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Biomedical subjects

W Engelhardt

Publications and source records attributed to W Engelhardt.

At least 19 recordsLinked to original sources
PubMed2001

Systemic right ventricular failure after atrial switch operation: midterm results of conversion into an arterial switch.

BACKGROUND: Failure of the systemic right ventricle after atrial switch operation can be treated by conversion into an arterial switch operation. METHODS: Four patients, age 38 to 59 months, presented with right ventricular failure after Senning operation and ventricular septal defect closure. One patient had elevated left ventricular pressure; in the other three patients the left ventricle was retrained to a left ventricular/right ventricular pressure ratio of 0.8 or greater by pulmonary artery banding in 12 to 24 months. RESULTS: Postoperative course after arterial switch operation was prolonged, but clinical condition was good at discharge. Fractional shortening ranged from 20% to 28%. Trace-to-moderate aortic regurgitation was present; only 1 patient had preserved sinus rhythm. After a mean follow-up of 43.5 months 1 patient had died due to left ventricular dysfunction. The survivors are in New York Heart Association functional class I to II. Fractional shortening has improved (29% to 37%); aortic regurgitation has not increased. No patient has undisturbed sinus rhythm. CONCLUSIONS: Conversion of an atrial into an arterial switch is an alternative to cardiac transplantation in childhood. However, the procedure is demanding. Long-term morbidity is caused by rhythm disturbances. Aortic valve performance and left ventricular function require close observation.

Cardiac Surgical Procedures↗
PubMed2000

Anatomical risk factors for mortality and cardiac morbidity after arterial switch operation.

BACKGROUND: The arterial switch operation (ASO) is the treatment of choice for transposition of the great arteries. METHODS: Anatomical risk factors on mortality and morbidity were analyzed retrospectively in 312 patients who underwent ASO between 1982 and 1997. RESULTS: Survival was 95%, 92%, and 92% after 30 days, 5, and 10 years, respectively. Operative survival improved after 1990 to 97% (p < 0.001). Risk factors for operative mortality were complex anatomy (p = 0.018), coronary anomalies (p = 0.008), and prolonged bypass time (p < 0.001). Determinants of late mortality were coronary distribution (p = 0.03), position of the great arteries (p = 0.0095), bypass time (p = 0.047), and aortic coarctation (p = 0.046). After a follow-up of 3.6 +/- 2.7 years (0.1 to 14.9 years), 98% had good left ventricle function, 94% were in sinus rhythm, 2.4% had moderate to severe pulmonary stenosis, 0.3% had significant aortic regurgitation, and 1% had coronary stenosis. Freedom from reoperation was 100%, 96%, and 94% after 1, 5, and 10 years, respectively. No preoperative anatomic parameter correlated with long-term morbidity. CONCLUSIONS: ASO can be performed with low operative mortality (< 5%) and long-term morbidity. Malformations associated with complex transposition of the great arteries influence early and late mortality.

Cause of Death↗
PubMed1999

Experience with an adjustable pulmonary artery banding device in two cases: initial success--midterm failure.

Retraining of the left ventricle in congenitally corrected TGA or after Senning or Mustard operation is necessary when right-ventricular failure is developing and an arterial switch operation is indicated. As these hearts have little tolerance of marginal overbanding, a long-term adjustable pulmonary artery banding device would lower stress and risk of training. Although the inserted device (Osypka) allowed convenient intraoperative pressure ratio adjustment, mid-term adjustment failed due to dysfunction of the system.

Cardiac Surgical Procedures↗
PubMed1998

[Recovery time after (S)-ketamine or ketamine racemate. Recovery time after short anesthesia in volunteers].

