Diagnostic accuracy of paediatric echocardiograms interpreted by individuals other than paediatric cardiologists.

OBJECTIVE: To assess the diagnostic error rate among echocardiograms undertaken by individuals other than paediatric cardiologists in our referral area. METHODOLOGY: External group: The charts and echocardiographic results of all patients who had undergone outside echocardiograms between January 1996 and December 1999 were reviewed (110). Age at echocardiography, diagnostic complexity, presence of any diagnostic errors and the severity of any diagnostic errors were identified. Internal group: To assess our own error rate, the initial echocardiographic diagnoses of 100 patients undergoing cardiac catheterisation or corrective surgery were compared with the post-catheterisation or postoperative diagnoses. Age and diagnostic complexity were also assessed in the control group. RESULTS: Diagnostic errors occurred in 47/110 patients (44%) of the externally studied group (of which 24% were either major or life threatening) as opposed to 3/100 of the internally studied group, despite the internally studied group being of increased diagnostic complexity. Errors were more common and of increased severity in infants less than 1 month of age but extended throughout all age groups. Major and life threatening errors increased with increasing diagnostic complexity. In the externally studied group, 8/47 errors were patients inappropriately designated as normal. Four of these patients required cardiac surgery or interventional cardiac catheterisation. CONCLUSIONS: This study suggests an unacceptably high error rate in paediatric echocardiographic diagnoses by non-paediatric cardiologists throughout all age groups. Such errors are more likely in younger infants and with increasing diagnostic complexity.

Predictors of sun protective behaviors among school students.

A random sample of students (N = 3,655) in Grades 7, 9, and 11 from 55 schools in Queensland (Australia) were surveyed about their sun protection knowledge, attitudes, and behaviors. An aggregate sun protection behavior index (SPBI) was developed from self-reported behaviors on a school day and a weekend day. Repeated measures regression analyses revealed that negative views of sun protection measures were associated with low scores on the SPBI, an association that was strongest among older students and in larger schools. Low perceived parental sun protective behaviors were associated with low SPBI ratings, and this association was greatest in small schools and on Saturdays. Older students had lower SPBI ratings, but their scores increased on Saturdays. Gender did not appear to be independently related to the SPBI after adjustment for the other variables. These findings reinforce the need for adolescent sun protection programs to address the complex interactions among psychological, social, and environmental factors that influence different subgroups of the student population.

Predictors of demand for emergency prehospital care: an Australian study.

INTRODUCTION: Determining the predictors of demand for emergency prehospital care can assist ambulance services in undertaking policy and planning activities. HYPOTHESIS: Demand for prehospital care can be explained by demographic, health status, and economic determinants. METHODS: The study used a cross-sectional design to investigate the association of demographic, health status, and insurance factors with the use of prehospital, ambulance care. Core data items including age, gender, marital status, country of origin, triage score, diagnosis, time of presentation, method of arrival, and patient disposition were collected for every patient who presented at the Emergency Department of the study hospital over a four-month period. Ambulance usage was analysed using Poisson regression. RESULTS: For the 10,229 patients surveyed, only a small number were triaged as having the highest level of urgent medical need (0.8%), but the majority of these used prehospital emergency medical care (90.2%). Predictors of ambulance use included age > 65 years (Prevalence Ratio [PR] = 2.92; 95% confidence interval [CI]: 2.35-3.63), being married or in a de-facto relationship (PR = 0.69; 95% CI: 0.60-0.79) or divorced, separated, or widowed (PR = 0.83; 95% CI: 0.70-0.98), triage score level 1 or 2 (PR = 1.95; 95% CI: 1.68-2.28), or triage score level 3 (PR = 1.54; 95% CI: 1.38-1.72), diagnosis involving either mental (PR = 4.29; 95% CI: 1.84-10.01), nervous (PR = 2.74; 95% CI: 1.19-6.31) or trauma (PR = 2.33; 95% CI: 1.03-5.27) conditions, and insurance status (PR = 1.54; 95% CI: 1.40-1.71). Ethnicity, gender, and time of day were not associated with usage. CONCLUSION: Demand for ambulance services can be predicted by a number of demographic, medical status, and insurance variables. Age and triage levels are key influences on demand for ambulance services. Ambulance insurance status provides an economic incentive to use ambulance services regardless of the urgency of the medical condition.

Public health risks of the flesh of farmed crocodiles.

The farming of crocodiles in the Northern Territory of Australia is a rapidly growing industry. The saltwater crocodile produces a premium quality skin which is sought world-wide for the lucrative leather trade and manufacture of finished articles. Flesh is considered to be a by-product of skin production. Several procedures are used in abattoirs to prevent the risk of cross contamination of flesh. The public health risks linked to the production of crocodile flesh are described for the two main diseases of concern, namely: sparganosis and salmonellosis. The slaughter and hygienic processing procedures and local laboratory evidence indicate that the consumption of crocodile flesh produced in the Northern Territory carries a negligible public health risk.

Brainstem auditory evoked response during propofol anaesthesia in children.

The effect of propofol on the brainstem auditory response was studied in 10 healthy children presenting for elective general surgery. A computer-controlled infusion of propofol was used to induce and maintain anaesthesia. Basal brainstem auditory evoked responses were recorded in the awake child and at different infusion rates of propofol. Significant increases in the latencies of the brainstem waves III and V and the interpeak intervals I-V and III-V were seen and were dose dependent. The changes were small and would not preclude the use of propofol anaesthesia for brainstem auditory evoked response testing in children.

