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Biomedical subjects

U Linstedt

Publications and source records attributed to U Linstedt.

18 recordsLinked to original sources
PubMed2005

[Duration of migraine disease correlates with amplitude and habituation of event-related potentials].

BACKGROUND: Duration of a migraine disease and hypervigilance are factors which possibly enable the transformation from episodic into chronic migraine. To elucidate this assumption, attentional parameters were measured by recording contingent negative variation (CNV) and correlated with the individual duration of migraine disease. PATIENTS AND METHODS: A total of 28 patients (episodic migraine with or without aura) were compared with 16 healthy controls. CNV analysis included amplitude and habituation calculation. Data were correlated with the individual duration of the migraine disease. The migraine group was divided into two groups based on a median split (short vs long lasting) which were compared by t-tests. RESULTS: Migraine patients produce higher CNV amplitudes than controls. Moreover, migraineurs showed dishabituation while habituation was seen in controls. There was a Pearson correlation coefficient of r = -0.767 between duration of disease and early component of CNV. Patients with long-lasting disease showed lower dishabituation by a higher intercept than patients with short-lasting disease. CONCLUSION: The correlation between duration of disease and attentional parameters and the changing dishabituation can be interpreted as an enhancement in preactivation level in patients with long-lasting migraine. Maybe this change is a prerequisite for transformation into chronic migraine.

Evoked Potentials↗
PubMed2002

[Does intraoperative hyperventilation improve neurological functions of older patients after general anaesthesia?].

UNLABELLED: The purpose of the study was to investigate the effect of intraoperative hyperventilation on postoperative cognitive functions. METHODS: A total of 120 patients (60 older and 60 younger than 65 years old) were allocated randomly to group I "hyperventilation" (p(et)CO(2)=30 mmHg) or group II "normoventilation" (p(et)CO(2)=45 mmHg). Before the operation and on days 1, 3 and 6 after the operation, a battery of neuropsychological tests was performed (concentration endurance test d2, number connection test, digit symbol test). A decline of 20% in at least one test was regarded as postoperative cognitive deficit (POCD). Anaesthesia was maintained with isoflurane in nitrous oxide/oxygen supplemented with fentanyl. RESULTS: In all patients pooled, POCD was present in 26 patients (22%). In patients older than 65 years, POCD was present in 3 cases after hyperventilation and 13 cases after normoventilation ( p<0.01). In younger subjects, 5 cases of POCD were diagnosed in each ventilation group. Furthermore, POCD was more severely pronounced in older patients after normoventilation. CONCLUSION: In older patients, POCD occurred more frequently after intraoperative normoventilation. We assume that a reduced amount of noxious substances reach the brain after hyperventilation, because hyperventilation reduces the cerebral blood flow.

Aged↗
PubMed2002

Serum concentration of S-100 protein in assessment of cognitive dysfunction after general anesthesia in different types of surgery.

BACKGROUND: S-100 protein serum concentration (S-100) serves as a marker of cerebral ischemia in cardiac surgery, head injury and stroke. In these circumstances S-100 corresponds well with the results of neuropsychological tests. The aim of the present study was to investigate the value of S-100 and neuron specific enolase (NSE) in reflecting postoperative cognitive deficit (POCD) after general surgical procedures. METHODS: One hundred and twenty patients undergoing vascular, trauma, urological or abdominal surgery were investigated. Serum values of S-100 and NSE were determined preoperatively and 0.5, 4, 18 and 36 h postoperatively. Neuropsychological tests for detecting POCD were performed preoperatively and on day 1, 3, and 6 after the operation. A decline of more than 10% in neuropsychological test results was regarded as POCD. Furthermore, we retrospectively compared the S-100 in patients with and without POCD in different types of surgery. RESULTS: According to our definition, forty-eight patients had POCD (95% confidence interval: 37.5-58.5). These patients showed higher serum concentrations of S-100 (median 024 ng/ml; range 0.01-3.3 ng/ml) compared with those without POCD (n=69; median 0.14 ng/ml; range 0-1.34 ng/ml) 30 min postoperatively (P=0.01). Neuron specific enolase was unchanged during the course of the study. Differences of S-100 in patients with and without POCD were found in abdominal and vascular surgery but not in urological surgery. CONCLUSION: When all patients are pooled, S-100 appears to be suitable in the assessment of incidence, course and outcome of cognitive deficits. We suspect that in some surgical procedures, such as urological surgery, S-100 appears to be of limited value in detecting POCD. Neuron specific enolase did not reflect neuropsychological dysfunction after noncardiac surgery.