UNLABELLED: The anaesthetic potency of the (S)-ketamine isomer is approximately double that of racemic ketamine. The aim of this study was to compare the recovery of cerebral function after a bolus of 1.3 mg/kg racemic ketamine or 0.65 mg/kg (S)-ketamine followed by continuous application of 4 or 2 mg/kg x h over 15 minutes. METHODS: With their informed consent and approval of the local ethics committee 12 healthy volunteers were enrolled in a double-blind, cross-over study. All drugs were dissolved in identical volumes. On three dates with an interval of one week at least ketamine/NaCl, (S)-ketamine/physostigmine or (S)-ketamine/NaCl was administered (table 1). The sequence was randomized. In addition, the unspecific antagonistic potential of the centrally acting, cholinergic agonist physostigmine (0.012 mg/kg) after (S)-ketamine was tested against saline-placebo. Neuropsychological tests (tests 3-5 of the syndrome-short-test [Erzigkeit, see references]) were used to quantify cerebral function before and at 45, 75, 105, 135, 165 and 195 min after anaesthesia. All data are mean values and standard deviation. Comparisons over time and between drugs were carried out using two-dimensional analysis of variance (ANOVA). Wilcoxon-tests were used post-hoc. p < 0.05 was considered significant. RESULTS: After (S)-ketamine the subjects were able to carry out the tasks more rapidly than after racemic ketamine (p < 0.05). Mean time to reach preoperative test performance +10% was 117.5 min for (S)-ketamine/physostigmine, 121.3 min for (S)-ketamine/NaCl and 141.6 min for racemic ketamine (p < 0.05 between (S)-ketamine and racemic ketamine). No differences were found between physostigmine and placebo. The incidence of side effects (mainly nausea, vomiting) was not different. DISCUSSION: (S)-ketamine offers a shorter recovery time after short anaesthesia compared to racemic ketamine. The investigated dose of physostigmine was probably too low to produce antagonism of (S)-ketamine. An increased dosage of physostigmine has yet to be studied, but is likely to cause a higher rate of side effects such as nausea, vomiting, bradycardia and possibly even tonic-clonic seizures.

Adult↗
PubMed1998

Pericardial effusions in infants and children: injection of echo contrast medium enhances the safety of echocardiographically-guided pericardiocentesis.

Pericardiocentesis is usually an easy and uncomplicated procedure when guided by cross-sectional echocardiography, but an abnormal intracardiac or extrapericardial position of the puncture system can occur, especially in children. Injection of echo contrast medium through the puncture needle is a very sensitive, quick, easy and harmless procedure which can be performed at the bedside in all cases in which doubt remains concerning the location of the needle. Prompt enhancement of signal intensity of the pericardial fluid validates the correct intrapericardial position, and permits visualization of the tip of the needle. Absence of echodense formations excludes an intrapericardial position. We recommend the use of echo contrast medium during pericardiocentesis whenever blood is aspirated through the needle, or if there is any doubt concerning its location.

Adolescent↗
PubMed1998

[Problems with infusion of vasoactive drugs].

An infusion system that is insufficiently equipped with an alarm device in case the syringe pumps are obstructed, may gravely endanger patient safety. In a patient with septic shock, an obstruction of the infusion system led to periodic application of norepinephrine boli. Sudden haemodynamic disturbances in critically ill patients should be evaluated for pathological causes as well as for technical failure in the infusion system. A sensitive alarming system of syringe pumps may help to eliminate inappropriate drug delivery. For safe infusion of vasoactive drugs the following conditions are highly recommended: a singular syringe pump, a high volume delivery at a low drug concentration, a pressure-controlled infusion device and a short and pressure-resistant infusion system.

Blood Pressure↗
PubMed1997

Influence of heavy metal ions on antibodies and immune complexes investigated by dynamic light scattering and enzyme-linked immunosorbent assay.

