Journal of clinical monitoring and computing
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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.
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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
Comparative Study Clinical TrialA comparison of pulse oximetry and near infrared spectroscopy (NIRS) in the detection of hypoxaemia occurring with pauses in nasal airflow in neonates.
The aim of this study was to compare the ability of NIRS and pulse oximetry to detect changes in cerebral oxygenation occurring in response to a pause in nasal airflow (PNA). ⋯ We conclude that both techniques are sensitive to changes in oxygenation during PNA. Small changes in cerebral Hbdiff and arterial SpO2 do not always correlate for physiological reasons. A change in Hbdiff of >0.3 micromol 100 g brain(-1) is likely to be physiologically significant and is associated with a change in SpO2 of 12%.
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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.