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Biomedical subjects

G Herr

Publications and source records attributed to G Herr.

33 records · Page 2Linked to original sources
PubMed1984

Anaesthesia for caesarean section and cerebral aneurysm clipping.

A pregnant patient at 38 weeks gestation presented for a combined procedure of Caesarean section, tubal ligation and cerebral aneurysm clipping. Anaesthesia was induced with thiopental, succinylcholine was administered to facilitate tracheal intubation, and intravenous lidocaine and sodium nitroprusside were used to reduce the hypertensive response to tracheal intubation. Anaesthesia was maintained with nitrous oxide until delivery of the infant, after which time fentanyl, low-dose halothane and pancuronium were added for maintenance of anaesthesia during the neurosurgical procedure. Blood pressure was controlled during the case by administration of a sodium nitroprusside infusion and propranolol. Following completion of the surgical procedures, the patient promptly emerged from anaesthesia and was neurologically normal in the operating room. It is concluded that general anaesthesia can be used satisfactorily for a combined procedure of Caesarean section and cerebral aneurysm clipping.

Adult↗
PubMed1984

Objective evaluation of clinical performance and correlation with knowledge.

In certifying competence of anesthesiologists who have finished residency training, knowledge and judgment are evaluated objectively using written and oral examinations. Clinical motor skills, however, are not routinely assessed by objective techniques. This implicitly assumes that knowledge and judgment correlate with performance of motor skills. This study was designed to evaluate whether performance of a particular motor skill correlates with performance on a knowledge test related to that skill. To do this, we developed a criterion-referenced Spinal Anesthesia Skill Test and a knowledge test using multiple-choice questions related to spinal anesthesia. Both the skill and knowledge tests were administered to 44 residents at various levels of training at five major anesthesia teaching programs. Scores on the skill test were significantly higher than in the knowledge test, suggesting that proficiency in this essential motor skill is achieved earlier in training. There was no correlation between scores on the skill test and knowledge test. There were institution-linked differences in the scores on the skill test, suggesting that teaching of motor skills is not uniform. The advantages of developing criteria of performance of motor skills is discussed.

Anesthesia, Spinal↗
PubMed1981

Performance evaluation: continuous lumbar epidural anesthesia skill test.

The evaluation of skills in anesthesiology residents is usually subjective and lacks demonstrable reliability. Therefore, an objective criterion-referenced skill test for measuring performance of continuous lumbar epidural anesthesia was developed. For such a test to be useful, it is necessary to demonstrate agreement among rater-observers. Eight performances of continuous lumbar epidural anesthesia were recorded on video tape and simultaneously rated by nine anesthesiology faculty observers to determine inter-rater reliability. Inter-rater agreement was analyzed by determining coefficient kappa for each item and the entire test. Coefficient kappa for the entire test was 0.82 indicating a high degree of agreement between raters on the performance or nonperformance of various items. Development and utility of skill tests are discussed.

Anesthesia, Epidural↗
PubMed1978

Droperidol, fentanyl and morphine for i.v. surgical premedication.

Fentanyl 0.1 mg and morphine 10 mg alone and in combination with droperidol 2.5 and 5.0 mg were studied for i.v. surgical premedication in 240 patients. Relief of anxiety, sedation, lack of recall, patient acceptance and side-effects were evaluated. The addition of droperidol to fentanyl and morphine produced greater sedation and relief of anxiety before operation, but did not improve patient acceptance or lack of recall.

Adolescent↗
PubMedDate not supplied

[Improved osseointegration of titanium implants of different surface characteristics by the use of bone morphogenetic protein (BMP-3): an animal study performed at the metaphyseal bone bed in dogs].

