Total intravenous anesthesia with Ketofol in rabbits: a comparison of the effects of constant rate infusion of midazolam, fentanyl or dexmedetomidine.

BACKGROUND: When inhalant anesthetic equipment is not available or during upper airway surgery, intravenous infusion of one or more drugs are commonly used to induce and/or maintain general anesthesia. Total intravenous anesthesia (TIVA) does not require endotracheal intubation, which may be more difficult to achieve in rabbits. A range of different injectable drug combinations have been used as continuous infusion rate in animals. Recently, a combination of ketamine and propofol (ketofol) has been used for TIVA in both human patients and animals. The purpose of this prospective, blinded, randomized, crossover study was to evaluate anesthetic and cardiopulmonary effects of ketofol total intravenous anesthesia (TIVA) in combination with constant rate infusion (CRI) of midazolam, fentanyl or dexmedetomidine in eight New Zealand White rabbits. Following IV induction with ketofol and endotracheal intubation, anesthesia was maintained with ketofol infusion in combination with CRIs of midazolam (loading dose [LD]: 0.3 mg/kg; CRI: 0.3 mg/kg/hr; KPM), fentanyl (LD: 6 µg/kg; CRI: 6 µg/kg/hr; KPF) or dexmedetomidine (LD: 3 µg/kg; CRI: 3 µg/kg/hr; KPD). Rabbits in the control treatment (KPS) were administered the same volume of saline for LD and CRI. Ketofol infusion rate (initially 0.6 mg kg- 1 minute- 1 [0.3 mg kg- 1 minute- 1 of each drug]) was adjusted to suppress the pedal withdrawal reflex. Ketofol dose and physiologic variables were recorded every 5 min. RESULTS: Ketofol induction doses were 14.9 ± 1.8 (KPM), 15.0 ± 1.9 (KPF), 15.5 ± 2.4 (KPD) and 14.7 ± 3.4 (KPS) mg kg- 1 and did not differ among treatments (p > 0.05). Ketofol infusion rate decreased significantly in rabbits in treatments KPM and KPD as compared with saline. Ketofol maintenance dose in rabbits in treatments KPM (1.0 ± 0.1 mg/kg/min) and KPD (1.0 ± 0.1 mg/kg/min) was significantly lower as compared to KPS (1.3 ± 0.1 mg/kg/min) treatment (p < 0.05). Ketofol maintenance dose did not differ significantly between treatments KPF (1.1 ± 0.3 mg/kg/min) and KPS (1.3 ± 0.1 mg/kg/min). Cardiovascular variables remained at clinically acceptable values but ketofol infusion in combination with fentanyl CRI was associated with severe respiratory depression. CONCLUSIONS: At the studied doses, CRIs of midazolam and dexmedetomidine, but not fentanyl, produced ketofol-sparing effect in rabbits. Mechanical ventilation should be considered during ketofol anesthesia, particularly when fentanyl CRI is used.

Does Addition of a Longer Acting Local Anesthetic Improve Postoperative Pain After Carpal Tunnel Release? A Randomized Controlled Trial.

PURPOSE: Carpal tunnel release (CTR) is a simple and effective treatment for carpal tunnel syndrome in patients who have failed nonsurgical management. This surgery is often performed in the ambulatory clinic under local anesthesia, with lidocaine, a short-acting agent. Few studies have investigated the use of longer acting agents, such as bupivacaine, for outpatient CTR. Therefore, the aim of our study was to compare the postoperative pain experience after CTR with the use of either our standard lidocaine solution (control) or a mixture consisting of lidocaine and bupivacaine in equal amounts (intervention). METHODS: Patients undergoing CTR were randomized into control or intervention groups. Postoperative pain severity and numbness were recorded at several timepoints within the first 72 hours. The timing and quantity of postoperative analgesic use (acetaminophen and/or ibuprofen) was also documented. Both patients and assessor were blinded to allocation. RESULTS: Our study cohort included 139 patients: 67 in the control group and 72 in the intervention group. Postoperative pain scores were significantly lower in the intervention group at 6 hours (2.3 vs 3.2) and 8 hours (2.9 vs 3.9). Additionally, patients in the intervention group reported longer time to first analgesic use than those in the control group (5.2 hours vs 3.7 hours). A greater proportion of patients in the intervention group reported postoperative numbness at nearly all time points, compared to the control group. CONCLUSIONS: Our study shows that a mixture of bupivacaine and lidocaine improves early postoperative pain but causes prolonged finger numbness when compared to lidocaine alone. As both medications are effective and feasible for outpatient CTR, surgeon and patient preference should guide local anesthetic choice. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic Ib.

