Tox i c o l o g y 16 7ACUTE POISONING: GENERAL PRINCIPLES(iv) Look for clues to the substance taken (‘toxidrome’):
(a) dilated pupils: tricyclics, amphetamine, antihistamines,
anticholinergic agents
(b) pinpoint pupils: opiates, organophosphates
(c) nystagmus: alcohol, benzodiazepines, phenytoin
(d) hyperventilation: salicylates
(e) nasal bleeding or perioral sores: solvent abuse.5 Gain i.v. access and send blood for FBC, U&Es, LFTs, a paracetamol level in
all poisonings, and a salicylate level only if symptomatic of salicylism or
when comatose (see p. 172).
6 Perform an arterial blood gas to rapidly determine metabolic acidosis, respira-
tory function and electrolyte imbalance, if the patient is significantly unwell.
(i) Metabolic acidosis is associated with many poisonings including
salicylates, methanol, iron and ethylene glycol.
7 Request other specific measurable serum drug levels in ingestion of pheny-
toin, sodium valproate, digoxin, carbamazepine, iron, methotrexate and
theophylline.
8 Perform an electrocardiogram (ECG) to look for tachycardia, bradycardia
and potential cardiac conduction abnormalities such as QT prolongation
and widening of the QRS complex.
9 Request a chest X-ray (CXR) if clinical signs of aspiration are present.
10 Request an abdominal X-ray (AXR) when potentially radiopaque tablets
such as iron or potassium have been ingested.
MANAGEMENT1 Start immediate resuscitation if risk assessment indicates ingestion of a
potentially lethal drug, or if the patient is obtunded with signs of cardio-
respiratory distress.
2 Unconscious or collapsed patient
(i) Clear the airway by extending the head, remove dentures, vomit
or blood by a quick sweep round the mouth with a Yankauer
suction catheter, and give oxygen via a face mask.
(ii) Insert an oropharyngeal Guedel airway if the patient is not
breathing or the gag reflex is reduced, and use a bag–valve mask
system to ventilate the patient, aiming for an oxygen saturation
above 94%.
(iii) Call an airway-skilled doctor urgently to pass a cuffed
endotracheal tube to protect and maintain the airway and to
optimize ventilation.
3 Administer the following without delay:
(i) 50% dextrose 50 mL i.v. if the blood sugar level is low.
(ii) Naloxone 0.1–0.4 mg i.v. slowly if the pupils are pinpoint, the