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Bedside tests for predicting difficult airways : an abridged Cochrane diagnostic test accuracy systematic review

Roth, D.; Pace, N. L.; Lee, A.; Hovhannisyan, K. LU ; Warenits, A. M.; Arrich, J. and Herkner, H. (2019) In Anaesthesia 74(7). p.915-928
Abstract

Although bedside screening tests are routinely used to identify people at high risk of having a difficult airway, their clinical utility is unclear. We estimated the diagnostic accuracy of commonly used bedside examination tests for assessing the airway in adult patients without apparent anatomical abnormalities scheduled to undergo general anaesthesia. We searched for studies that reported our pre-specified bedside index screening tests against a reference standard, published in any language, from date of inception to 16 December 2016, in seven bibliographic databases. We included 133 studies (127 cohort type and 6 case–control) involving 844,206 participants. Overall, their methodological quality (according to QUADAS-2, a standard... (More)

Although bedside screening tests are routinely used to identify people at high risk of having a difficult airway, their clinical utility is unclear. We estimated the diagnostic accuracy of commonly used bedside examination tests for assessing the airway in adult patients without apparent anatomical abnormalities scheduled to undergo general anaesthesia. We searched for studies that reported our pre-specified bedside index screening tests against a reference standard, published in any language, from date of inception to 16 December 2016, in seven bibliographic databases. We included 133 studies (127 cohort type and 6 case–control) involving 844,206 participants. Overall, their methodological quality (according to QUADAS-2, a standard tool for assessing quality of diagnostic accuracy studies) was moderate to high. Our pre-specified tests were: the Mallampati test (6 studies); modified Mallampati test (105 studies); Wilson risk score (6 studies); thyromental distance (52 studies); sternomental distance (18 studies); mouth opening test (34 studies); and the upper lip bite test (30 studies). Difficult facemask ventilation, difficult laryngoscopy, difficult intubation and failed intubation were the reference standards in seven, 92, 50 and two studies, respectively. Across all reference standards, we found all index tests had relatively low sensitivities, with high variability, but specificities were consistently and markedly higher than sensitivities. For difficult laryngoscopy, the sensitivity and specificity (95%CI) of the upper lip bite test were 0.67 (0.45–0.83) and 0.92 (0.86–0.95), respectively; upper lip bite test sensitivity (95%CI) was significantly higher than that for the mouth opening test (0.22, 0.13–0.33; p < 0.001). For difficult tracheal intubation, the modified Mallampati test had a significantly higher sensitivity (95%CI) at 0.51 (0.40–0.61) compared with mouth opening (0.27, 0.16–0.41; p < 0.001) and thyromental distance (0.24, 0.12–0.43; p < 0.001). Although the upper lip bite test showed the most favourable diagnostic test accuracy properties, none of the common bedside screening tests is well suited for detecting unanticipated difficult airways, as many of them are missed.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
airway assessment: co-existing disease, difficult airway, laryngoscopic view: grading, obesity: airway evaluation, sensitivity and specificity
in
Anaesthesia
volume
74
issue
7
pages
915 - 928
publisher
Wiley-Blackwell
external identifiers
  • scopus:85062694916
ISSN
0003-2409
DOI
10.1111/anae.14608
language
English
LU publication?
yes
id
c07d1c56-b141-4635-bc42-202ba5ba535a
date added to LUP
2019-03-19 12:15:04
date last changed
2019-08-14 04:34:01
@article{c07d1c56-b141-4635-bc42-202ba5ba535a,
  abstract     = {<p>Although bedside screening tests are routinely used to identify people at high risk of having a difficult airway, their clinical utility is unclear. We estimated the diagnostic accuracy of commonly used bedside examination tests for assessing the airway in adult patients without apparent anatomical abnormalities scheduled to undergo general anaesthesia. We searched for studies that reported our pre-specified bedside index screening tests against a reference standard, published in any language, from date of inception to 16 December 2016, in seven bibliographic databases. We included 133 studies (127 cohort type and 6 case–control) involving 844,206 participants. Overall, their methodological quality (according to QUADAS-2, a standard tool for assessing quality of diagnostic accuracy studies) was moderate to high. Our pre-specified tests were: the Mallampati test (6 studies); modified Mallampati test (105 studies); Wilson risk score (6 studies); thyromental distance (52 studies); sternomental distance (18 studies); mouth opening test (34 studies); and the upper lip bite test (30 studies). Difficult facemask ventilation, difficult laryngoscopy, difficult intubation and failed intubation were the reference standards in seven, 92, 50 and two studies, respectively. Across all reference standards, we found all index tests had relatively low sensitivities, with high variability, but specificities were consistently and markedly higher than sensitivities. For difficult laryngoscopy, the sensitivity and specificity (95%CI) of the upper lip bite test were 0.67 (0.45–0.83) and 0.92 (0.86–0.95), respectively; upper lip bite test sensitivity (95%CI) was significantly higher than that for the mouth opening test (0.22, 0.13–0.33; p &lt; 0.001). For difficult tracheal intubation, the modified Mallampati test had a significantly higher sensitivity (95%CI) at 0.51 (0.40–0.61) compared with mouth opening (0.27, 0.16–0.41; p &lt; 0.001) and thyromental distance (0.24, 0.12–0.43; p &lt; 0.001). Although the upper lip bite test showed the most favourable diagnostic test accuracy properties, none of the common bedside screening tests is well suited for detecting unanticipated difficult airways, as many of them are missed.</p>},
  author       = {Roth, D. and Pace, N. L. and Lee, A. and Hovhannisyan, K. and Warenits, A. M. and Arrich, J. and Herkner, H.},
  issn         = {0003-2409},
  keyword      = {airway assessment: co-existing disease,difficult airway,laryngoscopic view: grading,obesity: airway evaluation,sensitivity and specificity},
  language     = {eng},
  number       = {7},
  pages        = {915--928},
  publisher    = {Wiley-Blackwell},
  series       = {Anaesthesia},
  title        = {Bedside tests for predicting difficult airways : an abridged Cochrane diagnostic test accuracy systematic review},
  url          = {http://dx.doi.org/10.1111/anae.14608},
  volume       = {74},
  year         = {2019},
}