Effect of Increasing Blood Pressure With Noradrenaline on the Microcirculation of Patients With Septic Shock and Previous Arterial Hypertension

Prognostic evaluation of the norepinephrine equivalent score and the vasoactive-inotropic score in patients with sepsis and septic shock: a retrospective cohort study

Background

This study investigated the association between vasoactive medication exposure and mortality risk in patients with sepsis using the norepinephrine equivalent (NEE) score and vasoactive-inotropic score (VIS).

Methods

This retrospective cohort study included adult patients with sepsis requiring vasoactive agents. The data were extracted from the Medical Information Mart for Intensive Care IV database. The primary outcome was 28-day mortality. Multivariate Cox regression was used to elucidate the relationship between vasoactive medication exposure and 28-day mortality, as quantified by the VIS and NEE score. Hazard ratios with 95% confidence intervals (CI) for 28-day mortality were generated, and forest plots were constructed to present the results of univariate and multivariate analyses. The Kaplan-Meier method was used to analyze the cumulative incidence of 28-day mortality. A nomogram was constructed to predict the prognosis of patients with sepsis.

Results

The present study encompassed 9,032 patients diagnosed with sepsis who received vasoactive therapy, of which 4,229 patients were further analyzed at the second hour after the onset of sepsis. Distinct variations in demographic data were observed between survivors (n = 3,265, 77.21%) and non-survivors (n = 964, 22.79%). Multivariate analysis indicated that several factors, including VIS >15.04 (p = 0.001), NEE >0.10 (p < 0.001), heart rate (p = 0.045), mean arterial pressure (p = 0.009), respiratory rate (p < 0.001), oxygen saturation (p < 0.001), blood urea nitrogen (BUN) (p = 0.001), and the Acute Physiology and Chronic Health Evaluation II (p < 0.001), were significantly associated with 28-day mortality in the patients with sepsis. The NEE score, respiratory rate, oxygen saturation, and BUN were incorporated into the nomogram model with a concordance index of 0.779 and an area under the curve of 0.802 (95% CI 0.787-0.818).

Conclusion

We found that the VIS and NEE score had favorable values for predicting mortality risk in patients with sepsis in the intensive care units. The VIS and NEE score in the second hour after sepsis onset were independently associated with 28-day mortality in patients with sepsis.

Micro- and macrocirculatory effects of norepinephrine on anaesthesia-induced hypotension: a prospective preliminary study

BACKGROUND

Intraoperative arterial hypotension (IOH) leads to increased postoperative morbidity. Norepinephrine is often use to treat IOH. The question regarding the mode of administration in either a bolus or continuous infusion remains unanswered. The aim of the present study was to describe and compare the effects on macrocirculation and microcirculation of a bolus and a continuous infusion of norepinephrine to treat IOH.

METHODS

We conducted a prospective observational study with adult patients who underwent neurosurgery. Patients with invasive arterial blood pressure and cardiac output (CO) monitoring were screened for inclusion. All patients underwent microcirculation monitoring by video-capillaroscopy, laser doppler, near-infrared spectroscopy technology, and tissular CO2. In case of IOH, the patient could receive either a bolus of 10 µg or a continuous infusion of 200 µg/h of norepinephrine. Time analysis for comparison between bolus and continuous infusion were at peak of MAP. The primary outcome was MFI by videocapillaroscopy.

RESULTS

Thirty-five patients were included, with 41 boluses and 33 continuous infusion. Bolus and continuous infusion induced an maximal increase in mean arterial pressure of +30[20-45] and +23[12-34] %, respectively (P=0,07). For macrocirculatory parameters, continuous infusion was associated with a smaller decrease in CO and stroke volume (p<0.05). For microcirculatory parameters, microvascular flow index (-0,1 vs. + 0,3, p=0,03), perfusion index (-12 vs. +12%, p=0,008), total vessel density (-0,2 vs. +2,3 mm2/mm2, p=0,002), showed significant opposite variations with bolus and continuous infusion, respectively.

