Anestesia intravenosa total com propofol e cetamina em ovino pré-medicado com cetamina, midazolam e tramadol - relato de caso

Abstract

The total intravenous anesthesia (TIVA) is a commonly used technique in humans and has been instituted in anesthesia of small animals. The use of this technique only became popular in the last decade, due to lack of drugs with suitable pharmacokinetic profiles, because the drugs available so far, had a cumulative effect, causing prolonged recovery from anesthesia. The objective was to test the infusion of ketamine and propofol in laparotomy sheep premedicated with ketamine, midazolam and tramadol. Premedication consisted of ketamine 4.5 mg kg-1, midazolam 0.1 mg kg-1 and tramadol 2 mg kg-1, induction with propofol 3.5 mg kg-1 combined with 1 mg kg -1 ketamine and maintained with propofol + ketamine at doses of 0.28 mg kg-1min-1 and 0.06 mg kg-1min-1, respectively for 60 minutes. Besides the evaluation of cardiorespiratory effects (heart rate - HR, and breathing - ƒ, oxygen saturation, oxyhemoglobin – O2 saturation, mean arterial pressure - MAP, final volume of expired carbon dioxide - ETCO2, volume of inspired oxygen - O2 insp), of rectal temperature (T), changes blood gas, blood count and liver function (aspartate transaminase - AST and alkaline phosphatase - ALP) and renal (creatinine), assessed the quality of anesthesia, muscle relaxation and anesthesia. After induction of anesthesia administered, every 10 minutes the parameters noted above. The blood gas samples were collected at T0, T30 and T60. In T60 venous blood was collected for counts and serum chemistry and comparison with the pre-surgical examinations. Held regional epidural blockade with a combination of lidocaine and bupivacaine, both with epinephrine and a dose of 0.13 mg kg-1, and 0.1 mg kg-1 morphine. Hypoproteinemia and anemia occurred compared to the T60 and the presurgical examinations. All cardiorespiratory parameters evaluated were limited to saline for the species, with only the ETCO2 less than desired. HCO3 - increased at T0, T30 and T60 in relation to the physiological, metabolic alkalosis occurred, while K+ decreased at T30 and T60, falling below the desired. We conclude that TIVA protocol tested in sheep maintained cardiovascular stability and satisfactory surgical anesthesia to perform the laparotomy flank and the association with epidural anesthetic was crucial in maintaining adequate anesthesia and analgesia of patients undergoing this surgical procedur, and maintaining the gavage have contributed noticeably to avoid bloating during surgery.