Current Techniques in Avian Anesthesia

Balanced anesthesia in pigeons (Columba livia): a protocol that ensures stable vital parameters and feasibility during long surgeries in cognitive neuroscience

In neuroscience, numerous experimental procedures in animal models require surgical interventions, such as the implantation of recording electrodes or cannulas before main experiments. These surgeries can take several hours and should rely on principles that are common in the field of research and medicine. Considering the characteristics of the avian respiratory physiology, the development of a safe and replicable protocol for birds is necessary to minimize side effects of anesthetic agents, circumvent technical limitations due to the insufficient availability of patient monitoring, and to maintain stable intraoperative anesthesia. Through the consistent and responsible implementation of the three R principle of animal welfare in science ("Replace, Reduce, Refine"), we aimed to optimize experimental methods to minimize the burden on pigeons (Columba livia) during surgical procedures. Here, surgeries were conducted under balanced anesthesia and perioperative monitoring of heart rate, oxygen saturation, body temperature, and the reflex state. The protocol we developed is based on the combination of injectable and inhalative anesthetic drugs [ketamine, xylazine, and isoflurane, supported by the application of an opiate for analgesia (e.g., butorphanol, buprenorphine)]. The combination of ketamine and xylazine with a pain killer is established in veterinary medicine across a vast variety of species. Practicability was verified by survival of the animals, fast and smooth recovery quantified by clinical examination, sufficiency, and stability of anesthesia. Independent of painful stimuli like incision or drilling, or duration of surgery, vital parameters were within known physiological ranges for pigeons. Our approach provides a safe and conservative protocol for surgeries of extended duration for scientific applications as well as for veterinary medicine in pigeons which can be adapted to other bird species.

Validation of enzyme immunoassays for quantifying sex steroid hormones in tropical screech owls (Megascops choliba)

Androgens and estrogens are steroid hormones that regulate reproductive processes in both males and females. Monitoring plasma levels of these steroids or their metabolites present in feces, offers diagnostic support for assessing the reproductive status of animals. Immunoassays are commonly used methods for quantifying these hormones, but their protocols require species-specific validation to ensure reliability. The objective of this study was to perform analytically and biologically validation of enzyme immunoassay (EIA) kits for measuring testosterone (T), estradiol (E2), faecal androgen metabolites (fAM), and faecal estrogenic metabolites (fEM) in the tropical screech owl (Megascops choliba). Serum and fecal samples were collected from six adult females and six males both before and during breeding season, with males' gonadal activity assessed using electroejaculation (EE). The parallelism test confirmed the immunogenic similarity of the antigens in the estradiol and testosterone standards and the antigens in the serum samples and fecal extracts of M. choliba. Additionally, the EIA kits displayed nearly 100% recovery rates, and showed coefficients of variation ranging from 8% to 14% at the intra-assay level and from 10% to 16% at the inter-assay level, underscoring result reliability and consistency. In males, the highest serum T and fAM levels were recorded concurrently with the presence of spermatozoa in samples collected via EE. Although females did not exhibit oviposition events, significantly higher E2 and fEM levels were observed in August compared to May, suggesting potential seasonal variations in estrogenic hormone production. Fecal androgen and estrogen levels were significantly different between sexes in August, with males having higher fAM and females having higher fEM levels. Overall, the immunoassays validated in this study were found to be efficient in diagnosing reproductive activity in owls.

Cerebro-Cardiopulmonary Resuscitation and Postarrest Care in Exotic Animal Critical Care

Evidence-based recommendations for performing cardiopulmonary resuscitation (CPR) in domestic species provide a foundation for application to nondomestic species. The exotic and zoo practitioner must consider human safety, species anatomy, physiology, and special techniques for performing CPR. Having the hospital and team prepared and trained for a CPR response can improve outcomes. Basic life support includes various techniques for chest compressions and ventilation support. Advanced life support includes means of intravascular and intraosseous access, rescue drug administration, and consideration of the patient presenting circumstances. Team debriefs and support for mental wellness are useful to optimize performance and maintain team resiliency through CPR events.

