Diagnostic accuracy of radiology (CT, X-ray, US) for predicting difficult intubation in adults: A meta-analysis

doi:10.1016/j.jclinane.2017.12.023

Journal of Clinical Anesthesia

Volume 45, March 2018, Pages 79-87

https://doi.org/10.1016/j.jclinane.2017.12.023 Get rights and content

Highlights

•
Difficult airway management still occurs and it prompts increased risk of morbidity especially when not anticipated.
•
Radiology is a newly developed method that is capable of predicting difficult intubation.
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The diagnostic value of US is similar to that of CT and X-ray but much better than that of the modified Mallampati score.
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Studies on comparisons between radiology and clinical method will be required before recommending its routine clinical use.
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US is superior to CT or X-ray due to the real-time observation of upper airway, low cost and no requirement for radiation.

Abstract

Objective

The aim of this study was to evaluate the overall accuracy of radiological measurements in prediction of difficult airway and compare the diagnostic value between the radiological measurements and the modified Mallampati score through a meta-analysis of published studies.

Methods

A comprehensive electronic search of related literature was performed in PubMed, Embase, Cochrane Library and China National Knowledge Infrastructure. Meta-DiSc 1.4 and STATA 12.0 were selected for data analysis, and QUADAS-2 tool was used to assess the quality of included studies. Difficult airway was defined as Cormack-Lehane III-IV. Data from selected studies were pooled to yield summary sensitivity, specificity, positive and negative likelihood ratios, diagnostic odds ratio, as well as summary receiver operating characteristic curve.

Results

A total of 17 studies dating up to November 2017 with 8779 individuals were enrolled in the present study. Heterogeneity existed in the non-threshold effect, but not in the threshold effect. Subgroup analyses based on radiological methods were conducted. The pooled diagnostic characteristics in the computed tomography subgroup were as follows: sensitivity 0.75 (95%CI, 0.64–0.84), specificity 0.75 (95%CI 0.68–0.81), PLR 3.19 (95%CI 1.91–5.32), NLR 0.38 (95%CI 0.23–0.64), DOR 11.74 (95% CI, 4.19–32.86) and AUC 0.8424 with Q* index 0.7741. In the X-ray subgroup, the sensitivity was 0.78 (95%CI, 0.73–0.82), the specificity was 0.88 (95%CI, 0.87–0.89), PLR was 5.03 (95%CI, 2.44–10.37), NLR was 0.27 (95%CI, 0.22–0.33), DOR was 23.18 (95%CI, 8.81–60.95) and AUC was 0.8970 with Q* index 0.8280. The corresponding values for the ultrasound subgroup were 0.69 (95%CI, 0.63–0.74) for sensitivity, 0.84 (95%CI, 0.82–0.85) for specificity, 6.25 (95%CI, 3.81–10.27) for PLR, 0.36 (95%CI, 0.27–0.47) for NLR, 22.26 (95%CI, 10.45–47.41) for DOR, 0.8942 for AUC with Q* index 0.8251. The pooled sensitivity, specificity and PLR of the modified Mallampati score were 0.61 (95%CI 0.56–0.66), 0.63 (95%CI 0.61–0.64) and 2.11 (95%CI 1.71–2.61) which were significantly lower than that of radiographic methods.

Conclusions

The results indicated that the diagnostic value of CT, X-ray and US was much better than that of modified Mallampati score. Ultrasound had diagnostic indices and the area under curve similar to those of CT and X-ray in predicting difficult airway. Considering being easy, readily availability, low cost, and free from radiological hazards, it can be considered as prior diagnostic strategy in this condition.

Introduction

Difficulties with airway management in relation to general anaesthesia have been a challenge for the anesthesiologist since the birth of anaesthesia. Difficult airways can cause ventilation failure, oxygen desaturation, arrhythmia, bronchoconstriction, airway injury, cardiac arrest, brain damage, or even death in anesthetic practice [1]. Thus looking for a reliable tool for precise diagnosis and prediction of difficult airway is of utmost importance, but the fact that which of these anatomical land marks and clinical factors are the best is still uncertain or is controversial [2], [3].

Current bedside tests have limited and inconsistent capacity to discriminate between patients with difficult and easy intubation [4]. A standard method for evaluation of difficult laryngoscopy is using modified Mallampati score (MMS) [5], [6]. However, MMS has been reported to be a good predictor by many, but was found to be of limited value by others [7]. Moreover, there is no bedside screening test has a high performance even when tests are combined [8]. It is well known that failure to estimate difficult airway in relation to anaesthesia cause severe morbidity and mortality. Unanticipated difficult intubation has been associated with unwanted patient outcomes in the operating room [1], [9]. Prediction of difficult airway continue to represent a patient safety concern.

