Kwan H. Chan

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Middle cerebral artery blood flow velocity and jugular bulb venous oxygen saturation (SJO2) were measured by transcranial Doppler (TCD) ultrasonography and continuous venous oximetry, respectively, in 41 severely brain-injured patients. The purpose of the study was to examine the relationships between TCD flow velocity, SJO2, and alterations in blood(More)
Transcranial doppler measurements of blood flow velocity in the middle cerebral artery were made during treatment of raised intracranial pressure (ICP) in 22 patients with severe brain injury. Twenty patients also had continuous measurement of arterial and jugular bulb venous oxygen saturation (SJO2). The transcranial Doppler parameters studied included(More)
Using transcranial doppler ultrasonography, cerebral blood flow velocity was measured daily from both middle cerebral arteries in 121 patients who had suffered minor (n = 55), moderate (n = 16), or severe (n = 50) brain injury. Serial computed tomographic scans were performed to identify noncontusion-related infarction (NCI). Cerebral perfusion pressure was(More)
Raised intracranial pressure (ICP) occurs at some time in 50-75% of severely head injured patients. Measurement of ICP alone is not sufficient. Arterial pressure must also be monitored: the important physiological variable is cerebral perfusion pressure. Detailed analysis of the ICP recording yields valuable information on the nature and cause of ICP, with(More)
BACKGROUND Brain dysfunction is common in patients with advanced liver disease; it is often manifested as hepatic encephalopathy, but its cause is not clearly understood. METHODOLOGY Intracranial blood flow velocity parameters, including peak systolic velocity, end diastolic velocity and mean velocity of both middle cerebral arteries were measured by(More)
Patients scheduled to undergo tonsillectomy were administered 500 mg oral azithromycin as two 250 mg capsules given 12 h apart. Between 9 h and one week after the second dose, tonsil samples were taken during surgery and assayed for azithromycin. Mean concentrations in tonsillar tissue, 12 and 24 h after the second of the two 250 mg doses given 12 h apart,(More)
Many developing economies use tax holidays to attract foreign investment by providing a limited period of tax exemptions and reductions for qualified investors. This paper investigates the effect of tax holidays on foreign investors’ tax noncompliance behavior in China’s developing economy. We measure noncompliance in terms of tax audit adjustments the(More)
To successfully match the treatment to the cause for raised intracranial pressure (ICP) after a severe head injury, it is important to know the underlying mechanism at a given moment for the raised pressure. In particular, it is important to distinguish between active cerebral vasodilation, indicating functional autoregulation, and a passive vascular(More)
Therapeutic agents for reducing raised intracranial pressure (ICP) may do so at the expense of reduced mean arterial pressure (MAP). As a consequence, cerebral perfusion pressure (CPP) = (MAP - ICP) may not improve. It is unknown whether the level of MAP alters cerebral blood flow (CBF) when MAP and ICP change in parallel so that CPP remains constant. This(More)