Sedation and Anesthesia in Exotic Animal Critical Care

Sedation and anesthesia of exotic animals in inherently challenging, but often facilitates the best care for patients. Critical illness or injury adds on another layer of complexity to their management for obtaining diagnostics and providing treatments. This article serves to review some of the more recent literature of sedation and anesthesia within exotics practice, bringing to light some nuances and considerations for when those patients are critically ill or injured.

Retrospective evaluation of cardiopulmonary arrest and resuscitation in hospitalized birds: 41 cases (2006-2019)

OBJECTIVE

To describe circumstances and outcomes following cardiopulmonary arrest (CPA) in hospitalized birds.

DESIGN

Retrospective case study.

SETTING

Academic medical center.

METHODS

The hospital medical records system was searched for avian cases that underwent CPR. Medical records were reviewed; data retrieved included association of CPA with anesthesia or handling, use of external compressions and intubation, drug administration, rates of return of spontaneous circulation (ROSC), and outcome. Cases with incomplete medical records were excluded.

RESULTS

Forty-one cases of avian CPR were identified. Anesthesia-related arrest was reported in 26 of 41 cases. The remainder of CPA events occurred during an examination (6/41) or were observed during hospitalization for treatment of disease or injury (11/41). Compressions were performed in 14 birds and manual ventilation performed in 21 of 41 cases via intubation (19/21), tight-fitting face mask (1/21), or air sac cannulation (1/21). Vascular access was achieved in 24 of 41 cases. Emergency drug administration was documented in 22 of 41 cases and included epinephrine (20/22), atropine (19/22), glycopyrrolate (3/22), doxapram (2/22), dextrose (3/22), mannitol (1/22), and furosemide (1/22). Fluid therapy was administered in 24 of 41 cases. There were 3 documented cases of ROSC (7%), all in patients under general anesthesia, and 1 (2%) CPA survivor.

CONCLUSIONS

There was no standardized approach to avian CPR in this study, and ROSC was rare. When ROSC was achieved, birds were under general anesthesia with direct monitoring by a clinician, were ventilated, and were administered anesthetic reversals and anticholinergic or catecholamine emergency medications. These poor outcomes suggest that further research and an updated standardized approach to avian CPR, with special consideration of the physiological differences from mammals, are needed.

Comparison of the Anesthetic Effects of Isoflurane and Sevoflurane Inhalation on the Cardiovascular System of the Common Buzzard (Buteo buteo)

The aim of this study was to compare the effects of isoflurane (ISO) and sevoflurane (SEVO) inhalation anesthesia on the cardiovascular system of the common buzzard (Buteo buteo). Fourteen common buzzards of unknown sex and age, weighing 700-900 g each, were used for the study. The buzzards were randomly divided into an ISO group and a SEVO group, each comprising 7 buzzards. The buzzards were then anesthetized by masked induction with either ISO or SEVO. After induction, all buzzards were intubated with a 2.5-mm-diameter uncuffed endotracheal tube. Anesthesia was maintained with 3% ISO or 4% SEVO in a 3 L/min flow of 100% oxygen. Before induction, immediately after induction, and at intervals of 5, 10, 15, 20, 25, and 30 min after the patients were induced, the heart rate, respiratory rate, and body temperature of the buzzards were recorded. In addition, before and during anesthesia, serum electrolytes (sodium, ionized calcium, and potassium), blood gas measurements (arterial pH, arterial partial pressure of carbon dioxide, arterial partial pressure of oxygen, bicarbonate concentration, and oxyhemoglobin saturation), and hematocrit values were evaluated in the blood samples taken from both the ISO and SEVO groups. A statistically significant decrease in body temperature was observed in both groups. A significant decrease in heart rate was observed in the ISO group. The increases in partial pressure of carbon dioxide and bicarbonate concentration were statistically significant in both groups. The effects of ISO and SEVO anesthesia on the cardiovascular and respiratory system in the buzzards were similar based on the results of this study.

