Changes in the hematobiochemical, acid-base and blood gas elements as well as biomarkers of inflammation and bone metabolism in donkeys (Equus asinus) with acute bleeding.

Background: Acute hemorrhage is fatal in equines with a complication of severe hypovolemic shock that causes a sudden death in such cases. Aim: This study was designed to report the influences of acute bleeding in conscious non-sedated donkeys (Equus asinus) on the hematobiochemical variables, acid-base, blood gas elements, and markers of inflammation and bone metabolism. Methods: Eight healthy donkeys were used where a total of 900 ml of whole blood was collected. Five blood samples were collected from each animal: just before collection of blood (T0); (2) 30 (T1), 60 (T2), 120 (T3), and 240 minutes (T4) later. The blood panels including total white blood cells, lymphocytes, neutrophils, red blood cell counts (RBCs), HCT, hemoglobin (Hg), and RBCs indices were measured. Biochemical parameters and electrolytes were evaluated. The activity of aspartate aminotransferase (AST), creatine kinase (CK), and γ-glutamyl transferase (GGT) were also determined. Complete acid-base and blood gas panels were assessed. Serum amyloid A (SAA), haptoglobin (Hp), osteocalcin (OC), bone alkaline phosphatase (b-ALP), and pyridinoline cross-links (PYD) were measured. Results: The RBCs, Hg, and HCT increased significantly at points T1, T2, and T3 compared to T0. The concentrations of total proteins and albumin decreased significantly at points T3 and T4. The blood urea nitrogen concentrations increased significantly at T4. Creatinine concentrations increased significantly at T2 and T3. The AST, GGT, and CK decreased significantly. On the other hand, glucose increased significantly at T3 and T4. The pH decreased significantly at points T1, T2, T3, and T4. The PCO2 increased significantly at T3 and T4. The BE, HCO3, and TCO2 values decreased significantly at T2, T3, and T4. Contrary, the AG increased significantly at points T3 and T4. The potassium increased significantly at T1-T4 and chloride decreased significantly at T3 and T4. Lactate showed significant increases at T1-T4. The SAA, Hp, OC, b-ALP, and PYD did not differ significantly at T1-T4. Conclusion: In conscious non-sedated donkeys, induced bleeding resulted in significant changes in the hematobiochemical elements, the acid-base status, and blood gas and electrolyte parameters. However, it did not change the markers of inflammation and bone metabolism.

Spurious hyperbicarbonatemia and a negative anion gap in a cat and a dog with severe rhabdomyolysis.

A 3-year-old male neutered domestic shorthair cat and a 2-year-old male neutered Labrador-mix dog were separately presented to the Veterinary Medical Center for evaluation after sustaining significant muscle trauma due to a dog attack and seizure activity, respectively. In both cases, biochemical analysis was consistent with rhabdomyolysis. Additionally, a markedly increased measured serum bicarbonate concentration and negative calculated anion gap were observed. As these biochemical abnormalities were not expected and deemed incompatible with life, an interference with the analyzer measurement of bicarbonate involving marked increases in pyruvate and lactate dehydrogenase (LDH) following myocyte injury was suspected. Venous blood gas analysis calculated bicarbonate concentration and anion gap were within reference interval, while measured LDH activity was markedly increased. These findings supported an analyzer-generated interference. This is the first published report of a previously described chemistry analyzer interference of markedly increased LDH activity with serum bicarbonate concentration measurement in dogs and cats. Awareness of this interference is important, particularly in the emergency setting, as it may influence case management.

Effect of continuous positive airway pressure helmet on respiratory function following surgical procedures in brachycephalic dogs: A randomized controlled trial.

