Title: Comparison of Methods for Prediction of Difficult Laryngoscopy and Intubation
Authors: Dr Madhuri Pramod Lonikar, Dr Ramesh G. Pathak, Dr Nazima Memon
DOI: https://dx.doi.org/10.18535/jmscr/v5i2.42
Abstract
Aims and Objectives
(1) To evaluate and compare various methods to predict difficult laryngoscopy and intubation and their combinations for sensitivity, specificity, Positive predictive value
(2) To observe if the combinations could attain 100% predictability.
Background: Unexpected difficult laryngoscopy and intubation is a challenging condition for anesthesiologists, causing hazardous complications for patients including death. It is very important to anticipate such difficulty in patients with apparently normal airways. Difficult laryngoscopy is considered to be associated with difficult intubation. We conducted this study to evaluate and compare various tests to predict difficult laryngoscopy and intubation in terms of sensitivity, specificity and positive predictive value. We also compared the combinations of these tests to see if they could attain 100% predictability.
Materials and Methods: Patients’ airways were assessed in this study using four tests. These tests included Modified Mallampati test, Wilson risk-sum, Thyro-mental distance and Mento-Hyoid distance. The study was conducted in 265 ASA Grade I and II cases. Sensitivity, specificity and positive predictive value of the individual tests and their different combinations were compared.
Results: 80% sensitivity was seen with Modified Mallampatti test, Thyromental distance and Mento-hyoid distance when applied alone except Wilson risk-sum. Combination of Modified Mallampati test with either Thyro-mental distance or Mento-hyoid distance showed 100% Sensitivity. When Wilson risk-sum was applied with other three tests, sensitivity could not go beyond 90%. For positive predictive value, Mento-hyoid distance showed highest value but when combined with other tests, positive predictive value came down to 50%.
Conclusion: Modified Mallampati test is most simple bedside tests and can be easily performed even in bed ridden patients. Mento-hyoid distance is best predictor of difficult laryngoscopy in terms of sensitivity, specificity and positive predictive value. The predicting power of combination of these tests is more as compared to individual tests. Combination of Modified Mallampati with mento-hyoid distance is the best predictor among the combinations.
Keywords: Difficult Laryngoscopy, assessment of airway, sensitivity, specificity, positive predictive value.
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