Stress-hemoconcentration: plasma volume changes or splenic contraction? A Reply to Engan and Schagatay

Splenic denervation worsens lipopolysaccharide-induced hypotension, hemoconcentration, and hypovolemia.

During lipopolysaccharide (LPS)-induced endotoxemia, increased intrasplenic fluid efflux contributes to a reduction in plasma volume. We hypothesized that splenic sympathetic nerve activity (SSNA), which increases during endotoxemia, limits intrasplenic fluid efflux. We reasoned that splenic denervation would exaggerate LPS-induced intrasplenic fluid efflux and worsen the hypotension, hemoconce...

Exercise induced hemoconcentration following spleen contraction in subjects with COPD

Background: The blood-boosting spleen contraction represents a potential protective response to hypoxia by raising the blood gas storage capacity. Human spleen contraction has been observed during exercise, apnea and simulated altitude resulting in ejection of stored red blood cells into circulation. High-altitude exposure has been shown to increase spleen contraction suggesting that long-term ...

Challenges in Controlling for the Effects of Hemoconcentration Reply

Hormonal and plasma volume changes after presyncope.

BACKGROUND Aim of this study was to test the hypothesis that after presyncope, some blood hormone pools increase while others decrease. MATERIALS AND METHODS In twelve healthy male adults, we determined plasma volume changes with plasma mass densitometry and hormone levels. The following were compared: supine rest, presyncope and 20-min post-presyncopal supine rest. We determined plasma renin...

Comparison of Stress-Hemoconcentration Correction Techniques for Stress-Induced Coagulation

When examining stress effects on coagulation, arithmetic correction is typically used to adjust for concomitant hemoconcentration but may be inappropriate for coagulation activity assays. We examined a new physiologically relevant method of correcting for stress-hemoconcentration. Blood was drawn from healthy men (N = 40) during baseline, mental stress, and recovery, and factor VII activity (FV...