Assessment of tissue oxygenation to personalize mean arterial pressure target in patients with septic shock

The Eight Unanswered and Answered Questions about the Use of Vasopressors in Septic Shock

Septic shock is mainly characterized-in addition to hypovolemia-by vasoplegia as a consequence of a release of inflammatory mediators. Systemic vasodilatation due to depressed vascular tone results in arterial hypotension, which induces or worsens organ hypoperfusion. Accordingly, vasopressor therapy is mandatory to correct hypotension and to reverse organ perfusion due to hypotension. Currently, two vasopressors are recommended to be used, norepinephrine and vasopressin. Norepinephrine, an α₁-agonist agent, is the first-line vasopressor. Vasopressin is suggested to be added to norepinephrine in cases of inadequate mean arterial pressure instead of escalating the doses of norepinephrine. However, some questions about the bedside use of these vasopressors remain. Some of these questions have been well answered, some of them not clearly addressed, and some others not yet answered. Regarding norepinephrine, we firstly reviewed the arguments in favor of the choice of norepinephrine as a first-line vasopressor. Secondly, we detailed the arguments found in the recent literature in favor of an early introduction of norepinephrine. Thirdly, we reviewed the literature referring to the issue of titrating the doses of norepinephrine using an individualized resuscitation target, and finally, we addressed the issue of escalation of doses in case of refractory shock, a remaining unanswered question. For vasopressin, we reviewed the rationale for adding vasopressin to norepinephrine. Then, we discussed the optimal time for vasopressin administration. Subsequently, we addressed the issue of the optimal vasopressin dose, and finally we discussed the best strategy to wean these two vasopressors when combined.

Serum vascular endothelial growth factor affects tissue fluid accumulation and is associated with deteriorating tissue perfusion and oxygenation in severe sepsis: a prospective observational study

BACKGROUND

Positive fluid balance and tissue fluid accumulation are associated with adverse outcomes in sepsis. Vascular endothelial growth factor (VEGF) increases in sepsis, promotes vascular permeability, and may affect tissue fluid accumulation and oxygenation. We used near-infrared spectroscopy (NIRS) to estimate tissue hemoglobin (Hb) oxygenation and water (H₂O) levels to investigate their relationship with serum VEGF levels.

MATERIAL AND METHODS

New-onset severe sepsis patients admitted to the intensive care unit were enrolled. Relative tissue concentrations of oxy-Hb ([HbO₂]), deoxy-Hb ([HbR]), total Hb ([HbT]), and H₂O ([H₂O]) were estimated by near-infrared spectroscopy (NIRS) for three consecutive days and serum VEGF levels were measured. Comparisons between oliguric and non-oliguric patients were conducted and the correlations between variables were analyzed.

RESULTS

Among 75 eligible patients, compared with non-oliguric patients, oliguric patients were administrated more intravascular fluids (median [IQR], 1926.00 [1348.50-3092.00] mL/day vs. 1069.00 [722.00-1486.75] mL/day, p < 0.001) and had more positive daily net intake and output (mean [SD], 1,235.06 [1303.14] mL/day vs. 313.17 [744.75] mL/day, p = 0.012), lower [HbO₂] and [HbT] over the three-day measurement (analyzed by GEE p = 0.01 and 0.043, respectively) and significantly higher [H₂O] on the third day than on the first two days (analyzed by GEE p = 0.034 and 0.018, respectively). Overall, serum VEGF levels were significantly negatively correlated with [HbO₂] and [HbT] (rho = - 0.246 and - 0.266, p = 0.042 and 0.027, respectively) but positively correlated with [H₂O] (rho = 0.449, p < 0.001). Subgroup analysis revealed a significant correlation between serum VEGF and [H2O] in oliguric patients (rho = 0.532, p = 0.003). Multiple regression analysis determined the independent effect of serum VEGF on [H₂O] (standardized coefficient = 0.281, p = 0.038).

