Wilderness & Environmental Medicine最新文献

Introduction: The sharpened Romberg test (SRT) is a physical maneuver that has been used to identify ataxia in individuals in resource-limited settings. Previous research has suggested that performance on balance testing may be affected by hypocapnia. In this study, we sought to determine whether acute hyperventilation-induced hypocapnia affects performance on the SRT at 501 meters above sea level.

Methods: We recruited 22 healthy subjects. Each subject performed a baseline SRT. Subjects were then asked to hyperventilate to the point of hypocapnia, confirmed by measurement with a capnometer. Subjects were then asked to re-perform SRT. The primary endpoint was time to loss of balance, measured as time-to-stepout.

Results: Time-to-stepout (TTS) on SRT at baseline had a mean ± standard deviation of 101 ± 117 s. In the hypocapnic condition, TTS was reduced to 48 ± 68 s. TTS normalized to 121 ± 132 s after recovery to normal capnic levels. Time-to-stepout was found to be significantly shorter in the hypocapnic measurement compared to the baseline measurement (P = .0128). Statistical analysis was conducted using one-tailed, paired sample T-tests using a P-value of < .05.

Conclusions: Our study found a statistically and clinically significant reduction in performance on a balance test (SRT) when exposed to acute hyperventilation-induced hypocapnia compared to a eucapnic control. Our results suggest that acute hypocapnia may contribute to neurological dysfunction independently of hypobaric hypoxia.

Dr William J. Mills Jr., an Alaskan orthopedic surgeon, helped establish the current protocols for frostbite treatment and changed a dogma used for more than 140 years that was established by Napoleon's surgeon general of the army, Baron Dominique-Jean Larrey. During Napoleon's 1812 siege of Moscow, Larrey noticed the destructive effects of using open fire heat for warming frozen body parts, so he suggested rubbing snow or immersion in cold water. Dr Mills treated many cold injuries during his medical career. After setting up his medical practice in Anchorage, Alaska, he realized the inefficiency of the established protocols and started researching new treatments for frostbite. Dr Mills followed Meryman's method of rapidly thawing frozen red blood cells in warm water. Mills and his colleagues established a treatment protocol for freezing cold injury that included rapid warming in warm water. These studies resulted in the publication of three key papers in 1960 and 1961. These papers were the first clinical studies that described rapid warming as a treatment. Subsequently, rapid warming, with some variation in water temperatures, has been accepted as the standard of treatment. Due to his outstanding contribution to the treatment of frostbite, he has been referred to as "the nation's leading authority on cold injury." Mills and his colleagues created a new classification system that divided frostbite into two levels, superficial and deep, which was more applicable in clinics than the traditional 4-tier classification. The 2-tier classification is still useful outside of the hospital setting.

We describe a case of severe accidental hypothermia of a kayaker with preserved consciousness and shivering despite a rectal temperature of 22.9°C following a 50-min immersion in 3°C water with an estimated core temperature cooling rate of 10.6°C/h. Based on survival at sea prediction curves and cooling rates from physiology studies, cold water (eg, 0-5°C) immersion is expected to drop core temperature by 2 to 4°C/h. Furthermore, accidental hypothermia classification systems predict that severely hypothermic patients are usually unconscious and not shivering. The patient in this report rewarmed rapidly at 3.6°C/h with only minimally invasive measures and was discharged fully neurologically intact. In 41 similar cases of survival in moderate to severe hypothermia with core temperatures <32°C due to cold water immersion, cold air exposure, or avalanche burial, mean cooling rates were 4.3±3.3°C/h (range 0.4-10.6°C/h). Including the current patient, shivering was reported in only four cases. We found several other cases of rewarming from moderate to severe hypothermia with only minimally invasive measures. The current and summarized cases lead us to conclude that patients may be at risk of severe hypothermia in <60 min of cold water immersion and that it is possible for severely hypothermic patients to have preserved consciousness, close to normal vital signs, and shivering. Minimally invasive or noninvasive rewarming of patients with severe hypothermia is also possible, especially in those who continue to shiver. Hypothermia management should not necessarily be guided by classification systems or core temperature alone but rather by a careful consideration of the entire clinical picture.

Introduction: Although many backcountry first aid kits contain antibiotic ointment, the supply can be quickly exhausted if a patient has extensive wounds or if there are multiple patients.

Methods: We assessed the antibacterial properties of bark extract from four North American woody plant species known to native Missourians as medicinal plants (Quercus macrocarpa, Salix humilis, Pinus echinata, and Hamamelis vernalis). We tested their antimicrobial properties, with the disc diffusion technique, against four common pathogenic bacterial species: Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Enterobacter aerogenes (now known as Klebsiella aerogenes).

Results: We report evidence of antibacterial activity of bark extract from all four plant species.

Conclusions: Our results confirm that traditional uses of these species may be useful in fighting infection and could be especially useful in a wilderness setting when modern antibiotics are exhausted.

A man attacked by a pet zebra suffers multiple bite wounds to his right arm and generalized trauma after being dragged to the ground and pinned by the animal. He was transported to the emergency department (ED) by the local emergency medical service (EMS) with a tourniquet in place for nearly 60 min. The man's injuries included extensive soft tissue damage, an open fracture and dislocation of his right elbow, and a soft tissue injury to his right ear. His clinical course was complicated by severe necrosis of the soft tissue of the right forearm requiring transhumeral amputation just above the condyles. Ongoing infection and the development of phantom limb pain complicated his recovery.

Catfish are a highly diverse group of fish comprising more than 3500 species found in both freshwater and marine ecosystems. Upon handling, they can inflict a sting, with certain species capable of inducing significant pain and injury to the affected extremity. The prevalence of aquatic activities, such as fishing by line or manual capture ("noodling"), increases the likelihood of catfish stings, making prompt identification and treatment an important aspect of managing such encounters. A case of a presumed catfish spine injury during noodling in Tallahassee, Florida, is presented. The pectoral fin penetrated the volar aspect of the patient's right hand resulting in immediate pain and numbness. Over the course of 2 weeks, the patient developed distal ulnar neuropathy with conduction block at the wrist level. Surgical exploration revealed the ulnar nerve to be grossly intact, but the area surrounding the terminal division point of the ulnar nerve in the hand displayed infiltration by fibrous tissue that entrapped the nerve and its branches. Following surgical release of the ulnar nerve and its terminal branches from the fibrous tissue, complete resolution of distal ulnar neuropathy was achieved. In this patient's case, the absence of foreign bodies and the lack of visible nerve damage suggest that the injury to the patient's hand was largely attributable to toxin-mediated proinflammatory response and fibrosis.