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Biomedical subjects

W Dick

Publications and source records attributed to W Dick.

At least 163 records · Page 9Linked to original sources
PubMed1988

Comparable evaluation of orally active beta-lactam compounds in ampicillin-resistant gram-positive and gram-negative rods: role of beta-lactamases on resistance.

The antibacterial activity of the recently developed cephems cefixime and cefetamet-pivoxyl was evaluated in 408 gram-positive and gram-negative rods, all isolated recently from clinical specimens, and compared to that of other orally active agents such as ampicillin, amoxycillin + clavulanic acid, cefaclor, cefuroxime-axetil and to ceftriaxone. With regard to ampicillin-resistant Enterobacteriaceae ceftriaxone proved to be the most active agent, followed by cefixime and cefetamet, whereas cefuroxime was less active. Cefaclor and amoxycillin + claculanic acid were active against ampicillin-resistant Escherichia coli, Klebsiella pneumoniae, and Proteus ssp. isolates. All beta-lactam compounds exhibited poor activity against Acinetobacter anitratus isolates, but were highly active against Haemophilus influenzae with the exception of cefaclor. Both cefixime and cefetamet were poorly active against Staphylococcus aureus, but highly active against beta-hemolytic streptococci. Moreover, both compounds remained unaffected by the production of plasmid-mediated beta-lactamases such as the TEM or OXA enzymes. Resistance to both agents was observed in Enterobacteriaceae that produced large amounts of chromosomally mediated enzymes; their affinity to the class I enzyme from Enterobacter cloacae was somewhat lower than that of other third-generation cephalosporins. However, in contrast with these agents breakdown of cefixime and cefetamet by a class IIIa enzyme form Proteus vulgaris was marginal. In methicillin-resistant S. aureus isolates there was a complete cross-resistance between all beta-lactam compounds included in this study.

Ampicillin Resistance↗
PubMed1988

[Acute management of spinal injuries. The thoracic and lumbar spine, surgical therapy].

The aims of internal fixation of thoracic and lumbar spinal fractures are immediate stability, preservation of spine mobility, and restoration of the anatomical form of the vertebra and of the canal diameter at acceptable risks. All these aims together can be achieved only by short posterior pedicle fixation systems, such as the external spine fixator, the various internal spine fixators, special dorsal Roy-Camille plates, Wolter plates, and the combined anterior and posterior unisegmental fusion with the USIS system. Isolated anterior procedures necessitate additional bracing. The indications for operative treatment are discussed in the light of the above-mentioned methods.

Bone Plates↗
PubMed1988

[Efficacy and safety of the benzodiazepine antagonist RO 15-1788].

In a randomized, prospective, double-blind trial we investigated the efficacy and safety of the benzodiazepine antagonist RO 15-1788 in 57 patients undergoing general surgery. Anesthesia was induced and maintained by a combination of Flunitrazepam-Fentanyl-Pancuronium. Inhalation anesthetics were excluded from the study. After reversal of any residual relaxant effect we titrated RO 15-1788 or placebo by repeated i.v. administration of 0.1 mg (= 1.0 ml) up to a maximum dosage of 1.0 mg or to a definite arousal reaction. Before as well as 5, 10, 15, 30, 60, and 120 min after injection of the trial substance we evaluated efficacy (sedation, comprehension and collaboration, orientation in time and space), presence of anterograde amnesia, side-effects, hemodynamics, and subjective patient assessment by a point scale. RO 15-1788 significantly improved the level of consciousness (P less than 0.005) at a dosage of 0.59 +/- 0.29 mg at 5, 15, 30, and 60 min after administration as well as orientation in time and space (P less than 0.005) after 30 min. There was significantly less anterograde amnesia (P less than 0.005) after 15, 30, and 60 min. Symptoms of a benzodiazepine rebound effect after 120 min indicate a short half-life time of RO 15-1788. We did not observe any hemodynamic side effects. Local tolerance was good. Side effects in terms of nausea (1 case), vomiting (4), euphoria or dysphoria (2), benign cardiac arrhythmias (1) or a state of excitation (1) occurred several times after RO 15-1788 as well as after placebo (nausea 2, vomiting 6, muscular tremor 1). Our results indicate the efficacy and safety of RO 15-1788.

