Objective—To describe the effects of increasing the extracellular fluid (ECF) volume by approximately 20% on acid-base changes and electrolyte concentrations in anesthetized rats.
Animals—18 adult male Sprague-Dawley rats.
Procedures—Rats were assigned to a control group (n = 6 rats) and a treatment group (12). All rats were anesthetized, and instrumentation and bilateral renal pedicle ligation were performed. The treatment group was infused IV with sterile water throughout a 30-minute period. Acid-base variables and concentrations of electrolytes, lactate, albumin, phosphorus, and hemoglobin were measured before (baseline) and 30 and 60 minutes after onset of infusion. Anion gap, strong ion difference, strong ion gap, and contributions of sodium, chloride, albumin, phosphorus, and lactate concentrations to base excess were calculated at each time point.
Results—Infusion of sterile water led to an increase in ECF volume of approximately 18%. This had no effect on acid-base balance, compared with that in control rats. Infusion of sterile water caused a significant decrease in sodium, chloride, ionized calcium, lactate, and albumin concentrations, compared with concentrations in the control group. Anion gap and calculated effects of sodium, chloride, albumin, and lactate concentrations on base excess at 60 minutes differed significantly between infused and control rats.
Conclusions and Clinical Relevance—Infusion of sterile water did not cause clinically relevant dilutional acidosis. The acidotic impact of water administration was offset by generation of new bicarbonate via carbonic acid equilibration and intracellular buffering in combination with the alkalotic effects of decreases in albumin, phosphorus, and lactate concentrations.
An approximately 2-year-old sexually intact male German Shorthair Pointer was presented for treatment of baclofen toxicosis.
The dog had signs of severe baclofen toxicosis (no gag reflex, intermittent vocalization, and stupor) and received intravenous lipid emulsion (142 mL/kg) as a constant rate infusion over 11 hours. Severe hypertriglyceridemia (29,221 mg/dL; reference interval, 19 to 133 mg/dL) developed, followed by cardiovascular depression (poor peripheral perfusion, hyperlactatemia, and hypertension), severe hypoglycemia (26 mg/dL), acute kidney injury (serum creatinine, 3.6 mg/dL), intravascular hemolysis, and coagulopathy (hypocoagulable thromboelastogram and marked bilateral epistaxis).
TREATMENT AND OUTCOME
Therapeutic plasma exchange was performed in 4 stages to treat the hypertriglyceridemia. For each stage, an approximately 500-mL aliquot of blood (22 mL/kg) was removed and centrifuged, and the patient’s RBCs and allogenic fresh-frozen plasma were returned to the dog. Approximately 1.2 times the dog’s plasma volume was exchanged, reducing the serum triglyceride concentration to 1,349 mg/dL and improving the dog’s cardiovascular function and coagulation. Hours after the procedure was completed, the dog regurgitated and developed acute respiratory distress as a result of presumptive aspiration pneumonia, and the owner elected to have the dog euthanized.
Veterinarians should be aware of possible complications associated with administration of intravenous lipid emulsion, and veterinary-specific guidelines for the maximum dose of intravenous lipid emulsion should be developed to help prevent adverse effects. TPE appears to be an effective method for treating iatrogenic hypertriglyceridemia in dogs.
Objective—To evaluate the effect of dilution of blood
samples with sodium heparin on blood gas, electrolyte,
and lactate measurements in dogs.
Sample Population—Venous blood samples collected
from 6 adult dogs of various breeds.
Procedure—Syringes were prepared with anticoagulant
via 1 of 4 techniques, and the residual volume of
liquid heparin in each type of prepared syringe was
determined. Blood gas values and other selected clinicopathologic
variables were measured in whole
blood samples after collection (baseline) and after
aliquots of the samples were diluted with heparin via
1 of the 4 manual syringe techniques. By use of a
tonometer, whole blood samples were adjusted to 1
of 3 oxygen concentrations (40, 100, or 600 mm Hg)
and the PO2 values were measured at baseline and
subsequent to the 4 heparin dilutions.
Results—The 4 syringe techniques resulted in 3.9%,
9.4%, 18.8%, and 34.1% dilutions of a 1-mL blood
sample. Compared with baseline values, dilution of
blood samples with liquid heparin significantly
changed the measured values of PCO2, PO2, and base
deficit and concentrations of electrolytes and lactate.
Of the variables assessed, measurement of ionized
calcium concentration in blood was most affected by
Conclusions and Clinical Relevance—These findings
in dogs indicate that dilution of blood samples
with heparin can be a source of preanalytical error in
blood gas, electrolyte, and lactate measurements.
