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Biomedical subjects

H Metzler

Publications and source records attributed to H Metzler.

At least 55 records · Page 3Linked to original sources

[Education of the medical student in first aid, emergency and disaster medicine--the Graz model].

In Austria emergency and disaster medicine is a young interdisciplinary subject. It is only a borderline discipline encompassing different medical subjects and was subdivided into emergency medicine for medical doctors only and first-aid for lay people and emergency technicians. In fact, since emergency medicine without first-aid can't be successful, the Department of Anaesthesiology at the University of Graz let all students of the medical faculty have a comprehensive education in the treatment of injured of acutely ill patients. According to the three steps of the study lectures and practices, all parts of first-aid, emergency and disaster medicine were offered. In spite of the short time since this has been running, we found a good acceptance and we hope to increase the interest evinced by medical students in our training programme.

Austria↗

[Total cavo-pulmonary connection as a therapeutic principle in anatomical and functional univentricular heart].

The original Fontan operation was employed for patients with tricuspid atresia, but its application has been extended to a broad spectrum of congenital cardiac defects with a functional or anatomical single ventricle. From 1989 to 1995, 35 patients (23 males, 12 females) underwent a modified Fontan procedure; their age ranged from 14 months to 15 years (mean 5.1 a). Indications for operation were the following: D(S)ILV = 16, TA = 9, MA = 3, TGA with straddling AV-valve = 2, DORV = 4 and criss-cross heart = 1. The same surgical technique was utilized in all patients with redirection of the systemic venous return by means of a bidirectional cavopulmonary anastomosis and an intraatrial baffle, adaptable to all the various forms of underlying anatomy. Associated anomalies such as dextrocardia, coarctation, anomalous systemic or pulmonary venous return, subaortic stenosis and situs anomalies were present in 26%, 9%, 26%, 9%, and 20%, respectively. 12 patients were presumed to be at high risk and underwent a two-stage procedure (n = 7 bidirectional Glenn preceding the definitive repair and n = 5 a fenestration of the intraatrial baffle). Risk factors in our group of patients were: age under 2 years, abnormal systemic venous drainage, stenotic pulmonary arteries, PVR over 2 Wood units, mPAP over 15 mmHg, AV-valve incompetence, subaortic obstruction and ventricular dysfunction. Two patients had failure of the total cavo-pulmonary connection necessitating the take-down to a bidirectional Glenn anastomosis in the early postoperative period, with one death. Hospital mortality was 24% (n = 8). One child did not survive complications following the fenestration closure 4 months postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Prolonged extracorporeal organ support in a 2-year-old boy after cardiac surgery.

A case report of a 2-year-old boy who developed severe post-operative low cardiac output, sudden cardiac arrest and consecutive multiple organ system failure after open heart surgery is described. Initially the hemodynamic situation was stabilized by extracorporeal membrane oxygenation (ECMO) combined with continuous hemofiltration (CHF) carried out for 7 days. Continuous veno-venous hemofiltration (CVVH) was necessary for further 17 days. One episode of plasmapheresis restored transiently a severe post-operative coagulopathy and enabled the removal of the pulmonary artery catheter and the chest tubes.

Cardiac Output, Low↗

Troponin T as a marker of perioperative myocardial cell damage.

Unstable angina in patients undergoing CABG surgery is associated with a higher morbidity and mortality compared to patients with stable angina. Mortality ranges between 2 and 10% (20, 21). The importance of the preoperative status is only clear and well documented for patients with unstable angina who are unresponsive to medical treatment, patients who undergo emergency revascularization, and for patients with failed angioplasty. The adverse outcome in elective patients with unstable angina was statistically not significantly different from those with stable angina. Therefore, we may assume that in stabilized patients with unstable angina and minor myocardial cell damage intraoperative determinants like the duration of the aortic clamping period or the degree of revascularization are more relevant than the preoperative ones. These determinants may also be reflected by a marked and significant increase of troponin T in both groups during and after surgery. As for other cardiac enzymes, this increase of troponin T beginning immediately after reperfusion of the cardioplegic heart may limit its diagnostic value after cardiac surgery (6,22). On the other hand, troponin T may serve as a marker in assessing the effectiveness of different cardioprotective measures. Nevertheless, preoperatively elevated troponin T levels may indicate a jeopardized myocardium with an ongoing process of myocardial cell damage and may be of prognostic value. Antianginal and antiischemic therapy, therefore, has to be continued and completed until the day of surgery in these high-risk patients.

