Critical Care Emergencies 33SEVERE HEAD INJURY(ii) Hypoxia
(a) PaO 2 <70 mmHg (9 kPa) breathing air or 100 mmHg
(13 kPa) on supplemental oxygen and hypercarbia with
PaCO 2 over 45 mmHg (6 kPa) in the spontaneously breathing
patient requires active intervention
(b) call for urgent senior ED doctor help and prepare for
endotracheal intubation using an RSI technique (see p. 467)
to protect the airway, if not already performed.
(iii) Seizures
(a) give midazolam 0.05–0.1 mg/kg up to 10 mg i.v., diazepam
0.1–0.2 mg/kg up to 20 mg i.v. or lorazepam 0.07 mg/kg up to
4 mg i.v.
(b) follow with phenytoin 15–18 mg/kg i.v. (see p. 92).
(iv) Pinpoint pupils
(a) give naloxone 0.8–2 mg i.v.
(b) no response may indicate pontine or cerebellar damage.
(v) Restless or aggressive behaviour
Check if any of the following are present:
(a) hypoxia: make sure the airway is still patent and high-flow
oxygen is being delivered
(b) hypotension: repeat the blood pressure
(c) pain: catheterize the bladder, splint fractures and exclude a
constricting bandage or tight cast.
(vi) Gastric distension
(a) pass a large-bore nasogastric tube
(b) use an orogastric tube if a basal skull or mid-face fracture is
present.9 Look out for signs of increasing intracranial pressure and uncal trans-
tentorial herniation (‘coning’), e.g. a deteriorating level of consciousness,
bradycardia, hypertension and focal neurological signs, e.g. a dilated pupil:
(i) Call for a skilled doctor to perform an RSI intubation, if an
endotracheal tube is not already positioned.
(ii) Mildly hyperventilate the patient to maintain PaCO 2 at 30–35
mmHg (4.0–4.7 kPa).
(iii) Give 20% mannitol 0.5–1 g/kg (2.5–5 mL/kg) as an osmotic
diuretic, provided adequate circulatory volume resuscitation has
occurred.
(iv) Arrange immediate neurosurgical intervention.
10 Give f lucloxacillin 1 g i.v. or cefuroxime 1.5 g i.v. if a penetrating or
compound skull fracture or intracranial air is found, and tetanus
prophylaxis.