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Biomedical subjects

W Dick

Publications and source records attributed to W Dick.

At least 91 records · Page 5Linked to original sources
PubMed1995

Development of a HPLC-system for quantitative measurement of lidocaine and bupivacaine in patients plasma during postoperative epidural pain therapy.

A HPLC method was developed for the simultaneous quantitative analysis of lidocaine and bupivacaine in plasma, with bupivacaine serving as the internal standard for the assessment of lidocaine and vice versa. The samples are prepared by diethyl ether-extraction of the alkalified plasma and re-extraction using diluted sulphuric acid. This allows the elimination of interfering medication and plasma proteins. The prepared samples are chromatographed with a Merck LiChroCART Superspher 60 RP-select B cartridge column, the local anesthetics are detected using UV-photometry and the concentration is calculated by comparing the peak areas of the analyzed substance and the internal standard. Using a sample volume of 1 ml plasma, concentrations of approximately 2.5 micrograms/ml and 1 microgram/ml can be analyzed with a 95%-confidence interval of 2.5% or 5%, respectively. At higher or lower concentrations, accurate results can be obtained using smaller or larger plasma samples. The evolved analytical method allows the rapid and simple determination of lidocaine and bupivacaine plasma levels at a wide range of concentrations. It is suitable for research purposes as well as for routine analyses.

Analgesia, Epidural↗
PubMed1994

Incidence and clinical importance of perioperative histamine release: randomised study of volume loading and antihistamines after induction of anaesthesia. Trial Group Mainz/Marburg.

Although histamine release is recognised as a common event during anaesthesia and surgery, few clinicians judge the resultant cardiorespiratory disturbances serious enough to warrant prophylaxis with antihistamines. We have assessed the incidence and importance of histamine release in a randomised 2 x 2 factorial study. 240 patients representing a routine throughput of major general surgery were studied during a standardised induction of anaesthesia and preoperative loading of the circulation with either Ringer solution or Haemaccel-35, with or without antihistamine prophylaxis with dimetindene (H1) plus cimetidine (H2). Cardiorespiratory disturbances were graded as detectable, clinically relevant, or life-threatening from observers' records of the anaesthesia and the actions taken by the anaesthetists. Disturbances that were accompanied by significant rises in plasma histamine were further designated histamine-related, and those that were not were designated histamine-unrelated. Anaesthetists, observers, and designators were blinded to whether or not the patients had received antihistamines and to which solution was used for circulatory volume loading. Clinically relevant or life-threatening histamine-related disturbances occurred in 8% of the patients who after induction of anaesthesia received Ringer without antihistamines, in 26% of those who received Haemaccel without antihistamines, and in 2% or less of those who received antihistamines (p < or = 0.0001). There were 4 life-threatening histamine-related disturbances, all in patients who received Haemaccel without antihistamines (p < 0.01). Histamine-unrelated disturbances occurred in 16% overall, with no obvious effect of Haemaccel or antihistamines. The histamine-related disturbances under anaesthesia were remarkable for their severity (even with small rises in histamine concentrations), for the prevalence of bradycardia, and for the absence of skin signs. Their likelihood and severity were increased in patients with tumours. The results of the trial make a case for routine prophylaxis with antihistamines as part of anaesthetic management.

Adolescent↗
PubMed1994

Experiments on the possible role of leeches as vectors of animal and human pathogens: a light and electron microscopy study.

