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Distensibility of the common carotid and carotid sinus during lower body negative pressure
Author(s) -
Hodges Gary J,
Norton Katelyn N,
Chia Justin,
Zuj Kathryn A,
Shoemaker J Kevin
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.957.5
Subject(s) - supine position , medicine , baroreceptor , baroreflex , carotid sinus , lower body , cardiology , orthostatic vital signs , blood pressure , anesthesia , heart rate
Changes in common carotid distensibility (CCD) do not correlate well with reductions in baroreflex sensitivity (BRS). This might be due to assessment of distensibility in the common carotid (CC) rather than the carotid sinus (CS), the location of the baroreceptors. To test this, two studies were performed. In Part 1 ( n =10), pulsatile pressure (tonometry) and diameter (Ultrasound) of the CC and CS were assessed on both sides of the neck. This study characterized the bilateral similarities of these vascular segments and confirmed that simultaneous diameter and pressure measures from contralateral CC and CS could be used for distensibility calculations. In Part 2 ( n =3), changes in the CCD and CS distensibility (CSD) measured during supine rest and with an orthostatic stress of ‐40 mmHg lower body negative pressure (LBNP). Bilateral comparisons of the CCD (R 6.81±1.39, L 6.17±0.59 units; P = 0.62) or the CSD (R 9.56±2.25, L 9.74±2.88 units; P = 0.97) were not different. Pulse pressures in the CC were 43±5 mmHg supine and 46±1 in LBNP and in the CS were 50±13 mmHg while supine and 28±7 mmHg during LBNP. Nonetheless, CSD was reduced from supine (9.3±0.75 units) during LBNP (3.79±1.51 units; P = 0.04) whereas CCD was unaffected (7.49±3.37 supine vs. 7.79±1.65 units in LBNP; P = 0.92). LBNP has a larger effect on distensibility of the CS than the CC. Supported by Canadian Diabetes Association and Canadian Institutes of Health Research.