Invasive and noninvasive assessment of cerebral oxygenation in patients with severe traumatic brain injury.
OBJECTIVE
The aim of this study is to investigate the relationship between invasive brain tissue oxygen pressure (PbrO(2)) and noninvasive regional transcranial oxygen saturation (rSO(2)) in 22 stable patients with severe traumatic brain injury (TBI) during a 16 h period.


METHODS
This was a prospective, observational study carried out in the Neurocritical Care Unit of a level 1 trauma center in a teaching hospital. A total of 41,809 paired records for neuromonitoring variables were analyzed and compared.


RESULTS
A direct and independent correlation between rSO(2) and PbrO(2) was confirmed through adjusted [beta coefficient and (95% confidence interval, CI) = 0.36 (0.35-0.37)] and logistic [PbrO(2) >or=15 mmHg, as a dependent variable; adjusted odds ratio (AOR) and (95% CI) = 1.11 (1.10-1.12)] regression analyses. A receiver-operating characteristic (ROC) curve demonstrated that rSO(2) had low accuracy for detecting moderate (PbrO(2) <or=15 mmHg) intracerebral hypoxia [area under curve (AUC) = 0.62], with the likelihood ratio for a positive test (LR+) = 1.2 for an optimal cutoff of rSO(2) <or=70%. In contrast, the ROC analysis showed that rSO(2) was moderately accurate for detecting severe (PbrO(2) <or=12 mmHg) intracerebral hypoxemia (AUC = 0.82; LR+ = 5.3) for an optimal cutoff of rSO(2) <or=60%.


CONCLUSIONS
In patients with severe TBI, PbrO(2) and rSO(2) were directly and significantly related. Severe intracerebral hypoxia was better detected by rSO(2) than was moderate intracerebral hypoxia. However, the diagnostic accuracy of rSO(2) was limited, and this measure should not be considered a substitute for routine PbrO(2) monitoring.
Leal-Noval
Santiago R
SR
Neuro Critical Care Division, Hospital Universitario Virgen del Rocío, Seville, Spain. srleal@telefonica.net
Cayuela
Aurelio
A
Arellano-Orden
Victoria
V
Marín-Caballos
Antonio
A
Padilla
Vicente
V
Ferrándiz-Millón
Carmen
C
Corcia
Yael
Y
García-Alfaro
Claudio
C
Amaya-Villar
Rosario
R
Murillo-Cabezas
Francisco
F
D000293:Adolescent; D000328:Adult; D001921:Brain / Q000098:blood supply*; D020520:Brain Infarction / Q000503:physiopathology; D001930:Brain Injuries / Q000097:blood / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology; D006801:Humans; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods*; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption; D011446:Prospective Studies; D014193:Trauma Centers; D015599:Trauma Severity Indices; D055815:Young Adult
D010100:Oxygen