Evaluation of the i-STAT Alinity v in a veterinary clinical setting

Many point-of-care (POC) analyzers are available for the measurement of electrolytes and acid-base status in animals. We assessed the precision of the i-STAT Alinity v, a recently introduced POC analyzer, and compared it to 2 commonly used and previously validated POC analyzers (i-STAT 1, Stat Profile pHOx Ultra). Precision was evaluated by performing multiple analyses of whole blood samples from healthy dogs, cats, and horses on multiple i-STAT Alinity v analyzers. For comparison between analyzers, whole blood samples from dogs and cats presented to the emergency room were run concurrently on all 3 POC instruments. Reported values were compared by species (dogs and cats only) using Pearson correlation, and all values from all species were analyzed together for the Bland–Altman analysis. Results suggested that the i-STAT Alinity v precision was very good, with median coefficients of variability <2.5% for all measured parameters (except the anion gap), with variable ranges of coefficients of variation. In addition, good-to-excellent correlation was observed between the i-STAT Alinity v and i-STAT 1, and between the i-STAT Alinity v and Stat Profile pHOx Ultra for all parameters in both cats and dogs, respectively. In this cohort, the i-STAT Alinity v had clinically acceptable bias compared to the currently marketed analyzers and can be used for monitoring measured analytes in cats and dogs, although serial measurements in a single animal should be performed on the same analyzer whenever possible.     

Blood gas, oxygen saturation, pH, and lactate values in elasmobranch blood measured with a commercially available portable clinical analyzer and standard laboratory instruments

Blood gas, pH, and lactate data are often used to assess the physiological status and health of fish and can often be most valuable when blood samples are analyzed immediately after collection. Portable clinical analyzers allow these measurements to be made easily in the field. However, these instruments are designed for clinical use and thus process samples at 37 degrees C. A few studies have validated the use of portable clinical analyzers for assessing blood gases and acid-base profiles in teleosts, but equivalent data are not available for elasmobranchs. We therefore examined the relationship of blood gas, pH, and lactate values measured with an i-STAT portable clinical analyzer with those measured using standard laboratory blood gas (thermostatted to 25 degrees C) and lactate analyzers in samples taken from three species of carcharhiniform sharks. We found tight correlations (r2 > 0.90) between these methods for pH, pO2, pCO2, and lactate level values. We thus developed species-specific equations for converting blood values measured with an i-STAT portable clinical analyzer to those taken at 25 degrees C. Additional studies need to address a wider range of temperatures and elasmobranch species.     

Measurement of ionized calcium in canine blood samples collected in prefilled and self-filled heparinized syringes using the i-STAT point-of-care analyzer

BACKGROUND: Heparinized syringes are commonly used with point-of-care analyzers (eg, i-STAT) to measure ionized calcium (iCa(2+)); however there is little information about the validity of their use in canine patients. OBJECTIVE: To examine the suitability of prefilled (40 IU heparin/mL) and self-filled (150 IU heparin/mL) heparinized syringes for iCa(2+) measurements using the i-STAT analyzer. METHODS: Forty-seven blood samples were collected from 41 canine patients. Two milliliters of blood were collected into a 2-mL nonanticoagulated (NA) syringe, a commercially available preheparinized (PH) syringe (dry calcium-balanced lithium heparin, 40 IU/mL), and a 2-mL self-filled heparinized (SH) syringe (liquid sodium heparin, 150 IU/mL). iCa(2+) was measured in the sample using the i-STAT analyzer and a wet-reagent analyzer (KoneLab 30i) used as the reference instrument. Data were analyzed using paired t-tests, Pearson correlation coefficient, and Bland-Altman difference plots. RESULTS: There was no significant difference between the results obtained from NA and PH syringes using the i-STAT analyzer, and the correlation was excellent (r =.97). The i-STAT values from the SH syringes (mean, 1.07 mmol/L) were significantly lower (P<.001) than those from the NA syringes (mean, 1.38 mmol/L). iCa(2+) was significantly higher with the i-STAT analyzer than with the KoneLab analyzer for both the PH (mean i-STAT, 1.38 mmol/L vs mean KoneLab, 1.30 mmol/L) and SH (mean i-STAT, 1.07 mmol/L vs mean KoneLab, 1.03 mmol/L) samples. CONCLUSIONS: Blood samples collected in the PH syringes used in this study can be used interchangeably with those collected in NA syringes for measuring iCa(2+) using the i-STAT analyzer. SH syringes with high-concentration heparin products (5000 IU/mL) are unsuitable for measuring iCa(2+) because they cause clinically significant underestimations. Although there was good correlation between the i-STAT and KoneLab analyzers, the results should be interpreted using analyzer-specific reference intervals.     

