Vasopressin and renin-angiotensin both maintain arterial pressure
during peep in non-expanded, conscious dogs.
Kaczmarczyk, Gabriele, Susanne Vogel, Martin Krebs, Harald
B[umlaut]unger, and Anna Scholz.
AG Experimentelle An[umlaut]asthesie, Klinik f[umlaut]ur
An[umlaut]asthesiologie und operative Intensivmedizin, Virchow
-Klinikum der Humboldt-Universit[umlaut]at zu Berlin Augustenburger
Platz, 13353 Berlin, Germany
APStracts 3:0264R, 1996.
Increases of plasma arginine vasopressin (AVP) and plasma renin
activity (PRA) during controlled mechanical ventilation (CMV) with
positive end-expiratory pressure (PEEP) induce positive fluid
balances by decreasing renal excretion. We investigated whether
elevated levels of AVP and/or PRA maintain mean arterial pressure
(MAP) during PEEP under conditions where plasma volume is not
expanded. 6 conscious chronically tracheotomized beagle dogs, kept
under standardized conditions were investigated in four protocols. 1.
control: 1 h spontaneous breathing with a continuous positive airway
pressure of 4 cm H2O (CPAP 4) followed by 2 h CMV with PEEP resulting
in a mean airway pressure of about 20 cm H2O (CMV 20 referred to
as,PEEP"); 2. Vasopressin blockade: 1 h CPAP 4, 2 h PEEP after
the iv application of an AVP V1-receptor antagonist (AVPA); 3.
Converting enzyme inhibition: 1 h CPAP 4, 2 h PEEP plus angiotensin
converting enzyme inhibition (ACEI); 4. Combined blockade: 1 h CPAP
4, 2 h PEEP plus AVPA+ACEI. -In AVPA+ACEI, MAP decreased during PEEP
from 101+/-4 to 75+/-10 mm Hg, glomerular filtration rate (GFR)
decreased from 3.6+/-0.3 to 1.7+/-0.7 ml x min-1 x kg-1 body wt,
heart rate increased from 95+/-10 to 122+/-7 b/min, plasma
aldosterone increased from 62+/-26 to 353+/-63 pg/ml, plasma
epinephrine increased from 81+/-15 to 352+/-89 pg/ml (all changes
p<0.05), and plasma norepinephrine did not change. Neither MAP
and GFR changed during PEEP in control experiments in which both PRA
and AVP increased, in AVPA experiments in which PRA increased or in
ACEI experiments in which AVP increased. We conclude that both AVP
and Angiotensin II contribute to the maintenance of MAP and GFR
during PEEP. When both hormones are inhibited no immediate
compensation exists to prevent an acute fall in MAP and GFR.
Received 26 June 1995; accepted in final form 28 March 1996.
APS Manuscript Number R397-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 25 July 1996