The Prediction of Difficult Intubation

Preparation of the patient and the airway for awake intubation

Awake intubation is usually performed electively in the presence of a difficult airway. A detailed airway examination is time-consuming and often not feasible in an emergency. A simple 1-2-3 rule for airway examination allows one to identify potential airway difficulty within a minute. A more detailed airway examination can give a better idea about the exact nature of difficulty and the course of action to be taken to overcome it. When faced with an anticipated difficult airway, the anaesthesiologist needs to consider securing the airway in an awake state without the use of anaesthetic agents or muscle relaxants. As this can be highly discomforting to the patient, time and effort must be spent to prepare such patients both psychologically and pharmacologically for awake intubation. Psychological preparation is best initiated by an anaesthesiologist who explains the procedure in simple language. Sedative medications can be titrated to achieve patient comfort without compromising airway patency. Additional pharmacological preparation includes anaesthetising the airway through topical application of local anaesthetics and appropriate nerve blocks. When faced with a difficult airway, one should call for the difficult airway cart as well as for help from colleagues who have interest and expertise in airway management. Preoxygenation and monitoring during awake intubation is important. Anxious patients with a difficult airway may need to be intubated under general anaesthesia without muscle relaxants. Proper psychological and pharmacological preparation of the patient by an empathetic anaesthesiologist can go a long way in making awake intubation acceptable for all concerned.

The laryngeal lift: a method to facilitate endotracheal intubation

STUDY OBJECTIVE

To assess the efficacy of the "laryngeal lift" maneuver in improving laryngoscopic visualization to facilitate endotracheal intubation.

DESIGN

Blinded study.

SETTING

Operating room at Meridia Huron Hospital.

PATIENTS

305 patients receiving general anesthesia for elective surgery requiring intubation. (Five patients were eliminated from the study because we elected to intubate these patients awake and sedated.)

INTERVENTIONS

Following induction of anesthesia and paralysis with muscle relaxants, laryngoscopic views of each patient were evaluated by the laryngoscopist before and after the laryngeal lift was performed by an anesthesiologist assisting the laryngoscopist. Each patient served as his or her own control group. The anesthesiologist was blinded to the results obtained by the laryngoscopist. All Grade I laryngoscopic views were eliminated (198 patients). Five patients were eliminated on the basis of obesity or atlantoaxial subluxation. The laryngeal lift was performed on the remaining 102 patients, representing Grade II to Grade V laryngoscopic views.

MEASUREMENTS AND MAIN RESULTS

A modification of the original classification of laryngoscopic views by Cormack and Lehane was used: Grade I = full view of glottis; Grade II = only posterior commissure visible; Grade III = arytenoids visible; Grade IV = epiglottis visible; Grade V = no glottic structure visible. In 98 of 102 cases (96%), the maneuver improved visualization by at least 1 grade. There was no evidence of change in the 4 remaining cases.

CONCLUSIONS

The laryngeal lift should be part of the anesthesiologists' armamentarium in helping the laryngoscopist who is faced with Grades II, III, IV, and V laryngoscopic views to enhance visualization of the larynx and thus facilitate endotracheal intubation.