Introduction:

it has been shown that mechanical ventilation induces production of proinflammatory cytokines. The Neutrophil-to-lymphocyte ratio (N/L r) is a simple parameter that is used to assess the inflammatory state.

Objective:

to compare the means and percentages of elevated neutrophil/lymphocyte ratio (N/L r) in patients under general anesthesia with volume-controlled mechanical ventilation (VCMV) and pressure-controlled mechanical ventilation (PCMV).

Material and methods:

adults ≥ 18 years old, ASA I-III, with elective surgery and general anesthesia. Randomized clinical trial: 25 patients with VCMV and 25 with PCMV. All patients had two blood counts determined: before and 2 hours after surgery. N/L r was measured as a ratio and dichotomous (< 3 or ≥ 3). Statistical analysis: the t-Student, χ2 and McNemar tests were used.

Results:

50 patients (27 women and 23 men) with a mean age of 47 ± 16 years (range 18-84 years) were studied. The VCMV group tended to present lower values of means and percentages N/L r, however, it was not statistically significant (p = 0.06). In the paired comparison, both groups presented a statistically significant increase in the means and percentages of N/L r. However, the percentage of N/L r > 3 in the PCMV group was 64%, while in the VCMV group it was 40%.

Conclusions:

the VCMV presents lower means and percentages of N/L r compared to PCMV, however, they were not statistically significant.

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