ICU 360

Staging and rewarming accidental hypothermia, hypothermic cardiac arrest, and ICU care after electrical and lightning injuries.

Definition

Accidental hypothermia = core temperature < 35 °C. Electrical injury: low voltage (< 1000 V, domestic 230 V in India) or high voltage (≥ 1000 V, overhead lines); lightning is a separate pattern.

At the bedside

Timed steps

1
Measure core temperature and stage
0 min
Low-reading thermometer, oesophageal probe if intubated. Stage by consciousness and temperature: mild 32-35 °C (shivering, conscious), moderate 28-32 °C (drowsy, shivering stops), severe < 28 °C (unconscious), and risk of arrest highest < 28 °C (VF/asystole).
2
Handle gently and rewarm
Horizontal position, gentle handling (VF risk). Mild: passive (dry, blankets, warm room) plus active external (forced-air warming). Moderate-severe: active external + warmed IV fluids (38-42 °C) and warm humidified gases; consider active internal methods.
3
Unstable or arrested: ECLS centre
Cardiac arrest or instability (SBP < 90, ventricular arrhythmia, core < 30 °C with instability): refer for ECLS/ECMO rewarming if available; continue CPR during transfer (mechanical CPR helps).
4
Hypothermic cardiac arrest modifications
Check pulse for up to 1 min. If VF and < 30 °C: up to 3 shocks; withhold further shocks and adrenaline until > 30 °C. 30-35 °C: double drug intervals. Prolonged CPR is justified ('not dead until warm and dead'). Serum K > 12 mmol/L suggests futility (HOPE score helps decide ECLS).
5
Electrical injury: assess and monitor
Low-voltage, asymptomatic, normal ECG, no loss of consciousness: discharge. Otherwise (high voltage, LOC, abnormal ECG, chest pain, pregnancy): ECG monitoring 24 h, troponin, CK, urine myoglobin.
6
Electrical injury: hidden damage
Small skin wounds hide deep muscle necrosis. Fluids to urine output 1-1.5 mL/kg/h if myoglobinuria; watch for compartment syndrome (fasciotomy); look for falls/trauma, spinal injury, cataracts later.
7
Lightning
Cardiac arrest is usually asystole with prolonged apnoea: in mass casualties resuscitate the apparently dead first (reverse triage). Keraunoparalysis (transient limb paralysis) and ruptured tympanic membranes are common.

Volume during rewarming

Warmed IV fluids (0.9% saline or RL at 38-42 °C)

IV (warmed 38-42 °C)

Dose: 250-500 mL boluses as needed

Hypothermia staging and rewarming

Stage	Core temp	Clinical	Rewarming
Mild	32-35 °C	Conscious, shivering	Passive + active external, warm drinks
Moderate	28-32 °C	Drowsy, shivering stops, bradycardia, J (Osborn) waves	Active external + warm IV fluids, gentle handling
Severe	< 28 °C	Unconscious, high VF risk	Active internal; ECLS if unstable
Arrest	Usually < 28 °C	No signs of life	CPR + ECLS rewarming

Red flag · call your senior now

Rough handling or moving a severely hypothermic patient upright can precipitate VF ('rescue collapse').

Red flag

High-voltage electrical injury with dark urine: massive rhabdomyolysis and compartment syndrome risk.

Pitfall

Declaring death in a cold patient before rewarming to > 32 °C (unless lethal injuries, frozen chest or K > 12 mmol/L).

Pitfall

Judging electrical injury severity by skin burn size.

Pearl

Osborn (J) waves on ECG are characteristic of hypothermia and resolve with rewarming.

Pearl

In India hypothermia occurs in the elderly and homeless in north Indian winters, in Himalayan regions, and after cold-water drowning; consider sepsis and hypothyroidism.

References

Test yourself

Module quiz · score 70% to complete the module

Drowning

Educational reference for trained clinicians. Check doses against your hospital protocol and the patient in front of you.

Hypothermia and electrical injury

At the bedside

Warmed IV fluids (0.9% saline or RL at 38-42 °C)

Hypothermia staging and rewarming

References

Accidental hypothermia

Pathophysiology

Evidence

Controversies

🇮🇳 India notes

References