Objective: Compare cardiac index (CI) and oxygen delivery index (DO2I) in conscious, critically ill dogs to control dogs; evaluate the association of CI and DO2I with outcome.
Design: Prospective non-randomized clinical study.
Setting: Veterinary teaching hospital.
Animals: Eighteen client-owned dogs with systemic inflammatory response syndrome (SIRS) and 8 healthy control dogs.
Measurements and Main Results: CI of dogs with SIRS was measured using lithium dilution at times 0, 4, 8, 16, and 24 hours. Data collected included physical exam, arterial blood gas (ABG) and hemoximetry. CI of control dogs was measured 3 times with 1 measurement of ABG. Mean CI ± SE in SIRS patients was 3.32 ± 0.95 L/min/m2; lower than controls at 4.18 ± 0.22 L/min/m2 (P<0.001). Mean DO2I ± SE in SIRS patients was 412.91 ± 156.67 mL O2/min/m2; lower than controls at 785.24 ± 45.99 mL O2/min/m2 (P<0.001). There was no difference in CI (P=0.49) or DO2I (P=0.51) for dogs that survived to discharge versus those that did not. There was no difference in mean CI (P=0.97) or DO2I (P=0.50) of survivors versus non-survivors for 28-day survival. Survivors had lower blood glucose (P=0.03) and serum lactate concentrations (P=0.04) than non-survivors.
Conclusions: CI and DO2I in conscious dogs with SIRS were lower than control dogs, which differs from theories that dogs with SIRS are in a high cardiac output state. CI and DO2I were not significantly different between survivors and non-survivors. Similar to previous studies, lactate and glucose concentrations of survivors were lower than non-survivors.