O. Levionnois - Academia.edu (original) (raw)

Papers by O. Levionnois

Schweizer Archiv fur Tierheilkunde, 2011

A goat was scheduled for experimental surgery under general anesthesia. The fi rst attempt of per... more A goat was scheduled for experimental surgery under general anesthesia. The fi rst attempt of performing endotracheal intubation failed and provoked laryngeal spasm. After repeated succesful intubation of inhalation anesthesia was delivered in high concentrations of sevofl urane. Suddenly hypertension and tachycardia were observed, followed by foamy airway secretion and then severe airway hemorrhage. The authors hypothesize that laryngeal spasm provoked respiratory distress and pulmonary edema. The delivered high concentrations of sevofl urane probably enhanced a hyperadrenergic response, predisposing to the development of airway hemorrhage.

Veterinary Anaesthesia and Analgesia, 2011

Objective To evaluate the peri-operative analgesic efficacy of intra-articular bupivacaine admini... more Objective To evaluate the peri-operative analgesic efficacy of intra-articular bupivacaine administered before or after stifle arthrotomy.

Toxicology and Applied Pharmacology, 2006

Ketamine is widely used as an anesthetic in a variety of drug combinations in human and veterinar... more Ketamine is widely used as an anesthetic in a variety of drug combinations in human and veterinary medicine. Recently, it gained new interest for use in long-term pain therapy administered in subanesthetic doses in humans and animals. The purpose of this study was to develop a physiologically based pharmacokinetic (PBPk) model for ketamine in ponies and to investigate the effect of lowdose ketamine infusion on the amplitude and the duration of the nociceptive withdrawal reflex (NWR).

Schweizer Archiv für Tierheilkunde, 2014

A survey was performed to evaluate the use of perioperative analgesia in dogs and cats by veterin... more A survey was performed to evaluate the use of perioperative analgesia in dogs and cats by veterinary practitioners. Questions were grouped in seven sections recording personal data, education in veterinary analgesia, general ideology regarding treatment of perioperative pain, personal experience, assessment, and use of main analgesics to treat perioperative pain. A total of 258 received forms were analyzed. Based on 5 questions, 88 % showed excellent motivation to use perioperative pain therapy. The main reason declared for the use of analgesics was to relieve the patient from pain (64.1 %). Most veterinarians reported to routinely administer analgesics before (71 -96 %) or after (2 -23 %) surgery. The most used analgesics were non-steroidal anti-infl ammatory drugs (carprofen, meloxicam) and opioids (butorphanol, buprenorphine). Animals were routinely evaluated for pain after recovery. Only 43.8 % of veterinarians declared to use loco-regional anaesthesia. Swiss veterinarians appear to recognize well the need for perioperative pain treatment. However, weakness was shown in evaluating pain severity, distinguishing between opioid classes, and using loco-regional anaesthesia.

Laboratory Animals, 2005

A sheep was anaesthetized for implantation of a novel device (MitroFast s ) to replace the poster... more A sheep was anaesthetized for implantation of a novel device (MitroFast s ) to replace the posterior leaflet of the mitral valve. Anaesthetic management included a balanced anaesthetic protocol and consisted of propofol or isoflurane combined with fentanyl infusion (0.15-0.4 mg/kg/min). Deliberate hypothermia during cardiopulmonary bypass was set at 34.5-35.51C. Surgery proceeded uneventfully. Total time of aortic cross-clamping was 35 min and total time on extracorporeal circulation was 60 min. Visual inspection, intracardiac pressure testing and transesophageal echocardiography indicated proper functioning of the device. The anaesthetic period was uneventful, but recovery was prolonged with central nervous and respiratory depression and marked hypoxaemia. Administration of naloxone (1.5 mg/kg, repeated twice at 15-20 min intervals) reversed the central nervous and attenuated the respiratory depressions. An initially low rate of urine production normalized after rewarming and a single intravenous administration of furosemide.

Laboratory Animals, 2008

A one-year-old healthy sheep received an implant stenting the mural ('posterior') leaflet of the ... more A one-year-old healthy sheep received an implant stenting the mural ('posterior') leaflet of the mitral valve. The experiment was authorized by the Cantonal Ethical Committee. The surgery was performed on the open, beating heart during cardiopulmonary bypass (CPB). Management of anaesthesia was based on isoflurane with mechanical intermittent positive pressure ventilation (IPPV) of the lungs, combined with intercostal nerve blocks and intravenous fentanyl and lidocaine. Marked cardiovascular depression occurred towards the end of CPB time and required high doses of dopamine, dobutamine, lidocaine and ephedrine to allow for weaning off the CPB pump. Moreover, severe pulmonary dysfunction developed when IPPV was re-initiated after CPB. Hypoxaemia persisted throughout the recovery from general anaesthesia. Multiple organ failure developed gradually during the three postoperative days, leading to euthanasia of the animal. As described in this case, marked lung injury associated with some degree of failure of other vital organs may occur in sheep after CPB. Intraoperative cardiorespiratory complications when weaning-off may indicate the development of 'post-pump syndrome'.

American Journal of Veterinary Research, 2009

Objective-To evaluate pharmacokinetics of ketamine and norketamine enantiomers after constant rat... more Objective-To evaluate pharmacokinetics of ketamine and norketamine enantiomers after constant rate infusion (CRI) of a subanesthetic dose of racemic ketamine or S-ketamine in ponies. Animals-Five 6-year-old Shetland pony geldings that weighed between 101 and 152 kg. Procedures-In a crossover study, each pony received a CRI of racemic ketamine (loading dose, 0.6 mg/kg; CRI, 0.02 mg/kg/min) and S-ketamine (loading dose, 0.3 mg/kg; CRI, 0.01 mg/kg/min), with a 1-month interval between treatments. Arterial blood samples were collected before and at 5, 15, 30, 45, and 60 minutes during drug administration and at 5, 10, 30, and 60 minutes after discontinuing the CRI. Plasma ketamine and norketamine enantiomers were quantified by use of capillary electrophoresis. Individual R-ketamine and S-ketamine concentration-versus-time curves were analyzed by use of a monocompartmental model. Plasma disposition curves for R-norketamine and S-norketamine were described by estimating the area under the concentration-versus-time curve (AUC), maximum concentration (Cmax), and time until Cmax. Results-Plasma concentrations of S-ketamine decreased and biodegradation products increased more rapidly after S-ketamine CRI, compared with results after racemic ketamine CRI. The R-norketamine was eliminated faster than was the S-norketamine. Significant differences between treatments were found for the AUC of S-ketamine and within the racemic ketamine CRI for the AUC and Cmax of norketamine isomers. Conclusions and Clinical Relevance-CRI of S-ketamine may be preferable over CRI of racemic ketamine in standing equids because the S-enantiomer was eliminated faster when infused alone instead of as part of a racemic mixture. (Am J Vet Res 2009;70:831-839) amounts of 2 optical isomers (ie, the R-ketamine and S-ketamine enantiomers). Although the R-enantiomer and S-enantiomer of ketamine have the same chemical formula, their atoms occupy different positions in space, which leads to different spatial relationships in