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Biomedical subjects

J J van der Meer

Publications and source records attributed to J J van der Meer.

14 recordsLinked to original sources

Design and application of sensor for recording sounds over human eye and nose.

The recording of sounds over the orbit of the eye has been found to be useful in the detection of intracranial aneurysms. A hydrophone for auscultation over the eye has been developed and is tested under controlled conditions. The tests consist of measurement over the eyes in three healthy volunteers at rest, during voluntary breathing, during eyeball movements and during sustained orbicular muscular contractions. Furthermore, measurements are performed at the side of the nose. Major features of the hydrophonic transducer are high sensitivity to physiological sounds and a high degree of insensitivity to environmental sounds propagated through the air. It can be concluded that the hydrophone may be useful for the early detection of intracranial aneurysms and also for apnoea detection.

Auscultation↗

Resorbable suture support for ventricular aneurysmectomy.

The edge of tissue left after ventricular aneurysmectomy requires very careful placement and tying of the sutures. The use of Teflon felt as a support appears to redistribute the pressure and thus prevent the sutures from cutting through the vulnerable tissue. In many cases, Teflon felt reinforcement is preferred to direct unsupported closure because of perioperative of immediately postoperative bleeding complications. However, the unavoidable full immobilization of the sutured area, the possible risk of foreign body infection, and the extensive adhesions and calcification in the long term compelled us to search for a better alternative, combining the convenience of both methods and limiting the risks. PDS (polydioxine) resorbable pledgets and strips, provided by Ethicon GmbH, were used as a suture support during the past 2 years for closure of 29 ventricular aneurysmectomies and four ischemic ventricular septal defects, all except one in combination with coronary bypass grafting. The PDS material was easy and efficient to apply and caused no complications during and after the operation. In one case, we had the opportunity to review the supported scar during a second operation for new coronary grafts after 18 months. The formerly feared "linear scar petrification," usual after use of Teflon felt, was absent. The scar was free from difficult adhesions. Our initial experience suggests the further extensive use of this resorbable material as a support for various sutures at risk.

Heart Aneurysm↗

Reoperation for prosthetic heart valve replacement.

From 1974 to 1984, 847 heart valve replacement operations were performed with 1005 prosthetic valves. Thirty-nine (4.6%) were reoperations with 43 prosthetic valve replacements (PVR), on 38 patients. Thirty-three patients had received their initial valve replacement in our hospital and 5 elsewhere. Twenty additional cardiac procedures were required, concomitantly with the prosthesis replacement. Twenty-three patients underwent replacement of a mechanical prosthesis (61%) an average of 4.3 years after initial implantation and 15 patients a bioprosthesis (39%) after 2.8 years. Indications for PVR were endocarditis in 15 patients (39%), prosthesis failure in 13 (34%), periprosthetic leak in 7 (18%), thrombosis in 2 (5%), and a left ventricle subannular aneurysm in 1 (3%). Preoperatively 4 patients were in NYHA functional class II (11%), 15 in class III (39%) and 19 in class IV (50%). Six patients died early postoperatively (15.8%) Various risk factors were analyzed. The early mortality rate was 22% for mechanical prosthesis replacement and 7% for bioprosthesis; 11% for aortic position, 13% for mitral position and 50% to 100% for double valve replacement; 23% for non-elective and 6% for elective operations; 10% for patients with only an initial valve replacement and 43% with additional previous valve operations; 18% for active endocarditis, 15% for prosthesis failure, 14% for periprosthetic leak, 0% for thrombosis and 100% for subannular aneurysm; 0% for patients in class II, 7% in class III and 26% in class IV; 6% in patients with an aortic cross-clamp time less than 2 hours and 24% with more; 27% prior to 1981 and 9% during the last 4 years; and finally 50% in patients over the age of 60.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Traumatic rupture of the thoracic aorta.

The experience in the surgical treatment of traumatic rupture of the thoracic aorta is discussed. Twenty-two patients were seen from 1970 to 1980. They were divided into three groups, according to delay between injury and aortic repair: 1 degree emergency group: 16 patients; 2 degree delayed group: 3 patients; 3 degrees chronic group: 3 patients. All patients had a widened mediastinum and the aortography confirmed the diagnosis. In the first group four patients died before surgery could be started and four after aortic repair from 10 days to 6 seeks postoperatively. In the second and third group all patients survived. Of 22 cases, 21 ruptures were located at the aortic isthmus and 1 at the aortic arch. Many patients had various other injuries, skeletal, abdominal or cerebral. All, but one patient, were operated with the aid of a partial pulsatile left heart bypass to avoid cerebral hypertension and cardiac overload, and to prevent kidney and spinal cord ischemia. One patient was operated, according to the method of Crawford, with blood pressure controlled with nitroprusside. We have not observed in our patients paresis or paraplegia after surgery. The hospital mortality of the surgical treated patients was 34% in the emergency group and 0% in the delayed and chronic group. Surgical treatment is essential in emergency situation, as a complete rupture may be fatal and repair of the chronic post-traumatic false aneurysm is advocated, as their prognosis is unpredictable.

Aorta, Thoracic↗