Pleural Manometry in Pneumothorax: Evaluating Tension Physiology and Predicting Outcomes.

Abstract

Tension pneumothorax (TP) traditionally is defined pleural pressure (P_pl) exceeding atmospheric pressure, which reduces venous return and leads to hemodynamic collapse. However, P_pl has yet to be measured directly in TP because of technical limitations, nor has it been studied in predicting outcomes for pneumothorax. Do increased pleural pressures increase the risk of TP and are they associated with pleurodesis or death? In this multicenter, prospective, observational study, participants with newly diagnosed pneumothorax (tension and nontension) were recruited. P_pl throughout the respiratory cycle was measured at the time of chest thoracostomy, and patients were followed up for outcomes of pleurodesis and death during hospitalization. At 5 centers, 37 patients with a pneumothorax (9 tension, 28 nontension) were enrolled. Seventy-three percent of recruited patients had an iatrogenic pneumothorax. Both increased inspiratory P_pl (OR, 1.40; 95% CI, 1.10-1.76) and expiratory P_pl (OR, 1.22; 95% CI, 1.05-1.42) were associated with increased risk of tension. A subset of patients without tension were found to have supraatmospheric P_pl. Lower inspiratory P_pl also was associated with an increased risk of pleurodesis (OR, 0.66; 95% CI, 0.45-0.96). Our results show that measurement of P_pl in TP is feasible. Elevated P_pl alone may not dictate the development of TP. In this small study, with most participants demonstrating iatrogenic pneumothorax, an association between P_pl and need for pleurodesis was found that may be a useful predictive tool to guide earlier definitive management. These findings should be explored further in other causes of pneumothorax as well. ClinicalTrials.gov; No.: NCT04630301; URL: www. gov.