Resuscitating the macro- vs. microcirculation in septic shock.

PURPOSE OF REVIEW: This review summarizes current literature about the relationships between macro and microcirculation and their practical clinical implications in children with septic shock. RECENT FINDINGS: Current evidence from experimental and clinical observational studies in children and adults with septic shock reveals that the response to treatment and resuscitation is widely variable. Furthermore, there is a loss of hemodynamic coherence, as resuscitation-induced improvement in macrocirculation (systemic hemodynamic parameters) does not necessarily result in a parallel improvement in the microcirculation. Therefore, patient-tailored monitoring is essential in order to adjust treatment requirements during resuscitation in septic shock. Optimal monitoring must integrate macrocirculation (heart rate, blood pressure, cardiac output, and ultrasound images), microcirculation (videomicroscopy parameters and capillary refill time) and cellular metabolism (lactic acid, central venous blood oxygen saturation, and difference of central venous to arterial carbon dioxide partial pressure). SUMMARY: There is a dire need for high-quality studies to assess the relationships between macrocirculation, microcirculation and tissue metabolism in children with septic shock. The development of reliable and readily available microcirculation and tissue perfusion biomarkers (other than lactic acid) is also necessary to improve monitoring and treatment adjustment in such patients.

Anti-endotoxin antibodies consumption in cardiovascular collapse: Pathophysiological concerns / Consumo de anticuerpos antiendotoxina en el shock: relación etiológica

Objective Abnormal endotoxin activity in critically ill patients has been described in the absence of Gram-negative bacterial (GNB) infection. As disease severity seems to be crucial in the detection of this phenomenon, we decided to assess and compare endotoxin exposure in those patients representing the critical situation: septic shock and cardiogenic shock. Design Prospective, observational non intervention study. Setting Critical Care Department of a University tertiary hospital. Patients Cardiogenic shock (CS) and septic shock (SS) patients. Interventions None. Measurements and main results Follow-up was performed for the first three days. Inflammatory biomarkers (C-reactive protein, procalcitonin and interleuquin-6) and IgM antiendotoxin-core antibodies titter (IgM EndoCAb) were daily analyzed. Sixty-two patients were included; twenty-five patients with SS and thirty-seven with CS. Microbial etiology was established in 23 SS patients (92%) and GNB were present in 13 cases (52%). Although infection was suspected and even treated in 30 CS patients (81%), any episode could be finally confirmed. EndoCAb consumption was more intense in SS patients, although twenty-two CS patients (59.5%) had IgM anti-endotoxin value below 10th percentile range for healthy people. No statistically significant difference in endotoxin exposure was detected between Gram-positive and Gram-negative infections in the SS group. Endotoxin exposure ability to distinguish between SS and CS was moderate (AUC 0.7892, 95% IC: 0.6564–0.9218).Conclusions In the severely ill patient some mechanisms take place allowing endotoxin incursion and therefore blurring the limits of diseases pathophysiology. Our work representatively shows how exposure to endotoxin was not fully capable of distinguishing between CS and SS. (AU)

Objetivo En el paciente crítico se ha descrito una actividad incrementada de la endotoxina no asociada a infección por bacterias gramnegativas (BGN). La gravedad de la enfermedad influye en este fenómeno, por ello realizamos este estudio en el paciente crítico por antonomasia: shock séptico y cardiogénico. Diseño Estudio prospectivo, observacional, sin intervención.Lugar de estudioUnidad de Cuidados Intensivos. Pacientes Pacientes en shock cardiogénico (SC) o séptico (SS).Intervención Ninguna. Determinaciones y principales resultados Seguimiento durante los 3 primeros días. Proteína C reactiva, procalcitonina e interleucina-6, y el título de anticuerpos IgM anti-edotoxina (IgM EndoCAb) se analizaron diariamente. Se incluyó a 62 pacientes; 25 con SS y 37 con SC. La etiología fue identificada en 23 pacientes con SS (92%), los BGN estuvieron presentes en 13 casos (52%). Se sospechó e incluso trató la infección en 30 pacientes con SC, pero en ningún caso se pudo confirmar. El consumo de EndoCAb fue más intenso en los pacientes con SS, pero 22 pacientes con SC (59,5%) tuvieron unos valores por debajo del percentil 10. Los niveles de EndoCAb no fueron significativamente diferentes entre las infecciones por BGN y cocos grampositivos. La capacidad de EndoCab para diferenciar entre SC y SS resultó ser moderada (AUC 0,7892; IC del 95%, 0,6564-0,9218).Conclusiones En el paciente crítico es frecuente que la endotoxina provoque una respuesta inflamatoria y la sumación de distintos mecanismos fisiopatológicos. En este sentido, nuestro trabajo pone de manifiesto que la determinación de exposición a endotoxina no es totalmente capaz de distinguir entre los pacientes con SC y SS. (AU)

