Carbon monoxide poisoning treated with hyperbaric oxygen: metabolic acidosis as a predictor of treatment requirements.
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A retrospective case note analysis was made of patients who received hyperbaric oxygen for carbon monoxide poisoning and were admitted to the Royal Naval Hospital Haslar between 1991 and 1995. Males predominated (38 v 10) as did cases of deliberate self poisoning (31 v 17). The most common presenting feature was unconsciousness, which is an indication for hyperbaric oxygen and therefore reflects referral patterns. If patients had not recovered completely after one hyperbaric exposure further treatments were given. The initial hydrogen ion concentration of those requiring more than one treatment was significantly higher than those who recovered after the first treatment. The initial carboxyhaemoglobin (COHb) concentration showed only a trend to being higher in the multiple treatment group. Although metabolic acidosis is well recognised, its relationship to treatment requirements has not been shown previously. Initial COHb does not always correlate well with severity of poisoning which relates to the mechanism of toxicity of carbon monoxide: binding of carbon monoxide to the intracellular oxygen carrying proteins (for example cytochromes) rather than solely to haemoglobin. These findings are consistent with this mechanism and suggests that initial acidosis is a better predictor of treatment requirements and severity than initial COHb. (+info)
Perinatal risk and severity of illness in newborns at 6 neonatal intensive care units.
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OBJECTIVES: This multisite study sought to identify (1) any differences in admission risk (defined by gestational age and illness severity) among neonatal intensive care units (NICUs) and (2) obstetric antecedents of newborn illness severity. METHODS: Data on 1476 babies born at a gestational age of less than 32 weeks in 6 perinatal centers were abstracted prospectively. Newborn illness severity was measured with the Score for Neonatal Acute Physiology. Regression models were constructed to predict scores as a function of perinatal risk factors. RESULTS: The sites differed by several obstetric case-mix characteristics. Of these, only gestational age, small for gestational age. White race, and severe congenital anomalies were associated with higher scores. Antenatal corticosteroids, low Apgar scores, and neonatal hypothermia also affected illness severity. At 2 sites, higher mean severity could not be explained by case mix. CONCLUSIONS: Obstetric events and perinatal practices affect newborn illness severity. These risk factors differ among perinatal centers and are associated with elevated illness severity at some sites. Outcomes of NICU care may be affected by antecedent events and perinatal practices. (+info)
Mortality among homeless shelter residents in New York City.
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OBJECTIVES: This study examined the rates and predictors of mortality among sheltered homeless men and women in New York City. METHODS: Identifying data on a representative sample of shelter residents surveyed in 1987 were matched against national mortality records for 1987 through 1994. Standardized mortality ratios were computed to compare death rates among homeless people with those of the general US and New York City populations. Logistic regression analysis was used to examine predictors of mortality within the homeless sample. RESULTS: Age-adjusted death rates of homeless men and women were 4 times those of the general US population and 2 to 3 times those of the general population of New York City. Among homeless men, prior use of injectable drugs, incarceration, and chronic homelessness increased the likelihood of death. CONCLUSIONS: For homeless shelter users, chronic homelessness itself compounds the high risk of death associated with disease/disability and intravenous drug use. Interventions must address not only the health conditions of the homeless but also the societal conditions that perpetuate homelessness. (+info)
Factors associated with refusal to treat HIV-infected patients: the results of a national survey of dentists in Canada.
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OBJECTIVES: This study investigated dentists refusal to treat patients who have HIV. METHODS: A survey was mailed to a random sample of all licensed dentists in Canada, with 3 follow-up attempts (n = 6444). Data were weighted to allow for probability of selection and nonresponse and analyzed with Pearson's chi 2 and multiple logistic regression. RESULTS: The response rate was 66%. Of the respondents, 32% had knowingly treated HIV-infected patients in the last year; 16% would refuse to treat HIV-infected patients. Respondents reported willingness to treat HIV-infected patients (81%), injection drug users (86%), hepatitis B virus-infected patients (87%), homosexual and bisexual persons (94%), individuals with sexually transmitted disease(s) (94%), and recipients of blood and blood products (97%). The best predictors of refusal to treat patients with HIV were lack of ethical responsibility (odds ratio = 9.0) and items related to fear of cross-infection or lack of knowledge of HIV. CONCLUSIONS: One in 6 dentists reported refusal to treat HIV-infected patients, which was associated primarily with respondents' lack of belief in an ethical responsibility to treat patients with HIV and fears related to cross-infection. These results have implications for undergraduate, postgraduate, and continuing education. (+info)
Tobacco smoke exposure at one month of age and subsequent risk of SIDS--a prospective study.
