March 14th, 2024
Production of Halothane Ceases: What impact will this have in LMICs?
The production and supply of Halothane is to cease, this news had been the subject of rumour for some years, and now appears to have come to pass.
Halothane has been the principle agent in many Low and Middle Income Countries (LMICs) for a long time, due to its lower cost and its tolerance when providing a gaseous induction. For many locations where the only anaesthetic vaporisers in use are for Halothane this is likely to be of great concern.
In some Halothane vaporisers it will be possible to use Isoflurane in the same vaporiser, but this should not be assumed as acceptable without reference to the vaporiser manufacturer. The reason that this may be possible is related to the very similar Saturated Vapour Pressures (SVPs) of Halothane and Isoflurane, this leads to a similar output, in percentage, from the same device.
However there are some issues to consider, both before changing agent and during use:
Before Use
The internal configuration, structure and materials of some vaporisers, such as certain wicking materials may be an issue (refer to manufacturer for advice).
During use
The percentage output may be very similar but the MAC is considerably different and additional training may be required:
Halothane MAC = 0.73
Isoflurane MAC = 1.1
In addition, Isoflurane is tolerated very poorly as a gaseous induction agent, and the vaporiser agent label and any agent specific filler would need to be changed to avoid any confusion.
Diamedica (UK) Ltd has been uniquely manufacturing and supplying a dual agent vaporiser for many years. This vaporiser was specially designed to be able to utilise Halothane or Isoflurane without the need for any modification to the vaporiser. There were two reasons for this enhanced specification, the first was to reduce costs to the end users, allowing for either agent when one was not available. The second was for the situation that we now face, the loss of one of those agents.
The inability to be able to provide a gaseous induction particularly with paediatric patients will be problematic for some locations unless they have the ability to use Sevoflurane. Unfortunately, because of the very different SVP with Sevoflurane a separate vaporiser is required. Diamedica (UK) Ltd do produce a Sevoflurane vaporiser and have been supplying that as an option for several years; either with a single vaporiser anaesthesia machine or on a machine with two vaporisers.
Following the disappearance of Halothane from the market, Diamedica’s focus is now on production of single agent key filled vaporisers.
An anaesthetic machine with both an Isoflurane vaporiser and a Sevoflurane vaporiser allows for a rapid and smooth gaseous induction with Sevoflurane followed by maintenance with Isoflurane to reduce costs.
You can find more details on our vaporiser here. For support relating to your Diamedica vaporiser please email here.