Suction effusion fluid from skin and constituent analysis: new candidate for interstitial fluid

The authors analyzed the constituents of effuse transcutaneous fluid, labeled suction effusion fluid (SEF), and monitored its glucose concentration during glucose loading in rabbits (Japan White, female) under pentobarbital anesthesia. The SEF was sampled by suctioning corneal layer-stripped skin at 400 mmHg absolute pressure. The SEF proved to have nearly the same concentrations as serum for lower-molecular-weight substances such as glucose, creatinine, and urea nitrogens, but not for higher-molecular-weight substances such as serum proteins. The SEF protein concentration was one-fourth that of serum protein. Proteins > 100 kDa molecular mass were barely detectable in the SEF. Monitoring of SEF glucose change every 10 min during intravenous glucose loading was successfully accomplished, and SEF glucose concentration followed blood glucose concentration with a 10-min delay. The SEF was thought to consist of interstitial fluid and/or effuse fluid from small vessels in subcutaneous tissue.