Changes of operative performance of pulse pressure variation as a predictor of fluid responsiveness in endotoxin shock.

Several limitations regarding pulse pressure variation (PPV) use have been reported. Our aim was to describe changes in the PPV operative performance as a predictor of fluid responsiveness during the development of a swine endotoxin shock model and to assess hemodynamic variables associated with PPV changes. A swine porcine endotoxin shock model was established (Escherichia Coli 055:B5 endotoxin) in 7 pigs, and 3 pigs were included in the control group. The endotoxin was infused until the mean arterial pressure (MAP) dropped below 50 mmHg (TH0); then, the model animal was reanimated with fluids and vasopressors. We performed fluid challenges every hour for 6 h. ROC curve analysis and a linear mixed model were performed. The area under the curve of PPV decreased from 0.95 (0.81-1.00) to 0.60 (0.17-1.00) at TH0. Its cutoff increased from 10.5 to 22.00% at TH0. PPV showed an inverse relationship with stroke volume, mean systemic filling pressure, MAP, and systemic vascular resistance (SVR) (p < 0.001, AIC = 111.85). The PPV operative performance as a predictor of fluid responsiveness decreased with the progression of shock. This could lead to an inverse association between PPV and the following variables: MAP and SVR.

Optimizing left ventricular-arterial coupling during the initial resuscitation in septic shock - a pilot prospective randomized study.

BACKGROUND: Left ventricular-arterial coupling (VAC), defined as the ratio of effective arterial elastance (Ea) to left ventricular end-systolic elastance (Ees), has been extensively described as a key determinant of cardiovascular work efficacy. Previous studies indicated that left ventricular-arterial uncoupling was associated with worse tissue perfusion and increased mortality in shock patients. Therefore, this study aims to investigate whether a resuscitation algorithm based on optimizing left VAC during the initial resuscitation can improve prognosis in patients with septic shock. METHODS: This pilot study was conducted in an intensive care unit (ICU) of a tertiary teaching hospital in China. A total of 83 septic shock patients with left ventricular-arterial uncoupling (i.e., the Ea/Ees ratio ≥ 1.36) were randomly assigned to receive usual care (usual care group, n = 42) or an algorithm-based resuscitation that attempt to reduce the Ea/Ees ratio to 1 within the first 6 h after randomization (VAC-optimized group, n = 41). The left VAC was evaluated by transthoracic echocardiography every 2 h during the study period. The primary endpoint was 28-days mortality. The secondary endpoints included lactate clearance rate, length of ICU stay, and duration of invasive mechanical ventilation (IMV). RESULTS: Eighty-two patients (98.8%) completed the study and were included in the final analysis. The Ea/Ees ratio was reduced in both groups, and the decrease in Ea/Ees ratio in the VAC-optimized group was significantly greater than that in the usual care group [median (interquartile range), 0.39 (0.26, 0.45) vs. 0.1 (0.06, 0.22); P < 0.001]. Compared with the usual care group, the VAC-optimized group likely exhibited the potential to reduce the 28-days mortality (33% vs. 50%; log-rank hazard ratio = 0.526, 95% confidence interval: 0.268 to 1.033). Moreover, the VAC-optimized group had a higher lactate clearance rate than the usual care group [27.7 (11.9, 45.7) % vs. 18.3 (- 5.7, 32.1) %; P = 0.038]. No significant difference was observed in terms of the length of ICU stay or duration of IMV. CONCLUSIONS: During the initial resuscitation of septic shock, optimizing left ventricular-arterial coupling was associated with improved lactate clearance, while likely having a beneficial effect on prognosis. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR1900024031 . Registered 23 June 2019 - Retrospectively registered.