Continuous extradural analgesia: comparison of midwife top-ups, continuous infusions and patient controlled administration.

We have compared three techniques used to provide extradural analgesia during the first stage of labour: 0.25% plain bupivacaine 10 ml demand top-ups delivered by the midwife; continuous infusion of 0.125% plain bupivacaine 10 ml h-1; and patient-controlled extradural analgesia (PCEA) delivering 3-ml boluses of 0.25% bupivacaine. Each technique produced comparable analgesia achieving equivalent maternal satisfaction, with no difference in mode of delivery and no complications. This regimen for PCEA proved a viable alternative for continuous extradural analgesia and was popular with the mothers, midwives and anaesthetists.

Cause of death after critical illness.

This study reports the causes of death after discharge following treatment of life-threatening illness on an Intensive Therapy Unit. Details of survivors discharged between June 1985 and December 1988 were sent to the Registrar General for Scotland who subsequently issued copies of death certificates of those patients who had died between discharge and 1 January 1990. The results show that the commonest causes of death after discharge were malignancy and respiratory failure, although there is wide variation in the post-discharge mortality rates for different diagnostic categories. The admission diagnoses were identical to, or contributed to, the causes of death in 64% of patients who died after discharge. Eighty-five percent of patients who died from the same condition which prompted admission did so within a year following discharge, but after 2 years no deaths were attributed to the admission diagnosis.

Effective use of regional intensive therapy units.

OBJECTIVE: To determine the effectiveness of regional intensive therapy units. DESIGN: Retrospective and prospective study of patients transferred to a regional intensive therapy unit over four years. SETTING: Glasgow regional intensive therapy unit. MAIN OUTCOME MEASURES: Severity of illness was assessed at the time of referral to the unit with the acute physiological and chronic health evaluation (APACHE) scoring system. Mortality was calculated. RESULTS: A significant association was found between increasing duration of illness before transfer and mortality, which was independent of the severity of illness. Mortality also varied depending on the referring hospital. CONCLUSIONS: When transfer of critically ill patients is required this should be done as early as possible to make best use of the services available. The mortality of patients transferred after 10 days casts doubt on whether further aggressive intensive therapy is appropriate.

Acute fatty liver of pregnancy: clinical features and diagnosis.

Five cases of acute fatty liver of pregnancy are described. These are the only recognized cases of this disorder occurring in a 2 year period in Western Australia. Clinical and laboratory features are presented. There was no maternal death. Of the six babies, there were three intrauterine deaths, including the only set of twins. All the babies were male. Vomiting in the third trimester was the chief presenting feature in all cases, often accompanied by a systemic illness with malaise and tiredness. Extreme polydipsia was noted as a prominent symptom in all cases. The combination of moderately abnormal liver function tests, extreme leucocytosis with other blood film abnormalities, hypoglycaemia, impaired renal function, coagulopathy and gross elevation of uric acid level is regarded as highly suggestive of the diagnosis. Features of a preeclamptic illness were present in several cases. Three of the patients have since had uneventful pregnancies. The constellation of clinical and laboratory features is sufficiently characteristic to allow accurate clinical diagnosis in most cases of this disorder. The chances of both maternal and fetal survival are enhanced by early diagnosis allowing intervention in the form of prompt delivery of the infant.

Normal haematological and biochemical values for the swamp buffalo (Bubalus bubalis) in Australia.

Blood samples were collected from 24 immature male, 55 immature female and 99 mature female water buffalo kept at an experimental farm in the Northern Territory. Haematological analysis was performed on blood collected in dipotassium--ethylene diamine tetra acetic acid while biochemical analysis was performed on serum and plasma (for glucose) samples. Haematological values of mature buffalo were similar to those recorded for swamp buffalo in Malaysia. Blood cell appearances were similar to those reported for adult Indian river buffalo though values recorded for red cell components were higher. Statistical analysis revealed no significant differences between immature male and female buffalo. Red cell components, eosinophils, total plasma and serum proteins, albumin, gamma globulins, inorganic phosphate and the enzyme gamma-glutamyl transferase were significantly higher for mature female buffalo when compared to immature females. Reasons for the differences were not fully determined but the effect of age and nutritional status in combination with a variable period of domestication were considered.

Interaction of cultured mammalian cells with WR-2721 and its thiol, WR-1065: implications for mechanisms of radioprotection.

An isothermal microcalorimeter was used to measure changes in heat flow when radioprotective drugs were added to cultured mammalian cells. The heat produced when WR-2721 was added continued for at least 90 min. WR-2721 was dephosphorylated by the cells to thiol (WR-1065) which oxidizes to disulphide. In the microcalorimeter, thiols give an immediate burst of heat due to this oxidation. A biological oxygen monitor revealed that WR-1065 and cysteamine rapidly consumed all the oxygen in culture medium. (10 mM WR-1065 deoxygenated medium in 2 min.) Rapid consumption of oxygen by radioprotective thiols indicates that they will not co-exist with oxygen for long in cells. This has two important implications with respect to mechanisms of radioprotection: (1) oxygen in tissues will be consumed rapidly and could result in local hypoxia; and, (2) at modest doses of protective agents the thiol will be consumed in oxic cells and hence very little will be available for reactions such as hydrogen donation. Our results indicate that anoxia is probably the principal mechanism of protection by aminothiols in mammals and aerated cells. This has major implications for clinical applications of radioprotectors and these are discussed.