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| 2. |
- Auckburally, Adam, et al.
(författare)
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Development of a method to measure regional perfusion of the lung in anesthetized ponies using computed tomography angiography and the maximum slope model
- 2022
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Ingår i: American Journal of Veterinary Research. - : AMER VETERINARY MEDICAL ASSOC. - 0002-9645 .- 1943-5681. ; 83:2, s. 162-170
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE To develop a method based on CT angiography and the maximum slope model (MSM) to measure regional lung perfusion in anesthetized ponies. ANIMALS 6 ponies. PROCEDURES Anesthetized ponies were positioned in dorsal recumbency in the CT gantry. Contrast was injected, and the lungs were imaged while ponies were breathing spontaneously and while they were mechanically ventilated. Two observers delineated regions of interest in aerated and atelectatic lung, and perfusion in those regions was calculated with the MSM. Measurements obtained with a computerized method were compared with manual measurements, and computerized measurements were compared with previously reported measurements obtained with microspheres. RESULTS Perfusion measurements obtained with the MSM were similar to previously reported values obtained with the microsphere method. While ponies were spontaneously breathing, mean +/- SD perfusion for aerated and atelectatic lung regions were 4.0 +/- 1.9 and 5.0 +/- 1.2 mL/min/g of lung tissue, respectively. During mechanical ventilation, values were 4.6 +/- 1.2 and 2.7 +/- 0.7 mL/min/g of lung tissue at end expiration and 4.1 +/- 0.5 and 2.7 +/- 0.6 mL/min/g of lung tissue at peak inspiration. Intraobserver agreement was acceptable, but interobserver agreement was lower. Computerized measurements compared well with manual measurements.
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| 3. |
- Auckburally, Adam, et al.
(författare)
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Effects of pulsed inhaled nitric oxide delivery on the distribution of pulmonary perfusion in spontaneously breathing and mechanically ventilated anesthetized ponies
- 2022
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Ingår i: American Journal of Veterinary Research. - : American Veterinary Medical Association (AVMA). - 0002-9645 .- 1943-5681. ; 83, s. 171-179
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVETo measure changes in pulmonary perfusion during pulsed inhaled nitric oxide (PiNO) delivery in anesthetized, spontaneously breathing and mechanically ventilated ponies positioned in dorsal recumbency.ANIMALS6 adult ponies.PROCEDURESPonies were anesthetized, positioned in dorsal recumbency in a CT gantry, and allowed to breathe spontaneously. Pulmonary artery, right atrial, and facial artery catheters were placed. Analysis time points were baseline, after 30 minutes of PiNO, and 30 minutes after discontinuation of PiNO. At each time point, iodinated contrast medium was injected, and CT angiography was used to measure pulmonary perfusion. Thermodilution was used to measure cardiac output, and arterial and mixed venous blood samples were collected simultaneously and analyzed. Analyses were repeated while ponies were mechanically ventilated.RESULTSDuring PiNO delivery, perfusion to aerated lung regions increased, perfusion to atelectatic lung regions decreased, arterial partial pressure of oxygen increased, and venous admixture and the alveolar-arterial difference in partial pressure of oxygen decreased. Changes in regional perfusion during PiNO delivery were more pronounced when ponies were spontaneously breathing than when they were mechanically ventilated.CLINICAL RELEVANCEIn anesthetized, dorsally recumbent ponies, PiNO delivery resulted in redistribution of pulmonary perfusion from dependent, atelectatic lung regions to nondependent aerated lung regions, leading to improvements in oxygenation. PiNO may offer a treatment option for impaired oxygenation induced by recumbency.
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| 4. |
- Auckburally, Adam, et al.
