Biphasic carbon dioxide waveform in severe kyphoscoliosis

 

Carbon dioxide waveform recorded in a patient with severe kypho-scoliosis. The CO₂ waveform has two humps. Kyphoscoliosis resulted in a compression of the right lung. The compressed right lung had a relatively high airway resistance, was poorly ventilated, and was relatively hypercapnic, whereas the left lung had a relatively low airway resistance, was hyperventilated, and was relatively hypocapnic. Under these circumstances, relatively hypocapnic gas from well ventilated, low airway resistance lung reached the CO₂ analyzer first causing first distinct low peak, and relatively hypercapnic gas from poorly ventilated, high airway resistance lung reached the CO₂ analyzer last causing second distinct high peak.

Reference :

Nichols K, Benumof, JL. Biphasic carbon dioxide excretion from a patient with severe kyphoscoliosis. Anesthesiology 1989;71:986-7 (with permission).