Outcome of patients with septic shock and high-dose vasopressor therapy

Exploration of Norepinephrine Dose-Capping Practices: Report From an International, Interprofessional Survey of Critical Care Clinicians

Purpose: The Joint Commission standards for titrated infusions require specification of maximum rates of infusion. This practice has led to the development of protocolized maximum doses that can be overridden by provider order ("soft maximums") and to dose caps that cannot be superseded ("hard maximums"). The purpose of this study was to determine the prevalence of and attitudes towards dose capping of norepinephrine. Methods: A 20-item cross-sectional survey assessing norepinephrine dose capping practices, perceptions of norepinephrine protocols, and respondent and practice site demographics was distributed electronically to the mailing list of an international medical podcast. Responses were stratified according to use of weight-based dosing (WBD) or non-WBD of norepinephrine. The primary objective was to characterize norepinephrine dosing practices including protocolized maximum doses and/or dose capping. Categorical and continuous variables were compared using the Chi-square test and Mann-Whitney U test, respectively, with P < .05 indicating statistical significance. Results: The survey was completed by 586 physicians, nurses, pharmacists, and advanced practice providers. WBD was used by 51% and non-WBD by 47%. A standardized titration protocol was reported by 65% and dose capping was reported by 19%. The protocolized maximum dose ranged from 20-400 mcg/min for respondents using non-WBD (median [interquartile range] 30 [30-50]) and ranged from .2-10 mcg/kg/min for respondents using WBD (1 [.5-3]). The dose cap was 50 (40-123) mcg/min with non-WBD and 2 (1-3) mcg/kg/min with WBD. Conclusions: An international, multi-professional survey of critical care and emergency medicine clinicians revealed wide variability in norepinephrine dosing practices including maximum doses allowed.

Noradrenaline dose cutoffs to characterise the severity of cardiovascular failure: Data-based development and external validation

BACKGROUND

The vasopressor dose needed is a common measure to assess the severity of cardiovascular failure, but there is no consensus on the ranges of vasopressor doses determining different levels of cardiovascular support. We aimed to identify cutoffs for determining low, intermediate and high doses of noradrenaline (norepinephrine), the primary vasopressor used in intensive care, based on association with hospital mortality.

METHODS

We conducted a binational registry study to determine cutoffs between low, intermediate and high noradrenaline doses. We required the cutoffs to be statistically rational and practical (rounded to the first decimal and easy to remember), and to result in increasing mortality with increasing doses. The highest noradrenaline dose in the first 24 h after intensive care unit (ICU) admission was used. The cutoffs were developed using data from 8079 ICU patients treated in the ICU at Kuopio University Hospital, Finland, between 2013 and 2019. Subsequently, the cutoffs were validated in the eICU database, including 39,007 ICU admissions to 29 ICUs in the United States of America in 2014-2015. The log-rank statistic, with the Contal and O'Quigley method, was used to determine the cutoffs resulting in the most significant split between the noradrenaline dose groups with regard to hospital mortality.

RESULTS

The two most prominent peaks in the log-rank statistic corresponded to noradrenaline doses 0.20 and 0.44 μg/kg/min. Accordingly, we determined three dose ranges: low (<0.2 μg/kg/min), intermediate (0.2-0.4 μg/kg/min) and high (>0.4 μg/kg/min). Mortality increased, whereas the number of patients decreased consistently with increasing noradrenaline doses in both cohorts. In the development cohort, hospital mortality was 6.5% in the group without noradrenaline administered and 14.0%, 26.4% and 40.2%, respectively, in the low-dose, intermediate-dose and high-dose groups. Compared to patients who received no noradrenaline, the hazard ratio for in-hospital death was 1.4 for the low-dose group, 4.0 for the intermediate-dose group and 7.5 for the high-dose group in the validation cohort (p < .001).

CONCLUSIONS

The highest noradrenaline dose is a useful measure for quantifying circulatory failure. Cutoffs 0.2 and 0.4 μg/kg/min seem to be suitable for defining low, intermediate and high doses.

Effects of dynamic versus static parameter-guided fluid resuscitation in patients with sepsis: A randomized controlled trial

Background

Fluid resuscitation is an essential component for sepsis treatment. Although several studies demonstrated that dynamic variables were more accurate than static variables for prediction of fluid responsiveness, fluid resuscitation guidance by dynamic variables is not standard for treatment. The objectives were to determine the effects of dynamic inferior vena cava (IVC)-guided versus (vs.) static central venous pressure (CVP)-guided fluid resuscitation in septic patients on mortality; and others, i.e., resuscitation targets, shock duration, fluid and vasopressor amount, invasive respiratory support, length of stay and adverse events.

Methods

A single-blind randomized controlled trial was conducted at Thammasat University Hospital between August 2016 and April 2020. Septic patients were stratified by acute physiologic and chronic health evaluation II (APACHE II) <25 or ≥25 and randomized by blocks of 2 and 4 to fluid resuscitation guidance by dynamic IVC or static CVP.

Results

Of 124 patients enrolled, 62 were randomized to each group, and one of each was excluded from mortality analysis. Baseline characteristics were comparable. The 30-day mortality rates between dynamic IVC vs. static CVP groups were not different (34.4% vs. 45.9%, p=0.196). Relative risk for 30-day mortality of dynamic IVC group was 0.8 (95%CI=0.5-1.2, p=0.201). Different outcomes were median (interquartile range) of shock duration (0.8 (0.4-1.6) vs. 1.5 (1.1-3.1) days, p=0.001) and norepinephrine (NE) dose (6.8 (3.9-17.8) vs. 16.1 (7.6-53.6) milligrams, p=0.008 and 0.1 (0.1-0.3) vs. 0.3 (0.1-0.8) milligram⋅kilogram -1, p=0.017). Others were not different.

Conclusions

Dynamic IVC-guided fluid resuscitation does not affect mortality of septic patients. However, this may reduce shock duration and NE dose, compared with static CVP guidance.

A retrospective observational study evaluating the association between vasoactive-inotropic score and mortality after major abdominal surgery

The relationship between VISmax and mortality in patients undergoing major abdominal surgery remains unclear. This study aims to evaluate the association between VISmax and both short-term and long-term all-cause mortality in patients undergoing major abdominal surgery, VISmax was calculated (VISmax = dopamine dose [µg/kg/min] + dobutamine dose [µg/kg/min] + 100 × epinephrine dose [µg/kg/min] + 10 × milrinone dose [µg/kg/min] + 10,000 × vasopressin dose [units/kg/min] + 100 × norepinephrine dose [µg/kg/min]) using the maximum dosing rates of vasoactives and inotropics within the first 24 h postoperative ICU admission. The study included 512 patients first admitted to the intensive care unit (ICU) who were administered vasoactive drugs after major abdominal surgery. The data was extracted from the medical information mart in intensive care-IV database. VISmax was stratified into five categories: 0-5, > 5-15, > 15-30, > 30-45, and > 45. Compared to patients with the lowest VISmax (≤ 5), those with the high VISmax (> 45) had an increased risk of 30-day mortality (hazard ratio [HR] 3.73, 95% CI 1.16-12.02; P = 0.03) and 1-year mortality (HR 2.76, 95% CI 1.09-6.95; P = 0.03) in fully adjusted Cox models. The ROC analysis for VISmax predicting 30-day and 1-year mortality yielded AUC values of 0.69 (95% CI 0.64-0.75) and 0.67 (95% CI 0.62-0.72), respectively. In conclusion, elevated VISmax within the first postoperative 24 h after ICU admission was associated with increased risks of both short-term and long-term mortality in patients undergoing major abdominal surgery.

