Biomedical subjects
Publications and source records attributed to W Dick.
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Clinical studies are usually conceived of as controlled randomized trials, as retrospective patient statistics or as single case reports. However, such a classification is too narrow and overlooks many other forms of study designs. This review, therefore, offers a more encompassing and practical classification of clinical studies for the field of emergency medicine. Randomized controlled trials fulfill scientific criteria at the highest level (gold standard): comparison, repeatability, objective measurement. At the same time, randomized trials also have to comply with demanding ethical criteria and must be justifiable in the individual patient. Therefore, comparable uncertainty with regard to the superiority of the treatment options under investigation is a sine qua non. In addition to randomized trials, six other groups of clinical trials have the potential to solve scientific questions in emergency medicine: observational studies, decision analysis, meta analysis, public health care studies, case reports and descriptive summary statistics and studies on ethical problems. This variability in trial designs calls for a clinically oriented methodologist; the concept and institutionalization of theoretical surgery has been a response to this demand. All study types in this review are illustrated by examples in emergency medicine. Literature for advanced reading in particular trial methodologies can be found in the reference list. A checklist summarizes all elements for designing and conducting randomized trials in emergency medicine. All clinical trials striving for a high standard of quality--whether randomized or not--depend on the following prerequisites:professional organization, time effort, a supportive social environment and a scientific culture.
Epidural anaesthesia is extremely useful in providing postoperative analgesia for children after surgery of the lower body. Although results on early pharmacokinetics in children have previously been reported, no data are available on the long-term effects of epidural anaesthesia. The aim of this investigation was the assessment of plasma bupivacaine levels in children with continuous epidural anaesthesia in the postoperative period. A catheter with an outer diameter of 0.63 mm was inserted through a 19G Tuohy cannula into the epidural space. A maximum dose of 0.4 mg/kg/h bupivacaine was administered for continuous epidural infusion. Careful monitoring was performed to detect early signs of local anaesthetic intoxication. Two milliliters of blood were obtained in each patient per day and nepholometric serum measurement were performed to determine alpha 1-acid glycoprotein and albumin levels. Bupivacaine plasma concentrations were assessed according to the method described by Sattler et al. [25]. Ten children were included in the investigation. The measured albumin and alpha 1-acid glycoprotein concentrations were within the range described by other investigators. At the onset of pain therapy maximum levels of 0.5 microgram/ml were recorded after a loading dose of bupivacaine and levels of up to 2.2 micrograms/ml were achieved following continuous infusion. There were no neurologic complications or signs of local anesthetic intoxication. In conclusion our results show that a dose of up to 0.4 mg/kg/h bupivacaine during continuous epidural infusion is not associated with toxic complications. Careful monitoring of the children by experienced staff is mandatory.
Early defibrillation is the standard of care for patients with ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT). Technical developments aim at further miniaturization and simplification of defibrillators as well as adaptation of energy requirements to the patient's needs. Implantable Cardioverter-Defibrillators (ICD) and automated external defibrillators (AED) are based upon the same technology. Both devices analyze the ECG signal internally, followed by a "shock" or "no shock" decision. Use of automated devices is the prerequisite for defibrillation by non-physicians. Chest impedance measurements and use of alternative shock waveforms, such as biphasic, aim at adaptation of energy or current to the patient's individual needs and avoid application of unnecessarily high amounts of energy to the myocardium. Calculation of median frequency is a non-invasive method for analyzing the heart's metabolic and electrical state. It helps to determine the optimal moment for defibrillation during cardiopulmonary resuscitation (CPR). Developments concerning the structure of in-hospital emergency systems or pre-hospital emergency medical services (EMS) aim at further reductions in time from collapse of a patient until first defibrillation. Such developments include early defibrillation programs for emergency medical technicians (EMT), nurses, and fire or police department first responders as well as wide distribution of easy-to-operate defibrillators in public areas, as discussed during the American Heart Association's Public Access Defibrillation conferences. All programs of that kind have to be organized and supervised by a physician who is responsible for training and supervision of the personnel involved.
