Question

Mike is sitting in hisathletic training suite feeling sorry for himself. He moved fromSouthern California to play soccer at Northern Minnesota University(NMU) as a highly recruited player. All was well until he got sickwith a miserable cold. He soon recovered, but now he finds himselfwith a lingering dry cough and difficulty catching his breath anytime he exerts himself, which is every day! He also notices it hasgotten worse as the weather has become colder. To make thingsworse, Mike feels, and looks, like he's out of shape, so his coachhas been criticizing him for dogging it. A few days later, Mikerelays his story to JP, the head athletic trainer at NMU. "I'mthinking my cold is coming back, or something else is wrong withme. When I'm just hanging out, like now, I feel fine. But as soonas I start to run I get winded and can't stop coughing." JP listensto Mike's breathing sounds with his stethoscope, but hears nothingabnormal. So he tells Mike to come back as soon as the symptomsreturn during soccer practice. Twenty minutes later, Mike is backin the athletic training suite, audibly wheezing, coughing, andshort of breath. The team physician, Dr. McInnis, happens to bethere and performs a complete physical exam. He also does pulmonaryfunction tests with Mike using spirometry, including a forced vitalcapacity (FVC) and forced expiratory volume in one second (FEV1).He instructs Mike to take a maximal inhalation and then exhale asforcefully and maximally as possible into the spirometer. Based onhis findings, Dr. McInnis tells Mike he thinks he is experiencingcold-induced bronchoconstriction (also called cold-induced asthma),which is made worse by exertion. The doctor explains to Mike thathis recent upper respiratory infection probably inflamed hisairways, making them hypersensitive and reactive to irritants, suchas cold and physical exertion. When Mike exercises in the cold,autumn afternoons of Minnesota, his sensitive airways temporarilybronchoconstrict, causing the symptoms he is experiencing. Asthmais almost always a reversible condition. Dr. McInnis prescribes twopuffs of an albuterol inhaler, to be used 10 minutes before a boutof exercise in the cold.

What must happen to Mike's intrapulmonarypressure in order for him to maintain normal air flow duringinhalation and exhalation when he is having one of his asthmaattacks?