The impact of norepinephrine dose reporting heterogeneity on mortality prediction in septic shock patients

BACKGROUND

Norepinephrine (NE) is a cornerstone drug in the management of septic shock, with its dose being used clinically as a marker of disease severity and as mortality predictor. However, variations in NE dose reporting either as salt formulations or base molecule may lead to misinterpretation of mortality risks and hinder the process of care.

METHODS

We conducted a retrospective analysis of the MIMIC-IV database to assess the impact of NE dose reporting heterogeneity on mortality prediction in a cohort of septic shock patients. NE doses were converted from the base molecule to equivalent salt doses, and their ability to predict 28-day mortality at common severity dose cut-offs was compared.

RESULTS

4086 eligible patients with septic shock were identified, with a median age of 68 [57-78] years, an admission SOFA score of 7 [6-10], and lactate at diagnosis of 3.2 [2.4-5.1] mmol/L. Median peak NE dose at day 1 was 0.24 [0.12-0.42] μg/kg/min, with a 28-day mortality of 39.3%. The NE dose showed significant heterogeneity in mortality prediction depending on which formulation was reported, with doses reported as bitartrate and tartrate presenting 65 (95% CI 79-43)% and 67 (95% CI 80-47)% lower ORs than base molecule, respectively. This divergence in prediction widened at increasing NE doses. When using a 1 μg/kg/min threshold, predicted mortality was 54 (95% CI 52-56)% and 83 (95% CI 80-87)% for tartrate formulation and base molecule, respectively.

CONCLUSIONS

Heterogeneous reporting of NE doses significantly affects mortality prediction in septic shock. Standardizing NE dose reporting as base molecule could enhance risk stratification and improve processes of care. These findings underscore the importance of consistent NE dose reporting practices in critical care settings.

A Clinical Review of Vasopressors in Emergency Medicine

BACKGROUND

Vasopressor medications raise blood pressure through vasoconstriction and are essential in reversing the hypotension seen in many critically ill patients. Previously, vasopressor administration was largely limited to continuous infusions through central venous access.

OBJECTIVES OF THE REVIEW

This review addresses the clinical use of vasopressors in various shock states, including practical considerations and innovations in vasopressor administration. The focus is on the clinical administration of vasopressors across a range of shock states, including hypovolemic, distributive, cardiogenic, and obstructive shock.

DISCUSSION

Criteria for starting vasopressors are not clearly defined, though early use may be beneficial. A number of physiologic factors affect the body's response to vasopressors, such as acidosis and adrenal insufficiency. Peripheral and push-dose administration of vasopressors are becoming more common. Distributive shock is characterized by inappropriate vasodilation and vasopressors play a crucial role in maintaining adequate blood pressure. The use of vasopressors is more controversial in hypovolemic shock, as the preferred treatment is correction of the volume deficit. Evidence for vasopressors is limited in cardiogenic shock. For obstructive shock, vasopressors can temporize a patient's blood pressure until definitive therapy can reverse the underlying cause.

CONCLUSION

Across the categories of shock states, norepinephrine has wide applicability and is a reasonable first-line agent for shock of uncertain etiology. Keeping a broad differential when hypotension is refractory to vasopressors may help to identify adjunctive treatments in physiologic states that impair vasopressor effectiveness. Peripheral administration of vasopressors is safe and facilitates early administration, which may help to improve outcomes in some shock states.

The Sublingual Microcirculation in Critically Ill Children with Septic Shock Undergoing Hemoadsorption: A Pilot Study

Background: The importance of perfusion-guided resuscitation in septic shock has recently emerged. We explored whether the use of hemoadsorption led to a potential beneficial role in microvascular alterations in this clinical setting. Methods: A pre-planned secondary analysis of a Phase-II interventional single-arm pilot study (NCT05658588) was carried out, where 17 consecutive septic shock children admitted into PICU were treated with continuous renal replacement therapy (CRRT) and CytoSorb. Thirteen patients were eligible to be investigated with sublingual microcirculation at baseline, 24, 48, 72 and 96 h from the onset of blood purification. Patients achieving a microvascular flow index (MFI) ≥ 2.5 and/or proportion of perfused vessels (PPV) exceeding 90% by 96 h were defined as responders. Results: In 10/13 (77%), there was a significant improvement in MFIs (p = 0.01) and PPVs% (p = 0.04) between baseline and 24 h from the end of treatment. Eight patients displayed a high heterogenicity index (HI > 0.5) during blood purification and among these, five showed an improvement by the end of treatment (HI < 0.5). Conclusions: In this pilot study, we have found a potential association between CytoSorb hemoadsorption and a microcirculation improvement in pediatric patients with septic shock, particularly when this observation has been associated with hemodynamic improvement.

EARLY FLUID PLUS NOREPINEPHRINE RESUSCITATION DIMINISHES KIDNEY HYPOPERFUSION AND INFLAMMATION IN SEPTIC NEWBORN PIGS

ABSTRACT

Sepsis is the most frequent risk factor for acute kidney injury (AKI) in critically ill infants. Sepsis-induced dysregulation of kidney microcirculation in newborns is unresolved. The objective of this study was to use the translational swine model to evaluate changes in kidney function during the early phase of sepsis in newborns and the impact of fluid plus norepinephrine resuscitation. Newborn pigs (3-7-day-old) were allocated randomly to three groups: 1) sham, 2) sepsis (cecal ligation and puncture) without subsequent resuscitation, and 3) sepsis with lactated Ringer plus norepinephrine resuscitation. All animals underwent standard anesthesia and mechanical ventilation. Cardiac output and glomerular filtration rate were measured noninvasively. Mean arterial pressure, total renal blood flow, cortical perfusion, medullary perfusion, and medullary tissue oxygen tension (mtPO 2 ) were determined for 12 h. Cecal ligation and puncture decreased mean arterial pressure and cardiac output by more than 50%, with a proportional increase in renal vascular resistance and a 60-80% reduction in renal blood flow, cortical perfusion, medullary perfusion, and mtPO 2 compared to sham. Cecal ligation and puncture also decreased glomerular filtration rate by ~79% and increased AKI biomarkers. Isolated foci of tubular necrosis were observed in the septic piglets. Except for mtPO 2 , changes in all these parameters were ameliorated in resuscitated piglets. Resuscitation also attenuated sepsis-induced increases in the levels of plasma C-reactive protein, proinflammatory cytokines, lactate dehydrogenase, alanine transaminase, aspartate aminotransferase, and renal NLRP3 inflammasome. These data suggest that newborn pigs subjected to cecal ligation and puncture develop hypodynamic septic AKI. Early implementation of resuscitation lessens the degree of inflammation, AKI, and liver injury.