A rheumatologic educational program for general practitioners (GPs), based on andragogic principles, has been developed by the study group for Continuing Education and Quality Control of the Association of Cooperative Centers of Rheumatology in the DGRh. The educational program has been tested and evaluated by a study group supported by the German Ministry of Health (FB 2-43346-8/63) as an possible tool for quality assurance in rheumatology. Evaluation was carried out in 2 audit circles each of the KV Hessen and KV Lower Saxony. In the 4 audit circles 39 GPs and 3 trained rheumatologists, acting as "experts", participated. Using didactic materials provided by the study group, the topic "shoulder-neck pain" was discussed in all 4 audit circles. Questionnaires and case records according to the topic were used as evaluation tools. The evaluation was supported scientifically by the Scientific Institute of the German Medical Association (WIAD). Of patients with shoulder-neck pain (1193 pre- and 958 post-education) 2151 records were documented by the participating GPs for the evaluation of outcome in respect of changes of diagnostic and therapeutic attitude. Additionally pre- and postintervention, 10 MC questions related to the topic were used to measure changes in specific knowledge, and at the end of the audit circles participants were asked by questionnaire for acceptance of the educational program. An index of acceptance of 9.6 points (best: 7.0 points, worst: 31.0 points) indicating an excellent acceptance of the educational program by the participating GPs was recorded. The increase in specific knowledge amounted to about 30% in all 4 audit circles. Changes in diagnostic and therapeutic attitudes showed a better specification within the spectrum of diagnoses, a reduction of expensive and not indicated diagnostic procedures (e.g., CT), as well as a reduction in the use of non-adequate therapeutic modalities (e.g., massage, fango, unguenta, and gels) in favor of physiotherapy and mobilisation or local and systemic use of corticosteroids. The results of the evaluation project demonstrate that interactive learning in small groups (audit circles) based on andragogic principles can contribute to a better quality of care of patients with rheumatic diseases. The innovative concept seems to be a well-accepted alternative to formal lectures in postgraduate medical education.
BACKGROUND: The antifibrinolytic efficacy of a high-dose regimen of epsilon-aminocaproic acid (epsilon-ACA) was compared with aprotinin in first-time coronary operations. METHODS: In a prospective, double-blinded, randomized study, 20 patients received high-dose epsilon-ACA (10 g both as a loading and cardiopulmonary bypass priming dose, 2.5 g/h until 4 hours after protamine), and another 20 patients received aprotinin (2 x 10(6) KIU [280 mg] for loading and priming, 0.5 x 10(6) KIU/h [70 mg/h]). Ten untreated patients served as controls. RESULTS: Both agents reduced postoperative levels of thrombin/antithrombin III complexes, D-dimers, fibrin degradation products, free plasma hemoglobin (epsilon-ACA versus aprotinin, p = not significant; p < 0.05 versus controls), and amount of retransfused autologous blood (p < 0.001). Epsilon-ACA increased, aprotinin suppressed antiplasmin-plasmin complex generation (epsilon-ACA versus controls, p < 0.02; epsilon-ACA versus AP, p < 0.0001). For 4 hours after discontinuation, more chest drainage occurred with epsilon-ACA than aprotinin (137 +/- 90 mL versus 62 +/- 29 mL; means +/- standard deviation; p < 0.02). Cumulative 12-hour drainage was similar for aprotinin (391 +/- 220 mL) and epsilon-ACA (582 +/- 274 mL), but higher without inhibitor (1,091 +/- 541 mL; p < 0.001 versus drugs). Postoperatively, aprotinin was associated with the lowest autologous retransfusion incidence and highest hematocrits (p < 0.01 versus epsilon-ACA). Homologous transfusion exposures did not differ. CONCLUSIONS: In first-time coronary operations, higher postoperative hematocrit and less shed blood retransfusion constitute only subtle advantages of aprotinin over high-dose epsilon-ACA.
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OBJECTIVE: To compare the metric properties and validity of German versions of the WOMAC (Western Ontario and McMaster Universities) and a self-administered questionnaire-format of the Lequesne-Algofunctional-Index in patients with osteoarthritis (OA) of the lower extremities. DESIGN: Cross-sectional analysis of the instruments' internal consistency (Cronbach's coefficient alpha) and construct validity (correlation with radiological OA-severity and limitation in range-of-motion) in ambulatory patients and patients before hip arthroplasty. Test-retest reliability was assessed on a subsample after 10 days. RESULTS: Data from 51 patients out of 91 contacted could be analyzed. Twenty-nine patients had knee and 22 patients had hip OA. Both the WOMAC and Lequesne OA-indices and their scales or sections had a satisfactory test-retest reliability (Intraclass correlation coefficient 0.43-0.96). All scales of the WOMAC were internally consistent (Cronbach's coefficient alpha 0.81-0.96) and associated with radiological OA-severity and joint range of motion. However, only the function but not the symptom sections (Cronbach's coefficient alpha knee: 0.55; hip: 0.63) of the self-administered Lequesne OA index were internally consistent for both, patients with knee and hip OA. Also, the symptom components were not or only weakly associated with radiological OA-severity and joint range of motion. CONCLUSIONS: Although our results are based on a German version using a self-report format we may caution using the self-administered Lequesne OA index without prior testing of its metric properties and validity.