Criteria for Pediatric Sepsis-A Systematic Review and Meta-Analysis by the Pediatric Sepsis Definition Taskforce.

OBJECTIVE: To determine the associations of demographic, clinical, laboratory, organ dysfunction, and illness severity variable values with: 1) sepsis, severe sepsis, or septic shock in children with infection and 2) multiple organ dysfunction or death in children with sepsis, severe sepsis, or septic shock. DATA SOURCES: MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials were searched from January 1, 2004, and November 16, 2020. STUDY SELECTION: Case-control studies, cohort studies, and randomized controlled trials in children greater than or equal to 37-week-old postconception to 18 years with suspected or confirmed infection, which included the terms "sepsis," "septicemia," or "septic shock" in the title or abstract. DATA EXTRACTION: Study characteristics, patient demographics, clinical signs or interventions, laboratory values, organ dysfunction measures, and illness severity scores were extracted from eligible articles. Random-effects meta-analysis was performed. DATA SYNTHESIS: One hundred and six studies met eligibility criteria of which 81 were included in the meta-analysis. Sixteen studies (9,629 patients) provided data for the sepsis, severe sepsis, or septic shock outcome and 71 studies (154,674 patients) for the mortality outcome. In children with infection, decreased level of consciousness and higher Pediatric Risk of Mortality scores were associated with sepsis/severe sepsis. In children with sepsis/severe sepsis/septic shock, chronic conditions, oncologic diagnosis, use of vasoactive/inotropic agents, mechanical ventilation, serum lactate, platelet count, fibrinogen, procalcitonin, multi-organ dysfunction syndrome, Pediatric Logistic Organ Dysfunction score, Pediatric Index of Mortality-3, and Pediatric Risk of Mortality score each demonstrated significant and consistent associations with mortality. Pooled mortality rates varied among high-, upper middle-, and lower middle-income countries for patients with sepsis, severe sepsis, and septic shock (p < 0.0001). CONCLUSIONS: Strong associations of several markers of organ dysfunction with the outcomes of interest among infected and septic children support their inclusion in the data validation phase of the Pediatric Sepsis Definition Taskforce.

Association Between Hyperlactatemia, Perfusional Parameters, and Lymphocyte Mitochondrial Dysfunction in Septic Shock Patients.

INTRODUCTION: In septic shock, mitochondrial dysfunction, and hypoperfusion are the main triggers of multi-organ failure. Little is known about the crosstalk between mitochondrial dysfunction and hemodynamic alterations, especially in the post-resuscitation phase. Here, we assess whether hypoperfusion and lactate levels are associated with oxygen consumption linked to mitochondrial bioenergetic activity in lymphocytes of patients admitted with septic shock. PATIENTS AND METHODS: Prospective cohort study in patients with septic shock defined as the requirement of vasopressors to maintain a mean arterial pressure 65 mm Hg after initial fluid administration. Basal mitochondrial and Complex I respiration was measured to evaluate mitochondrial activity. Both variables and capillary refill time were compared with arterial lactate post-fluid resuscitation. We also compared mitochondrial activity measurements between patients with and without hypoperfusion status. RESULTS: A total of 90 patients were included in analysis. The median arterial lactate at the time of septic shock diagnosis was 2.0 mmol/Dl (IQR 1.3-3.0). Baseline respiration at the time of septic shock diagnosis was correlated with lactate (Spearman -0.388, 95% CI -0.4893 to -0.1021; P = 0.003), as well as Complex I respiration (Spearman -0.403, 95% CI -0.567 to -0.208; P < 0.001). Patients with hypoperfusion status had no difference in basal respiration when compared with patients who did not have hypoperfusion status (P = 0.22) nor in Complex I respiration (P = 0.09). CONCLUSION: Changes in lymphocytic mitochondrial metabolism are associated with post-resuscitation arterial lactate in septic shock; however, they are not associated with the presence of a hypoperfusional status. In this scenario, it is therefore suggested that systemic perfusion and mitochondrial metabolism have different courses.

Association between albumin infusion and outcomes in patients with acute kidney injury and septic shock.

