Scambi di liquido e proteine nella pleura : distribuzione intrapleurica di un bolo ed effetto dell’alterazione delle forze di Starling su volume e composizione del liquido pleurico.

Exchanges of liquid and proteins in pleural space: intrapleural distribution of a liquid bolus and effect of Starling forces alteration on volume and composition of pleural liquid. Distribution and mixing time of boluses with labeled albumin in pleural space of rabbits were determined by sampling pleural liquid at different times in various intercostal spaces (ics), and in mediastinum. During sampling, lung and chest wall were kept apposed by lung inflation. This was not necessary in costo-phrenic sinus. Here, 10 min after injection, lung inflation increased concentration of labeled albumin by 50%. Lung inflation probably displaces some pleural liquid cranio-caudally. Boluses of 0.1-1 ml did not preferentially reach mediastinal regions. Time for an approximate mixing was ~1 h for 0.1 ml, and ~30 min for 1 ml. This mixing time does not substantially affect determination of contribution of lymphatic drainage through stomata to overall removal of labeled albumin from 0.3 ml hydrothoraxes lasting 3 h. The effect of approximately 25% or 35% blood loss (b.l.) on volume, pressure, and protein concentration of pleural liquid has been determined in rabbits. Volume and pressure of pleural liquid did not change with 25% b.l. 30 and 60 min after hemorrhage, and with 35% b.l. at 30. With 35% b.l. protein concentration of pleural liquid was 85% greater than control. Decrease in arterial plasma protein concentration, hematocrit, and pH after hemorrhage fit literature data. Ventilation at 15 and 30 min increased by 16% and 23%, with 25% b.l., but it did not change with 35% b.l., a condition borderline to survival. Pleural liquid seems protected against derangements from hemorrhage up to 25% b.l. for periods shorter than 1 h.