What does this research mean for the field?

During incremental venous pressure elevation in humans, capillary pressure rises less than venous pressure for changes greater than 20 mmHg, and capillary pulse pressure amplitude significantly declines both during and after elevation, mirroring changes in the pre- to postcapillary resistance ratio. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

May 15, 1995Open Access

Capillary pressure during and after incremental venous pressure elevation in man.

Structured PICO

Does incremental venous pressure elevation alter capillary pressure and capillary pulse pressure amplitude in healthy volunteers?

Population

7 healthy volunteers

Intervention

Incremental venous pressure elevation via inflation of a sphygmomanometer cuff around the upper arm

Comparator

Baseline (before cuff inflation) and post-cuff release

Outcome

Capillary pressure (Pc) and capillary pulse pressure amplitude (CPPA)surrogate

Incremental venous pressure elevation leads to a less than proportional increase in capillary pressure and a reduction in capillary pulse pressure amplitude, which persists shortly after pressure release.

Abstract

The relationship between capillary pressure and venous pressure was investigated during incremental venous pressure elevation in seven healthy volunteers. Pressure was measured simultaneously at the apex of finger nailfold capillaries and in the dorsal vein of the ipsilateral hand. Elevation of venous pressure was accomplished by inflation of a sphygmomanometer cuff around the upper arm. 2. As venous pressure rose, apical capillary pressure (Pc) approached venous pressure (Pv). For changes in Pv greater than 20 mmHg, the increment in Pc was invariably less than the increment in Pv. 3. Above a cuff pressure of 20 mmHg, capillary pulse pressure amplitude (CPPA) tended to decline. At 50 mmHg cuff pressure, CPPA was lower than at baseline for all subjects. At baseline, CPPA was 4.2 +/- 2.0 mmHg (mean +/- S.D.) and at 50 mmHg it was 2.3 +/- 1.1 mmHg (P = 0.02). 4. In the period between 1 and 6 min following cuff release, both Pc and CPPA were lower than at baseline. (At baseline, Pc was 16.1 +/- 2.3 mmHg and following cuff release it was 11.2 +/- 1.5 mmHg (P = 0.02). At baseline, CPPA was 4.2 +/- 2.0 mmHg and following cuff release it was 1.8 +/- 1.1 mmHg (P = 0.03).) 5. Estimated changes in the ratio of pre- to postcapillary resistance (Ra/Rv), using arterial blood pressure (Pa) measured in the contralateral arm, and taking (Pa-Pc)/(Pc-Pv) to approximate to Ra/Rv, closely mirrored changes in CPPA.(ABSTRACT TRUNCATED AT 250 WORDS)

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