IMPACT OF HIGH-DOSE VASOPRESSOR DURING ENDOTOXIC SHOCK ON THE CEREBRAL, LINGUAL, HEPATIC, AND RENAL MICROCIRCULATION EVALUATED BY NEAR-INFRARED SPECTROSCOPY IN SWINE

ABSTRACT

Background: High-dose vasopressors maintain blood pressure during septic shock but may adversely reduce microcirculation in vital organs. We assessed the effect of high-dose norepinephrine and vasopressin on the microcirculation of the brain, tongue, liver, and kidney during endotoxic shock using near-infrared spectroscopy (NIRS). Methods: Thirteen pigs (24.5 ± 1.8 kg) were anesthetized, and an NIRS probe was attached directly to each organ. Approximately 0.2, 0.5, 1, and 2 μg/kg/min of norepinephrine were administered in a stepwise manner, followed by 0.5, 1, 2, and 5 μg/kg/min of sodium nitroprusside in normal condition. Moreover, 1 μg/kg/h of lipopolysaccharide was administered continuously after 100 μg bolus to create endotoxic shock and after 1,000 mL of crystalloid infusion and high-dose norepinephrine (2, 5, 10, and 20 μg/kg/min) and vasopressin (0.6, 1.5, 3, and 6 U/min) were administered in a stepwise manner. The relationship between the MAP and each tissue oxygenation index (TOI) during vasopressor infusion was evaluated. Results: Three pigs died after receiving lipopolysaccharides, and 10 were analyzed. An increase of >20% from the baseline MAP induced by high-dose norepinephrine during endotoxic shock reduced the TOI in all organs except the liver. The elevation of MAP to baseline with vasopressin alone increased the kidney and liver TOIs and decreased the tongue TOI. Conclusion: Forced blood pressure elevation with high-dose norepinephrine during endotoxic shock decreased the microcirculation of vital organs, especially the kidney. Cerebral TOI may be useful for identifying the upper limit of blood pressure, at which norepinephrine impairs microcirculation.

Angiotensin ii therapy in refractory septic shock: which patient can benefit most? A narrative review

Patients with septic shock who experience refractory hypotension despite adequate fluid resuscitation and high-dose noradrenaline have high mortality rates. To improve outcomes, evidence-based guidelines recommend starting a second vasopressor, such as vasopressin, if noradrenaline doses exceed 0.5 µg/kg/min. Recently, promising results have been observed in treating refractory hypotension with angiotensin II, which has been shown to increase mean arterial pressure and has been associated with improved outcomes. This narrative review aims to provide an overview of the pathophysiology of the renin-angiotensin system and the role of endogenous angiotensin II in vasodilatory shock with a focus on how angiotensin II treatment impacts clinical outcomes and on identifying the population that may benefit most from its use.

Extracorporeal membrane oxygenation in adult patients with sepsis and septic shock: Why, how, when, and for whom

Sepsis and septic shock remain the leading causes of death in intensive care units. Some patients with sepsis fail to respond to routine treatment and rapidly progress to refractory respiratory and circulatory failure, necessitating extracorporeal membrane oxygenation (ECMO). However, the role of ECMO in adult patients with sepsis has not been fully established. According to existing studies, ECMO may be a viable salvage therapy in carefully selected adult patients with sepsis. The choice of venovenous, venoarterial, or hybrid ECMO modes is primarily determined by the patient's oxygenation and hemodynamics (distributive shock with preserved cardiac output, septic cardiomyopathy (left, right, or biventricular heart failure), or right ventricular failure caused by acute respiratory distress syndrome). Veno-venous ECMO can be used in patients with sepsis and severe acute respiratory distress syndrome when conventional mechanical ventilation fails, and early application of veno-arterial ECMO in patients with sepsis-induced refractory cardiogenic shock may be critical in improving their chances of survival. When ECMO is indicated, the choice of an appropriate mode and determination of the optimal timing of initiation and weaning are critical, particularly in an experienced ECMO center. Furthermore, some special issues, such as ECMO flow, anticoagulation, and antibiotic therapy, should be noted during the management of ECMO support.

Prophylactic Administration with Methylene Blue Improves Hemodynamic Stabilization During Obstructive Jaundice-Related Diseases' Operation: a Blinded Randomized Controlled Trial

OBJECTIVES

Patients with obstruction jaundice are at a high risk of hypotension and need high volume of fluids and a high dose of catecholamine to maintain organ perfusion during operation procedure. All these likely contribute to high perioperative morbidity and mortality. The aim of the study is to evaluate the effects of methylene blue on the hemodynamics in patients undergoing surgeries associated with obstructive jaundice.

DESIGN

A prospective, randomized, and controlled clinical study.

SETTING

The enrolled patients randomly received 2 mg/kg of methylene blue in saline or saline (50 ml) before anesthesia induction. The primary outcome was the frequency and dose of noradrenaline administration to maintain mean arterial blood pressure over 65 mmHg or > 80% of baseline, and systemic vascular resistance (SVR) over 800 dyne/s/cm5 during operation. The secondary outcomes were liver and kidney functions, and ICU stay.

PATIENTS

Seventy patients were enrolled in the study and randomly assigned to receive either methylene blue or control (n = 35/group).

RESULTS

Fewer patients received noradrenaline in the methylene blue group when compared with the control group (13/35 vs 23/35, P = 0.017), and the noradrenaline dose administrated during operation was reduced in the methylene blue group when compared with the control group (0.32 ± 0.57 mg vs 1.787 ± 3.51 mg, P = 0.018). The blood level of creatinine, glutamic oxalacetic transaminase, and glutamic-pyruvic transaminase after the operation was reduced in the methylene blue group when compared with the control group.

CONCLUSIONS

Prophylactic administration of methylene blue before operation associated with obstructive jaundice improves hemodynamic stability and short-term prognosis.

QUESTION

Methylene blue use prevented refractory hypotension during cardiac surgery, sepsis, or anaphylactic shock. It is still unknown that methylene blue on the vascular hypo-tone associated with obstructive jaundice.

FINDINGS

Prophylactic administration with methylene blue improved peri-operative hemodynamic stability, and hepatic and kidney function on the patients with obstructive jaundice.

MEANINGS

Methylene blue is a promising and recommended drug for the patients undergoing the surgeries of relief obstructive jaundice during peri-operation management.

The Direct Effects of Norepinephrine Administration on Pressure Injuries in Intensive Care Patients: A Retrospective Cohort Study

OBJECTIVE

To estimate the direct effects of norepinephrine administration on pressure injury (PI) incidence in intensive care patients.

METHODS

This is a secondary and exploratory analysis of a retrospective cohort study of intensive care patients discharged in 2017 to 2018. Observational cases only included patients who received primary PI preventive care during intensive care (N = 479). As a first-choice vasopressor drug, norepinephrine administration was approximated with days of norepinephrine. Linear path models were examined from norepinephrine administration to PI development. The identification of confounding variables and instrumental variables was grounded on directed acyclic graph theory. Direct effects were estimated with instrumental variables to overcome bias from unobserved variables. As models were re-specified with data analysis, the robustness of path identification was improved by requiring graph invariance with sample split.

RESULTS

Norepinephrine caused PI development from one stage to another after 4.0 to 6.3 days of administration in this cohort as a total effect (90% CI). The direct effect was estimated to advance the stage of PI at a rate of 0.140 per day of norepinephrine administered (standard error, 0.029; P < .001). The direct effect accounted for about 70% of the total effect on PI development.

CONCLUSIONS

Estimations with instrumental variables and structural equation modeling showed that norepinephrine administration directly and substantially affected hospital-acquired PI incidence in intensive care patients in this cohort.

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.

Association between the timing of ICU admission and mortality in patients with hospital-onset sepsis: a nationwide prospective cohort study

BACKGROUND

Based on sparse evidence, the current Surviving Sepsis Campaign guideline suggests that critically ill patients with sepsis be admitted to the intensive care unit (ICU) within 6 h. However, limited ICU bed availability often makes immediate transfer difficult, and it is unclear whether all patients will benefit from early admission to the ICU. Therefore, the purpose of this study was to determine the association between the timing of ICU admission and mortality in patients with hospital-onset sepsis.

