Biomedical subjects

P Kessler

Publications and source records attributed to P Kessler.

At least 73 records · Page 4Linked to original sources

PubMed2000

Occupational exposure to nitrous oxide and desflurane during ear-nose-throat-surgery.

PURPOSE: To determine occupational exposure of the anesthesiologist and surgeon to nitrous oxide and desflurane during general anesthesia for ear-nose-throat (ENT) surgery in children and adults. METHODS: An observational clinical trial was performed in ten children (C) and ten adults (A). Tracheas were intubated, in adults, with cuffed tubes and in children with uncuffed tubes. The operating room was equipped with modern air conditioning and waste anesthetic gas scavengers. Gas samples were obtained during the operative procedure every 90 sec from the breathing zone of subjects. Time-weighted averages (TWA) over the time of exposure were calculated for nitrous oxide and desflurane. RESULTS: Nitrous oxide TWAs for anesthesiologists were 0.41 +/- 0.23 ppm (A) and 1.20 +/- 0.32 ppm (C, P < 0.0001), and 2.24 +/- 1.93 ppm (A) and 5.30 +/- 0.60 ppm (C, P = 0.0001) for the surgeon who worked close to the patient's airway and thus had higher exposure (P < 0.05 [A], P < 0.0001 [C]). With regard to desflurane, the anesthesiologists' TWAs were 0.02 +/- 0.03 ppm for both adults and children. The surgeon was exposed to 0.21 +/- 0.24 ppm desflurane (A) and 0.30 +/- 0.14 ppm (C, P: n.s.). Although the surgeon's exposure was greater (P < 0.05 [A], P < 0.0001 [C]), the threshold limits of 25 ppm for nitrous oxide and 2 ppm for desflurane recommended by the National Institute of Occupational Safety and Health were not exceeded. CONCLUSIONS: Under modern air conditioning, occupational exposure to inhalational anesthetics is low, and inhalational anesthesia is safe from the standpoint of modern workplace laws and health-care regulations.

Adult↗

PubMed2000

[Special anesthesiologic features in minimally invasive heart surgery].

When heart-lung machines made extracorporeal circulation possible in the fifties, cardiac surgeons gained virtually unrestricted access to the resting, motionless heart. Valve repair and reconstruction, in particular, made great progress as a result of extracorporeal circulation. While the distinct advantages of extracorporeal circulation for cardiosurgery remain undisputed, awareness of the significant perioperative risks of extracorporeal circulation for the patient has been increasing in recent years. This has lead to an interest in alternative cardiosurgical techniques avoiding extracorporeal circulation. Inspired by minimally-invasive procedures in abdominal surgery, cardiosurgical instruments as well as surgical techniques of access to the heart and large thoracic vessels were systematically modified leading to today's minimally-invasive cardiosurgical procedures such as off-pump coronary artery bypass grafting on the beating heart. Similarly, in the field of cardiac valve repair, new cannulation techniques for instituting extracorporeal circulation make median sternotomy unnecessary. The developments described above have lead to the recent introduction of robot-assisted techniques with or without extracorporeal circulation, which are expected to make possible in the near future the performance of the whole range of cardiosurgical procedures with minimal surgical trauma. The introduction of the new techniques has changed the intraoperative responsibilities of the anesthesiologist. The present article will therefore describe both the new surgical techniques as well as the new tasks required of the anesthesiologist, in particular with regard to cannulation and monitoring. Since a number of terms in minimally-invasive cardiosurgery are not precisely defined, a clear description of the various surgical techniques is also provided.

Anesthesia↗

PubMed2000

[Aids and anesthesia] .

17 years after the discovery of HIV Aids remains an ultimately fatal disease. Currently no vaccine is available. The worldwide incidence of HIV-infections and Aids associated mortality are rising. Only in Western Europe and in the USA are incidence and mortality of Aids declining; mainly as a result of effective antiretroviral therapy. 20% to 25% of HIV-infected patients require surgery during their illness. The challenges for the anaesthesiologist are possible dysfunction of all important organs and adverse interactions between antiretroviral drugs and anaesthetic agents. If adequate infection control measures are taken the risk of occupational HIV-infection is low, but remains a concern in light of the consequences. Seroconversion after needlestick injury is ca. 0.3%, after contact with mucosa ca. 0.03%.

