technical performance and side effects of remifentanil as patient-maintained tci in comparison with morphin bolus pca after major abdominal surgery

U Mohl, C Zimmermann, M Zammert, J Flaschar, S Schraag

Department of Anaesthesiology, University of Ulm, D-89075 Ulm, Germany

Background and Goal of study: Remifentanil (REMI) is increasingly used as the analgesic component during general anaesthesia. However, the appropriate transition to post-operative analgesia remains a challenge. The use of a manual controlled REMI infusion has been associated with a high incidence of respiratory side effects and periods of inadequate analgesia (1)(2). We tested the technical performance and safety of a patient-maintained Remifentanil target-controlled infusion (TCI) against standard Morphine PCA.

Materials and Methods After obtained institutional ethic`s committee approval and written informed consent, 62 male premedicated patients undergoing elective radical prostatectomy in Propofol-Remifentanil anaesthesia were studied. They were allocated randomly in three groups to receive postoperative Remifentanil TCI-PCA (Group 1), Morphine PCA, with additional priming of either a low-dose bolus (0.1 mg kg^-1, Group 2), or a high-dose bolus (0.25 mg kg^-1, Group 3) 15min prior to end of surgery. Study design was double-blind and double-dummy. During the 24 hour observation period any episode of patient- or technology-related side effects and problems were noted. Statistical analysis was provided by the nonparametric Kruskal-Wallis test with a significance level of a=0.05.

Results and Discussion: Incidence of side effects across 24 hours treatment related to either drug effect in patients or technology are listed in the table below (values given in %, CP=cardiopulmonary):

GROUP	REMI PCA-TCI (n=23)	MO PCA low (n=20)	MO PCA high (n=19)	p-value
Patient:
Nausea	30.4	10.0	26.3	0.025
Vomiting	8.7	5.0	5.2	0.42
Shivering	26.0	25.0	5.2	0.17
CP Side effects	13.1	5.0	0	0.22
Rescue analgesia	8.7	0	0	n.d.
Technology:
No consequence	4.3	5.0	5.2	0.98
With consequence	21.7	0	0	n.d.

Only one patient both in the REMI and MO low group had a respiration rate < 10 min^–1 over 5 minutes and two patients in the REMI group developed bradycardia with a HR < 45 bpm.

Conclusion: Patient-maintained REMI TCI appears to be a safe alternative when compared to standard MO PCA. Besides a higher incidence in shivering, the drug related side effects are comparable between both techniques. However, a significant amount of technical problems which interfered with the delivery of analgesia requires further refinement of the REMI prototype system and the observation of the patients in a high dependency environment.

References:

[1] Schüttler J et al. Anaesthesia 1997; 52:307-17.

[2} Bowdle TA et al Anesth Analg 1996; 83:1292-7.