Comparison of the Glidescope, the McGrath, the Airtraq and the Macintosh laryngoscopes in simulated difficult airways*.

SUMMARY: Several indirect laryngoscopes have recently been developed, but relatively few have been formally compared. In this study we evaluated the efficacy and the usability of the Macintosh, the Glidescope, the McGrath and the Airtraq laryngoscopes. Sixty anaesthesia providers (20 staff, 20 residents, and 20 nurses) were enrolled into this study. The volunteers intubated the trachea of a Laerdal SimMan manikin in three simulated difficult airway scenarios. In all scenarios, indirect laryngoscopes provided better laryngeal exposure than the Macintosh blade and appeared to produce less dental trauma. In the most difficult scenario (tongue oedema), the Macintosh blade was associated with a high rate of failure and prolonged intubation times whereas indirect laryngoscopes improved intubation time and rarely failed. Indirect laryngoscopes were judged easier to use than the Macintosh. Differences existed between indirect devices. The Airtraq consistently provided the most rapid intubation. Laryngeal grade views were superior with the Airtraq and McGrath than with the Glidescope.

Intravenous amiodarone or magnesium sulphate is not cost-beneficial prophylaxis for atrial fibrillation after coronary artery bypass surgery.

Our aims were to examine whether the administration of amiodarone or magnesium sulphate after coronary artery bypass graft surgery (CABG) could reduce the occurrence of atrial fibrillation, and to identify the risk factors associated with atrial fibrillation after CABG. Patients scheduled for elective CABG (n = 155) were allocated randomly, in a controlled double-blind study, to receive immediately after surgery a 72-h infusion of amiodarone (900 mg per 24 h), magnesium (4 g per 24 h) or placebo (0.9% NaCl; 50 ml per 24 h) intravenously. A 72-h Holter ECG was recorded concomitantly. The primary end-point was the prevention of atrial fibrillation; its onset was considered as prophylactic failure. An interim safety analysis was performed in 147 patients. The cumulative occurrence of atrial fibrillation was 27% in the placebo group, 14% in the amiodarone group (P = 0.14) and 23% in the magnesium group (P = 0.82). Although amiodarone delayed the onset of the first tachyarrhythmic episode (P = 0.02), it was associated with the need for longer periods of vasoactive drug infusion and invasive monitoring and a longer stay in the intensive care unit. Variables associated with the onset of atrial fibrillation were older age (odds ratio 1.9) and a plasma magnesium concentration at 24 h of less than 0.95 mmol litre-1 (odds ratio 6.7). Postoperative administration of amiodarone reduced the occurrence of atrial fibrillation after elective CABG surgery, but was associated with a longer duration of cardiovascular instability and longer need for intensive care; magnesium prophylaxis had no effect. Advanced age and a low plasma magnesium concentration are risk factors for postoperative atrial fibrillation.