Septic shock with acute kidney injury (AKI) is common in critically ill patients. Our aim was to evaluate the association between albumin infusion and outcomes in patients with septic shock and AKI. Medical Information Mart for Intensive Care (MIMIC)-III was used to identify patients with septic shock and AKI. Propensity score matching (PSM) was employed to balance the baseline differences. Cox proportional hazards model, Wilcoxon rank-sum test, and logistic regression were utilized to determine the associations of albumin infusion with mortality, length of stay, and recovery of kidney function, respectively. A total of 2861 septic shock patients with AKI were studied, including 891 with albumin infusion, and 1970 without albumin infusion. After PSM, 749 pairs of patients were matched. Albumin infusion was associated with improved 28-day survival (HR 0.72; 95% CI 0.59-0.86; P = 0.002), but it was not difference in 90-day mortality between groups (HR 0.94; 95% CI 0.79-1.12; P = 0.474). Albumin infusion was not associated with the renal function recovery (HR 0.91; 95% CI 0.73-1.13; P = 0.393) in either population. Nevertheless, subgroup analysis showed that albumin infusion was distinctly associated with reduced 28-day mortality in patients with age > 60 years. The results need to be validated in more randomized controlled trials.

Association between enterocyte injury and fluid balance in patients with septic shock: a post hoc exploratory analysis of a prospective observational study.

BACKGROUND: The required fluid volume differs among patients with septic shock. Enterocyte injury caused by shock may increase the need for fluid by triggering a systematic inflammatory response or an ischemia-reperfusion injury in the presence of intestinal ischemia/necrosis. This study aimed to evaluate the association between enterocyte injury and positive fluid balance in patients with septic shock. METHODS: This study was a post hoc exploratory analysis of a prospective observational study that assessed the association between serum intestinal fatty acid-binding protein, a biomarker of enterocyte injury, and mortality in patients with septic shock. Intestinal fatty acid-binding protein levels were recorded on intensive care unit admission, and fluid balance was monitored from intensive care unit admission to Day 7. The association between intestinal fatty acid-binding protein levels at admission and the infusion balance during the early period after intensive care unit admission was evaluated. Multiple linear regression analysis, with adjustments for severity score and renal function, was performed. RESULTS: Overall, data of 57 patients were analyzed. Logarithmically transformed intestinal fatty acid-binding protein levels were significantly associated with cumulative fluid balance per body weight at 24 and 72 h post-intensive care unit admission both before (Pearson's r = 0.490 [95% confidence interval: 0.263-0.666]; P < 0.001 and r = 0.479 [95% confidence interval: 0.240-0.664]; P < 0.001, respectively) and after (estimate, 14.4 [95% confidence interval: 4.1-24.7]; P = 0.007 and estimate, 26.9 [95% confidence interval: 11.0-42.7]; P = 0.001, respectively) adjusting for severity score and renal function. CONCLUSIONS: Enterocyte injury was significantly associated with cumulative fluid balance at 24 and 72 h post-intensive care unit admission. Enterocyte injury in patients with septic shock may be related to excessive fluid accumulation during the early period after intensive care unit admission.

Respiratory Drive in Patients with Sepsis and Septic Shock: Modulation by High-flow Nasal Cannula.

BACKGROUND: Experimental and pilot clinical data suggest that spontaneously breathing patients with sepsis and septic shock may present increased respiratory drive and effort, even in the absence of pulmonary infection. The study hypothesis was that respiratory drive and effort may be increased in septic patients and correlated with extrapulmonary determinant and that high-flow nasal cannula may modulate drive and effort. METHODS: Twenty-five nonintubated patients with extrapulmonary sepsis or septic shock were enrolled. Each patient underwent three consecutive steps: low-flow oxygen at baseline, high-flow nasal cannula, and then low-flow oxygen again. Arterial blood gases, esophageal pressure, and electrical impedance tomography data were recorded toward the end of each step. Respiratory effort was measured as the negative swing of esophageal pressure (ΔPes); drive was quantified as the change in esophageal pressure during the first 500 ms from start of inspiration (P0.5). Dynamic lung compliance was calculated as the tidal volume measured by electrical impedance tomography, divided by ΔPes. The results are presented as medians [25th to 75th percentile]. RESULTS: Thirteen patients (52%) were in septic shock. The Sequential Organ Failure Assessment score was 5 [4 to 9]. During low-flow oxygen at baseline, respiratory drive and effort were elevated and significantly correlated with arterial lactate (r = 0.46, P = 0.034) and inversely with dynamic lung compliance (r = -0.735, P < 0.001). Noninvasive support by high-flow nasal cannula induced a significant decrease of respiratory drive (P0.5: 6.0 [4.4 to 9.0] vs. 4.3 [3.5 to 6.6] vs. 6.6 [4.9 to 10.7] cm H2O, P < 0.001) and effort (ΔPes: 8.0 [6.0 to 11.5] vs. 5.5 [4.5 to 8.0] vs. 7.5 [6.0 to 12.6] cm H2O, P < 0.001). Oxygenation and arterial carbon dioxide levels remained stable during all study phases. CONCLUSIONS: Patients with sepsis and septic shock of extrapulmonary origin present elevated respiratory drive and effort, which can be effectively reduced by high-flow nasal cannula.

