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S Schwab

Publications and source records attributed to S Schwab.

At least 37 records · Page 2Linked to original sources
PubMed2002

[Current concepts of intensive care of space-occupying middle cerebral artery infarct].

The aim of this paper is to review new developments in the intensive care of patients with space-occupying middle cerebral artery infarctions. Elevated blood pressure should not be treated; however, there is no scientific basis to induce arterial hypertension in these patients. It is not recommended generally to nurse the patients in a position with the head elevated. If therapy is targeted for an optimum cerebral perfusion pressure, the patients should be nursed in a flat position. Decompressive surgery is associated with a marked reduction in an otherwise high mortality. The functional outcome after surgery is similar to the outcome of the survivors after conventional treatment alone. Treatment options for an acutely raised intracranial pressure are mannitol or hypertonic saline solutions, although the long-term effects have not been ascertained yet. There is not enough evidence supporting a prophylactic standard therapy with hypertonic solutions. Patients who require artificial ventilation can be safely ventilated using PEEP or an inverse inspiration/expiration ratio, if the blood pressure is monitored and a possible drop of the arterial blood pressure is treated. Corticoids and hemodilution are obsolete therapies in these patients.

Blood Pressure↗
PubMed2002

Noninvasive monitoring of hypertensive breakthrough of cerebral autoregulation in a patient with acute ischemic stroke.

BACKGROUND AND PURPOSE: We describe the first documentation of hypertensive breakthrough of cerebral autoregulation in a patient with acute stroke with transcranial Doppler sonography. CASE DESCRIPTION: A 55-year-old patient with acute left hemispheric stroke was treated with moderate hypothermia. He died of transtentorial herniation 4 days after admission. Static cerebral autoregulation (sCA) of the unaffected hemisphere was evaluated 6 times during this period and always found to be intact. A bolus application of epinephrine resulted in a hypertensive episode (mean arterial pressure (MAP) 135 mm Hg); hypertensive breakthrough of cerebral autoregulation was evident when MAP exceeded approximately 110 mm Hg. Interestingly, no such breakthrough was evident during testing of sCA, even when MAP reached 120 mm Hg. CONCLUSIONS: Our observation suggests that (1) the pace of the MAP increase is crucial for the occurrence of a hypertensive breakthrough of the cerebral autoregulation and (2) the disturbance of cerebral autoregulation is potentially longer as previously assumed.

Blood Pressure Monitoring, Ambulatory↗
PubMed2002

Hemicraniectomy and moderate hypothermia in patients with severe ischemic stroke.

BACKGROUND AND PURPOSE: We compared the clinical course of 36 consecutive patients with severe acute ischemic stroke (more than two thirds of the middle cerebral artery territory) treated with hemicraniectomy (CE; n=17) or moderate hypothermia (MH; n=19) in terms of intracranial pressure control, mortality, and specific treatment parameters. METHODS: Over a period of 18 months, patients with severe ischemic stroke were treated with CE when the nondominant hemisphere was affected and with MH when the dominant hemisphere was affected. MH (33 degrees C) was induced with either cold blankets and fans (n=11) or endovascular cooling (n=8). Intracranial pressure was monitored invasively in all cases. RESULTS: Age, sex, cranial CT findings, level of consciousness, and time to treatment were similar between the 2 groups; significant differences were noted in National Institute of Health Stroke Scale (NIHSS) score (20 [range, 18 to 22] and 17 [range, 16 to 18] for MH and CE, respectively) but were not present when NIHSS score was corrected for aphasia (17 [range, 15 to 19] and 17 [range, 16 to 18] for MH and CE, respectively). Mortality was 12% for CE and 47% for MH; 1 patient treated with MH died as a result of treatment complications (sepsis) and 3 of intracranial pressure crises that occurred during rewarming. Duration of mechanical ventilation and of neurological intensive care unit stay did not significantly differ, but duration of catecholamine application and maximal catecholamine dosage were significantly higher in the MH group. CONCLUSIONS: In patients with severe ischemic stroke, CE results in lower mortality and lower complication rates compared with MH. Both treatment modalities, however, are associated with intensive medical treatment and a prolonged stay in the neurological intensive care unit.

