>What types of chambers exist for the treatment of divers?
>Tom Workman: As described by the National Fire Protection Association (NFPA), there are three primary classifications for chambers: Class A, B and C. All chambers must satisfy stringent design and manufacturing criteria established by the American Society of Mechanical Engineers (ASME) Pressure Vessels for Human Occupancy (PVHO) Technical Committee. Accredited health-care facilities provide hyperbaric medical care for clinical conditions that are approved by the Food and Drug Administration (FDA), the Undersea and Hyperbaric Medical Society (UHMS) and the Centers for Medicare and Medicaid Services (CMS).
>Class A, or multiplace, chambers come in various sizes, accommodate multiple patients and have attendant staff within the chamber. Multiplace chambers are pressurized with air, and patients are fitted with a clear plastic hood or face mask that delivers oxygen. With proper staff training, multiplace chambers enable the treatment of all approved hyperbaric indications, including DCI.
Class B, or monoplace, chambers are intended for the treatment of one patient at a time. These chambers make up the majority of chambers in the United States. Class B chambers are usually pressurized with 100 percent oxygen and with properly trained staff can also be used to treat all approved clinical indications, including DCI.
>Monoplace, or class B, chambers are filled with 100 percent oxygen and accommodate a single patient.
>Class C chambers are for animals and are not used to treat people.
>Transportable hyperbaric chambers are those that enable movement of a patient between facilities. These may be small Class B or more portable Class A chambers. A well-known manufacturer of these units is SOS Hyperlite. These single-person chambers enable emergent treatment and potential transportation of divers, but for practical reasons they are not ideal for other clinical applications or repeat treatments.
>In recent years the market has seen an increase in the sale of "mild" or "soft" chambers that are commonly sold to health spas and to individuals for use in their homes. These fabric chambers are limited by the FDA to pressurization with air (rather than oxygen) and are FDA approved only for the treatment of acute mountain sickness. Their use is not approved for any hyperbaric clinical indications, and they do not comply with any of the recognized safety regulations for hyperbaric chambers.
>Is any type of chamber better than others for treating divers?
>Workman: All approved Class A and B chambers that function in an appropriate health-care setting with trained staff can treat dive injuries with equal effectiveness. While large multiplace chambers may be more comfortable for prolonged treatment, they are no more effective in treating DCI or any other approved hyperbaric indication than smaller monoplace chambers.
>Matthew Partrick: When treating DCI in remote locations, patient selection is of the utmost importance. Due to limited resources, it may not always be practical to treat every patient with signs and symptoms of decompression sickness (DCS) with definitive therapy such as portable hyperbaric oxygen (PHBO) chambers or in-water recompression (IWR). A three-tiered triage system can be useful in deciding which patients would most benefit from recompression versus conservative management. Tier 1 patients have mild disease, Tier 2 patients have more moderate symptoms, and Tier 3 patients have life-threatening DCI.
>Patients with mild symptoms, including mild joint pain or rash consistent with "skin bends," are common. Because of the benign nature of Tier 1 patients, it may be reasonable to manage these cases conservatively by administering 100 percent surface oxygen, intravenous hydration and oral nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or ketorolac. More definitive therapy may not be required as the natural progression in these cases is toward improvement, but patients must be carefully monitored for progressive signs or symptoms with serial neurologic exams.
>Tier 3 patients are those with life-threatening DCI, either severe Type II spinal cord DCS, cardiovascular DCS or arterial gas embolism (AGE) with altered mental status or cardiac arrest. Advanced cardiac life support may be life-saving and would take precedence over hyperbaric therapy. These patients are too sick to go back in the water for a trial of IWR and too sick to be put in a small portable hyperbaric chamber where team members would be unable to intervene without decompressing the chamber.
>Regardless of patient selection, treatment of DCS in remote locations with either IWR or PHBO chambers requires significant training, equipment and experience. All patients should receive 100 percent oxygen, intravenous fluids and possibly NSAID therapy. Those who have more significant disease should be considered for recompression therapy. The logistical and financial difficulties associated with both IWR and PHBO can be challenging but are not insurmountable.
