Difficult intubation and extubation in adult anaesthesia.

OBJECTIVE: To provide an update to French guidelines about "Difficult intubation and extubation in adult anaesthesia 2006". DESIGN: A consensus committee of 13 experts was convened. A formal conflict-of-interest (COI) policy was developed at the onset of the process and enforced throughout. The entire guidelines process was conducted independent of any industry funding. The authors were advised to follow the principles of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to guide assessment of quality of evidence. The potential drawbacks of making strong recommendations in the presence of low-quality evidence were emphasized. Few recommendations were ungraded. METHODS: The panel focused on 6 questions: 1) Why must oxygen desaturation be avoided during intubation and what preoxygenation and oxygenation techniques should be used to prevent it? 2) Should videolaryngoscopes be used instead of standard laryngoscopy with or without a long stylet to achieve a better success rate of intubation after the first attempt during anticipated difficult intubation off fiberoptic intubation? 3) Should TCI or target controlled inhalation anaesthesia (TCIA) be used instead of bolus sedation for airway control in the event of suspected or proven difficulty in a patient spontaneously breathing? 4) What mode of anaesthesia should be performed in patients with difficult intubation criteria and potentially difficult mask ventilation? 5) In surgical patients, what criteria predict difficulties encountered during postoperative tracheal extubation? 6) Should decision trees and algorithms be employed to direct decision-making for the management of difficult intubation, whether foreseen or not? (based on the information from the preceding five issues). Population, intervention, comparison, and outcomes (PICO) questions were reviewed and updated as needed, and evidence profiles were generated. The analysis of the literature and the recommendations were then conducted according to the GRADE® methodology. RESULTS: The SFAR Guideline panel provided 13 statements on difficult intubation and extubation in adult anaesthesia. After two rounds of discussion and various amendments, a strong agreement was reached for 99% of recommendations. Of these recommendations, five have a high level of evidence (Grade 1±), 8 have a low level of evidence (Grade 2±). No recommendation was provided for one question. CONCLUSIONS: Substantial agreement exists among experts regarding many strong recommendations for the best care of patients with difficult intubation and extubation in adult anaesthesia.

Rescue transtracheal jet ventilation during difficult intubation in patients with upper airway cancer.

INTRODUCTION: The failure rates of intubation and/or mask ventilation are higher in patients with neck or upper airway disease. To ensure oxygenation, rescue trans-tracheal jet ventilation (RTTJV) may be used. In this critical situation, a high rate of complications has been reported. The aim of this study was to report RTTJV performed by a jet ventilator with an end-expiratory pressure control in an experienced institution. PATIENTS AND METHODS: From a computerised database of 63,905 anaesthesia cases, the anaesthetic reports of patients who underwent emergency RTTJV during intubation were studied retrospectively. The following information were analysed: anaesthetic procedures, data from the monitoring: lowest SpO2, duration of SpO2<90%, and complications. Success of emergency RTTJV was defined when SpO2 was>90% under jet ventilation. RESULTS: RTTJV was used in 31 patients, of whom 26 had upper airway cancer, (pre-treatment, n=9, post-treatment, n=17). Difficult intubation was anticipated in 15 out of 31 cases including six fiber-optic-aided intubations under spontaneous ventilation. RTTJV was effective in all cases with quick restoration of oxygenation (SpO2>90%). During jet ventilation, final airway control was performed either by oral intubation (n=25) or tracheotomy (n=1) in a short delay (mean: 8.1±1.7min). Subcutaneous emphysema was observed in one case without pneumothorax. CONCLUSION: RTTJV with end-expiratory pressure control allowed oxygenation during difficult intubation, with a low rate of complications.

Preoxygenation and general anesthesia: a review.

Because intubation can potentially become a lengthy procedure, the risk of arterial oxygen (O2) desaturation during intubation must be considered. Preoxygenation should be routine, as oxygen reserves are not always sufficient to cover the duration of intubation. Three minutes of spontaneous breathing at FiO2=1 allows denitrogenation with FAO2 close to 95% in patients with normal lung function. Tolerable apnea time, defined as the delay until the SpO2 reaches 90%, can be extended up to almost 10 minutes after 3 minutes of classic preoxygenation. Eight deep breaths within 60 seconds allow a comparable increase in O2 reserves. For effectiveness, the equipment must be adapted and tightly fitted. Inadequate preoxygenation (FeO2 <90% after three minutes tidal volume breathing) is frequently observed. Predictive risk factors for inadequate pre-oxygenation share overlap with criteria predictive of difficult mask ventilation. In cases of respiratory failure, oxygenation can be improved by positive end expiration pressure or by pressure support. In morbidly obese patients, preoxygenation is enhanced in a seated position (25°) and by use of positive pressure ventilation. O2 can also be administered during the intubation procedure; techniques include pharyngeal O2, special oxygen mask, or even pressure support ventilation for patients with spontaneous ventilation or positive pressure ventilation to the facial mask for apneic patients. Clinicians (especially anesthesiologists trained in ENT and traumatology) must be prepared to handle life-threatening emergency situations by alternate methods including trans-tracheal ventilation. The availability of equipment and training are two essential components of adequate preparation.