The gag reflex is a poor discriminator for the need for intubation
Date First Published:
March 1, 2000
Last Updated:
November 8, 2003
Report by:
Kevin Mackway-Jones, Consultant (Manchester Royal Infirmary)
Search checked by:
Chris Moulton, Manchester Royal Infirmary
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)
Search Details:
[gag reflex.mp]
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):
| Study Title | Patient Group | Study type (level of evidence) | Outcomes | Key results | Study Weaknesses |
|---|---|---|---|---|---|
| Gag reflex in assessing level of consciousness. Kulig K, Rumack BH, Rosen P. 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<br><br>1 patient without a gag reflex was fully awake | |
| Relation between Glasgow coma scale and the gag reflex. Moulton C, Pennycook A, Makower R. 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.<br><br>In more conscious patients (GCS > 8) 64% of those exposed to drugs had depressed gag compared with 8% of those with head injury. | |
| The use of the Glasgow Coma Scale in poisoning. Chan B, Gaudry P, Grattan-Smith TM. 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% | ||||
| Pharyngeal sensation and gag reflex in healthy subjects. Davies AE, Kidd D, Stone SP et al. 1995 UK | 140 healthy volunteers Gag reflex assessed |
Observational | Presence of gag reflex | Gag reflex was absent in 37% of subjects | |
| Gag reflex and dysphagia. Leder SB. 1996 USA | 63 healthy volunteers Gag reflex assessed |
Observational | Presence of gag reflex | Gag reflex was absent in 13% of subjects |
Author Commentary:
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.
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:
- Kulig K, Rumack BH, Rosen P.. Gag reflex in assessing level of consciousness.
- Moulton C, Pennycook A, Makower R.. Relation between Glasgow coma scale and the gag reflex.
- Chan B, Gaudry P, Grattan-Smith TM.. The use of the Glasgow Coma Scale in poisoning.
- Davies AE, Kidd D, Stone SP et al.. Pharyngeal sensation and gag reflex in healthy subjects.
- Leder SB.. Gag reflex and dysphagia.