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Biomedical subjects

R Dwyer

Publications and source records attributed to R Dwyer.

At least 19 recordsLinked to original sources
PubMed2006

Addition of a macrolide to a ss-lactam in bacteremic pneumococcal pneumonia.

In the study presented here, data collected prospectively from 340 adult patients hospitalised in five countries with bacteremic pneumococcal CAP and treated with a ss-lactam +/- a macrolide were analysed retrospectively to evaluate the efficacy of this antimicrobial combination. Univariate and multivariate analyses revealed no significant effect on case fatality rate when a macrolide/ss-lactam regimen was used as initial therapy. Results were not affected by severity of illness, or by excluding patients who died within 2 days of admission. Identified predictors of death in a multivariate regression model were age >65 years (OR=2.6), two or more lung lobes affected (OR=2.2), and severity of disease as estimated using the acute physiology score (APS)>8.

Adult↗
PubMed2006

Audit of Mobile Intensive Care Ambulance Service.

The transfer of critically ill patients between hospitals carries significant risk. The Mobile Intensive Care Ambulance Service (MICAS) in Ireland was established in 1996 to provide a ground transfer service between hospitals for critically ill patients. The aim of this audit was to determine if a centralised retrieval system for interhospital transport of critically ill patients in Ireland by MICAS is safe and efficient. 484 critically ill patients transported by MICAS between April 1996 and December 2004 were studied retrospectively. There were no patient deaths during transfer. 47% of transfers were between hospitals in the greater Dublin area. 45% were from regional centres to Dublin. 93% of patients required airway intervention before transfer (intubation or tracheostomy) and 32% needed inotropic support during transfer. The MICAS data confirm the demand for interhospital transport of critically ill patients and suggest that transfer using a centralised retrieval system is safe.

Adolescent↗
PubMed2004

Brain death and organ donation: an audit in the Irish National Transplantation and Neurosurgical Centre.

We set out to identify the reasons why potential organ donors (PODs) fail to become actual donors and the causes of under-utilization of organs offered for donation. We audited 354 patients who died in the intensive Care Unit over 18 months. Of 155 PODs, 78 (50%) did not undergo brain stem testing (BST) because of (i) unavoidable death from non-CNS causes before BST (n = 50), (ii) treatment withdrawal without BST (n = 17) and (iii) preconditions for BST were not fulfilled (n = 11). Brain death was confirmed in 75 patients. Relatives refused consent for donation in 25 patients organ donation was not discussed with the family in 6, and medical contraindications to organ donation prevented donation in 5. Thirty seven (24% of all PODs) became organ donors who provided a total of 216 organ. All donated kidneys were utilized but unsuitability and logistic issues prevented utilization of 20% and 13% of all donated organs respectively. The commonest reason for failure to utilise potential organ donors was failure to perform BST. In most cases this was because BSTs were not possible but more aggressive management of and the routine performance of BST in all PODs could increase the number of donors. Not approaching relatives to ask consent for organ donation and a high rate of refusal by relatives also led to loss of organ donors.

Brain Death↗
PubMed2001

For love or money? An exploratory study of why injecting drug users participate in research.

AIMS: To examine injecting drug user (IDU) motivations as research participants. DESIGN: Convenience sampling facilitated by recruitment notices distributed through needle and syringe programmes (NSPs), and snowballing within peer networks. SETTING: NSPs in six suburbs throughout the Melbourne metropolitan area. PARTICIPANTS: One hundred and fifty-four current IDUs. The mean age was 28 years, 62% were male, and 80% nominated heroin as preferred drug. MEASUREMENTS: Interviewer-administered survey including questions about socio-demographics, drug use and main reasons for participating in research. FINDINGS: IDU research participation reasons were consistent with motivational themes such as economic gain (46%), expression of citizenship (38%), altruism (19%), personal satisfaction (17%), drug user activism (16%) and seeking information or assistance (5%). Most respondents (58%) cited reasons where the primary beneficiaries of participation were other individuals or groups (citizenship, altruism, drug user activism) or both self and others. CONCLUSIONS: IDU motivations for research involvement appear to be multi-dimensional, rarely motivated by economic gain alone, and not necessarily defined by direct benefits or gains to themselves. These findings are relevant to the question of IDU research payment ethics.

Adolescent↗
PubMed2000

Prospective study of prognostic factors in community-acquired bacteremic pneumococcal disease in 5 countries.