METHODS

This nationwide prospective cohort study analyzed patients with hospital-onset sepsis admitted to the ICUs of 19 tertiary hospitals between September 2019 and December 2020. ICU admission was classified as either early (within 6 h) or delayed (beyond 6 h). The primary outcome of in-hospital mortality was compared using logistic regression adjusted for key prognostic factors in the unmatched and 1:1 propensity-score-matched cohorts. Subgroup and interaction analyses assessed whether in-hospital mortality varied according to baseline characteristics.

RESULTS

A total of 470 and 286 patients were included in the early and delayed admission groups, respectively. Early admission to the ICU did not significantly result in lower in-hospital mortality in both the unmatched (adjusted odds ratio [aOR], 1.35; 95% confidence interval [CI], 0.99-1.85) and matched cohorts (aOR, 1.38; 95% CI, 0.94-2.02). Subgroup analyses showed that patients with increasing lactate levels (aOR, 2.10; 95% CI, 1.37-3.23; P for interaction = 0.003), septic shock (aOR, 2.06; 95% CI, 1.31-3.22; P for interaction = 0.019), and those who needed mechanical ventilation (aOR, 1.92; 95% CI, 1.24-2.96; P for interaction = 0.027) or vasopressor support (aOR, 1.69; 95% CI, 1.17-2.44; P for interaction = 0.042) on the day of ICU admission had a higher risk of mortality with delayed admission.

CONCLUSIONS

Among patients with hospital-onset sepsis, in-hospital mortality did not differ significantly between those with early and delayed ICU admission. However, as early intensive care may benefit those with increasing lactate levels, septic shock, and those who require vasopressors or ventilatory support, admission to the ICU within 6 h should be considered for these subsets of patients.

Early adjunctive methylene blue in patients with septic shock: a randomized controlled trial

PURPOSE

Methylene blue (MB) has been tested as a rescue therapy for patients with refractory septic shock. However, there is a lack of evidence on MB as an adjuvant therapy, its' optimal timing, dosing and safety profile. We aimed to assess whether early adjunctive MB can reduce time to vasopressor discontinuation in patients with septic shock.

METHODS

In this single-center randomized controlled trial, we assigned patients with septic shock according to Sepsis-3 criteria to MB or placebo. Primary outcome was time to vasopressor discontinuation at 28 days. Secondary outcomes included vasopressor-free days at 28 days, days on mechanical ventilator, length of stay in ICU and hospital, and mortality at 28 days.

RESULTS

Among 91 randomized patients, forty-five were assigned to MB and 46 to placebo. The MB group had a shorter time to vasopressor discontinuation (69 h [IQR 59-83] vs 94 h [IQR 74-141]; p < 0.001), one more day of vasopressor-free days at day 28 (p = 0.008), a shorter ICU length of stay by 1.5 days (p = 0.039) and shorter hospital length of stay by 2.7 days (p = 0.027) compared to patients in the control group. Days on mechanical ventilator and mortality were similar. There were no serious adverse effects related to MB administration.

CONCLUSION

In patients with septic shock, MB initiated within 24 h reduced time to vasopressor discontinuation and increased vasopressor-free days at 28 days. It also reduced length of stay in ICU and hospital without adverse effects. Our study supports further research regarding MB in larger randomized clinical trials. Trial registration ClinicalTrials.gov registration number NCT04446871 , June 25, 2020, retrospectively registered.

Not all Shock States Are Created Equal: A Review of the Diagnosis and Management of Septic, Hypovolemic, Cardiogenic, Obstructive, and Distributive Shock

Shock in the critically ill patient is common and associated with poor outcomes. Categories include distributive, hypovolemic, obstructive, and cardiogenic, of which distributive (and usually septic distributive) shock is by far the most common. Clinical history, physical examination, and hemodynamic assessments & monitoring help differentiate these states. Specific management necessitates interventions to correct the triggering etiology as well as ongoing resuscitation to maintain physiologic milieu. One shock state may convert to another and may have an undifferentiated presentation; therefore, continual re-assessment is essential. This review provides guidance for intensivists for management of all shock states based on available scientific evidence.

[Fluid and vasopressor therapy in sepsis]

Sepsis is one of the most common and lethal conditions in intensive care medicine. Besides adequate treatment of the infection, timely hemodynamic management is essential to treat tissue hypoperfusion due to sepsis. Adequate fluid resuscitation plays a central role, and this should be carried out with dynamic monitoring of the hemodynamic response. However, a positive fluid balance is associated with poor outcome. Vasopressor therapy is required in case of inadequate response to fluid resuscitation, with norepinephrine considered the first choice. With increasing norepinephrine dose, addition of hydrocortisone or vasopressin may contribute to maintaining the hemodynamic state, although the prognostic advantage of these drugs has not been demonstrated. While dobutamine may be considered in patients with septic cardiomyopathy, the evidence for inotropic therapy in sepsis is limited.

How We Escalate Vasopressor and Corticosteroid Therapy in Patients With Septic Shock

Septic shock is defined by the need for vasopressor agents to correct hypotension and lactic acidosis resulting from infection, with 30%-40% case fatality rates. The care of patients with worsening septic shock involves multiple treatment decisions involving vasopressor choices and adjunctive treatments. In this edition of "How I Do It", we provide a case-based discussion of common clinical decisions regarding choice of first-line vasopressor, BP targets, route of vasopressor delivery, use of secondary vasopressors, and adjunctive medications. We also consider diagnostic approaches, treatment, and monitoring strategies for the patient with worsening shock, as well as approaches to difficult weaning of vasopressors.

Dexmedetomidine only regimen for long-term sedation is associated with reduced vasopressor requirements in septic shock patients: A retrospective cohort study from MIMIC-IV database

Background

Previous studies have shown that dexmedetomidine (DEX) may be associated with reduced vasopressor requirements in septic shock patients, however, long-term DEX-only sedation in reducing vasopressor requirements is still controversial.

Methods

A retrospective study was conducted among patients with septic shock on mechanical ventilation using the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. The primary outcome was the ratio of norepinephrine equivalent dose to mean arterial pressure (NEq/MAP) in the first 72 h after DEX or other sedatives for sedation. The secondary outcomes were key organ function parameters, 28-day mortality, and 90-day mortality. Univariate, propensity score matching (PSM), and generalized linear mixed model (GLMM) analyses were performed.

Results

DEX was associated with decreased NEq/MAP in the first 72 h (difference = 0.05, 95% CI = -0.02-0.08, p = 0.002) after adjusting for confounders in the GLMM analysis. The DEX group was also associated with a lower heart rate, cardiac output (CO), lactate level, aspartate transaminase (AST) level, and higher PaO2/FiO2 ratio (p < 0.0125). Moreover, DEX only sedation was associated with reduced 90-day mortality (OR = 0.60, 95% CI = 0.37-0.94, p = 0.030).

Conclusion

DEX may be associated with decreased vasopressor requirements, improved AST and PaO2/FiO2 levels, and reduced 90-day mortality in patients with septic shock, which warrants further study.

Refractory septic shock and alternative wordings: A systematic review of literature

BACKGROUND

We reviewed the different studies using the terms "refractory septic shock" and/or "catecholamine resistance" and/or "high dose norepinephrine" so as to highlight the heterogeneity of the definitions used by authors addressing such concepts.

METHOD

A systematic review was conducted assessing the papers reporting data on refractory septic shock. We used keywords as exact phrases and subject headings according to database syntax.