Influence of fentanyl, medetomidine-fentanyl or acepromazine-fentanyl premedication on oesophageal and rectal temperature in dogs under anaesthesia.

OBJECTIVE: To compare changes in oesophageal (T-Oeso) and rectal (T-Rec) temperature in dogs during general anaesthesia and premedicated with fentanyl, medetomidine-fentanyl or acepromazine-fentanyl. STUDY DESIGN: Prospective, randomized, blind clinical study. ANIMALS: A total of 120 healthy dogs, aged 2-10 years and weighing 5-20 kg. METHODS: Dogs were randomly allocated to one of three groups. Animals of F group were premedicated with fentanyl (0.01 mg kg-1), MF group with medetomidine (0.005 mg kg-1) and fentanyl (0.01 mg kg-1) and AF group with acepromazine (0.01 mg kg-1) and fentanyl (0.01 mg kg-1). Anaesthesia was induced with propofol and maintained with isoflurane in oxygen-air mixture. Fentanyl was administered continuously (0.01 mg kg-1 hour-1). The T-Oeso, T-Rec and ambient temperatures were recorded after induction (T0) and subsequently at 10 minute intervals for 60 minutes (T10-T60). Data were analysed using anova or their non-parametric equivalents (p < 0.05). RESULTS: Median T-Oeso was significantly higher in MF group between T0-T20 compared with other groups. Median T-Oeso significantly decreased in F group from 38.0 °C (T0) to 37.4 °C (T30), 37.1 °C (T40), 36.9 °C (T50) and 36.6 °C (T60), in MF group from 38.3 °C (T0) to 37.7 °C (T30), 37.5 °C (T40), 37.2 °C (T50) and 37.1 °C (T60) and in AF group from 37.7 °C (T0) to 37.3 °C (T40), 37.2 °C (T50) and 37.1 °C (T60). The T-Rec significantly decreased in F group from 38.0 °C (T0) to 37.4 °C (T40), 37.2 °C (T50) and 36.9 °C (T60), in MF group from 38.3 °C (T0) to 37.5 °C (T50) and 37.4 °C (T60) and in AF group from 38.2 °C (T0) to 37.6 °C (T40), 37.5 °C (T50) and 37.4 °C (T60). CONCLUSIONS AND CLINICAL RELEVANCE: Premedication with fentanyl, medetomidine-fentanyl or acepromazine-fentanyl in the doses used decreased the T-Oeso and T-Rec. The T-Oeso at the beginning of anaesthesia was higher after premedication with medetomidine-fentanyl. However, this difference was not clinically significant.

EVALUATION OF A BUTORPHANOL-MIDAZOLAM-MEDETOMIDINE PROTOCOL FOR SHORT PROCEDURES IN LESSER CHEVROTAINS (TRAGULUS SP.).

Twenty lesser chevrotains (Tragulus sp.), 10 males and 10 females, were anesthetized with a combination of butorphanol-midazolam-medetomidine (BMidM), to assess the efficacy of this protocol for short procedures in this genus. The animals received BMidM (0.32, 0.06, 0.15 mg/kg, respectively) intramuscularly via hand injection. Physiological variables were recorded once the animals reached a working depth of anesthesia that lasted 30 min (range 12-60 min). At the end of the procedure, medetomidine and butorphanol were antagonized with atipamezole (0.75 mg/kg) and naltrexone (0.3 mg/kg) intramuscularly, respectively. Induction and recovery were 9.4 ± 4.0 min and 10.2 ± 4.1 min, respectively. Supplementation with isoflurane via face mask was required in five animals to reach light anesthesia. Times to reach the various stages of anesthesia were compared between sexes. There was no difference between males and females reaching the different stages of anesthesia, except for the time required to reach the ambulatory stage, in which females took a significantly longer time (11.8 min vs 7.8 min for the males) to stand after the injection of the antagonists (P = 0.02). Heart rate, respiratory rate, rectal temperature, and peripheral hemoglobin oxygen saturation were similar between sexes and stable throughout the procedure. At the dosage tested BMidM was a reliable and safe protocol for short, minimally invasive procedures in lesser chevrotains with a fast induction and smooth recovery without complications.

