title: The influence of the AGSM, PBG, and anti-G suit inflation on thoracic hemodynamics during +Gz in swine.
abstract: With the advent of pressure breathing for +Gz (head-to-foot inertial loading) protection (PBG) and the development of improved extended coverage anti-G suits (ECGS) it has become important to expand our knowledge of the cardiopulmonary physiologic interrelationships of pressure breathing, anti-G suit protection, and the anti-G straining maneuver (AGSM).  Although high levels of pressure breathing have been previously investigated, there was continuing concern within the aeromedical community regarding the introduction of COMBAT EDGE, a PBG system.  Some of the concerns were:  barotrauma, pneumothorax, air embolism, excessive transmural vascular pressures, possible cardiac valvular damage, and possible overdilation of the right ventricle from a surge in venous return following +Gz.  This study describes the experimental preparation and results of a hemodynamic investigation to address some of these concerns using chronically instrumented miniature swine (MS).
authors.affiliation: Crew Technology Division, Armstrong Laboratory, Brooks AFB, TX, USA.
authors.forename: J W
authors.initials: JW
authors.lastname: Burns
authors.forename: J W
authors.initials: JW
authors.lastname: Fanton
authors.forename: J L
authors.initials: JL
authors.lastname: Robinson
mesh_terms: D000818:Animals; D002496:Central Venous Pressure / Q000502:physiology; D002498:Centrifugation; D005260:Female; D005676:Gravity Suits; D006439:Hemodynamics / Q000502:physiology; D018471:Hypergravity; D011175:Positive-Pressure Respiration / Q000009:adverse effects*; D011187:Posture / Q000502:physiology; D012119:Respiration / Q000502:physiology*; D012149:Restraint, Physical; D013552:Swine; D013556:Swine, Miniature / Q000502:physiology*; D013895:Thoracic Arteries / Q000502:physiology; D013909:Thorax / Q000502:physiology*; D016277:Ventricular Function, Left / Q000502:physiology; D017725:Ventricular Pressure / Q000502:physiology