Erythrocytic pyruvate kinase deficiency and AB blood types in Australian Abyssinian and Somali cats

Objective   To determine the frequency of the mutant pyruvate kinase (PK) allele, haematological parameters and AB blood types of Abyssinian and Somali cats in Australia.
Design   Complete blood cell and reticulocyte counts, DNA PK mutation testing and blood typing were performed in all cats.
Results   A total of 60 cats (36 Abyssinians, 24 Somalis) were included (37 females, 23 males). For the mutant PK allele, three female Somalis were homozygous (affected, 5%), 17 cats were heterozygous (carrier, 28%) and 40 cats tested negative (normal, 67%). Pedigree analysis revealed common ancestry of affected and many carrier cats. Of affected cats, two had regenerative anaemias and all had reticulocytosis (range 64–390 × 10⁹/L; P < 0.001 compared with normal or carrier cats). The only consistent historical sign was lethargy. One affected cat was euthanased 18 months after testing, because of anaemia, neutropenia, anorexia and weight loss. The mutant allele frequency was 0.19 overall (0.29 in Somalis, 0.13 in Abyssinians). All cats had blood type A. The commercial blood typing card method incorrectly identified 12 cats as having type AB blood.
Conclusions    The frequency of the mutant PK allele is high in Australia. Screening for PK deficiency is indicated before mating and in individual cats of these breeds, even in the absence of anaemia and especially when there is reticulocytosis. Although all cats in the present study had blood type A, blood type B is common in these breeds worldwide. Retyping of any AB typed cats by a laboratory technique is recommended.     

Validation of the oscillometric blood pressure monitor Vet20 SunTech in anesthetized healthy cats

ObjectiveTo evaluate a veterinary-specific oscillometric noninvasive blood pressure (NIBP) system according to the guidelines of the American College of Veterinary Internal Medicine (ACVIM) Consensus Statement.Study designProspective clinical study.AnimalsA total of 33 client-owned cats (20 females and 13 males).MethodsCats were premedicated with methadone (0.3 mg kg⁻¹) and alfaxalone (2 mg kg⁻¹) intramuscularly. After 15 minutes anesthesia was induced with isoflurane (3%) in 100% oxygen by facemask while breathing spontaneously. A 22 gauge catheter was placed in the median caudal artery and systolic (SAP), diastolic (DAP) and mean (MAP) arterial pressures were measured. NIBP measurements were collected by placing the cuff (40% of limb circumference) on the right or left antebrachium. The agreement between the two methods was evaluated with the Bland–Altman methods, and the oscillometric NIBP device was evaluated using the ACVIM guidelines for validation of devices.ResultsData from 30 of the 33 cats were analyzed. Five paired measurements were taken from each cat, totaling 150 paired measurements. Mean bias (limits of agreements) for SAP, DAP and MAP were 2.7 (−22.7 to 28.1), 0.9 (−22.3 to 24.2) and 1.3 (−20.4 to 23.0). The oscillometric NIBP passed all validation criteria, except correlation which was <0.9 for SAP, DAP and MAP.Conclusions and clinical relevanceThe Vet20 did not meet all validation criteria by the ACVIM. However, all criteria except correlation were met.     

Assessment of feline blood for transfusion purposes in the Dublin area of Ireland

The prevalence of A, B and AB blood types and of feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV) infection was determined in cats in Ireland, in order to determine risk factors for blood taken for transfusion purposes. EDTA blood samples were available from 137 non-pedigree cats and 39 pedigree cats (91 females and 85 males, aged four months to 15.0 years) in the Dublin area of Ireland. Of the 176 EDTA blood samples obtained, 112 (from 92 healthy cats and 20 sick cats) were tested for the presence of both FIV antibodies and FeLV antigens. Blood typing was performed using an immunochromatographic cartridge (CHROM; Alvedia). Testing for FIV and FeLV was performed by ELISA (SNAP FIV/FeLV Combo Test; Idexx Laboratories). Of the 39 pedigree cats, the majority (38 [97.4 per cent]) was type A, and only one (2.6 per cent) was type B. Of the 137 non-pedigree cats, the majority (116 [84.7 per cent]) was type A, 20 (14.6 per cent) were type B, and one (0.7 per cent) was type AB. Of the 92 healthy cats tested, the prevalence of FIV and FeLV positivity was 4.35 and 1.09 per cent, respectively. None of the 20 sick cats tested was FIV-positive; two (10 per cent) of the 20 sick cats were FeLV-positive.     

