Lateral position during severe mono-lateral pneumonia: an experimental study

Abstract

Patients with mono-lateral pneumonia and severe respiratory failure can be positioned in lateral decubitus, with the healthy lung dependent, to improve ventilation-perfusion coupling. Oxygenation response to this manoeuvre is heterogeneous and derecruitment of dependent lung has not been elucidated. Nine pigs (32.2 ± 1.2 kg) were sedated and mechanically ventilated. Mono-lateral right-sided pneumonia was induced with intrabronchial challenge of Pseudomonas aeruginosa. After 24 h, lungs were recruited and the animals were randomly positioned on right or left side. After 3 h of lateral positioning, the animals were placed supine; another recruitment manoeuvre was performed, and the effects of contralateral decubitus were assessed. Primary outcome was lung ultrasound score (LUS) of the dependent lung after 3-h lateral positioning. LUS of the left non-infected lung worsened while positioned in left-lateral position (from 1.33 ± 1.73 at baseline to 6.78 ± 4.49; p = 0.005). LUS of the right-infected lung improved when placed upward (9.22 ± 2.73 to 6.67 ± 3.24; p = 0.09), but worsened in right-lateral position (7.78 ± 2.86 to 13.33 ± 3.08; p < 0.001). PaO2/FiO2 improved in the left-lateral position (p = 0.005). In an animal model of right-lung pneumonia, left-lateral decubitus improved oxygenation, but collapsed the healthy lung. Right-lateral orientation further collapsed the diseased lung. Our data raise potential clinical concerns for the use of lateral position in mono-lateral pneumonia.

Lung Recruitment Guided by Ultrasonography in Unilateral Lung Injury

“…As pulmonary blood flow is almost entirely determined by the forces of gravity [12], the redistribution of blood flow to the healthy dependent lung result in a better V/Q. A potential complication of lateral positioning is the de-recruitment of the dependent lung due to lung and heart weight [13]. Other possible complication of lateral decubitus is the hyperinflation of injured lung, specifically atelectatic lung, in the nondependent position as consequence of gravitationally drived distribution of ventilation.…”

Asymmetrical Lung Injury: Management and Outcome

“…Moreover, an experimental model of unilateral pneumonia, recently showed a potential detrimental effect on the noninjured lung when placed in dependent position. 11 Ultrasound revealed increased atelectasis, probably from the increased superimposed pressure (generated by the heart, the contralateral lung, and ribs). Recent data during lateral position suggest that maintaining a sufficient positive-end-expiratory pressure (PEEP) level may be important.…”

“…Severe unilateral pneumonia or asymmetrical ARDS are challenging situations since MV faces a substantial imbalance in pulmonary mechanics, the less injured lung, highly compliant lung, and the stiffer sick lung. 11…”

“…Severe unilateral pneumonia or asymmetrical ARDS are challenging situations since MV faces a substantial imbalance in pulmonary mechanics, the less injured lung, highly compliant lung, and the stiffer sick lung. 11 There is no clear definition of an asymmetrical lung injury. The best described heterogeneity in pulmonary aeration in case of lung injury is the anteroposterior gradient due to gravity in ARDS.…”

Ten golden rules for individualized mechanical ventilation in acute respiratory distress syndrome

“…Chest physiotherapy should be initiated as soon as possible, even during controlled MV, to improve outcome and reduce complications. In particular, assisted mobilization, postural therapy, neuromuscular electrical stimulation, and respiratory muscle training may reduce the rate of muscle weakness among ICU patients, and manual or ventilator hyperinflation [103] , positioning [104] , active cycle of breathing, and subglottic secretion drainage may help in the reduction of respiratory complications such as atelectasis, ventilator-associated pneumonia, and tracheobronchitis [105] .…”