Adult↗
PubMed2002

Neuroprotective effect of delayed moderate hypothermia after focal cerebral ischemia: an MRI study.

BACKGROUND AND PURPOSE: In contrast to early hypothermia, the effects of delayed hypothermia in focal cerebral ischemia have not been widely addressed. We examined the influence of delayed hypothermia on secondary ischemic injury, MRI lesion size, and neurological outcome after transient focal cerebral ischemia in a rat model. METHODS: Rats (n=30) were subjected to transient middle cerebral artery occlusion (MCAO, 120 minutes) by use of the intraluminal filament model. Animals of the treatment group (n=12) were exposed to whole-body hypothermia of 33 degrees C for 5 hours starting 3 hours after MCAO, whereas the control group (n=18) was kept at 37 degrees C throughout the whole experiment. The normothermia- and hypothermia-treated animals were investigated daily by using the Menzies neurological score. Serial MRI was performed 1, 3, and 6 hours after MCAO and on days 1, 2, 3, and 5. After the final MRI scan, the rats were euthanized, and brain slices were stained by 2,3,5-triphenyltetrazolium chloride. RESULTS: Delayed hypothermia resulted in a significant increase of survival rate and a significant improvement of the Menzies score. Moreover, a significant decrease in the extent of hyperintense volumes in T2-weighted scans and a reduction of cerebral edema as calculated from T2-weighted scans throughout the examination period were obvious. The extent of cerebral infarct volume and cerebral brain edema examined by MRI was consistent with 2,3,5-triphenyltetrazolium chloride staining. CONCLUSIONS: Our results suggest that even delayed postischemic hypothermia can reduce the extent of infarct volume and brain edema after transient focal cerebral ischemia.

Animals↗
PubMed2002

Cerebral autoregulation under moderate hypothermia in patients with acute stroke.

BACKGROUND AND PURPOSE: We undertook this study to examine the integrity of cerebral autoregulation in patients with acute ischemic stroke treated with moderate hypothermia (33 degrees C). METHODS: Fourteen patients, aged 58+/-11 years, with an acute anterior circulation infarction and National Institutes of Health Stroke Scale score >15 were evaluated. Patients received catecholamines (norepinephrine) via continuous intravenous infusion and were mechanically ventilated. Alpha-stat was used for pH maintenance. Arterial pressure (AP) and intracranial pressure (ICP) were invasively monitored. Flow velocity in the middle cerebral artery (MCA) supplying the unaffected hemisphere was continuously monitored. Instantaneous maximum flow velocity (V(max) MCA), ICP, and AP were simultaneously recorded in real time. Mean values of V(max) MCA (V(mean) MCA) and AP (MAP) were calculated over 1 minute. Static cerebral autoregulation (sCA) was calculated as sCA=(%DeltaCVR/%DeltaMAP)x100% (where %DeltaCVR is an estimate of percent change in cerebrovascular resistance). An sCA value of 0% indicates absent autoregulation, and a value of 100% indicates perfect autoregulation. Autoregulation is considered impaired when sCA values are <40%. MAP changes were produced by increasing the rate of the norepinephrine infusion. Six patients were examined under both normothermic and hypothermic conditions, while 8 were examined only under hypothermia. RESULTS: The induced MAP increase was 22+/-7 mm Hg (minimum 13, maximum 40 mm Hg). Mean sCA was 64+/-16% (minimum 40%, maximum 100%). No effect of moderate hypothermia on sCA or V(mean) MCA was evident in any of the 6 serially examined patients. Normocapnia was observed in all cases. CONCLUSIONS: sCA appears intact under moderate hypothermia with the use of alpha-stat for pH maintenance.

Acute Disease↗
PubMed2001

Effect and feasibility of controlled rewarming after moderate hypothermia in stroke patients with malignant infarction of the middle cerebral artery.

