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.