Effectiveness of simplified predictive intubation difficulty score and thyromental height in head and neck surgeries: an observational study / Eficácia do escore simplificado preditivo de dificuldade de intubação e da altura tiromentoniana em cirurgias de cabeça e pescoço: estudo observacional

Abstract Background and objectives: In this study, we aimed to investigate the predictive value of different airway assessment tools, including parts of the Simplified Predictive Intubation Difficulty Score (SPIDS), the SPIDS itself and the Thyromental Height Test (TMHT), in intubations defined as difficult by the Intubation Difficulty Score (IDS) in a group of patients who have head and neck pathologies. Methods: One hundred fifty-three patients who underwent head and neck surgeries were included in the study. The Modified Mallampati Test (MMT) result, Thyromental Distance (TMD), Ratio of the Height/Thyromental Distance (RHTMD), TMHT, maximum range of head and neck motion and mouth opening were measured. The SPIDSs were calculated, and the IDSs were determined. Results: A total of 25.4% of the patients had difficult intubations. SPIDS scores >10 had 86.27% sensitivity, 71.57% specificity and 91.2% Negative Predictive Value (NPV). The results of the Receiver Operating Curve (ROC) analysis for the airway screening tests and SPIDS revealed that the SPIDS had the highest area under the curve; however, it was statistically similar to other tests, except for the MMT. Conclusions: The current study demonstrates the practical use of the SPIDS in predicting intubation difficulty in patients with head and neck pathologies. The performance of the SPIDS in predicting airway difficulty was found to be as efficient as those of the other tests evaluated in this study. The SPIDS may be considered a comprehensive, detailed tool for predicting airway difficulty.

Resumo Justificativa e objetivos: Neste estudo, avaliamos o valor preditivo de diferentes ferramentas de avaliação das vias aéreas, incluindo componentes do Escore Simplificado Preditivo de Intubação Difícil (ESPID), o próprio ESPID e a Medida da Altura Tireomentoniana (MATM), em intubações definidas como difícies pelo Escore de Dificuldade de Intubação (EDI) em um grupo de pacientes com patologia de cabeça e pescoço. Método: Incluímos no estudo 153 pacientes submetidos a cirurgia de cabeça e pescoço. Coletamos os resultados do Teste de Mallampati Modificado (TMM), Distância Tireomentoniana (DTM), Razão Altura/Distância Tireomentoniana (RADTM), MATM, amplitude máxima de movimentação da cabeça e pescoço e da abertura da boca. Os ESPIDs foram calculados e os EDIs, determinados. Resultados: Observamos intubação difícil em 25,4% dos pacientes. Os escores de ESPID > 10 tiveram sensibilidade de 86,27%, especificidade de 71,57% e valor preditivo negativo de 91,2% (VPN). O resultado da análise da curva de operação do receptor (curva ROC) para os testes de avaliação das vias aéreas e ESPID mostrou que o ESPID tinha a maior área sob a curva; no entanto, foi estatisticamente semelhante a outros testes, exceto para o TMM. Conclusões: O presente estudo demonstra o uso prático do ESPID na previsão da dificuldade de intubação em pacientes com patologia de cabeça e pescoço. O desempenho do ESPID na predição de via aérea difícil mostrou-se tão eficiente quanto os demais testes avaliados neste estudo. O ESPID pode ser considerado ferramenta abrangente e detalhada para prever via aérea difícil.

Is Acromio-Axillo-Suprasternal Notch Index a Reliable Test to Predict Difficult Tracheal Intubation in Adults in Supine Position - an Observational Study

Introduction: The applicability of the Modified Mallampatitest in supine patients is doubtful. We undertook this studyto evaluate the efficacy of acromio-axillo-suprasternal notchindex (AASI) for predicting difficult intubation and tocompare it with modified Mallampati test in supine position(MMT-S).Material and Methods: This prospective observationalstudy included 200 patients of American Society ofAnaesthesiologist (ASA) physical status I and II ofeither gender, aged 18-60 years. Patients with anatomicalabnormalities involving head and neck, pregnant, edentulousand BMI>35Kg/m2 were excluded. AASI and MMT-S wereassessed preoperatively. Direct laryngoscopy was performedby an experienced anaesthesiologist blinded to the result ofairway assessment tests. Cormack Lehane grade (CL grade)and number of attempts to successful intubation were noted.Primary objective was to assess AASI as predictor of difficultvisualisation of larynx (DVL) and secondary objective was tocompare it with MMT-S. Statistical analysis- McNamer testwas used to compare sensitivity and specificity of both themethods. Comparison of Area under Curve(AUC) of both themethods was performed.Results: AASI was 92% sensitive and 97.71% specificin predicting difficult intubation whereas sensitivity andspecificity of MMT-S was 76% and 84.57% respectively. AreaUnder Curve (AUC) of AASI was 0.97 with cut-off value>0.49 as a predictor of difficult intubation.Conclusion: AASI with cut off value >0.49 has highersensitivity and positive predictive value and is better inpredicting difficult airway in supine patients as compared toMMT-S.

