Lancet
-
Comparative Study Clinical Trial Controlled Clinical Trial
Inaccuracy of the Hawksley random zero sphygmomanometer.
To examine the accuracy of the Hawksley random zero sphygmomanometer two studies were done with subjects with a wide range of blood pressure. When readings made by one observer on the UK model of the Hawksley sphygmomanometer were compared with readings by two independent observers on separate mercury sphygmomanometers, the Hawksley device underestimated systolic readings by a mean (SD) of 2.0 (2.4) and 0.5 (3.6) mm Hg and diastolic readings by a mean of 3.7 (2.7) and 2.8 (2.9) mm Hg. ⋯ Thus, the quantitative aspects of blood pressure in epidemiological and intervention studies in which the Hawksley random zero sphygmomanometer was used need re-evaluation. Moreover, the Hawksley random zero sphygmomanometer, in its present design, should not be used in hypertension research.
-
Randomized Controlled Trial Comparative Study Clinical Trial
Bronchodilator, cardiovascular, and hypokalaemic effects of fenoterol, salbutamol, and terbutaline in asthma.
The airway response and cardiovascular and hypokalaemic effects of fenoterol, salbutamol, and terbutaline given in multiples of standard doses from metered-dose inhalers were studied in ten patients with mild asthma. In a double-blind, crossover, placebo-controlled study the subjects received 2, 6, and 18 puffs of each drug with intervals of 90 min, and forced expiratory volume in 1 s, heart rate, QTc interval, plasma potassium concentration, tremor, and bronchial reactivity to histamine were measured. All three drugs produced similar bronchodilatation. ⋯ Fenoterol afforded no additional protection against histamine compared with salbutamol. These findings suggest that at doses based on those used in clinical practice fenoterol causes more adverse effects than salbutamol or terbutaline. The most likely explanation for these effects is that fenoterol has been marketed at a higher dose than the other beta 2-agonists; fenoterol may in addition be less selective for beta 2 receptors.