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Biomedical subjects

R Dwyer

Publications and source records attributed to R Dwyer.

35 records · Page 2Linked to original sources
PubMed1992

Isoflurane anesthesia prevents unconscious learning.

We investigated whether greater than or equal to 0.6 minimum alveolar concentration (MAC) of isoflurane suppresses learning of information presented verbally. Preoperatively, we asked 45 healthy patients (aged 23-58 yr) undergoing elective surgery 15 general knowledge questions designed to arouse their curiosity. They were told that they would be given the answers during anesthesia. Anesthesia was induced with isoflurane and nitrous oxide (25 subjects also received 1.1 +/- 0.6 mg/kg of propofol). The trachea was intubated with the aid of vecuronium (0.07 mg/kg IV). Isoflurane in oxygen was given to provide 0.6 MAC before and 1.0 and 1.4 MAC during surgery. After 10 min at each of two of the three MAC levels, the answers were given to five of the questions. At the remaining concentration, patients received a message to either touch an ear (n = 30) or keep their arms still (n = 15) during the postoperative interview. Twenty-four hours later, patients were asked whether they recalled intraoperative events. They were then asked to answer the 15 questions, choosing from five possible answers to each, one of which was correct. The number of times each patient touched an ear during this interview was noted. No patient consciously recalled events during anesthesia. The number of questions answered correctly postoperatively did not differ according to whether the answers had been provided during anesthesia (at any isoflurane concentration) or had not been provided (control questions). The number of ear-touches postoperatively did not differ between those who had and had not received the intraoperative message encouraging ear-touching.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Visceral losses of desflurane, isoflurane, and halothane in swine.

Percutaneous loss of inhaled anesthetics is small relative to their uptake. The minor nature of this loss results in part from the substantial barrier to diffusion posed by the skin. Pleural and peritoneal surfaces pose less effective barriers because diffusion distances are smaller than in the skin. Accordingly, we measured visceral loss to air of desflurane, isoflurane, and halothane from pleural and peritoneal surfaces in five juvenile swine. Pleural and peritoneal losses per percent end-tidal anesthetic correlated directly with the solubility of the anesthetic in blood or tissues. The total pleural losses for the first 30 min of anesthetic administration were desflurane, 1.22 +/- 0.22 mL (mean +/- standard deviation for the 30-min period); isoflurane, 2.34 +/- 0.52 mL; and halothane, 4.69 +/- 0.98 mL; respective peritoneal losses were 0.64 +/- 0.12 mL, 1.23 +/- 0.25 mL, and 2.69 +/- 0.57 mL. Pleural loss per unit time did not change with increasing duration of anesthesia, whereas peritoneal loss increased for all anesthetics. These visceral losses are greater than total percutaneous losses in humans given these anesthetics for the same period of time, but the loss of anesthetic by either route is too small to affect measurements of anesthetic kinetics or recovery.

Administration, Inhalation↗
PubMed1990

End-tidal concentrations of halothane and isoflurane during induction of anaesthesia in young and elderly patients.

Twenty-two young (18-32 yr) and 22 healthy elderly (60-80 yr) patients received either halothane or isoflurane for maintenance of anaesthesia during controlled ventilation. End-tidal fractional concentrations (FE) of the agents were measured for 20 min after their introduction into inspired gas and the increase in end-tidal concentrations of the two agents was compared during induction of anaesthesia using the ratios of FE to the inspired fraction (FI). FE:FI ratios for isoflurane were higher than those for halothane in both young and elderly patients, confirming that equilibration of end-tidal with inspired concentration occurs more rapidly with isoflurane than with halothane in both age groups. FE:FI ratios for isoflurane became significantly lower in the elderly than in the young after 15 min administration of isoflurane. This suggests slower induction of anaesthesia in the elderly if equipotent concentrations of isoflurane are used; the clinical significance of this difference is probably small. Mean FE:FI ratios for halothane in elderly patients were similar to those in the young throughout induction of anaesthesia.

Adolescent↗
PubMed1989

A vasculopathy with deposition of lambda light chain crystals.

