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Biomedical subjects

G Trittenwein

Publications and source records attributed to G Trittenwein.

At least 37 records · Page 2Linked to original sources
PubMed1999

Lipid peroxidation during initiation of extracorporeal membrane oxygenation after hypoxia in endotoxemic rabbits.

Initiation of extracorporeal membrane oxygenation (ECMO) in septic children with severe respiratory failure often improves oxygenation but not pulmonary function. The factors affecting pulmonary function following onset of ECMO are not completely understood, but are thought to involve injury mediated, in part, by reactive oxygen species. We hypothesized that induction of ECMO using 100% oxygen as the sweep gas through the oxygenator would increase lipid peroxidation in endotoxin-primed animals after severe hypoxia. We further speculated that provision of oxygenated blood to the pulmonary circulation via venovenous ECMO would promote a greater degree of oxidative damage to the lung as compared to venoarterial ECMO. Eighteen New Zealand White rabbits were assigned to a control group (control) or two intervention groups subjected to 60 min of venoarterial or venovenous ECMO. ECMO was initiated following an intravenous challenge with 0.5 mg/kg of E. coli endotoxin and a period of global hypoxia leading to an arterial pH of 6.99 +/- 0.09, PaCO2 of 103 +/- 31 mmHg and PaO2 of 27 +/- 5 mmHg. Malondialdehyde (MDA), a marker of lipid peroxidation, was measured in lung tissue homogenates and in arterial plasma. Lung tissue MDA demonstrated a strong trend towards an increase in the venoarterial group (1884 +/- 945 nmol/g protein) and in the venovenous group (1905 +/- 758 nmol/g protein) in comparison to the control group (644 +/- 71 nmol/g protein) (p = 0.1; significance at 95% in Scheffe test). Lung tissue MDA in the venovenous group had a significant correlation with mean PaO2 during ECMO by regression analysis (r2 = 0.678, p = 0.044). The change in blood MDA concentration between pre-ECMO and post-ECMO values was greater in the venovenous group (pre 1.62 +/- 0.61 versus post 5.12 +/- 0.2.07 mumol/l, p = 0.043) compared with that seen in the venoarterial group (pre 1.46 +/- 0.38 versus post 3.9 +/- 0.93 mumol/l). Our data support the hypothesis that initiation of ECMO with a circuit gas oxygen concentration of 100% after global hypoxia enhances oxidative damage to lipids in endotoxin-challenged animals. During venovenous ECMO this finding is dependent on PaO2.

Animals↗
PubMed1998

A simple neonatal mock circulation enabling pulsatility and different hemodynamical states for neonatal ECMO research: application to assess the effect of a centrifugal pump operated neonatal ECMO system on the circulation.

In neonates, extracorporeal membrane oxygenation (ECMO) is increasingly used for circulatory support, e.g., after cardiac surgery. For training purposes and for research, animal experiments are usually required, complicated by increasing social issues, high costs, and limited reproducibility. Therefore, we designed a mechanical neonatal mock circulation (NMC) model enabling pulsatility and various hemodynamic conditions commonly occurring in neonates. Connected to a flow and pressure reading interface, a computer assisted data management system was installed. A nonocclusive roller pump combined with stiff and elastic tubing segments (for aortic pressure regulation and venous capacity) as well as constant and variable resistance (and optionally a patent duct) are essential features of the NMC system. To show the investigational potential, we studied the influence of venoarterial and venovenous ECMO on the NMC performance during normal circulation, hypovolemia, high arterial resistance, the combination of both, and in low cardiac output. By assessing the significant effects of ECMO on the circulatory function of the NMC, its feasibility and investigational properties could be demonstrated.

Blood Pressure↗
PubMed1997

Preoperative ECMO in congenital cyanotic heart disease using the AREC system.