Angina, Unstable↗

Preoperative myocardial cell damage in patients with unstable angina undergoing coronary artery bypass graft surgery.

BACKGROUND: Troponin-T is one of the contractile proteins of the myocardium. Its release into the circulation indicates various degrees of myocardial cell damage. Troponin-T may be measured in serum with a recently developed enzyme immunoassay. This immunoassay was used to evaluate the preoperative myocardial cell damage in patients with stable and unstable angina undergoing elective coronary artery bypass graft surgery, and it was compared with conventional assays of creatine kinase (CK) MB isoenzyme activity and mass. METHODS: Twenty-one patients with unstable angina and 31 with stable angina were studied. Troponin-T, CK-MB activity, and CK-MB mass were measured 24 h before anesthesia and surgery, immediately before induction of anesthesia, before and after cardiopulmonary bypass, at the end of surgery, and 24 h afterward. RESULTS: In 90% (19 of 21) of the patients with unstable angina, troponin-T was increased 24 h before anesthesia (median 0.33 microgram/l, range 0.15-5.2 micrograms/l), whereas only 3% (1 of 31) of the patients with stable angina had increased values (median 0.0 microgram/l, range 0.0-0.53 microgram/l). The difference was statistically significant (P < 0.001). The same profile was found in patients with and without unstable angina immediately before induction of anesthesia (86% [18 of 21] and 0%, respectively) and before cardiopulmonary bypass (62% [13 of 21] and 0%, respectively). In contrast to troponin-T, CK-MB activity was increased in only 0-14% of patients with unstable angina, and CK-MB mass was increased in only 9-24%. After bypass troponin-T increased in both groups (P < 0.01), but there was no longer a statistically significant difference between the groups. Twelve percent (4 of 31) of the patients in the stable angina group and 28% (6 of 21) in the unstable group had major cardiac events (P not significant). CONCLUSIONS: The study data suggest that many patients with unstable angina undergoing elective coronary artery bypass graft surgery have already increased troponin-T levels preoperatively, although conventional biochemical markers such as CK-MB activity and mass are at a normal range. Increased troponin-T and normal CK-MB concentrations may reflect some degree of ischemic myocardial cell damage. Because of the small number of patients in the study, the influence of preoperative myocardial injury on perioperative outcome could not be clarified.

Adult↗

Subcutaneous recombinant human erythropoietin and autologous blood donation before coronary artery bypass surgery.

Conventional therapies with recombinant human erythropoietin (rHuEPO) to sustain preoperative autologous blood collection entail high doses of the drug at short intervals. To evaluate the efficacy of a single weekly dose of rHuEPO for autologous blood collection, we randomly assigned 24 male patients scheduled for coronary artery bypass surgery to receive 400 IU/kg rHuEPO subcutaneously once a week or iron only. Patients were examined weekly and a total of up to 4 units of autologous blood were obtained if the hemoglobin level exceeded 12 g/dL. Patients receiving rHuEPO had consistently higher hemoglobin values than those receiving iron only (P < 0.001). Consequently, more autologous red cells were obtained from this group (776 +/- 49 mL vs 682 +/- 91 mL; P < 0.05). One patient receiving rHuEPO and eight in the control group required homologous blood at surgery (P < 0.01). These results suggest that 400 IU/kg rHuEPO administered subcutaneously once a week efficiently stimulates erythropoiesis and compensates the hemoglobin decrease after autologous blood donation.

Blood Transfusion, Autologous↗

Prospective evaluation of clinical scoring systems in infants and children with cardiopulmonary insufficiency after cardiac surgery.

