TY - JOUR
T1 - Changes in pulse character and mental status are late responses to central hypovolemia
AU - Ryan, Kathy L.
AU - Batchinsky, Andriy
AU - McManus, John G.
AU - Rickards, Caroline A.
AU - Convertino, Victor A.
N1 - Funding Information:
This research was supported by funding from the United States Army Medical Research and Materiel Command Combat Casualty Research Program.
PY - 2008/4
Y1 - 2008/4
N2 - Objective. Manual assessment of radial arterial pulse character remains an important determinant of physiological status in military and civilian casualties. This study hypothesized that changes in radial pulse character and mental status (presyncopal symptoms) in humans occur only during the later stages of progressive reductions in central blood volume in close association with systolic blood pressure (SBP). Methods. Pulse character (i.e., normal, weak, absent), estimated stroke volume (SV), SBP, and diastolic blood pressure were measured continuously during baseline supine rest and during progressive reductions of central blood volume to cardiovascular collapse with application of lower body negative pressure (LBNP) in 19 healthy human volunteer subjects. Results. LBNP resulted in a progressive reduction in SV. At early stages of LBNP, both radial pulse character and SBP were well-maintained. Although both radial pulse character and SBP decreased with subsequent increases in LBNP, these changes occurred only after an approximate 55% reduction in SV and were associated with the onset of presyncopal symptoms. Changes in mental status did not occur until the point of cardiovascular collapse. Conclusions. In this model of progressive central hypovolemia secondary to application of LBNP in humans, radial pulse character score decreased in concert and was highly correlated with decreases in SBP. In support of our hypothesis, changes in pulse character, SBP, and mental status occurred only after significant reductions in SV, suggesting that these standard vital signs may not be early indicators of central hypovolemia.
AB - Objective. Manual assessment of radial arterial pulse character remains an important determinant of physiological status in military and civilian casualties. This study hypothesized that changes in radial pulse character and mental status (presyncopal symptoms) in humans occur only during the later stages of progressive reductions in central blood volume in close association with systolic blood pressure (SBP). Methods. Pulse character (i.e., normal, weak, absent), estimated stroke volume (SV), SBP, and diastolic blood pressure were measured continuously during baseline supine rest and during progressive reductions of central blood volume to cardiovascular collapse with application of lower body negative pressure (LBNP) in 19 healthy human volunteer subjects. Results. LBNP resulted in a progressive reduction in SV. At early stages of LBNP, both radial pulse character and SBP were well-maintained. Although both radial pulse character and SBP decreased with subsequent increases in LBNP, these changes occurred only after an approximate 55% reduction in SV and were associated with the onset of presyncopal symptoms. Changes in mental status did not occur until the point of cardiovascular collapse. Conclusions. In this model of progressive central hypovolemia secondary to application of LBNP in humans, radial pulse character score decreased in concert and was highly correlated with decreases in SBP. In support of our hypothesis, changes in pulse character, SBP, and mental status occurred only after significant reductions in SV, suggesting that these standard vital signs may not be early indicators of central hypovolemia.
KW - Cardiovascular collapse
KW - Hemorrhagic shock
KW - Lower body negative pressure
UR - http://www.scopus.com/inward/record.url?scp=41649120549&partnerID=8YFLogxK
U2 - 10.1080/10903120801907562
DO - 10.1080/10903120801907562
M3 - Article
C2 - 18379916
AN - SCOPUS:41649120549
SN - 1090-3127
VL - 12
SP - 192
EP - 198
JO - Prehospital Emergency Care
JF - Prehospital Emergency Care
IS - 2
ER -