Evaluation of bedside tests and proposal of a model for predicting difficult laryngoscopy: an observational prospective study / Avaliação de testes à beira leito e proposta de modelo para prever laringoscopia difícil: estudo prospectivo observacional

Abstract Background and objectives: The prediction of difficult laryngoscopy is based on tests that assess anatomic characteristics of face and neck. We aimed to identify the most accurate tests and propose a multivariate predictive model. Methods: This prospective observational study included 1134 patients. Thyromental Distance (TMD), Sternomental Distance (STMD), Ratio of Height-to-Thyromental Distance (R-H/TMD), Neck Circumference (NC), Ratio of Neck Circumference-to-Thyromental Distance (R-NC/TMD), Hyomental Distance with head in Neutral Position (HMD-NP) and at Maximal Extension (HMD-HE), Ratio of Hyomental Distance at Maximal head extension-to-hyomental distance in neutral position (R-HMD), Mallampati Class (MLC), Upper Lip Bite Test (ULBT), Mouth Opening (MO) and Head Extension (HE) were assessed preoperatively. A Cormack-Lehane Grade ≥ 3 was defined as Difficult Laryngoscopy. Sensitivity, specificity, positive and negative predictive values were assessed for all tests. Multivariate analysis with logistic regression was used to create the predictive models. Results: A model incorporating MLC, ULBT, HE, HMD-HE and R-NC/TMD showed high prognostic accuracy; x2(5) = 109.12, p < 0.001, AUC = 0.86, p < 0.001). Its sensitivity, specificity and negative predictive value were 82.3%, 74.8% and 97.4%, respectively. A second model including two measurements not requiring patient's cooperation (R-NC/TMD and HMD-HE) exhibited good prognostic performance; x2(2) = 63.5, p < 0.001, AUC = 0.77, p < 0.001. Among single tests, HE had the highest sensitivity (78.5%) and negative predictive value (96%). Conclusions: A five-variable model incorporating MLC, ULBT, HE, HMD-HE and R-NC/TMD showed satisfyingly high predictive value for difficult laryngoscopy. A model including R-NC/TMD and HMD-HE could be useful in incapable patients. The most accurate single predictor was HE.

Resumo Justificativa e objetivos: A previsão de laringoscopia difícil se baseia em testes que avaliam as características anatômicas da face e pescoço. Nosso objetivo foi identificar os testes mais precisos e propor modelo preditivo multivariado. Método: Estudo observacional prospectivo incluiu 1134 pacientes e avaliou no pré-operatório: Distância Tireomentoniana (DTM), Distância Esternomentoniana (DEM), razão Altura-Distância Tireomentoniana (A/DTM), Circunferência Cervical (CC), razão Circunferência Cervical-Distância Tireomentoniana (CC/DTM), Distância Hiomentoniana com a cabeça na Posição Neutra (DHM-PN) e em Extensão Máxima (DHM-EM), razão Distância Hiomentoniana com Cabeça em Extensão Máxima/Distância Hiomentoniana na posição Neutra (DHME/DHMN), Classe Mallampati (CML), Teste da Mordida do Lábio Superior (TMLS), Abertura da Boca (AB) e Extensão da Cabeça (EC). Grau Cormack-Lehane ≥ 3 foi definido como Laringoscopia Difícil. A sensibilidade, especificidade, valores preditivos positivo e negativo foram avaliados para todos os testes. A análise multivariada com regressão logística foi usada para criar modelos preditivos. Resultados: Um modelo incorporando CML, TMLS, EC, DHM-EM e CC/DTM demonstrou alta precisão prognóstica (x2(5) = 109,12, p < 0,001, AUC = 0,86, p < 0,001). A sensibilidade, especificidade e valor preditivo negativo foram 82,3%, 74,8% e 97,4%, respectivamente. Um segundo modelo incluindo duas medidas que não necessitavam da cooperação do paciente (CC/DTM e DHM-EM) demonstrou bom desempenho prognóstico (x2 (2) = 63,5; p < 0,001; AUC = 0,77, p < 0,001). Entre os testes individuais, EC teve a maior sensibilidade (78,5%) e valor preditivo negativo (96%). Conclusões: O modelo de cinco variáveis incorporando CML, TMLS, EC, DHM-EM e CC/DTM mostrou valor preditivo satisfatoriamente alto para laringoscopia difícil. Um modelo que incluísse CC/DTM e DHM-EM poderia ser útil em pacientes com incapacidade. O preditor individual mais preciso foi EC.