CONCLUSIONS

These results on macro and microcirculation enlighten the potential benefits of a continuous infusion of norepinephrine rather than a bolus to treat anaesthesia-induced hypotension.

TRIAL REGISTRATION

(NOR-PHARM: 1-17-42 Clinical Trials: NCT03454204), 05/03/2018.

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.

Novelties in the evaluation of microcirculation in septic shock

Microvascular alterations were first described in critically ill patients about 20 years ago. These alterations are characterized by a decrease in vascular density and presence of non-perfused capillaries close to well-perfused vessels. In addition, heterogeneity in microvascular perfusion is a key finding in sepsis. In this narrative review, we report our actual understanding of microvascular alterations, their role in the development of organ dysfunction, and the implications for outcome. Herein, we discuss the state of the potential therapeutic interventions and the potential impact of novel therapies. We also discuss how recent technologic development may affect the evaluation of microvascular perfusion.

Effects of perioperative dexmedetomidine infusion on renal function and microcirculation in kidney transplant recipients: a randomised controlled trial

OBJECTIVE

Ischemia-reperfusion injury affects postoperative transplanted kidney function in kidney transplant recipients. Dexmedetomidine was reported to attenuate ischemia-reperfusion injury and improve microcirculation, but its propensity to cause bradycardia and hypotension may adversely affect microcirculation. This study investigated the effect of dexmedetomidine on postoperative renal function and sublingual microcirculation in kidney recipients.

METHODS

The enrolled kidney transplant recipients were randomly allocated to the control group or dexmedetomidine group. After anaesthesia induction, patients in the dexmedetomidine group received dexmedetomidine infusion until 2 h after surgery. Sublingual microcirculation was recorded using an incident dark-field video microscope and analysed. The primary outcomes were the creatinine level on a postoperative day 2 and total vessel density at 2 h after surgery.

RESULTS

A total of 60 kidney recipients were analysed, and the creatinine levels on postoperative day 2 were significantly lower in the dexmedetomidine group than in the control group (1.5 (1.1-2.4) vs. 2.2 (1.7-3.0) mg/dL, median difference -0.6 (95% CI, -0.7 to -0.5) mg/dL, p = .018). On a postoperative day 7, the creatinine levels did not differ significantly between the two groups. Total vessel density at 2 h after surgery did not differ significantly between the two groups.

CONCLUSION

We found that early postoperative renal function was better in kidney transplant recipients receiving dexmedetomidine infusion, but total vessel density was not significantly different between the intervention and control groups. Key messagesIschemia-reperfusion injury affects postoperative transplanted kidney function, and dexmedetomidine was reported to attenuate ischemia-reperfusion injury and improve microcirculation in other clinical conditions.This study showed that early postoperative renal function was better in kidney transplant recipients receiving dexmedetomidine.Dexmedetomidine's side effect of bradycardia and hypotension may affect microcirculation, our results revealed that the perioperative sublingual microcirculation did not differ significantly in kidney transplant recipients receiving dexmedetomidine.

Optimal target blood pressure in elderly with septic shock (OPTPRESS) trial: study protocol for a randomized controlled trial

Background

Hemodynamic stabilization is a core component in the resuscitation of septic shock. However, the optimal target blood pressure remains debatable. Previous randomized controlled trials suggested that uniformly adopting a target mean arterial pressure (MAP) higher than 65 mmHg for all adult septic shock patients would not be beneficial; however, it has also been proposed that higher target MAP may be beneficial for elderly patients, especially those with arteriosclerosis.

