Background: Arterial blood flow (BF) to all abdominal-pelvic organs (AP) shows potential for an indicator of comprehensive splanchnic organ circulation (reservoir of blood supply for redistribution) in cardiovascular disease, hepato-gastrointestinal disease or hemodynamic disorders. Our previous assessment of splanchnic hemodynamics, as magnitude of BFAP [measuring by subtracting BF in both femoral arteries (FAs) from the upper abdominal aorta (Ao) above the celiac trunk] using Doppler ultrasound, was reported as the relationship between Ao and FAs, day-to-day variability and response to exercise. For accurate determination of BFAP, it is important to consider the various factors that potentially influence BFAP. However, little information exists regarding the influence of respiration (interplay between inspiration and expiration) and posture on BFAP.
Material/Methods: Ten healthy males were evaluated in sitting/supine positions following a 12 hr fast. Magnitude of BFAP was determined as measurement of Ao and FAs hemodynamics (blood velocity and vessel diameter) using pulsed Doppler with spectral analysis during spontaneous 4-sec inspiration/4-sec expiration phases.
Results: BF/blood velocity in the Ao and FAs showed significant lower in inspiration than expiration. BFAP showed a significant (P<0.005) reduction of ~20% in inspiratory phase (sitting, 2213±222 ml/min; supine, 2059±215 ml/min) compared with expiratory phase (sitting, 2765±303 ml/min; supine, 2539±253 ml/min), with no difference between sitting and supine.
Conclusions: Respiratory-related to alterations in BFAP were observed. It may be speculated that changes in intra-abdominal pressure during breathing (thoracic-abdominal movement) is possibly reflecting transient changes in blood velocity in the Ao and FAs. Respiratory effects should be taken into account for evaluation of BFAP.

Keywords: Regional Blood Flow - physiology, Perfusion, Posture - physiology, Pelvis - blood supply, Blood Flow Velocity - physiology, Arteries - physiology, Abdomen - blood supply, Respiration, Supine Position, young adult