Respiratory Muscle Strength and Lung Function in Patients Undergoing Medical Thoracoscopy

Abstract

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. FEV₁ 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.

Mechanisms of Pleurodesis

“…Thoracoscopy is associated with a transient impairment in lung function, which is more pronounced when pleurodesis is performed [46]. With the exception of some complications related to the technique itself [47], which could be prevented using ultrasound examination, the most relevant are systemic complications associated with intrapleural instillation of the sclerosant.…”

Temporal evolution of thoracocentesis-induced changes in spirometry and respiratory muscle pressures

“…The interpretation we postulate to hold true is the following: group B had a large effusion volume compressing a large part of ipsilateral lung having remained atelectatic for a certain time period. When decompressed after fluid removal (T2), the dysfunctional surfactant due to previous atelectasis resulted in an elevation of the diaphragm and alteration of its length-tension property, thus generating lower MIPs 34 35 Froudarakis et al ,36 who had studied patients undergoing medical thoracoscopy for large pleural effusions, had also found decreased MIP the day after the procedure, which was gradually restored during the following days.…”

Development of an Electronic Manometer for Intrapleural Pressure Monitoring

“…There might be other clinical and research applications of pleural pressure measurement. For example, Froudarakis et al [18 ]have recently shown that respiratory muscle strength and lung function can be temporarily impaired after medical thoracoscopy. According to our studies, pleural pressure measurements before and after the procedure may add new information on the mechanisms of this phenomenon.…”