shown to be helpful in improving this swelling. Many of these patients came in being carried by friends, horses, or porters; confused, and unable to walk on their own.
 A patient with HAPE, with a normal saturation 

on supplemental oxygen, with ultrasound images 
of B-Lines representing the Interstitial edema in 
his lungs

There are very few places where one can treat young, otherwise healthy patients with acute, potentially deadly conditions and watch them improve over 12 to 24 hours with treatment. This was a truly special aspect of this experience. While providing care for these unique pathologies only found with this prevalence in a few locations around the globe was invaluable, the true joy was providing medical care to the local population. This was less glamorous, and provided less excitement, but ultimately greater satisfaction. We were able to repair significant lacerations, give antibiotics to respiratory and skin infections, and treat basic aches and pains. I will never forget the beautiful mountains, the young patients who are still alive because we were there to provide them with much-needed care, and the friends I made in the process.