Furosemide continuous rate infusion diluted with 5% dextrose in water or hypertonic saline in normal adult dogs: a pilot study

Objective

The goal of this study was to investigate the short-term safety and diuretic efficacy of furosemide constant rate infusion (CRI) diluted with 5% dextrose in water (D5W) compared to dilution with 2.4% hypertonic saline in healthy dogs.

Animals

Six healthy dogs.

Methods

Dogs were studied in a randomized, blinded, crossover manner. Furosemide 3.3mg/kg was diluted to 2.2mg/mL with either 1.5mL/kg D5W for the DEX method or with 1.0mL/kg D5W and 0.5mL/kg of 7.2% hypertonic saline for the H-SAL method. After a 0.66mg/kg furosemide IV bolus, the infusion rate was 0.3 mL/kg/hr for 5 h such that both methods delivered 0.66 mg/kg/hr (total 3.3mg/kg) furosemide in equal volume for the study duration. Urine output, water intake, central venous pressure (CVP), physical parameters, furosemide concentrations, blood and urine electrolytes, and urine aldosterone to creatinine ratio (UAldo:C) were evaluated.

Results

Measured variables were not different between methods but showed changes over time consistent with diuresis. Mean CVP decreased over time similarly for both methods. Plasma furosemide and urine concentrations were stable and not different between methods. Both furosemide CRI methods showed an increase in the UAldo:C, however, the rise was greater for DEX than for H-SAL.

Conclusions

Diuresis was similar for both furosemide CRI methods; however, the H-SAL method induced less renin-angiotensin-aldosterone system activation than the DEX method. The absence of intravascular volume expansion based on CVP suggests that dilution of a furosemide CRI with 2.4% hypertonic saline may be well tolerated in heart failure.