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Biomedical subjects

Michael Zenz

Publications and source records attributed to Michael Zenz.

17 recordsLinked to original sources
PubMed2006

[Opioids: modern concepts of pain management].

In cancer pain management the application of opioids is established and follows the WHO guidelines. In the management of chronic non-cancer pain opioids are used increasingly but the effectiveness is less. Several central and gastrointestinal side effects can limit the outcome. A careful patient selection is necessary and indications and contraindications must be regarded. The psychomotor performance is not impaired in all patients but must be controlled in the individual patient. In chronic pain management opioids are a component of an interdisciplinary concept and can be used safely by considering therapy rules and supervision.

Analgesics, Opioid↗
PubMed2006

Efficacy of acupuncture for the prophylaxis of migraine: a multicentre randomised controlled clinical trial.

BACKGROUND: Our aim was to assess the efficacy of a part-standardised verum acupuncture procedure, in accordance with the rules of traditional Chinese medicine, compared with that of part-standardised sham acupuncture and standard migraine prophylaxis with beta blockers, calcium-channel blockers, or antiepileptic drugs in the reduction of migraine days 26 weeks after the start of treatment. METHODS: This study was a prospective, randomised, multicentre, double-blind, parallel-group, controlled, clinical trial, undertaken between April 2002 and July 2005. Patients who had two to six migraine attacks per month were randomly assigned verum acupuncture (n=313), sham acupuncture (n=339), or standard therapy (n=308). Patients received ten sessions of acupuncture treatment in 6 weeks or continuous prophylaxis with drugs. Primary outcome was the difference in migraine days between 4 weeks before randomisation and weeks 23-26 after randomisation. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN52683557. FINDINGS: Of 1295 patients screened, 960 were randomly assigned to a treatment group. Immediately after randomisation, 125 patients (106 from the standard group) withdrew their consent to study participation. 794 patients were analysed in the intention-to-treat popoulation and 443 in the per-protocol population. The primary outcome showed a mean reduction of 2 .3 days (95% CI 1.9-2.7) in the verum acupuncture group, 1.5 days (1.1-2.0) in the sham acupuncture group, and 2.1 days (1.5-2.7) in the standard therapy group. These differences were statistically significant compared with baseline (p<0.0001), but not across the treatment groups (p=0.09). The proportion of responders, defined as patients with a reduction of migraine days by at least 50%, 26 weeks after randomisation, was 47% in the verum group, 39% in the sham acupuncture group, and 40% in the standard group (p=0.133). INTERPRETATION: Treatment outcomes for migraine do not differ between patients treated with sham acupuncture, verum acupuncture, or standard therapy.

Acupuncture Therapy↗
PubMed2006

Designing an acupuncture study: the nationwide, randomized, controlled, German acupuncture trials on migraine and tension-type headache.

BACKGROUND: In the nationwide German Acupuncture Trials (GERAC) verum acupuncture, based on Traditional Chinese Medicine (TCM), was to be tested against sham acupuncture for the entities classified in the West as "migraine" (MIG) and "tension-type headache" (TTH). However, there were no generally accepted guidelines on how to perform a consistent verum or sham treatment. OBJECTIVE: To design broadly consensual verum and sham acupuncture treatment protocols for MIG and TTH for the GERAC. METHODOLOGY: Extensive literature study and consultation with acupuncture experts. Personal interviews, both free and structured, e-mail discussions, and phone conferences were used. RESULTS: Broadly consensual acupuncture protocols for MIG and TTH for verum and sham acupuncture were developed. They included semi-standardized point combinations with clearly described point selection rules based on TCM acupuncture diagnoses. A procedure was developed to help ensure homogenous treatment quality in a large multicenter trial. CONCLUSIONS: The GERAC study design allowed acupuncture to be tested in a naturalistic environment. The rigorous study design and the large number of physician investigators guaranteed a high external validity for the results. The results will help determine the significance of Chinese acupuncture in the context of Western medicine for the treatment of MIG and TTH.

Female↗
PubMed2005

Effects of combined administration of vasopressin, epinephrine, and norepinephrine during cardiopulmonary resuscitation in pigs.

