Comparison Of Propofol/Remifentanil Sedation For Colonoscopy Using Either Effect-Site TCI Or Manual Control.

Traore B, Engelman E, Baurain M, Barvais L.

Department of Anaesthesia, Erasme Hospital, Free University of Brussels, Belgium

Introduction

Recently a TCI system allowing the combined control of the calculated concentrations of propofol and remifentanil at their theoretical site of action (Ce) has become available (Base Primea, Fresenius, Brezins, France).  The aim of the study was to evaluate if there was any benefit to use an effect-site TCI propofol/remifentanil sedation technique compared to a manual propofol/remifentanil infusion technique for a colonoscopy procedure.

Material and Method

After ethical committee approval and written informed consent, forty-two ASA physical status 1 and 2 patients were randomised in two groups, prospectively. All patients received 0.5 mg oral alprazolam as premedication. SPO2 and respiratory rate were continuously recorded. Systolic blood pressure and heart rate were monitored every 3 minutes. In both groups, a one-way valve was placed on the IV line and O2 40% by face mask was given during the whole procedure.  In the manual group (M), anaesthesia was induced with a propofol bolus (1 mg/kg) followed by a continuous propofol infusion of 10 mg/kg/hour and a remifentanil infusion of 0.05 µg/kg/min.  In the effect-site TCI group (E), propofol was started at 2 µg/ml Ce (1) and remifentanil at 1 ng/ml Ce (2). The flow rates and Ce of propofol were progressively increased until LOC was obtained in group M and E, respectively. Thereafter, propofol and remifentanil flow rates and Ce were adapted according to the haemodynamic and respiratory parameters. Any episode of systolic blood pressure below 90 mmHg was treated by ephedrine.  Any respiratory rate below 8/min or any episode of SPO2 less than 93 were treated.  The number of interventions on each infusion pump, the total doses of propofol and remifentanil, the time duration to induce the patient and to awake the patient were noticed by an independent clinical data manager. The same two senior anaesthetists participated to the protocol.

Results

Both groups patients were comparable with respect to demographic data and duration of colonoscopy.  No statistical difference was evidenced between both groups, except for the total mean dose of remifentanil (Group E>M).  The anaesthetist’s preference was largely in favour of the effect-site TCI control because of the more logical theoretical pharmacokinetic approach, the automatic adaptation of the drug delivery according to age and BMI and the easy to use interface of the Base Primea system from Fresenius.                                                     

Remi : Mean dose of Remifentanil  ;  Prop : Mean dose of Propofol

N Modif. : Number of modifications of Propofol and Remifentanil Ce or infusion rates in groups E and M, respectively

N Events: Number of episodes of hypotension, hypertension, bradycardia, tachycardia, desaturation, controlled ventilation, ephedrine

Discussion

Combined administration of remifentanil and propofol for colonoscopy has been demonstrated to provide sufficient analgesia, satisfactory hemodynamic stability, minor respiratory depression, and rapid recovery (3).  Our hypothesis was to test if the anaesthetist will modify less often the target Ce of both drugs in group E than the pump infusion rates in group M to get the same haemodynamic and respiratory stability.  Our results showed that the haemodynamic events and respiratory side effects were rare in both groups M and E and there was no statistical difference between both groups, except the difference of the remifentanil dose which could partially be explained by the anaesthetist’s confidence in the control of the effect-site TCI system for remifentanil. 

In conclusion, the combination of propofol and remifentanil administered by continuous infusion titrated either manually or using an effect-site TCI system is a very good sedation technique for colonoscopy.  The effect-site. propofol and remifentanil TCI seems to be preferred by a well trained anaesthetist thanks to the pharmacokinetic understanding of the drug titration and the friendly and easy to use interface of the Base Primea.

References

1.             Schnider et al, Anesthesiology 1999; 90: 1502-16     

2.             Minto et al, Anesthesiology 1997; 86: 10-23

3.             Rudner R et al, Gastrointest Endosc. 2003 May; 57(6): 657-63.