a. Use the provided spirometry test results in Table 1 to calculate the change in pre- vs post- bronchodilator function for FEV1, FVC, and FEV1/FVC ratio. Present your results in a table with both as values in litres and as percent-change b. What do the above values tell you about LF’s condition? c. Using your knowledge of respiratory physiology, describe how use of a bronchodilator explains the test results observed.
LF, a 34 year old white male, presented to the emergency room complaining of acute and severe shortness
of breath and intense chest tightness. LF’s speech was choppy and breathing was very rapid and erratic,
punctuated by noticeable wheezing. LF’s medical records included the results of pulmonary function
testing he had undergone six months before (Table 1).
Table 1. Pre- vs post-bronchodilator spirometry at baseline
Pre-Bronchodilator (L) Post-Bronchodilator (L) Predicted Normal (L)
FEV1 3.22 4.25 5.55
FVC 5.20 5.52 6.51
His medical records also indicated prior admission for respiratory symptoms and a history of poorly-
controlled asthma. Blood gas tests were performed shortly after LF was admitted (Table 2) and a PEFR
(peak expiratory flow rate) test performed. The latter revealed a PEFR of 181 L/min (normal: 525 L/min).
LF additionally had serum creatinine measured at admission and at 12h post-admission (Table 3).
Table 2. Blood gas values upon admission
Admission + 2h +4h +6h +8h +10h +12h
PaO2 (mmHg) 65 65 66 66 66 68 70
PaCO2 (mmHg) 32 34 35 36 37 38 40
HCO3- 27 27 27 25 25 24 24
pH 7.52 7.52 7.51 7.51 7.49 7.48 7.47
SpO2 (%) 89 90 90 91 92 93 94
Table 3. Serum creatinine values at admission and after 12h
Admission + 12h
SCR(mg/dL) 1.55 1.42
LF received high-dose bronchodilator medication through use of a valved holding chamber. This was
followed by intravenous glucocorticoids and nebulized bronchodilators every two hours for a twelve-hour
period, followed by nebulized bronchodilators every four hours for a forty-eight hour period.
After discharge from the hospital, LF was provided a take-home flow meter to monitor his lung function.
Table 4 shows LF’s PEFR results during a 30-day period.
Table 4. Peak flow monitoring from day 1-30 post-discharge. All PEFR values are given in L/min.
Day PEFR Day PEFR Day PEFR Day PEFR Day PEFR Day PEFR
1 495 6 500 11 493 16 503 21 453 26 483
2 490 7 493 12 483 17 276 22 468 27 500
3 500 8 510 13 479 18 255 23 492 28 496
4 478 9 483 14 488 19 277 24 493 29 488
5 486 10 492 15 491 20 379 25 487 30 489
Questions
a. Use the provided spirometry test results in Table 1 to calculate the change in pre- vs post-
bronchodilator function for FEV1, FVC, and FEV1/FVC ratio. Present your results in a table with both as
values in litres and as percent-change
b. What do the above values tell you about LF’s condition?
c. Using your knowledge of respiratory physiology, describe how use of a bronchodilator
explains the test results observed.
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