concept

Respiratory alkalosis

The state where blood turns alkaline because carbon dioxide is leaving faster than the body makes it - from over-breathing, or from being moved into air far poorer in carbon dioxide than the one the body was calibrated for. The bicarbonate pool cannot shrink to match: the kidney needs days to shed it, while the gas washes out in tens of seconds. The consequences are not gentle: cerebral arterioles constrict and cause syncope, ionised calcium binds to plasma proteins and produces tetany and laryngeal spasm, and the loss of proton drive at the respiratory centre can stop breathing altogether.