Hyperventilation syndrome

In psychiatry, hyperventilation syndrome (HVS) is an episodic disorder that often presents with chest pain and a tingling sensation of the fingertips (paresthesia) and around the mouth, as well as deep and labored breathing (causing hyperventilation), although chronic but subtle hyperventilation can cause these symptoms too.

HVS can be part of a panic attack but, despite all the stigma, most patients are not putting on a show but are in true distress. The hyperventilation is self-promulgating as carbon dioxide () levels fall and respiratory alkalosis (high blood pH) develop. The respiratory alkalosis leads to changes in the way the nervous system fires and leads to the paresthesiae, dizziness and perceptual changes that often accompany this condition.

A rapid traditional intervention is to make the patient breathe into a paper bag, causing rebreathing and restoration of CO₂ levels. The same benefits can be obtained from deliberately slowing down the breathing rate by counting or looking at a watch.