An increase in urinary nitrite/nitrate excretion is associated with the hyperdynamic state after cardiovascular surgery.
OBJECTIVE
To test the hypotheses (1) that nitric oxide (NO) production is stimulated after cardiovascular surgery and is related to the hyperdynamic state and (2) that NO production is more prominent in patients with cardiopulmonary bypass.


METHODS
Prospective, clinical study.


METHODS
Intensive care unit in a university hospital.


METHODS
One hundred patients after cardiovascular surgery: coronary artery bypass graft with (n=53) and without (n=17) cardiopulmonary bypass, valve surgery with cardiopulmonary bypass (n=23) and thoracic aortic replacement with cardiopulmonary bypass (n=7).


METHODS
None.


RESULTS
Urinary nitrite/nitrate (NOx) excretion was measured by the high-performance liquid chromatography-Griess system as an index of endogenous NO production during the first 2 postoperative days. Hemodynamic variables, hematologic variables and serum C-reactive protein concentrations were measured after the operation. Urinary NOx concentrations were 146+/-70 and 190+/-93 micro mol/l, and the amounts of NOx excreted in the urine were 23+/-10 and 18+/-8 micro mol/h on the 1st and 2nd days, respectively. Urinary NOx excretions were positively correlated with the cardiac index (P<0.01), but inversely correlated with the systemic vascular resistance index (P<0.01). Urinary NOx concentrations were positively correlated with serum C-reactive protein concentrations (P<0.01), but inversely correlated with the cardiopulmonary bypass time (P<0.01). The urinary NOx concentration was highest in patients undergoing coronary artery bypass graft without cardiopulmonary bypass.


CONCLUSIONS
These findings suggest, firstly, that NO production is stimulated by a surgical inflammatory response and, secondly, that the endogenous NO contributes to the increase in cardiac output that accompanies the reduced systemic vascular resistance after cardiovascular surgery.
Department of Critical Care Medicine, Tokyo Medical and Dental University Graduate School, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8519, Japan. c.mitaka.icu@med.tmd.ac.jp
Chieko
C
Mitaka
Kuninori
K
Yokoyama
Takashi
T
Morimoto
Toshihisa
T
Nosaka
Makoto
M
Sunamori
Takasuke
T
Imai
D000368:Aged; D000369:Aged, 80 and over; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D002317:Cardiovascular Agents / Q000627:therapeutic use; D002318:Cardiovascular Diseases / Q000188:drug therapy / Q000601:surgery*; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D007564:Japan; D008297:Male; D008875:Middle Aged; D009566:Nitrates / Q000652:urine*; D009569:Nitric Oxide / Q000652:urine; D009573:Nitrites / Q000652:urine*; D011446:Prospective Studies; D018746:Systemic Inflammatory Response Syndrome
D002317:Cardiovascular Agents; D009566:Nitrates; D009573:Nitrites; D009569:Nitric Oxide