OBJECTIVE: Synergistic effects of epinephrine and vasopressin may be of benefit during cardiopulmonary resuscitation. However, cerebral perfusion was decreased when epinephrine was combined with vasopressin compared with vasopressin alone. Although a combined infusion of norepinephrine and vasopressin improves hemodynamic variables compared with norepinephrine alone during sepsis, it is unknown whether norepinephrine in addition to vasopressin and epinephrine changes vital organ perfusion during cardiopulmonary resuscitation. DESIGN: Prospective, randomized animal study. SETTING: : University hospital research laboratory. SUBJECTS: Twenty-one domestic pigs. INTERVENTIONS: After 4 mins of ventricular fibrillation and 3 mins of basic life support, the pigs were randomly assigned to receive either 200 microg/kg epinephrine, 0.4 units/kg vasopressin alone, or 45 microg/kg norepinephrine plus 45 microg/kg epinephrine plus 0.4 units/kg vasopressin before defibrillation. MEASUREMENTS AND MAIN RESULTS: Organ perfusion was determined by radiolabeled microspheres. Myocardial blood flow (mean +/- sem) before and 90 secs and 5 mins after drug administration was 8 +/- 2, 25 +/- 6, and 7 +/- 1 mL/min/100 g after high-dose epinephrine, 12 +/- 1, 75 +/- 7, and 60 +/- 10 mL/min/100 g after vasopressin, and 9 +/- 2, 95 +/- 26, and 46 +/- 15 mL/min/100 g after vasopressin/epinephrine/norepinephrine, respectively (p < .05 at 90 secs and 5 mins vasopressin vs. epinephrine and vasopressin/epinephrine/norepinephrine vs. epinephrine). At the same time points, cerebral blood flow was 8 +/- 2, 23 +/- 3, and 17 +/- 3 mL/min/100 g after epinephrine, 11 +/- 3, 55 +/- 7, and 52 +/- 7 mL/min/100 g after vasopressin, and 11 +/- 4, 67 +/- 13, and 53 +/- 12 mL/min/100 g after vasopressin/epinephrine/norepinephrine, respectively (p < .05 at 90 secs and 5 mins vasopressin vs. epinephrine and vasopressin/epinephrine/norepinephrine vs. epinephrine). Two of seven animals in the epinephrine group, four of seven animals in the vasopressin/epinephrine/norepinephrine group, and seven of seven animals in the vasopressin group could be successfully resuscitated (p < .05 vasopressin vs. epinephrine). CONCLUSIONS: Vasopressin with or without epinephrine and norepinephrine resulted in higher myocardial and cerebral perfusion than epinephrine alone, but there was no benefit in adding norepinephrine to vasopressin and epinephrine with regard to cardiac and cerebral blood flow during cardiopulmonary resuscitation.

Animals↗
PubMed2004

Mean sustained pain levels are linked to hemispherical side-to-side differences of primary somatosensory cortex in the complex regional pain syndrome I.

Chronic back pain as well as phantom-limb pain is characterized by a close relationship between the amount of cortical reorganization and the magnitude of pain. In patients with positively assessed complex regional pain syndrome type I (CRPS I), we found a positive correlation between representational changes of primary somatosensory cortex (SI) and mean sustained pain levels. We investigated seven right-handed patients with CRPS I of one upper limb by means of somatosensory evoked potential (SSEP) mapping. Cortical representation of the CRPS-affected hand was significantly smaller than that of the contralateral healthy hand, giving rise to a substantial side difference. Subjective pain levels experienced over the last 4 weeks were estimated according to the visual analogue scale (VAS). Individual expansion of hand representation contralateral to the CRPS-affected limb was significantly correlated with mean pain intensity. Accordingly, low pain levels were linked to small representational side-to-side differences, while subjects with a distinctive hemispherical asymmetry reported the highest pain levels. Follow-up studies using functional imaging methods might be instrumental in providing a better understanding of this issue.

Adult↗
PubMed2003

Reorganization in the ipsilateral motor cortex of patients with lower limb amputation.

The aim of the present study was to assess reorganization in the motor cortex of patients with lower limb amputation. We studied seven patients with traumatic lower limb amputation, and six healthy controls, using transcranial magnetic stimulation mapping, with recordings from the quadriceps femoris muscle on both sides. Motor threshold, sum of amplitudes, area and the amplitude-weighted centre of gravity (COG) of the motor output map were assessed. We found a significant lateral displacement of the COG on the hemisphere contralateral to the healthy leg, whereas other parameters did not differ significantly between sides. This finding might be indicative of cortical reorganization in the hemisphere ipsilateral to the amputation. It is discussed with respect to an altered peripheral input to this hemisphere, and to transcallosal interactions from the deafferented hemisphere.

Adaptation, Physiological↗
PubMed2003

Efficacy of the NMDA-receptor antagonist memantine in patients with chronic phantom limb pain--results of a randomized double-blinded, placebo-controlled trial.