To define the influence of prognostic factors in patients with community-acquired pneumococcal bacteremia, a 2-year prospective study was performed in 5 centers in Canada, the United States, the United Kingdom, Spain, and Sweden. By multivariate analysis, the independent predictors of death among the 460 patients were age >65 years (odds ratio [OR], 2.2), living in a nursing home (OR, 2.8), presence of chronic pulmonary disease (OR, 2.5), high acute physiology score (OR for scores 9-14, 7.6; for scores 15-17, 22; and for scores >17, 41), and need for mechanical ventilation (OR, 4.4). Of patients with meningitis, 26% died. Of patients with pneumonia without meningitis, 19% of those with >/=2 lobes and 7% of those with only 1 lobe involved (P=.0016) died. The case-fatality rate differed significantly among the centers: 20% in the United States and Spain, 13% in the United Kingdom, 8% in Sweden, and 6% in Canada. Differences of disease severity and of frequencies and impact of underlying chronic conditions were factors of probable importance for different outcomes.

Aged↗
PubMed2000

Early experience in the use of Levovist ultrasound contrast in the evaluation of liver masses.

The aim of the present paper was to assess the utility of Levovist in defining the pathology of liver masses. Levovist is a new ultrasound contrast agent consisting of galactose microparticles, air bubbles and palmitic acid. Prospective studies were performed in patients referred for further evaluation of known liver masses. Levovist was peripherally injected and colour Doppler ultrasound studies were performed. Findings were correlated with clinicopathology and three other imaging modalities: biphasic spiral CT, CT arterial portography and contrast MRI. Twenty-five patients were studied (15 male and 10 female) in the age range 25-74 years. Liver masses ranged from 0.5 to 7 cm in maximum diameter. Thirteen lesions were benign and 12 were malignant (four hepatomas (HCC) and eight metastases). Levovist enhancement occurred in 18 lesions. Of these, six were benign (four focal nodular hyperplasias (FNH) and two haemangiomas). All 12 malignant lesions demonstrated enhancement. The HCC showed a mosaic pattern of central and peripheral enhancement, and the FNH demonstrated a spoke-wheel pattern. It was not possible to distinguish between haemangiomas and malignant lesions. Non-enhancing lesions may well be benign, with all malignancies showing some enhancement. Characteristic enhancement patterns were found for HCC (mosaic) and FNH (spoke-wheel). It was not possible to distinguish between metastases and benign lesions (haemangiomas) when the pattern of enhancement was peripheral.

Adult↗
PubMed2000

Tissue iodine content and serum-mediated 125I uptake-blocking activity in breast cancer.

In the thyroid, active transport of iodide is under control of the TSH-dependent Na+/I- symporter (NIS), whereas in the breast such control is less well understood. In this study, NIS expression was demonstrated by RT-PCR in 2 of 2 fibroadenomata and 6 of 7 breast carcinoma messenger ribonucleic acid isolates. In addition, mean total tissue iodine levels of 80.9 +/- 9.5 ng I/mg protein in 23 benign tumors (fibroadenomata) were significantly higher than those in 19 breast cancers taken from either the tumor (18.2 +/- 4.6 ng I/mg) or morphologically normal tissue taken from within the tumor-bearing breast (31.8 +/- 4.9 ng I/mg; P < 0.05 in each case). Inhibition of 125I uptake into NIS-transfected CHO cells was observed in serum from 20 of 105 (19.0%) breast carcinoma, 8 of 49 (16.3%) benign breast disease, and 27 of 86 (31.4%) Graves' patients, but in only 1 of 33 (3.0%) age-matched female controls. IgG purified from serum of patients showing positive 125I uptake inhibition also inhibited iodide uptake, suggesting that such inhibition was antibody mediated. 125I uptake inhibition was significantly associated with thyroid peroxidase antibody positivity (P < 0.05) in sera from breast cancer patients, but not in those with benign breast disease, once again suggesting an association between thyroid autoimmunity and breast carcinoma.

Animals↗
PubMed1998

Infection with HIV and hepatitis C virus among injecting drug users in a prevention setting: retrospective cohort study.