Injectable Anesthesia With Medetomidine, Ketamine, and Butorphanol in Captive Humboldt Penguins (Spheniscus humboldti)

The effects of an injectable anesthesia with 0.05 mg/kg medetomidine, 5 mg/kg ketamine, and 0.5 mg/kg butorphanol administered together intramuscularly were evaluated in 22 captive Humboldt penguins (Spheniscus humboldti, 10 male and 12 female), with a mean age of 8.5 ± 8.23 years. The birds fasted for18-24 hours prior to the procedure. Induction was followed by 4 distinct progressive responses of the birds to the anesthetic effect, including onset of initial effects at 2.0 ± 1.7 minutes (x̄ ± SD), sternal recumbency with the head still elevated at 2.2 ± 1.6 minutes, lowering and placing the beak tip to the ground at 3.6 ± 3.4 minutes, and lateral positioning of the neck and head at 4.2 ± 3.4 minutes. A general state of sedation, muscle relaxation, and analgesia were noted 10.0 ± 2.8 minutes postinjection. However, according to an established scoring system for the assessment of anesthetic depth in avian patients, a surgical plane of anesthesia was not achieved. Muscle relaxation determined by the same scoring system lasted for 31.4 ± 17.1 minutes. The penguins' mean respiratory rate did not demonstrate significant change and spontaneous ventilation was present throughout the procedure. Relative peripheral arterial oxygen saturation decreased significantly from 92.83 ± 5.77% at 10 minutes to 90.91 ± 5.77% at 40 minutes following induction. The birds' heart rate also decreased significantly from 112.55 ± 23.97 beats/min at 10 minutes to 101.65 ± 25.42 beats/min at 40 minutes. The measured cloacal temperatures were maintained within normal range despite ambient temperatures of up to 28.3°C (82.9°F). Reversal of medetomidine with 0.25 mg/kg atipamezole was conducted after 45.1 ± 7.3 minutes. Recovery was smooth but of variable duration with patients being able or willing to stand steadily in an upright position after 50.1 ± 34.6 minutes. One penguin died during recovery from a ruptured left ventricle and consecutive pericardial tamponade, but no predisposing factors were identified. The anesthetic protocol proved to be effective for noninvasive and minor painful procedures (eg, diagnostic imaging, blood collection). Disadvantages to the administration of the combined anesthetic agents in the penguins included a short period of muscle relaxation and smooth but potentially prolonged recovery. The safety of the anesthetic protocol described for Humboldt penguins in this report has to be evaluated critically against the the death of 1 penguin during recovery.

Comparative evaluation of isoflurane and sevoflurane in avian patients

Background and Aim:

Literature comparing the use of isoflurane and sevoflurane inhalation anesthetic agents in birds is scarce. This study aimed to evaluate the comparison of isoflurane and sevoflurane during induction, maintenance, and recovery of anesthesia in avian patients.

Materials and Methods:

In this study, 24 injured avian patients (n=24) were selected randomly and divided into four groups during kite flying festival. In the present study, isoflurane and sevoflurane were used as induction and maintenance anesthetic agents, with and without butorphanol tartrate premedication agent in all the birds. Different physiological parameters were evaluated, namely, cloacal temperature (°F), heart rate (beats/min), respiratory rate (breaths/min), and SpO₂ (%) were recorded at 0, 10, 20 min, and at recovery time. The quality of anesthesia was assessed on the basis of induction time, quality of induction, production of analgesia, muscle relaxation, body reflexes, recovery time, quality of recovery, sitting, standing, and complete recovery time (CRT).

Results:

The mean±standard error value of induction time was 230.00±32.55, 280.00±25.29, 180.00±21.90, and 260.00±36.87 s, respectively, in Groups I, II, III, and IV. The feather plucking, pharyngeal, and toe pinching reflexes were noticed, when the birds were passing through the light plane of anesthesia during induction. Comparison of cloacal temperature at the time of recovery between Group-I versus Group-III revealed a significant difference (p<0.05). Comparison of mean respiratory rates at the time of recovery between Group-II versus Group-IV revealed a significant difference (p<0.05). Excellent quality of recovery was observed in all the groups of anesthetic protocols. Sitting, standing, and CRT were observed shortest in avian patients maintained with sevoflurane as compared to isoflurane.

Conclusion:

The quality of induction of anesthesia was rapid in avian patients when induced with sevoflurane as compared to isoflurane. Rapid onset of induction and recovery of anesthesia were found with sevoflurane followed by isoflurane. Induction and maintenance of anesthesia in avian patients with sevoflurane resulted in the lowest time required for sitting, standing, and CRT.