Effects of propofol on the electrocardiogram and systolic blood pressure of healthy cats pre-medicated with acepromazine

OBJECTIVE: To obtain and analyze the electrocardiogram and systolic blood pressure of cats before, during, and after a continuous infusion of propofol. STUDY DESIGN: Prospective, uncontrolled experimental trial. ANIMALS: Twenty healthy adult crossbred male and female cats aged between 3 and 5 years, weighing 2.8-5.0 kg (mean 3.9 kg). METHODS: Cats were pre-medicated with acepromazine 0.1 mg kg(-1) subcutaneously and anesthesia was induced with intravenous (IV) propofol 6 mg kg(-1) and maintained with a continuous infusion of propofol at 0.5 mg kg(-1) minute(-1) for 60 minutes. Electrocardiographic parameters and systolic blood pressure obtained by Doppler ultrasound were recorded before pre-medication (T0), 30 (T30), and 60 (T60) minutes after beginning the continuous infusion, and 30 minutes after its cessation (T90). Repeated measures anova was used to perform statistical analysis. RESULTS: A significant decrease in heart rate was observed at all time points when compared with T0 values. The PR interval increased significantly at T60 and T90. Systolic blood pressures during anesthesia were significantly lower than at T0 and T90. CONCLUSION AND CLINICAL RELEVANCE: The changes seen were not clinically important in normal cats but given the reduction in heart rate and systolic blood pressure, careful consideration should be given before using this technique in patients in which hypotension or a reduction in heart rate would be poorly tolerated.     

Increasing patient safety in veterinary transfusion medicine: an overview of pretransfusion testing

Objectives – To review the principles and available technology for pretransfusion testing in veterinary medicine and discuss the indications and importance of test performance before RBC transfusion.
Data Sources – Current human and veterinary medical literature: original research articles and scientific reviews.
Summary – Indications for RBC transfusion in veterinary medicine include severe anemia or tissue hypoxia resulting from blood loss, decreased erythrocyte production, and hemolyzing conditions such as immune-mediated anemia and neonatal isoerythrolysis. Proper blood sample collection, handling, and identification are imperative for high-quality pretransfusion testing. Point-of-care blood typing methods including both typing cards and rapid gel agglutination are readily available for some species. Following blood typing, crossmatching is performed on one or more donor units of appropriate blood type. As an alternative to technically demanding tube crossmatching methods, a point-of-care gel agglutination method has recently become available for use in dogs and cats. Crossmatching reduces the risk of hemolytic transfusion reactions but does not completely eliminate the risk of other types of transfusion reactions in veterinary patients, and for this reason, all transfusion reactions should be appropriately documented and investigated.
Conclusion – The administration of blood products is a resource-intensive function of veterinary medicine and optimizing patient safety in transfusion medicine is multifaceted. Adverse reactions can be life threatening. Appropriate donor screening and collection combined with pretransfusion testing decreases the occurrence of incompatible transfusion reactions.     

