DO NOT USE FOR CLINICAL PRACTICE
Please use current guidelines available on the UHNM intranet for patient treatment
Please use current guidelines available on the UHNM intranet for patient treatment
RECOGNITION AND ASSESSMENT
- Hypothermia usually occurs with other acute or chronic illness
- occurs at any time of year
- suspect an underlying illness
- older person may be unable to recognise and respond both physiologically and practically to cold
Symptoms and signs
- In mild cases, patient may complain of cold
- this is not reliable
- Symptoms of a precipitating condition
- Shivering may be present in mild cases but is usually absent in severe cases
- Skin (abdomen, inner thigh, axilla) cold, mottled and feels like marble
- Face may appear puffy and myxoedematous
- Muscle rigidity, absent deep reflexes and extensor plantars may be found
- Depressed respiration
- Bradycardia with underlying sinus rhythm or atrial fibrillation
- Hypotension
- Confusional state (delirium)
- Apathy
- Coma when temperature <32°C
Core body temperature
- Measure with tympanic thermometer
Severity
- Mild 35–32°C
- Moderate 31.9–30°C
- Severe <29.9°C
Investigations
Blood
- FBC, U&E, INR, Troponin I
- venous blood pools and may give erroneous results
- Blood glucose
- may be high but falls during rewarming
- Thyroid function tests
- Blood culture. See Collection of blood culture specimens guideline
- Arterial blood gases
- remember to enter core temperature into analyser
Other
- Urinalysis
- ECG
- may show characteristic J wave on the down stroke of the R wave, best seen in leads II and V6, or QTc prolongation
- Chest X-ray
- look for pneumonia, aspiration, pulmonary oedema
Consider associated/causative conditions
- Hypothyroidism
- Hypopituitarism
- Hypoadrenalism
- Stroke
- Epilepsy
- Parkinson's disease
- Fractures
- Drug overdose
- Dementia
- Pneumonia
- Myocardial infarction
- Over-sedation
- Drug-induced
- alcohol, barbiturates, phenothiazines, lithium, tricyclics, opioids
- Heart failure
- Head injury
IMMEDIATE TREATMENT
Supportive treatment
- Special mattress (to prevent pressure sores)
- If hypoxaemic, give controlled oxygen therapy. See Oxygen therapy in acutely hypoxaemic patients guideline
- If pneumonia suspected, see Community-acquired pneumonia guideline
Warming
- Nurse at room temperature of 25–30°C
- Warm with blankets (remember to cover head and neck)
- if available, use Bair Hugger™ (forced air re-warming) blanket
Intensive care unit (ITU)
- Discuss transfer to ITU
- if not responding to re-warming, discuss with ITU consultant on-call as to whether transfer is required
SUBSEQUENT MANAGEMENT
- Most patients will improve spontaneously without further active treatment
- Avoid unnecessary interventions and movement
- these can precipitate cardiac arrhythmia
- Identify and treat other predisposing factors
Patient fails to warm
- Prognosis poor
- If core temperature <30°C, high risk of death
- In moderate-severe hypothermia (<32°C), consultant to consider use of warm IV fluids
- give by IV fluid warmer or a heated infusion pump
- Never warm IV fluids in microwave
- Observe temperature, pulse, BP every 15 min and with continuous cardiac monitoring
- if profound bradycardia persists, contact on-call cardiology SPR to discuss temporary pacing
Cardiac arrest
- Continue cardiac arrest procedures for longer than usual
- hypothermia protects against cerebral hypoxia
Multidisciplinary team assessment
- Once re-warming started in A&E, ensure patient admitted, if aged >65 yr, straight to an elderly care bed
- Assessment by full multidisciplinary team
- If the paramedics have raised a vulnerable adult referral, confirm investigated before discharge
MONITORING TREATMENT
Hourly (if patient requires active re-warming, every 15 min)
- Core temperature with tympanic thermometer
- for mild hypothermia, aim to raise by 0.5–1°C/hr
- for moderate to severe hypothermia, aim to re-warm at 1°C/hr
- if temperature rises by >1°C/hr, cool by removing blankets to maintain peripheral vasoconstriction
- pyrexia after re-warming does not necessarily indicate infection
- Heart rate and rhythm (continuous cardiac monitoring)
- bradycardia and AV block can occur and may require temporary pacing
- ventricular ectopics are suppressed by cold and may appear during warming
- BP
- Respiration
- Glucose
- treat hypoglycaemia with glucose infusion. See Acute hypoglycaemia guideline
- do not treat hyperglycaemia with insulin unless blood glucose persistently >30 mmol/L
- insulin is ineffective in the hypothermic state. Do not use unless re-warming is very slow
2-hrly
- pH (until core temperature >35°C)
- If hypoxaemic or acidotic, PaCO2
COMPLICATIONS
- Paralytic ileus
- Gastric dilatation
- Respiratory failure
- Cardiovascular collapse
- Oliguria
- Gastric ulceration
- Pancreatitis
- Aspiration pneumonia
DISCHARGE AND FOLLOW-UP
- Assess cognitive state immediately before discharge by doing a 6 CIT score
- if cognitive impairment is noted, consider referral to mental health liaison team while patient still in hospital or
- advise GP in the discharge summary to refer to memory clinic
- If the paramedics have raised a vulnerable adult referral, confirm investigated before discharge
- If patient lives alone, ensure they can summon help by telephone or Care Line
- Ensure home is adequately heated
- Ensure patient and family are aware of risks of hypothermia