Adequate preoperative airway planning, including specific techniques and equipment tailored to each specific patient, can play an important role in decreasing the risks associated with difficult airway management. Imaging techniques, such as computed tomography (CT), magnetic resonance imaging (MRI), X-ray and ultrasound (US), display the anatomical features of the upper airways well and have been recommended for evaluation of difficult airway [10], [11], [12], [13]. However, there was a large variability regarding the results and sample sizes of these studies. For instance, the specificity in the report of Di et al. [14] was only 0.5, whereas specificity was 0.97 in the study of Naguib et al. [10]. Thus, the real value of radiology in diagnosing difficult airway is uncertain. Moreover, the findings of present reports were based on the results of individual clinical trials, and the literature lacks a pooled and robust appraisal of all the evidence for the diagnostic accuracy of radiological measurements. Meta-analysis of the diagnostic efficiency are rigorous approaches for examining and synthesizing the evidence in the evaluation of the diagnostic and screening test [15]. Therefore, we conduct this meta-analysis to determine the relationship between radiology and difficult airway to precisely estimate the diagnostic accuracy of the radiological methods.

Section snippets

Search strategy

This meta-analysis was conducted according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) statement and methods [16]. A comprehensive retrieval in PubMed, Embase, Cochrane Library, and China National Knowledge Infrastructure (CNKI) was carried out to search relevant articles that evaluate the diagnostic value of radiology (CT, MRI, X-ray, US) for predicting difficult airway dating from 1991 up to November 2017. We used the terms “difficult airway” OR “difficult

Literature search and characteristics of included studies

A total of 780 potentially eligible publications were retrieved for screening by the literature search, of which 48 studies were screened out after review of abstracts. Of these, 17 studies [10], [14], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49] met the inclusion criteria for our meta-analysis, one [37] of which included two trials. Therefore, a total of 18 trials with a combined subject population of 8779 adult patients undergoing tracheal

Discussion

Massive landmark improvements have been made and general anaesthesia is now regarded as a safe procedure. However, rare, difficult airway management still occurs and it prompts increased risk of morbidity and mortality - especially when not anticipated. Since failed endotracheal intubation is a principal cause of morbidity and mortality in anesthetized patients [1], an accurate test to predict difficult intubation before induction of anaesthesia or laryngoscopy is essential. No ideal

Acknowledgements

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

The authors declare no conflict of interests.