TILETAMINE-ZOLAZEPAM-XYLAZINE ANESTHESIA IN EX SITU BLACK-HANDED SPIDER MONKEYS (ATELES GEOFFROYI SSP.).

Black-handed spider monkeys (Ateles geoffroyi ssp.) are endangered in Mexico. Safe anesthetic protocols are important for in situ and ex situ conservation problems. Such protocols are scarce in the literature; nor have safety and physiologic responses been reported. High doses and volume are a counter side for field immobilizations. We tested an anesthetic protocol with a combination of tiletamine-zolazepam (5 mg/kg) plus xylazine (1 mg/kg) in 14 black-handed spider monkeys under human care from two facilities in Mexico. Physiological parameters such as HR, RR, T, SPO2, systolic arterial pressure (), diastolic arterial pressure (DAP), and median arterial pressure (MAP) were obtained. HR and RR decreased over time, but T increased significantly during the anesthetic time for the whole group; RR and T decreased for juveniles only. Variation between individuals was observed for HR, RR, and DAP. Volume reduction of drugs was achieved compared to previously reported anesthesia protocols. Induction time was fast (6.2 ± 10.4 min) and no tail prehension was seen. Recovery was prolonged (mean and SD). Physiologic parameters remained stable throughout. The protocol proved to be safe for the chemical immobilization of black-handed spider monkeys.

Neurodevelopmental Outcomes after Premedication with Atropine/Propofol vs Atropine/Atracurium/Sufentanil for Neonatal Intubation: 2-Year Follow-Up of a Randomized Clinical Trial.

This study followed 173 newborn infants in the PREmedication Trial for Tracheal Intubation of the NEOnate multicenter, double-blind, randomized controlled trial of atropine-propofol vs atropine-atracurium-sufentanil for premedication before nonemergency intubation. At 2 years of corrected age, there was no significant difference between the groups in death or risk of neurodevelopmental delay assessed with the Ages and Stages Questionnaire. Trial registration Clinicaltrials.gov: NCT01490580.

Evaluation of anaesthetic and cardiorespiratory effects after intramuscular administration of alfaxalone alone, alfaxalone-ketamine and alfaxalone-butorphanol-medetomidine in common marmosets (Callithrix jacchus).

BACKGROUND: Anaesthesia is often required in common marmosets undergoing various procedures. The aim of this study was to evaluate anaesthetic and cardiopulmonary effects of alfaxalone, alfaxalone-ketamine and alfaxalone-butorphanol-medetomidine in common marmosets. METHODS: The following treatments were repeatedly administered to seven female common marmosets: Treatment A, alfaxalone (12 mg kg-1 ) alone; treatment AK, alfaxalone (1 mg animal-1 ) plus ketamine (2.5 mg animal-1 ); treatment AMB, alfaxalone (4 mg kg-1 ), medetomidine (50 µg kg-1 ) plus butorphanol (0.3 mg kg-1 ); and treatment AMB-Ati, AMB with atipamezole at 45 minutes. RESULTS AND CONCLUSIONS: Marmosets became laterally recumbent and unresponsive for approximately 30 minutes in A and AK and for approximately 60 minutes in AMB. The animals showed rapid recovery following atipamezole injection in AMB-Ati. The decrease in heart rate and SpO2 was significantly greater in AMB compared to A and AK. Oxygen supplementation, anaesthetic monitors and atipamezole should be available especially when AMB is administered.

Different Reactions of Zebra Finches and Bengalese Finches to a Three-Component Mixture of Anesthetics.

Kawai et al. (2011) recently introduced a mixture of three anesthetic agents (here called MMB) that has an effect similar to ketamine/xylazine in mice, which might allow more effective reaction to changes in the animal condition, as an antagonist is available, and which can be used without license for handling narcotic drugs. Using Kawai's study as a baseline, we tested whether this anesthesia and its antagonist can also be used in avian studies. In the present study, we used two species, the zebra finch and the Bengalese finch, of the avian family Estrildidae. In zebra finches, anesthesia effects similar to the use of ketamine/xylazine and to those obtained in mice can be reached by the use of MMB if a higher dose is applied. MMB leads to more variable anesthesia, but has the advantage of a longer time window of deep anesthesia. An antagonist to one component of MMB reduced the awaking time, but was not as effective as in mice. For Bengalese finches, MMB cannot be generally recommended because of difficult handling and high mortality rate when used without antagonist, but could be used for perfusions instead of pentobarbital.

Total injectable anesthesia of dogs and cats for remote location veterinary sterilization clinic.