The accuracy of the i-STAT portable analyser for measuring blood gases and pH in whole-blood samples from dogs

To assess the suitability of the i-STAT portable analyser for use by non-laboratory personnel, we measured blood gases and pH in venous blood samples from 100 dogs. Deming's regression and bias plots were used to compare i-STAT results with those obtained by laboratory professionals using two different autocalibrated benchtop analysers. Overall accuracy of the portable analyser proved excellent for pH, pO(2), and pCO(2) (r=0.978, 0.968 and 0.997, respectively), with Deming's regression slopes close to 1.00 (0.96, 0.97 and 1.08 for pH, pO(2), and pCO(2), respectively) and intercepts close to zero (0.28, 0.47 kPa and 0.46 kPa for pH, pO(2), and pCO(2), respectively). The accuracy of the i-STAT was also satisfactory for calculated parameters: bicarbonates, total CO(2), base excess and oxygen saturation. Our findings show this portable analyser to be a valid substitute for expensive benchtop analysers in situations requiring mobility, or when small numbers of tests are to be performed by users not specialized in laboratory techniques.     

Blood values of juvenile northern elephant seals (Mirounga angustirostris) obtained using a portable clinical analyzer

Background — Sick, injured, or orphaned juvenile northern elephant seals ( Mirounga angustisrostris ) treated at rehabilitation centers frequently present with abnormalities in blood sodium, potassium, chloride, BUN, and glucose concentrations, and HCT. These abnormalities could be detected rapidly using a portable blood analyzer, but the results with this analysis method do not necessarily equate with those obtained using other techniques.
Objective — The objective of this study was to better assess the clinical relevance of blood values obtained from a portable analyzer and to compare the results with values obtained using more common methods of analysis.
Methods — Heparinized whole blood samples were collected from 20 rehabilitated juvenile northern elephant seals. A portable clinical analyzer (i-STAT, i-STAT Corp, East Windsor, NJ, USA) was used to establish baseline values. Serum biochemical values were obtained using an automated chemistry analyzer (Olympus AU5200, Olympus America, Melville, NY, USA). HCT was determined using EDTA whole blood and a cell counter.
Results — Using the portable analyzer, mean (minimum-maximum) values were obtained for sodium, 143 (132–146) mmol/L; potassium, 4.4 (3.9–5.8) mmol/L; chloride, 106 (101–109) mmol/L; BUN, 1.8 (1.1–2.4) mmol/L; glucose, 7.55 (5.99–8.49) mmol/L; and HCT, 0.55 (0.52–0.61) L/L. Average differences between methods were small for potassium (-0.45 mmol/L), BUN (0.1 mmol/L), and HCT (0.037 L/L) but were large for sodium (-6.8 mmol/L), chloride (-6.4 mmol/L), and glucose (-0.56 mmol/L).
Conclusions — These results suggest that the i-STAT portable analyzer could be useful for clinically assessing juvenile elephant seals. However, when making medical decisions, the clinician should be aware of differences associated with various analyzers and sample types.     

Comparison of the bovine blood gas parameters produced with three types of portable blood gas analyzers

BackgroundA definite diagnosis should be made in the bovine practice field, however, it was difficult to perform laboratory analysis immediately. Currently, three types of portable blood gas analyzers are available in Korea.ObjectivesThis study aimed to evaluate the correlations among these three analyzers.MethodsSeventy-two plasma samples from Holstein-Friesian cows were used for blood gas analysis, and three instruments (EDAN i15 Vet, VETSCAN i-STAT, and EPOC) were operated simultaneously. Moreover, plasma calcium levels were compared between these portable analyzers and blood chemistry device, which is usually used in a laboratory environment. Pearson analysis was performed to confirm the correlation of each parameter produced with the three instruments and blood chemistry analyzer.ResultsAs results, high correlation was observed in parameters of pH, pO₂, potassium ion, ionized calcium, and glucose (p < 0.001, r > 0.7). In addition, pCO₂ showed a moderate correlation among the three analyzers (p < 0.001, r > 0.5), and there was no correlation among all instruments for sodium ions. There was also a high correlation between ionized calcium from the three portable devices and total calcium from the biochemistry analyzer (p < 0.001, r > 0.9).ConclusionsIn conclusion, there was a high correlation between results from the three different blood gas analyzers used in the bovine clinical field in Korea. Thus, a consistent diagnosis can be made even with different equipment if the operator is aware of the strengths and weaknesses of each piece of equipment and operates it properly.     

