Preoperative considerations:
Blood typing +/- crossmatch before procedure
2nd catheter placement if blood products or additional fluid boluses need to be administered

Anesthetic Considerations:
Cerenia 1 mg/kg IV
Fentanyl 5 mcg/kg IV or Hydromorphone 0.05 mg/kg IV
Midazolam 0.3 mg/kg IV
Lidocaine 1 mg/kg IV
Propofol or Alfaxalone 3 mg/kg IV

Constant Rate Infusions for perioperative analgesia:
Fentanyl 3-10 mcg/kg/hr
Lidocaine 1.5 mg/kg/hr
-lidocaine is a nice consideration for this procedure since it can reduce the incidence of arrhythmias, it provides MAC reduction of the inhalant and analgesia, and it serves as a free radical scavenger. You can either give 1-2 mg/kg boluses IV every hour during surgery or give one bolus and start an infusion as described.

Fluid Therapy:
3 mls/kg/hr of a balanced crystalloid fluid including the infusions, thus a total of 66 mls/hr (fluids + infusions). This strategy should decrease the chance of volume overload in a cardiovascularly compromised patient however the patient should be watched closely for signs of pulmonary edema (cyanosis, tachypnea, cough) in the post-operative period.
VetStarch can be considered for volume expansion since this patient has a lower total protein. This would be administer in 5 ml/kg boluses. The issue with VetStarch is you can precipitate renal failure and also promote fluid overload given the patients murmur/cardiovascular status. I would rely more on vasopressor therapy for hypotension including a dopamine infusion(5-15 mcg/kg/min) to maintain adequate blood pressure.

Ventilation: Positive pressure ventilation 8-10 mls/kg at 6-8 breaths/minute. If the patient is hypotensive then considered switching to spontaneous respirations with intermittent positive pressures breaths.

Post-operative considerations:
Recheck PCV/TS and glucose within 4 hours of surgery and PT/aPTT within 24 hours of surgery.
Continue analgesia as described either as a bolus or constant rate infusions. Dopamine can also be utilized at 3-10 mcg/kg/min to avoid excessive fluid boluses. I would avoid NSAIDs in this patient post-operatively. Phenobarbitol can be administered once the patient has recovered from anesthesia and is able to take oral medications.