Comparison of norepinephrine, dopamine and dobutamine combined with enteral nutrition in the treatment of elderly patients harboring sepsis.

The present study was performed in order to investigate the safety and efficacy of different vasoactive drugs combined with enteral nutrition in terms of treating elderly patients with sepsis. A total of 75 elderly patients with sepsis treated with enteral nutrition in our hospital were randomly divided into three groups: group A (n = 25), group B (n = 25) and group C (n = 25). The three groups were treated with dopamine, dobutamine and norepinephrine respectively. One week after treatment, the therapeutic effects of the three groups were compared, the vascular elastic indexes, hemodynamic indexes and levels of inflammatory factors of the three groups were measured. After treatment, the clinical effective rate of group C was evidently higher than that of group A and group B. The vascular elasticity coefficient and stiffness coefficient in group C were significantly lower than those in group A and group B, and the arterial compliance in group C was significantly higher than that in group A and group B (P < 0.05). The levels of MAP and PVRI in group C were significantly higher than those in group A and B, and the levels of CI, CVP and HR in group C were significantly lower than those in group A and group B (P < 0.05). Norepinephrine elicited greater effects in terms of improving hemodynamic indexes, vascular elasticity and reducing the level of inflammatory factors compared with dopamine and dobutamine in elderly patients harboring sepsis.

The effect of norepinephrine on common carotid artery blood flow in septic shock patients.

This study was designed to evaluate the hemodynamic effect of norepinephrine (NE) on the peak systolic velocity (PSV), diameter, and blood flow of the common carotid artery (CCA) using the point-of-care ultrasound (POCUS) in patients with septic shock. The study involved patients above 18 years old with septic shock. Arterial monitoring, carotid ultrasonography, and transthoracic echocardiography were performed before NE administration (T0). When the mean arterial pressure exceeded 65 mmHg after NE administration (T1), the measurement was repeated. Twenty-four patients (median age 67 [interquartile range: 54-77] years; 42% female) with septic shock were examined in this study. Before (T0) and after (T1) NE administration, the PSV (mean, standard deviation [SD]) changed from 85.3 (21.1) cm/s to 83.5 (23.5) cm/s (p = 0.417); this change was not significant. However, the diameter and blood flow of the CCA increased significantly from 0.6 (0.09) cm and 0.75 (0.27) L/min to 0.66 (0.09) cm and 0.85 (0.27) L/min, respectively (p < 0.001). The diameter of the left ventricular outflow tract (LVOT) remained unchanged, but the velocity time integral of the LVOT increased significantly from 21.7 (4.39) cm to 23.6 (5.14) cm. There was no significant correlation between changes in blood flow of the CCA and changes in cardiac output (coefficient -0.365, p = 0.079). In conclusion, NE increased the diameter and blood flow of the CCA significantly, without changing the PSV in patients with septic shock.

Norepinephrine potentiates the efficacy of volume expansion on mean systemic pressure in septic shock.