Limiting dilution of blood samples with heparin to
< 4% by volume via an evacuation technique of
syringe heparinization is recommended. (Am J Vet Res 2005;66:656–660)
OBJECTIVE To determine common fluid therapy practices of small animal practitioners and identify fluid therapy-related knowledge gaps that may benefit from improved educational efforts, targeted research, or both.
DESIGN Online survey.
SAMPLE 1,496 small animal veterinarians
PROCEDURES An online survey was provided to members of the Veterinary Information Network between December 23, 2013, and January 30, 2014. The survey consisted of 24 questions investigating the administration of crystalloid and synthetic colloid solutions, but not blood products, and focused primarily on the choice of fluid type, frequency of administration, type of patient treated with fluids, treatment with fluids subcutaneously versus IV, and potassium supplementation of fluids. Only responses from practicing small animal veterinarians were included. Not all respondents answered every question, and some questions allowed > 1 answer.
RESULTS Balanced crystalloid solutions were the most common fluid type in all clinical scenarios described. The most common maintenance IV fluid rate reported by respondents (762/1,333 [57%]) was 60 mL/kg/d (27 mL/lb/d); calculation of fluid administration rate by means of body surface area was infrequent. Challenges of fluid therapy included determining the appropriate rate (572/1,496 [38%]) and fluid type (497/1,496 [33%]) and determining the need for potassium supplementation (229/1,496 [15%]).
CONCLUSIONS AND CLINICAL RELEVANCE Small animal veterinarians tended to favor isotonic balanced crystalloid solutions for IV fluid therapy, compared with other common choices such as isotonic saline (0.9% NaCl) solution. Despite its ubiquity, respondents found many aspects of fluid therapy to be challenging, suggesting the need for easy to use, evidence-based guidelines.
Objective—To determine outcome of positive-pressure ventilation (PPV) for 24 hours or longer and identify factors associated with successful weaning from PPV and survival to hospital discharge in dogs and cats.
Design—Retrospective case series.
Animals—124 dogs and 24 cats that received PPV for 24 hours or longer.
Procedures—Medical records were reviewed for signalment, primary diagnosis, reason for initiating PPV, measures of oxygenation and ventilation before and during PPV, ventilator settings, complications, duration of PPV, and outcome. Animals were categorized into 1 of 3 groups on the basis of the reason for PPV.
Results—Group 1 patients received PPV for inadequate oxygenation (67 dogs and 6 cats), group 2 for inadequate ventilation (46 dogs and 16 cats), and group 3 for inadequate oxygenation and ventilation (11 dogs and 2 cats). Of the group 1 animals, 36% (26/73) were weaned from PPV and 22% (16/73) survived to hospital discharge. In group 2, 50% (31/62) were weaned from PPV and 39% (24/62) survived to hospital discharge. In group 3, 3 of 13 were weaned from PPV and 1 of 13 survived to hospital discharge. Likelihood of successful weaning and survival to hospital discharge were significantly higher for group 2 animals, and cats had a significantly lower likelihood of successful weaning from PPV, compared with dogs. Median duration of PPV was 48 hours (range, 24 to 356 hours) and was not as-sociated with outcome.
Conclusions and Clinical Relevance—Results suggested that long-term PPV is practical and successful in dogs and cats.
To describe postobstructive diuresis (POD) in cats undergoing surgical placement of ureteral stents or subcutaneous ureteral bypass systems for treatment of ureteral obstruction in cats and to identify factors associated with duration and maximum severity of POD.
Retrospective case series.
37 client-owned cats with ureteral obstruction treated between August 2010 and December 2014.
Medical records were reviewed, and data extracted included signalment, history, results from physical examinations and clinical laboratory analyses, treatment, urine output, and outcome. Data were evaluated to identify factors associated with POD duration and maximum severity, alone or in combination.
Serum concentrations of creatinine, potassium, phosphorus, and BUN before surgery positively correlated with duration and maximum severity of POD. Absolute changes in serum concentrations of creatinine, potassium, and BUN from before surgery to after surgery positively correlated with POD duration. Cats with anuria before surgery had longer POD than did other cats; however, there was no difference in POD duration or maximum severity with unilateral versus bilateral ureteral obstruction. Thirty-four of 37 (92%) cats survived to hospital discharge, which was not associated with whether ureteral obstruction was unilateral or bilateral. Azotemia resolved in 17 of the 34 (50%) cats that survived to hospital discharge.
CONCLUSIONS AND CLINICAL RELEVANCE
Results of the present study indicated that several factors were associated with POD duration and maximum severity, alone or in combination, and that with intensive management of fluid and electrolyte derangements, regardless of the extent of the original azotemia, a high percentage of cats survived to hospital discharge.