Acquired Immunodeficiency Syndrome↗

PubMed2000

[Remifentanil-propofol for bronchoscopic fiber optic intubation under capnographic control].

UNLABELLED: We report a case of a 41-years-old woman presenting for revision of a secondary reconstructive procedure using the modified Tagliacozzi upper arm flap after subtotal maxillectomy. Because of the pedicle flap the upper arm was fixed in a pre-facial position and so fiberoptic intubation was required. After routine pre-anesthetic preparations and topical anesthesia of the nares and nasopharynx a CO2 measuring catheter as well as a O2 catheter to administer 100% oxygen was inserted deeply into the left naris. At that time, a continuous infusion of 0.05 microgram/kg/min remifentanil and 2 mg/kg/h propofol was started. After 4 min, fiberoptic intubation was performed through the right nare without any technical difficulties in conscious sedation of the patient. During the entire fiberoptic intubation SaO2 was constant at 100% and capnogram tracings with etCO2 values ranging from 31 to 33 mmHg were displayed on the monitor. At the end of this second surgical procedure with fixed pre-facial upper arm position the patient was uneventfully extubated fully awake. For the time period of fiberoptic intubation the patient had complete amnesia. CONCLUSION: With the use of nasal capnography and capnometry in addition to simultaneous O2 administration during fiberoptic intubation under extreme conditions excellent analgosedation with propofol and remifentanil could be provided without compromising our patients' safety. The presented CO2 measuring and O2 administering device represents a simple and cheap expansion of standard anesthetic monitoring during fiberoptic intubation.

Adult↗

PubMed2000

[Possibilities of computer graphics simulation in orthopedic surgery].

BACKGROUND: In addition to standard X-rays, photographic documentation, cephalometric and model analysis, a computer-aided, three-dimensional (3D) simulation system has been developed in close cooperation with the Institute of Communications of the Friedrich-Alexander-Universität Erlangen-Nürnberg. With this simulation system a photorealistic prediction of the expected soft tissue changes can be made. Prerequisites are a 3D reconstruction of the facial skeleton and a 3D laser scan of the face. After data reduction, the two data sets can be matched. Cutting planes enable the transposition of bony segments. The laser scan of the facial surface is combined with the underlying bone via a five-layered soft tissue model to convert bone movements on the soft tissue cover realistically. CONCLUSION: Further research is necessary to replace the virtual subcutaneous soft tissue model by correct, topographic tissue anatomy.

Cephalometry↗

PubMed2000

[Continuous bone distraction with the help of a microhydraulic cylinder].

Distraction osteogenesis of the mandible is one treatment option in mandibular hypoplasia. Usually, a non-continuous distraction mode is applied. The aim of the present study was to establish continuous bone distraction using a microhydraulic cylinder. Using a submandibular approach, the mandible was dissected subperiostally on one side in four mini-pigs; corticotomy was performed and the microhydraulic cylinder fixed with two bicortical screws. The hydraulic tube was connected with an automatic hydropneumatic injector system. Following 7 days at rest, a continuous distraction of 1.5 mm per day was performed for 14 days. After 2 and 4 weeks postoperatively, the animals were killed and X-rays taken. The mandible was then removed en bloc and microscopic evaluation of the sections was performed. The microhydraulic cylinder was easy to apply and to handle. The continuous stimulus did induce direct mineralisation of longitudinal oriented collagenous fibre bundles. Bony regeneration seems to be accelerated, which might reduce the postoperatively stabilizing phase.

Animals↗

PubMed2000

[Distraction osteogenesis of the mandible in craniofacial abnormalities].

In recent years, lengthening the human mandible by distraction osteogenesis has become an accepted treatment to correct severe mandibular hypoplasia. Using intraoral unidirectional and extraoral bidirectional distraction devices we report about our experiences and results in the application of the bone distraction technique in four selected cases of syndromal disease, including various forms of mandibular hypoplastic malformations. The patients involved were a boy with Pierre Robin syndrome, a girl with unilateral facial hypoplasia in Goldenhar's syndrome, a case with Nager's syndrome, and a rare case of midline deficiency caused by partial deletion of chromosome 18 (18p-syndrome). The distraction period lasted from 6 to 30 days and new bone formation, ranging from 6 to 28 mm, was achieved.