BACKGROUND: Sterilization clinics often occur in remote places where anesthesia machines and compressed oxygen are unavailable. This study describes the use of total injectable anesthesia in dogs and cats presented for sterilization in a remote location. RESULTS: A total of 100 animals were sterilized; 26 female cats (CF), 22 male cats (CM), 28 female dogs (DF), and 24 male dogs (DM). CF were anesthetized with dexmedetomidine (20 mcg/kg), ketamine (8 mg/kg) and hydromorphone (0.1 mg/kg) IM. CM were anesthetized with dexmedetomidine (15 mcg/kg), ketamine (5 mg/kg) and hydromorphone (0.1 mg/kg) IM. Insufficient anesthesia in cats was treated with alfaxalone (1 mg/kg) IM. All cats were administered meloxicam at 0.3 mg/kg SQ. DF were anesthetized with dexmedetomidine (15 mcg/kg), ketamine (7-10 mg/kg) and hydromorphone (0.1 mg/kg) IM. DM were anesthetized with dexmedetomidine (15 mcg/kg), ketamine (5 mg/kg) and hydromorphone (0.1 mg/kg) IM. All dogs had IV catheter and endotracheal tube placed. If SpO2 < 91%, ventilation was assisted with an Ambu bag. Insufficient anesthesia in dogs was treated with alfaxalone (1 mg/kg) IV. All dogs were administered meloxicam at 0.2 mg/kg SQ. Following surgery, atipamezole (0.05-0.1 mg/kg) IM was administered to any patient that did not have voluntary movement. All patients survived and were discharged. Less than 25% of cats and male dogs required supplemental anesthesia. Fifty seven percent of female dogs required supplemental anesthesia. More than 89% of patients (in any group) required atipamezole administration. One cat recovered with agitation and hyperthermia (41.1C/ 106F). Some dogs required ventilatory assistance to remain normoxemic while anesthetized. CONCLUSION: Total injectable anesthesia can be accomplished for remote location sterilization clinics with minimal morbidity.

Lidocaine Reduces Sevoflurane Consumption and Improves Recovery Profile in Children Undergoing Major Spine Surgery.

BACKGROUND Intravenous lidocaine administered during surgery improves postoperative outcomes; however, few studies have evaluated the relationship between intravenous lidocaine and volatile anesthetics requirements. This study assessed the effects of lidocaine treatment on sevoflurane consumption and postoperative consciousness disorders in children undergoing major spine surgery. MATERIAL AND METHODS Patients were randomly divided into 2 treatment groups: lidocaine and placebo (control). The lidocaine group received lidocaine as a bolus of 1.5 mg/kg over 30 min, followed by a continuous infusion at 1 mg/kg/h to 6 h after surgery. The following data were assessed: end-tidal sevoflurane concentration required to maintain a bispectral index BIS between 40 and 60, intraoperative blood pressure, heart rate, demand for fentanyl, and consciousness level assessed after surgery using the Richmond Agitation-Sedation Scale. Any treatment-related adverse events were recorded. RESULTS Compared to the control group, lidocaine treatment reduced by 15% the end-tidal sevoflurane concentration required to maintain the intraoperative hemodynamic stability and appropriate level of anesthesia (P=0.0003). There were no intergroup differences in total dose of fentanyl used, average mean arterial pressure, or heart rate measured intraoperatively. The postoperative level of patient consciousness did not differ during the first 6 h between groups. After 9 h, more patients in the control group were still sleepy (P=0.032), and there were fewer perioperative complications in the lidocaine group. CONCLUSIONS Lidocaine treatment decreases sevoflurane consumption and improves recovery profiles in children undergoing major spine surgery.

Influence of Topical Anesthesia on Superficial Sensitivity: A Double-Blind, Randomized, Placebo-Controlled Study on 48 Healthy Subjects.