In a prospective, randomized, double-blind, placebo-controlled, multicentre study, the efficacy of prophylactic tropisetron (2 mg) or ondansetron (4 mg) for the prevention of post-operative nausea and vomiting after abdominal or non-abdominal surgery with general balanced anaesthesia was studied in 842 ASA I-III patients. In patients undergoing abdominal surgery, ondansetron and tropisetron reduced the frequency of emetic episodes compared with the placebo (29%, 30% vs. 42% respectively). In men, neither tropisetron nor ondansetron had an effect different from the placebo, whereas in women both drugs led to lower rates of emetic episodes and nausea. In comparison with abdominal surgery, fewer patients in the non-abdominal surgery subgroup had emetic episodes (42% vs. 23% in the placebo group). However, neither tropisetron nor ondansetron was significantly different from the placebo in this patient subgroup. In conclusion, for patients at increased risk of post-operative nausea and vomiting, a prophylactic therapy at the lowest effective dose with tropisetron or ondansetron may be useful.
Epidermolysis bullosa hereditaria dystrophica (Hallopeau-Siemens) is a rare autosomal recessive disease characterized by extreme bullae formation of skin and mucosa. Typical dystrophic nails and flexion contractures of the joints can lead to deformities. Carious teeth and microstomia caused by scarred contractures of the lips are characteristic of the clinical picture. Depending on the form and severity of epidermolysis bullosa, the anaesthetic and surgical management requires careful planning to avoid unnecessary complications as a result of positioning, anaesthesia or surgery. In cooperation with the patient, optimal positioning on the operating table without pressure or tangential friction of the skin needs to be achieved. Wherever possible, surgical tape and adhesive electrodes should be avoided. Artificial respiration, intubation and monitoring must be adapted to the skin conditions of the patient. In particular the skin below the blood pressure cuff must be protected by adequate padding, and maximum intervals between measurements should be chosen. Nasal, oral, laryngeal and tracheal manipulations should be kept to a minimum for protection of the upper airway. Fibre optic intubation is to be preferred because of the possibility of microstomia and the need for simultaneous airway diagnosis. In addition, oro- or nasopharyngeal tubes and catheters should be avoided where possible. Depending on the course of surgery and anaesthesia, postoperative therapy in an intensive care unit should be considered.
Risk research and risk analysis have to be modeled as a fairly complex system including multivariate regression modeling for risk factors in etiology, Markov models in pathogenesis, and a construct of mechanistic and hermeneutic variables for clinical outcome analysis. The McPeek index is proposed as an example. Several prophylaxes for risk reduction in the perioperative period produce risk reduction as well as risk augmentation in different types of outcome. These unexpected findings were observed not only in clinical trials, but also in animal experiments and in isolated tissues. This demonstrates a basic problem of handling complexity in the real clinical setting.
BACKGROUND: Improved cardiopulmonary circulation with active compression-decompression resuscitation (ACD-CPR) has been demonstrated in studies using different animal models and a small number of human in cardiac arrest (CA). However, prehospital studies have shown both positive and no extra benefit of ACD-CPR on survival rates and neurologic outcome. MATERIAL AND METHODS: The aim of our prospective study was to compare standard manual CPR (S-CPR) to ACD-CPR as the initial technique of resuscitating patients with out-of-hospital CA with respect to survival rates and neurological outcome in our two-tiered EMS system with physicians in the field. RESULTS: Patients with out-of-hospital CA treated by emergency medical services (EMS) personnel were randomly assigned to 1 of 2 groups (ACD-CPR versus S-CPR). The treatment groups were similar with respect to age, sex, time interval from collapse to CPR, defibrillation and first epinephrine medication. There was no difference between the ACD group and the standard CPR group in terms of survival rates and neurologic outcome. No differences occurred concerning complications of CPR. CONCLUSION: In our two-tiered EMS system with physician-staffed ambulances ACD-CPR neither improved nor impaired the survival rates and the neurological prognosis in patients with out-of-hospital cardiac arrest. Our results are in accordance with other studies carried out in EMS systems, with first tier call-response intervals between 4 and 6 min.
