Ionized Hypocalcemia in Critically Ill Dogs

Background: Ionized hypocalcemia (iHCa) is a common electrolyte disturbance in critically ill people, especially those with sepsis. The cause of the iHCa is not entirely understood and is likely multifactorial. Critically ill people with iHCa have longer hospital stays and higher mortality rates compared to people with normocalcemia. There are no published clinical studies evaluating the incidence and impact of iHCa in critically ill dogs.
Hypothesis: iHCa occurs in critically ill dogs, is more prevalent in dogs with systemic inflammatory response syndrome (SIRS) or sepsis, and is associated with longer hospital stays and higher mortality.
Animals: One hundred and forty-one client-owned dogs admitted to a companion animal intensive care unit (ICU) in a veterinary teaching hospital.
Methods: Prospective observational study of sequentially enrolled dogs. Blood was collected and analyzed within an hour of admission from all dogs presented to the ICU that met study inclusion criteria.
Results: The incidence of iHCa (iCa < 1.11 mmol/L) was 16%. The presence of iHCa was associated with longer ICU ( P = .038) and hospital ( P = .012) stays but not with decreased survival ( P = .60). Dogs with sepsis as defined by ≥3 SIRS criteria and a positive culture were more likely to have iHCa ( P = .050).
Conclusions and Clinical Relevance: In dogs not previously treated with fluids or blood products intravenously, the finding of iHCa upon admission to the ICU predicted a longer duration of ICU and hospital stay. Septic dogs with positive cultures were more likely to have iHCa.