Methods

A multicenter, pragmatic single-blind randomized controlled trial will be conducted to compare target MAP of 80–85 mmHg (high-target) and 65–70 mmHg (control) in the resuscitation of septic shock patients admitted to 28 hospitals in Japan. Patients with septic shock aged ≥65 years are randomly assigned to the high-target or control groups. The target MAP shall be maintained for 72 h after randomization or until vasopressors are no longer needed to improve patients’ condition. To minimize the adverse effects related to catecholamines, if norepinephrine dose of ≥ 0.1 μg/kg/min is needed to maintain the target MAP, vasopressin will be initiated. Other therapeutic approaches, including fluid administration, hydrocortisone use, and antibiotic choice, will be determined by the physician in charge based on the latest clinical guidelines. The primary outcome is all-cause mortality at 90 days after randomization.

Discussion

The result of this trial will provide great insight on the resuscitation strategy for septic shock in the era of global aged society. Also, it will provide the better understanding on the importance of individualized treatment strategy in hemodynamic management in critically ill patients.

Trial registration

UMIN Clinical Trials Registry; UMIN000041775. Registered 13 September 2020.

Optimal target blood pressure in critically ill adult patients with vasodilatory shock: A systematic review and meta-analysis

While the Surviving Sepsis Campaign guidelines recommend an initial target value of 65 mmHg as the mean arterial pressure (MAP) in patients with septic shock, the optimal MAP target for improving outcomes remains controversial. We performed a meta-analysis to evaluate the optimal MAP for patients with vasodilatory shock, which included three randomized controlled trials that recruited 3,357 patients. Between the lower (60–70 mmHg) and higher (>70 mmHg) MAP target groups, there was no significant difference in all-cause mortality (risk ratio [RR], 1.06; 95% confidence intervals [CI], 0.98–1.16) which was similar in patients with chronic hypertension (RR, 1.10; 95% CI, 0.98–1.24) and patients aged ≥65 years (RR, 1.10; 95% CI, 0.99–1.21). No significant difference in adverse events was observed between the different MAP groups (RR, 1.04; 95% CI, 0.87–1.24); however, supraventricular arrhythmia was significantly higher in the higher MAP group (RR, 1.73; 95% CI, 1.15–2.60). Renal replacement therapy was reduced in the higher MAP group of patients with chronic hypertension (RR, 0.83; 95% CI, 0.71–0.98). Though the higher MAP control did not improve the mortality rate, it may be beneficial in reducing renal replacement therapy in patients with chronic hypertension.

Systematic review registration: UMIN Clinical Trials Registry, identifier UMIN000042624

Circular RNA UBAP2 (hsa_circ_0007367) Correlates with Microcirculatory Perfusion and Predicts Outcomes of Cardiogenic Shock Patients Undergoing Extracorporeal Membrane Oxygenation Support

BACKGROUND

Severe microcirculatory disturbance is common in patients with cardiogenic shock necessitating extracorporeal membrane oxygenation (ECMO), however, biomarkers linked to microcirculation and clinical outcome are scarce. Herein we identified a circular RNA, hsa_circ_0007367, rooted from the ubiquitin-associated protein 2 (UBAP2) gene, namely circUBAP2, and evaluated its biological function and the associations with microcirculation and the prognosis.

METHODS

Patients on ECMO with cardiogenic shock were included if qualified sublingual microcirculation parameters could be obtained and were categorized into the survivor group or non-survivor group. Macro-circulatory, microcirculatory data, cytokine levels, and relative circUBAP2 expressions were collected before, at 24 h, and at ECMO weaning off, respectively. The effects of circUBAP2 on the migration, polarization, cytokine productions, and inflammatory pathways in macrophage NR8383 cells were investigated using in vitro methods.