OBJECTIVE: To document severity of illness and to evaluate the predictive value of clinical scoring systems in infants and children with cardiopulmonary insufficiency after cardiac surgery. DESIGN: Prospective study with follow up to hospital discharge. SETTING: A multidisciplinary pediatric ICU in a University Hospital. PATIENTS: Between 1/1989 and 4/1992 441 infants and children with congenital heart disease underwent open heart surgery. 128 of these patients developed postoperative cardiopulmonary insufficiency and were entered into this study. METHODS: Data relevant to the Acute Physiologic Score for Children (APSC), Pediatric Risk of Mortality (PRISM), Therapeutic Intervention Scoring System (TISS) and Organ System Failure (OSF) score were collected in all patients during the first 4 days of postoperative intensive care. RESULTS: The mean age of the patients was 1.5 +/- 0.2 years. The mean duration of mechanical ventilation and ICU care was 6.2 +/- 0.6 and 8.1 +/- 0.7 days, respectively. On the first postoperative day the mean APSC and PRISM scores of survivors and nonsurvivors were 13.9 +/- 1.3 vs 24.5 +/- 1.3 (p < 0.001) and 6.1 +/- 0.5 vs 19.6 +/- 1.9 (p < 0.001), respectively. The mean TISS and OSF scores of survivors and nonsurvivors were 46 +/- 0.8 vs 57.8 +/- 1.4 (p < 0.001), and 2.2 +/- 0.2 vs 3.4 +/- 0.2 (p < 0.001), respectively. The overall hospital mortality rate was 9.9%, the hospital mortality rate of patients with postoperative cardiopulmonary insufficiency 34%. Patients with an APSC score < 10 and a PRISM score < 5 had a survival rate of 100%, whereas patients with an APSC score > 30 and a PRISM score > 25 had a mortality rate of 100%. The area under the receiver operating characteristic (ROC) curve for APSC, PRISM and TISS was 0.847, 0.826 and 0.793, respectively. CONCLUSION: APSC, PRISM and TISS describe accurately severity of illness in infants and children with cardiopulmonary insufficiency after cardiac surgery and all scores identify those patients at increased risk for mortality.

Cardiac Output, Low↗

Preoperative prostaglandin E1 treatment to prevent right ventricular failure after orthotopic heart transplantation.

Elevated pulmonary vascular resistance (PVR) and pulmonary hypertension (PH) are high risk factors for early graft failure in orthotopic heart transplantation (oHTx). The need for an oversized donor in patients with elevated PVR aggravates the shortage of suitable donor organs. To decrease the elevated PVR to values suitable for orthotopic heart transplantation prostaglandin E1 (PGE1) was administered in 11 patients (11 male, mean age 49.2 years, mean dosage 35 ng/kg per min over 6-8 days). Ten days after the discontinuation of the PGE1 therapy, recatheterization was done. All haemodynamic data were determined by right heart catheterization using a Swan Ganz catheter and thermodilution technique before, and 10 days after, PGE1 treatment. The Wilcoxon signed ranks test was used for statistics. PVR significantly decreased in all patients (5.5 to 2.8 Wood units, P < 0.005). All patients were considered to be suitable for oHTX and put on the waiting list. At the time of writing, in eight of these patients (eight male, mean age 49.6 years; four ischemic, four dilatative CMP) oHTX had been successfully performed. No right ventricular failure occurred in the postoperative phase. These results sugest that long-term moderation of elevated PVR by PGE1 therapy weeks or months before transplantation enables oHTX in patients with elevated PVR.

Adult↗

Transoesophageal echocardiography during removal of a caval filter in a patient at high risk of massive pulmonary thromboembolism.

A new type of vena caval filter was to be removed from a woman who had a high risk of massive pulmonary thromboembolism because of extensive thrombus in the iliac vein incorporating the filter. The removal was performed under general anaesthesia in the cardiac operating theatre using transoesophageal echocardiography to monitor the right heart and the pulmonary artery during the critical phase of removal. The manoeuvre succeeded with only insignificant embolisation occurring, and that was identified by transoesophageal echocardiography.

Echocardiography↗

Open heart surgery in children of Jehovah's Witnesses: extreme hemodilution on cardiopulmonary bypass.

Between January 1979 and July 1989, 15 children of Jehovah's Witnesses underwent corrective open surgery for congenital heart disease (CHD) on cardiopulmonary bypass (CPB). Ages ranged from 1.5-17 years and body weight from 9.1-63 kg, with five patients weighing less than 15 kg. Eight children were cyanotic, and two of them had had previous thoracic operations. All operations were performed in moderate to deep hypothermia using a modified version of isovolemic hemodilution with bloodless priming technique of extracorporeal circulation. Mean hematocrit levels decreased from 47.3% (36.9-70%) to 34.6% (27.2-49.1%) after hemodilution, and then to 17.9% (10.5-25.6%) during bypass. They increased again to 34.1% (24.4-50%) at the end of the operation and to 33.4% (25.1-40%) on day 12. All intra- and postoperative hematocrit levels were significantly lower (p less than 0.001). There was one postoperative death, not related to the technique. Our results demonstrate that bloodless cardiac surgery on bypass is feasible in children as shown in this special group of children of Jehovah's Witnesses. Knowing the risks of homologous blood transfusion this technique should be used more extensively in the future.

