[Significance of peripheral perfusion index in early diagnosis and goal-directed therapy of septic shock patients: a prospective single-blind randomized controlled trial].

OBJECTIVE: To investigate the application of peripheral perfusion index (PPI) in early diagnosis and goal-directed therapy of septic shock, and to provide reference for the early clinical diagnosis and treatment of septic shock.

METHODS: A prospective single-blind randomized controlled trial (RCT) was conducted. Adult patients with sepsis admitted to emergency medical department and intensive care unit (ICU) of the First People's Hospital of Lianyungang City in Jiangsu Province from January 2013 to December 2016 were enrolled. The patients were randomly divided into two groups (n = 46). The PPI group was defined using PPI < 1.4 as diagnosis of septic shock standard, and PPI > 2 as treatment guide target. Control group was defined according to the traditional diagnostic criteria of shock which systolic blood pressure was less than 90 mmHg (1 mmHg = 0.133 kPa) or systolic blood pressure value decrease > 40 mmHg baseline and bundle treatment was performed. The volume of fluid resuscitation, organ dysfunction, the sequential organ failure score (SOFA), acute physiology and chronic health evaluation II (APACHE II) score, continuous renal replacement therapy (CRRT) time, mechanical ventilation (MV) time, the length of ICU stay and 28-day mortality were observed.

RESULTS: There were 39 and 27 septic shock patients in PPI group and control group respectively. The diagnostic criteria of traditional septic shock with blood pressure as "gold standard", the sensitivity of PPI < 1.4 for septic shock was 94.3%, the specificity was 28.2%, the authenticity was 66.3%, the positive predictive value was 64.1%, the negative predictive value was 78.6%, the positive likelihood ratio was 1.31, the negative likelihood ratio was 0.18. The per capita fluid replacement within 24 hours in the PPI group was significantly higher than that in the control group (mL: 4 601±1 250 vs. 3 458±1 006, P < 0.01), but there was no significant difference in the per capita volume of the patients diagnosed as septic shock (mL: 4 596±1 320 vs. 4 205±1 058, P > 0.05). Compared with the control group, the PPI group treated patients within 48 hours with less vascular active drugs (cases: 6 vs. 15), APACHE II and SOFA score were lower (48 hours: APACHE II was 10.2±2.1 vs. 12.0±3.2; 72 hours: SOFA was 5.1±1.8 vs. 6.0±2.1, APACHE II was 8.9±1.8 vs. 9.8±2.2), the period of CRRT and the length of ICU stay were shorter [the period of CRRT (days): 3.0±0.9 vs. 3.6±1.4, the length of ICU stay (days): 5.2±2.1 vs. 6.3±2.9), the difference was statistically significant (all P < 0.05). There was no significant difference in the liver and kidney function index, arterial blood lactic acid (Lac), MV time (days: 3.3±1.4 vs. 3.5±1.2) and 28-day mortality (15.22% vs. 19.57%) between two groups (all P > 0.05).

CONCLUSIONS: The inadequacy of microcirculatory perfusion by oximetry-derived PPI is more sensitive to the diagnosis of septic shock than hypotension of systemic circulation. With PPI guiding the fluid resuscitation of septic shock patients, vasopressors can be withdrawn earlier and the duration of the CRRT and ICU can be decreased.