Anesthesiology 1999; 91:985–90 © 1999 American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins, Inc. Correlation between Cerebral Oxygen Saturation Measured by Near-infrared Spectroscopy and Jugular Oxygen Saturation in Patients with Severe Closed Head Injury Aram Ter Minassian, M.D.,* Nicolas Poirier, M.D.,† Marc Pierrot, M.D.,‡ Philippe Menei, M.D.,§ Jean Claude Granry, M.D., Mauro Ursino, Ph.D.,# Laurent Beydon, M.D.** Background: Near-infrared spectroscopy has been used to monitor cerebral oxygen saturation during cerebral circulatory arrest and carotid clamping. However, its utility has not been demonstrated in more complex situations, such as in patients with head injuries. The authors tested this method during con- ditions that may alter the arteriovenous partition of cerebral blood in different ways. Methods: The authors compared changes in measured cere- bral oxygen saturation and other hemodynamic parameters, including jugular venous oxygen saturation, in nine patients with severe closed head injury during manipulation of arterial carbon dioxide partial pressure and after mean arterial pres- sure was altered by vasopressors. Results: The Bland and Altman representation of cerebral oxygen saturation versus jugular oxygen saturation showed a uniform scatter. Values for changing arterial carbon dioxide partial pressure were: bias  1.1%, 2 SD 21%, absolute value; and those for alterations in mean arterial pressure: bias  3.7%, 2 SD 24%, absolute value. However, a Bland and Altman plot of changes in cerebral oxygen saturation ver- sus changes in jugular oxygen saturation had a negative slope (alteration in arterial carbon dioxide partial pressure: bias  2.4%, 2 SD 17%, absolute value; alteration in mean arterial pressure: bias 4.9%, 2 SD 31%, absolute value). Regres- sion analysis showed that changes in cerebral oxygen satura- tion were positively correlated with changes in jugular venous oxygen saturation during the carbon dioxide challenge, whereas correlation was negative during the arterial pressure challenge. Conclusions: Cerebral oxygen saturation assessed by near- infrared spectroscopy does not adequately reflect changes in jugular venous oxygen saturation in patients with severe head injury. Changes in arteriovenous partitioning, infrared-spec- troscopy contamination by extracerebral signal, algorithm er- rors, and dissimilar tissue sampling may explain these findings. (Key words: Brain; hemodynamics; spectroscopy; transcranial Doppler.) NEAR-INFRARED spectroscopy (NIRS) is a method for con- tinuous, noninvasive monitoring of cerebral oxygen satura- tion (Sc O 2 ). Its accuracy depends on distinguishing the signal reflected by the brain from that reflected by other tissues (skin, muscle, bone). 1,2 Several studies have shown that when used in normal human subjects, NIRS responds rapidly to cerebral oxygen desaturation during marked ce- rebral hypoperfusion or systemic hypoxia. 3–5 However, because severe hypotension (e.g., circulatory arrest) influ- ences both cerebral and extracerebral compartments, such studies do not validate the technique or at least do not prove its value in more complex situations. For example, NIRS detects only a fraction of the pathologic events iden- tified by parallel multimodal monitoring in human head injury. 6 Moreover, when NIRS is used in an intensive care setting, changes in cerebral blood flow (CBF) or vascular This article is featured in “This Month in Anesthesiology.” Please see this issue of ANESTHESIOLOGY, page 5A.  * Staff Anesthesiologist, Re ´animation chirurgicale, Centre Hospitalier Universitaire Larrey. † Senior Resident in Anesthesiology, Re ´animation chirurgicale, Cen- tre Hospitalier Universitaire Larrey. ‡ Resident in Anesthesiology, Re ´animation chirurgicale, Centre Hos- pitalier Universitaire Larrey. § Staff Neurosurgeon, Service de Neurochirurgie, Centre Hospitalier Universitaire Larrey.  Professor and Head of Department, Re ´animation chirurgicale, Cen- tre Hospitalier Universitaire Larrey. # Associate Professor, Dipartimento di elettronica, informatica e sistemistica, Universita degli studi di Bologna. ** Associate Professor, Re ´animation chirurgicale, Centre Hospitalier Universitaire Larrey. Received from Centre Hospitalier Universitaire Larrey, Angers, France; and Universita degli studi di Bologna, Bologna, Italy. Submitted for publi- cation July 1, 1998. Accepted for publication June 3, 1999. Support was provided solely from institutional and/or departmental sources. Address reprint requests to Dr. Ter Minassian: De ´partement d’Anesthe ´sie, Centre Hospitalier Universitaire Larrey, 49033 Angers Cedex, France. Address electronic mail to: lBeydon.angers@invivo.edu 985 Anesthesiology, V 91, No 4, Oct 1999 Downloaded from http://pubs.asahq.org/anesthesiology/article-pdf/91/4/985/397201/0000542-199910000-00018.pdf by guest on 06 November 2021