BACKGROUND AND PURPOSE: Moderate hypothermia has been found to reduce intracranial pressure (ICP) significantly in patients who have severe middle cerebral artery infarction. However, during passive rewarming, ICP continuously rises and some patients suffer transtentorial herniation. METHODS: We investigated the question of whether slower rewarming leads to slower increase in ICP and slower decrease in cerebral perfusion pressure (CPP). Furthermore, we studied feasibility of slow, controlled rewarming. ICP, CPP, and core body temperature were monitored continuously. Achievement of rewarming protocol was assessed by hit rate of temperature target intervals. Side effects of hypothermia were assessed. RESULTS: Rates of change of both ICP and CPP were correlated significantly with increase in temperature (ICP r=0.62, P=0.002; CPP r=-0.50, P=0.017). In feasibility analysis of 13 controlled rewarmed patients, hit rate of temperature target intervals was 63% (median; range 48% to 81%); hit rate within the target interval or below was 79% (median; range 62% to 94%). CONCLUSIONS: Slow, controlled rewarming is feasible and may be used for ICP and CPP control after moderate hypothermia for space-occupying infarction.

Body Temperature↗
PubMed2001

Masking of vertebral artery dissection by severe trauma to the cervical spine.

STUDY DESIGN: A prospective case study was performed. OBJECTIVES: To illustrate the association of cervical trauma with vertebral artery dissection, and to propose a diagnostic and therapeutic algorithm for suspected traumatic vertebral artery dissection. SUMMARY OF BACKGROUND DATA: Vertebral artery dissection is a recognized but underdiagnosed complication of trauma to the cervical spine. Symptoms of spinal cord injury, however, may obscure those of vertebral artery dissection, presumably causing gross underdiagnosis of this complication. METHODS: All patients with vertebral artery dissection admitted to the authors' facility between 1992 and 1997 were screened for cervical trauma. RESULTS: This article presents four patients with severe trauma to the cervical spine, defined as luxation, subluxation, or fracture, in whom symptoms of vertebral artery dissection developed after a delay ranging from several hours to weeks. The traumatic vertebral artery dissection typically was located at the site of vertebral injury or cranial to it. One patient with fracture of the odontoid process survived symptom free without ischemic brain infarctions. Another patient survived with traumatic quadriplegia in addition to large cerebellar and posterior cerebral artery infarctions. Two patients died as a result of fulminant vertebrobasilar infarctions, both with only moderate impairment from the primary spinal cord injury. CONCLUSIONS: Early signs of vertebral artery dissection include head and neck pain, often localized to the site of intimal disruption, which may be disguised by the signs of the spinal injury. Early Doppler ultrasound and duplex sonography as a noninvasive screening method should be performed for patients with severe trauma to the cervical spine. In cases of vertebral artery dissection, immediate anticoagulation should be initiated. Traumatologists should be aware of this complication in evaluating patients with severe trauma of the cervical spine, and also for a variety of forensic reasons.

Adult↗
PubMed2001

Neurometabolic changes during treatment with moderate hypothermia in a patient suffering from severe middle cerebral artery infarction.

Microdialysis is a means of measuring neurochemical changes in the extracellular space and has been applied in acute brain trauma, subarachnoid hemorrhage and stroke patients. In this study, we monitored neurochemical changes in the extracellular space using microdialysis in a patient with left-sided hemispheric infarction treated with moderate hypothermia (33 degrees C). Microdialysis probes were obtained from the infarcted and noninfarcted hemisphere during hypothermia and rewarming. Concentrations of extracellular substances in the infarcted hemisphere (glutamate, glycerine, lactate/pyruvate) decreased with hypothermia and remained stable (glutamate) or increased (glycerine, lactate/pyruvate) during rewarming. Concentrations of these substances in the noninfarcted hemisphere remained at normal levels. Microdialysis monitoring of therapeutic hypothermia in severe hemispheric infarction might be a useful additional monitoring tool to assess the status of the brain and to predict further deterioration.

Adult↗
PubMed2001

Microbiological quality of topical drug formulations: efficacy of antimicrobial preservation against Paecilomyces lilacinus.

