Normalizing CO2 in chronic hyperventilation by means of a novel breathing mask: a pilot study.
BACKGROUND
Chronic idiopathic hyperventilation (CIH) is a form of dysfunctional breathing that has proven hard to treat effectively.


OBJECTIVE
To perform a preliminary test of the hypothesis that by periodically inducing normocapnia over several weeks, it would be possible to raise the normal resting level of CO2 and achieve a reduction of symptoms.


METHODS
Six CIH patients were treated 2 h a day for 4 weeks with a novel breathing mask. The mask was used to induce normocapnia in these chronically hypocapnic patients. Capillary blood gases and acid/base parameters [capillary CO2 tension (PcapCO2 ), pH, and standard base excess (SBE)] were measured at baseline and once each week at least 3 h after mask use, as well as spirometric values, breath-holding tolerance and hyperventilation symptoms as per the Nijmegen Questionnaire (NQ).


RESULTS
The mask treatment resulted in a significant increase of resting PcapCO2 (+0.45 kPa, P = 0.028), a moderate increase in SBE (+1.4 mEq/L, P = 0.035) and a small reduction in daily symptoms (-3.8 NQ units, P = 0.046). The effect was most pronounced in the first 2 weeks of treatment.


CONCLUSIONS
By inducing normocapnia with the breathing mask 2 h a day for 4 weeks, the normal resting CO2 and acid/base levels in chronically hyperventilating patients were partially corrected, and symptoms were reduced.
Department of Respiratory Diseases, Aarhus University Hospital, Aarhus C, Denmark.
Troels
T
Johansen
Sandy
S
Jack
Ronald
R
Dahl
D000136:Acid-Base Equilibrium / Q000502:physiology; D000142:Acidosis, Respiratory / Q000378:metabolism / Q000628:therapy*; D000208:Acute Disease; D000328:Adult; D000472:Alkalosis, Respiratory / Q000378:metabolism / Q000628:therapy*; D002196:Capillaries / Q000378:metabolism; D002245:Carbon Dioxide / Q000097:blood*; D002908:Chronic Disease; D004867:Equipment Design; D005260:Female; D006801:Humans; D006985:Hyperventilation / Q000378:metabolism / Q000628:therapy*; D016857:Hypocapnia / Q000378:metabolism / Q000628:therapy*; D008297:Male; D008397:Masks; D008875:Middle Aged; D010865:Pilot Projects; D016896:Treatment Outcome; D055815:Young Adult
D002245:Carbon Dioxide
breathing mask; dysfunctional breathing; hyperventilation; hypocapnia; rebreathing; respiratory acidosis; respiratory alkalosis