BACKGROUND: Topical anesthetics are used in noninvasive transdermal anesthesia to decrease the superficial pain sensation threshold during dermatologic surgery. Combined pain relief and sensitivity loss can avoid discomfort during the surgery. OBJECTIVE: The aim of this placebo-controlled study was to compare the efficacy of 3 commonly used topical agents by collating loss of sensitivity over time. MATERIALS AND METHODS: Three topical anesthetic creams, a topical anti-inflammatory cream, and a moisturizing cream were applied on the left volar forearm of each of the 48 healthy Caucasian participants. Sensitivity was assessed with the dynamic 2-point discrimination and the Semmes-Weinstein test at 0, 60, 90, 120, 150, and 180 minutes after cream application. RESULTS: After 180 minutes, benzocaine showed a significantly lower 2-point discrimination reduction than lidocaine alone and a lidocaine and prilocaine mixture. Sensory threshold measurements by the Semmes-Weinstein test after 60 minutes revealed a significantly higher effect with lidocaine alone and with the lidocaine and prilocaine mixture than with benzocaine. CONCLUSION: The authors found a stronger skin sensitivity reduction by the eutectic lidocaine and prilocaine mixture and lidocaine alone compared with benzocaine. We suggest increased discomfort reduction in topical anesthetic supported dermatologic surgery by the eutectic mixture and lidocaine alone.

Cross-sectional survey of anaesthesia and analgesia protocols used to perform routine canine and feline ovariohysterectomies.

OBJECTIVE: To collect baseline descriptive data on the anaesthesia and analgesia protocols used by New Zealand veterinarians in first-opinion practice when performing routine canine and feline ovariohysterectomies. STUDY DESIGN: Cross-sectional survey. ANIMALS: Not applicable. METHODS: An online survey was conducted asking respondents for: 1) preoperative patient assessment; 2) preanaesthetic medication and induction drugs used; 3) anaesthesia maintenance drug choices and monitoring equipment used; and 4) postoperative analgesia drug selections and monitoring for ovariohysterectomy performed in healthy adult dogs and cats. RESULTS: The survey was completed by 472 veterinarians, of whom 282 provided responses for canine ovariohysterectomy and 361 provided responses for feline ovariohysterectomy. Approximately 23% of canine ovariohysterectomies and 13% of feline ovariohysterectomies had preanaesthetic bloodwork performed. There were 74 unique premedication/induction drug combinations reported for canine ovariohysterectomies and 94 for feline ovariohysterectomies. The most commonly used drug combinations were acepromazine, morphine ± propofol and butorphanol, ketamine and medetomidine for canine and feline ovariohysterectomies respectively. Most animals were intubated, and anaesthesia was maintained with isoflurane in oxygen. Use of intravenous catheters, fluid administration, heat support, and monitoring equipment varied. There were 41 unique postoperative analgesia drug combinations reported for canine ovariohysterectomies and 20 for feline ovariohysterectomies. Canine ovariohysterectomies were most commonly administered injectable opioids on the day of surgery followed by 3 days of oral non-steroidal anti-inflammatory drugs (NSAIDs), whereas feline ovariohysterectomies were usually administered a single injection of an opioid or NSAID or both on the day of surgery. Most animals were seen within 7-10 days for re-examination and/or suture removal. CONCLUSIONS AND CLINICAL RELEVANCE: Veterinarians use a wide range of anaesthesia and analgesia protocols for routine ovariohysterectomies. Further research is needed comparing the safety and efficacy of commonly used protocols to determine whether there are opportunities to improve the level of patient welfare.

Sedative effects of two doses of alfaxalone in combination with methadone and a low dose of dexmedetomidine in healthy Beagles.

OBJECTIVE: To evaluate the sedative effects of two doses of alfaxalone when added to a combination of dexmedetomidine and methadone injected intramuscularly (IM) in healthy Beagles. STUDY DESIGN: Randomized, blinded, crossover, experimental study. ANIMALS: A group of six adult Beagles. METHODS: Dogs were sedated on three different occasions with IM dexmedetomidine (3 µg kg-1) and methadone (0.3 mg kg-1) combined with two doses of alfaxalone (0.5 and 1 mg kg-1; A0.5 and A1, respectively) or saline (A0). Quality of sedation, response to tail clamping and rectal temperature were recorded at baseline, 5, 15, 25, 35 and 45 minutes. Pulse and respiratory rates, oxygen saturation of haemoglobin (SpO2) and noninvasive blood pressure (NIBP) were recorded every 5 minutes. Onset of sedation and duration of recumbency, response to venous catheterization and recovery quality were assessed. Physiological variables (analysis of variance) were analysed between treatments and within treatments compared with baseline (Student t test). Nonparametric data were analysed using Friedman and Cochran's Q tests. Significance was p < 0.05. RESULTS: Sedation scores were significantly higher when alfaxalone was co-administered (area under the curve; p = 0.024, A0.5; p = 0.019, A1), with no differences between doses. Onset of sedation was similar, but duration of recumbency was longer in A0.5 than in A0 [median (minimum-maximum), 43 (35-54) versus 30 (20-47) minutes, p = 0.018], but not in A1. Response to venous catheterization and tail clamping, and quality of recovery (acceptable) presented no differences between treatments. A decrease in all physiological variables (compared with baseline) was observed, except for NIBP, with no differences between treatments. All dogs required oxygen supplementation due to reduced SpO2. CONCLUSIONS AND CLINICAL RELEVANCE: Adding alfaxalone to methadone and dexmedetomidine enhanced sedation and duration of recumbency. Although cardiopulmonary depression was limited, oxygen supplementation is advisable.