BACKGROUND: Through venous contraction, norepinephrine (NE) increases stressed blood volume and mean systemic pressure (Pms) and exerts a "fluid-like" effect. When both fluid and NE are administered, Pms may not only result from the sum of the effects of both drugs. Indeed, norepinephrine may enhance the effects of volume expansion: because fluid dilutes into a more constricted, smaller, venous network, fluid may increase Pms to a larger extent at a higher than at a lower dose of NE. We tested this hypothesis, by mimicking the effects of fluid by passive leg raising (PLR). METHODS: In 30 septic shock patients, norepinephrine was decreased to reach a predefined target of mean arterial pressure (65-70 mmHg by default, 80-85 mmHg in previously hypertensive patients). We measured the PLR-induced increase in Pms (heart-lung interactions method) under high and low doses of norepinephrine. Preload responsiveness was defined by a PLR-induced increase in cardiac index ≥ 10%. RESULTS: Norepinephrine was decreased from 0.32 [0.18-0.62] to 0.26 [0.13-0.50] µg/kg/min (p < 0.0001). This significantly decreased the mean arterial pressure by 10 [7-20]% and Pms by 9 [4-19]%. The increase in Pms (∆Pms) induced by PLR was 13 [9-19]% at the higher dose of norepinephrine and 11 [6-16]% at the lower dose (p < 0.0001). Pms reached during PLR at the high dose of NE was higher than expected by the sum of Pms at baseline at low dose, ∆Pms induced by changing the norepinephrine dose and ∆Pms induced by PLR at low dose of NE (35.6 [11.2] mmHg vs. 33.6 [10.9] mmHg, respectively, p < 0.01). The number of preload responders was 8 (27%) at the high dose of NE and 15 (50%) at the low dose. CONCLUSIONS: Norepinephrine enhances the Pms increase induced by PLR. These results suggest that a bolus of fluid of the same volume has a greater haemodynamic effect at a high dose than at a low dose of norepinephrine during septic shock.

Venoarterial extracorporeal membrane oxygenation as mechanical circulatory support in adult septic shock: a systematic review and meta-analysis with individual participant data meta-regression analysis.

BACKGROUND: While recommended by international societal guidelines in the paediatric population, the use of venoarterial extracorporeal membrane oxygenation (VA ECMO) as mechanical circulatory support for refractory septic shock in adults is controversial. We aimed to characterise the outcomes of adults with septic shock requiring VA ECMO, and identify factors associated with survival. METHODS: We searched Pubmed, Embase, Scopus and Cochrane databases from inception until 1st June 2021, and included all relevant publications reporting on > 5 adult patients requiring VA ECMO for septic shock. Study quality and certainty in evidence were assessed using the appropriate Joanna Briggs Institute checklist, and the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach, respectively. The primary outcome was survival to hospital discharge, and secondary outcomes included intensive care unit length of stay, duration of ECMO support, complications while on ECMO, and sources of sepsis. Random-effects meta-analysis (DerSimonian and Laird) were conducted. DATA SYNTHESIS: We included 14 observational studies with 468 patients in the meta-analysis. Pooled survival was 36.4% (95% confidence interval [CI]: 23.6%-50.1%). Survival among patients with left ventricular ejection fraction (LVEF) < 20% (62.0%, 95%-CI: 51.6%-72.0%) was significantly higher than those with LVEF > 35% (32.1%, 95%-CI: 8.69%-60.7%, p = 0.05). Survival reported in studies from Asia (19.5%, 95%-CI: 13.0%-26.8%) was notably lower than those from Europe (61.0%, 95%-CI: 48.4%-73.0%) and North America (45.5%, 95%-CI: 16.7%-75.8%). GRADE assessment indicated high certainty of evidence for pooled survival. CONCLUSIONS: When treated with VA ECMO, the majority of patients with septic shock and severe sepsis-induced myocardial depression survive. However, VA ECMO has poor outcomes in adults with septic shock without severe left ventricular depression. VA ECMO may be a viable treatment option in carefully selected adult patients with refractory septic shock.

Prognostic value of baseline carotid blood flow in critically ill children with septic shock.

