Monitoring brain tissue oxygen tension in brain-injured patients reveals hypoxic episodes in normal-appearing and in peri-focal tissue.
ABSTRACT 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).
Prospective observational study.
Neurointensive care unit.
Thirty-two consecutive TBI patients were subjected to PtiO2 monitoring.
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.
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).
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.
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ABSTRACT: This manuscript summarises the consensus on neuromonitoring in neuro-intensive care promoted and organised by the Neuro-Intensive Care and Emergency Medicine (NICEM) Section of the European Society of Intensive Care Medicine (ESICM). It is expected that continuous monitoring using multi-modal techniques will help to overcome the limitations of each individual method and will provide a better diagnosis. More specific treatment can then be applied; however, it remains to be determined which combination of parameters is optimal. The questions discussed and addressed in this manuscript are: (1) Who should have ICP monitoring and for how long? (2) What ICP technologies are available and what are their relative advantages/disadvantages? (3) Should CPP monitoring and autoregulation testing be used? (4) When should brain tissue oxygen tension (PbrO(2)) be monitored? (5) Should structurally normal or abnormal tissue be monitored with PbrO(2)? (6) Should microdialysis be considered in complex cases? It is hoped that this document will prove useful to clinicians working in NICU and also to those developing specialist NICU services within their hospital practice.Intensive Care Medicine 05/2008; 34(8):1362-70. · 5.40 Impact Factor
Article: Invasive and noninvasive assessment of cerebral oxygenation in patients with severe traumatic brain injury.[show abstract] [hide abstract]
ABSTRACT: 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. 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. 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%. 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.European Journal of Intensive Care Medicine 08/2010; 36(8):1309-17. · 5.17 Impact Factor
Article: Year in review in Intensive Care Medicine, 2007. I. Experimental studies. Clinical studies: brain injury and neurology, renal failure and endocrinology.Intensive Care Medicine 03/2008; 34(2):229-42. · 5.40 Impact Factor