The presence and survival of pathogens inside the gut of leeches were studied by means of light and electron microscopy. In African leeches from Cameroon, blood was serologically positive for human immunodeficiency virus (HIV) and hepatitis B; blood of Hirudo medicinalis bought in German pharmacies contained up to 11 different species of bacteria. In experiments done at low (3 degrees C) and high (22 degrees, 32 degrees C) temperatures, it was shown that ingested red and white blood cells survive for long periods. The time was prolonged to at least 6 months in cases in which the leeches were stored at 3 degrees C. The same effect occurred with pathogens. Bacteriophages (viruses of bacteria) and bacteria persisted in large numbers for at least 6 months in the gut of experimentally infected leeches. Protozoan parasites such as Toxoplasma gondii, Trypanosoma brucei brucei, or Plasmodium berghei were even capable of reproducing inside the gut of the leech. In the case of Plasmodium parasites, this proceeded at low (3 degrees C) and high (22 degrees C) temperatures until all erythrocytes were used up. These parasites survived as long as the erythrocytes and lymphocytes were of good shape, i.e., around 5-6 weeks p.i. Single stages survived longer, especially at low temperatures. However, electron microscopy studies gave no hint of penetration of such pathogens into the unicellular salivary glands, which would initiate a direct transmission. Such transmission, however, is possible--many fish leeches directly transmit several blood parasites--when the leeches are squeezed during skin attachment or when they are manipulated by dropping salt solution on their backs while they are sucking. Consequently, the leech is a potential vector of many pathogens, especially in regions with an endemic spread of human and/or animal pathogens.

Animals↗
PubMed1994

[Scoring systems in emergency medicine?].

The primary goals of scoring in emergency medicine are grading of the severity of the patient's condition, measurement of diagnostic and therapeutic efforts, forecasting the outcome, and support in decision making on triage and therapy. Scores can also be used as tools for measuring efficacy and controlling quality. There has been less experience with use of scoring systems to estimate quality of life. The ability to make a prognosis in an individual case is the most critical point; a score may support decisions on therapy in very specific situations only. Scores for use in emergency medicine should be based on physiological parameters, universally applicable and suitable for use throughout the course of diseases. Appropriate score systems are the Glasgow Coma Scale, the Rapid Acute Physiology Score, and the Mainz Emergency Evaluation Score, Trauma Score and Injury Severity Score. Scores suitable for estimation of quality of life following emergencies are the Glasgow Outcome Scale and the Glasgow-Pittsburgh Scale.

Emergency Medicine↗
PubMed1994

[Initial defibrillation by emergency physicians or by first aid assistants? A prospective, comparative multicenter study in outpatients with ventricular fibrillation].

In a controlled prospective randomized study, defibrillation by emergency medical technicians (EMTs) was compared with the current standard of care in Germany (basic life support by EMTs and defibrillation by emergency physicians only) in order to answer the following questions: 1. Does EMT defibrillation improve the survival rate and long-term prognosis of patients in ventricular fibrillation as compared to the current German standards in resuscitation (basic life support by EMTs and defibrillation by emergency physicians)? 2. Are the prerequisites for the use of semiautomatic defibrillators fulfilled in the emergency medical systems (EMS) of the participating centers? METHODS. The study phase includes randomization of 121 adult patients with witnessed cardiac arrest and ventricular fibrillation (VF) as first ECG rhythm. Prior to the onset of the study, all EMTs of the participating EMS systems were retrained in basic life support (BLS) measures. In each center, randomly assessed EMT-Ds (EMTs trained in Defibrillation) were trained to use semiautomatic defibrillators. With the help of one-line tape recording, the time intervals during resuscitation and treatment steps were evaluated. Successfully resuscitated patients were followed up with the help of the Glasgow Coma Scale and the Pittsburgh Cerebral and Overall Performance Categories. RESULTS. From 1 February 1991 until 28 June 1992, 159 patients with VF were randomized. In 121 cases, collapse was witnessed. 25% (14/57) of the patients receiving defibrillation by EMT-Ds (study group = S) were discharged from the hospital alive. In the control group, 52 patients were defibrillated by emergency physicians, following BLS by EMTs [control group 1 = C1; discharged: 29% (15/52)]. Fifty patients received BLS and advanced cardiac life support (ACLS) by the emergency physicians crews [control group 2 = C2; discharged: 18% (9/20)]. In the study group, the median time interval from collapse of the patient until initiation of BLS measures was 7.7 min, 7 min in C1 and 8 min in C2. ACLS measures were initiated significantly earlier (P < 0.05) in the control groups, as compared to the study group [S: 13 min, C1: 11 min; C2: 10.3 min]. Sixty-seven percent (30/45) of the study patients and 46% (36/76) of the control patients were defibrillated within 12 min. Study patients were defibrillated earlier (P < 0.05) (S: 9.9 min; C1: 12.2 min; C2: 12.75 min); return of spontaneous circulation (ROSC) was achieved earlier (P < 0.05) in the study group [S: 14 min; C1: 19 min; C2: 18.2 min] and the number of patients in the study group requiring no epinephrine during resuscitation was higher (P < 0.01) than in the control groups [S: 35.3% (12/34); C1: 10% (4/40); C2: 10.5% (4/38)]. Furthermore, the total amount of epinephrine [mean (+/- standard error)] administered in the study group [S: 2.35 (+/- 0.49) mg; C1: 6.71 (+/- 0.98) mg; C2: 7.71 (+/- 1.31) mg] was significantly lower (P < 0.05). No significant differences in neurological long-term prognosis were found for the groups investigated. CONCLUSION. Neither the initial survival rate the number of patients discharged alive, nor the neurological long-term prognosis was significantly different for any of the groups investigated. Because of apparent differences in indirect prognostic parameters (time interval until ROSC, number of patients requiring no epinephrine) and because of the fact that the time interval to the first defibrillation was reduced by EMT defibrillation, EMT-Ds may perform defibrillation if: (a) they reach the patient before the emergency physician and (b) if they are trained intensively and supervised continuously. In order to increase the efficiency of defibrillation by EMT-Ds, far-reaching changes in our EMS are mandatory: (a) a reduction in the time interval from collapse until initiation of BCLS measures by intensifying layperson CPR training; (b) an increase in the number of emergency units equipped with semiautomatic defibril