>What is the state of hyperbaric chamber access for injured divers in the United States today?
>Chamber operators can communicate with patients or inside tenders
>while operating multiplace, or class A, chambers.
>while operating multiplace, or class A, chambers.
>Dick Clarke: In the setting of acute-onset decompression accidents, immediate availability of hyperbaric treatment is imperative; it can literally mean the difference between life and death. Immediate chamber access can lead to the resolution of a devastating spinal cord injury that might otherwise leave a diver permanently disabled; it may allow a diver to continue to enjoy the underwater world rather than be medically restricted from further diving.
>While the preceding statements are generally well appreciated, divers are reminded of them because of a serious threat to the availability of care. In fact, this threat has evolved to the point of crisis. On an increasingly frequent basis, hospitals that have long been available to treat divers regardless of when an accident occurs are severely restricting chamber access or closing their hyperbaric facilities altogether. In the past several months alone two such treatment facilities in Florida advised DAN® to look elsewhere for emergency care of injured divers.
>What is driving such an unconscionable loss of emergent access? As paradoxical as it seems, it is occurring during a period of unprecedented growth in the availability of hyperbaric medicine across the United States. The explanation is found in the business model driving this growth. To maximize revenue generation while at the same time greatly reducing costs, essentially all this new growth is limited to the use of hyperbaric treatment chambers for outpatients with chronic wound-healing problems. Acutely ill patients for whom hyperbaric treatments have long represented a vital standard of care are now, in many cases, out of luck.
>So why is this growth in hyperbaric medicine causing long-standing 24/7 facilities either to stop providing urgent care or close altogether? In a word, it's money, or an increasing lack of it. As hyperbaric programs open with these new business models, they compete with existing programs for the same pool of well-insured outpatients, those who are clinically easy to manage. This reduces revenue generation at the 24/7 facilities, while the costs of care continue to increase.
>Given that this crisis is based largely upon revenue shortfalls, efforts are under way to alter how hospitals are paid for the provision of hyperbaric medicine. It would seem reasonable that the greatly increased costs of providing emergent 24/7 care (e.g., more highly trained health-care practitioners, ancillary equipment requirements, on-call fees for physicians and staff) should be considered within the health insurance payment process.
>It is traditionally difficult to convince insurance companies to pay higher fees, but we at the Baromedical Research Foundation suggest that non-24/7 outpatient-only programs have their payments reduced by a modest amount, passing on these savings to 24/7 programs. This would represent a revenue-neutral process. As there are many more non-24/7 programs than 24/7 programs, the proposed modest reduction could mean a significant revenue increase to those facilities providing 24/7 care. It might even be sufficiently rewarding that those facilities that have stopped providing 24/7 care might reconsider their decision.
>Fortunately for divers, DAN keeps track of the availability of chambers around the world. If you have symptoms after diving, avoid confusion and call the DAN Emergency Hotline (+1-919-684-9111).
>Dick Clarke, CHT, is the president of National Baromedical Services and the National Board of Diving and Hyperbaric Medical Technology. He also directs the Baromedical Research Foundation, a nonprofit organization dedicated to the scientific advancement of hyperbaric medicine. Clarke has taught diving and hyperbaric medicine since 1976.
>Meet the Experts
>Matthew S. Partrick, M.D., is board certified in emergency medicine and diving and hyperbaric medicine and completed a hyperbaric medicine fellowship at the University of Pennsylvania. He is the medical director at the Institute for Diving Medicine in Ocean County, N.J.
>W.T. "Tom" Workman, MS, CAsP, CHT, FAsMA, is the director of Quality Assurance and Regulatory Affairs for the Undersea and Hyperbaric Medical Society (UHMS). Workman is the principal architect of the UHMS chamber facility accreditation program and the leading expert on chamber safety.
>© Alert Diver — Summer 2011