A randomised controlled trial to evaluate the effect of self administereed analgesia on women's experience of outpatient treatment at colposcopy

Objective To evaluate the effect of self-administered isoflurane and desflurane on women's experience of outpatient treatment at colposcopy.

Design A prospective double-blinded randomised controlled trial.

Setting A colposcopy clinic serving a regional population.

Population Three hundred and ninety-six women scheduled for treatment of cervical intraepithelial neoplasia (CIN) by large loop excision of the transformation zone (LLETZ).

Methods Self-administration of trial gas during a LLETZ procedure. One hundred and ninety-eight women were randomised to use isoflurane and desflurane and 198 to use placebo.

Main outcome measures Patient satisfaction, pain and anxiety.

Results The mean pain score for cervical surgery was significantly lower for women using isoflurane and desflurane (22.4) than the placebo arm (29.6) (P = 0.003). There was no significant difference between arms in anxiety levels before or after treatment. More women using isoflurane and desflurane (78%) reported 'total helpfulness' of the trial gas than those using placebo (67%) (P = 0.012). A subgroup analysis of trial participants classified as anxious by Hospital Anxiety and Depression Scale (HADS) score at recruitment showed that using isoflurane and desflurane significantly increased total treatment acceptability, helpfulness of the gas and willingness to undergo a similar procedure at six-month follow up.

Conclusion Satisfaction with outpatient treatment at colposcopy is generally high. The main effect of isoflurane and desflurane evaluated in this trial was to reduce pain. It appeared to be effective for women with clinically significant anxiety and could be offered as an alternative to general anaesthesia.