OBJECTIVES: To estimate the incidence of HIV and hepatitis C virus and risk factors for seroconversion among a cohort of injecting drug users. DESIGN: Retrospective cohort study. SETTING: Primary healthcare facility in central Sydney. SUBJECTS: Injecting drug users tested for HIV-1 antibody (n=1179) and antibodies to hepatitis C virus (n=1078) from February 1992 to October 1995. MAIN OUTCOME MEASURES: Incidence of HIV-1 and hepatitis C virus among seronegative subjects who injected drugs and underwent repeat testing. Demographic and behavioural risk factors for hepatitis seroconversion. RESULTS: Incidence of HIV-1 among 426 initially seronegative injecting drug users was 0.17/100 person years (two seroconversions) compared with an incidence of hepatitis C virus of 20.9/100 person years (31 seroconversions) among 152 injecting drug users initially negative for hepatitis C virus. Incidence of hepatitis C virus among injecting drug users aged less than 20 years was 75.6/100 person years. Independent risk factors for hepatitis C virus seroconversion were age less than 20 years and a history of imprisonment. CONCLUSIONS: In a setting where prevention measures have contributed to the maintenance of low prevalence and incidence of HIV-1, transmission of hepatitis C virus continues at extremely high levels, particularly among young injecting drug users.

Adult↗
PubMed1998

Diffuse panbronchiolitis: case report and review of the literature.

Diffuse panbronchiolitis is an uncommon disease of unknown aetiology mainly occurring in Asian races. Treatment with erythromycin acting through unclarified mechanisms is promising and may improve the poor prognosis currently associated with the disease. A case is presented illustrating how the imaging features of the disease, particularly on high-resolution computed tomography, may be used to support a diagnosis suggested on clinical grounds.

Anti-Bacterial Agents↗
PubMed1997

Lymphomatoid granulomatosis: case report and review of the literature.

Lymphomatoid granulomatosis (LG) is an uncommon disease now regarded by most authors as an unusual form of lymphoma with the ability to affect any bodily system. The disease and its complications may result in a spectrum of radiological appearances. A case illustrating how cerebral lesions may mimic demyelinating plaque, neoplasm or infection and how pulmonary lesions may lead to pneumopericardium is presented. The difficulty in establishing a definitive diagnosis, due to the non-specificity of symptoms, pathological investigations and radiological appearances of the disease, is emphasized. Clinicians must therefore consider LG in their differential diagnoses, as delayed treatment may affect prognosis.

Adult↗
PubMed1997

Viridans streptococci in blood cultures. Can we see any patterns of species related to patient category? Review of 229 cases of positive cultures with viridans streptococci.

We present a review of 229 blood cultures with viridans streptococci collected during a period of eight and a half years from 1986 to 1994 at a teaching hospital in Sweden. The clinical significance of the growth of viridans streptococci is always uncertain, since these bacteria can be contaminants from the skin flora. Growth in more than one culture bottle strengthens the clinical value of the finding. The question was whether species identification might also help in the assessment of the clinical relevance of the finding. The results show that Streptococcus mitis occurs significantly more frequently in blood cultures from the departments dealing with cancer patients. Even with polymicrobial growth in blood cultures, S. mitis should be considered a pathogen of clinical relevance, not a contaminant.

Blood↗
PubMed1995

Uptake of halothane and isoflurane by mother and baby during caesarean section.

Twenty-three patients undergoing Caesarean section received either 0.5% halothane or 0.8% isoflurane to supplement nitrous oxide-oxygen anaesthesia. We studied the rate of uptake of the agents by the mother and fetus by measuring partial pressures in maternal arterial (Pa) and fetal umbilical venous (Puv) blood. Mean induction-delivery interval did not differ between the halothane (10.8 min) and isoflurane (11.7 min) groups. There were no differences in maternal heart rate, arterial pressure, pH and blood-gas tensions and fetal pH, blood-gas tensions or Apgar scores between the two groups. Isoflurane uptake by the mother was more rapid than halothane; at delivery, mean Pa of isoflurane as a fraction of the inspired partial pressure (Pl) was 0.44 compared with 0.35 for halothane (P < 0.05). Mean Puv as a fraction of maternal Pa at delivery was 0.71 for both agents; thus placental transfer was the same for both agents. Consequently mean Puv/Pl was greater for isoflurane (0.32) than halothane (0.26) (P < 0.05). We conclude that both halothane and isoflurane are suitable agents for general anaesthesia for Caesarean section. The rate of uptake of isoflurane by the mother during Caesarean section was more rapid than halothane. The rate of uptake by the fetus from the mother was the same for halothane and isoflurane, so that fetal partial pressure as a fraction of the inspired partial pressure was greater for isoflurane than halothane.

Adult↗
PubMed1995

Peripheral blood flow in the elderly during inhalational anaesthesia.

