Perfusion index for assessing microvascular reactivity in septic shock after fluid resuscitation.
Rev Bras Ter Intensiva 2018;
30:135-143. [PMID:
29995077 PMCID:
PMC6031412 DOI:
10.5935/0103-507x.20180027]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Accepted: 12/25/2017] [Indexed: 01/08/2023] Open
Abstract
Objective
Microcirculation disturbances are implicated in the prognosis of septic
shock. Microvascular hyporesponsiveness can be assessed by an
oximetry-derived perfusion index and reactive hyperemia. Using this
perfusion index, we investigated reactive hyperemia and its relationship
with peripheral perfusion and clinical-hemodynamic parameters in septic
shock.
Methods
Eighty-two patients were evaluated: 47 with septic shock and 35 controls.
Tests were performed within 24 hours after admission. The perfusion index
was evaluated before and after a 3-min blood flow occlusion using a
time-response analysis for 5 min. The perfusion index was also evaluated in
the hyperemic phases and was mainly derived by mechanosensitive
(ΔPI0-60) and metabolic mechanisms
(ΔPI60-120). Correlation tests were performed between
reactive hyperemia and clinical-hemodynamic data.
Results
Reactive hyperemia measured by the perfusion index was significantly lower in
patients with septic shock, but this was only observed for the first 45
seconds after cuff-deflation. In the remaining period, there were no
statistical differences between the groups. The peaks in the perfusion index
were similar between groups, although the peak was reached more slowly in
the septic group. Values of ΔPI0-60 were lower in shock
[01% (-19% - -40%) versus 39% (6% - 75%); p = 0.001].
However, ΔPI60-120 was similar between the groups [43%
(18% - 93%) versus 48% (18% - 98%); p = 0.58]. The
time-to-peak of the perfusion index was correlated positively with the SOFA
scores and negatively with C-reactive protein; the peak of the perfusion
index was positively correlated with vasopressor doses; and the
ΔPI60-120 values were positively correlated with
C-reactive protein and vasopressor doses. No other significant correlations
occurred.
Conclusions
This perfusion index-based study suggests that septic shock promotes initial
peripheral vascular hyporesponsiveness and preserves posterior vascular
reactivity to a considerable degree. These results demonstrate a
time-dependent peripheral hyperemic response and a significant ischemic
reserve in septic shock.
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