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Biomedical subjects

I Baumgartner

Publications and source records attributed to I Baumgartner.

100 records · Page 6Linked to original sources

Ultrasound biomicroscopy of tangential keratotomy incision depth after penetrating keratoplasty.

PURPOSE: To assess the accuracy and reproducibility of using ultrasound biomicroscopy to measure corneal refractive incisions in vivo. SETTINGS: Department of Ophthalmology, University of Vienna, Austria. METHODS: Ultrasound biomicroscopy was performed in five eyes of five patients who had previous tangential keratotomy for high postkeratoplasty astigmatism. Depth of the incision scar was documented, and the measurements were compared with those obtained preoperatively by ultrasound pachymetry readings of the corneal thickness and with the settings of the diamond knife blade. RESULTS: The measured depths reached 84.7% +/- 12.9 (SD) of corneal thickness compared with the intended 89.1 +/- 6.7% depth of incision. The relation between knife setting and achieved depth was 95.3 +/- 15.9%. CONCLUSION: Ultrasound biomicroscopy provided high-quality images of the incision scars, accurately measuring actual incision depth in vivo. It may become a clinically useful tool for the refractive surgeon as it contributes to the predictability and accuracy of keratorefractive procedures.

Astigmatism↗

Efficacy of norfloxacin in bacterial conjunctivitis.

We investigated the efficacy and safety of norfloxacin 0.3% ophthalmic solution in 120 patients with bacterial conjunctivitis or blepharitis. Patients were selected for the study if they showed conjunctival hyperemia and at least three of the following criteria: a) symptoms of a surface ocular infection; b) a purulent discharge; c) crusting of the eyelids, and d) thickened, red lid margins. After taking a specimen for culture from the conjunctiva or skin-lash margin, the test drug was administered to the infected eye every two hours for one day, then 4 times daily for one week. Of the 120 patients who entered the study, 84.1% were cured. No serious adverse reactions occurred.

Adolescent↗

Corneal lathing using the excimer laser and a computer-controlled positioning system.

PURPOSE: To present the excimer laser corneal shaping system (ELCS-S), an add-on device to the Keratom, a commercially available 193-nm excimer laser built by Schwind. METHODS: The system is designed for the preparation of donor corneas under sterile conditions using the ultraviolet laser to offer greatest possible flexibility. Lenticules for planolamellar grafting and refractive epikeratoplasty, as well as donor buttons for penetrating keratoplasty can be computer-designed by the surgeon or technician and lathed with the system. RESULTS: Using the excimer laser corneal shaping system (ELCS-S) on human donor corneas, the central surface of the epikeratoplasty lenticule exhibited only narrow, flat concentric notches corresponding to the single lathing steps. Transmission electron microscopy revealed a damage zone of less than 0.3 microm in close approximation to the treated surface. The final thickness revealed a difference of less than +/-53 microm from the intended, initially programmed value. Ultrastructural studies showed the perpendicular stromal surface of the penetrating keratoplasty buttons to be smooth with minimal protrusion of Descemet's membrane. Endothelial injury was observed in a zone averaging between 40 and 100 microm adjacent to the cutting edge only. CONCLUSION: The excimer laser corneal shaping system (ELCS-S) allows a computer-controlled, surgeon-designed, sterile preparation of lamellar and penetrating corneal grafts with the use of the excimer laser. This could offer significant advantages in comparison to presently available systems for lamellar dissection and trephination.

Computers↗

The use of di-hydroxypropylphenol (propophol) in endoscopic procedures.

The authors illustrate different endoscopic procedures that may require anaesthesiological assistance through analgo-sedation procedures. Analgo-sedation is useful to the patient and to the endoscopist that can carry out the exam more rapidly and in optimal conditions. The technique employed consists in the administration of propophol, starting with an initial bolus of the drug followed by a continuous perfusion to maintain the hypnotic state. Monitoring of cardiovascular and respiratory parameters shows a great reliability of the drug and effectiveness of the method.

Adolescent↗

Corneal lathing using the excimer laser and a computer-controlled positioning system: Part I--Lathing of epikeratoplasty lenticules.

