摘要:

Brain edema and swelling often complicate surgery for brain tumors. Its pathophysiology is unclear, as is the relationship with brain tissue oxygenation. Our hypothesis was that brain edema around tumor is cytotoxic type caused by impaired local tissue oxygenation due to increased local tissue pressure. Therefore, we monitored brain tissue oxygen pressure (ptiO2) and carbon dioxide pressure (ptiCO2) in 19 patients undergoing craniotomy for removal of a brain tumor and specifically studied the effect of decompression by dura opening and by tumor removal with respect to the presence of brain swelling. Before craniotomy, multiparameter sensors were inserted into the peritumoral brain tissue guided by MRI-based stereotaxy. In eight patients who had severe brain swelling upon opening of the dura mater, ptiO2immediately rose from 7 ± 8 mm Hg to 24 ± 15 mm Hg (P< 0.05), whereas in patients who did not have swelling, ptiO2went from 16 ± 9 to 18 ± 10 mm Hg after opening of the dura. The mean ptiO2of all patients at the start of resection of the tumor was 18 ± 11 mm Hg, and increased to 30 ± 15 mm Hg after resection was completed (P< 0.05). The effect on ptiO2of raising the FiO2to 1.0 was limited in this group of patients, as an increase greater than 50% was found in only six of twelve patients. Notably, in six patients, sensor malfunctions or associated hardware problems occurred, prohibiting useful data acquisition. We conclude that brain tissue oxygenation is reduced in the peritumoral area and improves after local tissue pressure relief, especially in patients with brain swelling. Thus, ischemic processes may contribute to brain edema around tumors. Intraoperative ptiO2monitoring may enhance the safety of neuroanesthesia, but the high incidence of failures with this type of sensor remains a matter of concern.

ISSN:0898-4921    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Although recent surgical microscopes for neurosurgery are equipped with xenon light sources to obtain bright fields of vision, the safety of a xenon beam, which has strong energy intensity in a long ultraviolet light, for cortical neurons has not been evaluated. Cranial windows were made in the parietal bones of gerbils. The skull of each gerbil was covered with warmed saline (0.5 mm in depth) to maintain the brain temperature. Ultraviolet irradiation (365-nm) was performed for 30 minutes at energy levels of 9.6, 4.4, 1.3, and 0.3 mwatts/cm2, and neuronal damage was observed in 90 ± 4%, 42 ± 23%, 9 ± 6%, and 0 ± 0% of pyramidal cells in the parietal cortex 24 hours later. With the use of a logistic regression curve, the energy level causing 50% of neuronal damage was estimated to be 5.4 mwatts/cm2. By increasing the thickness of the saline layer over the skull surface (1 mm and 2 mm), neuronal damages were significantly attenuated (21 ± 18% and 10 ± 8%, respectively, 4.4 mwatts/cm2). Because the highest energy levels of 365-nm ultraviolet rays emitted from surgical microscopes measured in the present study (0.379 mwatts/cm2) were much closer to the dose causing 0% damage than to the dose causing 9% damage, the risk of neuronal injury occurring during microsurgery could be negligible. However, care should be taken in patients who take medicine classified as photosensitizing agents, such as diphenylhydantoin, which are thought to concentrate ultraviolet energy. The use of saline over the cortical surface may be beneficial for reducing the detrimental effects of 365-nm ultraviolet light.

