Lymph and pulmonary response to isobaric reduction in plasma oncotic pressure in baboons.
Plasma colloid osmotic pressure was reduced by 76% (from 19.6 +/- 0.6 to 4.7 +/- 1.5 mm Hg) in five baboons while pulmonary capillary hydrostatic pressure was maintained at a normal level. This resulted in fluid retention, weight gain, peripheral edema and ascites, but no pulmonary edema. Thoracic duct lymph flow increased 6-fold and pulmonary lymph flow 7-fold. Thoracic duct lymph had a lower colloid osmotic pressure (2.0 +/- 0.7 mm Hg) than plasma (4.7 +/- 1.5 mm Hg), whereas the colloid osmotic pressure of pulmonary lymph (4.7 +/- 0.7 mm Hg) was the same as that of plasma. The lymph-plasma ratio for albumin fell in thoracic duct lymph but remained unchanged in pulmonary lymph. The difference between plasma colloid osmotic pressure and pulmonary artery wedge pressure decreased from 15.3 +/- 1.9 to -0.7 +/- 2.9 mm Hg. Despite this increase in filtration force, the lungs were protected from edema formation by a decrease of 11 mm Hg in pulmonary interstitial colloid osmotic pressure and a 7-fold increase in lymph flow.
D000818:Animals; D001201:Ascites / Q000209:etiology; D001769:Blood; D001794:Blood Pressure; D001835:Body Weight; D004487:Edema / Q000209:etiology; D000882:Haplorhini; D008196:Lymph; D008208:Lymphatic System / Q000502:physiology*; D008297:Male; D008833:Microcirculation; D009997:Osmotic Pressure; D010215:Papio; D011652:Pulmonary Circulation; D013897:Thoracic Duct / Q000502:physiology