Phantom limb pain (PLP) associated neuroplastic changes are partly mediated by excitatory amino acids at NMDA receptor sites. This study was undertaken to deduce if NMDA-receptor antagonists may be effective in patients with chronic PLP. Therefore a four week double-blinded, randomized placebo-controlled trial was performed to evaluate the efficacy of 30 mg memantine/day, an orally administrable NMDA receptor antagonist.Thirty-six patients, 18 per group, with a history of at least 12 months PLP and an average pain of at least 4 on the 11-point numeric rating scale (NRS) were enrolled. The patients completed a standardized questionnaire before the trial. PLP intensity and the level of eight complaints were assessed during the trial. Number needed to treat (NNT) was calculated based on the average PLP during the 3rd week (steady state). In both groups, PLP declined significantly in comparison with the baseline (verum: 5.1 (+/-2.1) to 3,8 (+/-2,3), placebo from 5.1 (+/-2.0) to 3.2 (+/-1,46) NRS) without a re-rising of the PLP during the washout period. Mean pain relief was 47% in the memantine group (10 patients reported more than 50% relief), 40% in the placebo group (6>50%): NNT were 4.5 (KI: 2.1-10.6). Analysis of covariance demonstrated a significant impact only on the prior PLP intensity, but no treatment effect. Two patients have demonstrated long-term pain relief under memantine until now (16 months). The total number of slight adverse events were comparable in both groups, but the overall number of severe events was higher in the memantine group (P<0.05). This trial failed to demonstrate a significant clinical benefit of the NMDA-receptor antagonist memantine in chronic PLP. The administration of a higher dosage is probably not tolerable.

Adult↗
PubMed2003

Recommendations for using opioids in chronic non-cancer pain.

1. The management of chronic pain should be directed by the underlying cause of the pain. Whatever the cause, the primary goal of patient care should be symptom control. 2. Opioid treatment should be considered for both continuous neuropathic and nociceptive pain if other reasonable therapies fail to provide adequate analgesia within a reasonable timeframe. 3. The aim of opioid treatment is to relieve pain and improve the patient's quality of life. Both of these should be assessed during a trial period. 4. The prescribing physician should be familiar with the patient's psychosocial status. 5. The use of sustained-release opioids administered at regular intervals is recommended. 6. Treatment should be monitored. 7. A contract setting out the patient's rights and responsibilities may help to emphasize the importance of patient involvement. 8. Opioid treatment should not be considered a lifelong treatment.

Analgesics, Opioid↗
PubMed2003

Fibrinolytic activity and bleeding after cardiac surgery with cardiopulmonary bypass and low-dose aprotinin therapy.

Low-dose aprotinin inhibits hyperfibrinolysis in cardiac surgery. However, excessive postoperative bleeding and increased fibrinolysis may occur despite low dose-aprotinin administration. We investigated (i) whether fibrinolytic activity significantly rises under low-dose aprotinin administration, and (ii) whether this is associated with excessive postoperative bleeding (> or = 1000 ml/24 h). In a prospective single-blind trial, 120 consecutive patients were randomized to receive 280 mg aprotinin or no aprotinin before skin incision. D-dimer levels increased significantly to the end of surgery, reaching higher levels in the control group. The risk for excessive bleeding was lower in the aprotinin group (12 versus 37%, = 0.001). Fifteen minutes after heparin reversal, patients were at risk for excessive bleeding, when enhanced fibrinolysis was documented (aprotinin group, D-dimer > or = 1.0 micro g/ml, odds ratio = 9.1, = 0.047; control group, D-dimer > or = 3.0 micro g/ml, odds ratio = 4.6, = 0.014). Ninety-seven per cent of the aprotinin group and 81% of control group patients had no excessive bleeding when the D-dimer plasma level was below these values. We conclude that (i) fibrinolytic activity significantly rises under low-dose aprotinin administration, and (ii) plasma D-dimer levels at end of surgery may help to identify patients who are unlikely to develop excessive postoperative bleeding.

Adult↗
PubMed2002

Difficult airway management in a patient with severe aortic stenosis, coronary artery disease, and heart failure.

We report a patient with aortic stenosis, coronary artery disease, and heart failure in whom awake fiberoptic intubation was performed because the patient's mouth opening was insufficient as a result of disc prolapse of the mandibular joint. We planned to perform this procedure during conscious sedation, spontaneous respiration, and with stable hemodynamic parameters (no tachycardia, hypertension, or hypotension). After oral premedication with dikaliumclorazepate, the patient received clonidine. Fiberoptic intubation was performed while the patient breathed spontaneously. Throughout the procedure, no adverse events occurred. Clonidine is a valuable adjunct for conscious sedation and can be used safely for sympathicolysis, even in patients with aortic stenosis.

