Method of deflection corrected tonometry with phantom vessel experiments.

Background: The Continuous Non-Invasive measurement of arterial Blood Pressure [CNIBP] is possible via the method of arterial tonometry and the arterial volume clamp methods. Arterial tonometry successfully measures continuous arterial pressure but requires large vessel deformation and a highly miniaturized pressure sensor to obtain a direct calibration of pressure. A properly designed tonometer is capable of achieving pressure accuracy of less than 5% error at the radial artery.

Tonometric arterial pulse sensor with noise cancellation.

Arterial tonometry provides for the continuous and noninvasive recording of the arterial pressure waveform. However, tonometers are affected by motion artifact that degrades the signal. An arterial tonometer was constructed using two piezoelectric transducers centered within a solid base.

Measurement and monitoring of electrocardiogram belt tension in premature infants for assessment of respiratory function.

Background: Monitoring of the electrocardiogram (ECG) in premature infants with conventional adhesive-backed electrodes can harm their sensitive skin. Use of an electrode belt prevents skin irritation, but the effect of belt pressure on respiratory function is unknown. A strain gauge sensor is described which measures applied belt tension.

Cardiac force and muscle shortening in regional ischemia: asynchronization and possible uncoupling.

Acute myocardial ischemia affects both cardiac muscle force development and shortening in the affected regions. The exact mechanisms are unclear. We investigated myocardial function during ischemia and reperfusion both experimentally and with a muscle fiber model.

Experimental evaluation of the elastic determinants of myocardial function in vivo.

Shortening of myocardial fibers occurs following force development in those fibers. The extent, speed and timing of shortening are determined by kinetics and extent of force. However, shortening is also influenced by the elastance/viscosity of the muscle tissue, because that determines the coupling between force and shortening.