UNLABELLED: We performed a prospective multi-center study in order to determine the causes of 30-day perioperative mortality. METHODS: In accordance with the CEPOD-Study and with the kind permission of Dr. N. Lunn, we forwarded two different questionnaires to 135 hospitals. One questionnaire was to be answered by the anaesthetist and the other one by the surgeon involved in cases o perioperative death within the first 30 days after the operation. 12 out of 135 addressed hospitals agreed to participate in the study. These included four small hospitals, six medical centres of medium capacity (about 500 beds) and two University hospitals. In order to obtain an exact description of the events leading to perioperative death, the questionnaires consisted of approximately 60 questions for the collection of demographic data and the surgical as well as anaesthesiological perioperative management. RESULTS: From 1989 to 1993 more than 300 cases of perioperative death were reported. Only 200 cases could be analyzed due to incompletely answered or unreturned questionnaires. The mean risk-classification (ASA) was 3.46, mean age 74.6 years. Approximately 40 percent of deaths occurred in patients older than 80 years. More than 80 percent of patients had at least one pre-existing cardiovascular disease with prevalence of 41% for pulmonary and gastrointestinal diseases. In the majority of cases abdominal operations were performed, followed by hip-surgery and surgery of the aorta. In 86% of the cases, the surgeon was experienced and had performed the respective operation more than 20 times. In 38.2% an anaesthetist in training was responsible for anaesthesia, but only 11.6% were without supervision of a specialist anaesthetist. The majority of patients received general anaesthesia (78%) and 8.5% had a combination of EDA and general anaesthesia. Regional anaesthesia was performed in 12.5%, local anaesthesia in only 1%. The average blood loss was approximately 1.600 ml (with a very wide range) and 42.5% of the patients needed a transfusion of blood components, primarily in the form of packed red blood cells. Seventeen serious incidents occurred intraoperatively, including three "exitus in tabula". Four patients died shortly after the operation in the ICU, the other ten incidents were managed in the operating room. In 11 of 17 incidents the patients suffered a cardiac arrest; nine patients were resuscitated. Two patients were not resuscitated in view of pre-existing diseases and inoperability. All of the hospitals had an ICU for postoperative care, but two of the smaller hospitals had no recovery rooms. In 22 cases of emergency operations, there was a delay due to a lack of personnel or to logistic problems. In five of these cases, the delay was described as a possible cofactor of perioperative mortality. The most frequent causes of perioperative death were myocardial failure (33.7%) and multi-organ-failure (19.2%), followed by respiratory insufficiency (13%) and septic shock in 9.3%. A necropsy was carried out in only 28 of 200 perioperative deaths (14%); 13% of the cases were discussed in a surgical and only 2.5% in an anaesthesiological mortality-conference. In 9 out of 12 hospitals no mortality-conferences were held. All surgeons and anaesthetists were asked for self-assessment on the basis of an analog scale ranging from 0 and 10 points. The average score was 8.52 points (surgical management) and 9.36 points (anaesthesiological management respectively), which is not always in correspondence with the information provided in the questionnaires. CONCLUSIONS: In order to further reduce perioperative mortality in critically ill patients, every hospital should aim to optimize the structure of the surgical and anaesthesiological departments. A delay due to logistical or personnel problems may be a co-factor in perioperative mortality. Recovery rooms with experienced personnel should be the standard in postoperative anaesthesiological care. (ABSTRACT TRUNCATED)
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The deformity in severe spondylolisthesis consists of two components: the parallel anterocaudad slip of the spondylolisthetic vertebra, and its tilt into kyphotic malposition. The influence of the two components is very different: the anterocaudad slippage has not much impact on the sagittal profile of the spine and is easily compensated for by a slight increase in lumbar lordosis. The kyphotic deformity has a high impact on trunk imbalance and the sagittal profile. There are two compensation mechanisms: hyperlordosis of the lumbar spine to its anatomical extremes and-if that is not sufficient-verticalisation of the sacral bone, performed by contracture of the hamstrings and uprighting of the pelvis around the hip joints. The latter mechanism is followed by functional disadvantages. Therefore, correction of the kyphosis of L5 may be considered during operative treatment if the lumbosacral kyphosis (angle delta) is less than 85 degrees and the sacral inclination less than 35 degrees.
In a prospective, randomized, placebo-controlled, double-blind trial we tested the hypothesis that naloxone given during cardiopulmonary resuscitation (CPR) enhances cerebral and myocardial blood flow. Twenty-one anesthetized, normoventilated pigs were instrumented for measurements of right atrial and aortic pressures, and regional organ blood flow (radiolabeled microspheres). After 5 min of untreated fibrillatory arrest, CPR was commenced using a pneumatic chest compressor/ventilator. With onset of CPR, an i.v. bolus of 40 micrograms/kg b.w. of epinephrine was given, followed by an infusion of 0.4 micrograms/kg per min. After 5 min of CPR, either naloxone, 10 mg/kg b.w. (group N, n = 11) or normal saline (group S, n = 10) was given i.v. Prior to, and after 1, 15, and 30 min of CPR, hemodynamic and blood flow measurements were obtained. After 30 min of CPR, mean arterial pressure was significantly higher in group N (26 +/- 5 vs. 13 +/- 3 mmHg, P < 0.05). Groups did not differ with respect to myocardial perfusion pressure or arterial blood gases at any time during the observation period. Regional brain and heart blood flows were not different between N and S at any point of measurement. We conclude that high-dose naloxone does not augment cerebral or myocardial blood flow during prolonged closed-chest CPR.