The acute effects of inhaled salbutamol on the beat-to-beat variability of heart rate and blood pressure assessed by spectral analysis.
OBJECTIVE
We wanted to study the effects of a 600 micrograms inhaled salbutamol dose on the cardiovascular and respiratory autonomic nervous regulation in eight children suffering from bronchial asthma.


METHODS
In this randomized, double-blind, placebo-controlled, crossover study we continuously measured electrocardiogram, finger systolic arterial pressure (SAP) and flow-volume spirometry at baseline as well as 20 min and 2 h after the drug inhalation. The R-R interval (the time between successive heart beats) and SAP variabilities were assessed by using spectral analysis. Baroreflex sensitivity was assessed by using cross-spectral analysis.


RESULTS
Salbutamol significantly decreased the total and low frequency (LF) variability of R-R intervals as well as the high frequency (HF) variability of R-R intervals and of SAP. Salbutamol significantly increased the LF/HF ratio of R-R intervals and of SAP, minute ventilation, heart rate and forced pulmonary function in comparison with placebo. The weight of the subjects significantly correlated positively with baroreflex sensitivity and negatively with heart rate after the salbutamol inhalation.


CONCLUSIONS
We conclude that the acute salbutamol inhalation decreases cardiovagal nervous responsiveness, increases sympathetic dominance in the cardiovascular autonomic balance, and has a tendency to decrease baroreflex sensitivity in addition to improved pulmonary function.
Jartti
T
T
Department of Paediatrics, Turku University Hospital, Finland.
Kaila
T
T
Tahvanainen
K
K
Kuusela
T
T
Vanto
T
T
Välimäki
I
I
D000280:Administration, Inhalation; D000318:Adrenergic beta-Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D000420:Albuterol / Q000008:administration & dosage / Q000494:pharmacology*; D017704:Baroreflex / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects*; D001993:Bronchodilator Agents / Q000008:administration & dosage / Q000494:pharmacology*; D002000:Bronchospirometry; D002648:Child; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004562:Electrocardiography / Q000187:drug effects; D005260:Female; D005387:Finland; D005540:Forced Expiratory Flow Rates / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008297:Male; D012129:Respiratory Function Tests; D016683:Supine Position
D000318:Adrenergic beta-Agonists; D001993:Bronchodilator Agents; D000420:Albuterol