Aortic Valve Stenosis↗
PubMed2001

Quantitative sensory testing, neurophysiological and psychological examination in patients with complex regional pain syndrome and hemisensory deficits.

Based on bed-side neurological testing, it has recently been shown that 33% of chronic complex regional pain syndrome (CRPS) type I patients exhibit sensory impairments, which extend past the painful area of the affected limb in a hemisensory distribution (Pain, 80 (1999) 95). In the present study, the clinically observed changes in touch and temperature sensations on the side of the body ipsilateral to the affected limb were investigated quantitatively. Neurophysiological and psychological examinations were conducted to detect changes in the peripheral and central nervous system as well as psychopathological abnormalities. In 40 patients with CRPS, a bed-side neurological examination was performed. Quantitative sensory testing was conducted at five locations on each side of the body. The evaluation of touch thresholds was performed using von Frey filaments (n=40). To measure cool, warm and heat pain thresholds quantitatively, a thermal stimulator using a Peltier-element was used (n=28). With respect to clinical findings, the initiating trauma and severity of abnormalities on nerve conduction testing, three patients were diagnosed as having a reliable CRPS II (causalgia) and five patients a possible CRPS II. Thirty-two patients were diagnosed as having a CRPS I.On clinical examination, 15 patients revealed generalized sensory deficits on the side of the body ipsilateral to the affected limb (hemisensory deficit, n=12; sensory impairment in the upper quadrant of the body, n=3). Patients with these generalized sensory deficits had a significantly longer illness duration (P<0.05) and a significantly higher percentage of mechanical allodynia/hyperalgesia than patients with spatially restricted sensory deficits (n=25) (P<0.05). In patients with generalized sensory impairment, thresholds for touch, warm and cold sensations, and for heat pain were significantly increased at all five locations tested ipsilaterally compared with the contralateral body side, except for the cool threshold on the chest and the heat pain threshold distally on the affected limb. In patients with sensory deficits limited to the affected limb, the touch threshold was significantly higher only in the distal part of the affected limb when compared with the contralateral limb. In these patients, thermal testing revealed almost no differences in cool, warm and heat pain thresholds when comparing both sides. Repeated thermal testing conducted in five patients with generalized sensory impairment reproduced the significant differences between both sides for cool, warm and heat pain thresholds. However, the correlation between the results obtained in the first and second examinations was poor. Neurophysiological recordings revealed pathological results in 46% for nerve conduction studies, 24% for somatosensory evoked potentials and 39% for sympathetic skin response. For all methods applied, there was no statistically significant difference in the incidence of pathological results between patients with generalized and patients with spatially restricted sensory abnormalities. Psychological examination using the structured clinical interview on DSM-IV (SKID) demonstrated a high frequency of affective and anxiety disorders, however, without significant differences between both groups.We conclude that hemisensory impairment in patients with CRPS Type I is probably related to functional disturbances in processing of noxious events in the thalamus and may be a clinical correlate of subcortical brain plasticity in chronic pain.

Adult↗
PubMed1996

Direct conversion from oral morphine to transdermal fentanyl: a multicenter study in patients with cancer pain.

Direct conversion from oral morphine to transdermal fentanyl with a ratio of oral morphine/transdermal fentanyl (100:1 mg) daily was examined in patients with cancer pain. Patients with a 'stable and low level of cancer pain' receiving a constant dosage of sustained release morphine during a pre-study phase of 6 days were included in the study. Initial fentanyl dosage was calculated by a conversion table. The transdermal system was changed every 72 h and the dosage was adjusted to the needs of the patients according to the VAS scores and the requirement of liquid morphine, which was allowed to achieve sufficient pain relief. Regression analysis at the end of the study revealed a mean morphine/transdermal fentanyl ratio of 70:1. Pain relief during treatment with transdermal fentanyl was identical to sustained release morphine. However, significantly more patients took supplemental medication with liquid morphine during transdermal fentanyl therapy. The number of patients suffering from pain attacks did not increase with transdermal fentanyl. Constipation and medication with laxatives decreased significantly during fentanyl therapy. Other side effects and vital signs were identical. Three patients suffered from a morphine withdrawal syndrome beginning within the first 24 h of transdermal fentanyl therapy. Cutaneous reactions to the patch were rare, mild and transient. Patients and physicians reported satisfaction with the transdermal therapy. 94.7% of the patients chose to continue the transdermal fentanyl therapy at the end of the study due to better performance in comparison to oral morphine. Due to these results an initial conversion from oral morphine to transdermal fentanyl with the ratio of 100:1 is safe and effective.

Administration, Cutaneous↗