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Biomedical subjects

A S McLean

Publications and source records attributed to A S McLean.

At least 19 recordsLinked to original sources
PubMed2006

Endotoxin stimulated interleukin-10 production is enhanced by adenosine. Possible key to septic shock associated immune deficiency?

The aim of this bench study was to investigate whether adenosine influences secretion of interleukin-10 (IL-O) in human whole blood culture stimulated with lipopolysaccharide. Whole blood from healthy human volunteers was mixed ex vivo in 1:1 ratio with RPMI 1640 culture medium and subsequently cultured at 37 degrees C with or without adenosine (total of 120 microM added in four aliquots over two hours) in the presence or absence of 100 ng/ml lipopolysaccharide for four and eight hours, respectively. There was only a minimal IL-10 production after four hours of culture regardless of the experimental conditions. However, lipopolysaccharide stimulated whole blood cultures with added adenosine released large amounts of IL-lO after eight hours. The response was similar whether adenosine was added before (5.99 pg/ml/10(6) leucocytes) or after (10.35 microg/ml/10(6) leucocytes) stimulation with lipopolysaccharide and interindividual variation was present. In conclusion adenosine enhances lipopolysaccharide stimulated IL-10 production in whole human blood and may contribute to the IL-10 mediated immune dysfunction in sepsis.

Adenosine↗
PubMed2004

The correlation between airborne methicillin-resistant Staphylococcus aureus with the presence of MRSA colonized patients in a general intensive care unit.

Air sampling directly onto a methicillin-resistant Staphylococcus aureus (MRSA) selective agar was performed at six locations three times weekly over a period of 32 weeks in a new, initially MRSA-free Intensive Care Unit to examine if MRSA is present in air sample cultures and, if so, whether it is affected by the number of MRSA colonized patients present. A total of 480 air samples were collected on 80 days. A total of 39/480 (8.1%) samples were found to be MRSA positive of which 24/160 (15%) positive air samples were from the single rooms, where MRSA colonised patients were isolated, and 15/320 (4.7%) were from the open bed areas. A significant correlation was found between the daily number of MRSA colonized or infected patients in the Unit and the daily number of MRSA positive air samples cultures obtained (r2=0.128; P<0.005). The frequency of positive cultures was significantly higher in the single rooms than in the open bed areas (relative risk=3.2; P<0.001). The results from one of the single rooms showed a strong correlation between the presence of MRSA patients and MRSA positive air samples (relative risk=11.4; P<0. 005). Our findings demonstrate that the presence of airborne MRSA in our unit is strongly related to the presence and number of MRSA colonized or infected patients in the Unit.

Air Microbiology↗
PubMed2003

Increased B-type natriuretic peptide (BNP) level is a strong predictor for cardiac dysfunction in intensive care unit patients.

Patients admitted to an Intensive Care Unit (ICU) frequently have underlying cardiac dysfunction. Early interventions are sometimes difficult to initiate because of diagnostic uncertainty as to whether cardiac failure is present As B-type natriuretic peptide (BNP) has been shown to be increased in cardiac dysfunction, we sought to demonstrate whether BNP can be used as a screening tool for cardiac dysfunction in patients admitted to ICU. All patients admitted to a combined medical and surgical ICU over a four-week period were included in the study. BNP was measured on the point of admission using a hand-held meter. Clinicians were blinded from the measurement when diagnoses were made as to whether or not the patients had clinically significant cardiac dysfunction. Patients with cardiac dysfunction had a significantly higher level of BNP when compared to the non-cardiac dysfunction group: 516 +/- 385 pg/ml (n = 26) v 67 +/- 89 pg/ml (n = 58) (P < 0.0001) A BNP cut-off value at 144 pg/ml exhibited a 92% sensitivity, 86% specificity and 96% negative predictive value. The sensitivity improved to 96% when the analysis was confined to patients > or = 55 years. At this cut-off value, BNP is a strong predictor of cardiac dysfunction. BNP measurement offers a rapid and affordable way to screen for cardiac dysfunction in patients admitted to ICU. An increased BNP level warrants further cardiac investigations so as to implement early interventions for cardiac decompensation in ICU patients.

Aged↗
PubMed1998

Transoesophageal echocardiography in the intensive care unit.

The role of transoesophageal echocardiography (TOE) in a general intensive care unit was examined by reviewing all studies performed in a major metropolitan hospital over a two-year period. TOE was performed on 53 patients where transthoracic studies were inadequate, the indications being cardiac source of embolus (13/53), thoracic aorta abnormalities (5/53), left ventricular systolic function (22/53), endocarditis (6/53), right heart pathology (2/53), pulmonary embolus (2/53), or a potentially surgical correctable lesion (3/53). Findings were categorized into three groups: confirming suspected pathology (18/53), major incidental findings (6/53), or normal (29/53). Patient management was altered, not only by the finding of positive pathology, but also after identifying normal left ventricular systolic function (14/53). Echocardiography has become an invaluable tool in the ICU setting.

Adult↗
PubMed1998

Cardiac tamponade in a postpartum woman with Lemierre's syndrome.

A 23-year-old primigravida with Lemierre's syndrome developed pericardial tamponade secondary to mediastinal infection and anticoagulant therapy. Intrathoracic echocardiographic diagnosis during a period of cardiac arrest led to urgent pericardiocentesis and successful resuscitation.

Adult↗
PubMed1997

Estimation of cardiac output by noninvasive echocardiographic techniques in the critically ill subject.