The effect of Cd2+, Pb2+, Hg2+ and Cu2+ on the aggregation behaviour of monoclonal rat-IgG1-anti-mouse antibodies (kappa-light chain specific) and their antibody-antigen complexes with monoclonal mouse-IgG1 is reported. Investigations were done using the dynamic light scattering method. Cd2+ ions affected the hydrodynamic properties of the antibodies and the immune complex formation very little. More than 4 Cu2+ ions per antibody molecule led to large insoluble aggregates. Pb2+ ions also interacted with antibodies and immune complexes. Instead of "monomeric' antibodies (Ab) or immune complexes (Ab1Ag1), large soluble aggregates were detectable in the solution. Hg2+ ions induced complex formation with 3-4 antibodies per aggregate. Possible kinds of interaction are discussed. Additionally, we tested the antigen binding activity of metal-treated antibodies in ELISA-tests. The Sandwich ELISA technique was used to investigate the serological activity of the metal-treated antibodies, i.e., the reaction with the specific antigen. For these experiments we used the same monoclonal antibodies, mouse-IgG1 and rat-IgG1-anti-mouse. The influence of the above mentioned heavy metal ions was investigated up to a 10-fold molar excess over the antibody concentration. Even at these "unphysiological' high metal ion concentrations an inhibition of the antibody-antigen binding activity was not detectable.

Antibodies, Monoclonal↗
PubMed1997

[Recovery and psychomimetic reactions following S-(+)-ketamine].

Ketamine is a racemic mixture containing equal parts of S-(+)-ketamine and R-(-)-ketamine. Their potency relation is approximately 4:1. In early human studies S-(+)-ketamine was presumed to produce the desired anaesthetic effects and R-(-)-ketamine the undesired psychic emergence reactions. Therefore, ketamine was compared in a number of randomised studies in volunteers and patients with racemic ketamine. This review addresses the impact of S-(+)-ketamine on recovery from anaesthesia, incidence and content of vivid dreams, and other side effects. The dose relation applied in the studies was 1:2. With only one exception, the recovery phase was clearly shorter after S-(+)-ketamine compared to racemic ketamine irrespective of its application as a single bolus, a bolus followed by continuous infusion, or an intramuscular injection. However, the incidence of psychic emergence reactions was lower after S-(+)-ketamine in only a single study. In conclusion, S-(+)-ketamine should be always combined with a hypnotic or sedative drug in clinical anaesthesia.

Anesthesia Recovery Period↗
PubMed1997

Trial of pulmonary artery banding: a diagnostic criterion for 'one-stage' arterial switch in simple transposition of the great arteries beyond the neonatal period.

OBJECTIVE: Arterial switch operation (ASO) is the procedure of choice for the repair of simple d-transposition of the great arteries (TGA) during the neonatal period. Beyond this time such correction is performed in two stages. The first step incorporates banding of the pulmonary artery with or without a Blalock-Taussig shunt to train the left ventricle (LV). The second step consists of the ASO. To find out whether candidates for a two-stage procedure would tolerate a one-stage correction, a trial of pulmonary artery banding was performed. MATERIAL AND METHODS: Between February 1986 and December 1995, 224 patients less than 3 months of age with TGA, intact ventricular septum or a small restrictive ventricular septal defect, had an ASO. Seven patients were 4 weeks of age or older (28-70 days). Two of these had a pulmonary artery to systemic pressure ratio higher than 0.6 and underwent primary ASO without complications. The remaining five patients had low left ventricular pressure with a pulmonary to systemic pressure ratio of 0.2-0.5; echocardiography showed a banana-shaped LV with left ventricular wall thickness as low as 3 mm. They underwent a trial of pulmonary artery banding to systemic pressure for 15-30 min. As this increase in workload was tolerated well with an anticipated decrease of oxygen saturation but without hemodynamic disturbances anticipated, the ASO was performed immediately. RESULTS: Postoperative course was uneventful in all five patients, although catecholamine dependence was prolonged and three patients received enoximone. There were no severe complications. Echocardiography showed an increase in posterior wall thickness from 3 to 6 mm after 19 days in one infant. CONCLUSION: Some of the children, assigned for a 'two-stage' ASO may tolerate a primary anatomic repair up to an age of at least three months. This subgroup can be selected by a trial of pulmonary artery banding.

Echocardiography↗