How to plan and provide general anesthesia for a troop of 98 hamadryas baboons (Papio hamadryas) for contraceptive and preventative health interventions.

OBJECTIVE: Present an approach to the safe and efficient provision of anesthesia and birth control measures to a large group of primates. ANIMALS: 98 hamadryas baboons (Papio hamadryas) held in a German zoological institution. METHODS: A group of 12 veterinarians, 2 zookeepers, and 6 volunteers anesthetized all animals within 2 days. The baboons were orally premedicated with midazolam (0.1 to 0.5 mg/kg) and anesthetized with medetomidine (40 to 60 µg/kg, IM) and ketamine (2 to 4 mg/kg, IM); isoflurane at rates of 1.5% to 2% was used for maintaining anesthesia if necessary. All animals received a physical examination, prophylactic medication, and tuberculin testing. For population management, the animals received a contraceptive implant (adult females), orchiectomy (young males), or vasectomy (breeding males). Young males received intratesticular blocks with lidocaine. All animals received atipamezole (125 to 150 µg/kg) before recovery. RESULTS: Premedication resulted in anxiolysis, which facilitated separating and darting. Median time from darting to access to the animal was 10 minutes. Mean anesthetic times were 25 minutes for females and 55 minutes for males. The depth of anesthesia was appropriate for the procedures. No fatalities were recorded. One animal was injured by other baboons but recovered after treatment. CLINICAL RELEVANCE: Health management and birth control measures are necessary in baboon troops under human care. Anesthesia and/or contraception of individual animals often leads to intraspecific aggression. This case series describes how to provide anesthesia and contraception to an entire troop as an alternative approach that can be adopted to future similar interventions.

Agreement of High-Definition Oscillometry (HDO) and Invasive Blood Pressure Measurements at a Metatarsal Artery in Isoflurane-Anaesthetised Horses.

High-definition oscillometry (HDO) over the metatarsal artery (MA) in anaesthetised horses has not yet been evaluated. This study aimed to assess agreement between HDO and invasive blood pressure (IBP) at the metatarsal artery, and to evaluate compliance with the American College of Veterinary Internal Medicine (ACVIM) consensus guidelines. In this experimental study, 11 horses underwent general anaesthesia for an unrelated, terminal surgical trial. Instrumentation included an IBP catheter in one and an HDO cuff placed over the contralateral MA, as well as thermodilution catheters. Systolic arterial pressure (SAP), mean arterial pressure (MAP), diastolic arterial pressure (DAP), and cardiac output were measured simultaneously. Normotension (MAP 61-119 mmHg) was maintained during the surgical study. Subsequently, hypotension (MAP ≤ 60 mmHg) and hypertension (MAP ≥ 120 mmHg) were induced pharmacologically. For MAP, the agreement between HDO and IBP was acceptable during normotension, while during hypotension and hypertension, IBP was overestimated and underestimated by HDO, respectively. The monitor failed to meet most ACVIM validation criteria. Consequently, if haemodynamic compromise or rapid blood pressure changes are anticipated, IBP remains preferable.

Odd haemoglobins in odd-toed ungulates: Impact of selected haemoglobin characteristics of the white rhinoceros (Ceratotherium simum) on the monitoring of the arterial oxygen saturation of haemoglobin.

BACKGROUND: Due to the current poaching crisis in Africa, increasing numbers of white rhinoceroses (Ceratotherium simum) require opioid immobilisation for medical interventions or management procedures. Alarmingly, the results of both blood gas analysis and pulse oximetry regularly indicate severe hypoxaemia. Yet, the recovery of the animals is uneventful. Thus, neither of the techniques seems to represent the real oxygenation level. We hypothesized that unusual haemoglobin characteristics of this species interfere with the techniques developed and calibrated for the use in human patients. METHODS: Haemoglobin was isolated from blood samples of four adult, white rhinoceroses. Oxygen dissociation curves at pH 7.2 and 7.4 (37°C) were determined based on the absorbance change of haemoglobin in the Soret-region (around 420 nm). Absorbance spectra of oxy- and deoxyhaemoglobin extending into the infrared region were measured. RESULTS: Oxygen dissociation curves of rhinoceros haemoglobin showed the typical high oxygen affinity (p50 of 2.75 ± 0.07 and 2.00 ± 0.04 kPa for pH 7.2 and 7.4, respectively) under near-physiological conditions with respect to pH, temperature and DPG. The infrared absorbance spectra of oxy- and deoxyhaemoglobin showed only marginal deviations from standard human spectra, possibly due to the presence of a few percent of methaemoglobin in vitro. CONCLUSIONS: Our data enables the development of a rhinoceros-specific blood gas analysis algorithm, which allows for species-specific calculation of SaO2 levels in anaesthetized animals. The inconspicuous absorbance spectra do not contribute to the systematic underestimation of SpO2 by pulse-oximetry.