[Propofol sedation allows awake intubation of the difficult airway with the Fastrach LMA]

Abstract

Purpose: To evaluate target controlled infusion anesthesia (TCI) with propofol for conscious intubation [(Ramsay score equal to 3 (RS 3)] through the Fastrach laryngeal mask airway (LMA).

Methods: 17 consenting and unpremedicated patients, who showed criteria for difficult intubation (score developed by Arne et al. > or = 11), were monitored and received supplemental oxygen. Propofol was administered by TCI, with successive targets of 0.6 and 1 microg x mL(-1), while the RS was evaluated: if = 3, LMA intubation was attempted, if < 3 the TCI was increased by steps of 0.2 microg x mL(-1) until an RS of 3 was reached. Local anesthesia (lidocaine 5%) of the oropharynx was carried out at 0.6 and 1 microg x mL(-1), together with local anesthesia of the nasopharynx at 1 microg x mL(-1). A standardized questionnaire evaluated memory of and satisfaction with the technique (score/10) on postoperative day 1.

Results: The LMA was inserted in 100% of cases and intubation was successful in 16 out of 17 cases (one failure). The propofol target concentration to obtain a RS of 3 was 1.25 +/- 0.07 microg x mL(-1). Amnesia occurred as soon as the target concentration of propofol exceeded 1 microg x mL(-1). The patients found the technique very satisfactory (median satisfaction score = 9.4/10). Incidents of coughing or nausea were observed in 47% and 5% of cases respectively. There was no oesophageal intubation and no desaturation (SpO2 < 95%).

Conclusion: Propofol administered by TCI to achieve a RS of 3 allows conscious intubation to be performed through a LMA under satisfactory conditions. A LMA could be a possible alternative to a "conscious" fibroscopy.