Anaesthesia recovery quality after racemic ketamine or S-ketamine administration to male cats undergoing neutering surgery.

Postoperative anaesthesia recovery and analgesia qualities were compared in cats anaesthetised with racemic ketamine (RS-ket) or S-ketamine (S-ket) undergoing orchiectomy. Twenty client-owned male cats received medetomidine (0.03 mg/kg) and S-ket (6 mg/kg; n = 10) or RS-ket (10 mg/kg; n = 10), all intramuscularly. After routine orchiectomy, animals received atipamezole (0.15 mg/kg) intramuscularly. Thirty and 60 min after atipamezole administration, one observer unaware of the treatment identity evaluated analgesia using a visual analogue scale (VAS) and, by means of four points scales, sedation, unprovoked behaviour and behavioural reactions to external stimuli. Cats with a VAS > or = 15 mm were to receive butorphanol. Times to sternal and standing positions were recorded. After 60 min, cats were given carprofen (4 mg/kg) subcutaneously. Anaesthesia with S-ket, at 60% of the RS-ket dose, provided faster recoveries. At 60 min, undisturbed cats in S-ket group had a trend towards fewer behavioural changes. Cats in RS-ket group were more sedate at 30 min and responded with a lower intensity to external stimulation. Immediate postoperative analgesia was considered adequate for both groups and no cat required butorphanol administration.

Influence of pre-anaesthetic thoracic radiographs on ASA physical status classification and anaesthetic protocols in traumatized dogs and cats.

The purpose of this study was to evaluate if pre-anaesthetic thoracic radiographs contribute to the anaesthetic management of trauma patients by comparing American Society of Anesthesiologists Physical Status Classification (ASA grade) with and without information from thoracic radiography findings. Case records of 157 dogs and cats being anaesthetized with or without post-traumatic, pre-anaesthetic chest radiographs were retrospectively evaluated for clinical parameters, radiographic abnormalities and anaesthetic protocol. Animals were retrospectively assigned an ASA grade. ASA grades, clinical signs of respiratory abnormalities and anaesthesia protocols were compared between animals with and without chest radiographs. The group of animals without pre-anaesthetic radiographs was anaesthetized earlier after trauma and showed less respiratory abnormalities at presentation. The retrospectively evaluated ASA grade significantly increased with the information from thoracic radiography. Animals with a higher ASA grade were less frequently mechanically ventilated. Pre-anaesthetic radiographs may provide important information to assess the ASA grade in traumatized patients and may therefore influence the anesthesia protocol.

Balanced anesthesia and ventilation strategies for an alpaca (Lama pacos) with an increased anesthetic-risk.

We report the use of a balanced anesthetic technique in a three-year-old, female Huacaya alpaca with an increased anesthetic risk that underwent an extensive dental surgery. Anesthesia was provided with an infusion of midazolam, fentanyl, S-ketamine and low concentrations of isoflurane in oxygen. The mandibular alveolar nerve was desensitized with a lidocaine-bupivacaine combination. The alpaca showed signs of hypoxemia fifteen minutes after anesthesia induction and arterial blood gases confirmed severe venous admixture. Application of positive end expiratory pressure (PEEP) of 6-9 cm H2O improved the arterial oxygenation. Other cardiopulmonary variables remained within the normal range. At the end of surgery, sarmazenil was administered to antagonize the effects of midazolam and emergence from anesthesia was smooth and uneventful. Flunixine meglumine and a transdermal delivery system for fentanyl were administered for post-operative analgesia. This method of balanced anesthesia allowed for an adequate anesthetic plane and a safe recovery, however, special ventilation strategies (PEEP) had to be applied.

Stereoselective pharmacokinetics of ketamine and norketamine after racemic ketamine or S-ketamine administration during isoflurane anaesthesia in Shetland ponies.

BACKGROUND: The arterial pharmacokinetics of ketamine and norketamine enantiomers after racemic ketamine or S-ketamine i.v. administration were evaluated in seven gelding ponies in a crossover study (2-month interval). METHODS: Anaesthesia was induced with isoflurane in oxygen via a face-mask and then maintained at each pony's individual MAC. Racemic ketamine (2.2 mg kg(-1)) or S-ketamine (1.1 mg kg(-1)) was injected in the right jugular vein. Blood samples were collected from the right carotid artery before and at 1, 2, 4, 8, 16, 32, 64, and 128 min after ketamine administration. Ketamine and norketamine enantiomer plasma concentrations were determined by capillary electrophoresis. Individual R-ketamine and S-ketamine concentration vs time curves were analysed by non-linear least square regression two-compartment model analysis using PCNonlin. Plasma disposition curves for R-norketamine and S-norketamine were described by estimating AUC, C(max), and T(max). Pulse rate (PR), respiratory rate (R(f)), tidal volume (V(T)), minute volume ventilation (V(E)), end-tidal partial pressure of carbon dioxide (PE'(CO(2))), and mean arterial blood pressure (MAP) were also evaluated. RESULTS: The pharmacokinetic parameters of S- and R-ketamine administered in the racemic mixture or S-ketamine administered separately did not differ significantly. Statistically significant higher AUC and C(max) were found for S-norketamine compared with R-norketamine in the racemic group. Overall, R(f), V(E), PE'(CO(2)), and MAP were significantly higher in the racemic group, whereas PR was higher in the S-ketamine group. CONCLUSIONS: Norketamine enantiomers showed different pharmacokinetic profiles after single i.v. administration of racemic ketamine in ponies anaesthetised with isoflurane in oxygen (1 MAC). Cardiopulmonary variables require further investigation.