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Post anaesthetic myopathy/neuropathy in horses undergoing magnetic resonance imaging compared to horses undergoing
P Franci1, E A Leece, J C Brearley
1Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk, CB8 7UU, UK.
Reasons For Performing Study:
Patient positioning and long anaesthetic duration required for magnetic resonance imaging (MRI) may result in a higher frequency of post anaesthetic myopathy/neuropathy syndrome (PAMNS) as compared to horses undergoing anaesthesia for surgery.
Hypothesis:
Equine anaesthesia for MRI is associated with a higher frequency of PAMNS than anaesthesia for nonemergency, nonabdominal surgery.
Methods:
Anaesthetic and medical records of horses (n = 633) undergoing MRI or surgery between January 2001 and January 2005 (inclusive), were reviewed. Information obtained included patient details (breed, sex, age, bodyweight), area of body scanned or involved in surgery, body position, anaesthetic and inotropic agents administered, anaesthetic duration, adverse events during anaesthesia and outcome at 7 days. Data were examined by cross tabulation and Chi-square or Fisher's exact test of association. The influence of individual variables was examined by univariant and multivariant analysis models.
Results:
There were no statistically significant differences between the 2 groups in parameters examined, except that horses in the MRI group were heavier (P<0.0001) and anaesthetic duration longer in the surgery group (P<0.004). Eight horses (2.3%, 95% Confidence interval [CI]: 1.1-4.2) in the MRI group had clinical signs of PAMNS in the post anaesthetic period, whereas only 2 horses (0.98%, 95% CI: 0.2-2.8) in the surgery group were affected. This was not statistically significantly different (odds ratio = 2.7, 95% CI: 0.8-13, P = 0.3). Two horses undergoing MRI were subjected to euthanasia due to the severity of PAMNS.
Conclusions:
There was no difference in the occurrence of PAMNS between the 2 groups.
Potential Relevance:
The risk of performing general anaesthesia for diagnostic procedures such as MRI may not be greater than that for a surgical procedure. However, the benefits should be carefully weighed against the risks involved.
Insights
Magnetic resonance imaging (MRI) in horses does not increase the risk of post-anesthetic myopathy/neuropathy syndrome (PAMNS) compared to surgery. Careful consideration of benefits versus risks is still advised for equine anesthesia.
Area of Science:
- Veterinary Anesthesiology
- Equine Medicine
- Neuromuscular Disorders
Background:
- Patient positioning and prolonged anesthesia for equine magnetic resonance imaging (MRI) may increase the risk of post-anesthetic myopathy/neuropathy syndrome (PAMNS).
- This study investigates the frequency of PAMNS in horses undergoing MRI versus those undergoing surgery.
Purpose of the Study:
- To compare the incidence of PAMNS in horses undergoing anesthesia for MRI versus anesthesia for nonemergency, nonabdominal surgery.
- To determine if equine anesthesia for diagnostic MRI poses a higher risk of PAMNS than anesthesia for surgical procedures.
Main Methods:
- Retrospective review of anesthetic and medical records for 633 horses from January 2001 to January 2005.
- Data collected included patient demographics, procedure details (MRI vs. surgery), anesthetic agents, duration, and adverse events.
- Statistical analysis involved cross-tabulation, Chi-square/Fisher's exact tests, and univariant/multivariant models to assess associations.
Main Results:
- No statistically significant differences in PAMNS occurrence between the MRI and surgery groups (2.3% vs. 0.98%).
- Horses in the MRI group were heavier, and anesthetic duration was longer in the surgery group.
- Two horses undergoing MRI required euthanasia due to severe PAMNS, highlighting potential risks despite overall similar incidence.
Conclusions:
- The incidence of PAMNS in horses undergoing anesthesia for MRI is not significantly different from that for surgical procedures.
- General anesthesia for diagnostic procedures like MRI may not carry a greater risk than for surgery.
- The benefits of diagnostic procedures should be carefully weighed against potential anesthetic risks.
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