CEREBRAL OXYGENATION MONITORING BY NEAR-INFRARED SPECTROSCOPY IS NOT CLINICALLY USEFUL IN PATIENTS WITH SEVERE CLOSED-HEAD INJURY - A COMPARISON WITH JUGULAR VENOUS BULB OXIMETRY

Objective: To compare continuous jugular venous bulb oximetry and cere bral near-infrared spectroscopy in patients with severe closed head in jury. Design: A prospective observational study. Setting: Intensive ca re unit of a major teaching hospital. Patients: Adults (n = 10) with s evere closed-head injury (Glasgow Coma Scale score of less than or equ al to 8). Interventions: None. Measurements and Main Results: Jugular venous bulb oximetry, cerebral near-infrared spectroscopy, and cerebra l perfusion pressure were measured continuously, A total of 3,691 pair ed measurements of near infrared spectroscopy and jugular venous bulb oximetry were analysed, Poor correlation (r(2) =.04) between paired me asurements and wide limits of agreement (-13% to +21%) were demonstrat ed. The mean difference between measurements was +/-4% and the standar d deviation of the mean difference was +/-8.69%. The data were subsequ ently grouped according to three clinically significant subgroups of j ugular venous bulb oxygen saturation reflecting low (<55%), normal (55 % to 75%) and high (>75%) saturation values, Poor correlation and wide limits of agreement between the two methods of measurement were obser ved in all groups, Values recorded by near-infrared spectroscopy did n ot significantly change between the groups, and 14 clinically signific ant episodes of jugular venous bulb desaturation were not detected by near-infrared spectroscopy. Conclusions: Tissue oxygen saturation dete rmined by near-infrared spectroscopy does not reflect significant chan ges in cerebral oxygenation detected by the global measurement of jugu lar venous bulb oximetry, This finding may be explained by inadequate signal detection and inaccuracies in the algorithm used to filter out extracranial components. Until these technical difficulties are addres sed, near infrared spectroscopy, as measured by the machine assessed i n this study, cannot be routinely recommended for assessment of cerebr al oxygenation in patients with acute head injury.