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- Shahsavari, Sima, 1976, et al.
(författare)
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A comparison between the transfer function of ABP to ICP and compensatory reserve index in TBI
- 2008
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Ingår i: Acta Neurochirurgica, Supplement. - Vienna : Springer Vienna. - 0065-1419. - 9783211855775 ; 102:102, s. 9-13
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The transfer functions which map the arterial blood pressure to the intracranial pressure and the compensatory reserve index have been investigated by various groups to evaluate the brain compliance of patients with traumatic brain injury. The focus of this study has been to assess the capability of both the above mentioned methods to monitor the intracranial compliance in patients suffering from brain swelling. MATERIALS AND METHODS: Clinical data was collected from sixteen traumatic brain injury patients and split into 4 min segments. For each segment, both the magnitude of the empirical transfer function at the fundamental cardiac frequency and the compensatory reserve index were extracted. FINDINGS: The mean values of the compensatory reserve index and the magnitude of the transfer function which scored higher than 0.7 and 0.1 respectively were recorded for all patients suffering from brain swelling. By comparing the histogram of the magnitude of the transfer function at the fundamental cardiac frequency with the histogram of the compensatory reserve index for all patients, a positive correlation between the mean values and a negative correlation among their variances were observed. The linear correlation between the mean values was estimated at r = 0.82 (p
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| 2. |
- Ansar, Saema, et al.
(författare)
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Elevated intracranial pressure or subarachnoid blood responsible for reduction in cerebral blood flow after SAH
- 2008
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Ingår i: Cerebral Vasospasm: New Strategies in Research and Treatment. - Vienna : Springer Vienna. - 0065-1419. - 9783211757178 ; 104, s. 231-233
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Konferensbidrag (refereegranskat)abstract
- Background. The pathogenesis of cerebral ischemia after subarachnoid hemorrhage (SAH) still remains elusive. The purpose of the present study was to examine whether it is the change in intracranial pressure (ICP) or the extravasated blood that is responsible for cerebral ischemia and cerebral vasoconstriction observed following SAH. Method. Three groups of animals were studied; (1) cisternal injection of 250 mu l blood (SAH), (2) injection of 250 mu l NaCl (saline) or (3) same procedure in every detail but no fluid injection (sham). Two days after the treatment, an autoradiographic technique was used to investigate the cerebral blood flow (CBF). Findings. Both SAH (blood+ ICP) and saline injection (ICP only) resulted in significantly reduced regional and global CBF after as compared to sham/control. Conclusions. This study revealed that both the elevation of ICP and A Subarachnoid blood per se contribute approximately equally to the SAH induced effects.
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| 3. |
- Ansar, Saema, et al.
(författare)
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Subarachnoid hemorrhage induces upregulation of vascular receptors and reduction in rCBF via an ERKI/2 mechanism
- 2008
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Ingår i: Cerebral Vasospasm: New Strategies in Research and Treatment. - Vienna : Springer Vienna. - 0065-1419. - 9783211757178 ; 104, s. 65-67
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Konferensbidrag (refereegranskat)abstract
- Previous studies have shown that endothelin type B (ETB) and 5-hydroxytryptamine type IB (5-HTIB) receptors are upregulated following subarachnoid hemorrhage (SAH). The purpose of the present study was to test whether extracellular signal-regulated kinase (ERKI/2) inhibition could alter the degree of SAH induced receptor upregulation in addition to prevent the cerebral blood flow (CBF) reduction. The ERKI/2 inhibitor SB386023-b was injected intra cisternally in conjunction with and after the induced SAH in rats. Two days after SAH cerebral arteries were harvested and the contractile response to endothelin-1 (ET-I) and 5-carboxamidotryptamine (5-CT) were investigated with a myograph. The contractile responses to ET-I and 5-CT were increased after SAH compared to sham. Administration of SB-386023-b prevented the upregulated contraction elicited by application of ET-I and 5-CT in cerebral arteries. Regional CBF evaluated by an autoradiographic technique, revealed a reduced CBF by 50% after SAH this was prevented by treatment with SB-386023-b. The results indicate that an ERKI/2 mechanism is involved in cerebral vasospasm and ischemia associated with SAH.
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| 7. |
- Bjorkman, A, et al.
(författare)
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Cortical reintegration of a replanted hand and an osseointegrated thumb prosthesis
- 2007
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Ingår i: Acta Neurochirurgica. Supplementum. - 0065-1419. ; 100, s. 109-112
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Following a peripheral nerve repair the injured nerve has to re-innervate its original cortical area, a process, which is poorly understood. Errors in this cortical re-innervation have been suggested as one key reason for the generally poor clinical outcome following nerve injuries in the hand. METHOD: Functional magnetic resonance imaging (fMRI) was used to assess cortical reintegration following amputation and reattachment of bodyparts in two different situations: a patient with a hand amputation followed by immediate surgical replantation and a patient with an osseointegrated thumb prosthesis. FINDINGS: The primary motor cortex rapidly returns to a normal activation pattern after amputation followed by replantation or application of an osseointegrated prosthesis. The primary somatosenory cortex changes from an initial ipsilateral to a bilateral activation pattern. Sensory stimulation of an osseointegrated prosthesis also shows a bilateral activation pattern in the primary somatosenory cortex. CONCLUSIONS: The primary motor cortex shows a more normal activation pattern possibly because most muscles controlling the hand are proximal to the injury and can be activated after an amputation. The primary somatosensory cortex reorganises more and the activation pattern is more bilateral compared to a healthy hand. This bilateral activation pattern could represent a compensatory mechanism for the inferior tactile function in the replanted hand and the osseointegrated prosthesis.
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