Background: Patients with idiopathic pulmonary fibrosis (IPF) usually presented with exercise induced oxygen desaturation (EID). We hypothesize that pulmonary function tests (PFTs), pulmonary haemodynamics, and gasometric parameters may contribute to EID. Objective: This randomized, double blind, prospective study was conducted to evaluate different parameters that may contribute to EID in IPF. Patients and methods: Thirty five patients with stable IPF were enrolled in this study. Resting PFTs, arterial blood gases, echocardiography, and incremental cardiopulmonary exercise testing (CPET) were done for all patients. Desaturated patients (DS) were those with reduced oxygen saturation ≥ 4 in comparison to resting value and post exercise SaO 2 ≤ 88%, the remaining patients were considered non desaturated (NDS) group. Results: EID was observed in 17 patients (DS). forced expiratory volume in 1 second (FEV 1 %), forced vital Capacity (FVC%) & Diffusion lung capacity (DLCO) were significantly lower in DS group compared to NDS group (P = 0.02, P = 0.004 & P = 0.01 respectively). Resting oxygen saturation was significantly lower in DS group (P = 0.018) however, resting partial arterial carbon dioxide pressuer(PaCO 2 ) and mean pulmonary artery pressure (mPAP) were significantly higher in DS group (P = 0.004 & P = 0.006). Using ROC curve, the sensitivity of resting SaO 2 ≤ 92, 9%, DLCO ≤ 25% and mPAP≥ 25 were 62.5%, 50% & 88.9%, respectively, and specificity were 84.2%, 100% & 78.5 % respectively for predicting EID in IPF. Conclusion: exercise induced oxygen desaturation in IPF can be predicted from PFTs and haemogasometric parameters.
Hamdy et al. (Mon,) studied this question.