BACKGROUND: In cyanotic congenital heart disease, oxygen delivery is impaired either by reduced pulmonary perfusion or by limited entry of oxygenated blood into the systemic circulation. Additional impairment of oxygen delivery (eg, in pulmonary hypertension) leads to hypoxic cerebral damage. Preoperative extracorporeal membrane oxygenation enables oxygenation in otherwise untreatable cases. METHODS: In 3 neonates suffering from cyanotic congenital heart disease (1 with tricuspid atresia and 2 with transposition of the great arteries) with arterial desaturation despite application of prostaglandins, balloon atrioseptostomy, and eventually inhaled nitric oxide during intermittent positive-pressure ventilation with an inspired oxygen fraction of 1, oxygenation could only be established by means of preoperative extracorporeal membrane oxygenation. We used a venovenous single-lumen cannula tidal-flow extracorporeal membrane oxygenation system described by Chevalier and associates that has previously been used for extracorporeal lung support. In this system, called AREC (assistence respiratoire extra-corporelle), alternating clamps and a nonocclusive roller pump were used. RESULTS: All 3 survived. CONCLUSIONS: We conclude that the AREC system enables sufficient preoperative oxygenation in patients with cyanotic congenital heart disease and hypoxia in spite of all conventional therapeutic means. This provides a stable preoperative condition for elective palliation or correction.

Cyanosis↗
PubMed1997

Single needle venovenous extracorporeal membrane oxygenation using a nonocclusive roller pump for rescue in infants and children.

In 1993, J.Y. Chevalier described a single needle venovenous extracorporeal membrane oxygenation (ECMO) system using a nonocclusive roller pump and alternating clamps for pulmonary support in neonates. We modified this system to use it in older children as well and for additional indications. Introducing a double raceway and 2 different sizes of tubing sets and performing percutaneous approach, we treated 21 children (age 1 day to 49 months) using this system. Indications for treatment were hypoxia and hypoxic induced myocardial dysfunction resulting from pulmonary failure, sepsis, and congenital defects. Of the children treated for neonatal indications, 7/9 survived. For 2 children ECMO was terminated because of intraventricular hemorrhage (IVH). In the pediatric group 5/7 of the children could be weaned from ECMO, and 2 children died after more than 30 days on ECMO. Two of the children who had been almost completely weaned died later because of therapy withdrawal following a brain death diagnosis. In the cardiac group, 3/5 of the children survived. We conclude that the described system is an effective venovenous ECMO system that reduces invasivity and expenditure.

Anticoagulants↗
PubMed1997

Extracorporeal membrane oxygenation in neonates.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO), originally developed as an artificial replacement for respiratory assistance, is decreasingly used in neonates with respiratory failure. Nevertheless, there is a constant need for this invasive and expensive neonatal treatment modality. INTERVENTION: Review of our experience (80 recent ECMO performances because of circulatory failure) and the literature. RESULTS: In contrary to reduced ECMO performances out of respiratory insufficiency in neonates, ECMO as circulatory support is increasingly used. Neonatal sepsis, pre- and postoperative cardiac failure, combined circulatory and respiratory failure after resuscitation and with congenital diaphragmatic hernia result in a permanent need for ECMO, whenever there are fewer ECMO treatments per year. Nonocclusive pumps, portable devices, small priming volumes and tapered anticoagulation protocols enable survival through ECMO even in virtually hopeless hemodynamic conditions. Special efforts in investigation and prevention of permanent neurological impairment, especially after severe pre-ECMO hypoxia seem to be mandatory. CONCLUSION: ECMO remains an important tool in neonatal and pediatric intensive care. However, the number of ECMO therapies was reduced due to respiratory therapeutic progress, but indications and ECMO technology have changed.

Anticoagulants↗
PubMed1995

Agmatine and spermidine reduce collagen accumulation in kidneys of diabetic db/db mice.

In the present study, we tested the hypothesis whether agmatine and spermidine, metabolites of arginine metabolism, share the pharmacological activities of arginine reducing collagen accumulation in the diabetic kidney. Eleven db/db mice were administered agmatine and 12 db/db mice spermidine (50 mg/kg body weight). Ten db/db mice received no treatment as negative controls and 10 db/db mice were treated with aminoguanidine (50 mg/kg body weight) as positive controls. Mean kidney OH-proline content reflecting kidney collagen content and mean CML concentration were significantly higher but acid solubility of collagen significantly lower in the untreated group than in the treated groups. Agmatine, although missing the alpha-amino group and the carboxyl group, and spermidine, although missing the guanidino group, thus still revealed the arginine activity. We hypothesize that the strongly nucleophilic structure of polyamines common to all active compounds is able to block reactive carbonyls.

