 More and more people across the globe are suffering from airway diseases like asthma and chronic obstructive pulmonary disease or COPD. If these patients need surgery requiring general anesthesia, their airway disease can complicate the process and change how quickly anesthesia takes effect and wears off. One common issue is that these patients experience what is called ventilation-perfusion mismatch where some lung regions may get enough air but not enough blood flow or vice versa. When this happens, it can change how the body processes different types of anesthetics, but so far the details aren't clear. Now a study has investigated whether anesthetic solubility, how easily the drug dissolves in blood, is important. In the study, an international group of anesthesiologists evaluated two inhalational anesthetics in pigs using a drug called methicoline to constrict the airways and mimic the airway disease of an asthmatic or someone with COPD. The team tested desflurane, a volatile anesthetic with very low solubility, and isoflurane, which is more soluble. They measured the uptake and elimination of each drug before and during bronchoconstriction, using micropore membrane inlet mass spectrometry. In this technique, the amount of anesthetic can be evaluated accurately and quickly with mass spectrometry using a small blood sample. The group found that both drugs were slower to be taken up and eliminated in pigs when their airways were constricted, but the effect was more severe with desflurane. For example, while peak uptake fell by less than a quarter in the isoflurane group, it dropped almost a half in the desflurane group. Similarly, elimination fell by just 8% in the pigs given isoflurane, versus 46% in those given desflurane. The results still need to be confirmed in humans, but they suggest that less soluble drugs like desflurane are more affected by ventilation-perfusion scatter, as can be seen in asthma or COPD. Such scattering slows down the onset of anesthesia, as well as the recovery from it, offsetting some of the advantages modern, low-solubility anesthetics have.