Evaluation of Modified Mallampati Score with Neck Circumference and Thyromental Distance to Predict Difficult Intubation in Non-obese Patients

Introduction: Preoperative diagnostic validity of airwayassessment help for prediction of difficult airway. Severalmodels were established for prediction of difficult intubation.In this study, we aim to predict difficult intubation in nonobese patients from various airway predictive indices suchas modified mallampati grade, neck movement (NM), neckcircumference (NC), thyrometal distance (TM), NC/TMD.Material and Methods: Total 121 patients with 18-72 yearsof age, ASA grade I or II, scheduled for elective surgerythat required general anaesthesia. Difficulty of intubationwas assessed using the IDS for each non-obese patient. Thestudy population was divided into two groups Easy (IDS <5)and Difficult intubation (IDS ≥5). Preoperative assessmentsincluded Mouth Opening (MO), modified mallampati grade,neck movement (NM), neck circumference (NC), thyrometaldistance (TM), NC/TMD. Multivariate analysis was usedto predict independent risk factors. Receiver OperatingCharacteristic Curve analysis (ROC analysis) was performedfor the airway assessment tests. The area under curve (AUC)was calculated.Results: The weight (59.74±7.76 kg and 65.00±5.92 kg)and BMI (21.51±1.79 and 23.8157±1.09) were significantlydifferent in between easy and difficult intubation. TheMouth Opening, NC, TMD, and NC/TMD were significantlyindependent risk factor for difficult intubation. NC/TMDwas showed higher sensitivity, specificity, positive predictivevalue (PPV) and a negative predictive value (NPV) with thirdlarge area under the curve (AUC) on the ROC curve.Conclusions: This study shows that the NC/TMD ratio canbe considered as a better predictor of difficult intubation innon-obese patients.

Effect of the LEMON method in predicting patients with difficult airway / 临床麻醉学杂志

Objective To evaluate the effect of the LEMON method in predicting difficult air-way.Methods A total of 1 528 patients scheduled for elective surgery requiring tracheal intubation under general anaesthesia,680 males and 848 females,aged 18-83 years,ASA physical status Ⅰ orⅡ,were enrolled in the study.We used the LEMON method to assess airway conditions before an-aesthesia and recorded the scores.The primary end point was difficult tracheal intubation.The sec-ondary end point was difficult laryngoscopy.Receiver operating characteristic (ROC)curve analysis and the area under the curve (AUC)were used to evaluate the clinical effect of the LEMON mothod. Results There were 37 cases with difficult tracheal intubation and 106 cases with difficult laryngosco-py.The incidence of difficult tracheal intubation and difficult laryngoscopy were 2.4% and 6.9%,re-spectively.The area under the curve of the LEMON method for predicting difficult laryngoscopy and difficult tracheal intubation were 0.884 (95% CI 0.867-0.899)and 0.934 (95% CI 0.921-0.946), respectively.Conclusion The LEMON method has good clinical effect in predicting difficult airway.

Evaluation of Modified Cormack-Lehane Scoring System in Indian Population.