We evaluated the accuracy of cardiac output estimations by three transthoracic echocardiographic techniques in critically ill subjects. This study was a prospective comparison study carried out in a general intensive care unit of a teaching hospital. The subjects had a broad range of diagnoses including pulmonary embolus, cardiogenic shock, septic shock, Legionnaire's disease and perioperative myocardial infarction. All patients requiring pulmonary artery catheterization underwent echocardiographic cardiac assessment with comparison of findings to those obtained by thermodilution techniques. Nineteen studies on eighteen patients were performed, with cardiac output calculated by the two-chamber Simpson's, four-chamber Simpson's, and left ventricular outflow tract (LVOT) Doppler methods. Acceptable data was obtained in those patients without mitral regurgitation. There was good correlation between the thermodilution technique and Simpson's two-chamber method (r = 0.91), but less so with the Simpson's four-chamber method (r = 0.77). All studies were included in the LVOT Doppler method with a good correlation (r = 0.94). A plot of differences between methods using the Bland and Altman statistical method indicated that only the LVOT Doppler method demonstrated acceptable agreement with a mean of 0.2 litres/minute, standard deviation of 0.82 litres/minute and 95% limits of agreement of -1.5 to +1.9 litres/minute. We concluded that the LVOT Doppler method was the only one which demonstrated acceptable agreement between the thermodilution method and echocardiographic techniques in all critically ill patients studied.

Adolescent↗
PubMed1996

Echocardiography assessment of left ventricular function in the critically ill.

Echocardiography is fast becoming the technique of choice for noninvasive evaluation of left ventricular function in the critically ill patient. Current technology allows for assessment of overall left ventricular performance and for diastolic and systolic function. Doppler technology has greatly enhanced the diagnostic capability of two-dimensional echocardiography. The critical care physician should be aware not only of currently available techniques, but also those which will be used in the routine care of the critically ill subject in the foreseeable future.

Critical Care↗
PubMed1995

Australian intensive care educational links with Asian countries.

A survey examining the level of Australian Intensive Care Unit involvement in the education of Asian critical care doctors and nurses was performed. Of the 49 hospitals surveyed, 34% have ongoing links. An analysis of countries involved, proportion of medical and nursing numbers, and whether the teaching was performed in Australia or the Asian country was undertaken. The survey revealed that a high proportion of Australian Intensive Care Units are actively involved, or would consider future participation, in educational links with Asian units.

Asia↗
PubMed1992

Vasopressor therapy in cardiac resuscitation.

The standard 0.5 to 1.0 mg dose of adrenaline used in cardiac resuscitation may be inadequate on the basis of theoretical and experimental evidence. Well designed clinical trials are indicated to test the hypothesis that higher doses of adrenaline could be more effective in specific subgroups of people experiencing cardiac arrest. The success in resuscitation is related to the aortic diastolic pressure and the effectiveness of adrenaline relates to its peripheral vasopressor effect. Other catecholamines such as noradrenaline may be more efficacious, as could be non-adrenergic vasopressors. Clinical studies are required, however, to evaluate these potential alternatives.

Animals↗
PubMed1991

Trauma studies. I. Metropolitan Sydney trauma data.

A review of trauma statistics in metropolitan Sydney over a three-year period was undertaken. Data were obtained from the NSW Department of Health on hospital separations for trauma diagnoses for the two financial years 1985-1986 and 1988-1989 and from the Roads and Traffic Authority of New South Wales and the NSW Ambulance Service. Marked differences emerged in the pattern of overall trauma between the 1985-1986 and 1988-1989 periods, the most noteworthy being the reduction of teaching hospital separations both for total trauma and for transport related trauma which is responsible for the majority of serious injuries. The implementation of a State-wide policy for trauma services in New South Wales is now occurring. The information obtained from this study indicates that much of the baseline data used in formulating that policy were misleading. The policy of concentrating major trauma resources (level 3 trauma centres) in the eastern half of the city is found to be at odds with the finding of a high morbidity and mortality from transport related trauma in the western half of the city and the lack of such resources in that area.

Accidents, Traffic↗
PubMed1991

Trauma studies. II. A review of trauma in a Sydney metropolitan hospital.

Trauma is the leading cause of death for people aged under 40 years in Australia. However, data on trauma in this country have been scant and derived from teaching hospitals or "non-medical" sources such as Roads and Traffic Authority reports. To address this, a review was undertaken of trauma separations from a large suburban hospital. The Nepean Hospital is a 350-bed metropolitan hospital on the western fringe of Sydney and, since the development of "Areas" as the basic health planning units in metropolitan Sydney, it is the main hospital of the Wentworth Area Health Service. A retrospective study of trauma presentations to the hospital was undertaken to provide a "snapshot" of the hospital's trauma load. Epidemiological factors leading to this load were reviewed, together with deaths, ambulance transfers and transfers by other means. During the study period there were 2042 separations for trauma based on the International Classification of Diseases codes E800-E999. Thirty-four other patients were transferred or died without being admitted to the hospital and 72 patients were transferred after hospital admission. During this period 1236 potentially severely injured patients were seen. This study demonstrates the large trauma load presenting to a Sydney suburban hospital and shows that planning for trauma services must take account of the size and logistics of such a load. As epidemiological indices suggest that the load will increase, further accurate data on suburban trauma are needed to allow proper planning.

Accidents, Traffic↗