We investigated whether aging altered the peripheral vascular effects of inhaled anaesthetic agents. Forearm blood flow (FBF) was measured in 20 young (18-34 yrs) and 21 healthy elderly (60-79) patients receiving isoflurane or halothane with 66% nitrous oxide (N2O) in oxygen (O2). After etomidate 0.3 mg/kg and vecuronium 0.1 mg/kg, the trachea was intubated and controlled ventilation instituted with 66% N2O in O2. Halothane or isoflurane were administered to achieve end-tidal concentrations of 0.5% halothane or 0.9% isoflurane after 20 min. FBF was measured by venous occlusion plethysmography during the 20 min study period. Induction of anaesthesia with etomidate decreased FBF below baseline (awake) values in both elderly and young; intubation returned FBF to baseline values in the young but not in the elderly. FBF decreased below baseline values in young and elderly patients receiving halothane and in elderly patients receiving isoflurane but not in young patients receiving isoflurane. FBF was significantly greater in young patients receiving isoflurane than halothane after 20 min administration. We conclude that perfusion of forearm muscle and skin is maintained in the young but not in the elderly during anaesthesia with isoflurane/N2O. Perfusion of forearm muscle and skin decreases in both young and elderly patients during anaesthesia with halothane/N2O. The cardiovascular effects of isoflurane/N2O and halothane/N2O did not differ significantly in healthy elderly patients.

Adolescent↗
PubMed1994

A comparison of HIV risk between women and men who inject drugs.

Although there is growing evidence of differences between women and men who inject drugs (IDUs) in terms of level of risk for HIV infection, very little research has been conducted specifically addressing the risk practices of women IDUs. This study formed part of a national study of HIV infection risks in IDUs and the purpose of the present analysis was an exploration of gender differences in HIV risk practices, focusing on the HIV risk practices of IDU women. 1,245 IDUs from the inner city area of Sydney took part in this study. Of these, 908 were men and 331 were women. Notable results were that female respondents were more likely to report sharing needles, they injected heroin more times in a typical using month and were more likely to have shared with someone they later found out was HIV seropositive. Female respondents also reported more sexual partners than men, were more likely to engage in prostitution, and were more likely to have sexual partners who were themselves IDUs. The results provide support for the proposition that women who inject drugs may be at greater risk of HIV infection through both their drug taking and their sexual practices. Further research is needed to explore the reasons underlying the risk practices of women who inject drugs and an understanding of these factors needs to be incorporated into HIV risk-reduction and drug harm-reduction policies and programs.

Adolescent↗
PubMed1992

Effects of isoflurane and nitrous oxide in subanesthetic concentrations on memory and responsiveness in volunteers.

Awareness, defined as conscious memory during anesthesia, has been a problem in anesthesia practice. To determine the effect of isoflurane and nitrous oxide (N2O) on memory, 17 healthy adult volunteers were randomly assigned to receive isoflurane or N2O and received the alternate agent 1-2 weeks later. Each volunteer was studied at four end-tidal concentrations of each agent, consecutively 0.15, 0.3, 0.45, and 0.15 times the minimum alveolar concentration (MAC) for isoflurane or 0.3, 0.45, 0.6, and 0.3 times MAC for N2O. After 15-min equilibration at each end-tidal concentration, volunteers were tested for voluntary response to command and were presented with verbal information to be recalled after anesthesia. Volunteers were interviewed on the day after the study and tested for conscious and unconscious memory of the information presented during anesthetic administration. MAC-awake (the end-tidal concentration preventing voluntary response in 50% of volunteers) was 0.38 (0.35-0.42) times MAC for isoflurane and 0.64 (0.61-0.68) MAC for N2O (means, 95% confidence limits), indicating isoflurane to be more potent than N2O in suppressing voluntary response (P = .0001). Memory data were analyzed in 12 volunteers who completed the study and in whom the allocation of information to be recalled was counterbalanced among agents and concentrations of agents. Memory was decreased by increasing concentrations of both agents. Conscious memory of the information presented during anesthetic administration was prevented by 0.45 MAC isoflurane but not completely prevented by 0.6 MAC N2O. Unconscious memory (defined as memory of information without conscious recognition) occurred during administration of both agents and was prevented by 0.45 MAC isoflurane but not by 0.6 MAC N2O. Isoflurane was more potent in suppressing memory than MAC-equivalent concentrations of N2O. Using models of the relationship between dose of agent and suppression of memory, a dose of both agents was estimated that suppressed memory by 50% (ED50). The ED50 was 0.20 MAC for isoflurane (95% confidence intervals, 0.15-0.25), and 0.50 MAC for N2O (95% confidence intervals 0.43-0.55). We conclude that isoflurane and N2O suppress memory in a dose-dependent manner, and that isoflurane is more potent in preventing memory and voluntary response to command than MAC-equivalent concentrations of N2O.

Adolescent↗