Ventilation and Perfusion Distribution during Altered PEEP in the Left Lung in the Left Lateral Decubitus Posture with Unchanged Tidal Volume in Dogs

Hung Chang；Stephen J. Lai-Fook；Karen B. Domino；Jack Hildebrandt；H. Thomas Robertson；Robb W. Glenny；Jane-Yi Hsu；Shih-Chun Lee；Michael P. Hlastala

gas exchange ； lung mechanics ； fluorescent microspheres ； regional pulmonary blood flow distribution

The Chinese Journal of Physiology

49卷2期（2006 / 04 / 01）

74 - 82

英文

Previous studies in anesthetized humans positioned in the left lateral decubitus (LLD) posture have shown that unilateral positive end-expiratory pressure (PEEP) to the dependent lung produce a more even ventilation distribution and improves gas exchange. Unilateral PEEP to the dependent lung may offer special advantages during LLD surgery by reducing the alveolar-to-arterial oxygen pressure difference {(A-a)PO2 or venous admixture} in patients with thoracic trauma or unilateral lung injury. We measured the effects of unilateral PEEP on regional distribution of blood flow (Q) and ventilation (V(subscript A)) using fluorescent microspheres in pentobarbital anesthetized and air ventilation dogs in left lateral decubitus posture with synchronous lung inflation. Tidal volume to left and right lung is maintained constant to permit the effect on gas exchange to be examined. The addition of unilateral PEEP to the left lung increased its FRC with no change in left-right blood flow distribution or venous admixture. The overall lung V(subscript A)/Q distribution remained relatively constant with increasing unilateral PEEP. Bilateral PEEP disproportionately increased FRC in the right lung but again produced no significant changes in venous admixture or V(subscript A)/Q distribution. We conclude that the reduced dependent lung blood flow observed without PEEP occurs secondary to a reduction in lung volume. When tidal volume is maintained, unilateral PEEP increases dependent lung volume with little effect of perfusion distribution maintaining gas exchange.

1. Agostoni, E.,D`Angelo, E.(1970).Comparative features of the transpulmonary pressure.Respir. Physiol,11,76-83.
2. Altemeier, W.A.,Robertson, H.T.,Glenny, R.W.(1998).Pulmonary gas-exchange analysis by using simultaneous deposition of aerosolized and injected microspheres.J. Appl. Physiol,85,2344-2351.
3. Baehrendtz, S.,Klingstedt, C.(1984).Differential ventilation and selective PEEP during anaesthesia in the lateral decubitus posture.Acta. Anaesthesiol. Scand,28,252-259.
4. Baehrendtz, S.,Santesson, J.,Bindslev, L.,Hedenstierna, G.,Matell, G.(1983).Differential ventilation in acute bilateral lung disease. Influence on gas exchange and central haemodynamics.Acta. Anaesthesiol. Scand,27,270-277.
5. Blanch, L.,Aguilar, J.,Villagra, A.(2003).Unilateral lung injury.Curr. Opin. Crit. Care,9,33-38.
6. Chang, H.,Lai-Fook, S.,Domino, K.,Schimmel, C.,Hildebrandt, J.,Robertson, H.,Glenny, R.,Hlastala, M.(2002).Spatial distribution of ventilation and perfusion in anesthetized dogs in lateral postures.J. Appl. Physiol,92,745-762.
7. Dyhr, T.,Nygard, E.,Laursen, N.,Larsson, A.(2004).Both lung recruitment maneuver and PEEP are needed to increase oxygenation and lung volume after cardiac surgery.Acta. Anaesthesiol. Scand.,48,187-197.
8. Fowler, W.S.(1948).Lung function studies II. The respiratory dead space.Am. J. Physiol.,154,405-416.
9. Greenleaf, J.F.,Ritman, E.L.,Sass, D.J.,Wood, E.H.(1974).Spatial distribution of pulmonary blood flow in dogs in left decubitus position.Am. J. Physiol,227,230-244.
10. Hakim, T.,Lisbona, R.,Dean, G.(1987).Graviity-independent inequality in pulmonary blood flow in humans..J. Appl. Physiol,63,1114-1121.
11. Hedenstierna, G.,Baehrendtz, S.,Klingstedt, C.,Santesson, J.,Soderborg, B.,Dahlborn, M.,Bindslev, L.(1984).Ventilation and perfusion of each lung during differential ventilation with selective PEEP.Anesthesiology,61,369-376.
12. Hlastala, M.P.,Berger, A.J.(2001).Physiology of Respiration: Oxford University Press.Inc.
13. Hoffman, E. A.,Ritman, E.L.(1985).Effect of body orientation on regional lung expansion in dog and sloth.J. Appl. Physiol,59,481-191.
14. Kallas, H.,Domino, K.B,Glenny, R.W.,Anderson, E.,Hlastala, P. M.(1998).Pulmonary blood flow distribution changes with low levels of positive end-expiratory pressure.Anesthesiology,88,1291-1299.
15. Klingstedt, C.,Baehrendtz, S.,Bindslev, L.,Hedenstierna, G.(1985).Lung and chest wall mechanics during differential ventilation with selective PEEP.Acta. Anaesthesiol. Scand.,29,716-721.
16. Klingstedt, C.,Hedenstierna, G.,Baehrendtz, S.,Lundqvist, H.,Strandberg, A.,Tokics, L.,Brismar, B.(1990).Ventilationperfusion relationships and atelectasis formation in the supine and lateral positions during conventional mechanical and differential ventilation.Acta. Anaesthesiol. Scand,34,421-429.
17. Krayer, S.,Rehder, K.,Vettermann, J.,Didier, E.,Ritman, E.(1989).Position and motion of the human diaphragm during anesthesia-paralysis.Anesthesiology,70,891-898.
18. Mure, M.,Domino, K.B.,Robertson, T.,Hlastala, M.P.,Glenny, R. W.(1998).Pulmonary blood flow does not redistribute in dogs with reposition from supine to left lateral position.Anesthesiology,89,483-492.
19. Olson, L.E.,Hoffman, E.A.(1995).Heart-lung interactions determined by electron beam X-ray CT in laterally recumbent rabbits.J. Appl. Physiol.,78,417-427.
20. Reed, J.H.,Wood, E.H.(1970).Effect of body position on vertical distribution of pulmonary blood flow.J. Appl. Physiol,28,303-311.
21. Rehder, K.,Sessler, A.D.(1973).Function of each lung in spontaneously breathing man anesthetized with thiopentalmeperidine.Anesthesiology,38,320-327.
22. Rehder, K.,Wenthe, F.M.,Sessler, A.D.(1973).Function of each lung during mechanical ventilation with ZEEP and with PEEP in man anesthetized with thiopental-meperidine..Anesthesiology,39,597-606.
23. Roussos, C.S.,Martin, R.R.,Engel, L.A.(1977).Diaphragmatic contraction and the gradient of alveolar expansion in the lateral posture.J. Appl. Physiol.,43,32-38.
24. Schimmel, C.,Grazer, D.,Glenny, R.(2001).Extending fluorescent microsphere methods for regional organ blood flow to 13 simultaneous colors.Am. J. Physiol.: Heart. Circ. Physiol,280,2496-2506.
25. Wendt, M.,Hachenbert, T.,Winde, G.,Lawin, P.(1989).Differential ventilation with low-flow CPAP and CPPV in the treatment of unilateral chest trauma.Intens. Care Med.,15,209-211.