Research Article | 23 Feb 2026

Venous blood gas kinetics and acid–base correction during incremental intermittent hemodialysis in dogs with advanced renal failure

Sachin Sachin1 , Randhir Singh2 , Raj Sukhbir Singh2 , and Gurpreet Singh Preet2 Show more
VETERINARY WORLD | pg no. 667-677 | Vol. 19, Issue 2 | DOI: 10.14202/vetworld.2026.667-677
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Abstract

          
Background and Aim: Acid–base disturbances, particularly metabolic acidosis, are common in dogs with advanced renal failure and contribute substantially to morbidity and prognosis. Intermittent hemodialysis (IHD) is increasingly used when conventional therapy fails; however, physiological monitoring parameters for incremental intermittent hemodialysis (i-IHD) in dogs remain poorly defined. Venous blood gas (VBG) analysis offers a safer and more practical alternative to arterial sampling, yet its utility during i-IHD has not been systematically evaluated. This study aimed to characterize longitudinal changes in VBG and hemato-biochemical parameters before and after consecutive i-IHD sessions in dogs with renal failure. 
Materials and Methods: In this prospective observational study, 45 client-owned dogs with severe azotemia (serum creatinine >5 mg/dL) due to acute kidney injury (AKI) stage IV–V or chronic kidney disease (CKD) stage IV were enrolled. All dogs underwent three consecutive i-IHD sessions with stepwise increases in treatment intensity. Venous blood samples were collected immediately before and after each session for VBG analysis, including pH, bicarbonate (HCO₃⁻), total carbon dioxide (TCO₂), partial pressures of carbon dioxide (pCO₂) and oxygen (pO₂), base excess, anion gap, and cerebral oxygen saturation, along with hemato-biochemical profiling. Dialysis adequacy was assessed using Kt/V, urea reduction ratio, and creatinine reduction ratio. Pre- and post-dialysis values were compared using paired statistical analyses. 
Results: Dogs exhibited mild-to-moderate metabolic acidosis before i-IHD. Across all sessions, i-IHD produced a consistent and significant correction of acid–base imbalance, evidenced by normalization of pH and marked increases in HCO₃⁻ and TCO₂ (p < 0.01). A modest but significant rise in pCO₂ accompanied bicarbonate repletion, while the anion gap remained within the lower borderline range, indicating non-anion gap metabolic acidosis. Significant reductions in blood urea nitrogen and creatinine (approximately 25%–40% per session) confirmed effective solute clearance, with adequacy indices improving progressively across sessions. Electrolyte abnormalities, particularly hyperkalemia, were effectively corrected. 
Conclusion: I-IHD effectively restores acid–base and biochemical homeostasis in dogs with advanced renal failure. Serial VBG monitoring provides clinically meaningful, session-wise information and represents a practical tool for guiding i-IHD without the risks of arterial sampling. 
          
Keywords: acid–base balance, canine renal failure, hemodialysis, incremental intermittent hemodialysis, metabolic acidosis, renal replacement therapy, venous blood gas, veterinary nephrology.