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- 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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| 2. |
- 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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| 3. |
- 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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| 8. |
- Essen-Gustavsson, Birgitta
(författare)
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Effect of triheptanoin on muscle metabolism during submaximal exercise in horses
- 2009
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Ingår i: American Journal of Veterinary Research. - : American Veterinary Medical Association (AVMA). - 0002-9645. ; 70, s. 1043-1052
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Tidskriftsartikel (refereegranskat)abstract
- Objective-To compare effects of corn oil or a 7-carbon fat (triheptanoin) on acylcarnitine, lipid, and carbohydrate metabolism in plasma or muscle of exercising horses.Animals-8 Thoroughbred geldings.Procedures-Horses received isocaloric diets containing 650 mL of oil (triheptanoin or corn oil)/d for 18 or 25 days in a crossover design with a 26-day washout period. On day 17 or 24 of each feeding period, the respective oil (217 mL) was nasogastrically administered; 120 minutes later, horses performed a 90-minute submaximal exercise test (SET). Blood and muscle samples were obtained before oil administration and immediately before (blood only), during (blood only), immediately after, and 24 hours after SETs.Results-Compared with values before oil administration, triheptanoin administration increased plasma insulin and C7:0-, C5:0- and C3:0-acylcarnitine concentrations, whereas corn oil administration increased plasma NEFA concentrations. During SETs, plasma C7:0-, C5:0-, and C3:0-acylcarnitine concentrations were higher when triheptanoin, rather than corn oil, was administered to horses. Plasma glucose, NEFA, and C2:0-, C18:1-, and C18:2-acylcarnitine concentrations increased during SETs similarly for both oils. Respiratory quotient and muscle lactate, citrate, malate, glycogen, and ATP concentrations changed similarly from before to after SETs for both oils. Compared with muscle concentrations immediately after SETs, those for glucose-6-phosphate and citrate 24 hours after SETs were lower and for glycogen were similar to values before SETs.Conclusions and Clinical Relevance-Fatigue was not associated with depletion of citric acid cycle intermediates for either oil. Triheptanoin induced a significantly higher insulin secretion and did not appear to enhance muscle glycogen repletion. (Am J Vet Res 2009;70:1043-1052)
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| 9. |
- Grubb, Tamara, et al.
(författare)
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Effects of pulse-delivered inhaled nitric oxide administration on pulmonary perfusion and arterial oxygenation in dorsally recumbent isoflurane-anesthetized horses
- 2014
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Ingår i: American Journal of Veterinary Research. - : American Veterinary Medical Association (AVMA). - 0002-9645. ; 75, s. 949-955
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Tidskriftsartikel (refereegranskat)abstract
- Objective-To image the spatial distribution of pulmonary blood flow by means of scintigraphy, evaluate ventilation-perfusion (V-A/Q) matching and pulmonary blood shunting (Qs/Qt) by means of the multiple inert gas elimination technique (MIGET), and measure arterial oxygenation and plasma endothelin-1 concentrations before, during, and after pulse-delivered inhaled nitric oxide (PiNO) administration to isoflurane-anesthetized horses in dorsal recumbency.Animals-3 healthy adult Standardbreds.Procedures-Nitric oxide was pulsed into the inspired gases in dorsally recumbent isoflurane-anesthetized horses. Assessment of V-A/Q matching, Qs/Qt, and PaO2 content was performed by use of the MIGET, and spatial distribution of pulmonary blood flow was measured by perfusion scintigraphy following IV injection of technetium Tc 99m-labeled macroaggregated human albumin before, during, and 30 minutes after cessation of PiNO administration.Results-During PiNO administration, significant redistribution of blood flow from the dependent regions to the nondependent regions of the lungs was found and was reflected by improvements in V-A/Q matching, decreases in Qs/Qt, and increases in PaO2 content, all of which reverted to baseline values at 30 minutes after PiNO administration.Conclusions and Clinical Relevance-Administration of PiNO in anesthetized dorsally recumbent horses resulted in redistribution of pulmonary blood flow from dependent atelectatic lung regions to nondependent aerated lung regions. Because hypoxemia is commonly the result of atelectasis in anesthetized dorsally recumbent horses, the addition of nitric oxide to inhaled gases could be used clinically to alleviate hypoxemia in horses during anesthesia.
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| 10. |
- Grubb, Tamara L, et al.
(författare)
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Physiologic responses and plasma endothelin-1 concentrations associated with abrupt cessation of nitric oxide inhalation in isoflurane-anesthetized horses
- 2008
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Ingår i: American Journal of Veterinary Research. - : American Veterinary Medical Association (AVMA). - 0002-9645 .- 1943-5681. ; 69:3, s. 423-430
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To assess physiologic responses and plasma endothelin (ET)-1 concentrations associated with abrupt cessation of nitric oxide (NO) inhalation in isoflurane-anesthetized horses. ANIMALS: 6 healthy adult Standardbreds. PROCEDURES: Horses were anesthetized with isoflurane in oxygen and placed in dorsal recumbency. Nitric oxide was pulsed into the respiratory tract for 2.5 hours, and then administration was abruptly discontinued. Just prior to commencement and at cessation of NO administration, and at intervals during a 30-minute period following cessation of NO inhalation, several variables including PaO(2), mean pulmonary artery pressure, venous admixture or pulmonary shunt fraction (Qs/Qt), and plasma ET-1 concentration were recorded or calculated. RESULTS: After cessation of NO inhalation, PaO(2) decreased slowly but significantly (172.7 +/- 29.8 mm Hg to 84.6 +/- 10.9 mm Hg) and Qs/Qt increased slowly but significantly (25 +/- 2% to 40 +/- 3%) over a 30-minute period. Mean pulmonary artery pressure increased slightly (14.0 +/- 1.3 mm Hg to 16.8 +/- 1 mm Hg) over the same time period. No change in serum ET-1 concentration was detected, and other variables did not change or underwent minor changes. CONCLUSIONS AND CLINICAL RELEVANCE: The improvement in arterial oxygenation during pulsed inhalation of NO to healthy isoflurane-anesthetized horses decreased only gradually during a 30-minute period following cessation of NO inhalation, and serum ET-1 concentration was not affected. Because a rapid rebound response did not develop, inhalation of NO might be clinically useful in the treatment of hypoxemia in healthy isoflurane-anesthetized horses.
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