BACKGROUND: Microbiological quality of topical products comprises both, the microbiological purity of the unopened product and the efficacy of the antimicrobial preservation system. OBJECTIVE: Subsequent to an outbreak of invasive Paecilomyces lilacinus mycosis among patients of an isolation ward, probably caused by a contaminated skin care product, the microbiological quality of different skin care products from the market was investigated. METHODS: The different products were investigated for their efficacy of antimicrobial preservation in general and especially against P. lilacinus according to a pharmacopoeial routine method slightly adopted for the purpose of this investigation. RESULTS: The products did partially not comply with the British Pharmacopoeia 1993 test for efficacy of antimicrobial preservation. The antimicrobial preservation systems were less effective against P. lilacinus than against the pharmacopoeial reference germs. The antimicrobial preservation efficacy decreased towards the end of the shelf-life of the product. A decreased P. lilacinus inoculum dose was related to an increased growth of the micro-organisms. CONCLUSION: Topical products are, unless not labelled otherwise, non-sterile preparations and their preservation systems are only tested against pharmacopoeial key micro-organisms. The microbiological behaviour following contamination with other germs remains unknown.

Administration, Topical↗
PubMed2001

Delayed neuroprotective effect of insulin-like growth factor-i after experimental transient focal cerebral ischemia monitored with mri.

BACKGROUND AND PURPOSE: Insulin-like growth factor (IGF) treatment has been shown to have trophic and neuroprotective effects in vitro and in vivo in different lesion models. IGF-I has potent neuroprotective effects after hypoxic-ischemic injury and global ischemia. The role of IGF-I in focal cerebral ischemia is only partially understood. Therefore, in the present study, we evaluated, by applying MRI monitoring, whether a clinically relevant systemic administration of IGF-I can achieve a long-lasting neuroprotective effect. METHODS: Male Wistar rats underwent transient occlusion of the right middle cerebral artery for 1 hour by using the suture occlusion model. Animals then were intraventricularly treated with 33.33 microg IGF-I/d for 3 days (group A, the IGF-I group [n=13]; group B, the placebo group [n=14]) or subcutaneously treated with 200 microg IGF-I/d for 7 days (group D, the IGF-I group [n=10]; group E, the placebo group [n=10]). Groups C and F served as sham-operated controls (n=5 and n=3, respectively). Treatment was begun 30 minutes after occlusion of the middle cerebral artery. Subcutaneously treated animals underwent MRI studies (diffusion-weighted imaging, perfusion imaging, and T2-weighted imaging) beginning 60 minutes after vessel occlusion at 6 hours and at days 1, 2, 5, and 7 after ischemia. The animals were weighed and neurologically assessed daily (rating scale ranged from 0, indicating no deficit, to 5, indicating death). On the third day (intraventricular trial) and on the seventh day (subcutaneous trial), animals were euthanized, and brain sections were stained with triphenyltetrazolium chloride. RESULTS: The mean infarct volume was 52.9+/-25.2 mm(3) in intraventricularly treated animals versus 146.4+/-62.2 mm(3) in control animals (P<0.01) and 42.2+/-17.9 mm(3) in subcutaneously IGF-I-treated animals versus 73.1+/-38.1 mm(3) in control animals (P<0.05). Apparent diffusion coefficient-derived lesion volume at 60 minutes after occlusion was 40.4+/-23.7 mm(3) versus 38.3+/-19.3 mm(3) (P=NS), increased to 168.3+/-49.55 mm(3) versus 105.5+/-33.8 mm(3) (P<0.05) at 24 hours, and then decreased to 55.8+/-30.3 mm(3) versus 23.3+/-20.2 mm(3) (P<0.05) for control and IGF-I-treated animals, respectively. The T2-weighted-derived ischemic lesion volume at 24 hours after occlusion was 236+/-49.2 mm(3) versus 115.9+/-56.8 mm(3) (P<0.05) and decreased to 115.9+/-26.2 mm(3) versus 75.7+/-35.8 mm(3) (P<0.05) at day 7 for control and IGF-I-treated animals, respectively. The relative regional cerebral blood volume was reduced to 50% before reperfusion in all regions of interest except for region of interest 1 (vessel territory of anterior cerebral artery), recovered during reperfusion, but was not different between the control and the growth factor-treated group at any imaging time point. There was no significant difference in weight loss. There was less neurological deficit after ischemia in intraventricularly and subcutaneously IGF-I-treated animals compared with control animals (P<0.05). CONCLUSIONS: Continuous treatment with intraventricularly and subcutaneously administered IGF-I achieved a long-lasting neuroprotective effect as early as 24 hours after ischemia as measured by MRI. Therefore, IGF-I may represent a new approach to the treatment of focal cerebral ischemia.