Adolescent↗

PubMed2000

Endoscopic and ultrasonographic evaluation of the maxillary sinus after combined sinus floor augmentation and implant insertion.

OBJECTIVE: The aim of our study was a radiographic, endoscopic, and ultrasound follow-up of the maxillary sinus comparing 2 techniques of sinus floor augmentation. STUDY DESIGN: Sonograms, radiographs (Waters' view) of the sinuses, and endoscopy served before and during surgery to evaluate the maxillary sinus. One week after the operation, ultrasound and radiograph follow-up (Waters' view) were carried out. Six months after the operation, we performed an ultrasound follow-up along with uncovering the implants. If any pathologic condition was found, we took another x-ray film of the sinuses, performed another endoscopic examination, or both. RESULTS: In 23 of 63 patients, healing was uneventful. Waters' view revealed opacification of the maxillary sinus 1 week after surgery in 40 cases when the "window technique" was used. Sinusitis occurred 3 times, as a result of migration of bone chips in 2 patients. We lost 11 of 132 inserted implants during the healing and loading periods. CONCLUSION: Endoscope-controlled sinus floor augmentation may lower the complication rate in a remaining height of the jaws between 4 and 8 mm. In our group of patients, we proved by endoscopic examination that migration of cancellous bone sequestra was the reason for sinusitis. In case of infected bone grafts with antral symptoms, sinoscopy allowed debridement and removal of a sequestrum.

Alveolar Ridge Augmentation↗

PubMed2000

A new distraction device to compare continuous and discontinuous bone distraction in mini-pigs: a preliminary report.

Callus-distraction has become an accepted procedure to lengthen hypoplastic mandibles in humans. Extra- and intraoral devices have been applied successfully. Systematic studies have proven the importance of direction, stability, rate and frequency in callus-distraction. In an experimental animal study a newly developed intraoral microhydraulic osteodistractor was tested. Initially the pressures necessary to distract the mandible in mini-pigs were recorded in discontinuous callus-distraction. These results were used to perform continuous bone distraction. Besides testing the new distractor and evaluating the distraction pressures, the aim of the study was to prove that direct bone growth occurred without preceding cartilage formation. Clinical and microscopic results are presented.

Animals↗

PubMed2000

Biodegradable miniplates (LactoSorb): long-term results in infant minipigs and clinical results.

Metallic plates are known for their passive intraosseous transmission in the growing skull. To avoid plate removal, resorbable material with strength comparable to that of metallic plates and predictable resorption would be desirable. This should be accomplished without causing inflammatory complications and foreign body reactions often seen with highly crystalline poly-L-lactic acid or pure polyglycolic acid implants. In an animal experiment in four young Göttingen minipigs, the resorbable poly-L-lactic acid/polyglycolic acid copolymer LactoSorb was tested previously. In addition to testing the mechanical properties, the process of degradation and sub- versus epi- or supraperiosteal application of the miniplate device LactoSorb was evaluated using a frontal cranioosteoplasty model. Furthermore, LactoSorb was used in 10 patients with craniosynostosis or craniofacial trauma. During degradation, the absorbable poly-L-lactic acid/polyglycolic acid miniplates acted like metal plates because they also displayed passive intraosseous transmission in the growing animal model. Degradation took 12 to 18 months and was not delayed by bony incorporation. Their mechanical properties proved to be sufficient in craniofacial surgery. Epiperiosteal plating prolonged the passive intraosseous transmission effect during the first 3 months after surgery. There were no major inflammatory reactions seen in the experimental and/or in the clinical study.

Absorbable Implants↗

PubMed1999

Proinflammatory mediators chronically downregulate the formation of the endothelium-derived hyperpolarizing factor in arteries via a nitric oxide/cyclic GMP-dependent mechanism.