Accuracy of a portable blood gas analyzer incorporating optodes for canine blood

The accuracy of a portable blood gas analyzer (OPTI 1) was evaluated using canine blood and aqueous control solutions. Sixty-four arterial blood samples were collected from 11 anesthetized dogs and were analyzed for pH, partial pressure of carbon dioxide (PCO2) partial pressure of oxygen (PO2), and bicarbonate concentration ([HCO3-]) values by the OPTI 1 and a conventional blood gas analyzer (GASTAT 3). The conventional analyzer was considered as a standard against which the OPTI 1 was evaluated. Comparison of OPTI 1 results with those of GASTAT 3 by linear regression analysis revealed a high degree of correlation with the GASTAT 3 (r = .90-.91). The mean +/- SD of the differences between OPTI 1 and GASTAT 3 values was -0.008 +/- 0.017 for pH, -0.88 +/- 3.33 mm Hg for PCO2, 3.71 +/- 6.98 mm Hg for PO2, and -0.34 +/- 1.45 mEq/L for [HCO3-]. No statistically significant difference was found between the OPTI 1 and the GASTAT 3. Agreement between these 2 methods is within clinically acceptable ranges for pH, PCO2, PO2, and [HCO3-]. The coefficients of variation for measured pH, PCO2, and PO2 values of 3 aqueous control solutions (acidic, normal, and alkalotic) analyzed by the OPTI 1 ranged from 0.047 to 0.072% for pH, 0.78 to 1.81% for PCO2, and 0.73 to 2.77% for PO2. The OPTI 1 is concluded to provide canine blood gas analysis with an accuracy that is comparable with that of conventional benchtop blood gas analyzers.     

Selected blood chemistry and gas reference ranges for broiler breeders using the i-STAT handheld clinical analyzer

Selected blood chemistry and gas reference ranges for clinically healthy broiler breeder hens were established using CG8+ cartridges in an i-STAT handheld point-of-care clinical analyzer. Samples from 165 hens (25-36 wk of age), representing three broiler breeder strains reared by four integrators, were evaluated. A standardized sampling technique was developed to minimize instrument error readings. The following reference ranges and means, respectively, were determined: sodium (141.6-152.6, 147.1 [mmol/L]), potassium (4.1-5.7, 4.9 [mmol/L]), ionized calcium (1.20-1.73, 1.47 [mmol/L]), glucose (207.2-260.7, 234.0 [mg/dl]), hematocrit (21.3-30.8, 26.1 [% packed cell volume]), hemoglobin (7.3-10.5, 8.9 [g/dl]), pH (7.28-7.57, 7.42), carbon dioxide partial pressure (25.9-49.5, 37.7 [mm Hg]), oxygen partial pressure (32.0-60.5, 46.2 [mm Hg]), bicarbonate (18.9-30.3, 24.6 [mmol/L]), total carbon dioxide (19.9-31.5, 25.7 [mmol/L]), base excess (-6.8 to 7.2, 0.2), and oxygen saturation (70.6-93.3, 82.0 [%]). Wide ranges in blood gases and base excess occurred in all strains. Cobb strain hens had significantly lower glucose and higher partial and saturated oxygen values compared with two Ross strains. Significant differences in several blood parameters were found among different integrators and in older postpeak production birds. The i-STAT handheld point-of-care clinical analyzer provides rapid, relatively low cost, blood chemistry values that are useful for investigating broiler breeder flock diseases of unknown or uncertain etiology, especially those suspected of having a metabolic cause.     

Evaluation of a new handheld point-of-care blood gas analyser using 100 equine blood samples

Objectives

To determine whether the Enterprise point-of-care blood analysis system (EPOC) produces results in agreement with two other blood gas analysers in regular clinical use (i-STAT and Radiometer ABL77) and to investigate the precision of the new machine when used with equine whole blood.

