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A Gropper

Publications and source records attributed to A Gropper.

4 recordsLinked to original sources
PubMed1998

Enterprise-scale image distribution with a Web PACS.

The integration of images with existing and new health care information systems poses a number of challenges in a multi-facility network: image distribution to clinicians; making DICOM image headers consistent across information systems; and integration of teleradiology into PACS. A novel, Web-based enterprise PACS architecture introduced at Massachusetts General Hospital provides a solution. Four AMICAS Web/Intranet Image Servers were installed as the default DICOM destination of 10 digital modalities. A fifth AMICAS receives teleradiology studies via the Internet. Each AMICAS includes: a Java-based interface to the IDXrad radiology information system (RIS), a DICOM autorouter to tape-library archives and to the Agfa PACS, a wavelet image compressor/decompressor that preserves compatibility with DICOM workstations, a Web server to distribute images throughout the enterprise, and an extensible interface which permits links between other HIS and AMICAS. Using wavelet compression and Internet standards as its native formats, AMICAS creates a bridge to the DICOM networks of remote imaging centers via the Internet. This teleradiology capability is integrated into the DICOM network and the PACS thereby eliminating the need for special teleradiology workstations. AMICAS has been installed at MGH since March of 1997. During that time, it has been a reliable component of the evolving digital image distribution system. As a result, the recently renovated neurosurgical ICU will be filmless and use only AMICAS workstations for mission-critical patient care.

Computer Communication Networks↗
PubMed1994

Fentanyl or alfentanil decreases the minimum alveolar anesthetic concentration of isoflurane in surgical patients.

The minimum alveolar anesthetic concentration (MAC) is an accepted potency measure for inhaled anesthetics. There is no generally accepted intraoperative measure of opioid potency, partly because of the difficulty in obtaining steady state biophase concentrations. We have studied the relative potency of fentanyl and alfentanil by using computer-assisted continuous infusions (CACI), in terms of reduction of isoflurane MAC. Data are presented from 79 patients in whom anesthesia was induced with thiopental and maintained with a CACI of fentanyl (set to achieve a plasma concentration of 0, 1, 3, 6, or 8 ng/mL) or alfentanil (0, 70, 210, 400, or 1000 ng/mL) with a predetermined end-tidal concentration of isoflurane. A determination of movement in response to skin incision was made. Without any opioid, the MAC of isoflurane was 1.25%. The maximum likelihood solution to a logistic regression model showed that fentanyl 0.5 ng/mL (95% confidence intervals [CI], 0-4.6 ng/mL) or alfentanil 28.8 ng/mL (95% CI, 0-70.9 ng/mL) resulted in a 50% isoflurane MAC reduction. In the logistic regression model, age or weight were not significant factors in the model. These results suggest that the comparative intraoperative potency ratio for alfentanil and fentanyl is 58:1, and that this methodology allows for direct intraoperative comparisons of opioid potency.

Adult↗