ISSN:0898-4921    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

In this study we assess the clotting onset time (COT) in samples from a population of traumatic brain injury patients. The patients were randomized to standard treatment plus high dose antithrombin (AT group) or standard treatment alone (nonAT group), during the first 16 hours after hospital admission. Our aim was to study the two patient groups during the first 5 days after injury, to assess COT as a coagulation monitoring method compared to routine parameters (thrombin-antithrombin complex (TAT), D-dimer, and soluble fibrin), and to correlate COT to clinical parameters and outcome. Clotting onset time measurements are carried out using free oscillating rheometry, where the endpoint of coagulation onset is determined by a deviation from initial viscoelastic properties of an oscillating sample. Both patient groups initially showed hypercoagulation. In the AT group, a significant increase of COT (i.e., decrease in hypercoagulation), was already seen 16 hours after hospital admission, but not until day 3 in the non AT group. Routine coagulation tests were not able to discriminate AT patients from nonAT patients. Clotting onset time correlated significantly to soluble fibrin, D-dimer, TAT, and leukocyte count. Additionally, COT levels at hospital admission correlated to outcomes measured with the Glasgow Outcome Scale (GOS) after 3 months. These results indicate that COT may be a clinically relevant variable with prognostic value, able to monitor the degree of hypercoagulation over time.

ISSN:0898-4921    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Conflicting reports on the usefulness of intraoperative monitoring of visual function by means of visual evoked potentials (VEPs) initiated this study. In 32 patients without visual problems, VEPs were recorded to evaluate the reliability for intraoperative monitoring with total intravenous anesthesia. All patients underwent noncranial surgery. Using a standard technique, VEPs were recorded preoperatively in the awake patients and after induction of anesthesia during surgery. A total of 1436 intraoperative traces were recorded and analyzed. A minor prolongation of the P100 latency of 8% and a more pronounced attenuation of the P100-N145 amplitude of 60% were observed in the anesthetized patients. In most of the anesthetized patients, a stable recording of VEPs was not obtainable. In 4 patients (12.5%), clearly identifiable VEP peaks were detected in more than 90% of the traces recorded intraoperatively. In 88% of the patients, reproducible VEPs were obtained in less than 75% of the intraoperative traces only. We concluded that with standard recording techniques and total intravenous anesthesia, intraoperative VEP monitoring in surgically anesthetized patients is not reliable.

ISSN:0898-4921    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Several case reports and small clinical series have reported benefits of decompressive hemicraniectomy in patients with intractable cerebral edema and early clinical herniation. Specific indications and timing for this intervention remain unclear. We present our experience with this procedure in a subset of 18 patients with massive cerebral edema refractory to medical management, treated with decompressive craniectomy over a 3-year period (1997 to 2000). Computerized tomography (CT) scans were independently analyzed by a neuroradiologist blinded to clinical outcome. Eleven male and seven female patients, ages 20 to 69 years (mean ± SEM, 46 ± 14 years), underwent hemicraniectomy for the following diagnoses: 12 hemispheric infarcts, 3 traumatic intracerebral hemorrhages/contusions, 2 nontraumatic intraparenchymal hemorrhages (ICH), and 1 subdural empyema. This population included four patients with aneurysmal subarachnoid hemorrhage (SAH). Patients were followed for a mean of 10 months. Clinical factors including age, side of lesion, preoperative herniation signs, and early surgery (<12 or <24 hours) were not significantly associated with mortality or Glasgow outcome score (GOS). Preoperative CT evidence of transtentorial herniation (present in 5/17 patients) was associated with mortality (P= 0.04), while preoperative uncal herniation (8/17 patients) was associated with poor outcome (GOS > 1) (P= 0.01). Favorable outcome (GOS > 3) occurred in six patients, three with spontaneous or traumatic focal hematomas. Of four patients with SAH, one died while the others were severely disabled (GOS 3). Seven of nine patients with malignant MCA infarctions unrelated to SAH had poor outcomes. The overall mortality was 4/18 (22%). Patients with refractory cerebral swelling secondary to focal hematomas may have better outcomes following decompressive craniectomy. Patients with preexisting SAH seem to have poor outcomes, possibly related to other neurologic comorbidities. Hemicraniectomy requires definition of proper timing. Preoperative CT findings, especially transtentorial and uncal herniation may be useful in defining when decompressive surgery should not be performed.

