Anthony E. Camilli

Respiratory effects of non-tobacco cigarettes.

Data from the Tucson epidemiological study of airways obstructive disease on smoking of non-tobacco cigarettes such as marijuana were analysed to determine the effect of such smoking on respiratory symptoms and pulmonary function. Among adults aged under 40, 14% had smoked non-tobacco cigarettes at some time and 9% were current users. The prevalence of respiratory symptoms was increased in smokers of non-tobacco cigarettes. After tobacco smoking had been controlled for men who smoked non-tobacco cigarettes showed significant decreases in expiratory flow rates at low lung volumes and in the ratio of the forced expiratory volume in one second to the vital capacity. This effect on pulmonary function in male non-tobacco cigarette smokers was greater than the effect of tobacco cigarette smoking. These data suggest that non-tobacco cigarette smoking may be an important risk factor in young adults with respiratory symptoms or evidence of airways obstruction.

The epidemiological importance of intraindividual changes in objective pulmonary responses

Debate continues about what constitutes significant and meaningful change in health status of individuals and populations. More importantly, the basic biological and medical criteria that are used for clinical and environmental judgments require further discussion and clarification. What proportion of loss of cardio-pulmonary function, overt disability, or mortality is sufficient to determine an ≫ adverse health effect ≫? Health-oriented individuals, including researchers and clinicians, may choose to adhere to different criteria than other professional groups (e.g., legal, social). It is proposed in this paper that criteria for defining adverse health effects should represent clinically meaningful, as distinct from only statistically significant, responses. These include pulmonary function test results that indicate obstructive or restrictive diseases, and electrocardiogram results indicating coronary artery disease. Intraindividual changes that predict a meaningful medical change would be included; these changes should meet specific requirements in terms of what constitute normal vs. abnormal ranges of variation. Further, the proportion of the population defined to be impaired should be considered. These issues are the focus of this paper.

Effects of passive smoking on theophylline clearance

Theophylline disposition was examined in seven passive smokers, defined as nonsmokers with long‐term exposure to cigarette smoke, and seven age‐matched nonsmokers with minimal smoke exposure. Subjects were given an intravenous infusion of aminophylline (6 mg/kg) and blood samples were drawn before and during the 48‐hour postinfusion period. Clearance for passive smokers was 6.01 × 10−2 L/hr · kg and for nonsmokers, clearance was 4.09 × 10−2 L/hr · kg (p < 0.025). Terminal elimination half‐life for passive smokers was 6.93 hours versus 8.69 hours for nonsmokers (p < 0.05). The mean residence time for passive smokers was 9.89 hours. For nonsmokers, the mean residence time was 13.11 hours (p < 0.05). These measurements were statistically different, whereas there was no difference in volume of distribution between the groups, suggesting that passive smokers metabolize theophylline more rapidly than nonsmokers. Plasma and urine cotinine and nicotine concentrations were measured in all subjects. There was a significant difference between the subject groups in plasma (p < 0.004) and urine (p < 0.002) cotinine concentrations. Theophylline clearance correlated with both plasma (r = 0.73, p < 0.01) and urine (r = 0.79, p < 0.01) cotinine concentrations. Additional studies should be conducted to further define the pharmacokinetic characteristics of passive smokers and to assess the effects of passive smoking on drugs metabolized by the mixed function oxidase system.

Asthmatic risk factors and bronchial reactivity in non-diagnosed asthmatic adults

Specific respiratory signs and symptoms are thought to occur prior to diagnoses of asthma as part of the natural history. These signs and symptoms include: high IgE, a history of wheezing symptoms, and/or excessive declines in lung function. The first two are thought to distinguish asthma from other airway obstructive diseases (AOD). To predict subsequent AOD, twelve years of follow-up (1972–84) data from the Tucson longitudinal epidemiological study of AOD in a community population were evaluated on 687 subjects aged 19–70 years on entry. To determine the likelihood that non-asthmatics that have these specific risk factors would have marked or intermediate bronchial reactivity to methacholine, an experimental study was performed. This was done in 1984–85 in a robust, efficient post-hoc stratified sample of male subjects ages 30–55 from the population followed from 1972. They were subsequently followed through 1991. Persistent symptoms best predicted final pulmonary function and new diagnosed AOD in subjects in the population. Previously diagnosed AOD also predicted lower pulmonary function. The experimental results indicate that predisposition to reactivity appears likely without the presence of diagnosed asthma. Further, the experimental subjects with high risk had increased symptomatology and decreased lung function when tested at follow-up; not all of the reactivity was explained by these factors. An attempt to predict reactivity by physician evaluation and special questionnaire was not fruitful. In addition, wheeze per se often disappeared without later evidence of asthma (or AOD) diagnosis, questioning some international tendencies to label all wheeze as asthma. Thus, high IgE significantly predicted bronchial responsiveness, but high IgE and symptoms are neither necessary nor sufficient. Also, both preclinical and clinical asthma predict eventual low lung function.

Analytic Reviews : Red Cell Transfusion in a Critical Care Unit

The acquired immunodeficiency syndrome epidemic and recognition of human immunodeficiency virus transmission by blood products have increased concern over the risks of blood transfusion and generated discus sion on proper indications. To assess current practice with respect to red blood cell transfusion, we examined transfusion practices in a medical-surgical intensive care unit. The extensive clinical and physiological moni toring in this setting allowed us to examine indices of oxygen carrying capacity, oxygen delivery, tissue oxy genation, and their associations with subsequent trans fusion. We were unable to detect changes in hemody namic or tissue oxygenation measurements associated with transfusions. Tissue oxygenation measures were in frequently documented even in the presence of an in dwelling pulmonary artery catheter. Hemoglobin and hematocrit levels showed statistically significant de creases prior to initial and subsequent transfusions. He modynamic and tissue oxygenation indices available in intensive care settings merit further evaluation for use in the assessment of transfusion need.