OBJECTIVE: To evaluate the effect of continuous positive airway pressure (CPAP) on respiratory function in the early postoperative period of brachycephalic dogs. STUDY DESIGN: Prospective, randomized clinical trial. ANIMALS: A total of 32 dogs. METHODS: Dogs were assigned to recover with or without CPAP (control) and assessed at specific time points over 1 h. Treatment was discontinued for dogs with a CPAP tolerance score of 3 or more (from a range of 0-4). The primary outcome was pulse oximetry (SpO2). Secondary outcomes were arterial O2 pressure (PaO2)/FiO2 ratio (PaO2/FiO2), arterial CO2 pressure (PaCO2), and rectal temperature. For dogs that reached a CPAP tolerance score of 3 or more, only the data collected up to the time point before discontinuation were included in the analysis. The treatment effect (ß) was analyzed using random effects models and the results were reported with 95% confidence intervals. RESULTS: Dogs were assigned randomly to each protocol. Baseline characteristics in both groups were comparable. Arterial blood gases were obtained in seven control group dogs and nine CPAP group dogs. Treatment did not affect SpO2 (ß = -0.1, -2.1 to 2.0) but affected the PaO2/FiO2 ratio (ß = 58.1, 2.6 to 113.6), with no effects on PaCO2 (ß = -4.3, -10.5 to 1.9) or temperature (ß = 0.4, -0.8 to 1.6). CONCLUSION: In postoperative brachycephalic dogs, CPAP had no effect on SpO2 but improved the PaO2/FiO2 ratio in brachycephalic dogs postoperatively. CLINICAL SIGNIFICANCE: Continuous positive airway pressure offers a valuable solution to improve gas exchange efficiency, a prevalent concern in postoperative brachycephalic dogs, with the potential to enhance overall outcomes.

Minimum anesthetic concentration of isoflurane and sevoflurane and cardiorespiratory effects of varying inspired oxygen fractions in Magellanic penguins (Spheniscus magellanicus).

The aim of this study was to determine the minimum anesthetic concentration of isoflurane (MACISO) and sevoflurane (MACSEVO) and evaluate the cardiorespiratory changes induced by varying fractions of inspired oxygen (FiO2) in Magellanic penguins (Spheniscus magellanicus). Twenty adult penguins (3.53 ± 0.44 kg) of undetermined sex were used. Both MACISO (n = 9) and MACSEVO (n = 13) were established using an up-and-down design. Next, twelve mechanically ventilated penguins were maintained at 1 MACISO or 1 MACSEVO (n = 6 per group) with the FiO2 initially set at 1.0. Three FiO2 values (0.6, 0.4 and 0.2) were then held constant during anesthesia for 20 minutes each. Arterial blood samples were collected for gas analysis after the 20-minute period for each FiO2. Mean ± SD MACISO was 1.93 ± 0.10% and MACSEVO was 3.53 ± 0.13%. Other than heart rate at 0.6 FiO2 (86 ± 11 beats/minute in MACISO and 132 ± 37 beats/minute in MACSEVO; p = 0.041), no significant cardiorespiratory differences were detected between groups. In both groups, decreasing the FiO2 produced increased pH values and reduced partial pressures of carbon dioxide and bicarbonate. Partial pressures of oxygen (PaO2) gradually lowered from 1.0 FiO2 through 0.2 FiO2, though hypoxemia (PaO2 < 80 mmHg) occurred only with the latter FiO2. The MACISO and the MACSEVO for the Magellanic penguin fell within the upper range of reported avian MAC estimates. To prevent hypoxemia in healthy, mechanically ventilated, either isoflurane- or sevoflurane-anesthetized Magellanic penguins, a minimum FiO2 of 0.4 should be used.

Blood gases, acid-base, and metabolic alterations in calves with bronchopneumonia diagnosed via clinical signs and thoracic ultrasonography: A cross-sectional study.