BACKGROUND: Endothelium-dependent dilator responses mediated by NO and endothelium-derived hyperpolarizing factor (EDHF) are altered in arteriosclerosis and sepsis. The possibility that proinflammatory mediators that stimulate the expression of inducible NO synthase (NOS II) affect the generation of EDHF was examined in isolated arteries. METHODS AND RESULTS: Under combined blockade of NOS and cyclooxygenase, EDHF-mediated relaxation elicited by several agonists was significantly attenuated in rabbit carotid and porcine coronary arteries exposed to cytokines and lipopolysaccharide. The blunted relaxation was coincident with NOS II expression and was prevented by inhibition of NOS II as well as of global protein synthesis. The NO donor CAS 1609 and 8-bromo-cGMP mimicked the proinflammatory mediator effect. In contrast, long-term blockade of endothelial NO generation increased the relaxation in carotid but not in coronary arteries. Proinflammatory mediators reduced the synthesis of EDHF assessed as hyperpolarization of vascular smooth muscle cells elicited by the effluent from bradykinin-stimulated coronary arteries. Proinflammatory mediators induced NOS II expression in cultured endothelial cells and decreased the expression of cytochrome P450 enzymes, which are the most probable candidates for the synthesis of EDHF. CONCLUSIONS: Proinflammatory mediators inhibit the formation of EDHF in isolated arteries. This impairment is coincident with NOS II expression in the arterial wall and seems to be mediated through the induced generation of NO, which downregulates the putative EDHF-forming enzyme. Thus, a decreased formation of EDHF may contribute to the endothelial dysfunction in arteriosclerosis and sepsis.

Animals↗

PubMed1999

Patient selection for Port-Access multi vessel revascularization.

Minimally invasive multivessel revascularization is rarely performed due to the difficult exposure of the aorta as well as the complete coronary anatomy through a small thoracotomy. The Port-Access technique bears additional contraindications for this procedure, which limits its potential as compared with other approaches to 'less invasive surgery'. Our aim was to show the applicability of this surgical technique to a wide range of patients with coronary artery disease. In our initial experience with this method (31 patients), the quality of anastomoses, graft patency, and clinical outcome are good, and do not differ from standard multivessel coronary artery bypass grafting. Port-Access multivessel revascularization can be performed safely and is appropriate for a large patient population.

Cardiac Catheterization↗

PubMed1999

[Infection or SIRS--the problem of definition].

Despite the knowledge about sepsis for many years, the definition of sepsis is contested more than ever since the early 90th. Therefore, the comparability of many clinical investigations and scientific work in the past is still impaired. To define the entrance criteria for further clinical studies, in 1991 a consensus conference was held in the USA, but its recommendations have not found unequivocal acceptance. Therefore, these recommendations are presented and their meaning will be discussed.

Diagnosis, Differential↗

PubMed1999

[Drug interactions in coumarin anticoagulation].

The clinically most important negative properties of coumarin anticoagulants are their numerous interactions with other drugs. Data in the literature on these interactions are frequently controversial. The causes of this phenomenon are a) the complicated path from ingestion of anticoagulants to their clinical effect and laboratory results, b) interindividual differences in enzyme activity participating in vitamin K metabolism, in the synthesis of hemocoagulation factors and in the biotransformation of coumarin derivatives, c) the different clinical state of the patient on the one hand and the healthy volunteer on the other, d) differences in the biotransformation of different coumarin derivatives and their optic isomers. In the submitted paper the authors describe pharmacokinetic and pharmacodynamic mechanisms of drug interactions of coumarin anticoagulants and their importance for clinical practice. In the conclusion recommendations are submitted to reduce the risk of these interactions.

Anticoagulants↗

PubMed1998

Targeted disruption of the acid alpha-glucosidase gene in mice causes an illness with critical features of both infantile and adult human glycogen storage disease type II.

We have used gene targeting to create a mouse model of glycogen storage disease type II, a disease in which distinct clinical phenotypes present at different ages. As in the severe human infantile disease (Pompe Syndrome), mice homozygous for disruption of the acid alpha-glucosidase gene (6(neo)/6(neo)) lack enzyme activity and begin to accumulate glycogen in cardiac and skeletal muscle lysosomes by 3 weeks of age, with a progressive increase thereafter. By 3.5 weeks of age, these mice have markedly reduced mobility and strength. They grow normally, however, reach adulthood, remain fertile, and, as in the human adult disease, older mice accumulate glycogen in the diaphragm. By 8-9 months of age animals develop obvious muscle wasting and a weak, waddling gait. This model, therefore, recapitulates critical features of both the infantile and the adult forms of the disease at a pace suitable for the evaluation of enzyme or gene replacement. In contrast, in a second model, mutant mice with deletion of exon 6 (Delta6/Delta6), like the recently published acid alpha-glucosidase knockout with disruption of exon 13 (Bijvoet, A. G., van de Kamp, E. H., Kroos, M., Ding, J. H., Yang, B. Z., Visser, P., Bakker, C. E., Verbeet, M. P., Oostra, B. A., Reuser, A. J. J., and van der Ploeg, A. T. (1998) Hum. Mol. Genet. 7, 53-62), have unimpaired strength and mobility (up to 6.5 months of age) despite indistinguishable biochemical and pathological changes. The genetic background of the mouse strains appears to contribute to the differences among the three models.

