Spc 350

The algorithms described in this section were evaluated using previously reported data (21) . The following is a brief summary of the protocol. Six Yorkshire swine (30-34kg) were studied. The experimental protocol conformed to the Guide for the Care and Use of Laboratory Animals and was approved by the MIT Committee on Animal Care. The animals were pre-anesthetized with intramuscular telazol, xylazine, and atropine prior to endotracheal intubation. The swine were then maintained in a deep plane of anesthesia using inhaled anesthetic isoflurane (0.5-4 %), a mixture of oxygen and ambient air.
Positive-pressure mechanical ventilation at a rate of 10-15 breathes/min, and a tidal volume of 10 ml/kg was employed.
Central ABP (CAP) was measured from the thoracic aorta using a micromanometer-tipped catheter (SPC 350, Millar Instruments, Houston, TX). Femoral ABP (FAP) and radial ABP (RAP) were measured using external fluid-filled pressure transducer (TSD104A, Biopac Systems, Santa Barbara, CA). The

We used a tonometer probe (model SPC-350, Millar Instruments, Inc, Houston) to register and digitize right common carotid artery pressure waveforms, 19, 20 (link) which were then ensemble averaged and calibrated to mean arterial pressure (diastolic BP plus 1/3 pulse pressure) and diastolic BP 21 using a custom-designed software on a commercial software package (Matlab, version 4.2 and 7.0, The MathWorks, Inc). The calibrated carotid pressure waveforms were decomposed to calculate the forward wave amplitude (Pf) and backward wave amplitude (Pb), based on the triangulation method (details of the method is provided in the online-only Data Supplement). 22 (link) Carotid-femoral PWV was measured by recording tonometric pulse waves along with a simultaneous ECG at the right common carotid artery and right femoral artery sequentially. 16 (link)