Journal of neurosurgery
-
Journal of neurosurgery · Jan 2002
Cerebral tissue PO2 and SjvO2 changes during moderate hyperventilation in patients with severe traumatic brain injury.
The aim of this study was to investigate the effects of moderate hyperventilation on intracranial pressure (ICP), jugular venous oxygen saturation ([SjvO2], an index of global cerebral perfusion), and brain tissue PO2 (an index of local cerebral perfusion). ⋯ Ninety-four tests consisting of 20-minute periods of moderate hyperventilation (27-32 mm Hg) were performed on different days in 36 patients with severe traumatic brain injury (Glasgow Coma Scale score < or = 8). Moderate hyperventilation resulted in a significant reduction in average ICP, but in seven tests performed in five patients it was ineffective. The response of SjvO2 and brain tissue PO2 to CO2 changes was widely variable and unpredictable. After 20 minutes of moderate hyperventilation in most tests (79.8%), both SjvO2 and brain tissue PO2 values remained above the lower limits of normality (50% and 10 mm Hg, respectively). In contrast, in 15 tests performed in six patients (16.6% of the studied population) brain tissue PO2 decreased below 10 mm Hg although the corresponding SjvO2 values were greater than 50%. The reduction of brain tissue PO2 below 10 mm Hg was favored by the low prehyperventilation values (10 tests), higher CO2 reactivity, and, possibly, by lower prehyperventilation values of cerebral perfusion pressure. In five of those 15 tests, the prehyperventilation values of SjvO2 were greater than 70%, a condition of relative hyperemia. The SjvO2 decreased below 50% in four tests; the corresponding brain tissue PO2 values were less than 10 mm Hg in three of those tests, whereas in the fourth, the jugular venous O2 desaturation was not detected by brain tissue PO2. The analysis of the simultaneous relative changes (prehyperventilation - posthyperventilation) of SjvO2 and brain tissue PO2 showed that in most tests (75.5%) there was a reduction of both SjvO2 and brain tissue PO2. In two tests moderate hyperventilation resulted in an increase of both SjvO2 and brain tissue PO2. In the remaining 17 tests a redistribution of the cerebral blood flow was observed, leading to changes in SjvO2 and brain tissue PO2 in opposite directions. CCONCLUSIONS. Hyperventilation, even if moderate, can frequently result in harmful local reductions of cerebral perfusion that cannot be detected by assessing SjvO2. Therefore, hyperventilation should be used with caution and should not be considered safe. This study confirms that SjvO2 and brain tissue PO2 are two parameters that provide complementary information on brain oxygenation that is useful to reduce the risk of secondary damage. Changes in SjvO2 and brain tissue PO2 in opposite directions indicate that data obtained from brain tissue PO2 monitoring cannot be extrapolated to evaluate the global cerebral perfusion.
-
Journal of neurosurgery · Jan 2002
Effect of apolipoprotein E genotype on hematoma volume after trauma.
The apolipoprotein E-epsilon4 (APOE-epsilon4) allele is associated with poor outcome after head injury and spontaneous intracerebral hemorrhage (SICH). The aims of this study were to determine if patients in whom one or more APOE-epsilon4 alleles are present are more likely to sustain intracranial mass lesions after head injury and to determine whether there is an isoform-specific effect on the size of the intracranial hematoma. ⋯ Larger hematomas were found in head-injured patients with one or more APOE-epsilon4 alleles than in patients without the allele. This may contribute to the poorer outcomes observed in these patients.
-
Journal of neurosurgery · Jan 2002
Comparative StudyComparative study of traumatic and spontaneous intracerebral hemorrhage.
Spontaneous intracerebral hemorrhage (SICH) and traumatic intracerebral hemorrhage (TICH) are common disorders. The authors planned to study how these two types of hemorrhage behave pathologically and clinically to gain further insight into their causes, pathogeneses, indications for surgical intervention, and prognoses. ⋯ On the basis of these data the authors suggest that TICH and SICH have different features: TICH affects a slightly younger age group and carries a much better prognosis compared with SICH. In addition, indications for surgical intervention are not well defined for either type of hemorrhage. Practice is subjective and inconsistent. The International Surgical Trial in Intracerebral Haemorrhage may resolve the dilemma for SICH. A similar trial in which surgery is compared with conservative management should be considered for cases of TICH.
-
Journal of neurosurgery · Jan 2002
Outcome prediction with serum intercellular adhesion molecule-1 levels after aneurysmal subarachnoid hemorrhage.
Although upregulated adhesion molecule expression has been demonstrated in experimental models of subarachnoid hemorrhage (SAH) and in the cerebrospinal fluid of patients with aneurysmal SAH, the clinical significance of these proinflammatory findings remains unclear. The authors hypothesize that 1) serum levels of soluble intercellular adhesion molecule-l (ICAM-1) are increased in all patients with aneurysmal SAH shortly after the hemorrhagic event, and 2) elevated soluble ICAM-1 values are associated with poor patient outcome, even when controlling for the severity of the initial hemorrhagic insult. ⋯ These data demonstrate a correlation between soluble ICAM-1 levels and functional outcome following aneurysmal SAH that appears to be, at least in part, independent of the initial hemorrhage.
-
Journal of neurosurgery · Jan 2002
Prospective multiple outcomes study of outpatient lumbar microdiscectomy: should 75 to 80% success rates be the norm?
The authors assessed the efficacy and outcomes of lumbar microdiscectomy performed on an outpatient basis by administering six questionnaires before and at five time points after surgery. The results were compared with those reported in literature in which the success rates vary between 70% and 80% and in excess of 90%. The authors use the methodology and data derived from their study to evaluate critically the relevance of these two categories of success rates. ⋯ The findings of this study support the evidence that lumbar microdiscectomy performed on an outpatient basis is a very safe and effective means of treating sciatic pain due to disc herniation. The authors believe that their outcome success rates of 75 to 80% are more realistic than those of 90% or more found in some reports.