RESULTS

Thirty-three patients with an average age of 58.0 years were enrolled, including 19 survivors and 14 non-survivors. The survivors had higher small vessel density, perfused small vessel density (PSVD), and microvascular flow index (MFI) throughout the ECMO course than did the non-survivors. Relative expression of circUBAP2 (hsa_circ_0007367) correlated with the microcirculatory parameters and satisfactorily predicted the 30-day in-hospital mortality. A multivariable logistic model was developed, showing following four predictors: age (odds ratio [OR] 1.06, 95% confidence interval [CI] 1.00-1.12), time from shock to ECMO (OR 1.10, 95% CI 1.01-1.20), PVSD (OR 0.14, 95% CI 0.02-0.89), and the circUBAP2 expression (OR 0.25, 95% CI 0.08-0.78). In addition, circUBAP2 inhibited the migratory activity and promoted M2 polarization in macrophages, declining the productions of cytokines (tumor necrosis factor [TNF]-α, interleukin [IL]-1β, and monocyte chemotactic protein [MCP]-1) and the PI3K/Akt/mTOR pathway.

CONCLUSION

The expression of circUBAP2 correlates with microcirculatory perfusion and has the potential in predicting outcomes for on-ECMO patients with cardiogenic shock.

Vasopressors in Septic Shock: The Quest for Refinement

How to cite this article: Pichamuthu K. Vasopressors in Septic Shock: The Quest for Refinement. Indian J Crit Care Med 2022;26(6):659–660.

Current practice and evolving concepts in septic shock resuscitation

Clinical and pathophysiological understanding of septic shock has progressed exponentially in the previous decades, translating into a steady decrease in septic shock-related morbidity and mortality. Even though large randomized, controlled trials have addressed fundamental aspects of septic shock resuscitation, many questions still exist. In this review, we will describe the current standards of septic shock resuscitation, but the emphasis will be placed on evolving concepts in different domains such as clinical resuscitation targets, adequate use of fluids and vasoactive drugs, refractory shock, and the use of extracorporeal therapies. Multiple research opportunities remain open, and collaborative endeavors should be performed to fill in these gaps.

Optimal target blood pressure in critically ill adult patients with vasodilatory shock: a protocol for a systematic review and meta-analysis

INTRODUCTION

The optimal target of mean arterial pressure (MAP) for better outcomes in patients with vasodilatory shock remains a matter of debate. Although catecholamines are generally used to maintain target blood pressure in hypotensive patients with vasodilatory shock, the adverse effects of catecholamines must also be considered. We will perform a systematic review and meta-analysis of randomised controlled trials (RCTs) to assess the certainty of evidence determining the optimal target of MAP control for patients with vasodilatory shock in critically ill settings.

METHODS AND ANALYSIS

This study protocol was registered in the University Hospital Medical Information Network Clinical Trials Registry. We will include only RCTs that evaluated the two different comparators for target MAP to be maintained for clinical outcomes of all-cause mortality: organ dysfunction and adverse events in critically ill adult patients with vasodilatory shock. We will search the electronic bibliographic databases of MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials in November 2020. Two reviewers will independently screen titles and abstracts, perform full article reviews and extract study data. We will report study characteristics and assess methodological quality using the Cochrane Risk-of-Bias 2 tool. If pooling is appropriate, we will calculate relative risks with 95% CIs for all outcome measures. Clinical and methodological subgroup and sensitivity analyses will be performed to explore heterogeneity. Overall certainty of evidence will be evaluated using the Grading of Recommendations Assessment, Development and Evaluation approach.

ETHICS AND DISSEMINATION

This study will not involve primary data collection, and formal ethics approval will therefore not be required. We aim to publish this systematic review in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

UMIN000042624.

Severe Impairment of Microcirculatory Perfused Vessel Density Is Associated With Postoperative Lactate and Acute Organ Injury After Cardiac Surgery

OBJECTIVE

Resuscitation after cardiac surgery needs to address multiple pathophysiological processes that are associated with significant morbidity and mortality. Functional microcirculatory derangements despite normal systemic hemodynamics have been previously described but must be tied to clinical outcomes. The authors hypothesized that microcirculatory dysfunction after cardiac surgery would include impaired capillary blood flow and impaired diffusive capacity and that subjects with the lowest quartile of perfused vessel density would have an increased postoperative lactate level and acute organ injury scores.

