title: Direct measurement of capillary blood pressure in the human lip.
abstract: In this study, we developed and tested a new procedure for measuring microcirculatory blood pressures above heart level in humans. Capillary and postcapillary venule blood pressures were measured directly in 13 human subjects by use of the servo-nulling micropressure technique adapted for micropuncture of lip capillaries. Pressure waveforms were recorded in 40 separate capillary vessels and 14 separate postcapillary venules over periods ranging from 5 to 64 s. Localization and determination of capillary and postcapillary vessels were ascertained anatomically before pressure measurements. Capillary pressure was 33.2 +/- 1.5 (SE) mmHg in lips of subjects seated upright. Repeated micropunctures of the same vessel gave an average coefficient of variation of 0.072. Postcapillary venule pressure was 18.9 +/- 1.6 mmHg. This procedure produces a direct and reproducible means of measuring microvascular blood pressures in a vascular bed above heart level in humans.
authors.affiliation: Life Science Division, National Aeronautics and Space Administration-Ames Research Center, Moffett Field, California 94035-1000.
authors.forename: S E
authors.initials: SE
authors.lastname: Parazynski
authors.forename: B J
authors.initials: BJ
authors.lastname: Tucker
authors.forename: M
authors.initials: M
authors.lastname: Aratow
authors.forename: A
authors.initials: A
authors.lastname: Crenshaw
authors.forename: A R
authors.initials: AR
authors.lastname: Hargens
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D001794:Blood Pressure / Q000502:physiology*; D001795:Blood Pressure Determination / Q000295:instrumentation*; D002196:Capillaries / Q000502:physiology; D003681:Dehydration / Q000503:physiopathology; D004487:Edema / Q000503:physiopathology; D005260:Female; D006801:Humans; D008046:Lip / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D011187:Posture / Q000502:physiology; D012039:Regional Blood Flow / Q000502:physiology; D012044:Regression Analysis; D012881:Skin Temperature / Q000502:physiology