AIM: Aim of this study was to determine whether coating of titanium implants of various surfaces with BMP-3 would improve the osseous integration of the implants into the orthotopic bony implant bed. METHOD: In this experimental study 190 micro g per implant of highly purified bone morphogenetic protein 3 (BMP-3) precipitate isolated from porcine bone were available for the coating of each of 24 cylindrical test implants (12 with hydroxyapatite and 12 with plasmapore surface). The remaining 24 test implants with the same surface makeup served as negative controls. Implantation sites were randomly assigned for the 4 versions of implants available and all implants were embedded into the medial or lateral femoral condyle of both legs of 12 German shepherds. The drilling holes were performed in such a matter that after embedding the cylindrical devices a gap of 1 mm surrounding the implants remained. A biomechanical testing and histological evaluation was performed on the explants 42 days after surgery. RESULTS: In biomechanical testing forces necessary to extract the implants from the explanted bones in BMP-3 coated devices were up to 70% higher compared to the ones in the non-coated reference groups. Quantitative histomorphometric examination showed in BMP-3-coated implants an increasing formation of new bone close to their own surface (gap-healing) which was higher than in the corresponding non-coated controls (hydroxyapatite + BMP-3 32.1%, hydroxyapatite controls 20.3%, plasmapore + BMP-3 30.2%, plasmapore controls 13.1%). The extent of direct bone implant contact as percentiles of the corresponding implants perimeter (ongrowth) was also significantly higher in the BMP-3-coated implants compared to the non-coated controls (hydroxyapatite + BMP-3 37.7%, hydroxyapatite controls 22.4%, plasmapore + BMP-3 15.3%, plasmapore controls 6.4%). CONCLUSION: In this study it was proven the first time that implants of various surface textures as used in endoprosthetics are able to be coated by the osteoinductive growth factor BMP-3. In that way metallic implants can achieve osteogenic properties which have positive effects in osseointegration.

Alloys↗
PubMedDate not supplied

[Fundamental aspects of osteoinductive activity of bone tissue and potential clinical application].

Osteoinductive polypeptide factors such as the various isoforms of Bone Morphogenetic Protein described are of increasing scientific and clinical interest because of the great progress in this field of skeletal biology recently achieved. In a review some fundamental chemical and biological aspects of bone and its endogenous osteoinductive activity including isolation and assay of osteoinductive factors are described. Through combination of osteoinductive factors with appropriate carrier materials it seems possible to create osteoinductive implant materials and the results of such investigations and some basic aspects of carrier materials are summarized. The perspectives of the possible clinical applications of such composite are presented.

Biocompatible Materials↗
PubMedDate not supplied

[Suppression of heterotopic ossification: single-dose versus fractionated irradiation--animal study].

Periarticular ossification is one of the main problems of total hip replacement. Irradiation with megavolt photons is known to be a well recognized means of prevention of heterotopic ossification. So far only little scientific basis exists about the most favourable way of radiotherapy for prevention of ectopic ossification. In this study two theoretically equivalent doses are compared. Allogeneic bone matrix was implanted into both thighs of 50 adult male Wistar rats for experimental induction of heterotopic ossification. Immediately after operation the thigh implants were irradiated with a single dose of 7 Gy or a total dose of 10 Gy given in 5 fractions of 2 Gy each. In the model of matrix-induced osteogenesis in rats fractionated irradiation by 5 x 2 Gy leaded to a highly-significant (p = 0.001) better suppression of ectopic ossification compared to irradiation by 1 x 7 Gy. Once-only irradiation with 1 x 7 Gy leads to a reduction of the calcium contents by 27.5%, split irradiation by 5 x 2 Gy obtained a reduction by 66.9% compared to the calcium contents of thigh implants not exposed to radiation. In view of experimentally proven better effects, fractionated irradiation has to be preferred to single dose radiation also considering less side effects in split radiation.

Animals↗
PubMedDate not supplied

[Histologic and histomorphometric follow-up observations of osseointegration of corundum-blasted BMP-3 coated titanium test implants (Ti6Al4V) at orthotopic site in the giant rabbit].

AIM: To establish whether the additional coating of titanium implants with Bone Morphogenetic Protein-3 (BMP-3) might enhance osseous integration. METHOD: Each of 15 cylindrical titanium test implants (Ti-6AI-4V) was coated using 230 micrograms porcine BMP-3. A further 15 implants with identical (corundium-blasted) surface served as negative controls. An uncoated and a BMP-3-coated test object were implanted into the femurs of 15 adult giant rabbits. New formation of bone around the implants was examined microscopically and histomorphometrically on postoperative days 14, 35 and 56. RESULTS: Coated implants revealed superior osseointegration with statistical evaluation using the t-test for matched samples showing a significantly higher volume of new bone 5 weeks after surgery. Microscopic examination revealed osseointegration with no connective tissue membrane around the surface of the implants. CONCLUSIONS: Our results indicate that composite metal implants are suitable carriers for BMP-3 and that improved fixation of the implants can be achieved.

Alloys↗