Pre-operative voice evaluation as a hypothetical predictor of difficult laryngoscopy

We examined the potential for voice sounds to predict a difficult airway as compared with prediction by the modified Mallampati test. A total of 453 patients scheduled for elective surgery under general anaesthesia with tracheal intubation were studied. Five phonemes were recorded and their formants analysed. Difficult laryngoscopy was defined as the Cormack-Lehane grade 3 or 4. Univariate and multivariate logistic regression were used to examine the association between some variables (mouth opening, sternomental distance, modified Mallampati and formants) and difficult laryngoscopy. Difficult laryngoscopy was reported in 29/453 (6.4%) patients. Among five regression models evaluated, the model achieving better performance to predict difficult laryngoscopy, after a variable selection criteria (stepwise, multivariate) and included a modified Mallampati classification (OR 2.920; 95%CI 1.992-4.279; p < 0.001), first formant of /i/(iF1) (OR 1.003; 95%CI 1.002-1.04; p < 0.001), and second formant of /i/(iF2) (OR 0.998; 95%CI 0.997-0.998; p < 0.001). The receiver operating curve for a regression model that included both formants and Mallampati showed an area under curve of 0.918, higher than formants alone (area under curve 0.761) and modified Mallampati alone (area under curve 0.874). Voice presented a significant association with difficult laryngoscopy during general anaesthesia showing a 76.1% probability of correctly classifying a randomly selected patient. (AU)

Pre-operative voice evaluation as a hypothetical predictor of difficult laryngoscopy.

We examined the potential for voice sounds to predict a difficult airway as compared with prediction by the modified Mallampati test. A total of 453 patients scheduled for elective surgery under general anaesthesia with tracheal intubation were studied. Five phonemes were recorded and their formants analysed. Difficult laryngoscopy was defined as the Cormack-Lehane grade 3 or 4. Univariate and multivariate logistic regression were used to examine the association between some variables (mouth opening, sternomental distance, modified Mallampati and formants) and difficult laryngoscopy. Difficult laryngoscopy was reported in 29/453 (6.4%) patients. Among five regression models evaluated, the model achieving better performance to predict difficult laryngoscopy, after a variable selection criteria (stepwise, multivariate) and included a modified Mallampati classification (OR 2.920; 95%CI 1.992-4.279; p < 0.001), first formant of /i/(iF1) (OR 1.003; 95%CI 1.002-1.04; p < 0.001), and second formant of /i/(iF2) (OR 0.998; 95%CI 0.997-0.998; p < 0.001). The receiver operating curve for a regression model that included both formants and Mallampati showed an area under curve of 0.918, higher than formants alone (area under curve 0.761) and modified Mallampati alone (area under curve 0.874). Voice presented a significant association with difficult laryngoscopy during general anaesthesia showing a 76.1% probability of correctly classifying a randomly selected patient.

Combined spinal and epidural anaesthesia and maternal intrapartum temperature during vaginal delivery: a randomized clinical trial.

BACKGROUND: We determined the association between combined spinal-epidural (CSE) anaesthesia and an increase in maternal intrapartum temperature and intrapartum fever. METHODS: A randomized, open clinical trial was performed with 70 pregnant women, 35 receiving CSE and 35 receiving only non-pharmacological methods of pain relief during delivery. Association between CSE and changes in the patient's temperature, the risk of maternal fever, and other maternal and perinatal outcomes was determined at a 5% significance level. Number needed to harm (NNH) was calculated for maternal fever. RESULTS: Patients receiving CSE anaesthesia during vaginal delivery experienced a significant increase in intrapartum temperature and five (14%) developed fever, whereas no cases occurred in the group receiving only non-pharmacological methods of pain relief (P=0.027). None of the women who developed fever received antibiotics or were submitted to further investigation; however, all progressed without complication. No case of chorioamnionitis or any maternal or neonatal infection was detected. NNH for maternal fever was 7.0 (95% confidence interval: 3.8-51.9). CONCLUSIONS: The use of CSE is associated with a significant increase in maternal temperature and in the incidence of intrapartum maternal fever. However, the increase in maternal temperature does not appear to provoke any deleterious effects on the mother or child.