Preoperative assessment for difficult intubation in general and ENT surgery: predictive value of a clinical multivariate risk index.

Several clinical multifactorial indexes have been described for predicting difficult laryngoscopy or intubation, or both, mostly in general surgery, and less frequently in ENT surgery. The objective of this study was to develop and validate a single clinical index for prediction of difficulty in tracheal intubation in both ENT and general surgery. We studied a population of 1200 consecutive ENT and general surgical patients. Clinical criteria were tested using univariate and multivariate analysis. Difficult intubation was defined as requiring unusual techniques. Logistic regression identified seven criteria as independent predictors of difficult tracheal intubation; previous history of difficult intubation; pathologies associated with difficult intubation; clinical symptoms of pathological airway; inter-incisor gap and mandible luxation; thyromental distance; head and neck movement; and Mallampati's modified test. Point values were assigned to each of these factors in proportion to regression coefficients representing the relative weight of each predictive intubation difficulty factor, the sum comprising the score. The best predictive threshold was chosen using a receiver operating characteristic curve. We then prospectively studied and validated the score in a population of 1090 consecutive ENT and general surgery patients. The sensitivity and specificity of the predictions were 94% and 96% in general surgery, 90% and 93% in non-cancer ENT surgery, and 92% and 66% in ENT cancer surgery, respectively.

[Proposal for a new multifactor screening score of difficult intubation in ORL and stomatognathic surgery: preliminary study]. / Proposition d'un nouveau score multifactoriel de dépistage de l'intubation difficile en chirurgie ORL et stomatologique: étude préliminaire.

This study assessed prospectively in 295 ENT adult patients the predictive value of clinical indicators for difficult intubation and of a new multifactorial score, established by the allocation of points (0, 3, 5 or 7) depending on the degree of presence of seven factors: pathology known to be associated with a difficult intubation, clinical signs of airways' pathology, inter-incisors gap and mandible's luxation, submental mandibular-thyroid distance, normal or short and broad neck, head and neck movements, and Mallampati's test. The incidence of difficult laryngoscopy was 14% and the use of particular techniques for tube insertion was required in 8% of patients. The presence of malformation or pathology often associated with a difficult intubation and the presence of functional signs of airways' pathology predict the difficulties of laryngoscopy and tracheal intubation with a good sensitivity and specificity. The analysis of the "Receiver Operating Characteristic curves" showed that a score higher or equal to 11 allows the prediction of difficult intubations with a sensitivity of 96% and a specificity of 90%.

[Low-concentration enflurane:study of anesthetic stability and quality of recovery]. / Enflurane à faible concentration: étude de la stabilité anesthésique et de la qualité du réveil.

The stability of anaesthesia and the quality of recovery obtained with low doses of enflurane were studied. Two groups of 20 patients operated for lumbar slipped disc were compared. The mean age and weight distribution of the two groups were not statistically different. Induction was the same in the two groups (diazepam, fentanyl, pancuronium and nitrous oxide). In one group, enflurane (0.4%) was added with controlled ventilation. Thiopentone was added if some spontaneous movements were observed, if arterial pressure and heart rate increased, and if the digital plethysmograph curve decreased. The quality of recovery was assessed by number-connection tests 1 and 2 h after the end of anaesthesia. Thiopentone was required five times in the group without enflurane, whilst it was never used in the group with enflurane. This difference was statistically significant (p less than 0.01) and showed a more important stability of anaesthesia when enflurane (0.4%) was used. No statistically significant difference was found in the recovery scores between the two groups 1 and 2 h after the end of anaesthesia. It was proposed that low doses of enflurane were sufficient to increase the effects of the other anaesthetic drugs without any residual effect on recovery. Low doses of enflurane could be used during anaesthesia induced with fentanyl and diazepam, giving better stability during anaesthesia without any pernicious effects on recovery.