Monitoring brain tissue oxygen tension in brain-injured patients reveals hypoxic episodes in normal-appearing and in peri-focal tissue.
OBJECTIVE
We compared brain tissue oxygen tension (PtiO2) measured in peri-focal and in normal-appearing brain parenchyma on computerized tomography (CT) in patients following traumatic brain injury (TBI).


METHODS
Prospective observational study.


METHODS
Neurointensive care unit.


METHODS
Thirty-two consecutive TBI patients were subjected to PtiO2 monitoring.


METHODS
Peri-focal tissue was identified by the presence of a hypodense area of the contusion and/or within 1 cm from the core of the contusion. The position of the tip of the PtiO2 probe was assessed at follow-up CT scan.


RESULTS
Mean PtiO2 in the peri-contusional tissue was 19.7+/-2.1 mmHg and was lower than PtiO2 in normal-appearing tissue (25.5+/-1.5 mmHg, p < 0.05), despite a greater cerebral perfusion pressure (CPP) (73.7+/-2.3 mmHg vs. 67.4+/-1.4 mmHg, p < 0.05). We observed both in peri-focal tissue and in normal-appearing tissue episodes of brain hypoxia (PtiO2 < 20 mmHg for at least 10 min), whose median duration was longer in peri-focal tissue than in normal-appearing tissue (51% vs. 34% of monitoring time, p < 0.01). In peri-focal tissue, we observed a progressive PtiO2 increase from pathologic to normal values (p < 0.01).


CONCLUSIONS
Multiple episodes of brain hypoxia occurred over the first 5 days following severe TBI. PtiO2 was lower in peri-contusional tissue than in normal-appearing tissue. In peri-contusional tissue, a progressive increase of PtiO2 from pathologic to normal values was observed over time, suggestive of an improvement at microcirculatory level.
Longhi
Luca
L
University of Milano, Fondazione IRCCS, Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena,Neurosurgical Intensive Care Unit, Department of Anesthesia and Critical Care Medicine, Via Sforza n 35, 20100 Milan, Italy. lucalonghi@policlinico.mi.it
Pagan
Francesca
F
Valeriani
Valerio
V
Magnoni
Sandra
S
Zanier
Elisa R
ER
Conte
Valeria
V
Branca
Vincenzo
V
Stocchetti
Nino
N
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001930:Brain Injuries / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D006801:Humans; D020925:Hypoxia-Ischemia, Brain / Q000503:physiopathology*; D007558:Italy; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D010100:Oxygen / Q000378:metabolism*; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed
D010100:Oxygen