Adolescent↗
PubMed2002

[The abbreviated mental test in a German version for detection of postoperative delirium].

OBJECTIVES: Delirium is the most common acute organic psychosis postoperatively, and occurs more frequently in the elderly than anticipated. The abbreviated mental test (AMT) is a widely used cognitive test in Great Britain. The present study assessed the AMT in a German version for diagnosis of postoperative delirium. METHODS: 40 patients (older than 65 years), scheduled for total knee or hip replacement, were tested repeatedly for delirium according to the ICD-10. These patients were investigated with the AMT simultaneously by a second investigator. RESULTS: Delirium was present in four orthopaedic patients (10 %) and was diagnosed correctly in these patients by the AMT. All but one patient without delirium showed no deterioriation in AMT score. CONCLUSION: As in Great Britain, the AMT in its German version is useful in diagnosing delirium. We recommend the use of the AMT preoperatively in elderly patients at risk for delirium.

Aged↗
PubMed2001

[Treatment of low back pain--significance, principles and danger].

Today, a wide range of efficient analgesic and non-analgesic drugs for the treatment of back pain are available. However, drugs should never be the only mainstay of a back pain treatment program. Non-steroidal antiinflammatory drugs (NSAID) are widely used in acute back pain. NSAIDs prescribed at regular intervals are effective to reduce simple back pain. The different NSAIDs are effective for the reduction of this pain. They have serious adverse effects, particularly at high doses, in the elderly, and on long-term administration. The new cyclooxygenase II-inhibitors have less gastrointestinal complications. But the long-term experiences are limited up to now. Considerable controversy exists about the use of opioid analgesics in chronic noncancer pain. Many physicians are concerned about the effectiveness and adverse effects of opioids. Other clinicians argue that there is a role for opioid therapy in chronic noncancer pain, e. g. especially in chronic low back pain. There is a low incidence of organ toxicity in patients who respond to opioids. The incidence of abuse and addiction is likewise relatively low. The potential for increased function and improved quality of life seems to outweigh the risks. However, there is a lack of randomised controlled trials (RCT) on opioid therapy in a multimodal pain treatment approach. Clinical experience and some studies suggest administration of sustained release opioids because of better comfort for the patient and less risks for addiction. The opioids should be selected due to the specific side effects of the different drugs. For patients with pre-existing constipation transdermal fentanyl should be preferred. Antidepressant medications have been used for the treatment of chronic back pain, though there is only little scientific evidence for their effectiveness. There is no evidence for the use of antidepressants in acute low back pain. Trials of muscle relaxants for patients with acute back pain have used a wide range of agents, e. g. benzodiazepines. They mostly reduce acute back pain, but they have significant adverse effects including drowsiness and psychological and physical dependence even after relatively short treatment. Benzodiazepines are not indicated in the treatment of chronic back pain. Drugs are sometimes necessary for the patients to begin and persevere a multimodal treatment program. Drug therapy should be terminated as soon as other treatment strategies succeed. Unfortunately, no studies exist evaluating the place of analgesics within a multimodal treatment program.

Analgesics, Opioid↗
PubMed2001

Dose-response relationship of propofol on mid-latency auditory evoked potentials (MLAEP) in cardiac surgery.

