Why it’s important to monitor hospital staff exposure to Penthrox®
Penthrox ® (methoxyflurane) is an anaesthetic agent that is being used more often in emergency departments, gynaecology departments, burns units and ambulances.
This is in part because it provides emergency pain relief for adult patients with trauma and associated pain, is easy to administer and leaves the body more quickly than Entonox.
In addition, methoxyflurane is much more environmentally friendly than Entonox. In fact, it has a climate change impact of 117.7 times less CO2e compared with Entonox(1), meaning it is a much better option for NHS Trusts working towards Net Zero.
How is Penthrox ® (methoxyflurane) administered?
The manufacturer recommends a maximum of 15 mL per week in 3–6 mL doses as required and that staff avoid administration on consecutive days.
The clear, volatile liquid has a characteristic fruity odour and is administered using a custom-built Penthrox® inhaler.
The patient inhales and exhales Penthrox ® through the mouthpiece to obtain analgesia. The exhaled vapour passes through the activated-carbon (AC) Chamber to adsorb any exhaled methoxyflurane.
Why do healthcare staff need to be monitored for exposure?
Even though the AC Chamber is designed to absorb exhaled methoxyflurane, there will still be some of it released to atmosphere.
Patients will find that pain relief occurs after 6–10 inhalations and that continuous inhalation of a bottle containing 3 ml provides analgesic relief for up to 25-30 minutes.
Not only does that mean that healthcare staff can be exposed to some exhaled methoxyflurane during one administration, but throughout a shift of administering the anaesthetic to multiple patients.
As there can be risks of serious side effects due to over-exposure, the manufacturer advises that exposure of healthcare professionals to methoxyflurane should be minimised.(2)
What side effects can healthcare staff experience?
Common side effects include dizziness, drowsiness, dry mouth, headache, and nausea. Other concerning symptoms include memory loss, hepatic disorders and renal failure. (3)
Elevation of liver enzymes, blood urea nitrogen and serum uric acid have been reported in exposed maternity ward staff in delivery wards when methoxyflurane was used in the past in obstetric patients at the time of labour and delivery.(3)
There have also been reports of non-serious and transient reactions such as dizziness, headache, nausea or malaise, and reports of hypersensitivity reactions to methoxyflurane or other ingredients in healthcare professionals exposed to Penthrox ®.(3)
Whilst an occupational exposure limit has not been established for methoxyflurane by NIOSH. Human clinical and toxicity data have been independently reviewed and used to derive a Maximum Exposure Limit (MEL) of 15 ppm.(4)
How we can help you monitor for exposure to Penthrox ®
We provide monitoring of Penthrox® (methoxyflurane) in a range of hospital departments in NHS Trusts and private hospitals.
Not only does this provide important data to indicate that any control measures already in place are working effectively, it also confirms that staff are not at risk from the negative effects of over-exposure.
We do this by providing personal sampling tubes that are worn by staff throughout their shift. On completion of the monitoring program, sample tubes are returned to our laboratory for analysis. A report on our findings is then supplied to the customer.
If we can help you with monitoring, please contact us on 0333 015 4345 or email info@cairntechnology.com.
References
- Martindale AE et al. Environmental impact of low-dose methoxyflurane versus nitrous oxide for analgesia: how green is the ‘green whistle’? EMJ Published Online First: 28 September 2023. doi: 10.1136/ emermed-2022-213042
- https://bnf.nice.org.uk/drugs/methoxyflurane/#prescribing-and-dispensing-information
- https://www.medicines.org.uk/emc/product/1939/smpc#gref
- https://medicaldev.com/wp-content/uploads/2023/08/SDS_0001_R9_SDS_Penthrox.pdf
