Medical Emergencies in Dental Practice
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Direct answer
Be ready for syncope before anything else: vasovagal syncope is the commonest medical emergency in dental practice, and the response — stop the procedure, supine with legs raised, oxygen, reassurance — resolves most episodes within minutes. The emergencies that kill are anaphylaxis (intramuscular adrenaline 1:1000, 0.5 mg into the anterolateral thigh, repeated every five minutes), hypoglycaemia in the insulin-dependent diabetic, acute severe asthma, seizures, and cardiac arrest, for which current basic life support is 30 compressions to 2 ventilations at 100-120 per minute with early defibrillation.
What you must remember
- Vasovagal syncope: pallor, sweating, nausea, visual dimming, brief loss of consciousness; supine with legs elevated reverses it; the classical error is sitting the patient upright.
- Anaphylaxis: urticaria, angio-oedema, wheeze, stridor, hypotension within minutes; adrenaline 0.5 mg intramuscularly (0.5 mL of 1:1000) in adults — children 0.01 mg/kg to a 0.5 mg maximum — anterolateral thigh, repeated every five minutes; oxygen, supine legs raised, fluids, hospital transfer; steroids and antihistamines are second-line.
- Hypoglycaemia: conscious — oral glucose by the rule of 15 (15 g, recheck at 15 minutes); unconscious — glucagon 1 mg intramuscularly or intravenous dextrose, nothing by mouth.
- Angina and infarction: rest and sublingual glyceryl trinitrate repeated at five-minute intervals to three doses; unrelieved pain beyond 15-20 minutes is infarction — chew aspirin 300 mg, oxygen if hypoxic, ambulance; avoid GTN with recent phosphodiesterase-5 inhibitor use.
- Acute severe asthma: salbutamol by spacer, oxygen, sitting up; silent chest, exhaustion or cyanosis means ambulance now.
- Seizures: protect, time the fit, recovery position after; beyond five minutes (status) needs an ambulance and benzodiazepines — buccal or intranasal midazolam has replaced rectal diazepam.
- Cardiac arrest: unresponsive and not breathing normally — call for help and an AED, compressions 5-6 cm deep at 100-120 per minute, 30:2.
- The clinic kit: adrenaline 1:1000, oxygen, glucose gel, glucagon, GTN spray, aspirin 300 mg, salbutamol inhaler with spacer, midazolam, bag-valve-mask, airways, pulse oximeter — expiry-checked monthly.
- Prevention beats response: morning appointments for insulin-dependent diabetics, aspiration before injection, steroid supplementation before major surgery.
A worked emergency drill
Run the drill your examiners want narrated. A patient becomes pale and sweaty two minutes after a local anaesthetic injection, complaining of nausea and faintness. First action: lay the chair fully supine with legs raised — if this is syncope, colour and consciousness return within a minute or two; the pulse is weak and slow, and oxygen completes the response. If instead the patient develops widespread urticaria, lip swelling, a tight wheeze and a thready rapid pulse, the diagnosis pivots to anaphylaxis: call for help and an ambulance, give adrenaline 0.5 mg intramuscularly into the thigh without delay, high-flow oxygen, supine with legs raised, and repeat the adrenaline at five-minute intervals if shock persists; only then add antihistamine and hydrocortisone, and admit for observation because of biphasic reactions. The pitfall the drill exposes: waiting for "full-blown" anaphylaxis, or reaching first for hydrocortisone — a drug that acts in hours — while the patient needs adrenaline in minutes. Adrenaline within the first five minutes is the single intervention that changes outcome, exactly as defibrillation is in arrest.
Where students slip
Dose confusion is the commonest failure: adrenaline 1:1000 intramuscularly (0.5 mg) for anaphylaxis is written wrongly as the 1:10,000 intravenous preparation, or diluted into a nebule; the exam expects 1:1000, half a milligram, anterolateral thigh. The second slip is the syncope reflex: propping the fainting patient more upright, or abandoning the supine position the moment they rouse. The third is sequencing the arrested patient: checking the pulse longer than ten seconds or delaying compressions — current BLS starts compressions on an unresponsive non-breathing patient, with the AED applied the moment it arrives.
Frequently asked questions
What is the commonest medical emergency in the dental chair?
Vasovagal syncope — managed by stopping the procedure, supine positioning with elevated legs, oxygen and reassurance; it resolves rapidly.
What is the adult dose of adrenaline in anaphylaxis?
0.5 mg intramuscularly — 0.5 mL of 1:1000 — anterolateral thigh, repeated every five minutes; children 0.01 mg/kg up to 0.5 mg.
How is conscious hypoglycaemia managed in the clinic?
Oral glucose by the rule of 15 — about 15 g of glucose gel or sugar, repeating in 15 minutes if the patient remains symptomatic, then a complex snack.
When is chest pain treated as a myocardial infarction?
When it fails to respond to GTN or persists beyond about 15 minutes, especially with sweating, nausea and breathlessness — then aspirin 300 mg chewed, oxygen if hypoxic, ambulance.
What is the current compression standard in adult basic life support?
Compressions 5-6 cm deep at a rate of 100-120 per minute in a 30:2 ratio with ventilations, with minimal interruption and early AED use.
Why is buccal midazolam preferred for prolonged seizures?
It terminates seizures through buccal absorption without intravenous access, has largely replaced rectal diazepam, and can be given safely by trained dental staff while awaiting the ambulance.