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To describe acid-base status using the Henderson-Hasselbalch, Stewart and semi-quantitative methods of analysis in a feline haemorrhage-resuscitation model. Randomized crossover study. A total of six domestic cats (mean age, 21 months; weight, 4.9 kg). Venous blood samples were taken before haemorrhage, after haemorrhage at 30 minute intervals during fluid resuscitation and at 24 hours. The cats were anaesthetized and underwent following treatments: no purposeful haemorrhage and resuscitation (NoPHR), purposeful haemorrhage followed by either lactated Ringer's solution (LRS) or 6% tetrastarch 130/0.4 (Voluven) for resuscitation. LRS and Voluven were administered at 60 and 20 mL kg–1 hour–1, respectively, for 120 minutes. Variables used for the analysis methods were measured or calculated from the blood samples and then compared among treatments over time using a general linear mixed model (p < 0.05; data reported as mean and standard deviation). The total blood loss at 120 minutes was 10.2 ± 2.3, 29.3 ± 9.0 and 29.1 ± 6.3 mL kg–1 for NoPHR, LRS and Voluven, respectively. Total volumes of LRS and Voluven administered were 120 and 40 mL kg–1, respectively. All cats became acidaemic during anaesthesia regardless of treatment. The Henderson-Hasselbalch method indicated that anaesthetized cats undergoing severe haemorrhage and resuscitation manifest a mixed acidosis. The Stewart method indicated two counter metabolic processes that contributed to the overall pH—decrease in apparent strong ion difference (acidosis) and decrease in total weak acids (alkalosis). The semi-quantitative method identified the free water and chloride effects as variables causing acidosis and the albumin effect causing alkalosis. In an experimental haemorrhage and resuscitation model in cats, blood pH was similar among treatments over time regardless of severe haemorrhage and resuscitation with LRS or Voluven or mild haemorrhage and no resuscitation. [ABSTRACT FROM AUTHOR]

To determine biomarkers for impending fluid overload during intravenous fluid administration in a feline haemorrhage-resuscitation model. Randomized crossover study. A group of six domestic cats (mean age and weight: 21 months; 4.9 kg, respectively). The cats underwent three treatments, 2 months apart. They were anaesthetized and instrumented to measure a range of physiological, blood gas, haematological and biochemical variables over time. Samples were taken during a health check, before haemorrhage, after haemorrhage and then at 30 minute intervals during fluid resuscitation and 24 hours later. The three treatments were: 1) control, sham haemorrhage and resuscitation; 2) lactated Ringer's solution (LRS); and 3) 6% tetrastarch 130/0.4 (Vol) where the cats underwent a controlled haemorrhage then resuscitation by administering LRS and Vol at 60 and 20 mL kg–1 hour–1, respectively, for 120 minutes. Fluid overload was identified by nasal discharge and radiographic evidence. Biomarkers were variables that exceeded the reference interval for cats during treatment. Potential biomarkers were analysed using receiver operating characteristic curves (p < 0.05). Mean ± standard deviation total blood loss was 10.2 ± 2.3, 29.3 ± 9.0 and 29.1 ± 6.3 mL kg–1 for control, LRS and Vol, respectively. The total volume of LRS and Vol administered was 120 and 40 mL kg–1, respectively. Haematocrit, albumin, magnesium, chloride-to-sodium ratio and sodium-chloride difference were identified as potential biomarkers. These variables exceeded the reference intervals from 30 minutes of resuscitation onwards. A chloride-to-sodium ratio > 0.84 was the most sensitive (90%) and specific (75%) of all potential biomarkers. Changes in physiological variables, haematocrit and albumin were poor biomarkers of impending fluid overload compared with electrolytes. Finding the ideal biomarker to identify impending fluid overload of commonly used intravenous fluids should improve the safety of their administration in cats. [ABSTRACT FROM AUTHOR]

To determine whether physiological, haematological, biochemical or electrolyte variables can predict severe haemorrhage in cats. Randomized crossover study whereby each cat underwent mild and severe haemorrhage, with a 2 month period between events. A group of six domestic cats aged 21 ± 1 months and weighing 4.9 ± 1.2 kg, mean ± standard deviation. Cats were anaesthetized (buprenorphine, alfaxalone, isoflurane in oxygen at a fixed end-tidal concentration of 1.7%) before the haemorrhage event. In total, 34 variables were measured twice (prehaemorrhage and posthaemorrhage). The difference and percent change for each variable were compared between haemorrhage events (paired t test). Significant variables were placed into 13 different ratios (posthaemorrhage value of one variable divided by a posthaemorrhage value of a second variable) and compared (paired t test), and Cohen's d (d) was calculated. Receiver operating characteristic curves were plotted and cut-off values for weak, moderate and strong indicators of severe haemorrhage were obtained. The blood loss was 4.5 ± 1.1 mL kg–1 and 26.8 ± 5.5 mL kg–1 for mild and severe haemorrhage events, respectively. The most significant variables with large effect sizes were heart rate (HR), systolic arterial blood pressure (SAP), end-tidal carbon dioxide (P e′ CO 2), serum albumin, haematocrit and actual bicarbonate ion concentration [HCO 3 −(act)]. The most robust ratios were: 1) shock index (d = –2.8; HR:SAP); 2) HR:P e ′CO 2 (d = –2.9); 3) serum albumin: haematocrit (d = 1.5); and 4) HR:HCO 3 −(act) (d = –1.6). These ratios were included in the final proposed Cat Acute Bleeding Scoring System (CABSS). and clinical relevance Cats subjected to mild and severe haemorrhage demonstrated statistically and clinically relevant changes whereby four ratios could be created to make up the CABSS. The ratios detected and quantified the presence of severe haemorrhage in anaesthetized cats. [ABSTRACT FROM AUTHOR]