Cardiorespiratory dose-response relationship of isoflurane in Cinereous vulture (Aegypius monachus) during spontaneous ventilation

Anesthesia is an inevitably important component of diagnosis and treatments examining the health condition of wild animals. Not only does anesthesia become an essential tool in minimizing stress of the patients and providing an opportunity to deliver accurate and safe procedures, but it also ensures the safety of the medical crew members. This study was conducted to investigate the dose-response cardiorespiratory effects of isoflurane during spontaneous ventilation in ten cinereous vultures. Each bird was administered isoflurane at initial concentration of 1.0, 1.5, 2.0, 2.5 and 3.0 and then an end-tidal isoflurane concentrations (ETiso) of 1.0% for an equilibration period of 15 min in the given order. At the end of the equilibration period, the direct blood pressure (BP), heart rate (HR), respiratory rate (RR) and end tidal CO₂ partial pressure (P_ETCO₂) were recorded, and blood gas analysis was performed. Increasing isoflurane concentrations during spontaneous ventilation led to dose-dependent increases in HR and P_ETCO₂, with minimal changes in RR, decreased arterial BP and respiratory acidosis. Overall, isoflurane for anesthesia of spontaneously breathing cinereous vultures is a suitable choice for diagnostic or surgical procedures.

EFEITOS ANESTÉSICOS DA ADMINISTRAÇÃO INTRANASAL OU INTRAMUSCULAR DA ASSOCIAÇÃO DE MIDAZOLAM E CETAMINA RACÊMICA OU S+ EM PERIQUITO AUSTRALIANO (Melopsittacus undulatus)

Resumo A anestesia intranasal em aves é considerada uma técnica anestésica segura, simples e eficiente. O objetivo deste estudo foi comparar os efeitos anestésicos da associação de midazolam (5 mg.kg-1) e cetamina (15 mg.kg-1) nas formulações racêmica (R) ou S+ (S) administrados pela via intranasal (IN) ou intramuscular (IM) em periquitos australianos (Melopsittacus undulatus). Foram utilizados oito periquitos em delineamento do tipo crossover, em quatro tratamentos: INR, INS, IMR e IMS. Foram avaliados os tempos de latência, decúbito dorsal, anestesia e recuperação, grau de sedação e qualidade de recuperação. Foi observada diferença significativa no tempo de latência entre INS (40,25±10,55 seg) e IMR (74,32±21,77 seg); entre as vias de administração para o tempo de decúbito dorsal, INS (23,93±7,51 min) e INR (28,68±16,13 min), diferente de IMS (60,08±27,37 min) e IMR (74,3±21,77 min) e para tempo de anestesia, INS (45,48±17,94 min) e INR (39,24±15,62 min), diferentes de IMS (75,84±20,20 min) e IMR (79,4±20,73 min). O tempo de recuperação foi significativamente maior em INS (21,55±18,43 min) comparado a IMR (5,1±3,56 min). Pode-se concluir que as duas vias de administração avaliadas podem ser utilizadas em procedimentos de curta duração e não invasivos e a via intranasal é preferível para procedimentos rápidos.

Cardiorespiratory parameters in the awake pigeon and during anaesthesia with isoflurane

OBJECTIVE

To determine baseline cardiovascular and respiratory variables in the awake pigeon, and to assess those variables during anaesthesia at the individual minimal anaesthetic concentration (MAC) of isoflurane during spontaneous breathing.

STUDY DESIGN

Prospective, experimental trial.

ANIMALS

Seven healthy adult pigeons weighing a mean ± standard deviation (SD) of 438 ± 38 g.

METHODS

Heart rate (HR), heart rhythm, respiratory rate (fR), end-expired carbon dioxide tension (Pe'CO2), indirect systolic arterial pressure (SAP) and cloacal temperature (T) were measured in birds in the awake state (after acclimatization to handling). Two weeks later, the pigeons were anaesthetized with isoflurane in order to determine their MAC and evaluate the same cardiovascular and respiratory variables during a further 40 minutes of isoflurane anaesthesia.

