Clinical features

ask about ^b

• drug paraphernalia where the patient was found
• needle track marks on skin
• history of iv drug use by bystanders

• a reduced respiratory rate
• pinpoint pupils 

Why?

A reduced respiratory rate, pinpoint pupils and evidence of drug misuse make opiate overdose more likely

Patient	Target Disorder and Reference Standard	Diagnostic Test	LR+ (95% CI)	Post-test Probability	LR- (95% CI)	Post-test Probability
altered mental state b (pre-test probability: 10%)	opiate overdose (physician review of hospital chart)	respiration < 13 breaths/minute	14 (7.8 to 24)	61%	0.21 (0.097 to 0.47)	2.3%
		pinpoint pupils	5.1	37%	0.28 (0.14 to 0.57)	3.1%
		circumstantial evidence: drug paraphernalia where found; needle track marks on skin; history of iv drug use by bystanders	14 (7.2 to 26)	61%	0.34 (0.19 to 0.60)	3.7%
		any of the above	3.8 (3.0 to 5.0)	30%	0.11 (0.028 to 0.40)	1.2%