RESULTS

Of 276 papers initially reviewed, we included 8 studies - 3 randomized controlled trials, 3 prospective studies and 2 retrospective studies, representing a total of 562 patients with septic shock. Catecholamine resistance was generally defined as "a decreased vascular responsiveness to catecholamine independently of the administered norepinephrine dose". Refractory septic shock was broadly defined as "a clinical condition characterized by persistent hyperdynamic shock even though adequate fluid resuscitation (individualized doses) and high doses of norepinephrine (≥ 1 μg/kg/min)". Reported "high doses" of norepinephrine were often ≥1 μg/kg/min. However, wide variability was found throughout the literature on the use of these terms.

DISCUSSION

Marked inconsistencies were identified in the usage of the terms for refractory septic shock. There is a pressing need to determine consensus definitions so as to establish a common language in the medical literature and to harmonize future studies.

Multimodal strategy to counteract vasodilation in septic shock

Early initiation of a multimodal treatment strategy in the management of vasopressors during septic shock has been advocated to reduce delays in restoring adequate organ perfusion and to mitigate side effects associated with the administration of high-dose catecholamines. We provide a review that summarises the pathophysiology of vasodilation, the physiologic response to the vascular response, and the different drugs used in this situation, focusing on the need to combine early different vasopressors. Fluid loading being insufficient for counteracting vasoplegia, norepinephrine is usually the first-line vasopressor used to restore hemodynamics. Norepinephrine sparing is discussed in further detail through the concomitant use of adrenergic, vasopressinergic, and renin-angiotensin systems and the optimisation of endothelial reactivity with methylene blue. A blueprint for the construction of new studies is outlined to address the question of vasopressor selection and timing in septic shock.

Arterial site selection for measurement of mean arterial pressure in septic shock patients on high-dose norepinephrine

Background

The guidelines of the Surviving Sepsis Campaign suggest using invasive blood pressure (IBP) measurement in septic shock patients, without specifying for a preferred arterial site for accuracy in relation to the severity of septic shock. The objective of this study was to determine the mean arterial pressure (MAP) gradient between the femoral and radial artery sites in septic shock patients.

Method

This prospective study was carried out at a 20-bed ICU in a university hospital. Simultaneous MAP measurements at femoral and radial arterial sites were obtained in septic shock patients receiving norepinephrine (≥0.1 μg/kg/min), with a pre-planned subgroup analysis for those receiving a high dose of norepinephrine (≥0.3 μg/kg/min).

Results

The median norepinephrine dose across all 80 patients studied, including 59 patients on a high dose, was 0.4 (0.28-0.7) μg/kg/min. Overall, simultaneous measurement of MAP (mmHg) at the femoral and radial arterial sites produced mean (95% CI) MAP values of 81 (79-83) and 78 (76-80), respectively, with a mean difference of 3.3 (2.67-3.93), p < 0.001. In Bland-Altman analysis of MAP measurements, the detected effect sizes were 1.14 and 1.04 for the overall and high-dose cohorts, respectively, which indicates a significant difference between the measurements taken at each of the two arterial sites. The Pearson correlation coefficient indicated a weak but statistically significant correlation between MAP gradient and norepinephrine dose among patients receiving a high dose of norepinephrine (r = 0.289; p = 0.026; 95% CI 0.036-0.508).

Conclusion

In septic shock patients, MAP readings were higher at the femoral site than at the radial site, particularly in those receiving a high dose of norepinephrine.

Clinical trial registration

[ClinicalTrials.gov], identifier [NCT03475667].

Dexmedetomidine to reduce vasopressor resistance in refractory septic shock: Protocol for a double-blind randomized controlled pilot trial (ADRESS Pilot study)

Introduction

Refractory septic shock (RSS) is characterized by high vasopressor requirements, as a consequence of vasopressor resistance, which may be caused or enhanced by sympathetic hyperactivation. Experimental models and clinical trials show a reduction in vasopressor requirements and improved microcirculation compared to conventional sedation. Dexmedetomidine did not reduce mortality in clinical trials, but few septic shock patients were enrolled. This pilot trial aims to evaluate vasopressor re-sensitization with dexmedetomidine and assess the effect size, in order to design a larger trial.

Methods

This is an investigator-initiated, multicenter, randomized, double-blind, placebo-controlled trial, comparing dexmedetomidine versus placebo in RSS patients with norepinephrine dose ≥0.5μg/kg/min. The primary outcome is blood pressure response to phenylephrine challenge, 6 hours after completion of a first challenge, after study treatment initiation. Secondary outcomes include feasibility and safety outcomes (bradycardia), mortality, vasopressor requirements, heart rate variability, plasma and urine catecholamines levels. The sample size is estimated at 32 patients to show a 20% improvement in blood pressure response to phenylephrine. Randomization (1:1) will be stratified by center, sedation type and presence of liver cirrhosis. Blood pressure and ECG will be continuously recorded for the first 24 h, enabling high-quality data collection for the primary and secondary endpoints. The study was approved by the ethics committee “Sud-Est VI” (2019-000726-22) and patients will be included after informed consent.

Discussion

The present study will be the first randomized trial to specifically address the hemodynamic effects of dexmedetomidine in patients with septic shock. We implement a high-quality process for data acquisition and recording in the first 24 h, ensuring maximal quality for the evaluation of both efficacy and safety outcomes, as well as transparency of results. The results of the study will be used to elaborate a full-scale randomized controlled trial with mortality as primary outcome in RSS patients.

Trial registration

Registered with ClinicalTrials.gov (NCT03953677). Registered 16 May 2019, https://clinicaltrials.gov/ct2/show/NCT03953677.

Blood purification therapy in patients with severe COVID-19 requiring veno-venous ECMO therapy: A retrospective study

OBJECTIVE

Patients with severe manifestations of COVID-19 might exhibit characteristics of a sepsis-like syndrome that can progress to multiple organ failure and ultimately death. Underlying mechanism have been explored and suggest a profound dysregulation of the immune system associated with hyperinflammation, hemodynamic instability and respiratory failure. Besides standard intensive care treatment, approaches modulating the dysregulated immune response, such as CytoSorb hemoadsorption, have been used. However, data of ECMO-dependent patients in comparison to a control cohort remain scarce.

METHODS

Included were 26 critically ill COVID-19 patients requiring high-flow veno-venous extracorporeal membrane oxygenation (high-flow VV ECMO) therapy due to severe acute respiratory distress syndrome (ARDS), of whom 16 were additionally treated with an extracorporeal hemoadsorption device, and compared to a control group of 10 patients. Assessed were levels of inflammatory markers, vasopressor requirements, oxygenation parameters, as well as clinically relevant outcome variables. Data were prospectively recorded and retrospectively analyzed.

RESULTS

Treatment with the applied multimodal therapy approach resulted in a stabilization in hemodynamics, a control of the hyperinflammatory response as evidenced by a significant reduction in inflammatory mediators, as well as a marked improvement in lung function. No device related adverse events were observed while treatment appeared safe and feasible.

CONCLUSION

Treatment of a critically ill COVID-19 ARDS patients with combined VV ECMO support and hemoadsorption therapy led to a rapid and sustained hemodynamic stabilization, a control of the uncontrolled inflammatory response and an improvement in oxygenation. Given these signals pointing toward a patient-oriented benefit of extracorporeal hemoadsorption therapy in those patients, future controlled, randomized studies should focus on the investigation of the appropriate timing and dosing of this promising treatment modality.