(författare)
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Effects of ventilation mode and blood flow on arterial oxygenation during pulse-delivered inhaled nitric oxide in anesthetized horses
- 2019
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Ingår i: American Journal of Veterinary Research. - : American Veterinary Medical Association (AVMA). - 0002-9645. ; 80, s. 275-283
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVETo determine the impact of mechanical ventilation (MV) and perfusion conditions on the efficacy of pulse-delivered inhaled nitric oxide (PiNO) in anesthetized horses.ANIMALS27 healthy adult horses.PROCEDURESAnesthetized horses were allocated into 4 groups: spontaneous breathing (SB) with low (< 70 mm Hg) mean arterial blood pressure (MAP; group SB-L; n = 7), SB with physiologically normal (>= 70 mm Hg) MAP (group SB-N; 8), MV with low MAP (group MV-L; 6), and MV with physiologically normal MAP (group MV-N; 6). Dobutamine was used to maintain MAP > 70 mm Hg. Data were collected after a 60-minute equilibration period and at 15 and 30 minutes during PiNO administration. Variables included Pao(2), arterial oxygen saturation and content, oxygen delivery, and physiologic dead space-to-tidal volume ratio. Data were analyzed with Shapiro-Wilk, Mann-Whitney U, and Friedman ANOVA tests.RESULTSPao(2), arterial oxygen saturation, arterial oxygen content, and oxygen delivery increased significantly with PiNO in the SB-L, SB-N, and MV-N groups; were significantly lower in group MV-L than in group MV-N; and were lower in MV-N than in both SB groups during PiNO. Physiologic dead space-to-tidal volume ratio was highest in the MV-L group.CONCLUSIONS AND CLINICAL RELEVANCEPulmonary perfusion impacted PiNO efficacy during MV but not during SB. Use of PiNO failed to increase oxygenation in the MV-L group, likely because of profound ventilation-perfusion mismatching. During SB, PiNO improved oxygenation irrespective of the magnitude of blood flow, but hypoventilation and hypercarbia persisted. Use of PiNO was most effective in horses with adequate perfusion.
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| 5. |
- Auckburally, Adam, et al.
(författare)
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Review of hypoxaemia in anaesthetized horses: predisposing factors, consequences and management
- 2017
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Ingår i: Veterinary Anaesthesia and Analgesia. - : Elsevier BV. - 1467-2987 .- 1467-2995. ; 44, s. 397-408
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Forskningsöversikt (refereegranskat)abstract
- Objective To discuss how hypoxaemia might be harmful and why horses are particularly predisposed to developing it, to review the strategies that are used to manage hypoxaemia in anaesthetized horses, and to describe how successful these strategies are and the adverse effects associated with them.Databases used Google Scholar and PubMed, using the search terms horse, pony, exercise, anaesthesia, hypoxaemia, oxygen, mortality, morbidity and ventilation perfusion mismatch.Conclusions Although there is no evidence that hypoxaemia is associated with increased morbidity and mortality in anaesthetized horses, most anaesthetists would agree that it is important to recognise and prevent or treat it. Favourable anatomical and physiological adaptations of a horse for exercise adversely affect gas exchange once the animal is recumbent. Hypoxaemia is recognised more frequently in horses than in other domestic species during general anaesthesia, although its incidence in healthy horses remains unreported. Management of hypoxaemia in anaesthetized horses is challenging and often unsuccessful. Positive pressure ventilation strategies to address alveolar atelectasis in humans have been modified for implementation in recumbent anaesthetized horses, but are often accompanied by unpredictable and unacceptable cardiopulmonary adverse effects, and some strategies are difficult or impossible to achieve in adult horses. Furthermore, anticipated beneficial effects of these techniques are inconsistent. Increasing the inspired fraction of oxygen during anaesthesia is often unsuccessful since much of the impairment in gas exchange is a direct result of shunt. Alternative approaches to the problem involve manipulation of pulmonary blood away from atelectatic regions of the lung to better ventilated areas. However, further work is essential, with particular focus on survival associated with general anaesthesia in horses, before any technique can be accepted into widespread clinical use.
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| 6. |
- Bergström, Karin, et al.
(författare)
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Infection prevention and control interventions in the first outbreak of methicillin-resistant Staphylococcus aureus infections in an equine hospital in Sweden
- 2012
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Ingår i: Acta Veterinaria Scandinavica. - : Springer Science and Business Media LLC. - 0044-605X .- 1751-0147. ; 54, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The first outbreak of methicillin-resistant Staphylococcus aureus (MRSA) infection in horses in Sweden occurred in 2008 at the University Animal Hospital and highlighted the need for improved infection prevention and control. The present study describes interventions and infection prevention control in an equine hospital setting July 2008 - April 2010. METHOD: This descriptive study of interventions is based on examination of policy documents, medical records, notes from meetings and cost estimates. MRSA cases were identified through clinical sampling and telephone enquiries about horses post-surgery. Prospective sampling in the hospital environment with culture for MRSA and genotyping of isolates by spa-typing and pulsed-field gel electrophoresis (PFGE) were performed. RESULTS: Interventions focused on interruption of indirect contact spread of MRSA between horses via staff and equipment and included: Temporary suspension of elective surgery; and identification and isolation of MRSA-infected horses; collaboration was initiated between authorities in animal and human public health, human medicine infection control and the veterinary hospital; extensive cleaning and disinfection was performed; basic hygiene and cleaning policies, staff training, equipment modification and interior renovation were implemented over seven months.Ten (11%) of 92 surfaces sampled between July 2008 and April 2010 tested positive for MRSA spa-type 011, seven of which were from the first of nine sampling occasions. PFGE typing showed the isolates to be the outbreak strain (9 of 10) or a closely related strain. Two new cases of MRSA infection occurred 14 and 19 months later, but had no proven connections to the outbreak cases. CONCLUSIONS: Collaboration between relevant authorities and the veterinary hospital and formation of an infection control committee with an executive working group were required to move the intervention process forward. Support from hospital management and the dedication of staff were essential for the development and implementation of new, improved routines. Demonstration of the outbreak strain in the environment was useful for interventions such as improvement of cleaning routines and interior design, and increased compliance with basic hygienic precautions. The interventions led to a reduction in MRSA-positive samples and the outbreak was considered curbed as no new cases occurred for over a year.
