It is well-known that minute ventilation and carbon monoxide level are inversely related. Higher minute ventilation leads to lower CO2. What many need to appreciate is that the relationship is not linear. The magnitude of the effect of minute ventilation on CO2 is different in different CO2 ranges. Around normal CO2 of about 40 mmHg, significant changes in minute ventilation bring about a very modest alteration of CO2 level. Consequently, in a healthy individual, the CO2 level remains stable despite hyper or hypoventilation.
The relationship is entirely different around high CO2 levels, where minimal minute ventilation changes can drastically affect CO2.
This is precisely why patients with chronic hypercarbia can quickly go from CO2 of 60 to CO2 of 120 due to a mucus plug or a Benadryl pill. This is also why noninvasive ventilation (NIV), which is not that powerful, can bring CO2 levels in those patients back to the baseline.