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Three Part Question

In [an adult with decreased conscious level] is [the gag reflex] a [good predictor of the need for intubation]?

Clinical Scenario

A 25 year old woman is brought to the emergency department having taken an overdose of drugs. She will require gastric lavage but you consider that her airway is at risk. You call the duty anaesthetist who examines her and states that she does not need intubation as her gag reflex is present. You wonder whether gag reflex is a good test to predict the need for intubation.

Search Strategy

Medline 1966-10/03 using the OVID interface on ATHENS (including Medline in progress and other non-indexed citations)
[gag reflex.mp]

Search Outcome

170 papers found of which 165 were irrelevant to the study question or of insufficient quality for inclusion. The remaining 5 papers are shown in the table.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Kulig K et al 1982 USA	38 emergency room patients Gag reflex assessed	Observational	Presence of gag reflex matched to conscious level	12 patients with a gag reflex were significantly obtunded 1 patient without a gag reflex was fully awake
Moulton C et al 1991 UK	111 emergency department patients requiring neurological observation Gag reflex and GCS assessed	Observational	Presence of gag reflex matched to conscious level	Gag reflex may be significantly attenuated or absent at all levels of GCS. In more conscious patients (GCS > 8) 64% of those exposed to drugs had depressed gag compared with 8% of those with head injury.
Chan B et al 1993 Australia	414 patients with poisoning attending an emergency department Prediction of need for intubation	Diagnostic	GCS < 8	sensitivity 90%, specificity 95%	Gold standard is clinical judgement
			Absence of gag on admission	sensitivity 70%, specificity 100%
Davies E et al 1995 UK	140 healthy volunteers Gag reflex assessed	Observational	Presence of gag reflex	Gag reflex was absent in 37% of subjects
Leder SB 1996 USA	63 healthy volunteers Gag reflex assessed	Observational	Presence of gag reflex	Gag reflex was absent in 13% of subjects

Comment(s)

The high incidence of absence of the gag reflex in normal volunteers argues against its usefulness as a specific predictor of need for intubation. It is suprising, therefore, that there appears to be low sensitivity and high specificity in the clinical study of poisoned patients. In this study the sensitivity is too low to allow presence of gag to rule-out (SnOut) the need for intubation. Other reflexes may be more predictive.

Editor Comment

Search redone on 10/03. No new papers found.

Clinical Bottom Line

The presence or absence of a gag reflex does not accurately predict the need for intubation.

Level of Evidence

Level 2 - Studies considered were neither 1 or 3.

References

1. Kulig K, Rumack BH, Rosen P. Gag reflex in assessing level of consciousness. Lancet 1982; 1(8271):565.
2. Moulton C, Pennycook A, Makower R. Relation between Glasgow coma scale and the gag reflex. BMJ 1991; 303(6812):1240-1241.
3. Chan B, Gaudry P, Grattan-Smith TM. The use of the Glasgow Coma Scale in poisoning. J Emerg Med 1993; 11(5):579-582.
4. Davies AE, Kidd D, Stone SP et al. Pharyngeal sensation and gag reflex in healthy subjects. Lancet 1995; 345(8948):487-488.
5. Leder SB. Gag reflex and dysphagia. Head & Neck 1996;18(2):138-41.