title: Sonographic inferior vena cava measurements to assess hydration status in college football players during preseason camp.
abstract: OBJECTIVE
  The purpose of this study was to determine whether sonographic measurement of the inferior vena cava (IVC) in college football players during preseason camp is a reliable way to detect and monitor dehydration. Our primary hypothesis was that IVC diameter measurements, the postpractice caval index, and expiratory diameter were significantly related to percent weight loss after a preseason football practice.
  
  
  METHODS
  A prospective cohort sample of Division I intercollegiate football players in preseason training camp was recruited before practice. All football players on the active roster who were at least 18 years of age were eligible to participate in the study. Sonographic IVC measurements were obtained in the long axis using either the subcostal or subxiphoid approach during inspiration and expiration both before and after an approximately 3-hour practice with moderate to high levels of exertion at high ambient temperatures. Player weights were recorded in the locker room before and after practice.
  
  
  RESULTS
  A total of 27 prepractice and postpractice sonographic measurements were obtained. The postpractice expiratory IVC diameter was significantly related to percent weight loss after practice (R(2) = 0.153; P = .042), with the IVC diameter being significantly inversely correlated with percent weight loss; the regression coefficient was -1.07 (95% confidence interval, -2.09 to -0.04). There was no statistically significant relationship between percent weight loss and the postpractice caval index; the regression coefficient was 0.245 (95% confidence interval, -0.10 to 0.59; R(2) = 0.078; P = .16).
  
  
  CONCLUSIONS
  The postpractice expiratory IVC diameter was significantly related to percent weight loss after practice, whereas the caval index was not found to correlate with weight loss.
authors.affiliation: University of Arizona, Tucson, Arizona USA. awaterbrook@aemrc.arizona.edu.
authors.forename: Anna L
authors.initials: AL
authors.lastname: Waterbrook
authors.affiliation: University of Arizona, Tucson, Arizona USA.
authors.forename: Amish
authors.initials: A
authors.lastname: Shah
authors.affiliation: University of Arizona, Tucson, Arizona USA.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Jannicky
authors.affiliation: University of Arizona, Tucson, Arizona USA.
authors.forename: Uwe
authors.initials: U
authors.lastname: Stolz
authors.affiliation: University of Arizona, Tucson, Arizona USA.
authors.forename: Randy P
authors.initials: RP
authors.lastname: Cohen
authors.affiliation: University of Arizona, Tucson, Arizona USA.
authors.forename: Austin
authors.initials: A
authors.lastname: Gross
authors.affiliation: University of Arizona, Tucson, Arizona USA.
authors.forename: Srikar
authors.initials: S
authors.lastname: Adhikari
mesh_terms: D000293:Adolescent; D003681:Dehydration / Q000000981:diagnostic imaging* / Q000209:etiology*; D005538:Football; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D064797:Physical Conditioning, Human / Q000009:adverse effects*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000379:methods*; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging*; D015431:Weight Loss; D055815:Young Adult
keywords: caval index; dehydration; expiration diameter; football; inferior vena cava; point-of-care ultrasound; sonography