RESUMO
Microcirculation disturbances imply poor prognosis in septic shock. Microvascular reserve can be assessed by oximetry-derived Perfusion Index (PI) after vascular occlusion test (VOT). We investigated the relationship between PI during VOT, hyperlactatemia and mortality in septic shock and the role of adrenergic stimulus in these findings. The tests were performed in 106 patients within 24âh after admission. PI was evaluated before/after 03-min flow occlusion. Peaks of PI (ΔPI peak) and time-to-peak were evaluated. PI was also evaluated in hyperemic phases derived by mechanosensitive (ΔPI0-60) and metabolic mechanisms (ΔPI60-120). We compared nonsurvivors with survivors and patients with lowest and highest ΔPI peaks, divided by 50th percentile. ΔPI peak was evaluated in presence/absence of hyperlactatemia. A correlation test between ΔPI peaks and noradrenaline doses and an assessment after doses increasing were also performed. The ΔPI peak values were higher in nonsurvivors [79% (47%-169%) vs. 48% (25%-85%); P=0.003] although peaks were reached slower in nonsurvivors. ΔPI0-60 was similar between groups [-12% (-42% to 28%) vs. 01% (-16%-23%); Pâ=â0.211]. However, ΔPI60-120 was higher in nonsurvivors [49% (29%-84%) vs. 31% (12%-65%); Pâ=â0.035]. Additionally, the group with higher ΔPI peaks had higher mortality than those with lower peaks [HR 2.25 (95% CIâ=â1.32-4.14); Pâ=â0.003]. Mortality was extremely high in the presence of hyperlactatemia. ΔPI peaks were positively correlated with noradrenaline doses and increased after increasing doses.In conclusion, high values of PI during VOT indicate higher mortality in septic shock and are associated with adrenergic stimulus. Additionally, the assessment of PI-VOT appears to improve the predictive value of arterial lactate.
Assuntos
Perfusão , Ressuscitação/métodos , Choque Séptico/mortalidade , Choque Séptico/terapia , Idoso , Monitorização Transcutânea dos Gases Sanguíneos , Feminino , Humanos , Hiperlactatemia/metabolismo , Ácido Láctico/metabolismo , Masculino , Microcirculação , Pessoa de Meia-Idade , Oximetria , Índice de Perfusão , Valor Preditivo dos Testes , Prognóstico , Estudos Prospectivos , Fluxo Pulsátil , Fluxo Sanguíneo RegionalRESUMO
The intensity of lactate minimum (LM) has presented a good estimate of the intensity of maximal lactate steady-state (MLSS); however, this relationship has not yet been verified in the mouse model. We proposed validating the LM protocol for swimming mice by investigating the relationship among intensities of LM and MLSS as well as differences between sexes, in terms of aerobic capacity. Nineteen mice (male: 10, female: 9) were submitted to the evaluation protocols for LM and MLSS. The LM protocol consisted of hyperlactatemia induction (30 s exercise (13% body mass (bm)), 30 s resting pause and exhaustive exercise (13% bm), 9 min resting pause and incremental test). The LM underestimated MLSS (mice: 17.6%; male: 13.5%; female: 21.6%). Pearson's analysis showed a strong correlation among intensities of MLSS and LM (male (r = 0.67, p = 0.033); female (r = 0.86, p = 0.003)), but without agreement between protocols. The Bland-Altman analysis showed that bias was higher for females (1.5 (0.98) % bm; mean (MLSS and LM): 4.4%-6.4% bm) as compared with males (0.84 (1.24) % bm; mean (MLSS and LM): 4.5%-7.5% bm). The error associated with the estimated of intensity for males was lower when compared with the range of means for MLSS and LM. Therefore, the LM test could be used to determine individual aerobic intensity for males (considering the bias) but not females. Furthermore, the females supported higher intensities than the males. The differences in body mass between sexes could not explain the higher intensities supported by the females.