Inhaled nitric oxide improves hemodynamics during a venous air infusion (VAI) in dogs.
OBJECTIVE
To evaluate the hemodynamic effects of inhaled nitric oxide (NO) during a venous air infusion (VAI) in dogs. We also addressed the question of whether NO therapy changes thromboxane (Tx) A(2) release and nitrate/nitrite production during a VAI.


METHODS
Prospective trial.


METHODS
University laboratory.


METHODS
Anesthetized mongrel dogs received a VAI (0.2 ml x kg(-1)x min(-1)) after the measurement of baseline hemodynamics. Control dogs (n = 8) received no further treatment. After 30 min of VAI, NO 3 ppm inhalation was initiated (n = 7) for 30 min, followed by 30 min without NO inhalation, and then a final 30 min of NO 40 ppm treatment. Hemodynamic variables were registered and arterial and mixed venous blood samples were drawn for gas analysis and for the determinations of serum TxB(2) (by enzyme-linked immunosorbent assay) and nitrate/nitrite (by high-performance liquid chromatography) levels.


RESULTS
The cardiac index increased 24 % and the pulmonary vascular resistance index decreased 30 % during both periods of NO inhalation. Arterial oxygen tension and arterial oxygen saturation were slightly lower after NO therapy. Nitrate/nitrite concentrations were unaltered in the control group and there were no differences between the arterial and mixed venous serum nitrate/nitrite levels. Nitrite concentrations remained below 1 microM in both groups of animals, but the nitrate concentration increased after inhalation of 40 ppm NO. Serum TxB(2) increased after 60 min of VAI in the control group, but there was no increase in NO-treated animals (all p < 0.05)


CONCLUSIONS
Nitrate/nitrite concentrations were unaltered after VAI in dogs. NO therapy attenuated TxA(2) release and improved hemodynamics, but not blood oxygenation, in dogs with a VAI. There were no differences between the responses to 3 ppm and 40 ppm NO.
Tanus-Santos
J E
JE
Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas, P. O. Box 6111, 13081-970 Campinas, São Paulo, Brazil. tanus@turing.unicamp.br
Moreno
H
H
Moreno
R A
RA
Martins
M L
ML
Pereira
R
R
de Nucci
G
G
D000280:Administration, Inhalation; D000818:Animals; D004195:Disease Models, Animal; D004285:Dogs; D004353:Drug Evaluation, Preclinical; D004618:Embolism, Air / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006976:Hypertension, Pulmonary / Q000097:blood / Q000188:drug therapy / Q000503:physiopathology; D008297:Male; D009566:Nitrates / Q000097:blood; D009569:Nitric Oxide / Q000008:administration & dosage* / Q000494:pharmacology; D009573:Nitrites / Q000097:blood; D011446:Prospective Studies; D013928:Thromboxane A2 / Q000097:blood; D013929:Thromboxane B2 / Q000097:blood; D014665:Vasodilator Agents / Q000008:administration & dosage* / Q000494:pharmacology; D014680:Veins
D009566:Nitrates; D009573:Nitrites; D014665:Vasodilator Agents; D009569:Nitric Oxide; D013929:Thromboxane B2; D013928:Thromboxane A2