Adult↗
PubMed1988

[In vivo detection of the Christiansen-Douglas-Haldane effect in clinical conditions].

The Christiansen-Douglas-Haldane effect, also termed Haldane effect, describes the dependence of CO2 absorption by blood on the degree of hemoglobin oxygenation. Under the physiological condition of an "open" system between blood and alveolus, the arterial partial pressure of CO2 (paCO2; mmHg) must range below the mixed-venous (pvCO2; mmHg) value. During the nonphysiological situation of a "closed" system, e.g. hyperoxic apnea after adequate pre-oxygenation (O2 uptake with lack of CO2 delivery), paCO2 can assimilate to pvCO2 and even exceed it. The remainder has often been termed a "paradoxical phenomenon". It was the aim of this study to prove the Haldane effect in vivo in the "closed" system of hyperoxic apnea. Eighty patients (ASA II-IV, NYHA II-III) scheduled for coronary surgery gave written informed consent and were examined. Following the preparations for induction (venous and arterial cannulas, pulmonary artery catheter), they were pre-oxygenated with 6 l O2/min until induction of anesthesia was achieved. Pre-oxygenation was maintained actively/passively until intubation. At the onset and the end of intubation the arterial (a) and mixed-venous (v) blood gas status (pHa, pHv, saO2 and svO2 (%), paO2 and pvO2, paCO2 and pvCO2 were determined using the Corning 170 pH/blood gas analyzer and the Corning 2500 CO-oximeter. Statistical analysis of the data was based on Student's t-test for paired samples. Periods of apnoea ranged between 60 and 180 s. The data were allocated to three groups, depending on the duration of apnea: Group I: 60-100 s; Group II: 101-140 s; Group III: 141-180 s.(ABSTRACT TRUNCATED AT 250 WORDS)

Apnea↗
PubMed1988

[The effect of atropine, fentanyl and alfentanyl on cardiocirculatory parameters and thoracic rigidity in the induction phase of intubation anesthesia].

Fentanyl and alfentanil may cause bradycardia if used in combination with succinylcholine during induction of anaesthesia. We therefore studied the influence of atropine, fentanyl and alfentanil on the haemodynamics of 90 urological patients (ASA I, II), who were allocated at random to six groups containing 15 patients each. Induction of anaesthesia was carried out using atropine 0.01 mg/kg-1, fentanyl 0.15 mg or alfentanil 1.5 mg depending on the assigned group: I atropine + fentanyl, II: atropine + alfentanil, III: fentanyl, IV: alfentanil, V: control (no atropine, no analgetic), VI: atropine. Following 2 mg alcuronium and thiopentone 4 mg/kg-1 intubation was performed with 2 mg/kg-1 succinylcholine. Atropine in combination with fentanyl caused a significant increase in heart rate following endotracheal intubation (p less than 0.05). Arrhythmias occurred in the groups with atropine in 4 out of 45 cases, while a chest wall rigidity was not influenced by atropine. Bradycardia occurred after fentanyl or alfentanil with atropine in the same frequency as without atropine. According to our results the routine use of atropine for induction of anaesthesia with thiopentone/fentanyl or alfentanil even in combination with succinylcholine is not required in ASA I or II patients.

Adult↗
PubMed1988

[Undesirable effects following the local injection of ornipressin during general anesthesia: can the risk be lessened? A prospective study].