BACKGROUND: Propofol-sufentanil anaesthesia has become popular during cardiac surgery for its titrability and short recovery time. Avoidance of awareness is a major goal during cardiac surgery. We therefore investigated the dose-response relationship of propofol and cortical responses (mid-latency auditory evoked potentials, MLAEP). METHODS: One hundred patients undergoing cardiac surgery were investigated. Basic anaesthesia was performed with sufentanil (4.5 microg kg(-1) h(-1)) / flunitrazepam (9 microg kg(-1) h(-1)) infusion (control group); the other groups received in addition a loading dose of propofol 2 mg kg(-1) and a maintainance infusion of 1-3.5 mg kg(-1) h(-1). MLAEP were evaluated by using Pa/Nb-amplitudes and Nb-latencies. Haemodynamics were monitored by ECG, arterial blood pressure and cardiac function with pulmonary artery catheterization. RESULTS: In the control group, median amplitude of MLAEP decreased by 50% with a wide range, but were detectable in >90% of patients throughout surgery. Propofol suppressed amplitude Pa/Nb of MLAEP dose dependently. With 3.5 mg kg(-1) h(-1) amplitudes disappeared in >40% of patients throughout cardiac surgery. Median Nb-latencies increased in the control group from 44 to a range from 50 to 60 ms. In groups with propofol >2 mg kg(-1) h(-1), Nb-latencies, detectable in the patients without complete suppression of MLAEP, increased to median 60 ms. Haemodynamic parameters and cardiac function did not differ among the groups. The use of vasopressors was not increased even with the highest propofol dose used. CONCLUSION: The dose-response effect of propofol on auditory evoked potentials reveals that combining a loading dose of 2 mg kg-1 with a consecutive infusion of 3.5 mg kg(-1) h(-1) significantly suppresses MLAEP during cardiac surgery. Thus, auditory information may not be processed and awareness with recall becomes unlikely.

Adolescent↗
PubMed2001

Contingent negative variation and attentional performance in humans.

The relation between a paper-pencil test of sustained attention (d2-letter cancellation test, d2-LCT) and the contingent negative variation (CNV) as a cortical slow potential was calculated in 23 healthy undergraduate students. Both d2-LCT and CNV reflect selective, focussed attention. There was a Pearson correlation coefficient of r = -0.670 between the early component of the CNV and the number of checked letters in d2-LCT, indicating significant differences in early CNV between low and high performance in d2-LCT. The results showed a linear relationship between paper-pencil registered attentional properties and the cortically recorded early component of CNV.

Adult↗
PubMed2000

[Diagnostic value of s-100 protein and neuron-specific enolase as serum markers for cerebral deficiency after general anesthesia. Study in patient with hip or knee replacement].

UNLABELLED: S-100 protein and neuron-specific enolase (NSE) serum concentrations serve as markers of cerebral damage in cardiac surgery, neurology, or after head injury. In these circumstances, S-100 and NSE levels correspond with the results of neuropsychological tests. The present study investigated the diagnostic value in orthopaedic patients after joint replacement. METHODS: Forty patients scheduled for elective hip or knee arthroplasty were investigated. Serum values of NSE and S-100 were determined preoperatively and 30 min and 4, 18, and 36 h postoperatively. Neuropsychological tests (syndrome short test, SKT, delirium assessment according to DSM IV) were performed preoperatively and two, three, and four days following surgery. General anaesthesia was induced with fentanyl and etomidate and maintained with isoflurane in oxygen/air. FINDINGS: The S-100 increased from a median of 0.04 ng/ml (range 0.004-0.19 ng/ml) preoperatively to 1.03 ng/ml (range 0.18-3.65 ng/ml) at 30 minutes postoperatively (P < 0.0001). These levels returned to normal in the course of the following 2 days. NSE values were 8.55 ng/ml (range 4.6-14.9 ng/ml) preoperatively and 7.07 ng/ml (range 4-16.4 ng/ml) postoperatively (P = 0.167). There were no differences in serum concentrations of S-100 and NSE between normal patients and those with postoperative cognitive deficit. Furthermore, no correlation was found between the serum marker and neuropsychological tests. INTERPRETATION: Obviously, increased NSE levels seem to indicate cerebral damage only in more severe cases. S-100 does not seem to be brain-specific in patients undergoing orthopaedic surgery. Therefore, the value of S-100 in the assessment of brain disorders is limited.

