Search PubMed⌕ Search

Biomedical subjects

W F Barker

Publications and source records attributed to W F Barker.

78 records · Page 5Linked to original sources
PubMedDate not supplied

Concurrent validity studies of blood pressure instrumentation. The Philadelphia Blood Pressure Project.

There is increasing evidence that blood pressure (BP) screening during adolescence may detect early evidence of hypertensive disease. Choice of instrumentation becomes important to maximize the accuracy and interpretive value of several serial readings. We therefore conducted two studies of adolescents, comparing auscultatory (Baumanometer and Random-zero), ultrasonic (Arteriosonde 1216), and infrasonic (Physiometrics SR-2) devices. These instruments were compared serially (Study 1) for older adolescents (n = 48). The Baumanometer, Arteriosonde 1216, and Physiometrics SR-2 were compared both serially and simultaneously (Study 2) for younger and older adolescents (n = 24). In both studies, the order of device presentation was completely counterbalanced. In Study 1, reliability estimates were high (r greater than 0.65), with the exception of the Arteriosonde 1216 diastolic readings, and the Physiometrics SR-2 yielded significantly lower mean diastolic BP readings than the other devices. Diastolic Phase V readings taken with the Random-zero were significantly higher when the Random-zero was presented at the end of the sequence of instrument presentation. This order of presentation effect is probably attributable to the need for overinflation when using the Random-zero device and may cause an overestimation of diastolic BP in the young. In Study 2, again the Arteriosonde 1216 did not perform reliably in recording diastolic BP. Further, the Physiometrics SR-2 device, although reliable, yielded diastolic readings significantly lower (p less than 0.001) than diastolic Phase IV readings taken both serially and simultaneously.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Blood pressure, growth and maturation from childhood through adolescence. Mixed longitudinal analyses of the Philadelphia Blood Pressure Project.

This paper presents data on the extent to which blood pressure (BP) and growth status at 7 years of age are associated with BP, growth, and maturity status during adolescence. Two samples of black adolescents, namely, a representative sample (n = 562) stratified by sex and age (11 to 15 years) and a sample (n = 256) with supine BP over one standard deviation above the mean at 7 years of age (High BP7), were selected from the Philadelphia Collaborative Perinatal Project (CPP) population and followed longitudinally for 3 years. When the subjects reached adolescence we again measured supine blood pressure, height, weight, and skeletal maturity. Analyses of the data collected at 7 years of age by the CPP indicated that weight and height are highly significantly associated with systolic blood pressure (SBP) and diastolic blood pressure (DBP) respectively. Accordingly, the SBP, DBP, weights, and heights of the representative sample at age 7 were divided into percentile groupings (< 15%, 15%-85%, > 85%). Using mixed longitudinal analyses during adolescence, we found that mean SBP tracked in males through age 15 and in females through age 13 based on the percentile groupings of SBP, height, and weight. Moreover, the weight percentile groupings provided the best discrimination of SBP at these ages. Skeletal age also tracked throughout early adolescence using these percentile groupings of 7-year heights and weights. In females only, diastolic phase 4 (DBP4) during adolescence was significantly associated with 7-year height percentile groupings. In comparing the representative and the High BP7 samples at each chronological age for BP, height, weight, and skeletal age at adolescence (ages 12 to 17 years), it was found that the High BP7 sample was, on the average, taller and heavier at age 7 and throughout early adolescence. At age 17 in males, however, there were no significant differences in BP, growth, or maturity status. In females, SBP of the High BP7 sample remained significantly higher, and there was a tendency for them to remain heavier through age 17. Hence BP variation is so closely associated with growth and maturation that these factors must be taken into account when assessing BP in childhood and adolescence.

Adolescent↗
PubMedDate not supplied

Chiropractic biophysics lateral cervical film analysis reliability.

OBJECTIVE: To determine the degree to which the geometric line drawings used in Chiropractic Biophysics Technique (CBP) on lateral cervical radiographs are reliable. DESIGN: A blind, delayed repeated measures design was used. Three examiners were presented radiographs in random order. All identifying marks were removed prior to each examiner's individual marking and measurement. Each examiner was blinded as to how the previous examiners marked and measured the radiographs. SETTING: Primary care private chiropractic clinic. PATIENTS PARTICIPANTS: Sixty-five subject films were provided from the patient records of a primary care private chiropractic clinic. The 65 radiographs qualified for inclusion in the study based on two criteria: C1 through C7 had to be clearly visible, and there had to be no identifying artifacts. MAIN OUTCOME MEASURES: Anterior head translation in millimeters, atlas plane to horizontal, Ruth Jackson's cervical stress lines, and five relative rotation angles for C2-C3, C3-C4, C4-C5, C5-C6, C6-C7. Inter- and intrareliability of the three examiners were statistically analyzed. RESULTS: Intraexaminer for a) C1 to horizontal reliability was .98-.99 with confidence intervals of .96-.99, b) absolute rotation angle from C2 to C7 reliability was .82-.95 with confidence intervals of .80-.99, c) anterior head translation [+Sz] reliability was .86-.99, with confidence intervals of .74-.99, d) relative rotation angle reliability ranges were (C2-C3) .99, and (C3-C4) .98-.99, (C4-C5) .88-.99, (C5-C6) .80-.99, and (C6-C7) .94-.98. Interexaminer reliabilities across examiners ranged from a) Winer:.89-.99 and b) Bartko: .72-.96. CONCLUSIONS: The reliabilities for intra- and interexaminer were all greater than .70, indicating that these measurements in CBP technique would be considered accurate enough to provide measurements for future clinical studies. The data indicated that the C6-C7 relative rotation angle was the least reliable measurement. This might be due to the very small angles found at this level.

Analysis of Variance↗