Cerebral arterial oxygen saturation measurements using a fiber-optic pulse oximeter.
BACKGROUND
A pilot investigation was undertaken to assess the performance of a novel fiber-optic cerebral pulse oximetry system. A fiber-optic probe designed to pass through the lumen of a cranial bolt of the type used to make intracranial pressure measurements was used to obtain optical reflectance signals directly from brain tissue.


METHODS
Short-duration measurements were made in six patients undergoing neurosurgery. These were followed by a longer duration measurement in a patient recovering from an intracerebral hematoma. Estimations of cerebral arterial oxygen saturation derived from a frequency domain-based algorithm are compared with simultaneous pulse oximetry (SpO2) and hemoximeter (SaO2) blood samples.


RESULTS
The short-duration measurements showed that reliable photoplethysmographic signals could be obtained from the brain tissue. In the long-duration study, the mean (±SD) difference between cerebral oxygen saturation (ScaO2) and finger SpO2 (in saturation units) was -7.47(±3.4)%. The mean (±SD) difference between ScaO2 and blood SaO2 was -7.37(±2.8)%.


CONCLUSIONS
This pilot study demonstrated that arterial oxygen saturation may be estimated from brain tissue via a fiber-optic pulse oximeter used in conjunction with a cranial bolt. Further studies are needed to confirm the clinical utility of the technique.
Phillips
J P
JP
School of Engineering and Mathematical Sciences, City University, London EC1V 0HB, UK. justin.phillips.1@city.ac.uk
Langford
R M
RM
Chang
S H
SH
Maney
K
K
Kyriacou
P A
PA
Jones
D P
DP
D000368:Aged; D001930:Brain Injuries / Q000503:physiopathology; D020202:Cerebral Hemorrhage, Traumatic / Q000097:blood / Q000175:diagnosis / Q000503:physiopathology; D004867:Equipment Design; D005260:Female; D005336:Fiber Optic Technology; D015600:Glasgow Coma Scale; D006801:Humans; D008991:Monitoring, Physiologic; D009493:Neurosurgery / Q000379:methods; D010092:Oximetry / Q000295:instrumentation / Q000379:methods*; D010100:Oxygen / Q000097:blood*; D010865:Pilot Projects; D020521:Stroke / Q000503:physiopathology
D010100:Oxygen
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