Incident Insight reprinted from Alert Diver magazine
By Jocelyn Boisvert CHT Dr Richard Belley MD Dr Julien Poitras MD and Dr Guillaume Lord MD
Portable Hyperbaric Chamber Successfully Treats Divers in Remote Location
>In August 2010, at Les Escoumins in the province of Québec, Canada, two separate occurrences of decompression illness (DCI) took place within one week. One might say "OK, so what - diving emergencies take place all over the world, why are these cases so special?" Well, they were the first fully-documented sport diving DCI treatments in a portable hyperbaric chamber in a public hospital environment in Canada.
>There are two public hyperbaric centers in Québec: Sacré Coeur Hospital in Montréal and the CHAU Hôtel-Dieu de Lévis in Lévis. The Quebec Diving Medical Center (CMPQ) has been in service since 2004. On average, we receive 250 calls a year, of which 30 percent are emergencies. The CMPQ offers both an online and an on-call hyperbaric and diving response physician 24 hours a day, every day. We cover the province of Québec, but we will often help divers from our neighboring provinces as well.
>Les Escoumins is roughly 188 miles away from the nearest hyperbaric chamber. The remote nature of this location makes the management of a DCI case more difficult as there are bound to be treatment delays. In addition, the road from there peaks at about 2,400 feet above sea level. The remote location prompted the acquisition of a portable hyperbaric chamber. The purchase of an SOS Hyperlite in May of 2008 was made possible by the charitable donations of the local diving community and businesses. It was installed at the Health Care Center of Les Escoumins, offering a new option for treating diving emergencies within our provincial protocols.
>At 1:35 p.m., on August 22, 2010, our on-call physician was reached by the emergency physician at Les Escoumins. He inquired about the possibility of an arterial gas embolism (AGE) for a diver who had made a rapid ascent from 40 feet. His bottom time was only 33 minutes, which is normally a no-decompression dive. However, the diver had lost control of his buoyancy during the dive and made an uncontrolled ascent to the surface. Upon reaching the surface, he complained of a headache and elbow pain. Oxygen first aid was administered at the dive site and the diver was transported to the Health Care Center at Les Escoumins. On arrival, he was seen immediately by the emergency physician. Because of the severity of the symptoms and the possibility of an AGE*, the emergency physician contacted our hyperbaric physician. After consultation, they decided to treat the diver in the portable hyperbaric stretcher.
>Note: Symptom onset time and likely etiology (rapid ascent) point toward AGE as a possible mechanism of injury. However, symptom location and character, especially elbow pain, are more consistent with decompression sickness (DCS).
>The portable hyperbaric stretcher is a single person transportable and collapsible hyperbaric chamber; it is seven feet long with a diameter of 24 inches. The chamber can be pressurized to 3 ATA (atmospheres absolute), which enables a US Navy Treatment Table 6, definitive treatment of decompression injuries. Hyperlites are pressurized with air from a standard scuba tank and oxygen is administered by a demand valve. To facilitate communication and patient monitoring, the "doors" at each end are made of clear acrylic. A medical lock is also present which enables delivery of small objects, liquid, food or medications to the injured diver. These chambers are currently used around the world and are approved by Health Canada, a counterpart of the U.S. Food and Drug Administration, for use as a medical device.
>The diver was pressurized to 2.8 ATA within 30 minutes of his arrival and reported complete relief of symptoms within 20 minutes at pressure. The treatment was completed without incident and the diver experienced full and sustained resolution of his symptoms. He was reevaluated after his treatment, was seen again the next day and released from the hospital.
>The medical management of DCI in remote locations may alter the treatment approach. Issues like transportation time, evacuation risk, weather and patient condition all factor into the ultimate decisions about how care is provided. An added concern was the inability to perform a chest x-ray to rule out significant pulmonary barotrauma. Under these circumstances, the relative importance of this test appeared negligible, based on clinical impression.
>In this case, the patient's condition, transportation distance, weather and ascent to altitude were all factors that pointed the treatment team towards local management in the Hyperlite. While one could argue that more conservative measures like surface level oxygen and IV fluids may have been sufficient, weather and evacuation delays made the prospect of potential worsening of symptoms in this remote location the deciding factor.
>On August 26, 2010, the CMPQ received another call from a diver at Les Escoumins complaining of hearing bubbles in his neck one hour after surfacing from two dives (the second dive being deeper than the first one). He mentioned that he had never felt that way before and that he was not feeling good. Our on-call hyperbaric physician decided to send the diver to the local health care center. The hyperbaric physician contacted the emergency physician at Les Escoumins and as soon as the diver reported to the health care center, 100 percent oxygen was administered followed by a full medical evaluation. During the evaluation, some red spots were observed on the diver's neck, but it was not fully clear at that time whether the signs and symptoms reported by the diver were related to the dive.
>Based on the lack of non-diving related explanations, DCS was the presumed diagnosis and the patient was placed in the chamber and pressurized. Soon after reaching the treatment depth of 2.8 ATA, the patient reported some symptom relief and a full US Navy Treatment Table 6 was carried out. There were no complications with the treatment and the patient achieved complete symptom resolution. He was re-evaluated post treatment and was released from the hospital the following day. He was seen again by our hyperbaric physician a couple of days later and did not present any remaining symptoms from his DCS. The diagnosis of DCI is largely based on medical and dive histories. In this case, the diagnosis was uncertain, but local facilities enabled a reasoned approach to this patient and accomplished complete symptom resolution without incurring the costs and risks of evacuation. This patient received the standard of care (for DCI) in a timely manner – the primary goal of all medical treatments.
>In both cases, the rapid initiation of treatment following symptom onset, appeared to expedite symptom resolution. While current clinical data suggests that treatment delays of several hours are not associated with worse outcomes, the remoteness of these locations makes evaluation in a hospital setting an unrealistic requirement. As such, we believe that the responsible use of portable chambers, to include involvement of diving physicians, enables safe and timely treatment of injured divers in our unique settings.