Microcirculatory alterations in shock states

The role of lactate-to-albumin ratio to predict 30-day risk of death in patients with sepsis in the emergency department: a decision tree analysis

BACKGROUND

Accurately estimating the prognosis of septic patients on arrival in the emergency department (ED) is clinically challenging. The lactate-to-albumin ratio (LAR) has recently been proposed to improve the predictive performance of septic patients admitted to the ICU.

OBJECTIVES

This study aims to assess whether the LAR could be used as an early prognostic marker of 30-day mortality in patients with sepsis in the ED.

METHODS

A prospective observational study was conducted in the ED of the Hospital of Merano. All patients with a diagnosis of sepsis were considered. The LAR was recorded on arrival in the ED. The primary outcome measure was mortality at 30 days. The predictive role of the LAR for mortality was evaluated with the area under the ROC curve, logistic regression adjusted for the Charlson Comorbidity Index value, National Early Warning Score, and Sequential Organ Failure score, and with decision tree analysis.

RESULTS

459 patients were enrolled, of whom 17% (78/459) died at 30 days. The median LAR of the patients who died at 30 days (0.78 [0.45-1.19]) was significantly higher than the median LAR of survivors (0.42 [0.27-0.65]) (p < 0.001). The discriminatory ability of the LAR for death at 30 days was 0.738, higher than that of lactate alone (0.692), and slightly lower than that of albumin alone (0.753). The decision trees confirmed the role of the LAR as an independent risk factor for mortality.

CONCLUSION

The LAR can be used as an index to better predict the 30-day risk of death in septic patients.

Non-invasive assessment of sublingual microcirculation using flow derived from green light PPG: evaluation and reference values

Significance

The study of sublingual microcirculation offers valuable insights into vascular changes and overcomes some limitations of peripheral microcirculation assessment. Videomicroscopy and pulse oximetry have been used to assess microcirculation, providing insights into organ perfusion beyond macrohemodynamics parameters. However, both techniques have important limitations that preclude their use in clinical practice.

Aim

To address this, we propose a non-invasive approach using photoplethysmography (PPG) to assess microcirculation.

Approach

Two experiments were performed on different samples of 31 subjects. First, multi-wavelength, finger PPG signals were compared before and while applying pressure on the sensor to determine if PPG signals could detect changes in peripheral microcirculation. For the second experiment, PPG signals were acquired from the ventral region of the tongue, aiming to assess the microcirculation through features calculated from the PPG signal and its first derivative.

Results

In experiment 1, 13 out of 15 features extracted from green PPG signals showed significant differences (p < 0.05 ) before and while pressure was applied to the sensor, suggesting that green light could detect flow distortion in superficial capillaries. In experiment 2, 15 features showed potential application of PPG signal for sublingual microcirculation assessment.

Conclusions

The PPG signal and its first derivative have the potential to effectively assess microcirculation when measured from the fingertip and the tongue. The assessment of sublingual microcirculation was done through the extraction of 15 features from the green PPG signal and its first derivative. Future studies are needed to standardize and gain a deeper understanding of the evaluated features.

Imaging sublingual microcirculatory perfusion in pediatric patients receiving procedural sedation with propofol: A pilot study

Objective

Procedural sedation with propofol is widely used in the pediatric population. A well‐known side effect of propofol is a decrease in peripheral vascular resistance resulting in hypotension, but little is known about the effects on microcirculation in humans. We aimed to evaluate the effects of propofol on the sublingual microcirculatory perfusion by continuous video imaging in pediatric patients undergoing procedural sedation.

Methods

Patients admitted to the Pediatric Intensive Care Unit for procedural sedation were recruited. Oral microcirculation was measured employing a continuous monitoring strategy with incident dark‐field illumination imaging. Measurements were obtained before and 3 minutes after propofol induction. Total and perfused vessel densities, proportion of perfused vessels, microvascular flow index, blood vessel diameter (Ø_bv), and systemic hemodynamics were analyzed.

Results

Continuous measurements were achieved in seven patients. Three minutes after propofol induction mean arterial pressure decreased (P = 0.028) and total and perfused vessel densities increased by 12% (P = 0.018) and 16% (P = 0.018), respectively. MFI was unaltered and mean Ø_bv increased but not significantly.

Conclusions

Propofol induction induces a reduction in mean arterial pressure and a rise in sublingual microvascular perfusion. The observed effects of propofol on the sublingual microcirculation may be due to a decrease in microvascular resistance.

Effects of Ringer's sodium pyruvate solution on serum tumor necrosis factor-α and interleukin-6 upon septic shock

Objective:

To study the effects of Ringer’s sodium pyruvate solution on tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) upon septic shock.

Methods:

Ninety emergency patients with septic shock were divided into a treatment group and a control group by random draw. The control group was resuscitated with 50 ml of compound sodium chloride (Ringer’s solution), and the treatment group was given 50 ml of Ringer’s sodium pyruvate solution. Both groups were basically treated.

Results:

All patients were successfully resuscitated. After treatment, extravascular lung water index, intrathoracic blood volume index, systemic vascular resistance index and cardiac index of the two groups were significantly improved compared with those before treatment (P<0.05). However, there were no significant inter-group differences at different time points (P>0.05). Blood lactic acid level, central venous oxygen saturation index and urine output were also improved after treatment, with significant inter-group differences (P<0.05). Serum TNF-α and IL-6 levels of both groups significantly decreased after treatment (P<0.05), and the levels of the treatment group were significantly lower than those of the control group (P<0.05). During 28 days of follow-up, the mortality rate of the treatment group (4.4%) was significantly lower than that of the control group (20.0%) (P<0.05).

Conclusion:

Patients with septic shock are complicated with disordered expressions of inflammatory factors. During resuscitation, Ringer’s sodium pyruvate solution can effectively promote blood circulation, mitigate inflammation and maintain acid-base equilibrium, thus decreasing the prognostic mortality rate.