| Background | Hyperosmolar agents are frequently used to decrease intracranial pressure but their effects on electrolyte and acid-base variables have not been prospectively investigated. |
| Rational and Objective | Compare duration and magnitude of changes in electrolyte and acid-base variables after hyperosmolar treatment. |
| Trial Design | Prospective, randomized, non-blinded, experimental cohort study |
| Patient population and location | Twenty-eight client-owned dogs with intracranial hypertension caused by various pathologies. |
| Methods | Fifteen dogs received a single dose (4 mL/kg) of 7.2% hypertonic saline (HTS), 13 dogs received 20% mannitol (MAN) 1 g/kg IV. Electrolyte and acid-base variables were measured before (T0), and 5 (T5), 60 (T60), and 120 (T120) minutes after administration. Variables were compared between treatments and among time points within treatment groups. |
| Endpoints (if applicable) | |
| Results | Mean plasma sodium and chloride concentrations were higher after hypertonic saline (HTS) than mannitol (MAN) at T5 (158 vs 141 mEq/L; 126 vs 109 mEq/L) and significant differences were maintained at all time points. After HTS, plasma sodium and chloride concentrations remained increased from T0 at all time points. After MAN, plasma sodium and chloride concentrations decreased at T5, but these changes were not maintained at T60 and T120. Plasma potassium concentration was lower at T5 after HTS compared with T0 (3.6 vs 3.9 mEq/L) and compared to MAN (3.6 vs 4.1 mEq/L). At T60 and T120, plasma ionized calcium concentration was lower after HTS than MAN (1.2 vs 1.3 mmol/L). No significant differences were found in acid-base variables between treatments. |
| Limitations | A small number of dogs receiving a single dose of a hyperosmolar agent were enrolled in the study.Non-balanced lithium heparin tubes were used for electrolyte and acid-base sample collection via vacutainer system.Full plasma biochemistry results were inconsistently available at baseline and were not repeated at subsequent sampling time points. |
| Clinical Relevance Conclusions | At the administered dose, dogs receiving HTS showed sustained increases in plasma sodium and chloride concentrations, whereas dogs receiving MAN showed transient decreases. Future studies should assess the effects of multiple doses of hyperosmolar agents on electrolyte and acid-base variables. |
