Cardiovascular response during severe acute asthma and its treatment in children.

Heart rate, blood pressure, pulsus paradoxus, and cardiac output measured by means of transthoracic electrical impedance cardiography have been recorded in 29 children mean age 10 years +/- 2 SD during status asthmaticus. Changes were recorded over the first two hours of treatment during which all patients received oxygen, intravenous fluid, and hydrocortisone, and were randomly assigned to receive aminophylline, salbutamol, or both. Admission values showed significant correlation of pulsus paradoxus with PaCO2 (r = 0.66). Pulsus paradoxus was greater than 20 mmHg for all patients with PaCO2 above 5.5 kPa. Mean stroke volume and cardiac output were 89% and 131% of the resting convalescent values in the same children. Stroke volume cardiac output and heart rate did not correlate with peak expiratory flow rate or blood gas measurements. Aminophylline and salbutamol together were associated with significantly greater increase in PEF than aminophylline alone (P less than 0.05). Nebulised salbutamol was just as effective as intravenous salbutamol. Heart rate and systolic blood pressure declined significantly after nebulised salbutamol and aminophylline, but not after intravenous salbutamol and aminophylline. Stroke volume and cardiac output did not change significantly in any treatment group.