Limited fluid volume resuscitation (LFVR) in severe shock unresponsive to initial fluid challenge: A pilot study in 10 cats

Objective: To evaluate the effect of limited fluid volume resuscitation (LFVR) administration in catswith severe shock that was unresponsive to initial conventional resuscitation (CR) with isotoniccrystalloids. Study design: Clinical pilot study. Animals: Ten client-owned cats with non-cardiogenic shock, unresponsive to CR. Methods: After an initial ineffective CR with isotonic crystalloids (15-20 mL kg-1 in 15 minutes), LFVR was started. The animals were randomly assigned to one of two treatments: hypertonic saline alone (group HTS) or HTS and hydroxyethyl starch (HES) (group HTS/HES). A first bolus of HTS (2 mL kg-1) was administered to both groups, immediately followed by HES (2 mL kg-1) to group HTS/HES over 5-10 minutes and vital signs were re-evaluated. Additional boluses were administered, every 5-10 minutes,until stabilization (vital parameters, such as temperature, heart rate, respiratory frequency, quality of the pulse and sensorium within the physiological ranges). The time until stabilization (minutes), the volume of HTS and colloid administered and the effect of LFVR on vital parameters were determined. Results: A mean±standard deviation (range) volume of 3±2 (2-6) mL kg-1of hypertonic saline in group HTS and 4±2 (2-6) mL kg-1 of both hypertonic and colloidal solutions in group HTS/HES was administered. In six cats (60%), a single bolus of HTS alone (group HTS;n=3/4) or in combination with HES (group HTS/HES;n=3/6) was sufficient for stabilization. In the remaining four cases (40%), a second bolus was required. Stabilization occurred in 33±13 minutes (15-60minutes). Of the 10 cats, six had a positive outcome (6-24 months follow-up) and the others died during hospitalization.Conclusions and clinical relevance: LFVR appears to be an efficacious treatment for feline shock and may be an alternative therapy for cats unresponsive to CR. Larger cross-sectional and prospective studies are needed to confirm these findings.