title: Skin microvascular flow during hypobaric exposure with and without a mechanical counter-pressure space suit glove.
abstract: BACKGROUND
  Current space suits are rigid, gas-pressurized shells that protect astronauts from the vacuum of space. A tight elastic garment or mechanical-counter-pressure (MCP) suit generates pressure by compression and may have several advantages over current space suit technology. In this study, we investigated local microcirculatory effects produced with and without a prototype MCP glove.
  
  
  METHODS
  The right hand of eight normal volunteers was studied at normal ambient pressure and during exposure to -50, -100 and -150 mm Hg with and without the MCP glove. Measurements included the pressure against the hand, skin microvascular flow, temperature on the dorsum of the hand, and middle finger girth.
  
  
  RESULTS
  Without the glove, skin microvascular flow and finger girth significantly increased with negative pressure, and the skin temperature decreased compared with the control condition. The MCP glove generated approximately 200 mm Hg at the skin surface; all measured values remained at control levels during exposure to negative pressure.
  
  
  CONCLUSIONS
  Without the glove, skin microvascular flow and finger girth increased with negative pressure, probably due to a blood shift toward the hand. The elastic compression of the material of the MCP glove generated pressure on the hand similar to that in current gas-pressurized space suit gloves. The MCP glove prevented the apparent blood shift and thus maintained baseline values of the measured variables despite exposure of the hand to negative pressure.
authors.affiliation: University of California, San Diego, Department of Orthopaedics, 92103, USA.
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Tanaka
authors.forename: James
authors.initials: J
authors.lastname: Waldie
authors.forename: Gregory C
authors.initials: GC
authors.lastname: Steinbach
authors.forename: Paul
authors.initials: P
authors.lastname: Webb
authors.forename: Dietmar
authors.initials: D
authors.lastname: Tourbier
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Knudsen
authors.forename: Christine W
authors.initials: CW
authors.lastname: Jarvis
authors.forename: Alan R
authors.initials: AR
authors.lastname: Hargens
mesh_terms: D000328:Adult; D001274:Atmospheric Pressure; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D001831:Body Temperature / Q000502:physiology; D004867:Equipment Design; D018478:Extravehicular Activity; D006225:Hand / Q000098:blood supply; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D008833:Microcirculation; D012867:Skin / Q000098:blood supply*; D019442:Space Suits; D018544:Weightlessness Countermeasures