Effect of immune-mediated erythrocyte agglutination on analysis of canine blood using a multichannel blood cell counting system

Blood from six dogs with in vitro immune-mediated erythrocyte agglutination resulted in analytical errors in directly measured counting and sizing functions on a multichannel blood analysis system with histogram capability. Errors in the directly measured values, mean cell volume (MCV), and erythrocyte count were attributed to agglutinated erythrocyte particles that persisted during the relatively short reagent contact time of the analysis. Agglutinated particles less than 240 fl were visible on erythrocyte histograms and resulted in a false low erythrocyte count and false high MCV. Agglutinated cell particles greater than 240 fl were not present on the histogram scale. Because these latter particles exceeded the upper threshold, they did not influence determination of MCV, but resulted in a further decrease in the erythrocyte count. As a result, the other dependent erythrocyte indices were in error. These included false low hematocrit and false high mean corpuscular hemoglobin concentration (MCHC), when compared to corrected reference blood values. Similar errors occurred when analyzing blood samples that were agglutinated in vitro by incubating erythrocytes with incompatible plasma. The counting and sizing errors observed with electronic counting techniques were eliminated or greatly reduced by incubating blood in cell counting diluent for 10 minutes followed by analysis on a single channel counter with attached particle size analyzer. Error in erythrocyte measurement on a multichannel system may be anticipated if there is overt erythrocyte agglutination in a blood sample, an abnormally high MCHC is reported by the system, or subpopulations of large volume (agglutinated cells) are observed on a volume distribution histogram.     

Effects of cuff size and position on the agreement between arterial blood pressure measured by Doppler ultrasound and through a dorsal pedal artery catheter in anesthetized cats

ObjectiveTo compare the effects of cuff size/position on the agreement between arterial blood pressure measured by Doppler ultrasound (ABP_Doppler) and dorsal pedal artery catheter measurements of systolic (SAP_invasive) and mean arterial pressure (MAP_invasive) in anesthetized cats.Study designProspective study.AnimalsA total of eight cats (3.0–3.8 kg) for neutering.MethodsDuring isoflurane anesthesia, before surgery, changes in end-tidal isoflurane concentrations and/or administration of dopamine were performed to achieve SAP_invasive within 60–150 mmHg. Cuff sizes 1, 2 and 3 (bladder width: 20, 25 and 35 mm, respectively) were placed on distal third of the antebrachium, above the tarsus and below the tarsus for ABP_Doppler measurements. Agreement between ABP_Doppler and SAP_invasive or between ABP_Doppler and MAP_invasive was compared with reference standards for noninvasive blood pressure devices used in humans and small animals.ResultsMean bias and precision (±standard deviation) between ABP_Doppler and SAP_invasive met veterinary standards (≤10 ± 15 mmHg), but not human standards (≤5 ± 8 mmHg), with cuffs 1 and 2 placed on the thoracic limb (7.4 ± 13.9 and –5.8 ± 9.5 mmHg, respectively), and with cuff 2 placed proximal to the tarsus (7.2 ± 12.4 mmHg). Cuff width-to-limb circumference ratios resulting in acceptable agreement between ABP_Doppler and SAP_invasive were 0.31 ± 0.04 (cuff 1) and 0.42 ± 0.05 (cuff 2) on the thoracic limb, and 0.43 ± 0.05 (cuff 2) above the tarsus. ABP_Doppler showed no acceptable agreement with MAP_invasive by any reference standard.Conclusions and clinical relevanceThe agreement between ABP_Doppler and SAP_invasive can be optimized by placing the occlusive cuff on the distal third of the antebrachium and above the tarsus. In these locations, cuff width should approach 40% of limb circumference to provide clinically acceptable estimations of SAP_invasive. Doppler ultrasound cannot be used to estimate MAP_invasive in cats.     

