Target-controlled infusion (TCI) for fiberoptic intubation

E. Knolle. Dept.(B) of Anaesthesiology & General Intensive Care, University of Vienna, A-1090 Vienna, Austria

Background & Goal

For fiberoptic intubation it is mostly recommended to keep the patient awake because the spontaneous breathing can be maintained and sufficient oxygenation is guaranteed (1). Nevertheless the procedure may be extremely unpleasant for the patient. The target-controlled infusion (TCI) of propofol can be used for sedation during oral surgery because the infusion rate can be adapted very quickly to keep up a sufficient spontaneous breathing and the ability to cough (2). It might be also possible to use this technique for sedation during fiberoptic intubation without giving up the advantages of awake fiberoptic intubation. We report our experiences with 10 patients (ASA I-II, no premedication) who were intubated with fiberoptic endoscopy for general anaesthesia necessary for ambulatory oral surgery procedures.

Materials & Methods

The patients were monitored by electrocardiogram, automatic blood pressure, pulse oximetry and frequency of respiration. Oxygen was supplied to the patient’s nose (3l×min^-1). After intravenous application of atropine (3µg×kg^-1) propofol was administered by TCI (Diprifusor^R, Zeneca, UK) (3), adjusting at first a target concentration of 2.5µg×ml^-1. We regarded the sedation to be sufficient, when the patient did not react to questions, oxygenation did not fall and spontaneous breathing was kept regularly. If necessary the target concentration was adapted in steps of 0.2µg×ml^-1. When a stable sedation was reached the patient received a bolus of Alfentanil (10µg×kg^-1) and the nasotracheal fiberoptic intubation was performed.

Results

No patient had noticed the intubation. The respiratory rate did not fall below 10×min^-1 and peripheral oxygenation was always above 95%. Blood pressure and heart rate did not change > 30% and we did not observe any pharyngeal reflexes. Laryngeal movements were rarely so that the position of the laryngeal aperture was easy to find by the fiberoptic endoscope. In each case the tracheal intubation was successful with the first trial. Nevertheless the time for reaching the appropriate sedation level to start the intubation was at least 15 minutes.

Conclusion

Using a propofol TCI-system nasotracheal fiberoptic intubation can be performed under continuous sedation without reducing the patient safety.

References

1. Anesthesiology (1991)75: 1087-1110.

2. Br Dent J (1997)183: 204-208.

3. Eur J Anaesthesiol Suppl.(1997)15: 29-31