Avaliação do Escore de Wilson e do Teste de Mallampati modificado como preditores de difícil intubação orotraqueal: Estudo transversal / Evaluation of the Wilson risk-sum and the modified Mallampati Test as predictors of difficult orotracheal intubation: Cross-sectional study

INTRODUÇÃO: A consulta pré-anestésica é de extrema importância para o médico anestesiologista no planejamento do manejo das vias aéreas de pacientes sob o efeito de anestesia geral com intubação orotraqueal (IOT). OBJETIVO: Avaliar a sensibilidade, especificidade, valor preditivo positivo/negativo (VPP/VPN) de testes de predição de IOT difícil (Escore de Wilson - EW, e Teste de Mallampati modificado - TMM), em pacientes submetidos à anestesia geral, em hospital filantrópico do interior de Minas Gerais. MATERIAIS E MÉTODOS: Estudo descritivo transversal, por meio de fichas pré-anestésicas e transoperatórias, de pacientes submetidos à anestesia geral com IOT, entre os meses de janeiro (2019) e março (2020). RESULTADOS: Dos 440 pacientes, 56,1% necessitaram de IOT: média de idade de 49,9 anos (desvio padrão 18,6). A maioria foi classificada: TMM classe I e II; pontuação 0 a 2 no EW; distância esternomentoniana >12,5 cm, sugerindo IOT fácil. Apenas o TMM apresentou correlação com IOT difícil (p=0,045). Sensibilidade e especificidade dos testes respectivamente: TMM (54,6%;75,9%); EW (36,4% e 79,7%); baixo VPP (TMM: 9,5%; EW: 7,7%) e alto VPN (TMM: 97,3%; EW: 96,4%). Curva ROC: área sob a curva foi de TMM = 0,68; EW = 0,60. CONCLUSÃO: Apesar do TMM apresentar correlação significativa com a IOT difícil, não foi possível definir o melhor teste preditor. Ressaltamos que a sensibilidade e o VPP, de ambas as avaliações, ficaram abaixo daquilo que seria considerado adequado para um teste de rastreio e predição.

Introduction: A pre-anesthetic appointment is extremely important for the anesthesiologist when planning the management of the airways of patients under the effect of general anesthesia with orotracheal intubation (OTI). Objective: To evaluate the sensitivity, specificity, positive/ negative predictive value (PPV/NPV) of difficult OTI prediction tests (Wilson risk-sum ­ WRS, and Modified Mallampati Test - MMT) in patients undergoing general anesthesia in a philanthropic hospital in the countryside of the state of Minas Gerais. Materials and methods: Descriptive cross-sectional study using pre-anesthetic and transoperative records of patients submitted to general anesthesia with OTI between the months of January (2019) and March (2020). Results: Of the 440 patients, 56.1% required OTI: average age of 49.9 years (standard deviation 18.6). Most classified: MMT class I and II; score 0 to 2 on the WRS; sternomental distance greater than 12.5 cm, suggesting easy OTI. Only MMT showed statistical significance with difficult OTI (p=0.045). Sensitivity and specificity of the tests respectively: MMT (54.6%; 75.9%) WRS (36.4% and 79.7%) low PPV (MMT: 9.5%; WRS: 7.7%) and high NPV (MMT: 97.3%; WRS: 96.4%). ROC Curve: area under the curve was MMT = 0,68; WRS = 0,60. Conclusion: Although the MMT has a significant correlation with the difficult OTI, it was not possible to define the best predictor test. We emphasize that the sensitivity and PPV of both evaluations were below what would be considered adequate for a screening and prediction test.

Comparison and evaluation of various bedside tests to predict difficult endotracheal intubation.

Introduction: As difficult laryngoscopy is a multifactorial problem, therefore any preoperative assessment of difficult tracheal intubation should have high sensitivity and specificity and result in minimal false positive and false negative values. This study was conducted in an attempt to devise a method of predicting difficult intubation and to assess the reliability of six simple bedside tests to predict difficult intubation. Material and Methods: This double blind prospective study involved 100 adult patients posted for elective surgery under general anesthesia. The airways were assessed for modified Mallampati test, Thyromental Distance, Sternomental Distance, Inter incisor gap; Atlanto-Occipital joint extension and Upper Lip bite Test. The laryngoscopic view and difficulty of intubation were noted. The sensitivity, specificity, positive and negative predictive values were calculated. Results: No method either individual or in combination with others had 100% sensitivity. The Modified Mallampati test had 76% sensitivity. Upper Lip bite Test had 98.66% specificity. The combination of Modified Mallampati test and Inter incisor gap had 52% sensitivity and 86.66% specificity. Conclusion: The “composite intubation difficulty score” is an easy and reliable method of predicting difficult intubation.

The changes of the sternomental distance under general anesthesia and with increasing age

BACKGROUND: Because the sternomental distance (SMD) is evaluated in conscience patients and in the sitting position, this could change under general anesthesia, which is a state that the patient is unconscious and fully relaxed in the supine position. Increasing age also affects the SMD. We investigated the change in the SMD with the patients under general anesthesia and we also investigated the effect of age on the SMD. METHODS: A total of 108 patients were allocated to Group Y (20-30 yr), Group M (31-50 yr) and Group O (51-70 yr). The SMD, as measured when the patients were awake and sitting, was defined as baseline. The SMD was measured in the supine position, the shoulder-suppressed supine position, at the time of loss of consciousness (LOC), 4 min after vecuronium administration and in the sniffing position. The percent change of the SMD (%) was defined as (the baseline SMD - the measured SMD)/the baseline SMD x 100. RESULTS: Compared with the baseline, the SMD decreased significantly in the supine position, the shoulder-suppressed supine position, at the time of LOC, during neuromuscular blockade and in the sniffing position in all the groups. Group O showed a shorter SMD than did Groups Y and M for all the measurements. There was no significant difference in the percent change of the SMD between the groups. CONCLUSIONS: This study demonstrated that the SMD was significantly reduced by the supine position, the sniffing position, at the time of loss of consciousness and during neuromuscular blockade with the patient under general anesthesia and also with the increasing age of the patient.