Sacrococcygeal block for catheterising the blocked cat
8-year-old blocked male cat, hypothermic and mildly hypotensive, improved with fluids. Hyperkalaemia is controlled and he must be catheterised with the lightest possible anaesthetic load.
Which option is most appropriate to facilitate catheterisation?
chevron_right Show answer and explanation
A. Acepromazine to relax the urethra before catheterisation
Acepromazine causes vasodilation and hypotension, undesirable in a cat just recovering from hypotension, and its effect is long-lasting and not reversible.
B. Sacrococcygeal block with lidocaine together with light opioid-based sedation
Correct. The block desensitises the penis, perineum and urethra and relaxes the urethral muscles, so much less sedation is needed. It is a simple technique with few cardiovascular effects.
C. High-dose ketamine as the sole agent, because it maintains blood pressure
In cats ketamine is largely eliminated by the kidney; with azotaemia its effect is prolonged. At high doses and alone it causes muscle rigidity and rough recoveries.
D. Mask induction with isoflurane without premedication
Mask induction is stressful, requires high anaesthetic concentrations that cause hypotension, and increases the risk of aspiration without airway control.
lightbulb Key takeaway
In the blocked cat, a sacrococcygeal block is a cheap and safe way to reduce the sedation needed. Stabilise first (potassium, volume, temperature) and choose short-acting, reversible drugs.
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.