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| 7. |
- Edner, Anna H., et al.
(författare)
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Metabolism before, during and after anaesthesia in colic and healthy horses
- 2007
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Ingår i: Acta Veterinaria Scandinavica. - : Springer Science and Business Media LLC. - 0044-605X .- 1751-0147. ; 49:1, s. 34-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Many colic horses are compromised due to the disease state and from hours of starvation and sometimes long trailer rides. This could influence their muscle energy reserves and affect the horses' ability to recover. The principal aim was to follow metabolic parameter before, during, and up to 7 days after anaesthesia in healthy horses and in horses undergoing abdominal surgery due to colic. Methods: 20 healthy horses given anaesthesia alone and 20 colic horses subjected to emergency abdominal surgery were anaesthetised for a mean of 228 minutes and 183 minutes respectively. Blood for analysis of haematology, electrolytes, cortisol, creatine kinase (CK), free fatty acids (FFA), glycerol, glucose and lactate was sampled before, during, and up to 7 days after anaesthesia. Arterial and venous blood gases were obtained before, during and up to 8 hours after recovery. Gluteal muscle biopsy specimens for biochemical analysis of muscle metabolites were obtained at start and end of anaesthesia and 1 h and 1 day after recovery. Results: Plasma cortisol, FFA, glycerol, glucose, lactate and CK were elevated and serum phosphate and potassium were lower in colic horses before anaesthesia. Muscle adenosine triphosphate (ATP) content was low in several colic horses. Anaesthesia and surgery resulted in a decrease in plasma FFA and glycerol in colic horses whereas levels increased in healthy horses. During anaesthesia muscle and plasma lactate and plasma phosphate increased in both groups. In the colic horses plasma lactate increased further after recovery. Plasma FFA and glycerol increased 8 h after standing in the colic horses. In both groups, plasma concentrations of CK increased and serum phosphate decreased post-anaesthesia. On Day 7 most parameters were not different between groups. Colic horses lost on average 8% of their initial weight. Eleven colic horses completed the study. Conclusion: Colic horses entered anaesthesia with altered metabolism and in a negative oxygen balance. Muscle oxygenation was insufficient during anaesthesia in both groups, although to a lesser extent in the healthy horses. The post-anaesthetic period was associated with increased lipolysis and weight loss in the colic horses, indicating a negative energy balance during the first week post-operatively.
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| 8. |
- Edner, Anna, et al.
(författare)
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Metabolism during anaesthesia and recovery in colic and healthy horses : a microdialysis study
- 2009
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Ingår i: Acta Veterinaria Scandinavica. - : Springer Science and Business Media LLC. - 0044-605X .- 1751-0147. ; 51:1, s. 10-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Muscle metabolism in horses has been studied mainly by analysis of substances in blood or plasma and muscle biopsy specimens. By using microdialysis, real-time monitoring of the metabolic events in local tissue with a minimum of trauma is possible. There is limited information about muscle metabolism in the early recovery period after anaesthesia in horses and especially in the colic horse. The aims were to evaluate the microdialysis technique as a complement to plasma analysis and to study the concentration changes in lactate, pyruvate, glucose, glycerol, and urea during anaesthesia and in the recovery period in colic horses undergoing abdominal surgery and in healthy horses not subjected to surgery. Methods: Ten healthy university-owned horses given anaesthesia alone and ten client-owned colic horses subjected to emergency abdominal surgery were anaesthetised for a mean (range) of 230 min (193-273) and 208 min (145-300) respectively. Venous blood samples were taken before anaesthesia. Venous blood sampling and microdialysis in the gluteal muscle were performed during anaesthesia and until 24 h after anaesthesia. Temporal changes and differences between groups were analysed with an ANOVA for repeated measures followed by Tukey Post Hoc test or Planned Comparisons. Results: Lactate, glucose and urea, in both dialysate and plasma, were higher in the colic horses than in the healthy horses for several hours after recovery to standing. In the colic horses, lactate, glucose, and urea in dialysate, and lactate in plasma increased during the attempts to stand. The lactate-to-pyruvate ratio was initially high in sampled colic horses but decreased over time. In the colic horses, dialysate glycerol concentrations varied considerably whereas in the healthy horses, dialysate glycerol was elevated during anaesthesia but decreased after standing. In both groups, lactate concentration was higher in dialysate than in plasma. The correspondence between dialysate and plasma concentrations of glucose, urea and glycerol varied. Conclusion: Microdialysis proved to be suitable in the clinical setting for monitoring of the metabolic events during anaesthesia and recovery. It was possible with this technique to show greater muscle metabolic alterations in the colic horses compared to the healthy horses in response to regaining the standing position.
