Blood pressure changes in dogs with babesiosis

Systemic arterial blood pressures were measured in 30 dogs with acute babes iosis, 10 each with mild uncomplicated, severe uncomplicated and complicate d disease. Ten healthy dogs were used as controls. Hypotension was defined as more than 3 standard deviations below the control mean. Normal mean pres sures (+/-SD) were: systolic arterial pressure 151 (+/-11) mm Hg, diastolic arterial pressure 89 (+/-8) mm Hg and mean arterial pressure 107 (+/-10) m m Hg. Hypotension was the most frequent abnormality, and increased striking ly in incidence as disease severity increased, with 5/10 dogs in the compli cated group being hypotensive for systolic, diastolic and mean arterial pre ssures, compared with 2/10 in the severe uncomplicated group and 0/10 in th e mild uncomplicated group. Systolic, diastolic and mean arterial pressures in the complicated group and severe uncomplicated group, and systolic pres sure in the mild uncomplicated group, were significantly lower than in the controls. There were no significant relationships between arterial pressure s and age, pulse rate, respiratory rate, temperature, mucous membrane colou r or haematocrit. There was a significant negative correlation between arte rial pressures and white cell and immature neutrophil counts. Arterial pres sures differed significantly between dogs that were clinically collapsed an d those that were not, but not between survivors and non-survivors. Pulse p ressure (systolic - diastolic) was low in 7/10 complicated, 1/10 mild uncom plicated, and 1/10 severe uncomplicated cases, and differed significantly b etween the complicated and control groups. The high incidence of hypotensio n in clinically severe babesiosis has important implications for therapy.