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Biomedical subjects

M Zenz

Publications and source records attributed to M Zenz.

At least 37 records · Page 2Linked to original sources
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

Assessment of reorganization in the sensorimotor cortex after upper limb amputation.

OBJECTIVE: We wanted to investigate plastic changes occurring in the motor and somatosensory cortex after upper limb amputation, and their possible relationship to phantom pain. METHOD: To assess these plastic changes, we used transcranial magnetic stimulation (TMS) and source localization of somatosensory evoked potentials (SEP). Eleven patients with upper limb amputation were investigated. The phantom pain intensity was assessed by visual analogue scaling (VAS). RESULTS: Using TMS mapping, we found a significant lateralization of the amplitude-weighted centre of gravity (P<0.01) and an enlargement of the excitable area (P<0.05) on the hemisphere contralateral to the amputation. SEP mapping showed a significant medialization of the N20 dipole (P<0.05) on this side. None of these changes correlated with the phantom pain intensity. CONCLUSIONS: We conclude that after limb amputation, the relationship between plastic changes occurring in the sensorimotor cortex and phantom pain seems to be more complex than previously believed.

Adult↗
PubMed2000

Changes of cortical excitability in patients with upper limb amputation.

In our study we wanted to assess motor excitability in patients with upper limb amputation by means of transcranial magnetic stimulation (TMS). In 12 patients, TMS was applied using a paired pulse paradigm in order to test cortico-cortical excitability. Additional parameters of motor excitability like motor threshold and cortical silent period were also measured. Recordings from the amputated side were compared to the contralateral side and to healthy controls. We found a significant reduction of intracortical inhibition in forearm amputees and an enhancement of intracortical facilitation in upper arm amputees on the affected side. We conclude that after upper limb amputation, changes in the activity of intracortical interneuronal circuits appear in the affected hemisphere. These changes may depend on the level of amputation, and be the base of cortical reorganization.

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↗
PubMed2000

[Epidemiology of chronic pain - an investigation in 5 medical practices].

BACKGROUND AND METHODS: The aim of this study was to get more information about the prevalence of chronic pain in different practices of home physicians. 900 patients of five different specialists (general medicine, internal medicine, neurology, orthopaedics, surgery) in the german town Bochum were investigated with a questionnaire about chronic pain. Chronic pain was defined as a continuous or intermittend pain of longer duration than six months. RESULTS: 36% (328 patients) of all investigated patients had chronic pain due to this definition, twice more women than men. The four most frequent localisations of chronic pain were the back, the head, the joints and the legs. 15% of the patients with chronic pain were retired or going to retire due to their chronic pain. Orthopaedics were the most frequent physicians visited in the past. Only 5% of the patients had a psychological therapy and only 1% were treated in a pain clinic. The primary treatment strategies of the chronic pain were physiotherapy and drug therapy. 30% of the patients did not have any pain relieve by the past treatment strategies. CONCLUSION: Patients with chronic pain are a frequent and important problem in practices of home physicians. The high frequency of patients with chronic pain in practices of specialists demonstrates the necessity of a special qualification also on this level of our medical system.

English Abstract↗
PubMed2000

Coronary artery plaque disruption as cause of acute myocardial infarction during cesarean section with spinal anesthesia.

A 31-year-old parturient delivered twins at 35 weeks' gestation by cesarean section with spinal anesthesia. Following anesthesia induction, hypotension and bradycardia occurred, and were immediately treated with theodrenaline plus cafedrin (Akrinor) and atropine. Blood pressure and heart rate increased to 180/100 mmHg and 140 beats per minute, respectively. Several minutes later, the patient developed a myocardial infarction (MI) that she survived after intensive care treatment without sequelae. Although the coronary angiography showed normal coronary vessels, an intravascular ultrasound study demonstrated an atheroma in the left main coronary artery with ruptured fibrous cap. Laboratory screening for risk factors of coronary artery disease (CAD) showed hypercholesterinemia, increased factor VII activity, and hyperfibrogenemia. Angiographically normal coronary vessels are frequently found in pregnant patients who suffered MI. In these patients, coronary spasms have been discussed as the major mechanism of disease. Our case demonstrates that a significant CAD may be present despite angiographically normal findings. Plaque rupture was triggered by hypertension and led to MI as the first symptom of disease. On the basis of these findings, we believe that MI during pregnancy is more often caused by plaque rupture than may be expected, according to the current literature.

Acute Disease↗