CKiD participants have casual BP measurements obtained in the right arm by auscultation at study entry (baseline), then annually thereafter. All participating sites have been provided the same aneroid sphygmomanometer (Mabis MedicKit 5, Mabis Healthcare, Waukegan, IL) by the CKiD Clinical Coordinating Centers (CCC's). The CCC's also provide standardized training and certification in the auscultatory BP measurement protocol described below to all study personnel responsible for casual BP measurement. Recertification in auscultatory BP measurement technique and calibration of each center's aneroid device takes place annually.
At each study visit, prior to BP determination, arm circumference is measured (in centimeters) with a plastic measuring tape at the midpoint of the upper arm between the amicron and olecranon and a cuff is then selected so that the length of the cuff bladder is equal to 80-100% of the arm circumference6 (link). Following cuff selection, the peak inflation pressure is determined by inflating the cuff to 60 mmHg and then gradually continuing to inflate in increments of 10 mmHg until the radial pulse is no longer felt – thereby determining the pulse obliteration pressure. An additional 30 mmHg is added to this value and recorded as the peak inflation pressure. The cuff is then inflated to this value for all BP measurements at that study visit.
After 5 minutes of rest, BP measurement begins. Participants are instructed to refrain from caffeine intake, smoking, and exercise at least one half hour prior to and until completion of BP measurement. They are also instructed to refrain from playing video games, using a cell phone, or other activities that may affect BP until all measurements are obtained. First, pulse is measured by palpation of the radial artery. Then three BP measurements at 30-second intervals are obtained by auscultation of the brachial artery, using the first Korotkoff sound for systolic BP (SBP) and the fifth Korotkoff sound for diastolic BP (DBP). The average of the 3 BP measurements is recorded as the participant's BP for the study visit. Participants' BP's so obtained at the baseline visit are included in the present study.
At each study visit, prior to BP determination, arm circumference is measured (in centimeters) with a plastic measuring tape at the midpoint of the upper arm between the amicron and olecranon and a cuff is then selected so that the length of the cuff bladder is equal to 80-100% of the arm circumference6 (link). Following cuff selection, the peak inflation pressure is determined by inflating the cuff to 60 mmHg and then gradually continuing to inflate in increments of 10 mmHg until the radial pulse is no longer felt – thereby determining the pulse obliteration pressure. An additional 30 mmHg is added to this value and recorded as the peak inflation pressure. The cuff is then inflated to this value for all BP measurements at that study visit.
After 5 minutes of rest, BP measurement begins. Participants are instructed to refrain from caffeine intake, smoking, and exercise at least one half hour prior to and until completion of BP measurement. They are also instructed to refrain from playing video games, using a cell phone, or other activities that may affect BP until all measurements are obtained. First, pulse is measured by palpation of the radial artery. Then three BP measurements at 30-second intervals are obtained by auscultation of the brachial artery, using the first Korotkoff sound for systolic BP (SBP) and the fifth Korotkoff sound for diastolic BP (DBP). The average of the 3 BP measurements is recorded as the participant's BP for the study visit. Participants' BP's so obtained at the baseline visit are included in the present study.