Electric Countershock↗
PubMed1994

[Analysis of requests for help. Emergency calls to the fire department and emergency medical services, as well as to the general medical practitioners' emergency services in a rescue service area].

There is no doubt that a single emergency phone number is desirable, but in contrast to other countries, in Germany different emergency phone numbers and dispatching centers exist for the fire brigade (FB), the emergency medical service system (EMS), and the general practitioners' emergency service (GPS). Due to this fact, valuable time is often wasted by connecting or transferring emergency calls from one dispatching center to another. The purpose of this study was to analyse all calls received by the different dispatching centers in the city and county area of Mainz with respect to total number, fraction of emergency calls, and specificity. Further, the total number of calls potentially referring to a hypothetic single dispatching center with a general emergency phone number (112) was calculated. During a 4-month period, all telephone calls were registered and related to day, time, and origin of the call (city or county) and classified as non-urgent or emergency calls, calls appropriate to the dispatching center dialed, emergency calls to be transferred, or unspecific calls. A total of 80,987 calls were received (city area 84.3%, county area 15.7%), most of them directed to the FB of Mainz (33,086). The EMS dispatching center received 31,286 calls, the five GPS-centers 15,256 calls; 1359 emergency calls that were directed to the police or FB needed transfer to the EMS. During weekdays the EMS and FB received the most calls, with a reduced frequency on Saturdays and Sundays (Table 2). Nevertheless, the highest total numbers of calls were received on Saturdays due to multiple calls directed to the GPS.(ABSTRACT TRUNCATED AT 250 WORDS)

Emergency Medical Service Communication Systems↗
PubMed1994

[Different opioids in patients at cardiovascular risk. Comparison of central and peripheral hemodynamic adverse effects].