BACKGROUND: Bronchopneumonia (BP) in calves potentially causes systemic changes. OBJECTIVES: To describe metabolic, arterial blood gas, and acid-base disorders in calves with BP diagnosed by thoracic ultrasound (TUS), Wisconsin score (WISC), and combinations of WISC and TUS. ANIMALS: Two hundred thirty-one dairy preweaned dairy calves from 13 dairy farms. METHODS: Cross-sectional study. Each calf sequentially underwent arterial blood gas evaluation, WISC score, venous sampling, and TUS. Calves were grouped based on a single diagnostic method and combination of WISC and 2 TUS cutoffs (≥1 cm; ≥3 cm) as healthy, upper respiratory tract infection, subclinical BP, and clinical BP. RESULTS: Oxygenation and acid-base variables were unaffected. Glucose concentration in TUS-affected calves was significantly lower (P < .001) than in healthy calves (median ≥TUS1cm = 5.2 mmol/L 25%-75% interquartile range [IQR] 4.5-6.1,

Arterial blood gas measurements are different for brachycephalic and nonbrachycephalic dogs acclimatized to an altitude of 1,535 meters.

OBJECTIVE: To define reference intervals (RIs) for arterial blood gas (aBG) measurements in healthy, nonsedated, dolichocephalic, and mesocephalic (nonbrachycephalic) dogs at approximately 1,535 m above sea level and compare these findings with healthy, nonsedated, brachycephalic dogs living at the same altitude. ANIMALS: 120 adult nonbrachycephalic dogs and 20 adult brachycephalic dogs. METHODS: Cases were prospectively enrolled from October 2021 to June 2022. Dogs were enrolled from the community or after presentation for wellness examinations or minor injuries including lacerations, nail injuries, and lameness. Physical examinations and systolic blood pressure (sBP) measurements were obtained before blood sample collection. Arterial blood was collected from the dorsal pedal artery or femoral artery. After data collection, brachycephalic dogs underwent pre- and postexercise tolerance assessments. RESULTS: The mean and RI values for arterial pH (7.442; 7.375 to 7.515), partial pressure of oxygen in arterial blood (Pao2; 78.3; 59.2 to 92.7 mm Hg), partial pressure of carbon dioxide in arterial blood (Paco2; 28.0; 21.5 to 34.4 mm Hg), saturation of arterial oxygen (Sao2; 98.4; 84.3% to 101.4%), HCO3 (18.9; 14.9 to 22.4 mmol/L), concentration of total hemoglobin (ctHb; 17.5; 13.4 to 21.1 g/dL), and sBP (133; 94 to 180 mm Hg) were established for healthy nonbrachycephalic dogs at 1,535-m altitude. All aBG measurements were statistically and clinically different from those previously reported for dogs at sea level. Brachycephalic dogs had significantly lower Pao2 and Sao2 (P = .0150 and P = .0237, respectively) and significantly higher ctHb (P = .0396) compared to nonbrachycephalic dogs acclimatized to the same altitude; the nonbrachycephalic RIs were not transferable to the brachycephalic dogs for Pao2. CLINICAL RELEVANCE: This study represents the first collation of aBG measurements for healthy nonbrachycephalic dogs acclimatized to an altitude of 1,535 m. Additionally, this study identified differences in arterial oxygenation measurements between brachycephalic and nonbrachycephalic dogs. RIs in brachycephalic dogs need to be established.

Investigation of the association between oxygen reserve index and arterial partial oxygen pressure in anesthetized dogs.