Haematology, blood chemistry and urine parameters of free-ranging plains viscachas (Lagostomus maximus) in Argentina determined by use of a portable blood analyser (i-STAT) and conventional laboratory methods

Haematology, blood chemistry and urine values were determined for 44 adult free-ranging plains viscachas (Lagostomus maximus; Rodentia, Chinchillidae) in their pampas habitat in central Argentina. The study animals were captured in the wild and anaesthetized with a ketamine-xylazine combination for physical examination and sampling. Blood was obtained by venipuncture of the saphenous vein. Results for many of the blood parameters fall within the reference ranges for pet chinchillas. Differentiation of white blood cells revealed a predominantly neutrophil count for plains viscachas, while chinchillas have predominantly lymphocytes. Mean values for blood urea nitrogen, creatinine, aspartate aminotransferase and sodium were higher than the upper limit of the reference range for pet chinchillas. The results of seven analytes (haematocrit, haemoglobin, glucose, blood urea nitrogen, sodium, potassium, chloride) were compared by using both a portable blood analyser (i-STAT) in the field and conventional laboratory methods. In general, correlation and agreement between the two methods were low for most parameters.     

Accuracy and precision of the portable StatPal II and the laboratory-based NOVA stat profile 1 for measurement of pH, P(CO2), and P(O2) in equine blood

OBJECTIVE: To investigate the accuracy and precision of the portable, battery-powered StatPal II and the laboratory-based NOVA StatProfile 1 blood gas and pH analyzers for use in analysis of equine blood. STUDY DESIGN: Patient sample comparison and whole blood tonometry. SAMPLE POPULATION: Patient sample comparison: 125 arterial or venous blood samples from 49 healthy, awake, or anesthetized horses or ponies. Tonometry: venous blood samples from 11 healthy Thoroughbred horses. MATERIALS AND METHODS: Arterial and venous blood taken from awake and anesthetized equine patients was placed in an ice-water bath, then analyzed within 30 minutes of collection. Bias and limits of agreement between analyzers in measurement of pH, P(CO2), and P(O2) were calculated according to the method of Bland and Altman. Tonometry, using analyzed gases with a range of P(O2) of 28 to 286 mm Hg and P(CO2) of 21 to 85 mm Hg, was performed on equine whole blood or blood with abnormally high (55%) or low (20%) hematocrit. Samples were introduced directly from the tonometer into the analyzers. Inaccuracy (% of target value) and imprecision (coefficient of variation) were determined for each instrument. In addition, results of analysis of blood samples introduced into the analyzers at 36 degrees C, 0 to 3 degrees C, and 22 degrees C were compared. RESULTS: In the patient sample comparisons, bias between analyzers (StatPal-NOVA) for measurement of P(O2) less than 60 mm Hg was -0.33+/-6.2 mm Hg (x +/-2 SD) and for P(O2) between 60 and 110 mm Hg bias was -1.48+/-9.2 mm Hg. Bias was 46.5+/-67 mm Hg (significantly different from bias at the lower P(O2) levels) for measurement of P(O2) values of 111 to 505 mm Hg, and at P(O2) values greater than 110 mm Hg, bias increased with increasing P(O2). During the course of the study, a significant shift in bias between instruments occurred for P(CO2) and pH measurement, coincident with a change of P(CO2) and pH electrodes in the NOVA and use of a new lot of StatPal sensors. Bias (StatPal-NOVA) for P(CO2) before and after the electrode change was -3.74+/-4.2 and -0.88+/-6.8 mm Hg, and bias for pH before and after the electrode change was 0.026+/-0.034 and -0.024+/-0.038. The change in bias was significant (P<.05). In the whole blood tonometry trials, mean recovered values of P(CO2) and P(O2) from blood with a normal hematocrit ranged from 94% to 109% of target values for StatPal and from 98% to 107% for NOVA. Imprecision ranged from 3.3% to 5.3% for StatPal and from 2.2% to 4.3% for NOVA. With extremes of hematocrit (55% and 20%), StatPal's mean recovered P(CO2) values were 115% and 112% of the target value of 21 mm Hg, whereas NOVA's recovered P(CO2) values were similar to those recovered from samples with normal hematocrit. Introduction of cold blood samples (0 to 3 degrees C) into StatPal resulted in P(CO2) readings that were approximately 2 mm Hg lower than those of 22 degrees C and 36 degrees C samples (P<.05). No other effects of sample temperature were found for either instrument. CONCLUSIONS: StatPal and NOVA are of similar accuracy and demonstrate acceptable precision for measurement of P(CO2) and P(O2) in equine blood with values in the normal arterial and venous range. Mean recovered values during tonometry differed by as much as 10% between instruments, indicating that they should not be used interchangeably for a single patient or for a group of subjects in a research setting. CLINICAL RELEVANCE: The StatPal is a portable blood gas analyzer of acceptable accuracy and precision, for clinical or investigational work in horses.     