Aged↗
PubMed1998

Neuromuscular blocking effects of rocuronium during desflurane, isoflurane, and sevoflurane anaesthesia.

PURPOSE: To determine the magnitude of the potentiation of rocuronium by desflurane, isoflurane and sevoflurane 1.5 MAC anaesthesia. METHODS: In a prospective, randomised, study in 80 patients, the cumulative dose-effect curves for rocuronium were determined during anaesthesia with desflurane, sevoflurane and isoflurane (with N2O 70%, 15 min steady state) or total intravenous anaesthesia (TIVA) using propofol/fentanyl. Neuromuscular block was assessed by acceleromyography (TOF-Guard) after train-of-four (TOF) stimulation of the ulnar nerve (2 Hz every 12 sec, 200 microseconds duration). Rocuronium was administered in increments of 100 micrograms.kg-1 until first twitch (T1) depression > 95%. RESULTS: Rocuronium led to more pronounced T1 depression with desflurane or sevoflurane anaesthesia than with TIVA. The ED50 and ED95 were lower during desflurane (95 +/- 25 and 190 +/- 80 micrograms.kg-1) and sevoflurane (120 +/- 30 and 210 +/- 40 micrograms.kg-1) than with TIVA (150 +/- 40 and 310 +/- 90 micrograms.kg-1) (P < .01), while the difference was not significant for isoflurane (130 +/- 40 and 250 +/- 90 micrograms.kg-1). Following equi-effective dosing (T1 > 95%) the duration to 25% T1 recovery, recovery index (25/75), and TOF0.70 was: 13.2 +/- 1.8, 12.7 +/- 3.4, and 26.9 +/- 5.7 min during anaesthesia with desflurane; 15.5 +/- 5.0, 11.4 +/- 3.8, and 31.0 +/- 6.0 min with sevoflurane; 13.9 +/- 4.7, 10.7 +/- 3.3, and 26.3 +/- 8.9 min with isoflurane; and 13.9 +/- 3.9, 11.3 +/- 5.7, and 27.5 +/- 8.2 min with TIVA anaesthesia (P: NS). CONCLUSION: Interaction of rocuronium and volatile anaesthetics resulted in augmentation of the intensity of neuromuscular block but did not result in significant effects on duration of or recovery from the block.

Adult↗
PubMed1998

Intraoperative monitoring with somatosensory evoked potentials in carotid artery surgery--less reliable in patients with preoperative neurologic deficiency?

BACKGROUND: In a retrospective analysis of intraoperative somatosensory evoked potential (SEP) results during carotid artery surgery we found some cases with postoperative neurologic deficits, surprisingly without significant SEP changes. METHODS: Median nerve SEP were monitored as usual. Indication for selective shunting was a complete loss of amplitude N20/P25 in the first period of the investigation, later on a 50% reduction, or a prolongation of the central conduction time (CCT) of about 1.5 ms after cross-clamping. Anaesthesia was maintained with isoflurane in N2O/O2, fentanyl and atracurium. RESULTS: Over a 3-year period 146 patients were monitored. Indications were: transient ischaemic attacks (TIA) (n=51), stroke (n=23), stroke with residuals (n=39), asymptomatical stenosis (n=29), subclavian steal syndrome (n=4). Twenty-four patients received an intraluminal shunt following SEP alterations. Postoperatively, 5 patients (3.4%) had symptoms of intraoperative brain ischaemia (stroke n=2, TIA n=3), 4 of them showing only minor intraoperative SEP alterations; 1 received a shunt because of CCT prolongation. Four of these 5 patients had cerebral neurologic deficiency preoperatively. CONCLUSION: Since some authors have found a 100% sensitivity of intraoperative SEP, it is remarkable, that 1 patient with postoperative stroke and 3 patients with TIA had no significant SEP changes intraoperatively. We suppose there was an association with preoperative neurological deficits resulting from previous strokes. In such cases, regional critical ischaemia may apparently occur outside the sensory pathway monitored with SEP.