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Spanish Society of Anesthesiology, Reanimation and Pain Therapy (SEDAR) Spanish Society of Emergency and Emergency Medicine (SEMES) and Spanish Society of Otolaryngology, Head and Neck Surgery (SEORL-CCC) Guideline for difficult airway management. Part I
2024, Revista Espanola de Anestesiologia y Reanimacion
La sección de Vía Aérea de la Sociedad Española De Anestesiología, Reanimación y Terapéutica del Dolor (SEDAR), la Sociedad Española de Medicina de Urgencias y Emergencias (SEMES) y la Sociedad Española de Otorrinolaringología y Cirugía de Cabeza y Cuello (SEORL-CCC) presentan la Guía para el manejo integral de la vía aérea difícil en el paciente adulto. Sus principios están focalizados en el factor humano, los procesos cognitivos para la toma de decisiones en situaciones críticas y la optimización en la progresión de la aplicación de estrategias para preservar una adecuada oxigenación alveolar con el objeto de mejorar la seguridad y la calidad asistencial. El documento proporciona recomendaciones basadas en la evidencia científica actual, herramientas teórico/educativas y herramientas de implementación, fundamentalmente ayudas cognitivas, aplicables al tratamiento de la vía aérea en el campo de la anestesiología, cuidados críticos, urgencias y medicina prehospitalaria. Para ello se realizó una amplia búsqueda bibliográfica según las directrices PRISMA-R y se analizó utilizando la metodología GRADE. Las recomendaciones se formularon de acuerdo con esta metodología. Las recomendaciones de aquellas secciones con evidencia de baja calidad se basaron en la opinión de expertos mediante consenso alcanzado a través de un cuestionario Delphi.
The Airway Management section of the Spanish Society of Anesthesiology, Resuscitation, and Pain Therapy (SEDAR), the Spanish Society of Emergency Medicine (SEMES), and the Spanish Society of Otorhinolaryngology and Head and Neck Surgery (SEORL-CCC) present the Guide for the comprehensive management of difficult airway in adult patients. Its principles are focused on the human factor, cognitive processes for decision-making in critical situations, and optimization in the progression of strategies application to preserve adequate alveolar oxygenation in order to enhance safety and the quality of care. The document provides evidence-based recommendations, theoretical-educational tools, and implementation tools, mainly cognitive aids, applicable to airway management in the fields of anesthesiology, critical care, emergencies, and prehospital medicine. For this purpose, an extensive literature search was conducted following PRISMA-R guidelines and was analyzed using the GRADE methodology. Recommendations were formulated according to the GRADE methodology. Recommendations for sections with low-quality evidence were based on expert opinion through consensus reached via a Delphi questionnaire.
Distance from skin to epiglottis measurement with ultrasonography as a predictor of difficult laryngoscopy: A diagnostic test accuracy meta-analysis
2023, Trends in Anaesthesia and Critical Care
The studies investigating distance from the skin to epiglottis measurements by ultrasonography (US-DSEM) for prediction of difficult laryngoscopy are inconclusive and non-standardised.
We aimed to assess the diagnostic test accuracy (DTA) of US-DSEM relative to Cormack Lehane 3–4 for diagnosing difficult laryngoscopy using a meta-analysis method.
Strict inclusion criteria were used to provide clear definition of how to measure US-DSEM. PubMed, Cochrane Library, Embase and Google Scholar were searched for papers published between January 2005 and March 2021 to perform a systematic review and DTA meta-analysis. Publications reporting data on US-DSEM in difficult laryngoscopy prediction in adults with normal airway were included. Exclusions were obese or pregnant patients and patients with difficult airway predictors and those in which the measurements were made in a position other than supine and neutral positions. The pooled sensitivity, specificity, positive/negative likelihood ratios (PLR/NLR), diagnostic odds ratio (DOR), and area under the hierarchic summary receiver operating characteristics curve (AU-HSROC) were determined.
1244 patients from nine studies were included. Pooled sensitivity: 0.68 (95%CI 0.39–0.87), specificity: 0.76 (95%CI 0.68–0.83), PLR: 2.87 (95%CI 2.20–3.73), NLR: 0.42 (%95CI 0.20–0.87), DOR: 6.80 (95%CI 2.72–17.3), and AU-HSROC: 0.79 (0.75–0.82) were the results. No threshold effect (r = 0.53, p = 0.137) and publication bias (p = 0.540) existed.
This meta-analysis showed that US-DSEM measured with linear probe placed transversely at the thyrohyoid membrane level with midline approach and neutral head position is accurate and has diagnostic value in predicting difficult laryngoscopy. However, its sensitivity and specificity are not sufficient to replace clinical tests.
Neck ultrasound to improve risk assessment for difficult tracheal intubation in the operating room: The TUBECHO case-control prospective observational pilot study
2021, Journal of Clinical Anesthesia
Preoperative assessment of the difficult airway in otolaryngology – implications for operative technique and airway management
2020, Operative Techniques in Otolaryngology - Head and Neck Surgery
Citation Excerpt :
Various measured parameters such as anterior cervical soft tissue thickness, visualization of the hyoid bone, pre-epiglottic space thickness, size of tongue in relation to oral volume, thickness of the lateral pharyngeal wall, hyomental distance ratio, and a combination of some of the above parameters, have claimed to be predictive of the difficult airway and DBMV.31–33 A meta-analysis by Ji et al found that computed tomography (CT), X-ray, and US had a better diagnostic value than MM scores.33 They found that the diagnostic odds ratio of US to be superior to other clinical tests except for the upper bite test class III, which appears to be on a par.8
Despite a plethora of articles describing airway assessment, there is no magic bullet for difficult airway evaluation. Statistical validation of scoring systems and radiological evaluations appear to be elusive. The reason for our inability to reliably assess every airway is complex. Every airway has a subset of subtly different anatomical variables and when taken in totality may result in difficult bag mask ventilation or difficult intubation. Simply looking at 5-12 risk factors may not be relevant or adequate for an individual. Another possibility is that anatomical measurements of the airway may be difficult to standardize as exact anthropometrical landmarks may not be clear. And combined with the fact that unanticipated difficult bag mask ventilation or difficult intubation is rare (5.8%) some of the older studies may have been underpowered.
A positive spin from extensive airway assessment research, coupled with heightened awareness of failed airway management and improved training and airway equipment, is that the need for invasive surgical airways has decreased.
The future development of more sophisticated data algorithms could provide software whereby digital imaging techniques could be readily validated. Digital imaging is a technique whereby photographs or contrast-enhanced computerized axial tomogram scans are collated into 3D images, resulting in detailed customized evaluation. Until then, adherence to comprehensive, systematic, and rigid clinical approaches as described in this narrative review is obligatory, and complacency when managing any airway should be avoided.
Airway sonography fails to detect difficult laryngoscopy in an adult Veteran surgical population
2019, Trends in Anaesthesia and Critical Care
Citation Excerpt :
There is emerging literature on the utility of ultrasonography in airway assessment and management [3–7]. Among imaging modalities, sonography is comparable to the gold standard of computed tomography in evaluating airway structures [8–10]. A variety of studies have emerged with increasing frequency over the last few years.
To evaluate ultrasound's utility to detect difficult laryngoscopy in a preoperative setting.
This single-site, prospective, cross-sectional, within-subjects study was performed at a Veterans Affairs Medical Center with 144 subjects. The sonographic independent variables included sonographic hyomental distance (HMD) and anterior neck thicknesses at the hyoid bone (HB), thyrohyoid membrane (THM), and vocal cords (VC). Additional independent variables were standard airway indicators of BMI, neck circumference, obstructive sleep apnea, snoring, abnormal upper teeth, jaw mobility, interincisor gap, Mallampati score, thyromental distance and neck range of motion. The outcome variable was the modified Cormack-Lehane Grade (CLG).
There was no significance found among the four sonographic measurements or their derived ratios in predicting difficult laryngoscopy. Correlation analysis between the sonographic measurements did find significance of the HMD:HB (p = 0.040) and the HB:THM (p = 0.44) ratios. However these ratios had a weak correlation at −0.172 and −0.168 respectively. Standard airway indicators did not demonstrate significance in predicting the difficult airway, sans obese patient with neck circumference (p = 0.016).
This study demonstrated ultrasonography in predicting difficult laryngoscopy lacked utility. Ultrasound utilization as an efficacious means of difficult airway assessment requires further research with a larger sample size. Further studies using sonography on those patients with known difficult airways may provide data to determine if ultrasound has utility in predicting difficult laryngoscopy.
Ultrasonography of the airway to identify patients at risk for difficult tracheal intubation: Are we there yet?
2018, Journal of Clinical Anesthesia