OBJECTIVE: To evaluate the relationship between oxygen reserve index (ORI) and arterial partial pressure of oxygen (PaO2) in anesthetized dogs. STUDY DESIGN: Prospective experimental study. ANIMALS: A total of eight healthy adult Beagle dogs with a median age of 38 (range 20-87) months and a median body mass of 8.6 (range 7.0-13.8) kg. METHODS: After induction of general anesthesia with propofol, dogs were mechanically ventilated and anesthesia maintained with isoflurane carried in oxygen. Arterial blood samples were collected from a catheter placed in the femoral artery. ORI was measured by placing a CO-oximeter sensor on the tongue. Inspired oxygen fraction (FiO2) was increased from 21% to > 95% in increments of 5%. PaO2 and ORI were recorded and compared at different times. The relationship between ORI and PaO2 was investigated using a nonlinear function, the Hill equation, and a linear regression analysis was performed, as appropriate. RESULTS: A total of 128 pairs of values were compared for all dogs. Applying the Hill equation to the relationship between ORI and PaO2 resulted in R2 = 0.80 (p < 0.001) with a Hill coefficient of 3.7. It was predicted that ORI ranged 0.1-0.9 as PaO2 ranged 127.0-417.9 mmHg and that in the more linear portion of the range, PaO2 of 127.0-289.9 mmHg ORI ranged 0.1-0.7. Linear regression analysis in the more linear portion showed a weak correlation (R2 = 0.29, p = 0.006). CONCLUSIONS AND CLINICAL RELEVANCE: In the present study, the Hill equation predicted the relationship between PaO2 and ORI for PaO2 ranging 127.0-417.9 mmHg in anesthetized dogs. However, in the linear portion of the PaO2, the coefficient of determination was low, indicating that ORI is not a surrogate for PaO2.

Non-invasive assessment of oxygenation status using the oxygen reserve index in dogs.

BACKGROUND: The oxygen reserve index (ORi) is a real-time, continuous index measured with multi-wavelength pulse CO-oximetry technology. It estimates mild hyperoxemia in humans, which is defined as a partial pressure of oxygen (PaO2) level between 100 and 200 mmHg. The objectives of this study were to assess the correlation between ORi and PaO2, as well as to determine its ability in detecting mild hyperoxemia in dogs. METHODS: This prospective observational study enrolled 37 anaesthetised and mechanically ventilated dogs undergoing elective procedures. Simultaneous measurements of ORi and PaO2 were collected, using a multi-wavelength pulse CO-oximeter with a probe placed on the dog's tongue, and a blood gas analyser, respectively. A mixed-effects model was used to calculate the correlation (r2) between simultaneous measurements of ORi and PaO2. The trending ability of ORi to identify dependable and proportional changes of PaO2 was determined. The diagnostic performances of ORi to detect PaO2 ≥ 150 mmHg and ≥ 190 mmHg were estimated using the area under the receiver operating characteristic curve (AUROC). The effects of perfusion index (PI), haemoglobin (Hb), arterial blood pH and partial pressure of carbon dioxide (PaCO2) on AUROC for PaO2 ≥ 150 mmHg were evaluated. RESULTS: A total of 101 paired measurements of ORi and PaO2 were collected. PaO2 values ranged from 74 to 258 mmHg. A strong positive correlation (r2 = 0.52, p < 0.001) was found between ORi and PaO2. The trending ability ORi was 90.7%, with 92% sensitivity and 89% specificity in detecting decreasing PaO2. An ORi value ≥ 0.53 and ≥ 0.76 indicated a PaO2 ≥ 150 and ≥ 190 mmHg, respectively, with ≥ 82% sensitivity, ≥ 77% specificity and AUROC ≥ 0.75. The AUROC of ORi was not affected by PI, Hb, pH and PaCO2. CONCLUSIONS: In anaesthetised dogs, ORi may detect mild hyperoxaemia, although it does not replace blood gas analysis for measuring the arterial partial pressure of oxygen. ORi monitoring could be used to non-invasively assess oxygenation in dogs receiving supplemental oxygen, limiting excessive hyperoxia.

Agreement between hematocrit values determined by the Cobas b121 blood gas analyzer and the microhematocrit method in dogs, cats, and horses.

