title: A questionable association of stroke volume and arterial pulse pressure under gravitational stress.
abstract: BACKGROUND
  The purpose of this study was to examine individual stroke volume-pulse pressure (PP) relationships in healthy young men and women.
  
  
  METHODS
  Sixteen healthy men and women were assessed at baseline and during four 12-minute stages of progressive lower body negative pressure (LBNP) at -15, -30, -45, and -60 mm Hg.
  
  
  RESULTS
  Throughout staged LBNP, systolic blood pressure (105 ± 7.8 vs. 103 ± 8.3 mm Hg) and mean arterial pressure were not statistically different (81 ± 5.6 vs. 83 ± 5.9 mm Hg). There was also a significant increase in diastolic blood pressure (69 ± 5.3 vs. 72 ± 5.9 mm Hg) and heart rate (63 ± 8.3 vs. 86 ± 14.2 bpm) as well as a decrease in PP (37 ± 5.7 vs. 31 ± 7.0 mm Hg) and stroke volume (80 ± 17.0 vs. 26.6 ± 10.0 mL). There was a strong positive relationship for LBNP versus stroke volume (r2 = 0.99), PP (r2 = 0.96), and heart rate (r2 = -0.92), as well as for stroke volume versus PP (r2 = 0.98) and stroke volume versus heart rate (r = -0.94). Substantial intersubject variability in the stroke volume and PP correlations were presented. Strong, significant correlations were only displayed for 38% of the participants, while heart rate and stroke volume was strongly associated in 63% of these individuals.
  
  
  CONCLUSIONS
  This work highlights the limitations of using PP when assessing trauma patients because of large interindividual differences.
authors.affiliation: Department of Medicine, School of Kinesiology, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Anita T
authors.initials: AT
authors.lastname: Cote
authors.forename: Aaron A
authors.initials: AA
authors.lastname: Phillips
authors.forename: Shannon S D
authors.initials: SS
authors.lastname: Bredin
authors.forename: Darren E R
authors.initials: DE
authors.lastname: Warburton
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000502:physiology*; D001795:Blood Pressure Determination; D015716:Electrocardiography, Ambulatory; D005260:Female; D018470:Gravity, Altered / Q000009:adverse effects*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D020896:Hypovolemia / Q000503:physiopathology*; D008150:Lower Body Negative Pressure; D008297:Male; D012016:Reference Values; D013312:Stress, Physiological / Q000502:physiology*; D013318:Stroke Volume / Q000502:physiology*; D011795:Surveys and Questionnaires; D055815:Young Adult