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CHAPTER 132: Diving Medicine and Drowning 1317

Diathermy involves the conversion of energy waves into heat. • Niven DJ, Stelfox HT, Laupland KB. Hypothermia in adult ICUs:
Ultrasound or low-frequency microwave radiation can deliver large changing incidence but persistent risk factor for mortality. J Int
amounts of heat to deep tissues. Although animal studies are promising, Care (published online 21 October 2014).
further investigation is needed to determine optimum clinical use. 6,38
■ SUPPORTIVE CARE • Plaisier BR. Thoracic lavage in accidental hypothermia with
cardiac arrest—a report of a case and review of the literature.
Numerous complications are associated with moderate and severe hypo- Resuscitation. 2005;66:99.
thermia and should be anticipated by the clinician. Continuous monitor- • Ruttman E, Weissenbacher A, Ulmer H, et al. Prolonged extra-
ing and frequent reassessment of metabolic and hemodynamic parameters corporeal membrane oxygenation-assisted support provides
are essential to successful outcome. Rhabdomyolysis is frequent and may improved survival in hypothermic patients with cardiocirculatory
result in electrolyte disturbances and renal dysfunction. Compartment arrest. J Thorac Cardiovasc Surg. 2007;134:594.
syndromes may become apparent several days after initial treatment. • Schober A, Sterz F, Handler C, et al. Cardiac arrest due to acciden-
Acute respiratory distress syndrome, acute tubular necrosis, and dissemi- tal hypothermia-A 20 year review of a rare condition in an urban
nated intravascular coagulation may require intensive interventions. area. Resuscitation 2014; Epub ahead PMID 24513157.
• Tsuei BJ, Kearney PA. Hypothermia in the trauma patient. Injury,
PROGNOSIS Int J Care Injured. 2004;35:7.
The prognosis for hypothermia is improved by prompt recognition of • Walpoth BH, Walpoth-Aslan BN, Mattle HP, et al. Outcome of sur-
the clinical presentation and institution of appropriate management vivors of accidental deep hypothermia and circulatory arrest treated
strategies. The risk of death from hypothermia is related to age, pre- with extracorporeal blood rewarming. N Engl J Med. 1997;337:1500.
51
existing illnesses, nutritional status, and alcohol and drug intoxication. • Wang HE, Callaway CE, Peitzman AB, Tisherman SA. Admission
Outcome from severe hypothermia is difficult to predict. Mortality rates hypothermia and outcome after major trauma. Crit Care Med.
vary in several cohorts between 40% and 75%. Clearly, resuscitation 2005;33:1296.
21
will be successful only if cardiac arrest is due to hypothermia and not
a consequence of anoxia or other injuries. Underlying diseases, pre-
cipitating events, and duration and severity of exposure are important
factors to be considered. 59,60 Although the treatment dictum has been REFERENCES
that “no one is dead until warm and dead,” clinical judgment is neces-
sary for determining the most appropriate treatment and termination Complete references available online at www.mhprofessional.com/hall
of efforts. Proposed indicators of prognosis on arrival include severe
21
hyperkalemia (>10 mEq/L), which may indicate death before severe
hypothermia, a venous pH below 6.5, and severe coagulopathy. 36,61 Diving Medicine
CHAPTER
PREVENTION 132 and Drowning

Many episodes of severe hypothermia may be preventable by implement- Claude A. Piantadosi
ing public health strategies that include education programs targeting
high-risk individuals such as the elderly and the homeless. Specific pre-
ventive measures include wearing adequate protective clothing, maintain-
ing fluid and calorie intake, avoiding fatigue, ensuring heated shelter, and KEY POINTS
avoiding excessive alcohol consumption. Emergency departments and • Immersion and diving produce physiologic effects from increased
intensive care units should be prepared to manage victims with hypother- hydrostatic pressure and its effects on the physical behavior of gases.
mia especially in the winter months. Social services should be adequately
staffed to provide counseling and shelter to homeless persons during • Diving with compressed air (or other breathing mixtures) causes the
periods of extreme cold. Family members, home health care workers, and body to take up extra nitrogen or other inert gases in proportion to
social service providers should closely monitor the elderly and patients the pressure change. During ascent, these dissolved gases must leave
with medical conditions that may predispose to hypothermia. gradually through the lungs to avoid decompression sickness (DCS).
• DCS is caused by gases leaving solution and forming bubbles in
body tissues, leading to musculoskeletal pain (bends) or neuro-
KEY REFERENCES logic symptoms due to direct vascular damage, ischemia, edema,
and inflammation.
• Antretter H, Dapunt OE, Bonatti J. Management of profound
hypothermia. Br J Hosp Med. 1995;54:215. • DCS usually manifests within minutes to hours of surfacing and
• Danzl DF, Pozos RS. Accidental hypothermia. N Engl J Med. is emergently treated with high-flow O 2 and the administration
of fluids. Oxygen recompression in a hyperbaric chamber is the
1994;331:1756. definitive treatment for signs and symptoms and for the preven-
• Gentilello LM. Advances in the management of hypothermia. Surg tion of recurrences, even if delayed 1 or 2 days.
Clin North Am. 1995;75:243. • Arterial gas embolism (AGE) is the result of overexpansion of the lungs
• Gregory JS, Bergstein JM, Aprahamian C, et al. Comparison of during ascent from diving with compressed gas. It is usually associated
three methods of rewarming from hypothermia: advantages of with rapid ascent and CNS symptoms and after drowning, is the sec-
extracorporeal blood warming. J Trauma. 1991;31:1247. ond leading cause of fatalities in recreational diving. AGE is a medical
• Koller R, Schnider TW, Neidhart P. Deep accidental hypothermia emergency that also occasionally occurs in the hospital setting.
and cardiac arrest—rewarming with forced air. Acta Anaesthesiol • Drowning is defined by asphyxia in water, and is usually associated
Scand. 1997;41:1359. with aspiration of water. In survivors, the primary injuries are to
• Larach MG. Accidental hypothermia. Lancet. 1995;345:493. the brain, heart, lungs, and kidneys. Drowning is common in chil-
• Lazar HL. The treatment of hypothermia. N Engl J Med. dren, and in young adult males, and is often associated with drug
1997;337:1545. or alcohol ingestion.

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