RESULTS

In the awake pigeon, mean ± SD HR, SAP, fR, Pe'CO2 and T were, respectively, 155 ± 28 beats minute(-1), 155 ± 21 mmHg, 34 ± 6 breaths minute(-1), 38 ± 8 mmHg (5.1 ± 1.1 kPa) and 41.8 ± 0.5 °C. Mean isoflurane MAC was 1.8 ± 0.4%. During maintenance of anaesthesia at MAC, although no significant decreases between values obtained in the awake and anaesthetized states emerged in HR or respiratory rate, significant decreases in SAP and cloacal temperature and an increase in Pe'CO2 were observed. No arrhythmia was identified in awake pigeons, whereas second- and third-degree atrioventricular blocks occurred under isoflurane.

CONCLUSIONS AND CLINICAL RELEVANCE

Isoflurane MAC in pigeons appeared to be higher than in other avian species. Isoflurane anaesthesia in pigeons resulted in hypercapnia, hypotension, mild hypothermia and second- and third-degree atrioventricular blocks.

Lactated Ringer's solution or 0.9% sodium chloride as fluid therapy in pigeons (Columba livia) submitted to humerus osteosynthesis

The study aimed to compare the effects of intraosseous infusion of lactated Ringer's and 0.9% sodium chloride solutions on the electrolytes and acid-base balance in pigeons submitted to humerus osteosynthesis. Eighteen pigeons were undergoing to isoflurane anesthesia by an avalvular circuit system. They were randomly assigned into two groups (n=9) receiving lactated Ringer's solution (LR) or 0.9% sodium chloride (SC), in a continuous infusion rate of 20mL/kg/h, by using an intraosseous catheter into the tibiotarsus during 60-minute anesthetic procedure. Heart rate (HR), and respiratory rate (RR) were measured every 10 min. Venous blood samples were collected at 0, 30 and 60 minutes to analyze blood pH, PvCO2, HCO3 -, Na+ and K+. Blood gases and electrolytes showed respiratory acidosis in both groups during induction, under physical restraint. This acidosis was evidenced by a decrease of pH since 0 min, associated with a compensatory response, observed by increasing of HCO3 - concentration, at 30 and 60 min. It was not observed any changes on Na+ and K+ serum concentrations. According to the results, there is no reason for choosing one of the two solutions, and it could be concluded that both fluid therapy solutions do not promote any impact on acid-base balance and electrolyte concentrations in pigeons submitted to humerus osteosynthesis.

Endotracheal intubation and oral gavage in the domestic chicken

The domestic chicken (Gallus gallus) is increasing in popularity as a laboratory animal, as it is useful in multiple fields of biomedical research and has the practical benefits of being relatively inexpensive, easy to handle and able to adapt to various settings. Here, we describe two procedures commonly used with chickens in research: endotracheal intubation and oral gavage.

The effect of premedication with ketamine, alone or with diazepam, on anaesthesia with sevoflurane in parrots (Amazona aestiva)

BACKGROUND

Premedication is rarely used in avian species. The aim of this study was to evaluate the effect of premedication on the quality of sevoflurane induction and anaesthesia in parrots. We hypothesised that premedication would facilitate handling and decrease the minimum anaesthetic dose (MAD). Thirty-six adult parrots were randomly distributed in three groups: group S (n = 12) was premedicated with NaCl 0.9%; group KS (n = 12) was premedicated with 10 mg.kg-1 ketamine; and group KDS (n = 12) was premedicated with 10 mg.kg-1 ketamine and 0.5 mg.kg-1 diazepam, delivered intramuscularly. After induction using 4.5% sevoflurane introduced through a facemask, the MAD was determined for each animal. The heart rate (HR), respiratory rate (RR), systolic arterial blood pressure (SAP), and cloacal temperature (CT) were recorded before premedication (T0), 15 minutes after premedication (T1), and after MAD determination (T2). Arterial blood gas analyses were performed at T0 and T2. The quality of anaesthesia was evaluated using subjective scales based on animal behaviour and handling during induction, maintenance, and recovery. Statistical analyses were performed using analysis of variance or Kruskal-Wallis tests followed by Tukey's or Dunn's tests.

