Increased intraabdominal pressure (IAP) during laparoscopy can reduce venous return, but changes in respiratory system mechanics and their effect in left cardiac function are not well documented. This study evaluated the effects of different IAPs on respiratory mechanics and cardiac function in 10 healthy nonpregnant adult Santa Ines ewes randomly submitted to a crossover study using different IAPs: 0 mm Hg (G1), 10 mm Hg (G2), 12 mmHg (G3), and 15 mmHg (G4). Animals were anesthetized and mechanically ventilated (V _T = 15 ml/kg; positive end‐expiratory pressure = 3 cmH₂O; FiO₂ = 1.0). Pneumoperitoneum was induced by Hasson's trocar cannula. Variables were measured at INITIAL (IAP, 0 mmHg) and FINAL time points for each IAP after 1 h. At FINAL, driving airway pressure (ΔP,_RS), and percentage fraction of dead space (Vd/Vt) were higher in G3 and G4 than G1 (p = 0.002, difference in means [MD] 4.60, 95% CI: 7.91–1.28, and p < 0.001, MD 5.4, 95% CI: 8.7–2.0; p = 0.016, MD −9.5, 95% CI: −17.9 to −1.2; and p = 0.027, MD −8.7, 95% CI: −17.1 to −0.4). The ejection fraction and fractional shortening were lower in G3 (p = 0.039, MD −11.38, 95% CI: −0.07−−22.68; p = 0.015, MD −13.05, 95% CI: −1.74−−24.36) and G4 (p = 0.039, MD −9.94, 95% CI: −0.07 to −19.80; p = 0.015, MD −11.43, 95%CI: −1.57 to −21.30, respectively) than G2. In G3, the maximum pulmonary flow velocity correlated negatively with ΔP,_RS (r = −0.740; p = 0.018), and Vd/Vt correlated positively with ΔP,_RS (r = 0.738, p = 0.046). At IAP of 12 and 15 mm Hg impaired respiratory system mechanics, reduced left cardiac function and no change in maximum pulmonary artery flow velocity were detected. Therefore, respiratory mechanics should be monitored as an interplay to reduce left cardiac function.

The high prevalence of exercise-induced pulmonary hemorrhage (EIPH) in athletic horses constitutes to be a challenge to the racing industry and a source of major concern to animal welfare. Both experimental and clinical evidence indicate that the use of autologous platelet-rich plasma (PRP) is a promising effector of repair in a variety of pulmonary conditions. The present study evaluated the effect of intrabronchial instillation of PRP on EIPH endoscopic scores from 37 Thoroughbred racehorses. Inclusion criteria were for animals to be EIPH-positive in, at least, two consecutive post-exercise endoscopic exams and to receive 250mg of furosemide IV four hours before racing. Animals were randomly assigned into 3 groups: placebo, control, and PRP instillation. All 37 Thoroughbred racehorses included had EIPH endoscopic scores pre- and post- treatment compared by statistical analysis. The bleeding score from the group receiving PRP was significantly lower than in the control and placebo groups. No adverse effects were observed in any animal during or after the experiment. It was possible to conclude that the intrabronchial instillation of autologous PRP was effective in reducing EIPH scores in racehorses receiving furosemide and that this bioproduct can be considered as a promising coadjuvant in controlling EIPH in athletic horses.