Ef. Mondejar et al., VENTILATION WITH POSITIVE END-EXPIRATORY PRESSURE REDUCES EXTRAVASCULAR LUNG WATER AND INCREASES LYMPHATIC FLOW IN HYDROSTATIC PULMONARY-EDEMA, Critical care medicine, 24(9), 1996, pp. 1562-1567
Objective: To analyze the effect of different levels of positive end-e
xpiratory pressure (PEEP) on extravascular lung water and on lymphatic
drainage through the thoracic duct during hydrostatic pulmonary edema
. Design: Randomized, controlled, experimental study, Setting: Researc
h laboratory of a tertiary care hospital, Subjects: Eighteen beagle do
gs weighing between 10 and 19 kg. Interventions: Dogs were anesthetize
d and cannulated via a thoracic duct, Hydrostatic pulmonary edema was
provoked by inflating the balloon of a Foley catheter in the left atri
um, Different amounts of PEEP were applied. Measurements and Main Resu
lts: Extravascular lung water was determined by the double indicator d
ilution method (indocyanine green in glucoside solution at 0 degrees C
), and lymphatic drainage was measured every 30 mins, After a baseline
measurement, the left atrial pressure was increased to 24 to 26 mm Hg
, and measurements were recorded after 30, 60, 90, and 120 mins. The a
nimals were divided into three groups, Group I (n = 6): PEEP of 20 cm
H2O was instituted at 120 mins, and the other determinations were made
without PEEP; group II (n = 7): PEEP of 10 cm H2O was instituted at 6
0 and 90 mins; group III (n = 5): PEEP of 20 cm H2O was instituted at
60 and 90 mins, Extravascular lung water in creased after the increase
of left atrial pressure in all three groups, After 90 mins, the extra
vascular lung water was significantly greater (p<.01) in group I (no P
EEP application) at 21.2 +/- 5.1 mL/kg than in groups II and III (with
10 and 20 cm H2O of PEEP) at 12.8 +/- 2.01 and 14.8 +/- 4.8 mL/kg, re
spectively. Lymphatic drainage tended to increase over time in all thr
ee groups, Ninety minutes after the left atrial pressure increase, lym
phatic drainage was significantly greater (p <.05) in group II, at 6.0
6 +/- 2.53 mL/kg/30 mins, than in group I, at 2.83 +/- 0.76 mL/kg/30 m
ins, Conclusions: a) The application of PEEP levels of between 10 and
20 cm H2O limits the increase of extravascular lung water in cases of
hydrostatic pulmonary edema; and b) the application of 10 cm H2O of PE
EP increases the lymphatic flow through the thoracic duct.