Combined spinal epidural for labour analgesia and caesarean section: indications and recommendations.

PURPOSE OF REVIEW: Even if its use is scarce in most countries, many articles concerning combined spinal epidural (CSE) were published. In this review, we present the latest advances concerning CSE in obstetrics. RECENT FINDINGS: During labour, CSE improves epidural analgesia quality. Epidural with intradural opioids can produce maternal hypotension and foetal heart rate abnormalities (FHR-Ab), without increasing the caesarean section rate. For caesarean section, CSE decreases the neuraxial block failure rate, with no significant increase of complications. Epidural volume extension (EVE) after CSE for caesarean section could be an interesting option even though more evidence is needed. SUMMARY: For labour analgesia, CSE has the fastest onset time of analgesia. Its side effects have no consequences on maternal, labour or foetal outcomes. It provides better analgesia than epidural analgesia and can be used for external cephalic version and high-risk patients. For caesarean section, CSE has become the reference neuraxial technique for low-dose spinal anaesthesia, with higher success rate compared with regular spinal anaesthesia. Recent systematic revisions did not confirm this superiority. CSE offers the advantage of EVE, intraoperative top-ups, postoperative administration of neuraxial opioids and local anaesthetics. The risk of complications is balanced by the benefits of the technique.

EVALUATION OF TWO DOSES OF BUTORPHANOL-MEDETOMIDINE-MIDAZOLAM FOR THE IMMOBILIZATION OF WILD VERSUS CAPTIVE BLACK-FOOTED CATS (FELIS NIGRIPES).

The efficacy, safety, physiologic effects, and reversibility of butorphanol-medetomidine-midazolam (BMM) immobilization were evaluated in black-footed cats (Felis nigripes) and compared between captive and wild animals. Nine captive and 14 wild black-footed cats were hand injected into an accessible hind limb muscle group with the BMM combination. The captive cats (captive group) received a lower dose of the combination (butorphanol, 0.25 ± 0.03 mg/kg; medetomidine, 0.06 ± 0.01 mg/kg; midazolam, 0.13 ± 0.02 mg/kg), whereas the wild cats received a higher dose (butorphanol, 0.53 ± 0.11 mg/kg, medetomidine, 0.13 ± 0.03 mg/kg, midazolam, 0.27 ± 0.05 mg/kg). Two capture methods were required to restrain the wild cats; previously collared cats were tracked and excavated out of their burrows during daylight hours (excavated group), whereas uncollared cats were randomly located using spotlights and pursued by a vehicle at night (pursued group). Inductions were rapid and no spontaneous arousals occurred. Mean arterial blood pressure in all cats was within normal limits for domestic cats. Initial rectal temperatures varied greatly among the groups, but decreased in all groups as the immobilization progressed. In the pursued animals, heart rates and respiratory rates were initially elevated. All cats had moderate hypoxemia, hypocapnia, and metabolic acidosis. Intramuscular administration of naltrexone, atipamezole, and flumazenil resulted in rapid, uncomplicated recoveries. BMM is thus a safe, effective immobilizing drug combination for both captive and wild black-footed cats, but higher doses are required in wild animals. The capture methods exerted a greater influence on the physiology of the immobilized animals than did the doses of the drugs used. Although this drug combination can be used safely to immobilize black-footed cats, supplemental oxygen should always be available for use, especially in pursued animals due to hypoxia.

ANESTHESIA WITH MEDETOMIDINE-KETAMINE AND DEXMEDETOMIDINE-KETAMINE IN MOUNTAIN GORILLAS (GORILLA BERINGEI BERINGEI).