Background: The usefulness of modified Cormack-Lehane scoring system (MCLS) used for laryngoscopy was introduced and used extensively Western population. This study was undertaken for evaluation of modified Cormack-Lehane scoring system in Indian population. Methods: 198 patients of more than 18 years of age requiring tracheal intubation were evaluated with preoperative airway predictors, the modified Mallampati test and thyromental distance (TMD). Result: The larynx was difficult to visualize (Cormack and Lehane grades IIIB and IV) in 18 / 198 (9.09 %) patients. No failed tracheal intubations occurred in any of the 18 cases. Conclusion: The Mallampati classification was associated with good predictive value for 3B and 4 of modified Cormack-Lehane scoring system. The MCLS better delineates the difficulty experienced during laryngoscopy than the original Cormack-Lehane grading.

Effect of Head Extension Angle to Glottis Exposure : A Simulation Evaluation Based on CT Reconstruction Images of Upper Airway / 医学研究杂志

Objective To investigate the effect of head extension angle to glottis exposure by using three-dimensional CT reconstruction sagittal plane images of upper airway.Methods There were 80 patients,aged 7-78 years old,who had been scanned by helical CT in the head and neck.Reconstructed images were obtained by AW4.4 workstation and the following parameter was measured:angle α(A0 group),the angle created by the upper central incisor and root of epiglottis(angular vertex) and midpoint of glottis.Reconstructed images were printed according to the actual size of human body in a ratio of 1∶ 1,then the images were cut off from the upper central incisor to root of epiglottis by a section of arcs.Increasing the degree of angle α by clockwise to hypothetically increase the angle of head extension.The glottis was exposed by using a paper-made laryngoscope(Macintosh) model,and the success rate of glottis exposure was recorded when the degree of angle α was respectively increased 10°(A10 group),20°(A20 group),and 30°(A30 group).Results Compared with A0 group,the success rate of glottis exposure increased significantly in A10 group,A20 group and A30 group.The success rate of glottis exposure in A20 group and A30 group was significantly higher than A10 group.Compared with A20 group,the success rate of glottis exposure obviously increased in A30 group.Conclusion Based on CT reconstruction images of upper airway,we can analog study the effect of head extension angle to glottis exposure.

A randomized trial to assess the utility of preintubation adult fiberoptic bronchoscope assessment in patients for thoracic surgery requiring one‑lung ventilation.

Background: Confirmation of placement of Double lumen endobronchial tubes (DLETT) and bronchial blockers (BBs) with the pediatric fiberoptic bronchoscope (FOB) is the most preferred practice worldwide. Most centers possess standard adult FOBs, some, particularly in developing countries might not have access to the pediatric‑sized devices. We have evaluated the role of preintubation airway assessment using the former, measuring the distance from the incisors to the carina and from carina to the left and right upper lobe bronchus in deciding the depth of insertion of the lung isolation device. Methods: The study was a randomized, controlled, double‑blind trial consisting of 84 patients (all >18 years) undergoing thoracic surgery over a 12‑month period. In the study group (n = 38), measurements obtained during FOB with the adult bronchoscope decided the depth of insertion of the lung isolation device. In the control group (n = 46), DLETTs and BBs were placed blindly followed by clinical confirmation by auscultation. Selection of the type and size of the lung isolation device was at the discretion of the anesthesiologist conducting the case. In all cases, pediatric FOB was used to confirm accurate placement of devices. Results: Of 84 patients (DLETT used in 76 patients; BB used in 8 patients), preintubation airway measurements significantly improved the success rate of optimal placement of lung isolation device from 25% (11/44) to 50% (18/36) (P = 0.04). Our incidence of failed device placement at initial insertion was 4.7% (4/84). Incidence of malposition was 10% (8/80) with 4 cases in each group. The incidence of suboptimal placement was lower in the study group at 38.9% (14/36) versus 65.9% (29/44). Conclusions: Preintubation airway measurements with the adult FOB reduces airway manipulations and improves the success rate of optimal placement of DLETT and BB.

Predictors of Intubation in Children.

Objective To estimate the relation of mentohyoid, thyromental and sternomental distances to height, weight and age of children with normal airway. Methods We carried out a prospective, double blind pilot study in 400 children posted for elective surgery to measure mentohyoid, thyromental and sternomental distances preoperatively followed by intra-op evaluation of intubation using Cormack and Lehane grading. Results On assessing the contribution of age, height and weight to predict mentohyoid, thyromental and sternomental distances in children, the best predictor was found to be height (p=0.001)followed by age (p=0.04)of the patient. Conclusion We have derived simple formulae to predict mentohyoid, thyromental and sternomental distances relevant to airway based on height and age of children.