Association between mean arterial pressure and sublingual microcirculation during major non-cardiac surgery: Post hoc analysis of a prospective cohort.

OBJECTIVE: To test the hypothesis that there is an association between mean arterial pressure (MAP) and sublingual perfusion during major surgery, and perhaps an identifiable harm threshold. METHODS: This post hoc analysis of a prospective cohort included patients who had elective major non-cardiac surgery with a duration of ≥2 h under general anesthesia. We assessed sublingual microcirculation every 30 min using SDF+ imaging and determined the De Backer score, Consensus Proportion of Perfused Vessels (Consensus PPV), and the Consensus PPV (small). Our primary outcome was the relationship between MAP and sublingual perfusion which was evaluated with linear mixed effects modeling. RESULTS: A total of 100 patients were included, with MAP ranging between 65 mmHg and 120 mmHg during anesthesia and surgery. Over a range of intraoperative MAPs between 65 and 120 mmHg, there were no meaningful associations between blood pressure and various measures of sublingual perfusion. There were also no meaningful changes in microcirculatory flow over 4.5 h of surgery. CONCLUSIONS: In patients having elective major non-cardiac surgery with general anesthesia, sublingual microcirculation is well maintained when MAP ranges between 65 and 120 mmHg. It remains possible that sublingual perfusion will be a useful marker of tissue perfusion when MAP is lower than 65 mmHg.

The use of mean circulatory filling pressure analogue for monitoring hemodynamic coherence: A post-hoc analysis of the SPARSE data and proof-of-concept study.

BACKGROUND: Dissociation between macrocirculation and microcirculation is often observed in surgical patients. OBJECTIVE: To test the hypothesis that the analogue of mean circulatory filling pressure (Pmca) can monitor hemodynamic coherence during major non-cardiac surgery. METHODS: In this post-hoc analysis and proof-of-concept study, we used the central venous pressure (CVP), mean arterial pressure (MAP), and cardiac output (CO) to calculate Pmca. Efficiency of the heart (Eh), arterial resistance (Rart), effective arterial elastance (Ea), venous compartment resistance (Rven), oxygen delivery (DO2), and oxygen extraction ratio (O2ER) were also calculated. Sublingual microcirculation was assessed using SDF + imaging, and the De Backer score, Consensus Proportion of Perfused Vessels (Consensus PPV), and Consensus PPV (small) were determined. RESULTS: Thirteen patients were included, with a median age of 66 years. Median Pmca was 16 (14.9-18) mmHg and was positively associated with CO [p < 0.001; a 1 mmHg increase in Pmca increases CO by 0.73 L  min-1 (p < 0.001)], Eh (p < 0.001), Rart (p = 0.01), Ea (p = 0.03), Rven (p = 0.005), DO2 (p = 0.03), and O2ER (p = 0.02). A significant correlation was observed between Pmca and Consensus PPV (p = 0.02), but not with De Backer Score (p = 0.34) or Consensus PPV (small) (p = 0.1). CONCLUSION: Significant associations exist between Pmca and several hemodynamic and metabolic variables including Consensus PPV. Adequately powered studies should determine whether Pmca can provide real-time information on hemodynamic coherence.

Microcirculation-guided treatment improves tissue perfusion and hemodynamic coherence in surgical patients with septic shock.

PURPOSE: Severe sepsis and septic shock may impair microcirculatory perfusion and cause organ dysfunction. The aim of this pilot study was to assess a new microcirculation-guided resuscitation strategy in patients with septic shock undergoing emergency abdominal surgery. METHODS: A microcirculation-guided treatment algorithm was developed and applied intraoperatively following restoration of systemic hemodynamics. Sublingual microcirculation was monitored with Sidestream DarkField (SDF +) imaging technique. The primary objective was to investigate the change in De Backer score, Consensus Proportion of Perfused Vessels (Consensus PPV), and Consensus PPV (small) and its association with venous-to-arterial carbon dioxide difference (v-aPCO2). RESULTS: Thirteen consecutive patients were included in the study. Microcirculation-guided resuscitation resulted in an increase of 0.49 mm-1 in the De Backer score (p < 0.001), an increase of 2.28% in the Consensus PPV (p < 0.001), and an increase of 2.26% in the Consensus PPV (small) (p < 0.001) for every 30 min of additional intraoperative time. All microcirculation variables were negatively correlated with v-aPCO2 (rho = - 0.656, adj-p < 0.001; rho = - 0.623; adj-p < 0.001; rho = - 0.597, adj-p < 0.001, respectively) at each intraoperative time point. Lactate levels were negatively correlated with Consensus PPV (rho = - 0.464; adj-p = 0.002) and Consensus PPV (small) (rho = - 0.391, adj-p < 0.001). Survival at 30 days, 90 days, and 1 year were 76.9%, 76.9%, and 61.5%, respectively. CONCLUSIONS: The intraoperative use of microcirculation-guided resuscitation strategy may improve tissue perfusion and hemodynamic coherence in patients with septic shock.