Respiratory countermaneuvers in autonomic failure.
BACKGROUND
Selective increase of inspiratory impedance augments blood pressure in healthy subjects through activation of the respiratory pump. We studied the efficacy of respiratory maneuvers to reduce orthostatic hypotension in autonomic failure.


METHODS
Mean arterial pressure (MAP) after standing up was recorded in 10 patients in five conditions: normal standing, leg muscle tensing, inspiratory pursed lips breathing, inspiratory sniffing, and a device causing inspiratory obstruction.


RESULTS
The maneuvers caused significant differences in standing MAP. Inspiratory obstruction and leg muscle tensing increased MAP to a comparable degree. The effect of inspiratory pursed lips breathing and inspiratory sniffing depended on concomitant hyperventilation.


CONCLUSIONS
Respiratory maneuvers reduce orthostatic hypotension in autonomic failure through activation of the respiratory pump, provided hyperventilation is avoided.
Thijs
Roland D
RD
Department of Neurology and Clinical Neurophysiology, Leiden University Medical Centre, Leiden, the Netherlands. r.d.thijs@lumc.nl
Wieling
Wouter
W
van den Aardweg
Joost G
JG
van Dijk
J Gert
JG
D000368:Aged; D001342:Autonomic Nervous System Diseases / Q000150:complications* / Q000503:physiopathology; D001783:Blood Flow Velocity; D001794:Blood Pressure; D001945:Breathing Exercises; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D007024:Hypotension, Orthostatic / Q000209:etiology / Q000517:prevention & control*; D001239:Inhalation; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000503:physiopathology; D009119:Muscle Contraction; D011187:Posture; D012119:Respiration; D012138:Respiratory Therapy / Q000295:instrumentation; D014939:Work of Breathing