Agmatine↗
PubMed1995

[Acute respiratory failure (ARDS) in a young child after drowning accident: therapy with exogenous surfactant and high frequency oscillatory ventilation].

The adult respiratory distress syndrome (ARDS) in children has a very poor prognosis with a mortality risk of between 55 and 85%, in spite of improvements due to the introduction of positive endexpiratory pressure ventilation. We describe the clinical course of a not yet 3 year-old boy with severe ARDS following near-drowing. Treatment with exogenous surfactant and high frequency oscillatory ventilation, a well-established procedure in neonatology, was responsible for the favorable outcome. The high cost of surfactant therapy, however, is the main limiting factor for this kind of treatment in children beyond the neonatal period, but it may be the last therapeutic resort in the management of severe ARDS.

Child, Preschool↗
PubMed1986

[Heart function in infants and small children, whose mothers required tocolysis with hexoprenaline sulfate (Gynipral)].

Cardiac function was investigated in 23 retrospectively selected children (mean age 15 months, range 2/12-3 4/12), whose mothers had undergone a successful course of tocolysis around the 31st week of pregnancy. Hexoprenaline sulfate (Gynipral) had been given at a mean cumulative dose of 51,103 micrograms over an average period of 13.8 days. The infants were born at term; cases with marked birth asphyxia, low birth weight or other perinatal problems possibly influencing cardiac performance were not included. The examination included a chest X-ray, ECG (all standard leads) and ultrasonography. There was no evidence of myocardial dysfunction which might have been the late result of untoward effects of the beta 2-mimetics given during the last trimester of pregnancy. All probands were normally developed: on cardiological examination an incidental systolic murmur was found in 2 infants and border-line cardiomegaly in another proband. ECG revealed a wandering pace-maker and occasional ventricular extrasystoles in one 3 month-old boy, which is not necessarily abnormal at this age. Two-dimensional echocardiography showed normal cardiac anatomy in all 23 probands. One-dimensional M-mode showed normal left ventricular function parameters. The slightly elevated myocardial contractility demonstrated by means of the M-mode was attributed to increased sympathetic tone in the non-sedated children.

Child, Preschool↗
PubMed1985

[2-dimensional echoencephalography in childhood: method, indications and personal results].

Two-dimensional echoencephalography has become an important diagnostic tool in paediatric neurology. The clinical value of two-dimensional echoencephalography in children is discussed on the basis of the results of 669 own ultrasonic examinations. Improvements in equipment and handling, as well as increasing experience enabled a firm diagnosis in most cases. However knowledge of ultrasound morphology and correlation of these pictures with clinical findings and prognosis are necessary for the successful application of this new method.

Anencephaly↗
PubMed1985

[Supportive measures in aggressive cytostatic therapy].

Over the past years significant progress has been made in the treatment of childhood cancers due to newer and more intensive chemotherapeutic regimes. However, with the increased intensity of chemotherapy, more treatment related complications are seen, requiring also more aggressive supportive care. The major complications of the cytotoxic treatment are bone marrow aplasia, immunosuppression, vomiting, anorexia and weight loss and supportive measures as adequate blood component supply, prophylaxis, recognition and effective treatment of infections as well as parenteral hyperalimentation are corner stones of modern cancer therapy. Blood sampling, application of blood products or intravenous drugs and continuous parenteral nutrition is easily performed using a central venous line. Our experience with the continuous venous access of central lines in patients receiving aggressive cytotoxic treatment did not show a higher incidence of infectious complications but had significant advantages in the supportive care.

Anemia, Aplastic↗
PubMed1984

[Cross sectional echoencephalography in infants].

Importance of echoencephalography increased during development of neonatal intensive care. In addition to investigations in neonates 2-D-echoencephalography even during pregnancy and infancy can be used for detection of intracranial pathology. A standardized method of investigation and the knowledge of the pathology of the expected lesions are of fundamental importance. During neonatal period and infancy intraventricular and subdural hemorrhage, brain tumors, postinfection sequelae, hypoxic brain damage, alteration of intracranial perfusion and cerebral malformations can be detected.