THE USE OF CZECHOSLOVAK VENTILATOR ELVENT IN ARTIFICIAL VENTILATION DURING HALOTHANE NARCOSIS IN THE DOG

Czechoslovak ventilator ELVENT designed for artificial respiration in human was tested in dogs. SO experimental dogs were divided into 3 groups. The animals were under halothane anaesthesia and myorelaxation with artificial ventilation for 120–180 min. Before, during and after experiments at set intervals heart rate, temperature, ECG and acid-base balance (ABB) from venous and arterial blood values of blood-gases, concentrations of potassium and haemoglobin were determined. The model of ventilation program chosen in the third series appears to be the most acceptable for the clinical use. Ventilator parameters were set as follows: respiratory rate from 15 to 20 breaths per min, respiratory min volume from 1.5 to 3 litres, tidal volume from 0.15 to 03 litres. The duration of inspiration was from 0.8 to 1.2 sec., the duration of expiration was double this. Changes in ABB parameters and the tension of blood gases demonstrated the development of respiratory acidosis, in the majority of cases partly compensated.     

Validation of the bovine blood calcium checker as a rapid and simple measuring tool for the ionized calcium concentration in cattle

Point-of-care (POC) devices that veterinary practitioners can use to easily and rapidly measure blood ionized calcium (iCa) levels in cows immediately after withdrawing a blood sample on the dairy farm are needed. Aims of present studies was to compare the commercially available ion-selective electrode handheld iCa meter (bovine blood iCa checker) with the benchtop blood gas analyzer GEM premier 3500 and handheld analyzer i-STAT 1. Sixty-two paired-point whole blood samples were obtained from three cows with hypocalcemia experimentally induced by Na₂-EDTA infusion. Whole blood samples were also obtained from the 36 cows kept on a farm in field conditions. The results using the bovine blood iCa checker correlated with those using the GEM premier 3500 and i-STAT 1. Bovine blood iCa checker was “compatible” with the GEM premier 3500 and i-STAT 1 because the frequency of differences between the measurements within ± 20% of the mean were 100% (65/65, >75%) and 90.8% (59/65, >75%), respectively. In the field trial, the blood iCa concentration measured by the bovine blood Ca checker was significantly positively correlated with that measured by the i-STAT 1 portable analyzer. Bovine blood iCa checker was “compatible” with the i-STAT 1 because the frequency of differences between the measurements within ± 20% of the mean was 100% (36/36, >75%). Results from these findings, the bovine blood iCa checker may be applied as a simplified system to measure the iCa concentration in bovine whole blood.     

Comparison of whole blood and plasma potassium concentrations in dogs using the Reflovet system

Background: The Reflovet system is designed for chemical analysis of whole blood. However, plasma or serum is recommended for potassium analysis because of possible interference from RBC potassium. Because RBC potassium concentration is low in most canine erythrocytes, however, there should be little or no interference.
Objective: The objective of this study was to compare potassium results obtained in whole blood and in plasma from dogs using the Reflovet system.
Methods: Blood samples were collected from 104 dogs into lithium-heparin tubes. The potassium concentration was measured in whole blood, and subsequently the PCV was measured. Samples were centrifuged and the potassium concentration was measured in plasma. Comparisons were made using Deming's regression and Bland-Altman difference plots.
Results: There was very good correlation between results of potassium measurements in whole blood and plasma ( r = 0.93). Potassium values were moderately lower in whole blood: Potassium_blood= 0.912 × Potassium _plasma+ 0.119. Hemolysis had a negligible effect on the results, but the difference increased with the PCV value. In more than 90% of samples, the difference between the 2 measurements was ≤ 0.3 mmol/L.
Conclusion: There is only a negligible difference in most cases between potassium values in canine plasma and whole blood using the Reflovet system.     

