Do simple beside lung function tests predict morbidity after rib fractures?

Abstract

Background We evaluated if incentive spirometry volume (ISV) and peak expiratory flow rate (PEFR) could predict acute respiratory failure (ARF) in patients with rib fractures. Methods Normotensive, co-operative patients were enrolled prospectively. ISV and PEFR were measured on admission, at 24 h and at 48 h by taking the best of three readings each time. The primary outcome, ARF, was defined as requiring invasive or noninvasive positive pressure ventilation. Results 99 patients were enrolled (median age, 77 years). ARF occurred in 9%. Of the lung function tests, only a low median ISV at admission was associated with ARF (500 ml vs 1250 ml, p = 0.04). Three of 69 patients with ISV of ≥1000 ml versus six of 30 with ISV <1000 ml developed ARF (p = 0.01). Other significant factors were: number of rib fractures, tube thoracostomy, any lower-third rib fracture, flail segment. Conclusion PEFR did not predict ARF. Admission ISV may have value in predicting ARF.