[Reflex changes in efferent sympathetic nerve activities of visceral organs during PEEP loading in anesthetized dogs].

Objective: To study the effects of PEEP 0.98 kPa (1 kPa = 10.2 cmH2O) on the sympathetic nerve activities of visceral organs in anesthetized dogs with intact neuraxis or with vagotomy.
Methods: Renal (RNA), cardiac (CNA), hepatic (HNA) and adrenal gland (AdNA) sympathetic nerve activities were recorded. Mean blood pressure (MBP), central venous pressure (CVP), left atrial pressure (LAP) and airway pressure (AWP) were also measured.
Results: AdNA significantly decreased, but RNA, CNA and HNA had a tendency toward decrease during PEEP loading in the intact dogs. However, vagotomy reversed the changes in all nerve activities in the intact dogs. CVP, LAP and AWP significantly increased, while MBP significantly decreased during PEEP loading.
Conclusion: The results indicated that PEEP loading caused sympathoinhibition in the adrenal gland, kidney, heart and liver, which were mediated by activation of cardiopulmonary baroreceptor.