Cardiopulmonary effects of a halothane/oxygen combination in healthy cats.

The effects of a halothane/oxygen combination on the cardiopulmonary function of 11 healthy cats were studied. Test parameters included cardiac output, measured via thermo-dilution, heart rate, respiratory rate, arterial blood pressure (systolic, diastolic and mean) and blood gas analysis. Values for systemic vascular resistance, cardiac index and stroke volume were calculated from these data. Cardiac output, cardiac index, heart rate, stroke volume, arterial blood pressure (systolic, diastolic and mean) and arterial blood pH were significantly decreased (p less than 0.001). Respiratory rate was also significantly decreased (p less than 0.007) with arterial CO2 tension being significantly increased (p less than 0.001). Statistically significant changes, where seen, persisted for the duration of the anesthetic period. Arterial O2 tension and systemic vascular resistance remained unchanged. All parameters returned to near pretest values within 30 minutes following cessation of halothane anesthesia.     

Evaluation of an automated tabletop blood biochemical analyzer for the veterinary clinical pathology laboratory

The importance of accurate quantitative blood biochemical analysis for the diagnosis and management of disease is recognized by most veterinarians. In recent years, several biochemical analyzers have become available for the veterinary market. One of these analyzers was evaluated for its suitability in measuring several biochemical variables--alkaline phosphatase, urea nitrogen, creatinine, glucose, alanine transaminase (dog and cat only), and aspartate transaminase (horse only)--in dogs, cats, and horses. Instrument within-day precision ranged from 1.0 to 7.1%, and between-day precision ranged from 1.6 to 7.4%. During the 6-month period of the study, the analyzer required recalibration for only 1 analyte (creatinine). Concentrations of individual analytes were similar when blood (collected in anticoagulant), plasma, and serum were assayed in parallel. The accuracy of the analyzer, as measured by correlation to a reference method, ranged from 0.861 for creatinine in horses to greater than 0.950 for each of the other analytes in the 3 species. Mean values for each analyte were similar, except for alkaline phosphatase, which had consistently lower values by use of the analyzer method. A data base was established for reference values in each species.     

Comparison of measured oxyhemoglobin saturation and oxygen content with analyzer-calculated values and hand-calculated values obtained in unsedated healthy dogs

OBJECTIVE: To compare direct measurements of canine oxyhemoglobin (HbO2) saturation and blood oxygen content (ContO2) in healthy dogs with analyzer-calculated values derived by use of a human HbO2 relationship and with hand-calculated values derived by use of a canine HbO2 relationship. ANIMALS: 17 healthy dogs. PROCEDURE: 3-mL samples of heparinized arterial and jugular venous blood were collected from each dog. The pH, Pco2, Po2, hemoglobin, HbO2, carboxyhemoglobin, methemoglobin, and ContO2 were measured; HbO2 and ContO2 were calculated automatically by analyzers and also hand-calculated. Blood gas analyzer-calculated and hand-calculated HbO2 values were compared with co-oximeter-measured HbO2 values. Analyzer-calculated and hand-calculated ContO2 values were compared with oxygen content analyzer-measured values. RESULTS: Hand-calculated HbO2 values for arterial and jugular venous samples were slightly but significantly lower than those calculated by a blood gas analyzer or obtained from a co-oximeter. Hand-calculated and analyzer-calculated arterial and venous ContO2 were similar to measured values. CONCLUSIONS AND CLINICAL RELEVANCE: Although certain HbO2 and ContO2 values generated by use of the different methods were significantly different, these differences are unlikely to be clinically important in healthy dogs.     

