If you feel a pop, stop!

Dear Editor,

We anaesthetised a patient undergoing a temporal craniotomy with propofol and remifentanil TCI using a 20-G peripheral venous cannula located on the patient's forearm. Subsequently, we sited a second 16-G cannula in the left saphenous vein to use for the TCI infusions, as this would be in close proximity to the anaesthetic machine and always visible [1]. This was flushed with saline from a 20 ml syringe via the injection port. After a few millilitres had been administered, there was a tactile ‘give’ and an audible ‘pop’. When the syringe was removed, blood refluxed out of the injection port. The cannula was removed and another cannula was sited in the patient’s right leg; there were no further problems.

Upon review of the cannula, we found that the valve for the port had become dislodged distally (Figure 1). Subsequent testing revealed that anything administered through the hub of the cannula flowed out through the hub.

Two cannulas

This case highlights the importance of carefully checking cannulae used for TIVA. Both tactile and audible abnormalities highlighted the issue in this case. We recommend that both the hub and injection port are flushed before declaring a cannula safe, and a quick visual assessment is performed after each drug administration.

Mark Parson

Jamie Gibson
Anaesthetic Registrars
Royal Sussex County Hospital, Brighton

Twitter: @jamielgibson1; @biopsychosoc

References

Nimmo AF, Absalom AR, Bagshaw O, et al. Guidelines for the safe practice of total intravenous anaesthesia (TIVA). Joint Guidelines from the Association of Anaesthetists and the Society for Intravenous Anaesthesia. Anaesthesia 2019; 74: 211-24.

You might also be interested in:

Vaccine to artificial intelligence

In the rich history of medicine, various innovations have made significant differences to humanity.

Exovent: an accelerated innovation journey in 2020

2020 was an exceptional year for the Exovent team. It has been an unusual year for everyone with a global pandemic disrupting life, while putting enormous strain on the NHS.

Exovent: a new development from old technology

Few contemporary anaesthetists imagining negative pressure ventilation would picture a modern, lightweight, torso-only device, and fewer still would imagine it being described as “extremely pleasant” by a wide-awake subject who was able to eat, drink and talk freely during exhalation (

Preventing dual humidification errors in ventilation circuits

Artificial humidification systems are a vital component of ventilation circuits in order to condition cold and dry medical gases before they enter the lungs.

If you feel a pop, stop!