Autonomic nervous function in upper gastrointestinal endoscopy: a prospective randomized comparison between transnasal and oral procedures
Transnasal esophagogastroduodenoscopy (EGD) using an ultrathin endoscope is less stressful to the cardiovascular system with less elevation of systolic blood pressure (BP) than oral procedures. autonomic nervous responses were determined employing power spectral analysis (PSA) of heart-rate variations on electrocardiogram