Between December 2002 and September 2017, 125 anesthetic procedures involving free-living and orphaned captive mountain gorillas (Gorilla beringei beringei) were performed in the Virunga Massif and Bwindi Impenetrable Forest in East-Central Africa. Of these 125 immobilizations, 114 records were complete enough for inclusion into this study. Anesthetic and physiologic data from these 114 cases were analyzed, of which 57 used medetomidine-ketamine and 57 used dexmedetomidine-ketamine administered intramuscularly. With the use of estimated weights, the mean induction dosage (mg/kg ± SD) for medetomidine was 0.033 ± 0.003 (n = 42), for dexmedetomidine 0.018 ± 0.005 (n = 53), and for ketamine 3.66 ± 0.95 (n = 95). Mean time from injection of induction dose to recumbency was 6.8 ± 3.1 min (n = 74). Atipamezole was administered intramuscularly to reverse anesthesia. First signs of recovery occurred at 5.0 ± 4.0 min, and full recovery was 19.0 ± 17.0 min after administration of the reversal agent. No significant differences in physiologic parameters or anesthetic time variables were noted between healthy and unhealthy individuals. Mean heart rate was 72.0 ± 17.6 beats/min (n = 83) and mean oxygen saturation was 96.5% ± 4.2 (n = 62). Mean respiratory rate was 27 ± 9 breaths/min (n = 84) and mean body temperature 36.6°C ± 1.2 (n = 61). The current protocol has several advantages for field use in this species given its quick induction, few observed side effects, and ability to reverse so that the animal can return more quickly to its social group.

ANESTHESIA AND SURGERY PROTOCOLS FOR INTRA-ABDOMINAL TRANSMITTER PLACEMENT IN FOUR SPECIES OF WILD ARMADILLO.

The anatomy and physiology of armadillos make anesthetic procedures and the placement of telemetry devices challenging. From June 2011 to November 2019, a total of 73 free-living armadillos were captured and anesthetized in the Pantanal, Brazil. Giant (Priodontes maximus), six-banded (Euphractus sexcinctus), southern naked-tailed (Cabassous unicinctus), and nine-banded (Dasypus novemcinctus) armadillos were divided into two groups. In group 1, 30 armadillos were anesthetized for collection of biological samples, body measurements, and placement of a microchip tag. Anesthetic combination BDM was applied: butorphanol tartrate, detomidine hydrochloride, and midazolam hydrochloride, each at 0.1 mg/kg. In group 2, 43 armadillos received ketamine hydrochloride at 10 mg/kg 20 min after BDM injection, and intra-abdominal radio transmitters were surgically implanted. The transmitter was inserted freely into the abdominal cavity. Vital signs were monitored during anesthesia every 10 min and varied within species and between groups. Rectal temperature varied from 33.1 ± 1.36 to 35.34 ± 1.21°C, heart rate (beats/min) from 19 ± 2.14 to 84.71 ± 9.25, respiratory rate (breaths/min) from 11 ± 4.16 to 31 ± 2.82, and oxygen saturation values (SPO2%) from 84.17% ± 2.39 to 98% ± 1.20. Both groups received the antagonist combination NYF: naloxone hydrochloride (0.02 mg/kg), yohimbine hydrochloride (0.125 mg/kg), and flumazenil (0.01 mg/kg). Recovery varied according to intravenous or intramuscular injection from 2 ± 4 to 8.08 ± 2.93 min respectively. BDM protocol was considered satisfactory and provided enough time to complete the procedures (60 ± 85 to 133.20 ± 9.12 min) according to the species and group. Ketamine added to the BDM provided enough time and a surgical plane of anesthesia (97 ± 22 to 137 ± 39.5 min). The surgical procedure technique chosen did not appear to have a negative impact on armadillos studied. Implantable transmitters provide a cost-effective method for long-term monitoring of wild individuals.

FACTORS AFFECTING TEAR PRODUCTION AND INTRAOCULAR PRESSURE IN ANESTHETIZED CHIMPANZEES (PAN TROGLODYTES).

Measurements of intraocular pressure (IOP) and tear production are key components of ophthalmic examination. Chimpanzees (Pan troglodytes) were anesthetized using either tiletamine-zolazepam (TZ; 2 mg/kg) combined with medetomidine (TZM; 0.02 mg/kg), or, TZ alone (6mg/kg). Tear production was lower (P = 0.03) with TZM (5.63 ± 6.22 mm/min; n = 16) than with TZ (11.13 ± 4.63 mm/min; n = 8). Mean IOP, measured using rebound tonometry in an upright body position (n = 8) was 18.74 ± 3.01 mm Hg, with no differences between right and left eyes. However, positioning chimpanzees in left lateral recumbency (n = 27) resulted in higher IOP in the dependent (left) eye (24.77 ± 4.49 mm Hg) compared to the nondependent (right) eye (22.27 ± 4.65 mm Hg) of the same animal (P < 0.0001). These data indicate medetomidine anesthesia markedly lowers tear production in chimpanzees, and that body position should be taken into consideration when performing rebound tonometry.

