Abstract 170: Correlation of Thirst and Vasopressin to Central Hypovolemia in a Lower-Body Negative Pressure Model of Hemorrhagic Shock
BACKGROUND: Historically, it has been dogma that trauma patients who report severe thirst are at greater risk for hemorrhagic shock. Prior research conducted on human patients undergoing trauma resuscitation before to onset of shock displayed poor correlation between thirst perception and biochemical markers vasopressin and angiotensin.
OBJECTIVE: to study thirst and plasma vasopressin levels during reproducible progressive hypovolemia to determine whether correlation exists.
METHODS: Healthy volunteers aged 18 to 50 were subjected to progressive levels of lower body negative pressure resulting in central hypovolemia, using a previously validated model for simulation of hemorrhage.After baseline, negative pressures of negative 30, 60, 90 and 120 torr were applied until systolic blood pressure decreased below 80, onset of altered mental status or voluntary cessation. During each progressive phase, subjects were asked to quantify thirst via an assisted, zero-anchored Likert scale. plasma vasopressin levels were collected via peripheral phlebotomy at baseline, -30 and -60 torr, pre-syncope point, and after 10 minute recovery period.
RESULTS: Ten subjects were studied. All completed the algorithm, but one subject’s blood samples were unusable due to clotting.Average change in thirst perception and vasopressin levels between baseline and pre-syncope were: 1.9 (CI95 .6 to 3.2) and 3.45 (1.5 to 5.4) respectively. Average change in thirst and vasopressin between baseline and post-recovery were 1.1 (-.2 to 2.5) and 1.13 (.08 to 2.17) respe4ctively.
CONCLUSION: In subjects undergoing central hyopvolemia mimicking progressive hemorrhage to a point of pre-syncope, both thirst perception and plasma vasopressin levels increased in direct proportion. Both markers warrent further investigation for utility as field triage and evacuation prioritization adjuncts in mass-casualty and rural settings.
- © 2012 by American Heart Association, Inc.