Alleles↗

PubMed1998

[Results of transcranial and subcranial management of fractures of the naso-ethmoid-orbital system in complex midfacial fractures].

Injuries of the nasoethmoid-orbital (NEO) region are associated with midfacial fractures or fractures of the frontobase in over 90% of all cases. In up to 70% fractures of the skull base run through the roof of the ethmoidal bone or the lamina cribrosa. There are different surgical approaches for the treatment of these complex fractures. Between 1990 and 1997 50 patients with midfacial fractures in association with NEO fractures were treated in the Klinik für Mund-, Kiefer- und Gesichtschirurgie, Kantonsspital Luzern, Switzerland. Of these, 25 had suffered midfacial fractures combined with fractures of the nasoethmoid-orbital and frontobasal region and were treated via a transcranial approach. The other 25 patients with midfacial and NEO fractures without involvement of the frontobasis were managed by subcranial incisions. A total of 47 patients were followed up for up to 4 years. The results were reevaluated retrospectively. There was no case of secondary liquorrhea, intracranial or ethmoidal infection. Our therapeutic concept of transcranial and subcranial management of NEO fractures in combination with frontobasal and midfacial fractures is demonstrated.

Adolescent↗

PubMed1998

Nitric oxide inhalation in acute pulmonary hypertension after cardiac surgery reduces oxygen concentration and improves mechanical ventilation but not mortality.

Impaired right-ventricular function may benefit from afterload reduction. Inhalation of nitric oxide (NO) reduces pulmonary hypertension without systemic circulatory depression. Influence of NO inhalation on oxygenation, ventilation, and hemodynamic parameters in 10 patients with acute pulmonary hypertension after cardiac surgery was examined in this study. Ten patients without NO treatment served as a control group. NO patients showed significantly improved oxygenation and recovery of right-ventricular function. Pulmonary artery pressure (12.8%), inspiratory oxygen demand (34.7%), PEEP (13.2%), and inspiration time (18.8%) decreased significantly during inhalation of nitric oxide. Mortality in both groups was identical. We therefore conclude that NO, by improving oxygenation and right-ventricular function, temporarily reduces invasiveness of mechanical ventilation. Reduction of invasiveness of ventilation did not influence mortality as compared with patients who did not receive NO. To finally estimate the benefit of NO inhalation, larger patient groups need to be examined.

Administration, Inhalation↗

PubMed1998

[Methicillin-reistant Staphylococcus aureus: risk factors for infection-colonization and clonal heterogeneity in intensive care units].

PURPOSE: The aim of this study was to determine the risk factors associated with colonisation/infection by methicillin-resistant Staphylococcus aureus (MRSA) and to demonstrate the chain of infections by genotyping of all MRSA isolates. METHODS: A total of 6143 microbiological samples from 1753 patients was obtained at a surgical ICU of Frankfurt University hospital during 1995. RESULTS: MRSA was detected in 1.6% of patients and three members of staff (3.3%). Typing of these 31 MRSA-strains (first isolates) by macrorestriction analysis of chromosomal DNA revealed nine different genotypes. More than 60% of all isolates belonged to one type that was confirmed to be closely related to the "South Germany" epidemic strain. A strong correlation between severity of underlying disease and length of hospitalisation on the one hand and detection of MRSA on the other could be demonstrated. Detection of MRSA was significantly more common in patients with adult respiratory distress syndrome (ARDS), sepsis, kidney failure, prolong respiratory treatment and in patients with prolonged phases of haemodynamic instability. It appeared that the mortality rate of MRSA-infected patients was higher (28.6%) than the mortality rate of all patients (6.5%). CONCLUSION: Following of a strict hygiene regime is important to prevent clonal spread of MRSA and especially to protect immunocompromised patients from complicating infections.

Adult↗