Canine complete blood counts: a comparison of four in‐office instruments with the ADVIA 120 and manual differential counts

Background: With more use of bench‐top in‐office hematology analyzers, the accuracy of reported values is increasingly important. Instruments use varied methods for cell counting and differentiation, and blood smears may not always be examined. Objective: The purpose of this study was to compare canine CBC results using 4 bench‐top instruments (Hemavet 950, Heska CBC‐Diff, IDEXX LaserCyte, and IDEXX VetAutoread) with ADVIA 120 and manual leukocyte counts. Methods: EDTA‐anticoagulated canine blood samples (n=100) were analyzed on each instrument. Manual differentials were based on 100‐cell counts. Linear regression, difference plots, paired t‐tests, and estimation of diagnostic equivalence were used to analyze results. Results: Correlations of HCT, WBC, and platelet counts were very good to excellent between all in‐office instruments and the ADVIA 120, but results varied in accuracy (comparability). Hemavet 950 and Heska CBC‐Diff results compared best with ADVIA results and manual leukocyte differentials. HCT and platelet counts on the IDEXX VetAutoread compared well with those from the ADVIA. Except for neutrophil counts, leukocyte differentials from all instruments compared poorly with ADVIA and manual counts. Reticulocyte counts on the LaserCyte and VetAutoread compared poorly with those from the ADVIA. Conclusions: The Hemavet 950 and Heska CBC‐Diff performed best of the 4 analyzers we compared. HCT, WBC, and platelet counts on the LaserCyte had minimally sufficient comparability for diagnostic use. Except for neutrophils (granulocytes), leukocyte differential counts were unreliable on all in‐office analyzers. Instruments with a 5‐part leukocyte differential provided no added benefit over a 3‐part differential. Assessment of erythrocyte regeneration on the LaserCyte and VetAutoread was unreliable compared with the ADVIA 120.     

Mechanics of breathing in goats

Common pulmonary function tests used in man and domestic mammals were adapted to the goat. Requirements for intrathoracic pressure record and pulmonary function investigation were determined. The elastance of the mid-thoracic portion of the oesophagus was measured in 17 healthy goats. The calculated percentage error in identifying the endoesophageal intrathoracic pressure decreased with somatic growth, and was found to be smaller than 2 per cent for adult goats. The location of the oesophageal balloon catheter used to measure the intrathoracic pressure was standardised. The following regression equation calculated between the length of catheter (Lcat) and the thoracic circumference (TC) was found: Lcat (cm) = 6.19 +/- 0.7163 X TC (cm) (R2 = 0.96). The influence of the dead space of a face mask on respiration pattern and arterial blood gas were studied. There were no significant changes in arterial partial pressure of oxygen (PaO2) and carbon dioxide (PaCO2), pHa, breathing frequency and intrathoracic pressures. The influence of head and neck position was investigated. Upper airway resistance (Ruaw), measured with the head in a normal position did not significantly differ from values obtained with the head in a horizontal position. Ruaw measured with the head in a vertical position was considerably increased. Arterial blood gas tension and pulmonary mechanics were measured to assess the reproducibility of pulmonary function measurements. Variability in blood gas tension, tidal volume and minute volume is small. The variability of peak to peak intrathoracic pressure change (max delta Plp), dynamic lung compliance (Cdyn), total pulmonary resistance (RL) and Rt were relatively large.     

Cardiopulmonary effects of a ketamine/acepromazine combination in hypovolemic cats.

The cardiopulmonary effects of a ketamine/ acepromazine combination was studied in ten cats subjected to a 25% whole blood volume loss. Test parameters included cardiac output, measured via thermodilution, heart rate, respiratory rate, arterial blood pressure (systolic, diastolic and mean) and blood gas analysis. Values for cardiac index, stroke volume and systemic vascular resistance were calculated from these data. Posthemorrhage, cardiac output, cardiac index, stroke volume, heart rate and measurements of arterial blood pressure were significantly decreased (p less than 0.05). Following the induction of ketamine/ acepromazine anesthesia, cardiac output, cardiac index, stroke volume and heart rate showed mild but statistically insignificant declines and were above their respective posthemorrhage values 120 min into ketamine/ acepromazine anesthesia. Measurements of arterial blood pressure showed further declines from their respective posthemorrhage values that were statistically significant (p less than 0.05). Following hemorrhage, respiratory rate increased significantly (p less than 0.05), associated with a fall in arterial CO2 tension. During ketamine/ acepromazine anesthesia, respiratory rate showed a dramatic and significant decline (p less than 0.05) with arterial CO2 tension rising to prehemorrhage values. Systemic vascular resistance, arterial O2 tension and pH remained essentially unchanged throughout the experimental period.