Intravenous formalin for treatment of haemorrhage in horses

Abstract

SummaryThere is limited information in the literature regarding the clinical use of formalin for the treatment of haemorrhage in horses. This uncontrolled retrospective study summarises 11 cases that were treated with intravenous formalin at the Veterinary Health Center at Kansas State University from 2009 to 2019. The objective of this study was to describe signalment, clinical and laboratory findings, treatment and outcome of horses treated with intravenous formalin for potentially life‐threatening haemorrhagic conditions. This study does not attempt to prove efficacy of intravenous formalin, but rather to report its clinical use and the associated details of those cases. Horses ranged in age from 2 to 23 years old. There were nine Quarter Horses, one Thoroughbred and one Appaloosa. Treated conditions included haemoabdomen (4/11), uterine haemorrhage (1/11), epistaxis (3/11), haemorrhage secondary to a mandibular laceration (2/11) and haemothorax (1/11). The most utilised dose was 0.476% formalin (50 mL 10% neutral buffered formalin diluted in 1 L of isotonic fluid). Some horses were also treated with aminocaproic acid, Yunnan Baiyao, whole blood transfusions and surgery. Ten out of the 11 horses survived to discharge with one horse reported by the owner to have died 2 weeks later of an unknown cause.