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Biomedical subjects

M Tryba

Publications and source records attributed to M Tryba.

At least 73 records · Page 4Linked to original sources

Conservative treatment of stress ulcer bleeding: a new approach.

Stress ulcer prophylaxis diminishes but does not eliminate the risk of severe bleeding from this complication. In 70-80% of the cases the source of bleeding is hemorrhagic gastritis. No controlled studies exist which have in particular investigated conservative therapy in patients with stress-induced hemorrhage. Even effective measures to suppress gastric acid secretion or to reduce splanchnic blood flow are ineffective in 10-40% of intensive care unit patients with stress-induced bleeding. In these cases total gastrectomy has so far often been the only therapeutic approach. We report our experience with a new approach in treating severe stress-induced hemorrhagic gastritis after ineffective primary treatment with H2-receptor antagonists, pirenzepine and somatostatin. Continuous gastric lavage with 5-10 l ice-cold Ringer's solution was used until complete cessation of bleeding, as evident from clear lavage. Repeated administration of 12 g sucralfate (60 ml) at 2-h intervals for 24 h through a gastric tube was used to prevent recurrence of bleeding and to promote healing. Sucralfate was reduced on the 2nd and 3rd day to 20 ml 2-hourly and later to 10 ml 4-hourly. In four patients this treatment was used as an ultima ratio when the patients were already scheduled for total gastrectomy. A total of 23 patients were treated during a 7-year period; all of them responded successfully, and no patient required surgery.

Adult↗

The gastropulmonary route of infection--fact or fiction?

Published studies relating to whether medicinal stress-bleeding prophylaxis leading to an increase of gastric pH favors the development of bronchopulmonary infections are reviewed. Results from studies in healthy humans, patients with ulcer disease, and patients in the intensive care unit (ICU) clearly show that the risk of gastric bacterial colonization significantly increases relative to increasing gastric pH. Moreover, a drug-induced increase of gastric pH leads directly to gastric bacterial colonization also in patients in the ICU, above all with bacteria typical of the gastrointestinal tract. Comparing the different bacterial spectra of the oropharynx, stomach, and upper small intestine, it becomes clear that the stomach is a reservoir of bacteria independent of the oropharynx and also subject to retrograde colonization due to the duodenogastric reflux. Both by means of microbiological and in particular direct detection procedures, it can be demonstrated that in at least 30-40% of intubated patients a gastropulmonary route of colonization occurs. In patient groups without a medication-induced increase of gastric pH the number of bacteria detected in the tracheal secretion is about 33% less than in the case of conventional stress-bleeding prophylaxis. These findings make it understandable that a highly significant increase in the pneumonia rate is seen in patients receiving pH-increasing stress-bleeding prophylaxis versus control groups without therapy essentially influencing gastric pH. A risk score was developed that allows an easy description of those patients who are at an increased risk of pulmonary infections due to the gastropulmonary route of colonization.

Anti-Ulcer Agents↗

[What benefit and harm can be expected from screening and routine examinations and from their omission?].

Benefit and harm of screening and routine tests or their omission are dealt with in four parts. In the first part methods are described to evaluate the diagnostic value of medical testing. The concepts of diagnostic sensitivity, diagnostic specificity, and pre- and posttest probability of a diagnosis are defined. It is then shown how these concepts intercorrelate and how their numerical values can be calculated ("Bayes" theorem"). In consideration of the above mentioned intercorrelations, the second and third parts deal with the diagnostic value of preoperative routine tests from an anaesthesiological viewpoint, and the diagnostic value of other screening and follow-up tests is discussed from a gynaecological point of view. Pre-operative laboratory tests are necessary, and necessary only then, if careful evaluation of patient history and physical examination reveal pathological findings or risk factors. The benefits from regular lab-screening tests and follow-up tests, as recommended to the gynaecologists, are low. This is due to the large share of "healthy" women among the gynaecological patients, as well as the fact that treatment of early detected recurrences shows no demonstrable advantage over treatment of later detected recurrences. In the fourth part, we show that no adverse forensic consequences are to be expected if diagnostic tests are omitted because of demonstrably low diagnostic value. In case of legal procedures against the physician, a medical expert will have to evaluate the diagnostic value of the omitted test objectively from an "ex-ante" point of view, using the methods defined in the first part.(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnosis, Differential↗

Sucralfate versus antacids or H2-antagonists for stress ulcer prophylaxis: a meta-analysis on efficacy and pneumonia rate.