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| 9. |
- Fahlman, Åsa, et al.
(författare)
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Oxygen supplementation in anesthetized brown bears (Ursus arctos) - how low can you go?
- 2014
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Ingår i: Journal of Wildlife Diseases. - : Wildlife Disease Association. - 0090-3558 .- 1943-3700. ; 50, s. 574-581
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Tidskriftsartikel (refereegranskat)abstract
- Hypoxemia is anticipated during wildlife anesthesia and thus should be prevented. We evaluated the efficacy of low flow rates of supplemental oxygen for improvement of arterial oxygenation in anesthetized brown bears (Ursus arctos). The study included 32 free-ranging brown bears (yearlings, subadults, and adults; body mass 12-250 kg) that were darted with medetomidine-zolazepam-tiletamine (MZT) from a helicopter in Sweden. During anesthesia, oxygen was administered intranasally from portable oxygen cylinders at different flow rates (0.5-3 L/min). Arterial blood samples were collected before (pre-O-2), during, and after oxygen therapy and immediately processed with a portable analyzer. Rectal temperature, respiratory rate, heart rate, and pulse oximetry-derived hemoglobin oxygen saturation were recorded. Intranasal oxygen supplementation at the evaluated flow rates significantly increased the partial pressure of arterial oxygen (PaO2) from pre-O-2 values of 9.1 +/- 1.3 (6.3-10.9) kPa to 20.4 +/- 6.8 (11.1-38.7) kPa during oxygen therapy. When oxygen therapy was discontinued, the PaO2 decreased to values not significantly different from the pre-O-2, values. In relation to the body mass of the bears, the following oxygen flow rates are recommended: 0.5 L/min to bears <51 kg, 1 L/min to bears 51-100 kg, 2 L/min to bears 101-200 kg, and 3 L/min to bears 201-250 kg. In conclusion, low flow rates of intranasal oxygen were sufficient to improve arterial oxygenation in brown bears anesthetized with MZT. Because hypoxemia quickly recurred when oxygen was discontinued, oxygen supplementation should be provided continuously throughout anesthesia.
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| 10. |
- Fahlman, Åsa, et al.
(författare)
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Physiologic Evaluation of Capture and Anesthesia with Medetomidine–Zolazepam–Tiletamine in Brown Bears (Ursus arctos)
- 2011
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Ingår i: Journal of Zoo and Wildlife Medicine. - : American Association of Zoo Veterinarians. - 1042-7260 .- 1937-2825. ; 42, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- Physiologic variables during anesthesia with medetomidine-zolazepam-tiletamine were evaluated in 52 free-ranging brown bears (Ursus arctos) darted from a helicopter and in six captive brown bears darted at a zoo. During anesthesia, rectal temperature, respiratory rate, heart rate, and pulse oximetry derived hemoglobin oxygen saturation were recorded. Arterial blood samples were collected and immediately analyzed for evaluation of pulmonary gas exchange, acid base status, and selected hematologic and plasma variables. At the end of anesthesia, atipamezole was administered intramuscularly at five times the medetomidine dose. Capture-induced hyperthermia and lactic acidemia were documented in free-ranging bears. Hypoxemia during anesthesia was documented in both free-ranging and captive bears. In free-ranging bears, rectal temperature, heart rate, lactate, hematocrit, and hemoglobin decreased significantly during anesthesia, whereas partial pressure of arterial carbon dioxide, pH, potassium, and glucose increased. Yearlings had a significantly higher heart rate, pH, base excess, bicarbonate, and glucose, and had a significantly lower rectal temperature, sodium, hematocrit, and hemoglobin when compared with subadult and adult brown bears. In conclusion, alterations in pulmonary gas exchange and acid base status in brown bears during anesthesia with medetomidine zolazepam tiletamine with the doses and capture methods used in this study were identified. Oxygen supplementation is recommended to counteract hypoxemia during anesthesia.
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