DESIGN

Prospective, observational study.

SETTING

A single, tertiary university cardiovascular surgical intensive care unit.

PARTICIPANTS

25 adults undergoing elective cardiac surgery requiring cardiopulmonary bypass.

INTERVENTION

Sublingual microcirculation was imaged using incident dark field microscopy before and 2 to 4 hours after surgery in the intensive care unit.

MEASUREMENTS AND MAIN RESULTS

Compared with baseline measurements, postoperative vessel-by-vessel microvascular flow index (2.9 [2.8-2.9] v 2.5 [2.4-2.7], p < 0.0001) and perfused vessel density were significantly impaired (20.7 [19.3-22.9] v 16.3 [12.8-17.9], p < 0.0001). The lowest quartile of perfused vessel density (<12.8 mm/mm2) was associated with a significantly increased postoperative lactate level (6.0 ± 2.9 v 1.8 ± 1.2, p < 0.05), peak lactate level (7.6 ± 2.8 v 2.8 ± 1.5, p = 0.03), and sequential organ failure assessment (SOFA) score at 24 and 48 hours.

CONCLUSION

In patients undergoing cardiac surgery, there was a significant decrease in postoperative microcirculatory convective blood flow and diffusive capacity during early postoperative resuscitation. Severely impaired perfused vessel density, represented by the lowest quartile of distribution, is significantly related to hyperlactatemia and early organ injury.

Monitoring Microcirculation: Utility and Barriers - A Point-of-View Review

Microcirculation is a particular organ of the cardiovascular system. The goal of this narrative review is a critical reappraisal of the present knowledge of microcirculation monitoring, mainly focused on the videomicroscopic evaluation of sublingual microcirculation in critically ill patients. We discuss the technological developments in handheld videomicroscopy, which have resulted in adequate tools for the bedside monitoring of microcirculation. By means of these techniques, a large body of evidence has been acquired about the role of microcirculation in the pathophysiological mechanisms of shock, especially septic shock. We review the characteristics of sublingual microcirculation in septic shock, which mainly consist in a decrease in the perfused vascular density secondary to a reduction in the proportion of perfused vessels along with a high heterogeneity in perfusion. Even in patients with high cardiac output, red blood cell velocity is decreased. Thus, hyperdynamic flow is absent in the septic microcirculation. We also discuss the dissociation between microcirculation and systemic hemodynamics, particularly after shock resuscitation, and the different behavior among microvascular beds. In addition, we briefly comment the effects of some treatments on microcirculation. Despite the fact that sublingual microcirculation arises as a valuable goal for the resuscitation in critically ill patients, significant barriers remain present for its clinical application. Most of them are related to difficulties in video acquisition and analysis. We comprehensively analyzed these shortcomings. Unfortunately, a simpler approach, such as the central venous minus arterial PCO₂ difference, is a misleading surrogate for sublingual microcirculation. As conclusion, the monitoring of sublingual microcirculation is an appealing method for monitoring critically ill patients. Nevertheless, the lack of controlled studies showing benefits in terms of outcome, as well as technical limitations for its clinical implementation, render this technique mainly as a research tool.

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

OBJECTIVE

To investigate whether assessment of tissue oxygenation could help personalizing the mean arterial pressure (MAP) target in patients with septic shock.

METHODS

We prospectively measured near-infrared spectroscopy variables in 22 patients with septic shock receiving norepinephrine with a MAP>75 mmHg within the first six hours of intensive care unit (ICU) stay for patients with community-acquired septic shock and within the first six hours of resuscitation for patients with ICU-acquired septic shock. All measurements were performed at MAP>75 mmHg ("high-MAP") and at MAP 65-70 mmHg ("low-MAP") after decreasing the norepinephrine dose. Relative changes in StO₂ recovery slope (RS) >8% were considered clinically relevant.