Aged↗
PubMed1997

Effects of selective angiography of the carotid artery with carbon dioxide on electroencephalogram somatosensory evoked potentials and histopathologic findings. A pilot study in pigs.

RATIONALE AND OBJECTIVES: The authors investigate the cerebral effects of selective carotid angiography with carbon dioxide (CO2). METHODS: In 6 pigs, CO2 was injected into the carotid artery with consecutively increasing doses. Cerebral function was monitored with two-channel electroencephalography and somatosensory evoked potentials (SEPs). After the experiment the brains were investigated histopathologically. RESULTS: Initial doses led to reversible decreases in electroencephalograph power by 40% to 80%. Further doses result in partly nonreversible electroencephalographic changes. Somatosensory evoked potential latencies (n = 5) were not changed. Amplitudes were not affected in low dose ranges up to 40 mL CO2. Higher CO2 doses led to different changes. There were no SEP amplitude reductions (n = 1), as well as reversible (n = 2) and nonreversible (n = 2) SEP amplitude reductions. Histopathologically, edema (n = 6), edema necrosis (n = 2), and destroyed cells as a sign of ischemia (n = 2) were found. CONCLUSIONS: Administering CO2 in brain supplying arteries impairs the cerebral function. Consecutive, increasing doses lead to partly nonreversible electroencephalographic and SEP changes and brain tissue damages.

Angiography↗
PubMed1996

Effect of transcutaneous electrical nerve stimulation on onset of axillary plexus block.

We examined the effect of high frequency transcutaneous electrical nerve stimulation on the onset of brachial plexus block. Three groups of patients scheduled for surgery of the hand had a local anaesthetic block performed with 40 ml mepivacaine 1.5% using the axillary approach. After injection of the local anaesthetic transcutaneous electrical nerve stimulation was applied for 15 min either to the median nerve or the ulnar nerve; no stimulation was applied in the control group. Before and for 45 min after, the injection of local anaesthetic touch perception, pin prick, motor strength and skin temperature were tested by a blinded investigator in the areas supplied by the median, musculocutaneous, radial and ulnar nerves. There were no differences in the onset of block between the groups. Thus, the frequency-dependent action of local anaesthetics could not be demonstrated.

Adult↗
PubMed1996

Dacron-covered stent-grafts for the percutaneous treatment of carotid aneurysms: effectiveness and biocompatibility--experimental study in swine.

PURPOSE: To evaluate the short-term effectiveness and biocompatibility of Dacron-covered stent-grafts for percutaneous treatment of carotid aneurysms. MATERIALS AND METHODS: In eight swine, nine aneurysms were created surgically in the common carotid artery. Percutaneous treatment was performed with Dacron-covered stent-grafts. Seven of eight swine underwent follow-up angiography at 2, 3, 4, and 5 weeks after stent implantation. Histologic examinations of tissue from the site of stent implantation were performed at the same intervals. RESULTS: Initial closing off of the aneurysm was possible in all swine. Angiographic follow-up revealed patency of only one Dacron-covered stent-graft after 2 weeks. In six of seven swine, the stent was occluded on the follow-up angiogram. One of the swine died of unclear cause after 1 week. The stent-graft of this swine was not occluded. In all Dacron-covered stent-grafts, inflammatory reaction with granulocyte infiltration was found next to the Dacron material. CONCLUSION: Primary treatment of carotid aneurysms with Dacron-covered stent-grafts is effective. However, the short-term patency rate is poor, which probably can be attributed to the limited biocompatibility of the Dacron cover. An acute inflammatory reaction against Dacron seems responsible for the poor patency rate.

Angiography, Digital Subtraction↗
PubMed1993

[The neuropathy of the autonomic nervous system. An additional anesthetic risk in diabetes mellitus].