An 82-year-old man and a 34-year-old woman developed subacute, obstructive, fatal vasculopathies characterized by extensive crystalline tissue deposits and monoclonal lambda light chain serum components. Cryocrystalglobulinemia was also present in one patient, and the purified crystals contained only lambda light chain dimers. Although the presentation of these patients resembled that of systemic necrotizing vasculitis, histologic evidence of inflammation was lacking and their subsequent rapid clinical deterioration was not altered by corticosteroid therapy, and in one case cyclophosphamide and plasmapheresis. Both patients died within 3 weeks of presentation.

Adult↗
PubMed1988

Comparison of propofol and methohexitone as anaesthetic agents for electroconvulsive therapy.

Propofol was compared to methohexitone for induction of anaesthesia for electroconvulsive therapy. Seizures were significantly shorter after the use of propofol, in respect of both visible seizures and duration of cerebral electrical seizure activity. This suggests the possibility that additional treatments may be needed for the same clinical effect in psychiatric illness when propofol is used as the induction agent. Propofol was more effective than methohexitone at obtunding the hypertensive response to electroconvulsive therapy without causing significant hypotension.

Adult↗
PubMed1986

Laser welding: an alternative method of venous repair.

This study compared the histology, biochemistry, tensile strength, and extensibility of Nd:YAG laser-welded and sutured venotomies. Two-centimeter-length bilateral canine femoral or jugular venotomies were evaluated with one vessel (control) closed with interrupted 6-0 polypropylene sutures, and the contralateral vessel (experimental) welded with the Nd:YAG laser (1 W power and 30- to 40-sec exposure). Specimens were removed and examined immediately after fashioning (t0) and at 1, 4, or 5 weeks post-operatively to compare the progression of healing. Histologic examination of the 4- and 5-week sutured wounds had granulomatous reaction around the sutures with areas of excessive collagen accumulation. In contrast, the laser-welded wounds had minimal inflammatory response, near normal collagen content, and minimal residual disorientation and break in the elastic fiber continuity. The rate of collagen synthesis in laser-welded wounds was approximately twice that of sutured wounds at 1, 4, and 5 weeks, and correlated with increased tensile strengths of lasered wounds. The extensibility of the 5-week specimens was 0.19 for sutured and 0.29 for laser-welded wounds as compared to 0.29 for normal vein. These preliminary data suggest that laser welding of venotomies may have several advantages over conventional suture techniques.

Animals↗
PubMed1978

Gastric candidiasis.

Two cases of candidiasis occured in the stomach. The first is a case of disseminated candidiasis with stomach wall involvement. The patient had Hodgkin's disease and responded to chemotherapy and amphotericin B. The second is a case of superficial invasion of Candida in a stitch ulcer. Systemic and local factors influence growth of Candida in the stomach.

Aged↗
PubMedDate not supplied

Nurse practitioners: an evaluation of the extended role of nurses at the Kirketon Road Centre in Sydney, Australia.

The aim of the present study was to formally evaluate the effectiveness, professional appropriateness and acceptability of the extended role of the nurse practitioner at the Kirketon Road Centre (KRC) in Sydney, Australia. Data collection consisted of client and staff surveys and case file review by two assessors (one medical and one nursing). This paper will report on one section of this research, namely the case file review section of the study. Total study subjects were 1046 'at risk' youth, sex workers and injecting drug users attending KRC for their primary health care needs between September 1994 and April 1995. Nurse practitioners (NP) saw 613 of the clients who presented over this period. The majority of these clients were women (77.3%). The majority of NP consults were related to STD (51%), gynaecological (17%) and hepatitis (16%) issues. The results demonstrated that nurse practitioners were professionally appropriate in all aspects of expected 'best practice' in over 95% of consultations.

Adolescent↗
PubMedDate not supplied

Benchmarking outcome in ICU.

There are as yet few well developed systems for comparing the quality of care in Irish hospitals with other hospitals either nationally or internationally. The best known are the perinatal mortality rates of the Dublin maternity hospitals. Other examples include mortality rates after cardiac surgery and survival rates after cancer surgery. We describe a comparison of outcomes in an Irish ICU with internationally validated mortality rates for a given severity of illness. The method of stratifying for severity of illness is by use of the APACHE II scoring system. In 2003 the standardised mortality ratio for Beaumont Hospital ICU was 0.87 with a mean APACHE II admission score of 17.5 which compares favourably with similar data produced from UK units.

APACHE↗