Complications associated with local infiltration of ornithine-8-vasopressin (O-8-V) during general anesthesia (GA) are documented. Severe and extremely severe complications range around 20%; fatalities have been reported. The incidence of complications is associated with age, pre-existing cardiovascular or pulmorespiratory disease, and dosage administered. In a prospective study, we investigated 169 patients following a standardized protocol. Maximum dosage was 2 IU, diluted to 0.25 IU/ml in 0.9% saline. Patients with cardiovascular or respiratory disease and those below 1 or above 50 years of age were excluded. GA consisted of tracheal intubation and controlled ventilation with enflurane in N2O/O2 and intravenous fentanyl. Cardiovascular monitoring was by ECG with arrhythmia detection, plethysmography, and oscillometric - in some patients intraarterial - blood pressure measurement. Ventilatory monitoring included respiratory rate, tidal volume, inspiratory and expiratory O2 concentrations, capnometry, and end-tidal enflurane concentration. Local infiltration of the oral soft tissues with O-8-V was performed after a steady-state of anesthesia was achieved and 20 min before commencement of surgery. No severe or extremely severe complications or arrhythmias were observed. A moderate increase in blood pressure was seen in 43% of patients; in 10% this increase was 30-70 mmHg (systolic and/or diastolic). For data analysis, patients were allocated to 4 groups according to the dosage of O-8-V administered. Systolic and diastolic pressures increased to above control in all groups; however, no inter-group differences were found for blood pressure or heart rate. It is concluded that the risks associated with local infiltration of soft tissues with O-8-V during GA can be attenuated by a protocol such as the one established for this prospective study.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Topical↗
PubMed1988

[Value of preoperative screening studies].

In order to develop a sensitive and economically reasonable preoperative screening program capable of identifying perioperative risk factors, we performed a prospective study on patients scheduled for elective urological surgery. According to age, 379 patients were assigned to six groups. After the history and physical examination had been completed the attending anesthesiologist classified the patient's anesthetic risk according to ASA criteria. Furthermore, based on his clinical impression he ordered an individual set of screening parameters (laboratory tests, X-ray films, electrocardiography (ECG), and other appropriate diagnostic procedures) to be done. This "individual" screening and its results were compared with the results of the larger "routine" preoperative screening program performed independently of the study for all patients. All cases were then followed up in order to document perioperative complications. We were thus, able to recognize risk-identifying screening parameters resp. pathological findings missed by the "individual" screening. Laboratory tests from the nonselective "routine" screening yielded pathological results in a relatively high percentage of 31.4% of cases. ECG alterations or chest X-ray findings relevant to the patient's anesthetic management were present in 26.1% resp. 13.6%. Observations missed by the "individual" screening, though important for the prevention of perioperative complications, were pathological ECGs in only 1.9% of all cases. An influence of patient age on the frequency of pathological screening results and perioperative complications could be shown. Laboratory tests, chest X-rays and additional diagnostic procedures should be restricted to patients with pathological results or physiological examination. Our results underline once more the importance of a carefully taken history, a meticulous physical examination and the preoperative performance of an ECG for patients of every age scheduled for anesthesia and surgery.

Adolescent↗
PubMed1988

[Assessment of technology in intensive care medicine].

In recent years intensive care medicine has been accused of becoming a purely technological medicine. Those of this opinion, however, fail to realize that automatic ECG and blood pressure monitoring have improved the safety and validity of vital parameters and have relieved qualified personnel from unnecessary tasks. The controversial discussion of invasive monitoring, particularly the use of pulmonary artery catheters, led to new and improved technology. Infusion technology and artificial ventilation are characteristic examples which demonstrate the essential need for technology in intensive care medicine. The same is true for extracorporeal CO2 elimination, pacemaker technology, haemofiltration, etc. Computer technology will lead to further improvement in safety and patient care, protecting the patient from human and technical errors.

Critical Care↗
PubMed1988

[Effect of different pre-oxygenation procedures on arterial oxygen status].

