Data presented at RCOG 2024 reflect the suitability of methoxyflurane ? a short-acting analgesic delivered via a handheld, self-administered inhaler device ? for use in the performance of minor gynaecology procedures.

“Methoxyflurane [is a] cheap, easy-to-use [analgesic] to reduce general anaesthetic need,” noted first author Dr Lauren Croft from the Leeds Teaching Hospitals National Health Service Trust, Obstetrics & Gynaecology, Leeds,UK, at RCOG 2024.

Over 6 months, methoxyflurane was offered to women presenting at the Gynaecology Acute Treatment Unit Leeds for manual vacuum aspiration (MVA) due to retained products of conception following a miscarriage. After the procedure, participants were asked to rate their pain score on a scale of 0?10 (0=no pain, 10=worst ever pain). [https://www.disabled-world.com/health/pain/scale.php, accessed November 26, 2024]

Most of the participants who underwent an MVA did so using methoxyflurane and a local anaesthetic via a paracervical block. Women were excluded if methoxyflurane was contraindicated; general anaesthetic, or nitrous oxide with oxygen, was used instead. [RCOG 2024, abstract MTeP-02]

Prior to the introduction of methoxyflurane, 30 women have undergone MVA with either a local anaesthetic or nitrous oxide with oxygen. Of these, a majority (87 percent) reported a pain score of 6?10. The remaining 13 percent reported a pain score of 0?5. The mean pain score was 7.2.

During the 6-month period, methoxyflurane was used 74 times ? 53 for MVA and 21 for other minor gynaecology procedures. Seven women did not provide a pain score, while two were unable to tolerate methoxyflurane. The mean pain score during this period was 4.2.

Of the remaining 44 women who had MVA, only 30 percent reported a pain score of 6?10. Seventy percent had a pain score of 0?5, with the mean pain score being 3.9. One MVA had to be abandoned.

Allows same-day procedures

Common gynaecological procedures such as MVA can be done in both inpatient and outpatient settings, but the latter may require a general anaesthetic, Croft noted, as “the procedures may not be well tolerated due to lack of analgesia.”

“[Methoxyflurane] can be used alone or in combination with a local anaesthetic, allowing same-day procedures to be performed without the risks of general anaesthesia and the need for an operating theatre team,” she said.

“This audit [aimed] to address whether methoxyflurane is well tolerated and provides adequate analgesia for women undergoing outpatient gynaecology procedures, particularly MVA … [It] shows that methoxyflurane is a well-tolerated inhaled analgesic suitable for use in minor gynaecology procedures,” she continued.

Moreover, methoxyflurane is a quick and effective alternative for use in an outpatient setting, which could obviate the need for pricey general anaesthetics and extended hospitalizations and provide pain relief superior to that achieved from a local anaesthetic or nitrous oxide with oxygen alone, added Croft.

She called for more investigation to ascertain the benefits of methoxyflurane without the aid of a local anaesthetic and establish its role in ambulatory gynaecology.