Journal of clinical monitoring and computing
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J Clin Monit Comput · Dec 1999
The relationship between modified pulse wave transit time and cardiovascular changes in isoflurane anesthetized dogs.
To clarify the relationship between blood pressure and pulse wave transit time at the peripheral artery from the R wave of the electrocardiogram (m-PWTT), the effects of cardiovascular interventions on this relationship was evaluated. ⋯ Change in m-PWTT is a good parameter to predict blood pressure changes, although the absolute blood pressure value cannot be obtained.
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J Clin Monit Comput · Dec 1999
Autoregulation in a simulator-based educational model of intracranial physiology.
To implement a realistic autoregulation mechanism to enhance an existing educational brain model that displays in real-time the cerebral metabolic rate (CMRO2), cerebral blood flow (CBF), cerebral blood volume (CBV), intracranial pressure (ICP), and cerebral perfusion pressure (CPP). ⋯ The autoregulated brain model, with incorporated CO2 responsivity and a variable oxygen extraction, automatically produces changes in CVR, CBF, CBV, and ICP consistent with literature reports, when run concurrently with a METI full-scale patient simulator (Medical Education Technologies, Inc., Sarasota, Florida). Once the model is enhanced to include herniation, vasospasm, and drug effects, its utility will be expanded beyond demonstrating only basic neuroanesthesia concepts.
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J Clin Monit Comput · Dec 1999
The influence of left lateral position on cardiac output changes after head up tilt measured by impedance cardiography.
The value of the impedance cardiography (IC) method for measuring cardiac output (CO) with the subject in the left lateral position has not yet been established. We compared the CO after a 30 degrees head-up tilt with the subjects in the supine and left lateral position. ⋯ When using the IC method of SV measurement, the absolute value of the CI changes when moving from the supine to lateral positions. It is not clear whether this change is physiologic or an artifact of the measurement technique. However, changes in CI in response to a 30 degree head up tilt are the same in either position. We conclude that changes in CI can be measured with the IC method in the lateral position.
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J Clin Monit Comput · Dec 1999
Hemodilution does not alter the aortic-to-femoral arterial pressure difference in dogs.
Distal arterial pressure normally differs from aortic pressure. This difference is modified by changes of vascular resistance. Hemodilution, due to decreased viscosity, decreases vascular resistance. Therefore, the difference between aortic and distal arterial pressures could be altered as well. We investigated whether acute hemodilution affected this difference in dogs. ⋯ Acute hemodilution did not alter the aortic-to-distal arterial pressure difference in dogs.