There are different opinions regarding efficiency, duration, and techniques of preoxygenation. It was the aim of our study to systematically investigate the effectiveness of different preoxygenation methods by means of arterial blood gas parameters (paO2, SaO2, and CaO2). METHODS. After receiving informed consent, 80 patients undergoing coronary bypass grafting (NY-HA II-III, ASA III-IV, mean age 57 years) were randomized in eight groups, each with a different preoxygenation technique (Table 1). During normocapnic preoxygenation (Table 2), the following parameters were compared: duration of preoxygenation (3 vs. 5 min), manner of holding the face mask (tightly fitting vs. one digit away from mouth and nose), and oxygen flow (6 vs. 10 l/min) via anesthesia circuit system. Arterial blood gases were analyzed with a Corning 170 pH/blood gas analyzer and a Corning 2500 CO-oximeter. For statistical analysis Student's t-test was used. P less than or equal to 0.01 was considered to be significant (*). RESULTS. As Fig. 1 shows, the different preoxygenation techniques affected paO2 values differently: oxygen flow had a greater influence than duration of preoxygenation. Most important was the manner of holding the face mask. With a tightly fitting mask, preoxygenation was more effective than with the face mask one digit away from mouth and nose, independent of preoxygenation time and oxygen flow (Table 3). The SaO2 (Fig. 2) increased in the same manner with the different preoxygenation techniques from 94.0% to 97.5% (Table 3); CaO2 (Fig. 3) was influenced in a similar way (16.7 ml/dl to 17.4 ml/dl).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Gas Analysis↗
PubMed1988

[Quality of buprenorphine and morphine as components of combined anesthesia].

Perioperative effects of buprenorphine during and after combined anesthesia for gynecological laparotomies were compared to those of morphine. In a controlled, randomized study two similar groups of patients received flunitrazepam (0.016 mg/kg) and either buprenorphine (0.008 mg/kg) or morphine (0.333 mg/kg); all patients were ventilated with a N2O/O2-mixture. To maintain adequate anesthesia, additional injections of buprenorphine or morphine and a volatile anesthetic agent (enflurane, less than 1.0 vol.%) were administered as needed. In some patients in both groups the injection of thiopental (1-2 mg/kg) became necessary for induction of anesthesia. Hemodynamic parameters showed a slight but not significant increase during intubation and remained stable intraoperatively (Figs. 1 and 2). The frequencies of additional intraoperative injections of buprenorphine or morphine and modalities of enflurane administration were similar in both groups. Based on an awakeness score, recovery from anesthesia was similar in both groups (Fig. 3). All patients were pain-free for a long period postoperatively (pain score 1-2, duration 6-10 h) (Fig. 4). In both groups respiratory depression could be demonstrated by means of ventilatory CO2 response (Figs. 6 and 7). The respiratory depression was of no clinical importance and seems to have been due to the combination of a long-acting benzodiazepine with an opiate. There were no differences in the occurrence of nausea and vomiting in both groups. Buprenorphine seems to be an alternative to morphine in combined anesthesia.

Acid-Base Equilibrium↗
PubMed1988

[Models and methods in animal experiments in resuscitation].

Various animals models and several different methods are used in cardiopulmonary resuscitation (CPR) research. The animals used most frequently are dogs and pigs, but in each species thorax configurations, which might be an important factor in the mechanism of blood flow during CPR, are at great variance. The influence of anesthetics on cardiopulmonary and cerebral functions during and following resuscitation are largely unknown, and accordingly there is great variance in the techniques employed by individual researchers. The experimental design chosen with regard to the effect of heparin and epinephrine, induction, form, and duration of cardiac arrest as well as duration of CPR is often very different; comparisons are therefore difficult to make. During CPR ventilation is monitored using ventilatory pressure, frequency, tidal volume, and arterial blood gases. Thorax compressions are characterized by frequency, direction (sagittal, transversal), technique (mechanical, manual), relationship of time between compression and relaxation (50:50, 40:60), and depth of compression (power used, esophageal pressure, arterial blood pressure). Effects of CPR techniques are demonstrated during CPR by cardiovascular parameters. In addition to recording of blood pressure and blood flow, examination of regional perfusion rates using radioactive microsphere techniques is common. 24-h surveillance and extensive neurological tests are carried out during recovery following CPR.