BACKGROUND: Packed cell volume (PCV) is important for assessing a patient's health status. Some blood gas analyzers measure hematocrit, and the agreement with PCV varies among different analyzers. OBJECTIVES: We aimed to determine the agreement between PCV measured by microcentrifugation and hematocrit measured by the Cobas b121 blood gas analyzer in dogs, cats, and horses. METHODS: Whole blood samples for PCV and blood gas analysis were collected in lithium-heparin syringes and analyzed within 10 min of collection. Agreement and association between the PCV and Cobas b121 generated hematocrit were assessed by the Bland-Altman method, Pearson's correlation, Deming regression analysis, and paired t tests. A total allowable error of 10% was used for the analysis. RESULTS: This study included 45 dogs, 45 cats, and 33 horses. The respective mean ± SD (minimum-maximum) of PCVs and hematocrits were: dogs, 34.9 ± 9.9% (9.0-55.0) and 32.5 ± 8.8% (10.4-50.6); cats, 29.0 ± 9.6% (11.0-51.0) and 26.9 ± 9.3% (10.2-50.9); horses, 34.2 ± 6.5% (24.0-47.0) and 34.1 ± 6.0% (22.5-46.1). There were no significant differences between the methods. The bias ± SD was: dogs, -2.4 ± 2.6%; cats, -2.2 ± 2.3%; horses, -0.1 ± 2.4%. Pearson's correlation coefficients were > 0.90 for all species (P < 0.0001). In 60%, 49%, and 85% of the samples for dogs, cats, and horses, respectively, the percentage differences between the methods were within 10%. CONCLUSIONS: The Cobas b121 blood gas analyzer provided accurate estimates of PCVs in horses. However, in dogs and cats, there was a large frequency of unacceptable differences between the methods.

Evaluation and establishment of reference intervals using the i-STAT1 blood chemistry analyzer in turkeys.

In veterinary medicine, point-of-care testing techniques have become popular, since they provide immediate results and only small amounts of blood are needed. The handheld i-STAT1 blood analyzer is used by poultry researchers and veterinarians; however, no studies have evaluated the accuracy of this analyzer determined reference intervals in turkey blood. The objectives of this study were to 1) investigate the effect of storage time on turkey blood analytes, 2) compare the results obtained by the i-STAT1 analyzer to those obtained by the GEM Premier 3000, a conventional laboratory analyzer, and 3) establish reference intervals for blood gases and chemistry analytes in growing turkeys using the i-Stat. For the first and second objectives, we used the CG8+ i-STAT1 cartridges to test blood from 30 healthy turkeys in triplicate and once with the conventional analyzer. To establish the reference intervals, we tested a total 330 blood samples from healthy turkeys from 6 independent flocks during a 3-yr period. Blood samples were then divided into brooder (<1 wk) and growing (1-12 wk of age). Friedman's test demonstrated significant time-dependent changes in blood gas analytes, but not for electrolytes. Bland-Altman analysis revealed that there was agreement between the i-STAT1 and the GEM Premier 300 for most of the analytes. However, Passing-Bablok regression analysis identified constant and proportional biases in the measurement of multiple analytes. Tukey's test revealed significant differences in the whole blood analytes between the means of brooding and growing birds. The data presented in the present study provide a basis for measuring and interpreting blood analytes in the brooding and growing stages of the turkey lifecycle, offering a new approach to health monitoring in growing turkeys.

Cephalic and saphenous venous blood collected by continuous heating of the paws compared with arterial blood for measurement of blood gas values in well-perfused dogs.

BACKGROUND: "Arterialization" of the dorsal hand vein is well-established in human medicine, but not in veterinary medicine. OBJECTIVES: To compare cephalic and saphenous venous blood collected by continuously heating the paws to 37°C ("arterialization"), with arterial blood (AB) for measurement of blood gas variables in well-perfused dogs. ANIMALS: Eight healthy dogs. METHODS: Experimental study. Fore and hind paws were continuously heated to 37°C to "arterialize" cephalic and saphenous venous blood. AB and "arterialized" cephalic and saphenous venous blood (ACV and ASV, respectively) were simultaneously collected from lightly anesthetized dogs with induced metabolic and respiratory acid-base disorders. The pH, partial pressures of carbon dioxide (PCO2 ) and oxygen (PO2 ), bicarbonate concentration [HCO3 - ], and base excess (BE) were measured once in each state. Systolic blood pressure was maintained above 100 mm Hg. The AB, ACV, and ASV values were compared. RESULTS: The pH, [HCO3 - ], and BE values had no significant difference and good agreement, the PCO2 values had a strong correlation (correlation coefficient of .91-1.00), and the PO2 values had a significant difference (P < .01) and poor agreement between AB and ACV, and between AB and ASV. The PCO2 values of ASV overestimated those of AB by ~3.0 mm Hg, which was considered within clinically allowable limits, while those of ACV were not within clinically allowable limits. CONCLUSIONS AND CLINICAL IMPORTANCE: Under experimental conditions, the ASV samples were more identical to the AB samples than the ACV samples for pH, PCO2 , [HCO3 - ], and BE values in well-perfused dogs. The saphenous vein is suitable for "arterialization."