Adolescent↗

Postoperative myocardial ischaemia in patients with recent myocardial infarction.

Fifteen patients (10 men and five women; mean age 67.3 yr) with a history of a recent (less than 1 yr) myocardial infarction underwent ambulatory ECG monitoring for 5 days after non-cardiac surgery. The duration, number and severity of ischaemic episodes were maximal within the first 12 h after surgery and again on the 3rd day after operation. The difference in the duration of ischaemic episodes between the 2nd and 3rd days after operation was statistically significant (P less than 0.05). There were no perioperative myocardial infarctions and all patients were discharged from hospital.

Aged↗

Continuous extracorporeal fluid removal in children with low cardiac output after cardiac operations.

Eleven hypervolemic and oliguric children with low cardiac output after cardiac operations were treated by slow continuous ultrafiltration or continuous arteriovenous hemofiltration. A mean negative fluid balance of 1.63 +/- 0.37 ml/kg/hr (standard error of the mean [SEM]) significantly improved the hemodynamic status within 59 +/- 6.1 hours (SEM). Although the central venous pressure decreased significantly from 15.2 +/- 0.84 to 8.8 +/- 0.92 mm Hg (p less than 0.0001), the mean arterial pressure increased significantly from 41.5 +/- 2.54 to 53.5 +/- 2.21 mm Hg (p less than 0.001). In addition, pH increased significantly from 7.31 +/- 0.01 (SEM) to 7.43 +/- 0.001 (SEM) (p less than 0.001) and oxygenation index (arterial oxygen tension/inspired oxygen fraction) from 119 +/- 15.2 (SEM) to 214 +/- 27.0 (SEM) (p less than 0.001). Hemodynamic improvement during slow continuous extracorporeal fluid removal allowed a significant decrease of the catecholamine infusion rate. After normovolemia had been achieved, continuous arteriovenous hemofiltration had to be continued in four children because of persistent anuria. Eight patients could be weaned from artificial ventilation and vasopressor support. Two patients died without recovery of renal function and one with restored renal function. Slow continuous ultrafiltration and continuous arteriovenous hemofiltration improve the cardiovascular function in children with low cardiac output by optimizing the preload conditions of the failing heart. In addition, they improve acid-base balance and pulmonary gas exchange.

Blood Pressure↗

[Preoperative risk assessment: long-term electrocardiography for directed diagnosis of arrhythmias].

The role of ambulatory electrocardiography for detection, confirmation, or exclusion of severe forms of arrhythmias was investigated in our preoperative anesthesia clinic. In a prospective study over a period of 21 months, 30 of 8935 preoperatively evaluated patients (0.3%) scheduled for noncardiac surgery were monitored by 24-h ambulatory ECG. Indications included common clinical reasons for ordering an ambulatory ECG and additional specific "anesthesiologic" indications: Syncopes, dizziness, or other manifestations possibly related to cardiac arrhythmias; Rhythm disturbances under antiarrhythmic drug therapy; Suspected paroxysms of supraventricular tachycardia; Q-T syndrome, R- on-T phenomenon; Insignificant rhythm disturbances in patients with significant cardiac disease such as cardiomyopathy, aortic stenosis, mitral valve prolapse; Rhythm disturbances in patients with poor general medical status; Recent myocarditis with arrhythmias; Previous known or suspected intraoperative cardiac complications; Suspected sick sinus syndrome. The mean age of the patients was 63.9 years; most (24/30) were classified as ASA III. In 4 patients with suspected bradycardic rhythm disturbances the ambulatory ECG proved a useful method for further decision-making compared to the routine resting ECG. According to the long-term ECG recordings 22 patients were classified as Lown IV. After effective antiarrhythmic therapy--usually with propafenon--none of these patients (n = 13) or those classified as Lown 0 to III (n = 8) showed intraoperative arrhythmias or other hemodynamic problems. In contrast, of the patients with complex rhythm disturbances refractory to antiarrhythmic drug therapy (n = 4) or those in whom emergency operations were performed without antiarrhythmic drug therapy (n = 2), 4 developed severe arrhythmias or other intraoperative hemodynamic problems. Two died on the 1st postoperative day.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