Assessment of blood pressure in cats presented with urethral obstruction

Objective: To determine the arterial blood pressure at presentation in male cats with acute urethral obstruction, and to determine whether there was any correlation between these measurements and concurrent metabolic abnormalities. Design: Prospective, single cohort, observational study. Setting: Private, small animal, after‐hours emergency clinic. Animals: Twenty‐eight client‐owned male cats with acute urethral obstruction and no other known coexisting disease. Interventions: Indirect oscillometric blood pressure measurements obtained before blood sampling and treatment. Measurements and main results: Mean arterial blood pressure (MAP) measurements, physical examination parameters, serum blood urea nitrogen (BUN), creatinine, potassium, phosphorus, total calcium and magnesium concentration, venous pH, lead II electrocardiogram, and urine volume in bladder were evaluated. No cats were hypotensive at presentation; 71% (20/28) were normotensive (median MAP=100 mmHg, range 93–140 mmHg); and 29% (8/28) were hypertensive (median MAP=153 mmHg, range 145–176 mmHg). Compared with hypertensive cats, normotensive cats had significantly lower heart rates (P=0.0201) and lower calcium (P=0.0152). For all 28 cats, MAP correlated with serum potassium and total calcium (P=0.0033). Conclusions: Though potassium and total calcium were inversely and directly correlated respectively with blood pressure in cats with urethral obstruction, none of the cats were hypotensive on presentation. Normotension on admission does not support the absence of biochemical and physical abnormalities in obstructed cats.     

Distribution of blood types in a sample of 245 New Zealand non-purebred cats

AIMS: To determine the distribution of feline blood types in a sample of non-pedigree, domestic cats in New Zealand, whether a difference exists in this distribution between domestic short haired and domestic long haired cats, and between the North and South Islands of New Zealand; and to calculate the risk of a random blood transfusion causing a severe transfusion reaction, and the risk of a random mating producing kittens susceptible to neonatal isoerythrolysis.

METHODS: The results of 245 blood typing tests in non-pedigree cats performed at the New Zealand Veterinary Pathology (NZVP) and Gribbles Veterinary Pathology laboratories between the beginning of 2009 and the end of 2014 were retrospectively collated and analysed. Cats that were identified as domestic short or long haired were included. For the cats tested at Gribbles Veterinary Pathology 62 were from the North Island, and 27 from the South Island.

RESULTS: The blood type distribution differed between samples from the two laboratories (p=0.029), but not between domestic short and long haired cats (p=0.50), or between the North and South Islands (p=0.76). Of the 89 cats tested at Gribbles Veterinary Pathology, 70 (79%) were type A, 18 (20%) type B, and 1 (1%) type AB; for NZVP 139/156 (89.1%) cats were type A, 16 (10.3%) type B, and 1 (0.6%) type AB. It was estimated that 18.3–31.9% of random blood transfusions would be at risk of a transfusion reaction, and neonatal isoerythrolysis would be a risk in 9.2–16.1% of random matings between non-pedigree cats.

CONCLUSIONS: The results from this study suggest that there is a high risk of complications for a random blood transfusion between non-purebred cats in New Zealand. Neonatal isoerythrolysis should be considered an important differential diagnosis in illness or mortality in kittens during the first days of life.     

Effects of blood collection for transfusion on arterial blood pressure, heart rate, and PCV in cats

BACKGROUND: Collection of 50 mL of blood (standard unit) in cats is a common procedure. There are several studies on the health status of donors, but to our knowledge there are no reports on the effects of blood collection on the feline donor. HYPOTHESIS: Collection of a standard unit of blood from cats does not significantly change arterial blood pressure (BP), mean arterial pressure (MAP), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), PCV, and heart rate (HR) in healthy blood donor cats. ANIMALS: Twenty-six healthy blood donor cats (6 spayed females and 20 castrated males). METHODS: An oscillometric method was used to measure MAP, SAP, DAP, and to quantify HR before and after blood collection; PCV was obtained before and immediately after blood collection. RESULTS: Despite a significant decrease (P < .05) in all variables (ie, BP, PCV, HR) after blood collection, no adverse events were observed. CONCLUSIONS AND CLINICAL IMPORTANCE: The collection of a unit of blood for transfusion from healthy donor cats weighing more than 5 kg appears to be safe, but this procedure leads to a decrease in arterial BP, PCV, and HR.