Remifentanil for oocyte retrieval: A new single-agent monitored anaesthesia care technique

Introduction: Transvaginal puncture for oocyte retrieval is a short-lasting but painful procedure. We hypothesized that a sole infusion of the ultra-s hort acting mu-agonist remifentanil may be a suitable and well-controllable single-agent analgesic technique that can dose-dependently be applied to s pontaneously breathing patients. Methods: Fifty consenting adult women were enrolled in this prospective trial. A sedative premedication was omitted, all patients received 3 L/min of inhaled oxygen, and a sole remifentanil in fusion was started with 0.25 mu g/kg/min. Remifentanil was adjusted as need ed for pain relief (in steps of 0.05 mu g/kg/min) and finished after the la st puncture. Dosage requirements, vita I functions, oxygen saturation (as a chieved by pulse oximetry, psO(2)), adverse drug effects and the level of s edation (LOS 1-5; 1 = asleep/unarousable, 4 = calm/awake) were recorded. Re mifentanil plasma concentrations were achieved by STANPUMP pharmacokinetic simulation. Data are presented as mean+/-SD. Results: A total of 50 women (31.8+/-5.1 yr, 67.3+/-14.3 kg, ASA I or II)we re investigated. Follicular aspiration lasted 10.8+/-5.2 min, and remifenta nil was infused for 19.7+/-8.3 min. Dosage requirements were 0.25 mu g/kg/m in in 70% of all patients, 0.3 mu g/kg/min in 22%, 0.2 mu g/kg/min in 6%, a nd 0.4 mu g/kg/min in 2% of all cases. Vital signs (baseline, after 1(st) p uncture, end of surgery) nearly remained unchanged: heart frequency = 85+/- 15, 87+/-17, 90+/-17 bpm, systolic blood pressure=129+/-12,132+/-13, 131+/- 14 mmHg; respiratory rate=15+/-3, 16+/-4, 15+/-4 breaths/min; psO(2)=99+/-1 , 99+/-1, 99+/-2%. LOS was 4.0 (all), 3.9+/-0.3, 3.9+/-0.3. Remifentanil pl asma concentrations were 5.0+/-1.3 ng/ml at the start, 6.6+/-1.3 at the end of surgery and 1.2+/-0.5 at PACU arrival. Adverse drug effects:54% itching , no muscle rigidity. 94% of all women would choose this technique again. Conclusions:The sole infusion of remifentanil is a suitable and satisfying single-agent monitored anaesthesia care technique for oocyte retrieval. How ever, close anaesthetic observation - especially of the respiratory functio n - is mandatory.