[Dorsal recumbency in dogs--a circulatory risk during surgical treatment?]

In this study, changes in hemodynamic, blood gas, and metabolic variables recorded during right lateral and dorsal recumbency in beagles anaesthetised with thiopental are presented. Other than reported in human beings, dorsal recumbency in these dogs resulted in an increase (33%) in heart rate, decrease (30%) in systolic, diastolic, and mean systemic arterial pressure, a decrease (17%) in systemic vascular resistance, and a decrease in both right (31%) and left (39%) ventricular work in comparison with lateral recumbency. Furthermore, mixed-venous PO2, oxygen saturation and respiratory quotient were lower in dorsal than in lateral recumbency while O2 consumption and lipolysis were increased in the former. The changes presented may have been caused by beta-adrenergic stimulation in dorsal recumbency. It needs to be studied if capillary perfusion can be maintained adequately during surgery in dorsal recumbency or if this predisposes to cardiovascular shock.