Acute respiratory acidosis does not increase plasma potassium in normokalaemic anaesthetized patients. A controlled randomized trial.
OBJECTIVE
Few and conflicting data are available regarding the changes of plasma potassium concentration during acute respiratory acidosis in human beings. This study compares the acute changes in plasma potassium concentration in acutely hypercapnic patients and in non-hypercapnic patients during general anaesthesia.


METHODS
Thirty-three patients undergoing interventional rigid bronchoscopy were studied. Ventilation of the lungs was randomly conducted using either spontaneous-assisted ventilation or intermittent negative-pressure ventilation. All patients received the same anaesthetic protocol. Arterial blood gases and osmolality, and plasma concentrations of glucose, sodium, potassium and chloride were measured.


RESULTS
Intraoperatively, PaCO2 was higher during spontaneous-assisted ventilation than during intermittent negative-pressure ventilation (9 +/- 1.8 vs. 5.4 +/- 1.2 kPa, P < 0.001) and the pH was also lower during spontaneous-assisted ventilation than during intermittent negative-pressure ventilation (7.24 +/- 0.07 vs. 7.4 +/- 0.08, P < 0.001). Plasma potassium concentration remained similar in both groups (3.8 +/- 0.2 mmol L(-1) with spontaneous-assisted ventilation vs. 3.7 +/- 0.4 mmol L(-1) with intermittent negative-pressure ventilation).


CONCLUSIONS
Acute respiratory acidosis does not affect plasma potassium concentration.
Natalini
G
G
Department of Anaesthesia and Intensive Care, Spedali Civili Hospital, Brescia, Italy.
Seramondi
V
V
Fassini
P
P
Foccoli
P
P
Toninelli
C
C
Cavaliere
S
S
Candiani
A
A
D000142:Acidosis, Respiratory / Q000097:blood*; D000208:Acute Disease; D000768:Anesthesia, General; D001784:Blood Gas Analysis; D001999:Bronchoscopy; D002245:Carbon Dioxide / Q000097:blood; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000097:blood; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000097:blood*; D012121:Respiration, Artificial; D015919:Ventilators, Negative-Pressure
D002245:Carbon Dioxide; D011188:Potassium