Some 20-40% of diabetics suffer from an autonomic neuropathy. This complication of diabetes mellitus impairs the regulation and the reflexes of the cardiovascular system. This study compares the cardiovascular characteristics of diabetics and nondiabetic control patients. METHODS. 21 patients (11 diabetics, 10 nondiabetics) undergoing ophthalmic surgery were investigated. They were tested preoperatively for autonomic cardiovascular dysfunction by application of four established tests. These were: heart rate responses to the Valsalva maneuver, deep breathing and standing up (30/15 test) and the Schellong test. The anaesthesia was induced with fentanyl (0.1 mg), etomidate (2.5 mg/kg) and succinyl choline (1.5 mg) and maintained with oxygen/nitrous oxide (1.4:3 l/min) and isoflurane (0.2-0.8 vol%). Blood pressure and heart rate were automatically measured every minute during induction of anaesthesia and every 3 min during anaesthesia. Additionally the heart rate response to 0.5 mg atropine i.v. was evaluated. RESULTS. The autonomic function tests revealed pathologic reactions in all diabetics (two early, six definitive, three severe) and none in controls. Remarkable cardiovascular events occurred exclusively in the diabetic group, especially during induction of anaesthesia. The systolic blood pressure (SAP) increased in diabetics from a preinduction value of 150 mmHg (median, range 105-205 mmHg) to a maximum of 200 mmHg (160-250 mmHg) after intubation, in controls from 130 (100-150 mmHg) to 170 (110-190 mmHg). Following this peak, SAP fell in diabetics to 120 mmHg (80-160 mmHg), in controls to 110 (100-140 mmHg). Two diabetics had to be treated because of an SAP exceeding 220 mmHg, two other diabetics because of an SAP below 80 mmHg. After atropine administration the heart rate of diabetics showed a median increase of 15% (range 0-40%). In four diabetics, however, the increase was less than 10%. In control patients the increase was 50% (40-80%). All patients with severe cardiovascular reactions during induction of anaesthesia and with heart rate elevation following atropine of less than 10% had a definite or severe neuropathy of the autonomic nervous system revealed by the tests. DISCUSSION. In the only slightly stressful ophthalmic surgery, remarkable events were noted particularly during the induction of anaesthesia. The critical decreases and increases of SAP might be related to the autonomic dysfunction, because of the hypersensitivity of a partly damaged autonomic nervous system or its impaired function. This led to a loss of heart rate variation and adequate blood vessel tone. The severe cardiovascular reactions always went along with clearly pathologic findings in the tests performed. Normal test results in diabetics implied normal cardiovascular reactions, as could be observed in nondiabetics. CONCLUSION. Abnormal cardiovascular reactions in diabetics must be kept in mind. The simple tests specified here can identify such predisposed patients.

Adult↗
PubMed1991

Relation between renal and hepatic excretion of drugs. XIV. Elimination of ioglycamic acid after nephrectomy, bile duct ligation, and after treatment with hormones or xenobiotics in young and adult rats.

Ioglycamic acid (IGA) is effectively eliminated in young and adult rats via urine and bile. After administration of low doses hepatic excretion dominates whereas following high supply renal elimination surpasses biliary excretion. Hepatic transport of IGA is active, indicated by the occurrence of a transport maximum in vivo and by a distinct accumulation of this drug within liver slices in vitro. Renal removal of IGA is preferentially caused by glomerular filtration. A tubular reabsorption obviously does not occur because forced diuresis (mannitol, furosemide) does not increase renal excretion of this substance. As calculated from our clearance data and as a result of accumulation experiments in vitro on renal cortical slices the active tubular secretion of this organic anion can be excluded. In principle there are no qualitative changes in IGA elimination between the 20th and 55th day of life, but active hepatic transport of the drug is significantly lower in young, immature rats. After bile duct ligation, renal excretion of IGA increases distinctly in both age groups, whereas in adult rats bilateral nephrectomy (NX) is followed by a significant decrease in its hepatic excretion in dependence on time after kidney removal. In young rats NX is without consequences on hepatic excretion of IGA. It is possible to stimulate renal and/or hepatic excretion of IGA by repeated administration of T3, dexamethasone, or phenobarbital. The effect of stimulation is different in kidney and liver and depends on age, too.

Animals↗