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Three Part Question

In [patients with presumed GHB intoxication and respiratory depression] is [endotracheal intubation more effective than non-invasive airway management] at [reducing the complications of an unprotected airway]?

Clinical Scenario

A comatose 20 year old male is brought to casualty with a GCS of 3/15 and in respiratory arrest. Acute overdose with gamma-hyroxybutyric acid is suspected. Ventilation is initially assisted with a bag and mask. Your anaesthetic colleagues are very reluctant to intubate the patient as they state that the patient will wake up soon and there are no beds on ITU.

Search Strategy

Medline 1966-09/2004 using the OVID interface.
Medline 1966-09/04 using the OVID interface.
[exp Hydroxybutyrates OR gamma hydroxybutyric acid.mp. OR GHB.mp] AND [exp Poisoning OR intoxication.mp OR exp Overdose OR overdose.mp] LIMIT to English language

Search Outcome

Altogether 95 papers were found. Two papers were relevant to the three part question.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Chin RL et al, 1998, USA	88 patients with GHB ingestion. 1993-1996. Single ED in San Francisco. 11/88 patients were intubated	Retrospective note review over a 3 year period	Intubation	13% (11) intubated. 73% (8) of those intubated had GCS 3, 27% (3) had GCS 4-7. 73% also had bradycardia. Mean duration of intubation = 179 mins. 9 of these were admitted for 24 hrs. 2 were discharged directly	Retrospective analysis. GHB ingestion confirmed from case notes, not toxicological testing Clinical picture of GHB toxication often complicated by other substances Differences in recovery time may reflect use of sedative agents during intubation, or the initial severity of presentation among intubated group
			Co-ingestion of other drugs	Co-ingestion: 39% (34) alcohol, 28% (25) other drugs
			Time to regaining conciousness	Intubation related to recovery time: mean time to recovery among non-intubated = 146 mins (16-389). Mean time to recovery among intubated = 274 mins (161-439)
			Aspiration	No record of aspiration in any patient
			GCS	28% (25) GCS=3, 32% (28) GCS=4-8, 40% (35) GCS=9-15
Li J et al, 1998, USA	7 patients with GHB ingestion, identified by urine spectrometry	Case Report	Aspiration	No record of aspiration	Case report Small number of patients No record of any adverse events
			No intubation	1 patient not intubated
			Time to extubation	Time to extubation 6, 4, 2 and 2 hrs. 1 patient required sedation
			Intubation	4 intubated
			Atempted intubation	2 failed intubations, patients observed thereafter
			Pre-hospital GCS	6 had GCS <9, 1 had GCS >9

Comment(s)

The evidence for and against endotracheal intubation is scanty. These reports suggest show no evidence for aspiration but the numbers involved (of non-intubated patients) are small. There is insufficient evidence here to change the standard approach to airway management in the unconcious patient. The reduced GCS is an indication for airway protection that would normally be achieved using a rapid sequence induction of anaesthesia.

Editor Comment

Updated May 2004 - no new papers Comments and bottom line amended by SDC September 2004

Clinical Bottom Line

In patients with suspected GHB toxicity, reduced GCS and a threatened airway, rapid sequence induction and intubation should be performed.

Level of Evidence

Level 3 - Small numbers of small studies or great heterogeneity or very different population.

References

1. Chin RL, Sporer KA, Cullison B et al. Clinical course of gamma-hydroxybutyrate overdose. Ann Emerg Med 1998;31(6):716-22.
2. Li J, Stokes SA, Woeckener A. A Tale of Novel Intoxication: Seven cases of gamma-hydroxybutyric acid overdose. Ann Emerg Med 1998;31(6):723-28.