Comparing high and low levels of continuous positive airway pressure on lung aeration in patients with pleural drainage: A feasibility study for a randomized controlled trial

Abstract

Objective:We explored the feasibility of use of continuous positive airway pressure (CPAP) with 15-and 4-cmH 2 O for a randomized controlled trial with patients with pleural drainage.Methods: Ten patients with traumatic pleural effusion drained within 24 hr, with controlled pain received randomly CPAP with 0-, 4-, and 15-cmH 2 O. Computed tomography was used to assess the lung aeration. Patients reported the level of tolerability. Air leak was also observed as a parameter of safety. The levels of pressure were compared using the Friedman test followed by the Tukey test as post hoc. Results:The lung area under CPAP with 15 cmH 2 O (median = 3,913 mm 2 ; IQR = 3,416-4,390 mm 2 ) was greater than 4 (median = 3,495 mm 2 ; IQR = 3,075-3,954 mm 2 ) and 0 cmH 2 O (median = 3,382 mm 2 ; IQR = 2,962-3,658 mm 2 ; p < 0.001). There was no difference between lung areas under CPAP with 4 and 0 cmH 2 O. All levels of pressure were well tolerated by patients. No air leak was observed during the assessments.Conclusion: CPAP with 15 cmH 2 O is able to expand lungs of patients with pleural drainage. CPAP with 4 cmH 2 O seems not have therapeutic effect. In addition, CPAP with 15 cmH 2 O is well tolerated and safe in this population. KEYWORDScontinuous positive airway pressure, computerized tomography, pleural effusion, thoracic surgery

Continuous positive airway pressure after major abdominal surgery: an independent discussion of the Prevention of Respiratory Insufficiency after Surgical Management trial

“…CPAP improved atelectasis in only 40% of patients after cardiac surgery. 22 The level of CPAP support is also important, 23 although higher CPAP (40 cm H 2 O) failed to increase lung volume in acute respiratory distress syndrome (ARDS), 24 perhaps because CPAP is less effective in improving aeration of lung areas with diffuse injury compared with focal changes. 25 In chronic obstructive pulmonary disease (COPD), lower CPAP (5 cm H 2 O) failed to increase lung aeration, whereas 10e15 cm H 2 O increased emphysematous regions.…”