A randomized controlled trial investigating the effect of transport duration and age at transport on surplus dairy calves: Part II. Impact on hematological variables.

Surplus dairy calves often arrive at veal and dairy-beef rearing facilities with health and blood metabolite level abnormalities, which can affect their welfare and performance, predisposing them to future health challenges. The objective of this randomized controlled trial was to investigate the effects of transport duration and age at the time of transport on blood parameters in surplus dairy calves following 6, 12, or 16 h of continuous road transportation. All surplus calves from 5 commercial dairy farms in Ontario were enrolled and examined daily before transport (n = 175). On the day of transportation, calves were weighed, blood sampled, and randomly assigned to 6, 12, or 16 h of transportation. Blood samples were then collected immediately after transportation, as well as 24, 48, and 72 h thereafter. Serum was analyzed at a provincial diagnostic laboratory for nonesterified fatty acids (NEFA), ß-hydroxybutyric acid (BHBA), creatine kinase (CK), cholesterol, and haptoglobin. In addition, blood gas and electrolyte values were also assessed at the time of sample collection. Mixed models with repeated measures were used to assess the effects of transport duration, breed, sex, transfer of passive immunity status, weight before transportation, and age at transportation on blood parameters. Immediately following transportation, NEFA and BHBA were greater for calves transported for 12 h (Δ = 0.22 mmol/L NEFA, 95% CI = 0.15 to 0.30; Δ = 0.04 mmol/L BHBA, 95% CI = 0.02 to 0.06) and 16 h (Δ = 0.35 mmol/L NEFA, 95% CI = 0.27 to 0.42; Δ = 0.10 mmol/L BHBA, 95% CI = 0.08 to 0.11) compared with calves transported for 6 h. Glucose was lower immediately following transportation in calves transported for 16 h compared with 6 h (Δ = -15.54 mg/dL, 95% CI = -21.54 to -9.54). In addition, pH and HCO3- were lower in calves transported for 12 (Δ = -0.09 pH, 95% CI = -0.13 to -0.05; Δ = -1.59 mmol/L HCO3-, 95% CI = -2.61 to -0.56) and 16 h (Δ = -0.07 pH, 95% CI = -0.12 to -0.03; Δ = -1.95 mmol/L HCO3-, 95% CI = -2.95 to -0.95) compared with calves transported for 6 h. Calves transported between 15 and 19 d of age had a higher concentration of cholesterol and CK (Δ = 0.27 mmol/L cholesterol; 37.18 U/L CK) compared with 2- to 6-d-old calves, and calves 12 to 14 d old had greater reduction in HCO3- (Δ = -0.92 mmol/L) compared with 2- to 6-d-old calves. These findings show that transporting calves for long distances results in lower glucose concentration and suboptimal energy status, and that this effect varies based on the calf's age.

Evaluation of Nasal Oxygen Administration at Various Flow Rates and Concentrations in Conscious, Standing Adult Horses.

