Journal of clinical monitoring and computing
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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
Response time of the Opti-Q continuous cardiac output pulmonary artery catheter in the urgent mode to a step change in cardiac output.
This study was conducted to determine the response time of the Opti-Q continuous cardiac output (CCO) device to a step change in cardiac. ⋯ Continuous cardiac output measurement was as accurate as those made by standard bolus thermodilution. The average response time to acute changes in cardiac output was approximately 1.5 minutes or ten times faster than previously reported systems. Response time is independent of animal mass, shunt volume and the direction of cardiac output perturbations.
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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%.