RESULTS

The minimal anaesthetic doses obtained were 2.4 ± 0.37%, 1.7 ± 0.39%, and 1.3 ± 0.32% for groups S, KS, and KDS, respectively. There were no differences in HR, RR, or CT among groups, but SAP was significantly lower in group S. Sedation was observed in both the premedicated S-KS and S-KDS groups. There were no differences in the quality of intubation and recovery from anaesthesia among the three groups, although the induction time was significantly shorter in the pre-medicated groups, and the KS group showed less muscle relaxation.

CONCLUSIONS

Ketamine alone or the ketamine/diazepam combination decreased the MAD of sevoflurane in parrots (Amazona aestiva). Ketamine alone or in combination with diazepam promoted a good quality of sedation, which improved handling and reduced the stress of the birds. All protocols provided safe anaesthesia in this avian species.

Rapid and reliable sedation induced by diazepam and antagonized by flumazenil in zebra finches (Taeniopygia guttata)

Songbirds have emerged as attractive model systems in many areas of biological research. Notably, songbirds are used in studies of the neurobiological and neuroendocrine mechanisms that shape vocal communication, and zebra finches (Taeniopygia guttata) are the most commonly studied species. In these studies, some form of chemical restraint is often needed to facilitate procedures and to minimize the risk of injury during handling. To determine the minimum dose of the benzodiazepine diazepam that is adequate to achieve deep sedation across individual birds, a low dose (5 mg/kg) and a high dose (10 mg/kg) was administered intramuscularly to 20 zebra finches. Results showed that a 10 mg/kg dose of diazepam resulted in deep sedation, defined by dorsal recumbency, which was achieved in minutes and lasted for several hours. Sedation was induced without complication, because no birds displayed signs of distress during sedation or lethargy after recovery, and was adequate to permit minimally invasive surgical procedures. In addition, the duration of sedation was dose dependent, which provides additional information for researchers who seek to match the depth of sedation to their experimental requirements. Finally, complete recovery from the deeply sedated state was induced by a 0.3 mg/kg dose of the antagonist flumazenil, which enabled birds to more rapidly resume homeostatic behaviors to promote well-being and survival. Together, these results indicate that diazepam is a safe and reliable sedative for use in zebra finches and support specific recommendations to achieve rapid and reliable sedation and recovery.

Bispectral index reveals death-feigning behavior in a red kite (Milvus milvus)

Red kites (Milvus milvus) are birds of prey known to feign death in the presence of humans. An adult wild red kite was anesthetized with isoflurane for coelioscopy. During surgery, heart rate and respiratory rate ranged from 240 to 260 beats per minute and from 16 to 28 breaths rates per minute, respectively. Pupil and corneal reflexes remained present, and body temperature was maintained at 40.4 degrees C (104.7 degrees F). Suppression ratio was 0 during the anesthetic episode. The bispectral index was 44 immediately after intubation, ranged from 44 to 57 during maintenance of anesthesia, and was 59 at the moment of extubation. The index increased to 85 while the kite remained immobile, which was suggestive of feigning death in sternal recumbency. Once the bird was perched upright, it immediately kept the upright position, which confirmed the correspondence of the bispectral index value (85) with a fully conscious patient. Although behavioral or cardiorespiratory variables remained unchanged, the degree of hypnosis was indicated by the bispectral index, which anticipated a possible sudden awakening episode of this bird.

Acute-phase responses vary with pathogen identity in house sparrows (Passer domesticus)

Pathogens may induce different immune responses in hosts contingent on pathogen characteristics, host characteristics, or interactions between the two. We investigated whether the broadly effective acute-phase response (APR), a whole body immune response that occurs in response to constitutive immune receptor activation and includes fever, secretion of immune peptides, and sickness behaviors such as anorexia and lethargy, varies with pathogen identity in the house sparrow ( Passer domesticus ). Birds were challenged with a subcutaneous injection of either a glucan at 0.7 mg/kg (to simulate fungal infection), a synthetic double-stranded RNA at 25 mg/kg (to simulate viral infection), or LPS at 1 mg/kg (to simulate a gram-negative bacterial infection), and then body mass, core body temperature changes, sickness behaviors, and secretion of an acute-phase protein, haptoglobin, were compared. Despite using what are moderate-to-high pyrogen doses for other vertebrates, only house sparrows challenged with LPS showed measurable APRs. Febrile, behavioral, and physiological responses to fungal and viral mimetics had minimal effects.

