SESSION TYPE: Pediatric Critical Care
PRESENTED ON: Sunday, October 21, 2012 at 01:15 PM - 02:45 PM
PURPOSE: We hypothesize that the standard practice of taking an automated oscillometric blood pressure measurement on the lower leg of children and assume that it corresponds with the right arm’s reading is incorrect.
METHODS: Repeated simultaneous arm and ankle blood pressure measurements were taken on 64 children age 3 - 7, lying horizontally supine, using two calibrated automated oscillometric machines. Bland - Altman plots and conversion equations were obtained using the MethComp R statistical package.
RESULTS: 344 pairs of arm - ankle blood pressure measurements were made, with systolic/diastolic(SBP/DBP)blood pressure range of 83-144/29-105 and 74-154/34-101 for the arm and ankle. The mean ankle-arm difference in SBP and DBP were 8.7, 0.8,2.3 with limits of agreement (LOA) of -14 to 31, -16 to 18, -12 to 16. DBP showed a significant negative correlation between the ankle-arm pressure difference and the average. The conversion equations are: (1) SBP - arm = 4 + 0.9 ankle (95% p.i.: +/- 21), and (2) DBP - arm = -9.8 + 1.2 ankle ( +/- 18). The SBP and DBP standard deviations of the method x patient effect, the residual standard deviations for the arm and ankle readings were 7, 3.5, and 4.4, and 4.3, 4, and 4.3. The coefficient of repeatability for the SBP and DBP for arm/ankle measurements were: 11.6/13.8 and 13.6/14.2. Thirty-seven children had 2 sets of readings taken at least 15 minutes apart, and the percentage change over time in ankle readings were used to assess the trend in the arm’s readings. The mean ankle-arm difference in percentage change of SBP and DBP over time were -0.8 and 1.1 with a LOA of -22 to 21 and -39 to 41.
CONCLUSIONS: Ankle SBP are higher than arm SBP. Generally, a percentage change in ankle blood pressure, reflects a corresponding percentage change in the arm. But the device’s poor repeatability, results in such a high degree of inaccuracy that an ankle reading may not accurately reflect the arm’s reading, both on an absolute and relative basis.
CLINICAL IMPLICATIONS: Clinical judgement as to the true state of tissue perfusion is advised.
DISCLOSURE: The following authors have nothing to disclose: Tiong The, Jessica Butrico, Consolacion Solema
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