The onset and severity of acute opioid toxicity in heroin overdose cases: a retrospective cohort study at a supervised injecting facility in Melbourne, Australia

Figures & data

Figure 1. The severity of acute opioid toxicity for heroin overdose cases.

Table 1. Typical physiological findings associated with the different severity categories of acute opioid toxicity.

Severity of acute opioid toxicity	Grade 1	Grade 2	Grade 3
			3a. Acute respiratory depression	3b. Persistent altered consciousness
Level of consciousness using AVPU^a scale	A 17% (n = 165)	A 2% (n = 2)	A 2% (n = 2)	A 6% (n = 4)
	V 58% (n = 555)	V 17% (n = 14)	V 2% (n = 2)	V 25% (n = 18)
	P 17% (n = 163)	P 14% (n = 12)	P 2% (n = 2)	P 35% (n = 25)
	U 8% (n = 72)	U 66% (n = 55)	U 93% (n = 83)	U 35% (n = 25)
Median respiratory rate	4/min	1/min	0/min	4/min
	(IQR 4–6 breaths)	(IQR 0–4 breaths)	(IQR 0–2 breaths)	(IQR 2–6 breaths)
Median SpO2 (%)	78%	62%	53%	78%
	(IQR 69–85%)	(IQR 47–78%)	(IQR 40–72%)	(IQR 70–87%)
Number of cases in each category% (n)	78% (n = 955)	7% (n = 83)	7% (n = 89)	6% (n = 72)

^aAVPU: alert; responds to voice; responds to pain; unresponsive.

Figure 2. The onset time of heroin overdose events.