Bedside spirometry will be performed using a handheld spirometer, and the following parameters will be recorded: forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), FEV1/FVC ratio , forced expiratory flow in the middle 25 to 75% of flow (FEF25-75%), inspiratory capacity (IC), and peak expiratory flow rate (PEFR). A subsequent full set of pulmonary function tests will be obtained in the recovery phase on day 35 using a hand held spirometer and body plethysmography. This will include FEV1 , FVC, FEV1/FVC, FEF25-75%, IC, PEFR, total lung capacity (TLC), residual volume (RV), and diffusing capacity of carbon monoxide (DLCO).