INTER-OBSERVER REPRODUCIBILITY OF 15 TESTS USED FOR PREDICTING DIFFICULT INTUBATION

Milan Adamus,Ondrej Jor,Jana Zapletalova,Tereza Vavreckova,Vladimir Janout,Tomas Gabrhelik,Lumir Hrabalek,Hana Tomaskova

doi:10.5507/bp.2011.041

Milan Adamus, Ondrej Jor + Show 6 more

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https://doi.org/10.5507/bp.2011.041

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Abstract

To determine the inter-observer reproducibility of 15 tests used for predicting difficult tracheal intubation (DI). Following local ethics committee approval and informed consent, 101 volunteers were examined by two assessors using 15 tests for predicting DI. The two assessors who were blinded to the results of the other, examined each volunteer independently. Cohen's kappa (κ) or first-order agreement coefficient (AC1) were used to measure agreement between assessor ratings on a qualitative scale. Agreement between two quantitative outcomes was described using the intraclass correlation coefficient (ICC) and Pearson's (PCC) or Spearman's (SCC) correlation coefficients. The following interpretation of the coefficients was used: poor (< 0.20), fair (0.21-0.40), satisfactory (0.41-0.60), good (0.61-0.80), and excellent (0.81-1.00). Respective coefficients of inter-rater agreement and correlation coefficients were determined for the following parameters: pathologies associated with DI (κ=0.662, AC1=0.990), clinical impression (κ=-0.013, AC1=0.969), modified Mallampati test (κ=0.503, AC1=0.861), upper lip bite test (κ=0.370, AC1=0.897), temporo-mandibular joint movement (κ=0.088, AC1=0.797), max. anteroflexion of C-spine (ICC=0.136, SCC=0.391), max. retroflexion of C-spine (ICC=0.020, SCC=0.284), mandibular length (ICC=0.301, SCC=0.553), neck circumference (ICC=0.832, SCC=0.928), hyo-mental distance (ICC=0.378, SCC=0.472), thyro-mental distance (ICC=-0.002, PCC=0.265), sternomental distance (ICC=0.674, PCC=0.815), and finally, inter-incisor gap (ICC=0.695, PCC=0.785). Two tests (positive history of DI and retrogenia), were excluded from calculation because no positive cases were found. Best inter-rater agreement was found for the assessment of neck circumference while the highest discrepancies between raters were in goniometrically-measured mobility of the C-spine. Many of the pre-operative airway tests had only fair inter-observer reproducibility. This may be one reason why models for predicting difficult intubation are not universally reliable.

Highlights

Tracheal intubation is a mainstay of airway management during general anesthesia and usually performed uneventfully
Best inter-rater agreement was found for the assessment of neck circumference while the highest discrepancies between raters were in goniometrically-measured mobility of the C-spine
Does the patient have a history of difficult intubation? Does the patient have a condition commonly associated with difficult intubation? Hard to define – a feeling of a potential airways problem

Summary

Introduction

Tracheal intubation is a mainstay of airway management during general anesthesia and usually performed uneventfully. Unanticipated difficult intubation can be more dangerous than a predicted one when a potential airway problem is detected before anesthesia. There are many clinical tests for predicting difficult intubation (DI). Single tests, such as Mallampati classification, are not reliable enough to prospectively detect all cases of DI (ref.[1,2,3,4]). Studies have demonstrated conflicting results in the predictive value of models consisting of different test combinations[5,6,7]. A correct model must be both reliable in classifying patients’ airway and give the same results when performed by different assessors (reproducibility)

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