This study evaluated the effects of various flow rates and fractions of oxygen on arterial blood gas parameters and on the fraction of inspired oxygen (FIO2) delivered to the distal trachea. Oxygen was administered to 6 healthy, conscious, standing, adult horses via single nasal cannula positioned within the nasopharynx. Three flow rates (5, 15, 30 L/min) and fractions of oxygen (21, 50, 100%) were delivered for 15 minutes, each in a randomized order. FIO2 was measured at the level of the nares and distal trachea. Adverse reactions were not observed with any flow rate. FIO2 (nares and trachea) and PaO2 increased with increasing flow rate and fraction of oxygen (P < .0001). FIO2 (trachea) was significantly less than FIO2 (nares) at 50% and 100% oxygen at all flow rates (P < .0001). Differences in PaO2 were not observed between 100% oxygen-5L/min and 50% oxygen-15L/min and or between 100% oxygen-15L/min and 50% oxygen-30L/min. Tracheal FIO2 for 100% oxygen-15L/min was increased compared to 50% oxygen-30L/min (P < .0001). Respiratory rate, ETCO2, PaCO2, and pH did not differ between treatments. Administration of 50% oxygen via nasal cannula at 15 and 30 L/min effectively increased in PaO2 and was well tolerated in conscious, standing, healthy horses. While these results can be used guide therapy in hypoxemic horses, evaluation of the administration of 50% oxygen to horses with respiratory disease is warranted.

Does postprandial lipemia interfere with blood gas analysis and assessment of acid-base status in dogs?

To evaluate the interference of postprandial lipemia on blood gas parameters and to assess the acid-base status by the quantitative approach of the strong ion model blood samples of 15 healthy dogs were collected during fasting (0 h) and at one (1 h), three (3 h) and five (5 h) hours after the induction of lipemia with a hypercaloric diet. Total cholesterol (TC) and triglyceride (TG) levels were used to assess lipemia and these were correlated with the parameters evaluated accordingly. Anion gap decreased at 5 h without correlation with TC and TG, whereas other parameters measured by the blood gasometer did not change. In the evaluation of the acid base state, the apparent strong ion difference (SIDa) and the strong ion gap (SIG) showed a decrease at 5 h without correlation with lipemia. Lipid levels correlated with the effective strong ion difference (SIDe), the concentration of total non-volatile weak acids (Atot), albumin, phosphate, and magnesium. The SIDe increased at 1 h and at 3 h; the Atot at 1 h, 3 h, and 5 h; albumin increased at 1 h and 3 h; phosphate increased at 1 h, 3 h and 5 h; and magnesium decreased at 5 h. Though postprandial lipemia does not interfere with blood gas analysis, it can cause errors in the variables used to assess the acid-base status, which are dependent on biochemical analytes. Therefore, caution is required when interpreting electrolyte disturbances that result from the postprandial state.

Preliminary study evaluating the assessment of changes in pulmonary function associated with body positioning in dogs with suspected aspiration pneumonia.

OBJECTIVE: To evaluate the variability in arterial blood gas (ABG) assessment of pulmonary function with different body positioning in dogs with suspected aspiration pneumonia. KEY FINDINGS: The median differences in alveolar-arterial gradient, Pao2 , and Paco2 values in different recumbencies were not statistically significantly different, both within patients and across the study population. No difference was noted in ABG values in the subgroups with unilateral or bilateral disease or that were more affected on the right side versus the left side. SIGNIFICANCE: This preliminary study provides data that can be used to calculate appropriate sample sizes for subsequent studies investigating the impact of recumbency on pulmonary function in patients with aspiration pneumonia.

Effects of time delay and blood storage methods on analysis of canine venous blood samples with an Element point-of-care analyzer.