Cardiorespiratory effects of isoflurane anesthesia in crested caracaras (Caracara plancus)

To evaluate the cardiorespiratory changes induced by isoflurane (ISO) anesthesia in the crested caracara (Caracara plancus), eight crested caracaras that weighed 1.0 kg (range 0.9-1.1 kg) were the subjects for the study. The birds were anesthetized by face mask with ISO for brachial artery catheterization. After recovery, anesthesia was re-induced and maintained with ISO with spontaneous ventilation. Electrocardiography, direct systolic arterial blood pressure (SAP), diastolic arterial blood pressure (DAP), mean arterial blood pressure (MAP), respiratory rate (RR), end-tidal carbon dioxide (P(ET)CO2), and cloacal temperature (T degrees C) were measured before induction (baseline, under physical restraint) and after 5, 10, 15, 20, 25, 30, 35, and 40 min of ISO anesthesia. Arterial blood samples were collected for blood gas analysis at baseline, 10, 25, and 40 min. No cardiac arrhythmias were observed in the present study. RR, SAP, DAP, MAP, T degrees C and pH decreased from baseline values, whereas arterial partial pressures of oxygen and carbon dioxide, bicarbonate concentration, and P(ET)CO2 were significantly higher than baseline. Apnea was not observed in any bird. ISO anesthesia is suitable for use in healthy members of this species despite the moderate cardiovascular and respiratory depression produced.

Some cardiopulmonary effects of sevoflurane in crested caracara (Caracara plancus)

OBJECTIVE

To evaluate the cardiorespiratory changes induced by sevoflurane (SEV) anesthesia in the crested caracara (Caracara plancus).

STUDY DESIGN

Prospective experimental trial.

ANIMALS

Eight crested caracaras (Caracara plancus) weighing 1.0 (0.9-1.1) kg were used for the study.

METHODS

The birds were anesthetized by face mask with isoflurane for brachial artery catheterization. After recovery, anesthesia was re-induced with 6% SEV via face mask. After induction, a noncuffed endotracheal tube was placed and anesthesia was maintained with SEV (3.5% end-tidal) in oxygen (1 L minute(-1)) using an Ayre's T-piece nonrebreathing circuit, with spontaneous ventilation. Electrocardiography (ECG), direct systolic, diastolic and mean arterial blood pressure (SAP, DAP, and MAP), respiratory rate (f(R)), end-tidal carbon dioxide (Pe'CO(2)), and cloacal temperature (T degrees C) were measured before induction (baseline - under physical restraint) and after 5, 10, 15, 20, 25, 30, 35 and 40 minutes of SEV anesthesia. Arterial blood samples were collected for gas analysis at baseline and then at 10, 25 and 40 minutes.

RESULTS

No ventricular arrhythmias were observed in the present study. Respiratory rate, SAP, DAP, MAP, T degrees C and pH decreased from pre-induction values, while arterial partial pressures of oxygen and carbon dioxide, bicarbonate concentration, and Pe'CO(2) were significantly higher than baseline. None of the birds were apneic.

CONCLUSION AND CLINICAL RELEVANCE

Sevoflurane anesthesia is suitable for use in healthy members of this species, despite the moderate cardiovascular and respiratory depression produced.

Pharmacokinetics of intramuscular ketamine in young ostriches premedicated with romifidine

Ketamine is a short-acting dissociative anaesthetic for chemical restraint and surgical anaesthesia in domestic and non-domestic animals. The present study was designed to determine the pharmacokinetics of a single dose of ketamine (10 mg/kg) after intramuscular (i.m.) administration to young ostriches premedicated with romifidine. Ketamine was rapidly absorbed after i.m. administration. Maximal ketamine concentration (C(max)) of 2.93 +/- 0.61 microg/ml was reached at 12.5 +/- 2.50 min and thereafter ketamine concentrations decreased rapidly. The elimination half-life (t(1/2 z)) obtained was 62.37 +/- 17.37 min and mean residence time (MRT) was 77.33 +/- 19.12 min. The area under the curve (AUC) was 114.19 +/- 15.76 microg x min/ml.