Selepressin in Septic Shock

ABSTRACT

Sepsis and septic shock usually show a high mortality rate and frequently need of intensive care unit admissions. After fluid resuscitation, norepinephrine (NE) is the first-choice vasopressor in septic shock patients. However, high-NE doses are associated with increased rates of adverse effects and mortality. In this perspective, many authors have proposed the administration of non-adrenergic vasopressors (NAV). Selepressin is a selective vasopressin type 1A (V1A) receptor agonist and may be a valid option in this field, because it can decrease NE requirements and also limit the deleterious effects induced by high doses of catecholamines. Only few clinical data actually support selepressin administration in this setting. Here, we review the current literature on this topic analyzing some pathophysiological aspects, the rationale about the use of NAV, the possible use of selepressin differentiating animal, and human studies. Various issues remain unresolved and future trials should be focused on early interventions based on a multimodal activation of the vasopressive pathways using both alpha and V1A receptors pathways.

Timing of vasoactive agents and corticosteroid initiation in septic shock

Septic shock remains a health care concern associated with significant morbidity and mortality. The Surviving Sepsis Campaign Guidelines for Management of Sepsis and Septic Shock recommend early fluid resuscitation and antimicrobials. Beyond initial management, the guidelines do not provide clear recommendations on appropriate time to initiate vasoactive therapies and corticosteroids in patients who develop shock. This review summarizes the literature regarding time of initiation of these interventions. Clinical data regarding time of initiation of these therapies in relation to shock onset, sequence of treatments with regard to each other, and clinical markers evaluated to guide initiation are summarized. Early-high vasopressor initiation within first 6 h of shock onset is associated with lower mortality. Following norepinephrine initiation, the exact dose and timing of escalation to adjunctive vasopressor agents are not well elucidated in the literature. However, recent data indicate that timing may be an important factor in initiating vasopressors and adjunctive therapies, such as corticosteroids. Norepinephrine-equivalent dose and lactate concentration can aid in determining when to initiate vasopressin and angiotensin II in patients with septic shock. Future guidelines with clear recommendations on the time of initiation of septic shock therapies are warranted.

Effects of methylene blue on microcirculatory alterations following cardiac surgery: A prospective cohort study

BACKGROUND

Methylene blue is used as rescue therapy to treat catecholamine-refractory vasoplegic syndrome after cardiac surgery. However, its microcirculatory effects remain poorly documented.

OBJECTIVE

We aimed to study microcirculatory abnormalities in refractory vasoplegic syndrome following cardiac surgery with cardiopulmonary bypass and assess the effects of methylene blue.

DESIGN

A prospective open-label cohort study.

SETTING

20-Bed ICU of a tertiary care hospital.

PATIENTS

25 Adult patients receiving 1.5 mg kg-1 of methylene blue intravenously for refractory vasoplegic syndrome (defined as norepinephrine requirement more than 0.5 μg kg-1 min-1) to maintain mean arterial pressure (MAP) more than 65 mmHg and cardiac index (CI) more than 2.0 l min-1 m-2.

MAIN OUTCOME MEASURES

Complete haemodynamic set of measurements at baseline and 1 h after the administration of methylene blue. Sublingual microcirculation was investigated by sidestream dark field imaging to obtain microvascular flow index (MFI), total vessel density, perfused vessel density and heterogeneity index. Microvascular reactivity was assessed by peripheral near-infrared (IR) spectroscopy combined with a vascular occlusion test. We also performed a standardised measurement of capillary refill time.

RESULTS

Despite normalised CI (2.6 [2.0 to 3.8] l min-1 m-2) and MAP (66 [55 to 76] mmHg), patients with refractory vasoplegic syndrome showed severe microcirculatory alterations (MFI < 2.6). After methylene blue infusion, MFI significantly increased from 2.0 [0.1 to 2.5] to 2.2 [0.2 to 2.8] (P = 0.008), as did total vessel density from 13.5 [8.3 to 18.5] to 14.9 [10.1 to 14.7] mm mm-2 (P = 0.02) and perfused vessel density density from 7.4 [0.1 to 11.5] to 9.1 [0 to 20.1] mm mm-2 (P = 0.02), but with wide individual variation. Microvascular reactivity assessed by tissue oxygen resaturation speed also increased from 0.5 [0.1 to 1.8] to 0.7 [0.1 to 2.7]% s-1 (P = 0.002). Capillary refill time remained unchanged throughout the study.

CONCLUSION

In refractory vasoplegic syndrome following cardiac surgery, we found microcirculatory alterations despite normalised CI and MAP. The administration of methylene blue could improve microvascular perfusion and reactivity, and partially restore the loss of haemodynamic coherence.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT04250389.

Vasopressor Choice and Timing in Vasodilatory Shock

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2022. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2022 . Further information about the Annual Update in Intensive Care and Emergency Medicine is available from https://link.springer.com/bookseries/8901 .

Achieving Functional Outcomes after Surgical Management of Catastrophic Vasopressor-induced Limb Ischemia

Vasopressor-induced limb ischemia is an unfortunate complication that can occur in patients treated for septic shock. Current literature lacks surgical treatment recommendations for this condition, besides amputation. We describe various reconstructive surgeries and functional outcomes in patients treated surgically for vasopressor-induced limb ischemia.

Methods

We retrospectively reviewed patients who were treated for septic shock and developed vasopressor-induced limb ischemia at our tertiary referral academic medical center. We reviewed presentation, treatment, surgical outcomes, and long-term functional outcomes.

Results

We present three previously healthy patients who developed gangrene of multiple limbs following the use of vasopressors to treat septic shock. Each patient underwent amputations or limb salvage procedures.

Conclusions

Limb ischemia is a devastating complication that can occur after prolonged vasopressor use. The decision to proceed with limb salvage versus amputation of ischemic extremities should be tailored to the individual patient. The main objective should be for the patient to obtain optimal function and quality of life, regardless of the type of surgery.

Acute Liver Injury in Patients Hospitalized with COVID-19

INTRODUCTION

The prevalence and significance of acute liver injury in patients with COVID-19 are poorly characterized.

METHODS

Patients with confirmed COVID-19 who were hospitalized in geographically diverse medical centers in North America were included. Demographics, symptoms, laboratory data results, and outcomes were recorded. Linear and logistic regression identified factors associated with liver injury, in-hospital mortality, and length of stay (LOS).

RESULTS

Among 1555 patients in the cohort, most (74%) had an elevated alanine aminotransferase (ALT) during hospitalization, which was very severe (> 20 × upper limit of normal [ULN]) in 3%. Severe acute liver injury (ALI) was uncommon, occurring in 0.1% on admission and 2% during hospitalization. No patient developed acute liver failure (ALF). Higher ALT was associated with leukocytosis (per mL³) (β 10.0, 95% confidence interval (CI) 6.7-12.6, p < 0.001) and vasopressors use (β 80.2, 95%CI 21.5-138.8, p = 0.007). In-hospital mortality was associated with ALT > 20 × ULN (unadjusted OR 6.0, 95%CI 3.1-11.5, p < 0.001), ALP > 3 × ULN (unadjusted OR 4.4, 95%CI 2.5-7.7, p < 0.001), and severe ALI (unadjusted OR 6.8, 95%CI 3.0-15.3, p < 0.001) but lost significance after adjusting for covariates related to severe COVID-19 and hemodynamic instability. Elevated ALP and ALT were associated with longer LOS, admission to intensive care, mechanical ventilation, vasopressor use, and extracorporeal membrane oxygenation use (p < 0.001).

