Elevated preoperative suPAR is a strong and independent risk marker for postoperative complications in patients undergoing major noncardiac surgery (SPARSE)

The Relation of Calculated Plasma Volume Status to Sublingual Microcirculatory Blood Flow and Organ Injury

BACKGROUND

The calculated plasma volume status (cPVS) was validated as a surrogate of intravascular filling. The aim of this study is to assess the cPVS in relation to sublingual perfusion and organ injury.

METHODS

Pre- and postoperative cPVS were obtained by determining the actual and ideal plasma volume levels in surgical patients. The sublingual microcirculation was assessed using SDF imaging, and we determined the De Backer score, the Consensus Proportion of Perfused Vessels (Consensus PPV), and the Consensus PPV (small). Our primary outcome was the assessment of the distribution of cPVS and its association with intraoperative sublingual microcirculation and postoperative complications.

RESULTS

The median pre- and postoperative cPVS were -7.25% (IQR -14.29--1.88) and -0.4% (IQR -5.43-6.06), respectively (p < 0.001). The mean intraoperative administered fluid volume was 2.5 ± 2.5 L (1.14 L h^-1). No statistically significant correlation was observed between the pre- or postoperative cPVS and sublingual microcirculation variables. Higher preoperative (OR = 1.04, p = 0.098) and postoperative cPVS (OR = 1.057, p = 0.029) were associated with postoperative organ injury and complications (sepsis (30%), anemia (24%), respiratory failure (13%), acute kidney injury (6%), hypotension (6%), stroke (3%)).

CONCLUSIONS

The calculated PVS was associated with an increased risk of organ injury and complications in this cohort.

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.

Biomarkers as Prognostic Predictors and Therapeutic Guide in Critically Ill Patients: Clinical Evidence

A biomarker is a molecule that can be measured in a biological sample in an objective, systematic, and precise way, whose levels indicate whether a process is normal or pathological. Knowing the most important biomarkers and their characteristics is the key to precision medicine in intensive and perioperative care. Biomarkers can be used to diagnose, in assessment of disease severity, to stratify risk, to predict and guide clinical decisions, and to guide treatments and response to them. In this review, we will analyze what characteristics a biomarker should have and how to ensure its usefulness, and we will review the biomarkers that in our opinion can make their knowledge more useful to the reader in their clinical practice, with a future perspective. These biomarkers, in our opinion, are lactate, C-Reactive Protein, Troponins T and I, Brain Natriuretic Peptides, Procalcitonin, MR-ProAdrenomedullin and BioAdrenomedullin, Neutrophil/lymphocyte ratio and lymphopenia, Proenkephalin, NefroCheck, Neutrophil gelatinase-associated lipocalin (NGAL), Interleukin 6, Urokinase-type soluble plasminogen activator receptor (suPAR), Presepsin, Pancreatic Stone Protein (PSP), and Dipeptidyl peptidase 3 (DPP3). Finally, we propose an approach to the perioperative evaluation of high-risk patients and critically ill patients in the Intensive Care Unit (ICU) based on biomarkers.

Relationship of Effective Circulating Volume with Sublingual Red Blood Cell Velocity and Microvessel Pressure Difference: A Clinical Investigation and Computational Fluid Dynamics Modeling

The characteristics of physiologic hemodynamic coherence are not well-investigated. We examined the physiological relationship between circulating blood volume, sublingual microcirculatory perfusion, and tissue oxygenation in anesthetized individuals with steady-state physiology. We assessed the correlation of mean circulatory filling pressure analogue (Pmca) with sublingual microcirculatory perfusion and red blood cell (RBC) velocity using SDF+ imaging and a modified optical flow-based algorithm. We also reconstructed the 2D microvessels and applied computational fluid dynamics (CFD) to evaluate the correlation of Pmca and RBC velocity with the obtained pressure and velocity fields in microvessels from CFD (pressure difference, (Δp)). Twenty adults with a median age of 39.5 years (IQR 35.5−44.5) were included in the study. Sublingual velocity distributions were similar and followed a log-normal distribution. A constant Pmca value of 14 mmHg was observed in all individuals with sublingual RBC velocity 6−24 μm s−1, while a Pmca < 14 mmHg was observed in those with RBC velocity > 24 μm s−1. When Pmca ranged between 11 mmHg and 15 mmHg, Δp fluctuated between 0.02 Pa and 0.1 Pa. In conclusion, the intact regulatory mechanisms maintain a physiological coupling between systemic hemodynamics, sublingual microcirculatory perfusion, and tissue oxygenation when Pmca is 14 mmHg.

