Application of laser Doppler flowmetry in neurosurgery.
Experience with LDF has indicated that intraoperative estimation of cerebral blood flow can be very useful and that long-term recordings of cortical perfusion pressure are possible. The disadvantage of LDF is that measurements are extremely local and that the units of measurements are arbitrary. Moreover, the reliability of the technique depends to a large extent on probe position and on the avoidance of movement artifact. The disadvantages are, however, compensated by an excellent dynamic resolution with ultra-short time responses to sudden fluctuations in cerebral perfusion pressure. The high temporal resolution of LDF provides the opportunity to detect hemodynamic events and to monitor the microcirculatory effects of treatment that alters cerebral perfusion pressure in patients with raised intracranial pressure. At no point in the near future is LDF going to supercede continuous recording of intracranial pressure and mean arterial blood pressure and, hence, cerebral perfusion pressure. Rather, we envision LDF becoming an integral part of a multimodal patient monitoring system whereby time trends of monitored variables are combined with calculated variables to provide continuous assessment of cerebral hemodynamic and compensatory reserves.
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Staten Island University Hospital, New York, USA.
DiResta
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D006801:Humans; D017078:Laser-Doppler Flowmetry / Q000295:instrumentation / Q000379:methods; D009493:Neurosurgery