Methods and clinical significance of studying chemical drives

Studying chemical control of ventilation implies evaluation of both chemore ceptor functions taken into account however the mechanical factors in influ encing the effector organs. The role of abnormal chemical drives has been d emonstrated in COPD patients. More recently the role of abnormal chemical d rives was studied during sleep. Absent or severely depressed drives may fac ilitate the development of central apneas and hypoventilation. High drives may lead to periodic breathing eventually with central apneas as well. Most intriguing therefore is the role of chemical drives in the pathogenesis of the obstructive and central sleep apnea syndrome. There is accumulating ev idence that fluctuations in the drive to breathe may adversely affect the u pper airway patency and facilitate upper airway closure and obstructive apn eas. Interaction with chemical drives (eg by administration of acetazolamid e) has been shown to improve central (and eventually also obstructive) slee p apnea. Studying chemical drives will probably be clinically useful in sol ving the complex mechanisms controlling ventilation during sleep in patient s with and without underlying airway or lung disease. (C) 1998 Elsevier Sci ence B.V. All rights reserved.