[Rewarming from moderate to deep hypothermia: plasma catecholamine content, metabolism and circulatory function. 2...

Area of Science:

• Cardiology
• Physiology
• Toxicology

Background:

• Hypothermia presents significant physiological challenges, particularly during rewarming.
• Cardiac complications are a concern during the rewarming of hypothermic patients.
• Understanding the role of thermoregulation and catecholamines is crucial for managing hypothermia.

Observation:

• Two patients with severe hypothermia (esophageal temperatures 27.2°C and 27.5°C) were rewarmed.
• Patient 1, with head injury and alcohol intoxication, showed no metabolic or cardiovascular response to cold, with elevated epinephrine and moderate norepinephrine.
• Patient 2, an elderly man, exhibited shivering, indicating persistent thermoregulation, with higher norepinephrine than epinephrine levels.

Findings:

• Rewarming revealed a Q10 of 2.75 for whole-body oxygen consumption in Patient 1.
• Patient 2 developed premature ventricular contractions (PVCs) during rewarming, coinciding with increased norepinephrine levels.
• Cardiac complications during rewarming may be linked to thermoregulation and catecholamine release.

Implications:

• Thermoregulation and subsequent catecholamine surges during rewarming can precipitate cardiac arrhythmias.
• These findings suggest a mechanism for cardiac complications in deep hypothermia patients.
• Further research into managing catecholamine levels during rewarming may improve patient outcomes.