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¹: These two authors contributed equally to this work and should be considered co-first authors.

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Original ContributionDiagnostic accuracy of radiology (CT, X-ray, US) for predicting difficult intubation in adults: A meta-analysis

Highlights

Abstract

Objective

Methods

Results

Conclusions

Introduction

Section snippets

Search strategy

Literature search and characteristics of included studies

Discussion

Acknowledgements

Br J Anaesth

Br J Anaesth

Br J Anaesth

Br J Anaesth

Br J Anaesth

Int J Surg

Comput Stat Data Anal

J Clin Epidemiol

Br J Oral Maxillofac Surg

J Crit Care

Br J Anaesth

Ann Emerg Med

Prediction of difficult tracheal intubation: time for a paradigm change

Anesthesiology

Bedside predictors of difficult intubation: a systematic review

Minerva Anestesiol

Difficult tracheal intubation: a retrospective study

Anaesthesia

A clinical sign to predict difficult tracheal intubation: a prospective study

Can Anaesth Soc J

Predicting difficult intubation in apparently normal patients: a meta-analysis of bedside screening test performance

Anesthesiology

Predictive models for difficult laryngoscopy and intubation. A clinical, radiologic and three-dimensional computer imaging study

Can J Anaesth

Ultrasonography for clinical decision-making and intervention in airway management: from the mouth to the lungs and pleurae

Insights Imaging

The use of ultrasound in obstetric anesthesia

Curr Opin Anaesthesiol

The feasibility of CT rebuilding three-dimensional images of upper airway to predict difficult airway

Chin J Oral Maxillofac Surg

Meta-analysis of diagnostic and screening test accuracy evaluations: methodologic primer

AJR Am J Roentgenol

Airway Management, Miller’s Anesthesia

Definition and incidence of the difficult airway, airway management

Airway management, clinical anesthesia

Airway, rosen's emergency medicine: concepts and clinical pratice

Airway management and endotracheal intubation, Irwin and Rippe's intensive care medicine

Difficult tracheal intubation in obstetrics

Anaesthesia

Original Contribution
Diagnostic accuracy of radiology (CT, X-ray, US) for predicting difficult intubation in adults: A meta-analysis