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Biomedical subjects

W A Stertmann

Publications and source records attributed to W A Stertmann.

9 recordsLinked to original sources

[Constrictive pericarditis--surgery with or without heart-lung machine?].

In patients suffering from constrictive pericarditis, the best hemodynamic results can be achieved by total mobilization of the heart and complete resection of the pericardium. Among 72 patients operated upon from 1969 to 1991, the use of extracorporeal circulation became necessary only twice. Therefore, we suggest the use of heart lung machine only in patients with bad myocardial function or in patients who need correction of additional diseases. Routine use of extracorporeal circulation is not mandatory.

Diagnosis, Differential

[Neurologic complications of coronary bypass surgery--a prospective study].

Neurologic, cardiologic, and dopplersonographic findings of 303 patients undergoing coronary bypass surgery were evaluated in a prospective study. About 5% of the patients suffered from a prior stroke. Nearly 9% had a significant stenosis of an internal carotid artery detected by dopplersonography. Central nervous system complications occurred in 18.2% of the patients, predominantly temporary mental disturbances. Old patients and those with complicating heart failure were at higher risk for mental disorders. Approximately 3% of the patients suffered from a stroke with a permanent deficit. Half of them had a potential source of cardiogenic embolism. The risk of a complicating stroke was raised by the presence of a stenosis of a carotid artery, a heart failure, or an arrhythmia. The frequency of peripheral nervous system complications was 13.5% with temporary symptoms in about half of the cases. Brachial plexus paresis predominated with a particular risk in mammaria bypass grafting.

Adult

A modified technique for the production of an arterio-venous shunt in sheep, allowing a comparison of biocompatibility of synthetic materials.

Polytetrafluorethylene (PTFE) prostheses were implanted in 12 sheep as a shunt between the carotid artery and the jugular vein using an end-to-side anastomosis technique. This technique allows repeated tests of the pharmacological and toxicological safety of artificial kidney units after both single and multiple administration. Furthermore, it enables the investigation of detoxification of compounds via dialysis, thus contributing to drug safety. Implantation of the prosthesis was uncomplicated. Connection to the extracorporeal circulation was achieved via catheters and maintained using a pump with an output of up to 300 ml/min. This enabled maintenance of extracorporeal circulation for several hours without clinical impairment to the animals. The AV-shunts remained functional for between 8 and 253 days (mean 112.3 days).

Animals

[Transcranial Doppler sonography during pulsatile and non-pulsatile extracorporeal circulation].

Transcranial Doppler sonography (TCD) was used to determine the mean blood flow velocity of the middle cerebral artery (Vm-MCA) and pulsatility (systolic/diastolic flow velocity = S/D) in 25 patients undergoing aortocoronary bypass grafting before, during, and after extracorporeal circulation (ECC). Preoperatively, none of the patients had signs or symptoms of cerebrovascular disease. ECC was performed with 2.4 l/min per m2 under mild hypothermia (34 degrees C) using membrane oxygenators. After 20 min of nonpulsatile perfusion, ECC was switched to the pulsatile mode for 20 min. Nonpulsatile perfusion was applied for the remaining ECC period. Vm-MCA, S/D, mean arterial blood pressure (MABP), and nasopharyngeal temperature (T.np) were recorded continuously throughout the operation. Hematocrit and paCO2 were determined before, during, and after ECC. Following hemodilution after the introduction of ECC, Vm-MCA was significantly increased compared with the baseline values before ECC. With hematocrit and paCO2 varying insignificantly during ECC, the onset of pulsatile ECC decreased Vm-MCA and MABP simultaneously. After the re-establishment of nonpulsatile ECC, both Vm-MCA and MABP increased again. However, a linear relationship between the two variables could not be documented statistically. During pulsatile ECC, pulsatility (S/D) of the obtained TCD wave forms did not reach baseline values. In 4 cases, TCD showed cessation of diastolic blood flow velocity after induction of ECC or onset of pulsatile ECC. An increase in MABP or changes in ECC regimen promptly restored diastolic TCD signals in these cases. Our results support the concept of increased cerebral blood flow under mild hypothermic ECC. Compared with the nonpulsatile perfusion mode, we found Vm-MCA reduced during pulsatile ECC.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Resection of a heart tumor using autotransplantation.

A 38 year old male patient presented with a cardiac tumor. Echocardiography and visualization of the left atrium revealed a large myxoma. Surgical resection of the tumor was performed with the aid of cardiopulmonary bypass. The extensive size of the tumor base and its localisation at the posterior left atrial wall made a conventional approach impossible. Therefore radical resection of the tumor was undertaken using autotransplantation. After a routine postoperative course, the patient was discharged on the twenty seventh hospital day.

Adult

Laser-assisted trachea anastomoses in dogs.

Tracheal anastomoses are known to be related to special surgical risks. We performed laser-assisted trachea anastomoses in 10 Beagle dogs, using an Argon-laser system and a handheld quarz fiber for energy transmission. All animals showed an uneventful postoperative course without signs of infection, air-leakage or respiratory impairment. Pathologic examination revealed no significant stenosis but a normal reconstruction of the tracheal endothelium and a normal woundhealing with only an increased connective tissue reaction. Because of the lower tensile strength of laser-assisted anastomoses in general, three adapting absorbable sutures should be left in situ to increase the resistance against mechanical stress. Under these circumstances laser-assisted anastomoses seem to be a promising additional method in the field of tracheal reconstruction and transplantation.

Anastomosis, Surgical

Closure of longitudinal sternotomy with absorbable sutures.

In a consecutive series of 150 patients who underwent open heart surgery, absorbable suture (PDS-Ethicon) were used for the closure of median sternotomy. One patient developed sternal dehiscence; wound complications or incompatibility with the suture material did not occur. With the technique of "double" PDS sutures, rapid and secure sternal closure can be performed even in cases of friability of the sternum without cutting through the sternal bone.

Cardiac Surgical Procedures

Pulsatile flow pattern in cerebral arteries during cardiopulmonary bypass. An evaluation based on transcranial Doppler ultrasound.

Pulsatile wave patterns in basal cerebral arteries were studied by means of transcranial Doppler ultrasound (TCD) in 11 patients undergoing cardiopulmonary bypass (CPB) surgery. Different physiological states and technical parameters were demonstrated influencing wave forms delivered from a pulsatile CPB roller pump. The results gave evidence of the variability of pulsatile perfusion which may explain the inconsistency in the literature concerning its effectiveness in preserving tissue function. TCD proved to be a useful approach to define pulsatility of cerebral blood flow during CPB.

Blood Flow Velocity