Stellate ganglion block and cardiac sympathetic denervation in patients with inappropriate sinus tachycardia.

BACKGROUND: Inappropriate sinus tachycardia (IST) remains a clinical challenge because patients often are highly symptomatic and not responsive to medical therapy. OBJECTIVE: To study the safety and efficacy of stellate ganglion (SG) block and cardiac sympathetic denervation (CSD) in patients with IST. METHODS: Twelve consecutive patients who had drug-refractory IST (10 women) were studied. According to a prospectively initiated protocol, five patients underwent an electrophysiologic study before and after SG block (electrophysiology study group). The subsequent seven patients had ambulatory Holter monitoring before and after SG block (ambulatory group). All patients underwent SG block on the right side first, and then on the left side. Selected patients who had heart rate reduction ≥15 beats per minute (bpm) were recommended to consider CSD. RESULTS: The mean (SD) baseline heart rate (HR) was 106 (21) bpm. The HR significantly decreased to 93 (20) bpm (P = .02) at 10 minutes after right SG block and remained significantly slower at 97(19) bpm at 60 minutes. Left SG block reduced HR from 99 (21) to 87(16) bpm (P = .02) at 60 minutes. SG block had no significant effect on blood pressure or HR response to isoproterenol or exercise (all P > .05). Five patients underwent right (n = 4) or bilateral (n = 1) CSD. The clinical outcomes were heterogeneous: one patient had complete and two had partial symptomatic relief, and two did not have improvement. CONCLUSION: SG blockade modestly reduces resting HR but has no significant effect on HR during exercise. Permanent CSD may have a modest role in alleviating symptoms in selected patients with IST.

Retroclavicular vs supraclavicular brachial plexus block for distal upper limb surgery: a randomised, controlled, single-blinded trial.

BACKGROUND: Regional anaesthesia for upper limb surgery is routinely performed with brachial plexus blocks. A retroclavicular brachial plexus block has recently been described, but has not been adequately compared with another approach. This randomised controlled single-blinded trial tested the hypothesis that the retroclavicular approach, when compared with the supraclavicular approach, would increase the success rate. METHODS: One hundred and twenty ASA physical status 1-3 patients undergoing distal upper limb surgery were randomised to receive an ultrasound-guided retroclavicular or supraclavicular brachial plexus block with 30 mL of a 1:1 mixture of mepivacaine 1% and ropivacaine 0.5%, using a single-injection technique without needle tip repositioning. The primary outcome was block success rate 30 min after local anaesthetic injection, defined as a composite score of 14 of 16 points, inclusive of sensory and motor components. Secondary outcomes included needling time, time to first opioid request, oxycodone consumption, and pain scores (numeric rating scale, 0-10) at 24 h postoperatively. RESULTS: Success rates were 98.3% [95% confidence interval (CI): 90.8%, 99.9%] and 98.3% [95% CI: 90.9%, 99.9%] in the supraclavicular and retroclavicular groups, respectively (P=0.99). The mean needling time was reduced in the supraclavicular group [supraclavicular: 5.0 (95% CI: 4.7, 5.4) min; retroclavicular: 6.0 (95% CI: 5.4, 6.6) min; P=0.006]. The mean time to first opioid request was similar between groups [supraclavicular: 439 (95% CI: 399, 479) min; retroclavicular: 447 (95% CI: 397, 498) min; P=0.19] as were oxycodone consumption [supraclavicular: 10.0 (95% CI: 6.5, 13.5 mg; retroclavicular: 7.9 (95% CI: 4.8, 11.0) mg; P=0.80] and pain scores at 24 h postoperatively [supraclavicular: 1.2 (95% CI: 2.1, 2.7); retroclavicular: 1.5 (95% CI: 1.6, 2.4); P=0.09]. CONCLUSIONS: Ultrasound-guided retroclavicular and supraclavicular brachial plexus blocks share identical success rates, while providing similar pain relief. Reduced needling time in the supraclavicular approach is not clinically relevant. CLINICAL TRIAL REGISTRATION: NCT02641613.