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Biomedical subjects

A Avidan

Publications and source records attributed to A Avidan.

12 recordsLinked to original sources

Attitudes of medical practitioners towards "Do Not Resuscitate" orders.

When the desires of a patient are unknown or cannot be ascertained, cardio-pulmonary resuscitation (CPR) is the default procedure. Explicit, Do Not Resuscitate (DNR), orders are required to prevent implementation of CPR. We studied the response of general medical internists in specific clinical situations demanding consideration of DNR orders and respect for patient preferences; their current practice regarding slow codes and participation in CPR attempts considered futile provide information as to how often they discuss DNR issues with patients or families. Eighty-five internists attending the monthly meeting of the Internal Medicine Forum participated in the study. The physicians demonstrated their consent to participate by accepting a remote transmitter that elicited a response 2-3 minutes following the presentation of case vignettes or practice-related questions. The survey showed that 73% of the physicians agreed to assign a DNR order for a terminally ill patient unable to express her preferences. Only 55% agreed to do the same for a competent patient who specifically requested that CPR be withheld in the event of a cardiopulmonary arrest (p<0.05). 77% reported to have performed CPR, at least three times, in situations where they expected no benefit. 59% affirmed that their team had performed a partial CPR (slow code) at least once. Only 28% discussed the subject of DNR with patients or family more than 5 times a year. Paternalism, disregard for patients' preferences and poor communication skills influence normative behaviour in end-of-life decision-making.

Case Reports↗

Medical aerosol propellant interference with infrared anaesthetic gas monitors.

BACKGROUND: 1,1,1,2 Tetrafluoroethane is a hydrofluoroalkane (HFA) that is replacing chlorofluorocarbons (CFC) as a medical aerosol propellant in an attempt to reduce damage to the ozone layer. This study compared the effects of HFA- and CFC-based inhalers on four anaesthetic gas monitoring systems. METHODS: The HFA- and CFC-based inhalers were activated in close proximity to the sample line of two Datex Ohmeda, an Agilent and a Siemens infrared anaesthetic agent monitoring systems. The effects were recorded on each system for five common anaesthetic agents. RESULTS: The HFA inhaler caused either maximal false positive readings (with the exception of desflurane) or transient measurement failure on all systems. The Datex Ohmeda AS/3 system misidentified the HFA inhaler as carbon dioxide at low concentration (2 +/- 0 mm Hg). The CFC-based inhaler caused a minor false-positive reading (0.4 +/- 0%) for halothane only on the Datex Ohmeda AS/3 system only and was misidentified as carbon dioxide at 33.3 (sd 2.1) mm x Hg and 22.4 (8.9) mm x Hg by the Agilent and Siemens systems. CONCLUSIONS: The HFA inhaler adversely affected all equipment tested. The infrared spectra of HFA and the common anaesthetic gases have considerable overlap at the 8-12 microm range that is not shared by the CFCs. The differences in spectral overlap explain the different effects of the HFA and CFC propellants. Anaesthetic gas concentration data may be erroneous using the HFA-based inhalers.

Aerosol Propellants↗

Cardiopulmonary bypass with two oxygenators.

We describe a technique to bypass a defective part of an oxygenator unit (venous reservoir or oxygenator part) by connecting a second oxygenator instead of replacing the whole oxygenator unit. If only the oxygenator part has to be replaced, further hemodilution can be avoided. This technique can be performed in very short time and is probably associated with less air embolism.

Aged↗

Antidiabetic action of vanadyl in rats independent of in vivo insulin-receptor kinase activity.

The effects of oral vanadyl sulfate administration for 9-12 days on carbohydrate and lipid metabolism in the basal state and on glucose dynamics during submaximal hyperinsulinemic clamps were investigated in nondiabetic and streptozocin-induced diabetic rats. Decreases in growth rate and water and food consumption were the only significant alterations noted in control animals receiving vanadyl. Administration of vanadyl to diabetic rats resulted in weight loss; a significant decrease in plasma glucose, triglyceride, and cholesterol levels; and decreases in food and water intake, without a concomitant change in plasma insulin concentrations. Vanadyl treatment did not modify either peripheral glucose utilization or hepatic glucose production in control rats during submaximal insulin clamps. In contrast, vanadyl therapy increased insulin-induced glucose utilization significantly and had a small but nonsignificant effect on insulin-mediated suppression of glucose production in diabetic rats. The tyrosine kinase activity of liver- and muscle-derived insulin receptors from diabetic rats that underwent clamp study, which reflected the in vivo phosphorylation state of insulin receptor, was not altered by vanadyl treatment. In conclusion, these results show that augmentation of peripheral glucose utilization is the major determinant of the antidiabetic action of vanadyl and support the notion that the action of vanadyl is independent of insulin-receptor kinase activity.

Animals↗

Medullary sites for TRH analogue stimulation of gastric contractility in the rat.

Medullary sites at which the stable thyrotropin-releasing hormone (TRH) analogue, RX 77368 (p-Glu-His-[3,3'-dimethyl]-Pro-NH2), stimulates gastric contractility were investigated in rats under urethan anesthesia. The peptide analogue was microinjected in 50-100 nl of volume unilaterally into various brain stem nuclei using glass micropipettes (50 microns). Gastric contractility was recorded continuously with acutely implanted strain-gauge force transducers and traces analyzed by computer. RX 77368 (2.6-77 pmol) microinjected into the dorsal vagal complex (DVC) dose dependently stimulated gastric contractility. Peptide action (77 pmol) had a rapid onset with a peak response at 15 min, continued for 45 min after the microinjection, and was blocked by vagotomy. TRH microinjected into the DVC had a shorter duration of action. RX 77368 (0.7-77 pmol) microinjected into the nucleus ambiguus also dose dependently stimulated gastric contractions. In contrast, microinjection of RX 77368 (77 pmol) into the hypoglossal nucleus had no effect. These findings demonstrate that the DVC and nucleus ambiguus are sites of action for TRH-induced stimulation of gastric contractility in the rat. The effect is dose dependent, long lasting, site specific, and vagally mediated. These results are consistent with a possible physiological role for medullary TRH in the vagal regulation of gastric contractility.

Animals↗