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Abstract
There is a need for objective, diaphragm-specific respiratory function measurements applicable to clinical settings. PURPOSE: To establish an improved measurement of respiratory function via assessment of diaphragm endurance.
METHODS: 20 healthy subjects, highly active (HA) (n=10) or inactive (IN) (n=10), were tested using electrical stimulation (5 Hz, 5-minutes) on one occasion. Stimulation electrodes were placed on one phrenic nerve, and a current producing a vigorous contraction was used. An accelerometer collecting at 400Hz was placed on the abdomen. An endurance index (EI) was calculated from the acceleration values at 2 (EI2) and 5 minutes (EI5). RESULTS: EI2 of IN and HA were 68.8±16.3% and 92.8±8.7% respectively (p=0.001). EI5 of IN and HA were 62.6±12.4% and 85.7±13.6% respectively (p=0.001). The correlation of EI2 and EI5 was 0.588. CONCLUSIONS: Highly active subjects had higher diaphragm endurance index values than inactive subjects, supporting the use of the test to evaluate respiratory function.
METHODS: 20 healthy subjects, highly active (HA) (n=10) or inactive (IN) (n=10), were tested using electrical stimulation (5 Hz, 5-minutes) on one occasion. Stimulation electrodes were placed on one phrenic nerve, and a current producing a vigorous contraction was used. An accelerometer collecting at 400Hz was placed on the abdomen. An endurance index (EI) was calculated from the acceleration values at 2 (EI2) and 5 minutes (EI5). RESULTS: EI2 of IN and HA were 68.8±16.3% and 92.8±8.7% respectively (p=0.001). EI5 of IN and HA were 62.6±12.4% and 85.7±13.6% respectively (p=0.001). The correlation of EI2 and EI5 was 0.588. CONCLUSIONS: Highly active subjects had higher diaphragm endurance index values than inactive subjects, supporting the use of the test to evaluate respiratory function.