Animals↗
PubMed2001

Feasibility and safety of moderate hypothermia after massive hemispheric infarction.

BACKGROUND AND PURPOSE: Moderate hypothermia decreases ischemic damage in experimental stroke models. This multicenter study was performed to evaluate (1) the safety and feasibility of moderate hypothermia and (2) its potential to reduce intracranial hypertension in acute stroke patients. METHODS: Fifty prospective patients with cerebral infarction involving at least the complete middle cerebral artery territory treated with moderate hypothermia were evaluated. Hypothermia was induced with the use of cooling blankets as well as alcohol and ice bags within 22+/-9 hours after stroke onset and maintained for 24 to 72 hours; subsequently, patients passively rewarmed over a mean duration of 17 hours. Outcome was assessed at 4 weeks and at 3 months. RESULTS: Time required for cooling to <33 degrees C varied from 3.5 to 11 hours. The most frequent complications of hypothermic therapy were thrombocytopenia (70%), bradycardia (62%), and pneumonia (48%). Four patients (8%) died during hypothermia as a result of severe coagulopathy, cardiac failure, or uncontrollable intracranial hypertension. An additional 15 patients (30%) died during or after rewarming because of rebound increase in intracranial pressure (ICP) and fatal herniation. A shorter (<16 hours) rewarming period was associated with a more pronounced rise of ICP. Elevated ICP values were significantly reduced under hypothermia. Neurological outcome according to the National Institutes of Health Stroke Scale score 4 weeks after stroke was 29, and Rankin Scale score 3 months after stroke was 2.9. CONCLUSIONS: Moderate hypothermia is feasible in patients with acute stroke, although it is associated with several side effects. Most deaths occur during rewarming as a result of excessive ICP rise. Our preliminary observation that a longer duration of the rewarming period limits the ICP increase remains to be confirmed in future studies.

Acute Disease↗
PubMed2001

Influence of positive end-expiratory pressure on intracranial pressure and cerebral perfusion pressure in patients with acute stroke.

BACKGROUND AND PURPOSE: We undertook this study to evaluate the influence of positive end-expiratory pressure (PEEP) on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) in patients with acute stroke. METHODS: A total of 20 ventilated patients of a neurological intensive care unit were examined under a protocol entailing variation of PEEP to 4, 8, 12, and 4 mm Hg; mean arterial blood pressure (MAP), ICP, heart rate, and mean velocity of the middle cerebral arteries (V(m) MCA) were recorded. RESULTS: CPP significantly changed depending on the various PEEP levels. No significant differences in remaining parameters were evident. Three distinct reaction patterns of the parameters monitored were observed: (1) All parameters remained stable through the various PEEP levels (15 patients, 40 examinations). (2) Increase in PEEP resulted in a significant decrease of MAP, while V(m) MCA remained unchanged, indicating an intact cerebral autoregulation. A slight (statistically insignificant) increase in ICP, which was significantly related to the MAP changes, was evident (7 patients, 16 examinations). (3) Increase in PEEP resulted in a decrease of MAP and V(m) MCA; ICP remained unchanged or demonstrated a slight decline (3 patients, 6 examinations). CONCLUSIONS: PEEP increase up to 12 mm Hg does not significantly influence ICP. The observed marked changes in CPP are mediated through the MAP. Thus, PEEP application should be safe, provided that MAP is maintained.

Adult↗
PubMed2001

Endovascular cooling for moderate hypothermia in patients with acute stroke: first results of a novel approach.

