Intravenous Bolus Fluid Therapy Versus No Fluid Therapy Prior to Pericardiocentesis in Dogs: A Randomized Controlled Trial in 30 Dogs

Objective To determine the cardiovascular and respiratory effects of bolus IV isotonic crystalloid fluid therapy before pericardiocentesis in dogs with pericardial effusion. Design Prospective, randomized, nonblinded clinical trial (January 2021 to November 2022). Setting University teaching hospital. Animals Thirty dogs diagnosed with pericardial effusion. Interventions Dogs were randomized to receive a 10‐mL/kg IV bolus of compound sodium lactate (IV fluid bolus [IVFB] group) or no fluid bolus (no‐IVFB group) over 10 min before pericardiocentesis. Measurements and Main Results Cardiovascular parameters, respiratory rate, peripheral blood lactate concentration, and point‐of‐care ultrasound (POCUS) findings were assessed. Shock index (SI) was calculated as heart rate divided by systolic blood pressure. Measurements were recorded at four time points (T): baseline (T0), 15 min later (T1, after fluid bolus for the IVFB group), immediately after pericardiocentesis (T2), and 4 h after pericardiocentesis (T3). Significant decreases in SI were observed in the no‐IVFB group between T1 and T2 and between T1 and T3, and in the IVFB group between T1 and T3 ( p = 0.034, p = 0.003, and p = 0.027, respectively). No differences in SI were found between the groups when compared at the same time point. Administration of an IVFB did not result in adverse respiratory effects, as no dogs required supplemental oxygen by T3, and there were no differences in respiratory rate. The no‐IVFB group had a higher incidence of new B‐lines compared with the IVFB group (60% vs. 20%), but the median B‐line score was ≤1 at all POCUS sites at T0 and T3. Twenty‐four dogs survived to hospital discharge with no difference in survival between groups. Conclusions Administering an IVFB of 10 mL/kg isotonic crystalloid before pericardiocentesis in dogs with pericardial effusion did not alter SI. This dose appears to be safe, with no adverse respiratory effects seen. However, the current study was underpowered to detect a significant difference, and further studies are needed.