CONCLUSIONS

Transaminase elevation is common in hospitalized patients with COVID-19. Severe ALI is rare, and ALF may not be a complication of COVID-19. Extreme elevations in liver enzymes appear to be associated with mortality and longer LOS due to more severe systemic disease rather than SARS-CoV-2-related hepatitis.

Right Ventricular Outflow Tract Obstruction in the Intensive Care Unit: A Case Report of 2 Patients

Right ventricular outflow tract obstruction (RVOTO) is a rare cause of hemodynamic instability in the intensive care unit (ICU) after cardiac surgery. We report the first cases of RVOTO diagnosed in the ICU using continuous right ventricular pressure waveform monitoring. Our 2 cases reflect both mechanical and dynamic causes of obstruction, each of which require different approaches to treatment. Inotrope use can exacerbate RVOTO caused by dynamic etiology, whereas surgery is usually the treatment of choice for mechanical obstructions. Inability to recognize RVOTO or the correct etiology can lead to hemodynamic compromise and poor outcomes.

Outcomes and Risk Factors of Critically Ill Patients with Hematological Malignancy. Prospective Single-Centre Observational Study

Background and Objectives: Oncohematological patients have a high risk of mortality when they need treatment in an intensive care unit (ICU). The aim of our study is to analyze the outcomes of oncohemathological patients admitted to the ICU and their risk factors. Materials and Methods: A prospective single-center observational study was performed with 114 patients from July 2017 to December 2019. Inclusion criteria were transfer to an ICU, hematological malignancy, age >18 years, a central line or arterial line inserted or planned to be inserted, and a signed informed consent form. Univariate and multivariable logistic regression models were used to evaluate the potential risk factors for ICU mortality. Results: ICU mortality was 44.74%. Invasive mechanical ventilation in ICU was used for 55.26% of the patients, and vasoactive drugs were used for 77.19% of patients. Factors independently associated with it were qSOFA score ≥2, increase of SOFA score over the first 48 h, mechanical ventilation on the first day in ICU, need for colistin therapy, lower arterial pH on arrival to ICU. Cut-off value of the noradrenaline dose associated with ICU mortality was 0.21 μg/kg/min with a ROC of 0.9686 (95% CI 0.93-1.00, p < 0.0001). Conclusions: Mortality of oncohematological patients in the ICU is high and it is associated with progression of organ dysfunction over the first 48 h in ICU, invasive mechanical ventilation and need for relatively low dose of noradrenaline. Despite our findings, we do not recommend making decisions regarding treatment limitations for patients who have reached cut-off dose of noradrenaline.

Non-invasive detection of a femoral-to-radial arterial pressure gradient in intensive care patients with vasoactive agents

BACKGROUND

In patient requiring vasopressors, the radial artery pressure may underestimate the true central aortic pressure leading to unnecessary interventions. When using a femoral and a radial arterial line, this femoral-to-radial arterial pressure gradient (FR-APG) can be detected. Our main objective was to assess the accuracy of non-invasive blood pressure (NIBP) measures; specifically, measuring the gradient between the NIBP obtained at the brachial artery and the radial artery pressure and calculating the non-invasive brachial-to-radial arterial pressure gradient (NIBR-APG) to detect an FR-APG. The secondary objective was to assess the prevalence of the FR-APG in a targeted sample of critically ill patients.

METHODS

Adult patients in an intensive care unit requiring vasopressors and instrumented with a femoral and a radial artery line were selected. We recorded invasive radial and femoral arterial pressure, and brachial NIBP. Measurements were repeated each hour for 2 h. A significant FR-APG (our reference standard) was defined by either a mean arterial pressure (MAP) difference of more than 10 mmHg or a systolic arterial pressure (SAP) difference of more than 25 mmHg. The diagnostic accuracy of the NIBR-APG (our index test) to detect a significant FR-APG was estimated and the prevalence of an FR-APG was measured and correlated with the NIBR-APG.

RESULTS

Eighty-one patients aged 68 [IQR 58-75] years and an SAPS2 score of 35 (SD 7) were included from which 228 measurements were obtained. A significant FR-APG occurred in 15 patients with a prevalence of 18.5% [95%CI 10.8-28.7%]. Diabetes was significantly associated with a significant FR-APG. The use of a 11 mmHg difference in MAP between the NIBP at the brachial artery and the MAP of the radial artery led to a specificity of 92% [67; 100], a sensitivity of 100% [95%CI 83; 100] and an AUC ROC of 0.93 [95%CI 0.81-0.99] to detect a significant FR-APG. SAP and MAP FR-APG correlated with SAP (r2 = 0.36; p < 0.001) and MAP (r2 = 0.34; p < 0.001) NIBR-APG.

CONCLUSION

NIBR-APG assessment can be used to detect a significant FR-APG which occur in one in every five critically ill patients requiring vasoactive agents.

Associations between peripheral perfusion disorders, mean arterial pressure and dose of norepinephrine administrated in the early phase of septic shock

The aim of the study was to explore the correlations between peripheral perfusion, mean arterial pressure and the dose-rate of norepinephrine (NE) infused for the treatment of septic shock. The study is retrospective analysis of data acquired prospectively on 57 patients during the first 24 hours after the occurrence of the shock. Clinical and haemodynamic characteristics, skin perfusion parameters (capillary refill time [CRT], mottling score and temperature gradients) and the dose rate of NE infusion were collected. Negative correlations between mean arterial pressure (MAP) and temperature gradients (core-to-toe: P = .03, core-to-index: P = .04) were found and abnormal CRT was associated with lower MAP (P = .02). The dose rate of NE was negatively correlated with temperature gradients (core-to-toe: P = .02, core-to-index: P = .01, forearm-to-index: P = .008) in the overall population. In patients receiving NE for at least 12 hours, the NE dose rate positively was correlated with the mottling score (P = .006), temperature gradients (core-to-toe: P = .04, forearm-to-index: P = .02, core-to-index: P = .005) and CRT (P = .001). The dose of NE administrated was associated with 14-days mortality (odds ration [OR] = 1.21 [1.06-1.38], P = .006) and with 28-days mortality (OR = 1.17 [1.01-1.36], P = 0.04). In conclusion, the study described the presence of correlations between peripheral perfusion and MAP and between peripheral perfusion and the dose rate of NE infusion.

The Potential Role of Extracorporeal Cytokine Removal in Hemodynamic Stabilization in Hyperinflammatory Shock

Hemodynamic instability due to dysregulated host response is a life-threatening condition requiring vasopressors and vital organ support. Hemoadsorption with Cytosorb has proven to be effective in reducing cytokines and possibly in attenuating the devastating effects of the cytokine storm originating from the immune over-response to the initial insult. We reviewed the PubMed database to assess evidence of the impact of Cytosorb on norepinephrine needs in the critically ill. We further analyzed those studies including data on control cohorts in a comparative pooled analysis, defining a treatment effect as the standardized mean differences in relative reductions in vasopressor dosage at 24 h. The literature search returned 33 eligible studies. We found evidence of a significant reduction in norepinephrine requirement after treatment: median before, 0.55 (IQR: 0.39-0.90); after, 0.09 (0.00-0.25) μg/kg/min, p < 0.001. The pooled effect size at 24 h was large, though characterized by high heterogeneity. In light of the importance of a quick resolution of hemodynamic instability in the critically ill, further research is encouraged to enrich knowledge on the potentials of the therapy.