Anesthesia↗
PubMed1988

[Changes in temporomandibular joint functions in various general anesthesia procedures].

In a clinical study conducted in 1986 on 100 patients, we were able to demonstrate that intubation leads to the occurrence of temporary disturbances of the stomatognathic system. To verify these results, a double-blind study was conducted involving 140 patients of ASA groups I and II. Further acceptance criteria were: operation outside of the head and neck area, no throat pack or gastric tube, and the requirement of dental antagonists on the left and right side. Group composition: Group A: oral intubation with a laryngoscope (n = 50); Group B: nasal intubation using a fiberoptic endoscope (n = 40); Group C: face mask (n = 50) Groups A and B were divided at random. Balanced anesthesia was performed for all patients. In group B, after nasal intubation the mandible was placed and fixed in the habitual occlusion position. The patients had a dental examination preoperatively and on 1st, 2nd and 3rd postoperative day. Parallel to this study, we also interviewed 400 patients after routine intubation anesthesia with regard to postoperative temporomandibular joint (TMJ) symptoms. Groups A, B, and C were comparable in age, sex, height, weight, preoperative values of maximal mandibular movement, and pathological findings of the TMJ (Tables 1-3); the only differences were a longer mean duration of surgery in groups A and B than in group C (P greater than 0.05) and that women described more stomatognathic disorders in the preoperative medical history than men.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[Biomedical and clinimetric approaches in determining the causes of perioperative risk: developing a German ASA classification].

Perioperative risk research with biomedical (biochemical, physiological) methods must grow up as a main topic in surgical research. However, operative risk has also to be analysed with methods of clinimetrics, such as formal (objective) decision making and epidemiology. Only by this way a convincing practical dimension is added to basic scientific statements. ASA-classification of the preoperative physical status is a global index for estimating the operative risk. It contains objective findings, subjective impressions and the final clinical judgement. For this reason it is so flexible. For a multicentre trial on perioperative risk and histamine an empirical index was constructed using both the ASA-classification and the Mannheim-Munich risk check list.

Germany, West↗
PubMed1987

[Perioperative risk--controversies on pathogenesis--integration of various aspects].

1) The summary done for perioperative risk factors should be jointly calculated by surgeons and anaesthetists. 2) Risk classification has to be accepted by both partners. 3) Preoperative screening has to be checked for relevance. 4) Known risk factors have to be eliminated by adequate pretreatment. 5) The operative procedure, anaesthesia and monitoring should be planned well ahead in risk patients. 6) Postoperative monitoring and postoperative treatment should be subject to joint discussions.

Anesthesia, General↗
PubMed1987

Selection and properties of Pseudomonas aeruginosa variants resistant to beta-lactam antibiotics.

The relation between basal and inducible beta-lactamase production and resistance to beta-lactam compounds was studied in five clinical Pseudomonas aeruginosa isolates and their corresponding resistant variants selected in the presence of either piperacillin, ceftazidime or aztreonam. In all wild-type strains enzyme levels were barely detectable in the uninduced state and most beta-lactams, including sulbactam and clavulanic acid, exhibited poor induction potency. Imipenem proved to be the most potent inducer in both these strains and their resistant variants. In the variants selected by either piperacillin or ceftazidime enzyme production amounted to 1.28 units/mg protein of the cell-free supernatants following the addition of beta-lactams as inducers. Additionally, these variants exhibited the phenomenon of "non-specific" induction, i.e. the increase of enzyme production by either a complex nutrient medium or by addition of vitamins. Enzyme production in the aztreonam-resistant variants was identical to that in the wild-type strains with a single exception, where the entire derepression of beta-lactamase production in one of the variants took place. Derepression of the chromosomally mediated enzyme affects the susceptibility to ureidopenicillins more than that to carboxy-penicillins and cephalosporins, whereas the beta-lactamase-independent resistance results in increased resistance to all beta-lactams with the single exception of imipenem.

Anti-Bacterial Agents↗