OBJECTIVES AND METHODS: Histamine2 (H2)-receptor antagonists and antacids have been the basic drugs for the prevention of stress bleeding in ICU patients during the past decade. Recently, drugs without major influence on gastric pH have been investigated in stress bleeding prophylaxis. Therefore, a meta-analysis (Mantel-Haenszel test) was undertaken to determine the efficacy of sucralfate in the prevention of macroscopically visible stress bleeding, as well as the influence of sucralfate on the frequency of pulmonary infections. RESULTS: The efficacy of sucralfate was compared with H2-antagonists in nine studies and with antacids in eight studies. Sucralfate was significantly more effective than H2-antagonists (typical odds ratio 0.532, 95% confidence interval 0.303 to 0.933) and equally as effective as antacids (typical odds ratio 0.868, 95% confidence interval 0.452 to 1.667). The pneumonia rates of those patients who were administered sucralfate were compared with the rates of those patients who were given H2-antagonists in five studies and with those patients who were given antacids in four studies. Pneumonia was a significantly more frequent occurrence under prophylaxis with H2-antagonists (typical odds ratio 0.498, 95% confidence interval 0.316 to 0.783) as well as with antacids (typical odds ratio 0.402, 95% confidence interval 0.235 to 0.687). CONCLUSION: Sucralfate is an effective drug for the prevention of stress bleeding that minimizes the risk of nosocomial pneumonia in long-term ventilated ICU patients.

Antacids↗

[Histamine release and cardiovascular reactions to implantation of bone cement during total hip replacement].

Cardiovascular reactions to acrylic bone cement in patients with total hip replacement are a common complication. Hypotension and arrhythmias are the most frequently observed symptoms. Elderly patients with fractures of the femoral neck constitute a special risk group. In some patients these reactions can be fatal. The mechanisms suggested to explain these reactions are embolism of air, polymer or fat, reaction to the heat, and toxic or vasodilating effects of the acrylic monomer. In a pilot study and in a case report a significant rise of the plasma histamine was described following cementation of the femur. We therefore performed an investigation to find whether application of bone cement to the femur caused histamine release in elective hip surgery, and, independently of this, also investigated whether premedication with H1- + H2-antagonists had any effect on the cardiovascular reactions due to bone cement implantation into the femoral shaft in elderly patients with hip fracture. METHODS. Part I. In all, 40 patients, scheduled for elective surgical hip replacement were anesthetized by general or epidural anesthesia. Patients were continuously monitored by ECG. Blood pressure was recorded noninvasively at 2-min intervals during the study. Blood samples for the determination of the plasma histamine were taken immediately before implantation of the bone cement into the femur, and 2, 5, and 10 min after. Part II. A further group of 20 patients aged greater than or equal to 70 years with fractures of the femoral neck and in whom total hip replacement was planned were included in the study. In this group, 10 patients were randomly assigned to receive 4 mg clemastine + 400 mg cimetidine i.v. about 15 min before implantation of the bone cement. All patients were operated on under general anesthesia. ECG was monitored continuously and blood pressure was monitored at 2-min intervals during the study. Changes of the blood pressure and heart rate and therapeutic interventions following the implantation of the bone cement were documented. RESULTS. Part I. In 11 of the 40 patients (27.5%) plasma histamine increased by greater than 0.5 ng/ml (9 patients greater than 1 ng/ml). In comparable groups (patients with a control systolic blood pressure less than or equal to 130 mmHg) the histamine responders showed a significantly greater reduction in systolic blood pressure (-5.7 +/- 14.7 vs -17.7 +/- 8.6 mmHg). Part II. In the control group we observed a significantly greater fall in systolic blood pressure than in premedicated patients (41.5 +/- 25.4 vs 11.0 +/- 13.4 mmHg). In the control group 7 of the 10 patients required therapeutic interventions, while in the premedicated group only one therapeutic intervention was necessary (P less than 0.05). DISCUSSION. We have demonstrated that the implantation of acrylic bone cement into the femur may increase plasma histamine by greater than 1 ng/ml. In elderly patients with preexisting cardiac diseases or/and hypovolemia even moderate histamine release can cause serious, sometimes potentially fatal, cardiovascular complications. In this special risk group with hip fractures we found a significant reduction in the frequency of cardiovascular reactions to bone cement implantation in patients premedicated with H1 + H2 antagonists. Because we also observed significant falls in systolic blood pressure in premedicated patients, we assume that the pathogenesis of cardiovascular reactions to bone cement implantation is multifactorial. It may be that potentially lethal complications only occur if two or more of the predisposing factors (hypovolemia, myocardial insufficiency, arrhythmia, embolism, histamine release) are present simultaneously. Pre- and intraoperative measures therefore have to be instituted to eliminate all possible risk factors.

Aged↗

[Rational prevention of stress hemorrhage--effectiveness, side effects, costs].

Stress ulcer bleeding occurs in special risk groups. The main cause of this complication is the loss of protective mechanisms of the gastric mucosa. Preventive measures aim to strengthen the protective mechanisms or to lower the aggressive factors, mainly the gastric acid. Meta-analysis demonstrates that drugs that enhance the protective mechanisms are superior to a regimen that only reduces the secretion of gastric acid. The most important side effects of stress ulcer prophylaxis are related to the inhibition of gastric acid, the blockade of the cytochrome P450 system and the blockade of central and cardiac H2 receptors. Handling difficulties most often occur during treatment with antacids. The costs of prophylaxis are lowest for sucralfate. Rational decision analysis shows that pirenzepine given as parenteral medication and sucralfate as enteral medication are the most suitable drugs for stress ulcer prophylaxis.

