Nitric oxide (NO) metabolite levels are not increased during hypotensive periods in human sepsis

Purpose

Excess NO production has been proposed to cause the hemodynamic derangements of septic shock. This study was undertaken to determine whether serum NO metabolite levels correlate with hemodynamic changes in human sepsis.

Methods

A 12-month prospective study of surgical ICU patients with SIRS, sepsis, severe sepsis or septic shock was undertaken. Serum NO₂/NO₃ levels were determined by chemiluminescence from blood drawn during blood culture acquisition or hypotension (SBP <90 mmHg), then daily for 7 days or until ICU discharge or death. The following were collected: vital signs, pulmonary artery catheter data, white blood cell count (WBC) and arterial base deficit (BD). T-test analysis compared NO₂/NO₃ levels in hypotensive and normotensive patients. Pearson correlation coefficients were determined for NO₂/NO₃ and the variables above. Data are mean ± SEM; P < 0.05 defined significance.

Results

NO₂/NO₃ levels were 12.2 ± 3.8 pmol/μl in 13 hypotensive vs 12.7 ± 2.0 in 9 normotensive patients (NS). Correlation coefficients (r²) are depicted:

Conclusions

NO metabolite levels are not different in hypotensive and normotensive septic patients. There is poor correlation between NO metabolite levels and physiologic changes in human sepsis. Further study regarding the role of NO as the principal vasodilator in sepsis is warranted.

Table 1 Table (abstract P029)