Limits of Agreement of Calf, Ankle and Arm Non-Invasive Blood Pressure Measurement in Nigerian Adult Volunteers

Abstract

Background: Incidents like upper limb injuries and burns make compulsory non-invasive blood pressure (NIBP) measurement challenging.
Objective:To compare the efficacy of calf and ankle NIBPto standard arm NIBP.
Patients and Methods: Simultaneously, NIBP at upper arm, calf and ankle were measured for 140 volunteers in the supine position. Three measurements were taken at 5 minutes interval and the mean calculated. . Limits of agreement were determined for their mean differences. Incidence and severity of pain at the cuff inflation site was measured using numerical rating scale.
Results: Mean age was 30.36 ± 7.72 years. Mean calf (132.38 ± 21.53 mmHg) and ankle (119.00 ± 13.03 mmHg) SBP were significantly higher than mean arm SBP (114.15 ± 10.41 mmHg ) (p= 0.0001). Mean arm DBP (68.05 ± 7.62 mmHg) was comparable to mean calf DBP(68.41 ± 11.18 mmHg) (p = 0.6180). Mean ankle MAP(82.15 ± 8.66 mmHg) was significantly lower than mean arm MAP (83.42 ± 7.76 mmHg) (p = 0.0130). Only the Limits of agreement of the arm-ankle MAP(-10.43 to +12.97 mmHg) was in the clinically acceptable range (± 15 mmHg) Pain occurred in 82.1% of volunteers at the arm compared to 92.1% at the calf (p =0.0001) and 80.7% at the ankle (p=0.096).
Conclusion: The calf was not a suitable alternative site to upper arm NIBP. However, the ankle MAP can replace arm MAPin unusual situations where the arm is not available. More volunteers felt pain at the calf than at the upper arm and ankle.

Keywords: NIBPmeasurement, sites, arm, ankle, calf, limits of agreement.