RESULTS

After decreasing the norepinephrine dose by 45 ± 24%, MAP significantly decreased from 81[78;84] to 68[67;69]mmHg, whereas cardiac index did not change. On average, the StO₂-RS significantly decreased between high and low-MAP from 2.86[1.87;4.32] to 2.41[1.14;3.72]%/sec with a large interindividual variability: the StO₂-RS decreased by >8% in 14 patients, increased by >8% in 4 patients and changes were < 8% in 4 patients. These changes in StO₂-RS were correlated with the StO₂-RS at low-MAP (r = 0.57,p = 0.006). At high-MAP, there was no difference between patients exhibiting a relevant decrease or increase in StO₂-RS.

CONCLUSIONS

A unique MAP target may not be suitable for all patients with septic shock as its impact on peripheral oxygenation may widely differ among patients. It could make sense to personalize MAP target through a multimodal assessment including peripheral oxygenation.

Vasopressors in septic shock: which, when, and how much?

In addition to fluid resuscitation, the vasopressor therapy is a fundamental treatment of septic shock-induced hypotension as it aims at correcting the vascular tone depression and then at improving organ perfusion pressure. Experts’ recommendations currently position norepinephrine (NE) as the first-line vasopressor in septic shock. Vasopressin and its analogues are only second-line vasopressors as strong recent evidence suggests no benefit of their early administration in spite of promising preliminary data. Early administration of NE may allow achieving the initial mean arterial pressure (MAP) target faster and reducing the risk of fluid overload. The diastolic arterial pressure (DAP) as a marker of vascular tone, helps identifying the patients who need NE urgently. Available data suggest a MAP of 65 mmHg as the initial target but a more individualized approach is often required depending on several factors such as history of chronic hypertension or value of central venous pressure (CVP). In cases of refractory hypotension, increasing NE up to doses ≥1 µg/kg/min could be an option. However, current experts’ guidelines suggest to combine NE with other vasopressors such as vasopressin, with the intent to rising the MAP to target or to decrease the NE dosage.

Early norepinephrine use in septic shock

As vascular tone depression is a hallmark of septic shock, administration of norepinephrine is logical in this setting. In this article, we provide and develop the following arguments for an early use of norepinephrine-the recommended first-line vasopressor-in septic shock: (I) prevention of prolonged severe hypotension, (II) increase in cardiac output through an increase in cardiac preload and/or contractility, (III) improvement of microcirculation and tissue oxygenation, (IV) prevention of fluid overload, and (V) improvement of outcome. Presence of a low diastolic arterial pressure as a marker of depressed vascular tone can be used as a trigger to initiate norepinephrine urgently.

From a pressure-guided to a perfusion-centered resuscitation strategy in septic shock: Critical literature review and illustrative case

PURPOSE

To support a paradigm shift in the management of septic shock from pressure-guided to perfusion-centered, expected to improve outcome while reducing adverse effects from vasopressor therapy and aggressive fluid resuscitation.

MATERIAL AND METHODS

Critical review of the literature cited in support of vasopressor use to achieve a predefined mean arterial pressure (MAP) of 65 mmHg and review of pertinent clinical trials and studies enabling deeper understanding of the hemodynamic pathophysiology supportive of a perfusion-centered approach, accompanied by an illustrative case.

RESULTS

Review of the literature cited by the Surviving Sepsis Campaign revealed lack of controlled clinical trials supporting outcome benefits from vasopressors. Additional literature review revealed adverse effects associated with vasopressors and worsened outcome in some studies. Vasopressors increase MAP primarily by peripheral vasoconstriction and in occasions by a modest increase in cardiac output when using norepinephrine. Thus, achieving the recommended MAP of 65 mmHg using vasopressors should not be presumed indicative that organ perfusion has been restored. It may instead create a false sense of hemodynamic stability hampering shock resolution.

CONCLUSIONS

We propose focusing the hemodynamic management of septic shock on reversing organ hypoperfusion instead of attaining a predefined MAP target as the key strategy for improving outcome.