ISSN:0898-4921    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Brain tissue oxygen monitoring (PtiO2(Neurotrend, Codman, Germany) was employed in addition to standard intracranial pressure (ICP) and cerebral perfusion pressure (CPP) monitoring in seven patients with severe neuronal damage of heterogeneous etiology. The correlation between PtiO2changes and CPP fluctuations during periods of 30 minutes were analyzed, when CPP was above 70 mmHg and lower than 100 mmHg. A new ratio, the CPP-oxygen-reactivity (COR) index was calculated as COR=&Dgr;ptiO2%/&Dgr;CPP%. The patient COR values were compared to those found in the brain of six noninjured anesthetized piglets. The analysis was performed to determine the significance of synchronous fluctuations of CPP and PtiO2, when CPP is above the lower threshold of autoregulation. The correlation between CPP variations and ptiO2variations was found to be strong (Rmean= 0.74 ± 0.17) in the patients and was weak in the uninjured animals (Rmean=0.38 ± 0.43). The CORmeanwas 2.05 ± 0.57 in patients and 0.78 ± 0.6 in the animals. In the injured brain of our patients, we observed an unexpectedly close correlation between PtiO2and CPP variations when CPP levels were within a therapeutically targeted range (70 to 100 mmHg). In a porcine model, we could not find this relationship in the noninjured brain. We speculate that an increased COR might be indicative for an impaired local pressure autoregulation. The preliminary data suggest that COR values above “1” might be pathologic. However, the reported sample sizes are too small to provide sufficient statistical power to justify inferential statistical analyses. As such, results are presented with descriptive statistics only, and should be regarded as a hypothesis.

ISSN:0898-4921    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Carotid dissection is a major complication of blunt head and neck trauma. The authors describe a case report of sudden bleeding of a distal branch of the external left carotid artery caused by a fracture of the mandible. This event occurred a week after the trauma. After a first phase consisting in cardiopulmonary resuscitation and blood loss replacement, the placement of a Guglielmi detachable coil (GDC) was considered the best and safest way to stop the bleeding. Guglielmi detachable coil represents a good technique for emergency treatment of bleeding from distal carotid vessels. Given its high cost, the diagnostic study of vessels near mandible fractures should not be considered as routine in cases of head and neck trauma, but should be considered in the presence of local hemorrhage or suspicious neurologic signs.

ISSN:0898-4921    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Subdural hematoma is a rare complication of spinal anesthesia. This patient underwent bilateral inguinal herniorrhaphy under spinal anesthesia 40 days prior to admission. Two days after spinal anesthesia, the patient described a typical postdural puncture headache. Oral analgesics, fluid therapy, and lying flat were recommended. Because of prolonged headache, computed tomography scan was performed and demonstrated chronic subdural hematoma in the left fronto-temporo-parietal region. After surgical drainage, the patient fully recovered. Prolonged headache should be regarded as a warning sign of subdural hematoma.

ISSN:0898-4921    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

We report the case of a child with Moyamoya disease during a cerebral angiography procedure in which the effects of propofol on the cerebral perfusion were seen to be different compared with isoflurane. We suggest propofol was associated with a better preservation of cerebral circulation compared to isoflurane in this case of Moyamoya, as it maintained blood supply to the watershed areas.

ISSN:0898-4921    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Recently, a new method for placing nasogastric tubes (NGT) in dysphagic patients was proposed, which uses the swallowing reflex and was therefore called `reflex placement.` The authors describe the use of this method in a patient with a large left sided striatocapsular hemorrhage, in whom decompressive craniotomy had been performed previously. Whereas the conventional approach of placing NGT led to a massive increase of intracranial pressure (ICP) and to a decline in cerebral perfusion pressure (CPP), the new method allowed a swift placement with only minor changes of ICP and CPP. The strict avoidance of intermittent peaks of ICP constitutes a basic principle of care in patients with space occupying brain lesions. We therefore suggest that, despite the admittedly larger effort, the reflex placement of NGTs should be used in such circumstances.

ISSN:0898-4921    

出版商:OVID    

年代:2003

数据来源: OVID