Anti-Ulcer Agents↗

Prophylaxis of stress ulcer bleeding. A meta-analysis.

Recent studies have reported upper gastrointestinal tract bleeding in 5-25% of intensive care unit (ICU) patients with severe stress despite the use of antacids and/or H2-antagonists. To evaluate the efficacy of this regimen, a meta-analysis of all prospective studies on the prevention of stress bleeding, available from the international literature, was conducted. Only macroscopically visible bleeds were considered. Because alkalinization of the gastric juice has been incriminated in facilitating gastric and pulmonary colonization, agents with little or no influence on the gastric pH have been increasingly investigated in stress bleeding prophylaxis. The meta-analysis was therefore extended to determine the efficacy of two newer substances, pirenzepine and sucralfate, in preventing macroscopically visible stress bleeding, as well as their influence on pulmonary infections and mortality. Antacids and H2-antagonists proved to be significantly superior to untreated controls, with the tendency in favor of antacids administered in short intervals as compared to H2-antagonists. Pirenzepine and sucralfate were significantly superior to H2-antagonists, and sucralfate was as effective as an adequate antacid regimen. Patient groups treated with antacids or H2-antagonists showed a significantly higher risk for the development of nosocomial pneumonia. The most significant differences was found in long-term ventilated patients compared with patients treated with sucralfate. In the same patient group, antacids and H2-antagonists also showed a significantly higher mortality rate than sucralfate.

Critical Care↗

Stress bleeding prophylaxis with sucralfate. Pathophysiologic basis and clinical use.

The development of acute stress bleeding in intensive-care patients occurs on a multifactorial basis. The basic mechanism lies in the imbalance between aggressive and protective factors. Most intensive care patients show a reduced acid secretion, a reduction of the gastric mucosal blood flow, and a decreased mucus and bicarbonate secretion. Sucralfate enhances most of the defensive mechanisms. These actions are the pathophysiologic basis of the efficacy of sucralfate in the prevention of stress bleeding. Because sucralfate has only a minor influence on the gastric pH and at the same time has proven bactericidal effects, gastric and gut bacterial overgrowth is significantly reduced. These effects explain the observed differences in mortality between sucralfate and alkalinizing drugs like antacids or H2-antagonists. The indications and limits of sucralfate in stress bleeding prophylaxis are pointed out.

Clinical Trials as Topic↗

Side effects of stress bleeding prophylaxis.

Conventional stress bleeding prophylaxis with antacids or histamine (H2)-antagonists, as well as the newer mucosa-protective drugs pirenzepine and sucralfate, are satisfying most of the clinicians with regard to efficacy of stress bleeding prevention. Therefore, potential side effects are attaining crucial importance with regard to the drugs to be used. Pharmacologic blockade of cardiac H2-receptors increases the risk of bradycardia and negative inotropic effects as well as coronary vasoconstriction at least in the presence of elevated plasma histamine levels. Intracardiac injection of pirenzepine can lead to temporary tachycardia. Elderly patients have been shown to be at an increased risk of side effects to the central nervous system when treated with H2-antagonists. These drugs can also induce toxic effects in the liver. Cimetidine leads to interactions with a number of drugs used in the intensive care unit. In patients with pre-existing pulmonary diseases, H2-antagonists have been demonstrated to increase pulmonary bronchoconstriction. Alkalinization of the gastric juice is associated with a significant increase in colonization of gram-negative bacteria in the stomach. In intubated patients, aspiration of stomach contents occurs in 30 to 40 percent of the patients. A number of studies have shown a direct correlation between alkalinization of the gastric juice and pulmonary infections. Sucralfate and to a lesser degree pirenzepine can reduce the risk of pulmonary infections. Sucralfate also exerts a bactericidal effect. Recent investigations support the hypothesis that alkalinization of the stomach also increases the risk of systemic infections. This may be the main reason for the observation that at least in ventilated patients sucralfate, unlike H2-antagonists or antacids, leads to a significant reduction of the mortality rate compared with conventional stress bleeding prophylaxis.

Bacteria↗

[Retard morphine in the long-term therapy of severe tumor pain].

35 patients with severe cancer pain received oral retard morphine. Pain reduction was achieved in each case; duration of effectiveness was between 8 and 12 hours. Mean daily dose was 230 mg morphine, but in individual cases the maximal daily dose had to be over 800 mg. The Karnofsky index of physical capacity was increased in all patients. The main side effect was constipation, which actually increased in the course of treatment. On the other hand, nausea and vomiting decreased after a few weeks. No dependence developed in any of the patients. This form of morphine medication thus was effective over long periods and it has become an important part in the range of strongly effective analgesics.

Adult↗