BACKGROUND AND PURPOSE: We undertook this study to evaluate the feasibility of inducing and maintaining moderate hypothermia with the use of endovascular rather than surface cooling. METHODS: Six patients with severe acute ischemic stroke were treated with moderate hypothermia. This was induced and maintained by circulating temperature-adjusted normal saline in a closed-loop system entailing 3 balloons located near the tip of a central line, which dwelled in the inferior vena cava. RESULTS: The mean+/-SD initial temperature of the patients was 37+/-1 degrees C (range, 35.5 degrees C to 38.4 degrees C). The pace of cooling was 1.4+/-0.6 degrees C/h, and target temperature was reached after 3+/-1 hours (range, 2 to 4.5 hours). During hypothermia, the maximal temperature observed was 33.4 degrees C, and the minimal temperature was 32.2 degrees C. Temperature deviations >0.2 degrees C or >0.3 degrees C were observed during 21% or 10% of the hours under hypothermia, respectively. Singultus was the only device-related complication encountered. Pulmonary infection, arterial hypotension, bradycardia, arrhythmia, and thrombocytopenia were the most common side effects. CONCLUSIONS: Induction and maintenance of hypothermia with an intravenous cooling device are feasible. The safety of this approach remains to be evaluated.

Acute Disease↗
PubMed2001

Combination of decompressive craniectomy and mild hypothermia ameliorates infarction volume after permanent focal ischemia in rats.

BACKGROUND AND PURPOSE: Both hypothermia and decompressive craniectomy (DC) have been shown to reduce ischemic injury in experimental middle cerebral artery (MCA) infarction. This study was designed to evaluate the effect of combined DC and hypothermia on infarction size and neurological outcome in a rat model of MCA occlusion (MCAO). METHODS: MCAO was performed in 72 Wistar rats assigned to groups A through F. In group A, mild hypothermia (32 degrees C) was induced 1 hour after MCAO for 5 hours; normothermia was maintained in group B. After 6 hours of survival, infarction size was calculated for animals of groups A and B. In group C, DC alone was performed 4 hours after MCAO; hypothermia without DC was performed 1 hour after MCAO and maintained for 5 hours in group D. Combined DC and hypothermia were performed in group E. No therapy was performed in group F (control). Infarction size and neurological performance after 24 hours were used as study end points (groups C through F). RESULTS: Permanent postischemic hypothermia significantly reduced infarction size 6 hours after MCAO compared with controls (group A, 6.6+/-2.4%; group B, 20.2+/-2.6%; P<0.01). Twenty-four hours after MCAO, infarction size was not significantly reduced by hypothermia alone (group D, 21.9+/-3.6%). Compared with controls (group F, 23.3+/-3.3%), infarction size was significantly reduced and neurological performance was significantly improved in animals treated by DC (group C, 11.8+/-3.4; P<0.001). Combined hypothermia and DC resulted in additional reduction of infarction size (group E, 9.1+/-2.4%) and improved neurological score (P<0.01). CONCLUSIONS: Early DC significantly reduces infarction size and improves neurological outcome in MCA infarction in rats. Temporary mild hypothermia delays infarct evolution but does not significantly reduce definite infarction size or improve neurological outcome. Combined hypothermia and DC yield significant additional benefit.

Animals↗
PubMed2001

Suboptimum hemicraniectomy as a cause of additional cerebral lesions in patients with malignant infarction of the middle cerebral artery.

OBJECT: The goal of this study was to determine the frequency of hemicraniectomy-associated lesions and their potential effect on the risk of mortality in patients suffering from malignant infarction of the middle cerebral artery MCA). METHODS: The authors evaluated serial computerized tomography scans obtained in 60 patients with complete infarction of the right MCA who were treated using hemicraniectomy. The maximum diameter of the hemicraniectomy was determined and the hemicraniectomy-associated lesions were classified as ischemic lesions or hemorrhages. The category of hemorrhages was composed of parenchymal, subdural, or epidural/subgaleal hematomas. Parenchymal hemorrhages and infarcts associated with hemicraniectomy occurred with frequency rates of 41.6% and 28.4%, respectively. The occurrence of hemicraniectomy-associated bleeding was related to the size of the hemicraniectomy performed; that is, the smaller the hemicraniectomy, the more often lesions occurred (p < 0.05). Hemicraniectomy-associated bleeding was also related to an increased risk of mortality. CONCLUSIONS: Hemicraniectomy is an effective therapy in patients with malignant infarction of the MCA. However, a hemicraniectomy that is too small in diameter may cause the formation of additional lesions and adversely affect the risk of mortality and the quality of survival. In addition, the size and shape of the edges of the bone defect are important factors relating to its efficacy.

Adult↗