Comparison of two anesthetic protocols for feline blood donation

Abstract

ObjectiveTo compare hemodynamic variables during, and recovery quality following, anesthesia for feline blood donation using intramuscular ketamine–midazolam–butorphanol (KMB) versus inhaled sevoflurane in oxygen (SEV). Study designProspective blinded, randomized, crossover study. AnimalsTwenty healthy, client-owned, mixed breed cats, aged 4–8 years, weighing 5.2–6.4 kg. MethodsCats were anesthetized with KMB for one donation and SEV for another. Heart rate (HR), respiratory rate (fR), pulse quality, mucous membrane color, capillary refill time, arterial hemoglobin saturation with oxygen (SpO2), and noninvasive arterial blood pressure (Doppler) were assessed by a blinded observer every 1 minute during collection. A nonblinded anesthesiologist delivered drugs and responded to hemodynamic changes. Each donation consisted of 55 mL of whole blood drawn via jugular puncture over 5–22 minutes. Donors received 60 mL subcutaneous lactated Ringer's solution before recovery. Donors were monitored for a minimum of 4 hours post-donation, before returning home. Owners, unaware of anesthetic protocol, completed a questionnaire regarding their cat's behavior during the 24 hours following donation. ResultsBoth protocols provided adequate restraint but were complicated by significant hypotension, requiring intervention in 16 (84%) SEV cats, and eight (42%) KMB cats. KMB cats experienced post-procedure hyperthermia, with body temperatures >103.5°F. All animals responded to symptomatic therapy within 2 hours. Owners noted a significantly faster return to normal behavior at home following SEV. ConclusionAll cats experienced hypotension, with many animals requiring intervention. There was no significant difference between protocols in incidence and severity of hypotension. The primary post-procedure complication was hyperthermia with KMB. Clinical relevanceAs a result of the potential for hypotension during blood donation, intravenous (IV) access and blood pressure monitoring are recommended for all anesthetized donor cats, regardless of the anesthetic protocol. Post-procedure hyperthermia is a risk with KMB, so temperature monitoring is recommended. Return to normal behavior is faster with SEV.