Circulating suPAR associates with severity and in-hospital progression of COVID-19

BACKGROUND

COVID-19 disease progression is characterized by hyperinflammation and risk stratification may aid in early aggressive treatment and advanced planning. The aim of this study was to assess whether suPAR and other markers measured at hospital admission can predict the severity of COVID-19.

METHODS

The primary outcome measure in this international, multi-centre, prospective, observational study with adult patients hospitalized primarily for COVID-19 was the association of WHO Clinical Progression Scale (WHO-CPS) with suPAR, ferritin, CRP, albumin, LDH, eGFR, age, procalcitonin, and interleukin-6. Admission plasma suPAR levels were determined using the suPARnostic^® ELISA and suPARnostic^® Turbilatex assays.

RESULTS

Seven hundred and sixty-seven patients, 440 (57.4%) males and 327 (42.6%) females, were included with a median age of 64 years. Log-suPAR levels significantly correlated with WHO-CPS score, with each doubling of suPAR increasing the score by one point (p < .001). All the other markers were also correlated with WHO-CPS score. Admission suPAR levels were significantly lower in survivors (7.10 vs. 9.63, 95% CI 1.47-3.59, p < .001). A linear model (SALGA) including suPAR, serum albumin, serum lactate dehydrogenase, eGFR, and age can best estimate the WHO-CPS score and survival. Combining all five parameters in the SALGA model can improve the accuracy of discrimination with an AUC of 0.80 (95% CI: 0.759-0.836).

CONCLUSIONS

suPAR levels significantly correlated with WHO-CPS score, with each doubling of suPAR increasing the score by one point. The SALGA model may serve as a quick tool for predicting disease severity and survival at admission.

Association of Preoperative Basal Inflammatory State, Measured by Plasma suPAR Levels, with Intraoperative Sublingual Microvascular Perfusion in Patients Undergoing Major Non-Cardiac Surgery

It remains unknown whether chronic systemic inflammation is associated with impaired microvascular perfusion during surgery. We evaluated the association between the preoperative basal inflammatory state, measured by plasma soluble urokinase-type plasminogen activator receptor (suPAR) levels, and intraoperative sublingual microcirculatory variables in patients undergoing major non-cardiac surgery. Plasma suPAR levels were determined in 100 non-cardiac surgery patients using the suPARnostic® quick triage lateral flow assay. We assessed sublingual microcirculation before surgical incision and every 30 min during surgery using Sidestream Darkfield (SDF+) imaging and determined the De Backer score, the Consensus Proportion of Perfused Vessels (Consensus PPV), and the Consensus PPV (small). Elevated suPAR levels were associated with lower intraoperative De Backer score, Consensus PPV, and Consensus PPV (small). For each ng mL−1 increase in suPAR, De Backer score, Consensus PPV, and Consensus PPV (small) decreased by 0.7 mm−1, 2.5%, and 2.8%, respectively, compared to baseline. In contrast, CRP was not significantly correlated with De Backer score (r = −0.034, p = 0.36), Consensus PPV (r = −0.014, p = 0.72) or Consensus PPV Small (r = −0.037, p = 0.32). Postoperative De Backer score did not change significantly from baseline (5.95 ± 3.21 vs. 5.89 ± 3.36, p = 0.404), while postoperative Consensus PPV (83.49 ± 11.5 vs. 81.15 ± 11.8, p < 0.001) and Consensus PPV (small) (80.87 ± 13.4 vs. 78.72 ± 13, p < 0.001) decreased significantly from baseline. In conclusion, elevated preoperative suPAR levels were associated with intraoperative impairment of sublingual microvascular perfusion in patients undergoing elective major non-cardiac surgery.

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.