Respiratory muscle strength and lung function in patients undergoing medical thoracoscopy.

BACKGROUND Medical thoracoscopy (MT) is a procedure considered as minimally invasive. The safety of the procedure has been questioned recently in fragile patients, but no explanation of the pathophysiologic mechanism has been given. Although MT is applied by respiratory physicians who are also dealing with patients with impairment of lung function, it is surprising that there are no data concerning lung mechanics and function in this patient population. OBJECTIVES To assess respiratory muscle strength and lung function in patients undergoing MT, with or without talc pleurodesis. METHODS We measured prospectively the maximal inspiratory (MIP) and expiratory pressures (MEP) and lung function of 29 patients who underwent MT before (baseline) and on consecutive days following MT. RESULTS 29 patients participated with a mean age of 63.6 +/- 13.8 (range 20-79) years. 15 of them underwent talc pleurodesis and 14 diagnostic thoracoscopy. Mean MIP and MEP values were significantly decreased on day (d) 1 after MT compared to baseline (p = 0.03 and p = 0.007, respectively) and recovered on d2. FEV(1) and FVC mean values were also found significantly decreased on d1 after MT compared to baseline (p < 0.0001 and p = 0.0003, respectively) and recovered on d2. Patients with pleurodesis presented with lower mean values of the studied parameters than those with diagnostic thoracoscopy. No significant complication was associated with the procedure. CONCLUSION Respiratory muscles and lung function can be temporarily affected from MT. Physicians should be alert, especially in patients with already impaired lung function, where any further impairment could be detrimental.