Effects of single-lung inflation on inspiratory muscle function in dogs

• Published in: The Journal of physiology Vol. 576; no. 1; pp. 269 - 277
• Main Authors: De Troyer, André, Leduc, Dimitri
• Format: Journal Article
• Language: English
• Published: Oxford, UK The Physiological Society 01.10.2006; Blackwell Publishing Ltd; Blackwell Science Inc
• Subjects: Animals; Dogs; Electromyography; Inhalation - physiology; Lung - pathology; Lung - physiopathology; Lung Transplantation - pathology; Lung Transplantation - physiology; Lung Volume Measurements; Muscle Contraction - physiology; Pulmonary Emphysema - surgery; Respiratory; Respiratory Mechanics - physiology; Respiratory Muscles - physiopathology
• ISSN: 0022-3751; 1469-7793
• DOI: 10.1113/jphysiol.2006.112797

After single-lung transplantation (SLT) for emphysema, a hyperinflated (native) lung operates in parallel with a normal (transplanted) lung. The interpulmonary distribution of the changes in pleural pressure (Δ P pl ) during breathing, however, is unknown. To approach the problem, two endotracheal tubes were inserted in the right and left main stem bronchi of anaesthetized dogs, one lung was passively inflated, and the values of inspiratory Δ P pl over the two lungs were assessed by measuring the changes in airway opening pressure (Δ P ao ) in the two tubes during occluded breaths. With single-lung inflation, Δ P ao decreased in both lungs, but the decrease in the inflated lung was invariably larger than in the non-inflated lung; when transrespiratory pressure in the inflated lung was set at 30 cmH 2 O, Δ P ao in this lung was 27.7 ± 2.0% of the value of functional residual capacity (FRC), whereas Δ P ao in the non-inflated lung was 74.4 ± 4.5% ( P < 0.001). This difference was abolished after the ventral mediastinal pleura was severed. The ribs in both hemithoraces were displaced cranially with inflation, such that the displacement in the contralateral hemithorax was 75% of that in the ipsilateral hemithorax, and parasternal intercostal activity remained unchanged. These observations suggest that in patients with SLT for emphysema (1) the inspiratory Δ P pl over the transplanted lung are greater than those over the native lung and (2) this difference results primarily from the greater pressure-generating ability of the inspiratory muscles, in particular the diaphragm, on the transplanted side.