Redistribution of blood flow and lung volume between lungs in lateral decubitus postures during unilateral atelectasis and PEEP.

The effect of left lung atelectasis on the regional distribution of blood flow (Q), ventilation (V(A)) and gas exchange on the right lung ventilated with 100% O2 was studied in anesthetized dogs in the lateral decubitus posture. Q and V(A) were measured in 1.7 ml lung volume pieces using injected and aerosolized fluorescent microspheres, respectively. Hypoxic pulmonary vasoconstriction (HPV) in the atelectatic lung shifted flow to the ventilated lung. The increased flow in the ventilated lung ensured adequate gas exchange, compensating for the hypoxemia due to shunt contributed by the atelectatic lung. Left lung atelectasis caused a compensatory increase in the ventilated lung FRC that was smaller in the right (RLD) than left (LLD) lateral posture, the effect of lung compression by the atelectatic lung and mediastinal contents in the RLD posture. The O2 deficit measured by (A-a)DO2 increased with left lung atelectasis and was exacerbated in the LLD posture by 10 cm H2O PEEP, a result of increased shunt caused by a shift in Q from the ventilated to the atelectatic lung. The PEEP-induced O2 deficit was eliminated with inversion to the RLD posture.

[1]  R. Johnson,et al.  Effect of pneumonectomy on the remaining lung in dogs. , 1991, Journal of applied physiology.

[2]  R. Glenny,et al.  Extending fluorescent microsphere methods for regional organ blood flow to 13 simultaneous colors. , 2001, American journal of physiology. Heart and circulatory physiology.

[3]  E. d’Angelo,et al.  Comparative features of the transpulmonary pressure. , 1970, Respiration physiology.

[4]  L. A. Engel,et al.  Vertical distribution of perfusion and inspired gas in supine man. , 1981, Respiration physiology.

[5]  C. Dawson,et al.  Influence of inflation and atelectasis on the hypoxic pressor response in isolated dog lung lobes. , 1976, Cardiovascular research.

[6]  J. West,et al.  Distribution of blood flow and ventilation-perfusion ratio in the lung, measured with radioactive carbon dioxide. , 1960, Journal of applied physiology.

[7]  B. Marshall,et al.  Influence of Mixed Venous Oxygen Tension (PVO2) on Blood Flow to Atelectatic Lung , 1983, Anesthesiology.

[8]  A. Roos,et al.  Effect of negative-pressure inflation of the lung on pulmonary vascular resistance. , 1961, Journal of applied physiology.

[9]  D V Bates,et al.  Regional distribution of ventilation and perfusion as a function of body position. , 1966, Journal of applied physiology.

[10]  B. Marshall,et al.  Mechanical factors do not influence blood flow distribution in atelectasis. , 1985, Anesthesiology.

[11]  M. O’Neill,et al.  Time course of hypoxic pulmonary vasoconstriction: a rabbit model of regional hypoxia. , 1997, American journal of respiratory and critical care medicine.

[12]  A. Froese,et al.  Effects of anesthesia and paralysis on diaphragmatic mechanics in man. , 1974, Anesthesiology.

[13]  J. W. Shaw,et al.  Stimulus—response curves for the pulmonary vascular bed to hypoxia and hypercapnia , 1970, The Journal of physiology.

[14]  C. Mélot,et al.  PEEP inhibits hypoxic pulmonary vasoconstriction in dogs. , 1991, Journal of applied physiology.

[15]  S. Lai-Fook,et al.  A finite element analysis of the effects of the abdomen on regional lung expansion. , 1995, Respiration physiology.

[16]  R. Glenny,et al.  Spatial distribution of ventilation and perfusion in anesthetized dogs in lateral postures. , 2002, Journal of applied physiology.

[17]  LUNG FUNCTION STUDIES . II . THE RESPIRATORY DEAD SPACE 192 , 2004 .

[18]  A. C. Burton,et al.  Effect on pulmonary vascular resistance of inflation of the rabbit lungs. , 1958, Journal of applied physiology.

[19]  T. Amis,et al.  Effect of posture on inter-regional distribution of pulmonary ventilation in man. , 1984, Respiration physiology.

