Complications associated with anaesthesia for ocular surgery: a retrospective study 1989-1996.

The research paper discusses a study conducted to understand the complications associated with anaesthesia during ocular surgery for horses. The study showed that a significant number of horses moved during surgery, which can be mitigated by using an anaesthetic gas analyser for monitoring.

Retrospective Study to Identify Anaesthesia Complications

• The research involved a retrospective examination of the medical records of horses who had been anaesthetised for different surgical procedures. 74 records were of horses anaesthetised for eye enucleation, 65 for surgery of the eye and adnexa, and 51 for splint bone excision.
• The aim of the study was to understand any complications that might have arisen due to the anaesthesia during the surgery.

Findings from the Study

• Observations revealed that 53% of horses undergoing eye enucleation showed movement during surgery, significantly more than the other groups. This suggests a possible relationship between the type of surgery and the patients’ response to anaesthesia.
• The use of an anaesthetic gas analyser was found to be effective in reducing the incidence of movement, suggesting that it may help in ensuring better control and monitoring of anaesthesia.
• Transient hypertension occurred in 6 horses during the removal of the eye, indicating a possible cardiovascular impact due to the surgery or anaesthesia. Additionally, one horse showed a brief decrease in heart rate at the start of surgery to remove a mass on the third eyelid.
• The research team also noted an increased incidence of unsatisfactory recovery from anaesthesia, marked by multiple attempts to stand, after ocular surgery compared with splint bone excision.

Conclusions from the Study

• Based on the findings, the researchers concluded that the oculocardiac reflex, a decrease in pulse rate associated with traction on the eye muscles, was not active in these horses during ocular surgery. This negates the possibility of the reflex being responsible for any adverse reactions to the surgery or anaesthesia.
• It was also established that greater attention is needed in providing adequate analgesia and depth of anaesthesia, which the use of an anaesthetic gas analyser could facilitate. This could potentially improve the control and monitoring of anaesthesia, avoiding incidents of movement during surgery.
• Lastly, the study concluded that horses have a greater risk of unsatisfactory recoveries from anaesthesia following ocular surgery compared with other types of surgery. This highlights the need for more specialised post-surgery care for such cases.