Age Factors↗
PubMed1984

[Immunosuppressive therapy in congestive cardiomyopathy in childhood].

Two patients aged ten and fourteen years presented with clinical signs of acute viral myocarditis and cardiac failure. Within three months both showed clinical deterioration with development of severe mitral and tricuspid incompetence. From their third month of illness myocardial antibodies were constantly found by indirect immunofluorescence technique. Both were treated with prednisone 2 mg/kg/d and azothioprine 2-2,5 mg/kg/d from their ninth and third month of illness for fifteen and twelve months respectively. Both showed considerable improvement within weeks with resolution of their valve incompetence, diminution of heart size and normalization of their ECGs. Results from myocardial biopsies suggest that a number of patients with chronic congestive cardiomyopathy may have long lasting viral inflammation of the myocardium or myocardial fiber destruction by autoimmunmechanisms after viral infection. Our cases probably had acute myocarditis which led to chronic congestive cardiomyopathy. Immunosuppressive therapy seems to be justified in cases where chronic inflammation or destruction of the myocardium is suspected because of the results of cardiac biopsies, myocardial scintigraphy or demonstration of myocardial antibodies.

Adolescent↗
PubMed1983

[Chronic fetomaternal transfusion].

Transplacental feto-maternal hemorrhage was diagnosed after delivery of a highly anemic infant from a healthy mother with polyhydramnios by demonstration of fetal red cells in the maternal circulation (145 degrees/00) using a modified Kleihauer technique. Other causes for anemia such as hemolysis, coagulopathies, failure of red cell production or perinatal posttraumatic bleeding were excluded. The transfused volume estimated eexceeded the blood volume of the newborn by several times, thus indicating a chronic blood loss. This was confirmed by hematologic data typical for a normovolemic anemia, a low serum iron level and the development of a congestive heart failure in the newborn infant.

Adult↗
PubMed1983

[Percutaneous-peripheral vena cava catheterization in intensive care of premature and newborn infants. Comparison of Shaw's silastic catheter with the customary polyvinyl catheter].

Central venous catheters inserted via peripheral veins are commonly used in neonatal intensive care. Handling of two commonly available catheters made of different materials were compared during application in 85 neonates under intensive care. Polyvinylchloride and silicone rubber were used as catheter material. Advantages of silicone rubber catheter were detected especially in very low birth weight premature infants. Successful puncture of the peripheral veins and correct positioning could be performed in a higher proportion of these babies than when using polyvinylchloride-catheters. The insertion of polyvinyl-catheters needs shorter time of manipulation and during infusion we found a significantly lower incidence of mechanical problems with the catheter.

Catheterization↗
PubMedDate not supplied

[Purulent pericarditis during abscess-forming pneumonia].

The case is described of a 6 months old infant who developed purulent pericarditis during the course of pneumonia. Pericarditis probably developed in this condition by contiguous spread from the pleura. Diagnosis of impending cardiac tamponade was masked by the occurrence of massive unilateral empyema. The management of this condition is discussed by open surgical drainage. Real-time two-dimensional echocardiography is useful for diagnosis and surveillance in this disease.

Anti-Bacterial Agents↗
PubMedDate not supplied

[Therapy refractory arterial hypotension after heart operation].

Adrenalin insufficiency associated with adrenal hemorrhage, is a rare complication after cardiac surgery in neonates. A boy suffering from transposition of the great arteries, who had an arterial switch-operation on day three of his life, acquired a bilateral adrenal hemorrhage. Clinically the situation resembled a septic shock. Despite large doses of catecholamines, he continued to have severe arterial hypotension, anuria, and kyperkalemia. The clinical condition did not change, although sepsis specific therapy was initiated. Consequently adrenal insufficiency, as a possible postoperative complication, was considered and prednisolon, initially in a dose of 15 mg/kg/d, was administered. The clinical condition improved dramatically. The diagnosis could be confirmed by ultrasound examination and determination of cortisol and ACTH plasma levels. Adrenal insufficiency was only transitory, adrenal sonography on day 135 returned to normal. The surgical procedure on heart-lung bypass, the obligatory anticoagulation and the perioperative stress have to be considered as pathogenetic factors.

Adrenal Insufficiency↗