IMPACT OF OXYGEN SUPPLEMENTATION ON ANESTHETIC RECOVERY IN HORSES UNDERGOING LAPAROTOMY FOR COLIC SYNDROME

• Grant number: 25/00878-3
• Support Opportunities: Scholarships in Brazil - Master
• Start date: January 01, 2026
• End date: May 31, 2027
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Clinics and Surgery
• Principal Investigator: Adriano Bonfim Carregaro
• Grantee: Alline Morgana Silva Leite
• Host Institution: Faculdade de Zootecnia e Engenharia de Alimentos (FZEA). Universidade de São Paulo (USP). Pirassununga , SP, Brazil

Abstract

Colic syndrome or acute abdomen is the main emergency seen in the clinical-surgical routineof horses and hypoxemia is one of the most frequent complications in the perioperative period,significantly affecting recovery. The aim of this study is to determine an effective method ofoxygen supplementation directed towards maintaining normoxia in horses recovering fromlaparotomy for colic syndrome. Horses will be sedated with 10 - 15 µg/kg of detomidine, andanesthesia will be induced with 2 mg/kg of ketamine combined with 0.1 mg/kg of diazepamand maintained under general anesthesia with isoflurane. Mechanical ventilation will beperformed to maintain expired carbon dioxide concentrations (ETCO2) < 60 mmHg and partialpressures of oxygen in arterial blood (PaO2) > 250 mmHg. The anesthetic protocol will beadjusted as necessary. In recovery, three randomly assigned groups (n = 8) will be implemented:horses devoid of oxygen supplementation but with an endotracheal tube (Endotracheal Tube)in place; horses supplemented with oxygen through a cannula (15 L/min) inserted in the lumenof the endotracheal tube (O2-Tracheal); horses supplemented with oxygen through a demandvalve (O2-Valve), with peak pressure set at 40 mmHg. Arterial blood samples will be collectedat specific time points throughout recovery: at the preanesthetic period; one hour following theonset of anesthesia; upon arrival at the recovery room (Rec-0); after 15 minutes (Rec-15) and30 (Rec-30) minutes after the onset of oxygen supplementation; and at the end of recovery(quadrupedal position). Hydrogen potential (pH), partial pressure of oxygen (PaO2), partialpressure of carbon dioxide (PaCO2), arterial oxygen saturation (SaO2), base excess (BE),bicarbonate concentration (HCO3-), electrolyte (Na+, K+, Cland Ca2+), glucose (Glu),hematocrit (Hct) and hemoglobin (Hb) values will be determined. The quality of recovery willbe analyzed using a species-specific score. It is expected that O2 supplementation viaintratracheal or demand valve increases PaO2 values and prevents hypoxemia, as well asimproves the quality of recovery in horses. (AU)