Efficient analgesia may be the major objective in the cardiovascular risk patient following myocardial infarction, acute occlusion of peripheral vessels, or dissection/perforation of major abdominal vessels. It was the purpose of the study to investigate the haemodynamic and respiratory side effects of eight different opioids in 57 circulatory risk patients prior to major vascular surgery. METHODS. Patients were randomly allocated to eight groups, each receiving a different opioid within a clinical, equipotent dose range (buprenorphine, fentanyl, morphine, nalbuphine, pentazocine, pethidine, tramadol, alfentanil). A complete haemodynamic and blood gas status was obtained prior to as well as 5, 10, 15, and 20 min following opioid administration. Monitoring included a complete invasive haemodynamic and blood gas status. Statistical evaluation was performed by 1- and 2-factorial ANOVA (P < 0.05). RESULTS. Significant time effects (changes from baseline at the time of measurement) were observed for heart rate and total peripheral resistance, while significant group (group-specific differences in the course of values at the different times of measurements) and time effects were noted for mean pulmonary artery pressure, pulmonary capillary wedge pressure, stroke volume index, and PaO2. No major effects were observed following morphine, fentanyl, alfentanil, tramadol, and nalbuphine. Buprenorphine caused distinct respiratory depression accompanied by an increase in pulmonary vascular tone. Pentazocine and pethidine caused a significant increase in MPAP and peripheral vascular resistance while pethidine also produced marked respiratory depression. CONCLUSIONS. For interpretation of the results, factors such as respiratory depression, histamine release, secretion of endogenous catecholamines, and hypoxia-induced pulmonary vasoconstriction have to be discussed. Tramadol, an opioid with moderate potency, seems to offer some advantages due to its minor cardiovascular and respiratory side effects.

Aged↗
PubMed1994

Early defibrillation by emergency physicians or emergency medical technicians? A controlled, prospective multi-centre study.

UNLABELLED: In a controlled, prospective multi-centre study, defibrillation by emergency medical technicians (EMTs) was compared with the current standard of care in Germany--defibrillation by emergency physicians (EPs)-in order to answer the following questions: can EMTs in a two-tiered emergency medical services (EMS) system with physicians in the field defibrillate earlier than, and as safely as EPs? Does defibrillation by EMTs (study group) affect survival rate and long-term prognosis of patients in ventricular fibrillation (VF), as compared with the current national standards in resuscitation (basic cardiopulmonary resuscitation (CPR) by EMTs, and defibrillation by physicians: control group? METHODS: Prior to the onset of the study, all EMTs completed retraining in basic life support (BLS). Randomly assessed EMTs were then trained to use semi-automatic defibrillators. With the help of on-line tape recordings, the complete resuscitation sequence was evaluated. Follow-up of the patients was carried out with the help of the Glasgow Coma Scale as well as Pittsburgh Cerebral and Overall Performance Categories. RESULTS: A total of 159 patients with VF were included in the study. In 121 cases, collapse was witnessed. Of the patients receiving defibrillation by EMTs 25% were discharged from hospital alive, compared to 24% of the patients defibrillated by EPs. Of the study patients 67% were defibrillated within 12 min, while the percentage of control patients was 46%. Study patients were defibrillated earlier (P < 0.01), the return of spontaneous circulation (ROSC) was achieved earlier (P < 0.05), and the rate of patients requiring no adrenalin during resuscitation was higher in the study group (P < 0.05). The total amount of adrenalin administered in the study group was lower (P < 0.05). No statistically significant differences were found concerning the neurologic long-term prognosis. CONCLUSIONS: In our study, EMT defibrillation was equally effective as defibrillation by EPs, but failed to improve survival rates or long-term outcome of patients in VF significantly, compared to EP defibrillation. Due to a reduction in the time intervals from collapse to defibrillation and to ROSC, as well as in adrenalin doses, by EMT-defibrillation, EMTs in Germany should defibrillate if they reach a patient prior to an EP, provided they have received continuous medical training and supervision.

Cardiopulmonary Resuscitation↗
PubMed1994

Quality of on-site performance in prehospital advanced cardiac life support (ACLS).