BACKGROUND: Manufacturers of point-of-care (POC) analyzers recommend immediate processing and anaerobic collection of blood samples. However, it is not uncommon for clinical scenarios to result in delayed sample processing or room air exposure that could impact the test results. OBJECTIVE: To investigate the effect of time delay and sample storage method on key POC analytes in canine venous blood samples processed with an Element POC analyzer. METHODS: Blood gas analysis was performed on venous blood samples at times 0 (T0), 15, 30, and 60 minutes after sampling using three different storage methods: preheparinized plastic syringes and two different lithium heparin tubes. To determine clinical relevance, results were compared with allowable total error of the respective parameter. Significance was set at P < 0.05. RESULTS: Significant differences between the three storage methods at baseline were found for partial pressure of carbon dioxide (PCO2 ), partial pressure of oxygen (PO2 ), base excess, and total hemoglobin. No significant differences up to T60 were found within collection methods for actual bicarbonate (HCO3 - ), base excess, sodium, potassium, chloride, ionized calcium (iCa), glucose, and BUN. Significant differences within collection methods were found after T0 for creatinine, after 15 minutes for lactate, and after 30 minutes for pH and hematocrit. No significant differences were found for PO2 in samples stored in preheparinized plastic syringes at any time point. CONCLUSIONS: These results suggest that HCO3 - , sodium, potassium, chloride, iCa, glucose, and BUN are comparable within the three storage methods for up to 60 minutes after sampling without resulting in clinically relevant changes.

Acid-Base.

In clinical medicine, evaluation of acid-base balance can be a valuable diagnostic and monitoring tool. Blood gas machines need very small volumes of blood and provide immediate results, making them ideal for use in the emergency room and intensive care setting. This review outlines the stepwise approach to assessment of acid-base balance in dogs, common causes of acid-base abnormalities, and the general approach to treatment.

Point-of-Care Instruments.

Point-of-care testing, or testing done near the patient, allows for rapid results that can theoretically improve patient care and client satisfaction. The value of these results relies on high-quality laboratory practices, including an understanding of the technology by users. Herein is a brief review of point-of-care testing for biochemistry, hematology, coagulation, blood gas analysis, glucometers, and urinalysis, along with available technology with a focus on what information these analyzers can and cannot provide.

Preliminary evaluation of the effects of a 1:1 inspiratory-to-expiratory ratio in anesthetized and ventilated horses.

OBJECTIVE: To describe some cardiorespiratory effects of an inspiratory-to-expiratory (IE) ratio of 1:1 compared with 1:3 in ventilated horses in dorsal recumbency. STUDY DESIGN: Randomized crossover experimental study. ANIMALS: A total of eight anesthetized horses, with 444 (330-485) kg body weight [median (range)]. METHODS: Horses were ventilated in dorsal recumbency with a tidal volume of 15 mL kg-1 and a respiratory rate of 8 breaths minute-1, and IE ratios of 1:1 (IE1:1) and 1:3 (IE1:3) in random order, each for 25 minutes after applying a recruitment maneuver. Spirometry, arterial blood gases and dobutamine requirements were recorded in all horses during each treatment. Electrical impedance tomography (EIT) data were recorded in four horses and used to generate functional EIT variables including regional ventilation delay index (RVD), a measure of speed of lung inflation, and end-expiratory lung impedance (EELI), an indicator of functional residual capacity (FRC). Results were assessed with linear and generalized linear mixed models. RESULTS: Compared with treatment IE1:3, horses ventilated with treatment IE1:1 had higher mean airway pressures and respiratory system compliance (p < 0.014), while peak, end-inspiratory and driving airway pressures were lower (p < 0.001). No differences in arterial oxygenation or dobutamine requirements were observed. PaCO2 was lower in treatment IE1:1 (p = 0.039). Treatment IE1:1 resulted in lower RVD (p < 0.002) and higher EELI (p = 0.023) than treatment IE1:3. CONCLUSIONS AND CLINICAL RELEVANCE: These results suggest that IE1:1 improved respiratory system mechanics and alveolar ventilation compared with IE1:3, whereas oxygenation and dobutamine requirements were unchanged, although differences were small. In the four horses where EIT was evaluated, IE1:1 led to a faster inflation rate of the lung, possibly the result of increased FRC. The clinical relevance of these findings needs to be further investigated.