[The effect of short-term hyperventilation on the concentration of ionized serum calcium].
OBJECTIVE
Paraesthesias and carpopedal spasms on hyperventilation are explained by a reduction in ionised serum calcium (ISC). We tested whether 5-minute hyperventilation changes the concentration of ISC.


METHODS
Arterial blood samples were obtained via a small plastic catheter introduced into the femoral artery of ten healthy male volunteers (mean age 33 years) before, during and after 5 minutes of hyperventilation, which was achieved by deep and rapid breathing and considered adequate when the end-expiratory pCO2 had fallen to 2.5 kPA within the first minute and remained below this level during the remaining 4 minutes. These criteria were met in nine of the ten patients. The ISC concentration was measured with an ion-selective electrode, the pH, paCO2 and bicarbonate levels with an autoanalyser.


RESULTS
Paraesthesias of the fingers and hand occurred in nine of the volunteers, carpopedal spasms in seven. Despite a definite rise in pH from 7.39 +/- 0.02 to 7.75 +/- 0.045, the concentration of ISC did not change significantly during the hyperventilation.


CONCLUSIONS
Paraesthesias and carpopedal spasms which occur during hyperventilation are not caused by a fall in ionised serum calcium in arterial blood.
Steurer
J
J
Medizinische Poliklinik, Departement für Innere Medizin, Zürich.
Pei
P
P
Vetter
W
W
D000328:Adult; D001639:Bicarbonates / Q000097:blood; D002118:Calcium / Q000097:blood*; D002245:Carbon Dioxide / Q000097:blood; D005528:Foot; D006225:Hand; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006985:Hyperventilation / Q000097:blood* / Q000150:complications; D007477:Ions; D008297:Male; D010292:Paresthesia / Q000097:blood / Q000209:etiology; D010313:Partial Pressure; D012016:Reference Values; D013035:Spasm / Q000097:blood / Q000209:etiology; D013997:Time Factors
D001639:Bicarbonates; D007477:Ions; D002245:Carbon Dioxide; D002118:Calcium