BACKGROUND AND AIM: Hemodynamic monitoring and cardiac output (CO) assessment in the ICU have been trending toward less invasive methods. Carotid blood flow (CBF) was suggested as a candidate for CO assessment. The present study aimed to test the value of carotid artery ultrasound analysis in prediction of mortality in pediatric patients with septic shock. METHODOLOGY/PRINCIPAL FINDING: Forty children with septic shock were included in the study. Upon admission, patients were subjected to careful history taking and thorough clinical examination. The consciousness level was assessed by the Glasgow Coma Scale (GCS). Laboratory assessment included complete blood count, C-reactive protein, arterial blood gases, serum electrolytes, and liver and kidney function tests. Electrical cardiometry was used to evaluate hemodynamic parameters. Patients were also subjected to transthoracic 2-D echocardiography. CBF was evaluated using GE Vivid S5 ultrasound device through dedicated software. At the end of study, 14 patients (35.0%) died. It was found that survivors had significantly higher CBF when compared non-survivors [median (IQR): 166.0 (150.0-187.3) versus 141.0 (112.8-174.3), p = 0.033]. In addition, it was noted that survivors had longer ICU stay when compared with non-survivors [16.5 (9.8-31.5) versus 6.5 (3.0-19.5) days, p = 0.005]. ROC curve analysis showed that CBF could significantly distinguish survivors from non-survivors [AUC (95% CI): 0.3 (0.11-0.48), p = 0.035] (Fig 2). Univariate logistic regression analysis identified type of shock [OR (95% CI): 28.1 (4.9-162.4), p<0.001], CI [OR (95% CI): 0.6 (0.43-0.84), p = 0.003] and CBF [OR (95% CI): 0.98 (0.96-0.99), p = 0.031]. However, in multivariate analysis, only type of shock significantly predicted mortality. CONCLUSIONS: CBF assessment may be a useful prognostic marker in children with septic shock.

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.

An 80-Year-Old Man With Persistent Enterococcus faecalis Bacteremia.

CASE PRESENTATION: An 80-year old man presented to the ED after being found down in his home. He had gone to the restroom to perform straight catheterization, as he normally does for his enlarged prostate, and was found slumped over and confused. On arrival to the ED, he was found to be in atrial fibrillation with rapid ventricular response, febrile, and hypotensive. CT imaging of his head, chest, and abdomen-pelvis was obtained. He was started on broad-spectrum antibiotics and norepinephrine infusion for presumed urinary septic shock and admitted to the medical critical care unit for further management.

Mechanistic insights into cell-free hemoglobin-induced injury during septic shock.

Cell-free hemoglobin (CFH) levels are elevated in septic shock and are higher in nonsurvivors. Whether CFH is only a marker of sepsis severity or is involved in pathogenesis is unknown. This study aimed to investigate whether CFH worsens sepsis-associated injuries and to determine potential mechanisms of harm. Fifty-one, 10-12 kg purpose-bred beagles were randomized to receive Staphylococcus aureus intrapulmonary challenges or saline followed by CFH infusions (oxyhemoglobin >80%) or placebo. Animals received antibiotics and intensive care support for 96 h. CFH significantly increased mean pulmonary arterial pressures and right ventricular afterload in both septic and nonseptic animals, effects that were significantly greater in nonsurvivors. These findings are consistent with CFH-associated nitric oxide (NO) scavenging and were associated with significantly depressed cardiac function, and worsened shock, lactate levels, metabolic acidosis, and multiorgan failure. In septic animals only, CFH administration significantly increased mean alveolar-arterial oxygenation gradients, also to a significantly greater degree in nonsurvivors. CFH-associated iron levels were significantly suppressed in infected animals, suggesting that bacterial iron uptake worsened pneumonia. Notably, cytokine levels were similar in survivors and nonsurvivors and were not predictive of outcome. In the absence and presence of infection, CFH infusions resulted in pulmonary hypertension, cardiogenic shock, and multiorgan failure, likely through NO scavenging. In the presence of infection alone, CFH infusions worsened oxygen exchange and lung injury, presumably by supplying iron that promoted bacterial growth. CFH elevation, a known consequence of clinical septic shock, adversely impacts sepsis outcomes through more than one mechanism, and is a biologically plausible, nonantibiotic, noncytokine target for therapeutic intervention.NEW & NOTEWORTHY Cell-free hemoglobin (CFH) elevations are a known consequence of clinical sepsis. Using a two-by-two factorial design and extensive physiological and biochemical evidence, we found a direct mechanism of injury related to nitric oxide scavenging leading to pulmonary hypertension increasing right heart afterload, depressed cardiac function, worsening circulatory failure, and death, as well as an indirect mechanism related to iron toxicity. These discoveries alter conventional thinking about septic shock pathogenesis and provide novel therapeutic approaches.