UNLABELLED: The aim of our prospective study was to assess the structural and procedural quality of an urban emergency medical services (EMS) system providing prehospital basic and advanced cardiac life support (BLS/ACLS), to compare the onsite performance of physicians and non-physicians in ECG diagnosis and defibrillation, and to identify incidence and causes of avoidable delays in the initial treatment sequences. METHODS: Between 1 February 1991 and 1 July 1992, 162 on-line tape recordings of prehospital cardiopulmonary resuscitation (CPR) efforts performed by the staff of the EMS system of the city of Mainz were evaluated. After arrival at the patient's side, time intervals to initial ACLS steps (first ECG-diagnosis, first defibrillation, endotracheal intubation, first epinephrine administration) were measured. Times to rhythm identification and countershock by EMT-Ds vs. physicians were compared (Mann-Whitney U-test). Time intervals are presented as median values. One-hundred sixty-two adult patients with out-of-hospital cardiac arrests (ventricular fibrillation [VF] or ventricular tachycardia [VT], 72; asystole or electromechanical dissociation [EMD], 90) receiving CPR by EMTs, EMT-Ds, and physicians of the Mainz EMS were included. Patients with arrests due to non-cardiac aetiologies were excluded. RESULTS: After arrival at the patient's side, for patients with VF/VT, the EMT-Ds took 1:36 min and the physicians took 1:00 min to obtain the first ECG diagnosis (P = 0.004). The first countershock was delivered within 1:42 min by both EMT-Ds and physicians of the mobile intensive care unit (MICU). After diagnosis was established, the EMT-Ds took 0:08 min to defibrillate, whereas the physicians took 0:36 min (P = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiopulmonary Resuscitation↗
PubMed1994

[Structure, organization and capacity problems in emergency medical services, emergency admission and intensive care units].

Emergency medicine is subjected worldwide to financial stringencies and organizational evaluations of cost-effectiveness. The various links in the chain of survival are affected differently. Bystander assistance or bystander CPR is available in only 30% of the emergencies, response intervals--if at all required by legislation--are observed to only a limited degree or are too extended for survival in cardiac arrest. A single emergency telephone number is lacking. Too many different phone numbers for emergency reporting result in confusion and delays. Organizational realities are not fully overcome and impair efficiency. The position of the emergency physician in the EMS System is inadequately defined, the qualification of too many emergency physicians are unsatisfactory. In spite of this, emergency physicians are frequently forced to answer out-of-hospital emergency calls. Conflicts between emergency physicians and EMTs may be overcome by providing both groups with comparable qualifications as well as by providing an explicit definition of emergency competence. A further source of conflict occurs at the juncture of prehospital and inhospital emergency care in the emergency department. Deficiencies on either side play a decisive role. At least in principle there are solutions to the deficiencies in the EMSS and in intensive care medicine. They are among others: Adequate financial compensation of emergency personnel, availability of sufficient numbers of highly qualified personnel, availability of a central receiving area with an adjacent emergency ward, constant information flow to the dispatch center on the number of available emergency beds, maintaining 5% of all beds as emergency beds, establishing intermediate care facilities. Efficiency of emergency physician activities can be demonstrated in polytraumatized patients or in patients with ventricular fibrillation or acute myocardial infarction, in patients with acute myocardial insufficiency and other emergency clinical pictures. Cost effectiveness is clearly in favor of emergency medicine. Future developments will be characterized by the consequences of new health care legislation and by effects of financial stringencies on the emergency medical services.

Education, Medical, Graduate↗
PubMed1994

[Surgical treatment of the degenerative lumbar spine in ild age].

Degenerative lumbar spine conditions, mostly combinations of spinal stenosis, instability, deformity and arthrosis, threaten the independence of elderly patients due to intractable pain and loss of function. Comprehensive operative treatment is possible, but is often not offered to these patients. The reasons are: fear of an unsuccessful outcome, fear of fatal complications and underestimation of the remaining life span. The literature shows that good results can be obtained in approximately 80% as well in one- and two-level degenerations as in multisegmental deformities. Perioperative mortality is about zero, but the the costs are high, approximately twice as much as for a total hip replacement. The single most frequent complication in 50 patients over 70 years was temporary cerebral problems. With adequate precautions the gain in quality of life outweighs the risks and costs.

Aged↗