Vasoactive agents in acute mesenteric ischaemia in critical care. A systematic review

Background: Acute mesenteric ischaemia (AMI) is a surgical emergency which has an associated high mortality.  The mainstay of active treatment includes early surgical intervention, with resection of non-viable bowel, and revascularisation of the ischaemic bowel where possible. Due to the physiological insult of AMI however, perioperative care often involves critical care and the use of vasoactive agents to optimise end organ perfusion. A number of these vasoactive agents are currently available with varied mechanism of action and effects on splanchnic blood flow. However, specific guidance on which is the optimal vasoactive drug to use in these settings is limited. This systematic review aimed to evaluate the current evidence comparing vasoactive drugs in AMI. Methods: A systematic search of Ovid Medline, Ovid Embase, Cochrane CENTRAL and the Cochrane Database of Systematic Review was performed on the 5th of November 2020 to identify randomised clinical trials comparing different vasoactive agents in AMI on outcomes including mortality. The search was performed through the Royal College of Surgeons of England (RCSEng) search support library. Results were analysed using the Rayyan platform, and independently screened by four investigators. Results: 614 distinct papers were identified. After screening, there were no randomised clinical trials meeting the inclusion criteria. Conclusions: This review identifies a gap in literature, and therefore recommends an investigation into current practice and clinician preference in relation to vasoactive agents in AMI. Multicentre randomised controlled trials comparing these medications on clinical outcomes will therefore be required to address this question.

Vasoactive agents in acute mesenteric ischaemia in critical care. A systematic review

Background: Acute mesenteric ischaemia (AMI) is a surgical emergency which has an associated high mortality.  The mainstay of active treatment includes early surgical intervention, with resection of non-viable bowel, and revascularisation of the ischaemic bowel where possible. Due to the physiological insult of AMI however, perioperative care often involves critical care and the use of vasoactive agents to optimise end organ perfusion. A number of these vasoactive agents are currently available with varied mechanism of action and effects on splanchnic blood flow. However, specific guidance on which is the optimal vasoactive drug to use in these settings is limited. This systematic review aimed to evaluate the current evidence comparing vasoactive drugs in AMI. Methods: A systematic search of Ovid Medline, Ovid Embase, Cochrane CENTRAL and the Cochrane Database of Systematic Review was performed on the 5th of November 2020 to identify randomised clinical trials comparing different vasoactive agents in AMI on outcomes including mortality. The search was performed through the Royal College of Surgeons of England (RCSEng) search support library. Results were analysed using the Rayyan platform, and independently screened by four investigators. Results: 614 distinct papers were identified. After screening, there were no randomised clinical trials meeting the inclusion criteria. Conclusions: This review identifies a gap in literature, and therefore recommends an investigation into current practice and clinician preference in relation to vasoactive agents in AMI. Multicentre randomised controlled trials comparing these medications on clinical outcomes will therefore be required to address this question.

Norepinephrine-Induced Peripheral Ischemia Leading to Gangrene: A Case Series

ABSTRACT

Norepinephrine is used in the acute care setting to establish and maintain hemodynamic stability in patients with hypotension. Although it is often a lifesaving medication, norepinephrine may lead to profound vascular insufficiency in the extremities, resulting in dry gangrene and skin necrosis. The purpose of this article is to present a case series of skin complications related to treatment with norepinephrine and review the pathophysiology behind these complications. The authors also explore risk stratification as it relates to history and clinical presentation with subsequent focus on contingencies to mitigate the adverse effects of vasoconstriction on peripheral tissues.

Acute kidney injury after lung transplantation: a narrative review

Acute kidney injury (AKI) is a commonly recognized complication after lung transplantation (LT) and is related to increased mortality and morbidity. With the improvement of survival after LT and the increasing number of lung transplant recipients, the detrimental impact of current management on renal function has become increasingly apparent. Multifarious risk factors in the perioperative setting contribute to the development of AKI, including the preoperative status and complications of the recipient, complex perioperative problems especially hemodynamic fluctuation, and exposure to nephrotoxic agents, mainly calcineurin inhibitors (CNIs) and antimicrobial drugs. Identification and minimization of the effects of these risk factors can relieve AKI severity and incidence in high-risk patients. Close monitoring of urine output and serum creatinine (sCr) levels and of specific biomarkers may promote early recognition of AKI and rapid nephrology intervention to improve outcomes. This review summarizes advances in the epidemiology, diagnostic criteria, biological markers of AKI, and further recommends appropriate treatment strategies for the long-term management of AKI related manifestations in lung transplant recipients. Future work will need to focus on developing more accurate measures of renal function and identifying patients before the occurrence of early renal damage. Combining renal protection strategies with the use of new biomarkers to develop early kidney risk identification and protection protocols is a promising idea that requires further investigation.

A time-sensitive analysis of the prognostic utility of vasopressor dose in septic shock

It is unclear whether the association between vasopressor dose and mortality is affected by duration of administration. We examined whether prognostication in septic shock is feasible through the use of daily median vasopressor doses. We undertook a single-centre retrospective cohort study. We included patients with a diagnosis of septic shock admitted to the intensive care unit at Queen Elizabeth Hospital, Birmingham, UK, between April 2016 and July 2019. The primary outcome measure was 90-day mortality. We defined vasopressor dose as the median norepinephrine equivalent dose (equivalent infusion rates of all vasopressors and inotropes) recorded for each day, for the first four days of septic shock. We divided patients into groups by vasopressor dose quintiles and calculated their 90-day mortality rate. We examined area under the receiver operator characteristic curves for prognostic ability. In total, 844 patients were admitted with septic shock and had a 90-day mortality of 43% (n = 358). Over the first four days, median vasopressor dose decreased in 93% of survivors and increased in 56% of non-survivors. The mortality rate associated with a given vasopressor dose quintile increased on sequential days of septic shock. The area under the receiver operator characteristic curves of daily median vasopressor dose against mortality increased from day 1 to day 4 (0.67 vs. 0.86, p < 0.0001). By day 4, a median daily vasopressor dose > 0.05 μg.kg^-1 .min^-1 had an 80% sensitivity and specificity for mortality. The prognostic utility of vasopressor dose improved considerably with shock duration. Prolonged administration of small vasopressor doses was associated with a high attributable mortality.

Management of vasopressor induced ischemia

Purpose

We evaluated a cohort of patients who developed vasopressor-induced limb ischemia and the management options to prevent progression or minimize morbidity of digital necrosis.

Methods

We reviewed all current literature on pressor-induced limb ischemia and report options for the management of patients requiring vasopressors who developed limb ischemia. We then retrospectively reviewed presentation, treatment, and short-term outcomes for patients at our tertiary referral academic medical center that developed this complication. Finally, we recommend guidelines for the tiered management of these complex patients.

Results

Thirty-six patients were included. Twenty-six patients (72%) required resuscitation with more than one vasopressor. Vasopressors were initiated for septic-shock (52.7%), cardiogenic-shock (16.7%), hypovolemic-shock (13.9%), acute transplant rejection (13.9%), and neurogenic-shock (2.8%). According to the tiered management recommendations, patients were managed with phase 1 care (19%), phase 2 care (8.3%), phase 3 care (50%) or phase 4 care (5.6%). The patient expired in the acute setting in 13.9% of cases.

Conclusion

Life-saving vasopressors risk digital ischemia and necrosis. Early recognition, reporting, and treatment of this complication are important in minimizing morbidity. Using a tiered approach helps organize the healthcare team's management of this iatrogenic complication while respecting the treatment paradigm of "life over limb," and may be safely performed with acceptable outcomes.