CONCLUSIONS

In severe sepsis, oliguria relates to higher positive fluid balance, lower tissue perfusion and oxygenation, and progressive tissue fluid accumulation. Elevated serum VEGF is associated with worsening tissue perfusion and oxygenation and independently affects tissue fluid accumulation.

New Hemodynamic Parameters in Peri-Operative and Critical Care-Challenges in Translation

Hemodynamic monitoring technologies are evolving continuously-a large number of bedside monitoring options are becoming available in the clinic. Methods such as echocardiography, electrical bioimpedance, and calibrated/uncalibrated analysis of pulse contours are becoming increasingly common. This is leading to a decline in the use of highly invasive monitoring and allowing for safer, more accurate, and continuous measurements. The new devices mainly aim to monitor the well-known hemodynamic variables (e.g., novel pulse contour, bioreactance methods are aimed at measuring widely-used variables such as blood pressure, cardiac output). Even though hemodynamic monitoring is now safer and more accurate, a number of issues remain due to the limited amount of information available for diagnosis and treatment. Extensive work is being carried out in order to allow for more hemodynamic parameters to be measured in the clinic. In this review, we identify and discuss the main sensing strategies aimed at obtaining a more complete picture of the hemodynamic status of a patient, namely: (i) measurement of the circulatory system response to a defined stimulus; (ii) measurement of the microcirculation; (iii) technologies for assessing dynamic vascular mechanisms; and (iv) machine learning methods. By analyzing these four main research strategies, we aim to convey the key aspects, challenges, and clinical value of measuring novel hemodynamic parameters in critical care.

Effects of mean arterial pressure target on mottling and arterial lactate normalization in patients with septic shock: a post hoc analysis of the SEPSISPAM randomized trial

Background

In patients with septic shock, the impact of the mean arterial pressure (MAP) target on the course of mottling remains uncertain. In this post hoc analysis of the SEPSISPAM trial, we investigated whether a low-MAP (65 to 70 mmHg) or a high-MAP target (80 to 85 mmHg) would affect the course of mottling and arterial lactate in patients with septic shock.

Methods

The presence of mottling was assessed every 2 h from 2 h after inclusion to catecholamine weaning. We compared mottling and lactate time course between the two MAP target groups. We evaluated the patient’s outcome according to the presence or absence of mottling.

Results

We included 747 patients, 374 were assigned to the low-MAP group and 373 to the high-MAP group. There was no difference in mottling and lactate evolution during the first 24 h between the two MAP groups. After adjustment for MAP and confounding factors, the presence of mottling ≥ 6 h during the first 24 h was associated with a significantly higher risk of death at day 28 and 90. Patients without mottling or with mottling < 6 h and lactate ≥ 2 mmol/L have a higher probability of survival than those with mottling ≥ 6 h and lactate < 2 mmol/L.

Conclusion

Compared with low MAP target, higher MAP target did not alter mottling and lactate course. Mottling lasting for more than 6 h was associated with higher mortality. Compared to arterial lactate, mottling duration appears to be a better marker of mortality.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-01053-1.

Vasopressors and Risk of Acute Mesenteric Ischemia: A Worldwide Pharmacovigilance Analysis and Comprehensive Literature Review

Vasodilatory shock, such as septic shock, requires personalized management which include adequate fluid therapy and vasopressor treatments. While these potent drugs are numerous, they all aim to counterbalance the vasodilatory effects of a systemic inflammatory response syndrome. Their specific receptors include α- and β-adrenergic receptors, arginine-vasopressin receptors, angiotensin II receptors and dopamine receptors. Consequently, these may be associated with severe adverse effects, including acute mesenteric ischemia (AMI). As the risk of AMI depends on drug class, we aimed to review the evidence of plausible associations by performing a worldwide pharmacovigilance analysis based on the World Health Organization database, VigiBase®. Among 24 million reports, 104 AMI events were reported, and disproportionality analyses yielded significant association with all vasopressors, to the exception of selepressin. Furthermore, in a comprehensive literature review, we detailed mechanistic phenomena which may enhance vasopressor selection, in the course of treating vasodilatory shock.