Precise lathing of epikeratoplasty lenticules is difficult to achieve with the cryolathe due to unpredictable expansion of the lathing tools and the corneal tissue during the freezing process. In addition, the procedure destroys all viable cells in the transplant thereby possibly contributing to the prolonged period of visual rehabilitation. Non-freezing techniques using the microkeratome or the rotor-trephine, on the other hand, are technically demanding, can cause mechanical damage during cutting or fixation, and, have not given consistently reproducible refractive results. A new system is presented that allows a variable laser ablation of donor corneas into lenticules for aphakic and myopic epikeratoplasty, as well as for lamellar keratoplasty. With the help of a computer-controlled positioning system that uses high-precision micropositioning elements (both translation and rotational stages) the donor cornea is moved, epithelial side down, in a holding device in front of a focused excimer laser beam (ArF, lambda = 193 nm). This photoablation lathing process assures the viability of the stromal cells in the lenticule in close approximation to the treated surface. The user friendly computer software allows the fast and convenient selection of a variety of parameters, such as the diameter of the optical zone, the shape of the wing zone, the refractive power, the central thickness of the lenticule and the overall contour of the transplant. The first laboratory data of lenticules prepared from human corneas with this "Excimer Laser Corneal Shaping System" are presented.

Cornea↗

Corneal lathing using the excimer laser and a computer-controlled positioning system: Part II--Variable trephination of corneal buttons.

A new system is presented that allows a variable trephination of donor corneas for the preparation of corneal buttons used in penetrating keratoplasty. With the help of a computer-controlled positioning system that uses high-precision micropositioning elements (both translation and rotational stages) the donor cornea is removed, epithelial side up, in a fixation device in front of a focused excimer laser beam (ArF, lambda = 193 nm). User friendly computer software allows the surgeon to select a variety of parameters (diameter, shape, angle of trephination) of the corneal graft. Histological and electron microscopical data of human corneas trephined with this "Excimer Laser Corneal Shaping System" are presented.

Cornea↗

Variation of acid-base balance, glycemia, electrolytes and ETCO2 after fast i.v. infusion of 5% fructose and/or glucose.

Intraoperative fluid infusion has precise goals and the rapid infusion of some solutions can induce important modifications of homeostatic parameters, which must be known. Rapid infusion of fructose and glucose 5% solutions has been carried out and modifications of acid-base balance, glycemia, serum electrolytes, ETCO2 have been registered. The administration of fructose 5% determines a mixed acidosis while the administration of glucose does not cause this phenomenon; the administration of both carbohydrates reduces serum chloride and sodium, while serum potassium rises only after fructose infusion and glycemia only after glucose infusion. All the variations described reach significant levels.

Acid-Base Equilibrium↗

Analgesia and sedation with propofol-NSAIDs for day-hospital extracorporeal shock wave lithotripsy (ESWL).

After a brief history of extracoporeal therapies for calculosis, with particular attention devoluted to renal calculosis and to the instruments that consent these therapeutic alternatives, the authors report the results obtained with a technique of analgesia and sedation. The drugs employed are two NSAIDs, keto-prophene and ketorolac tromethamine associated with propofol. The main advantages consist in the limited cardiovascular and respiratory depression, typical of the first minutes of administration of propofol and the rapid return of a complete functional autonomy in relative brief time intervals, with possibility of dismissing the patient after 4 hours from che end of treatment.

Adult↗

Transcutaneous ethanol injection in hepatocarcinoma: problems in analgesia and sedation.

Therapeutic ethanol injection into primitive or secondary hepatic tumours if performed in "one shot" causes a great deal of pain. For this reason an analgesic/sedation protocol was devised. This relies on the administration of ketorolac-propofol-nitrogen oxide mixture that has been used to treat patients with neoplastic hepatic diseases. A 20 patient series is described. Analgesic protocol was very effective and the only drawbacks were a residual sleepiness than in part is probably dependent on ethanol emigration into the bloodstream and consequently to the central nervous system depression.

Aged↗