Twenty-four patients completed a double-blind, randomized clinical trial comparing the effects of nifedipine GITS (N) and verapamil SR (V) on blood pressure (BP) control and exercise performance. After a 2-week placebo phase, all subjects had measurements of VO2max, maximal workload, and endurance time. They were then randomized to either N (30 to 90 mg/day) or V (240 to 480 mg/day) and retested when BPs had stabilized. At rest, N lowered systolic (S) BP by 12 mm Hg (P = .02 compared to baseline) and diastolic (D) BP by 11 mm Hg (P = .001). V lowered SBP by 8 mm Hg (P = .013) and DBP by 11 mm Hg (P = .002). Neither drug affected resting heart rate. V significantly decreased resting epinephrine (P = .05) and there was a tendency for V to reduce norepinephrine (P = .07) and dopamine (P = .08). N tended to increase plasma renin activity (P = .07). During graded cycle ergometry N, compared with placebo, significantly lowered DBP at all exercise levels (P = .011), but had no significant effect on heart rate (HR), SBP, or heart rate pressure product (HRPP). Pulse pressure (PP) was significantly increased (P = .045), which was most noticeable at high exercise levels. Compared with placebo, V caused a marked reduction of exercise HR (P < .001), which was more pronounced at high levels, SBP (P = .004), DBP (P = .004), mean arterial pressure (MAP) (P = .001), and HRPP (P < .001).(ABSTRACT TRUNCATED AT 250 WORDS)
Serum electrolyte levels by themselves may be difficult to interpret. For example, an abnormal serum potassium concentration cannot be understood without taking into account the patient's history, other serum electrolyte values, and possibly results of other laboratory tests. Knowledge of the principles of serum electrolyte concentrations, therefore, is an important adjuvant to understanding their implications.
The authors administered a personality inventory, the Eysenck Personality Inventory and a distress scale, the Symptom Questionnaire, to all patients in a walk-in clinic of a general hospital during an influenza epidemic. Hostility, depression, anxiety and somatic symptoms were significantly higher in patients with upper respiratory tract infections (p less than .005); the majority scored in the range of psychiatric patients, regardless of whether patients had clinically classical influenza or merely symptoms and signs of another respiratory tract infection. There were no differences in the personality traits of extraversion or neuroticism between any of the groups, suggesting that hostility and distress were consequences of the viral infections and were largely unaffected by preexisting personality traits.
The aim of this study was to look at changes in peak expiratory flow rates (PEFR) prior to emergency department visits for decompensated chronic obstructive pulmonary disease (COPD). It was designed as a prospective, double-blind study at the Albuquerque Veterans Affairs Medical Center. Twelve patients with an irreversible component of airflow obstruction on pulmonary function tests were assessed. At entry, all subjects were instructed in the use of a mini-Wright peak flow meter with electronic data storage. They then entered a 6-month monitoring phase in which they recorded PEFR twice daily, before and after bronchodilators. The meter displays were disabled so that the patients and their physicians were blinded to all values. Medical care was provided in the customary manner. Patients were considered to have respiratory decompensation if they required treatment for airflow obstruction in the Emergency Department (ED) and no other causes of dyspnea could be identified. Simple linear regression was used to model changes in PEFR over time. The 12 subjects had 22 episodes of respiratory decompensation during 1741 patient-days of observation. Two episodes could not be analysed because of missing values. Ten episodes in seven subjects were characterized by a significant linear decline in at least one peak flow parameter prior to presentation. The mean rates of change for the four daily parameters varied from 0.22% to 0.27% predicted per day (or 1.19 to 1.44 1 min-1 day-1). The average decrement in these parameters ranged from 30.0 to 33.8 1 min-1 (or 18.6%-25.9% of their baseline values). No temporal trends were found for the 10 episodes occurring in the other five subjects. We concluded that respiratory decompensation is characterized by a gradual decline in PEFR in about half of cases. Future studies should be done to elucidate the mechanisms of respiratory distress in the other cases.
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