[20]  M. K. Sykes,et al.  CO2 and mechanical factors reduce blood flow in a collapsed lung lobe. , 1984, Journal of applied physiology: respiratory, environmental and exercise physiology.

[21]  B. Marshall,et al.  Hypoxic pulmonary vasoconstriction in dogs: effects of lung segment size and oxygen tension. , 1981, Journal of applied physiology: respiratory, environmental and exercise physiology.

[22]  K. Domino,et al.  Effect of positive end-expiratory pressure on hypoxic pulmonary vasoconstriction in the dog. , 1990, The American journal of physiology.

[23]  K. Rehder,et al.  Regional pulmonary perfusion and V/Q in awake and anesthetized-paralyzed man. , 1977, Journal of applied physiology: respiratory, environmental and exercise physiology.

[24]  B. Marshall,et al.  Continuity of response to hypoxic pulmonary vasoconstriction. , 1980, Journal of applied physiology: respiratory, environmental and exercise physiology.

[25]  J. Benumof.  Mechanism of decreased blood flow to atelectatic lung. , 1979, Texas reports on biology and medicine.

[26]  J. D. Young,et al.  Time course of the human pulmonary vascular response to 8 hours of isocapnic hypoxia. , 1997, The American journal of physiology.

[27]  F L Matthews,et al.  Stresses, strains, and surface pressures in the lung caused by its weight. , 1972, Journal of applied physiology.

[28]  E. d’Angelo,et al.  Topography of pleural surface pressure above resting volume in relaxed animals. , 1970, Journal of applied physiology.

[29]  J B West,et al.  Effect of lung volume on the distribution of pulmonary blood flow in man. , 1968, Respiration physiology.

[30]  Y. Henderson,et al.  THE RESPIRATORY DEAD SPACE , 1915 .

[31]  W. Guntheroth,et al.  Pulmonary blood flow and resistance during acute atelectasis in intact dogs. , 1970, Journal of applied physiology.

[32]  K. Beck,et al.  Pulmonary blood flow vs. gas volume at various perfusion pressures in rabbit lung. , 1985, Journal of applied physiology.

[33]  R. Hyatt,et al.  Effect of heart weight on distribution of lung surface pressures in vertical dogs. , 1986, Journal of applied physiology.

[34]  J. Benumof,et al.  Atelectatic lobe blood flow: open vs. closed chest, positive pressure vs. spontaneous ventilation. , 1981, Journal of applied physiology: respiratory, environmental and exercise physiology.

[35]  B. Marshall,et al.  The Effect of Pleural Pressure on the Hypoxic Pulmonary Vasoconstrictor Response in Closed Chest Dogs , 1988, Anesthesia and analgesia.

[36]  E. Ritman,et al.  Spatial distribution of pulmonary blood flow in dogs in left decubitus position. , 1974, The American journal of physiology.

[37]  C T DOLLERY,et al.  DISTRIBUTION OF BLOOD FLOW IN ISOLATED LUNG; RELATION TO VASCULAR AND ALVEOLAR PRESSURES. , 1964, Journal of applied physiology.

[38]  K. Rehder,et al.  Function of each lung during mechanical ventilation with ZEEP and with PEEP in man anesthetized with thiopental-meperidine. , 1973, Anesthesiology.

[39]  E H Wood,et al.  Effect of body position on vertical distribution of pulmonary blood flow. , 1970, Journal of applied physiology.

[40]  K. Rehder,et al.  Function of each lung in spontaneously breathing man anesthetized with thiopental-meperidine. , 1973, Anesthesiology.

[41]  K. Beck,et al.  Differences in regional vascular conductances in isolated dog lungs. , 1986, Journal of applied physiology.

[42]  L. Olson.  Effect of posture on static lung volumes and pulmonary mechanics in pneumonectomized rabbits. , 1993, Journal of applied physiology.

[43]  T. Amis,et al.  Effect of posture on inter-regional distribution of pulmonary perfusion and VA/Q ratios in man. , 1984, Respiration physiology.

[44]  C. Roussos,et al.  Diaphragmatic contraction and the gradient of alveolar expansion in the lateral posture. , 1977, Journal of applied physiology: respiratory, environmental and exercise physiology.