Final answer:
During an acute asthma attack, the patient's spirogram shows a decreased FEV1 due to airway obstruction. Asthma increases airway resistance, thus causing a lower FEV1/FVC ratio, which is indicative of an obstructive lung disease.
Step-by-step explanation:
The lung values that changed in the spirogram of a patient experiencing an acute asthma attack were a decrease in the forced expiratory volume in one second (FEV1) due to airway obstruction, making option B the correct answer. This is because asthma causes an increase in resistance within the airways, making it more difficult to expel air, which leads to a lower FEV1 value. The forced vital capacity (FVC) can also decrease, but it is the disproportionate reduction in FEV1 that is most illustrative of asthma during an attack. The FEV1/FVC ratio subsequently decreases, as it reflects the reduction in airflow and the obstruction present in the airways.
When a patient has asthma, breathing and gas exchange are altered due to increased resistance in the lungs. The increased resistance causes airway obstruction, trapping air in the lungs and causing breathing to become more difficult. This obstruction can be detected through spirometry, as it will reveal lowered FEV1 values and a lowered FEV1/FVC ratio, which are indicative of obstructive lung disease.