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The aim of this investigation was to identify the sources of postnatal exposure to tobacco smoke at 1 month of age and to examine their relation to sudden infant death syndrome (SIDS). The Tasmanian Infant Health Survey was a prospective cohort study undertaken from 1988 to 1995. It involved 9,826 infants (89% of eligible infants) at higher risk of SIDS. Subsequently 53 eligible infants died of SIDS. Hospital interviews were available on 51 and home interviews on 35 SIDS infants. Urinary cotinine assays were conducted using gas-liquid chromatography (n = 100). Within a predictive model that explained 63% of urinary cotinine variance, the strongest predictor of cotinine and also of SIDS was maternal smoking, though the effects of prenatal and postnatal smoking could not be separated. However, for particular smoking-related behaviors, there was a discordance between prediction of cotinine concentration and prediction of risk of SIDS. If smoking mothers did not smoke in the room with the baby, the cotinine level in the infant's urine was reduced by a little more than a half (p = 0.009), but this was not associated with a reduction in SIDS risk (odds ratio = 1.09, 95% confidence interval 0.47-2.55). Similarly, the presence of other adult resident smokers was associated with a 63% increase in urinary cotinine (p = 0.047) but not with increased SIDS risk (odds ratio = 0.69, 95% confidence interval 0.34-1.40). However, the study lacked the power to detect modest effects, that is, those altering risk less than twofold. (+info)
Usefulness of D-dimer, blood gas, and respiratory rate measurements for excluding pulmonary embolism.
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BACKGROUND: A study was undertaken to assess the usefulness of the SimpliRED D-dimer test, arterial oxygen tension, and respiratory rate measurement for excluding pulmonary embolism (PE) and venous thromboembolism (VTE). METHODS: Lung scans were performed in 517 consecutive medical inpatients with suspected acute PE over a one year period. Predetermined end points for objectively diagnosed PE in order of precedence were (1) a post mortem diagnosis, (2) a positive pulmonary angiogram, (3) a high probability ventilation perfusion lung scan when the pretest probability was also high, and (4) the unanimous opinion of an adjudication committee. Deep vein thrombosis (DVT) was diagnosed by standard ultrasound and venography. RESULTS: A total of 40 cases of PE and 37 cases of DVT were objectively diagnosed. The predictive value of a negative SimpliRED test for excluding objectively diagnosed PE was 0.99 (error rate 2/249), that of PaO2 of > or = 80 mm Hg (10.7 kPa) was 0.97 (error rate 5/160), and that of a respiratory rate of < or = 20/min was 0.95 (error rate 14/308). The best combination of findings for excluding PE was a negative SimpliRED test and PaO2 > or = 80 mm Hg, which gave a predictive value of 1.0 (error rate 0/93). The predictive value of a negative SimpliRED test for excluding VTE was 0.98 (error rate 5/249). CONCLUSIONS: All three of these observations are helpful in excluding PE. When any two parameters were normal, PE was very unlikely. In patients with a negative SimpliRED test and PaO2 of > or = 80 mm Hg a lung scan is usually unnecessary. Application of this approach for triage in the preliminary assessment of suspected PE could lead to a reduced rate of false positive diagnoses and considerable resource savings. (+info)
Primary prevention of CHD: nine ways to reduce risk.
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Lowering cholesterol can reduce the incidence of coronary heart disease. Treating hypertension reduces overall mortality and is most effective in reducing the risk of coronary heart disease in older patients. Smoking cessation reduces the level of risk to that of nonsmokers within about three years of cessation. Aspirin is likely to be an effective means of primary prevention, but a group in whom treatment is appropriate has yet to be defined. Evidence that supplementation with vitamin A or C reduces the risk of coronary heart disease is inadequate; the data for use of vitamin E are inconclusive. Epidemiologic evidence is sufficient to recommend that most persons increase their levels of physical activity. Lowering homocysteine levels through increased folate intake is a promising but unproven primary prevention strategy. Hormone replacement therapy was associated with reduced incidence of coronary heart disease in epidemiologic studies but was not effective in a secondary prevention trial. (+info)
Exercise training enhances endothelial function in young men.
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OBJECTIVES: The present study was designed to assess whether exercise training can enhance endothelium-dependent dilatation in healthy young men. BACKGROUND: Exercise has been shown to reduce cardiovascular morbidity and mortality, but the mechanisms for this benefit are unclear. Endothelial dysfunction is an early event in atherogenesis, and animal studies have shown that exercise training can enhance endothelial function. METHODS: We have examined the effect of a standardized, 10-week, aerobic and anaerobic exercise training program on arterial physiology in 25 healthy male military recruits, aged 17 to 24 (mean 20) years, of average fitness levels. Each subject was studied before starting, and after completing the exercise program. Baseline vascular reactivity was compared with that of 20 matched civilian controls. At each visit, the diameter of the right brachial artery was measured at rest, during reactive hyperemia (increased flow causing endothelium-dependent dilation) and after sublingual glyceryltrinitrate (GTN; an endothelium-independent dilator), using high-resolution external vascular ultrasound. RESULTS: At baseline, flow-mediated dilatation (FMD) and GTN-mediated dilatation were similar in the exercise and control groups (FMD 2.2+/-2.4% and 2.4+/-2.8%, respectively, p = 0.33; GTN 13.4+/-6.2 vs. 16.7+/-5.9, respectively, p = 0.53). In the military recruits, FMD improved from 2.2+/-2.4% to 3.9+/-2.5% (p = 0.01), with no change in the GTN-mediated dilation (13.4+/-6.2% vs. 13.9+/-5.8%, p = 0.31) following the exercise program. CONCLUSION: Exercise training enhances endothelium-dependent dilation in young men of average fitness. This may contribute to the benefit of regular exercise in preventing cardiovascular disease. (+info)