Noninvasive measurements of hemodynamic, autonomic and endothelial function as predictors of mortality in sepsis: A prospective cohort study

Sepsis-induced inflammatory demyelination in medullary visceral zone and cholinergic anti-inflammatory pathway: Insights from a Rat's model study

Background

Our previous studies have demonstrated that the activated Cholinergic Anti-inflammatory Pathway (CAP) effectively suppresses systemic inflammation and immunity in early sepsis. Some parameters of Heart Rate Variability (HRV) could be used to reflect the regulatory activity of CAP. However, in the early stages of severe sepsis of some patients, the inflammatory storm can still result in multiple organs dysfunction and even death, suggesting they lose CAP's modulation ability. Since CAP is part of the vagus nerve and is directly innervated by the Medullary Visceral Zone (MVZ), we can reasonably concluded that pathological changes induced by MVZ's neuroinflammation should be responsible for CAP's dysfunction in modulating systemic inflammation in early sepsis.

Methods

We conducted two independent septic experiments, the sepsis model rats were prepared by cecum ligation and puncture (CLP) method. In the first experiment, A total of 64 adult male Sprague-Dawley rats were included. Under the condition of sepsis and CAP's pharmacological activation or blockade, we investigated the MVZ's pathological changes, the functional state of key neurons including catecholaminergic and cholinergic neurons, key genes' expression such as Oligodendrocyte Transcription Factor 2 (Olig-2) mRNA, glial fibrillary acidic protein (GFAP) mRNA, and matrix metalloprotein (MMP) -9 mRNA, and CAP's activities reflected by HRV. The second experiment involved in 56 rats, through central anti-inflammation by feeding with 10 mg/ml minocycline sucrose solution as the only water source, or right vagus transection excepting for central anti-inflammation as a mean of the CAP's functional cancel, we confirmed that the neuroinflammation in MVZ affected systemic inflammation through CAP in sepsis.

Results

In the first experiment, cholinergic and catecholaminergic neurons showed significant apoptosis with reduced expressions of TH, but the expression of CHAT remained relatively unaffected in MVZ in sepsis. HRV parameters representing the tone of the vagus nerve, such as SDNN, RMSSD, HF, SD1, and SD2, did not show significant differences among the three Septic Groups, although they all decreased significantly compared to the Control Group. The expressions of GFAP mRNA and MMP-9 mRNA were up-regulated, while the expression of Olig-2 mRNA was down-regulated in the Septic Groups. Intervention of CAP had a significant effect on cholinergic and catecholaminergic neurons' apoptosis, as well as the expressions of TH/CHAT and these key genes, but had little effect on HRV in sepsis. In the second experiment, the levels of TNF-α, IL-6, in serum and MVZ were significantly increased in sepsis. Central anti-inflammatory treatment reversed these changes. However, right vagotomy abolished the central anti-inflammatory effect.

Conclusions

Our study uncovered that MVZ's neuroinflammation may play a crucial role in the uncontrolled systemic inflammation through inflammatory demyelination in MVZ, which disrupts CAP's modulation on the systemic inflammation in early sepsis.

Early Postoperative Vital Signs Predict Subsequent 90-Day Mortality After Pancreaticoduodenectomy

BACKGROUND

While complication rates after pancreaticoduodenectomy (PD) have improved in recent decades, surgical-related death remains a possibility. Postoperative vital signs offer an untapped opportunity to identify predictors of 90-day mortality.

METHODS

We performed a retrospective chart review interrogating postoperative day (POD 0-7) vital sign measurements from patients undergoing a PD at Thomas Jefferson University Hospital, Philadelphia, PA (2009-2014). Five specific vital signs were examined as predictors of mortality: temperature, heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure. Statistical analyses and logic algorithms were employed to rank vital sign parameters, with cut-points, to identify those associated with the highest risk of mortality and the most clinical relevance.

RESULTS

In our cohort, 11/750 patients (1.5%) died within 30 days of surgery, and 21/750 patients (2.8%) died within 90 days of surgery. Vital sign perturbations associated with the highest risk of mortality included mean SBP < 95 mmHg on POD 7 (odds ratio 51.46) and the mean temperature < 96.9℉ on POD 3 (odds ratio 22.63) with specificities exceeding 99%. The most clinically relevant predictor (i.e., a higher sensitivity) was DBP < 60.5 mmHg on POD 7 (odds ratio 12.45, sensitivity of 75%). These predictors remained statistically significant in a multivariable model.

CONCLUSIONS

Vital signs can be more effectively utilized to predict 90-day mortality after pancreaticoduodenectomy. Values beyond an informative threshold can potentially identify patients for more intensive monitoring with a goal of rescuing patients and preventing death.

Early passive mobilization increases vascular reactivity response in critical patients with sepsis: a quasi-experimental study

OBJECTIVE

To investigate the influence of a passive mobilization session on endothelial function in patients with sepsis.

METHODS

This was a quasi-experimental double-blind and single-arm study with a pre- and postintervention design. Twenty-five patients with a diagnosis of sepsis who were hospitalized in the intensive care unit were included. Endothelial function was assessed at baseline (preintervention) and immediately postintervention by brachial artery ultrasonography. Flow mediated dilatation, peak blood flow velocity and peak shear rate were obtained. Passive mobilization consisted of bilateral mobilization (ankles, knees, hips, wrists, elbows and shoulders), with three sets of ten repetitions each, totaling 15 minutes.

RESULTS

After mobilization, we found increased vascular reactivity function compared to preintervention: absolute flow-mediated dilatation (0.57mm ± 0.22 versus 0.17mm ± 0.31; p < 0.001) and relative flow-mediated dilatation (17.1% ± 8.25 versus 5.08% ± 9.16; p < 0.001). Reactive hyperemia peak flow (71.8cm/s ± 29.3 versus 95.3cm/s ± 32.2; p < 0.001) and shear rate (211s ± 113 versus 288s ± 144; p < 0.001) were also increased.

CONCLUSION

A passive mobilization session increases endothelial function in critical patients with sepsis. Future studies should investigate whether a mobilization program can be applied as a beneficial intervention for clinical improvement of endothelial function in patients hospitalized due to sepsis.

The Association between Inflammatory Biomarkers and Cardiovascular Autonomic Dysfunction after Bacterial Infection

Heart rate variability (HRV) is a known measure of cardiac autonomic function. A cardiovascular autonomic dysfunction (CAD), measured as changes in HRV, is usually presented after an infectious process. The aim of the present study is to assess the association between serum inflammatory markers and CAD. For this purpose, 50 volunteers (13 of them recovering from an infection) were recruited and followed-up for 6 weeks. Their serum inflammatory biomarkers (CRP, IL1, IL4, IL6, IL10, and TNFalpha) were quantified throughout those weeks, along with their HRV resting, in response to the Valsalva maneuver, metronome breathing, standing and sustained handgrip. The correlation of within-subject changes in both HRV and inflammatory biomarkers was assessed to evaluate the concurrent changes. An inverse within-subject correlation was found between CRP and HRV in response to the Valsalva maneuver (rho (95% CI): −0.517 (−0.877 to −0.001); p = 0.032) and HRV standing (rho (95% CI): −0.490 (−0.943 to −0.036); p = 0.034). At the beginning, increased values of CRP are found along with reduced levels of HRV. Then, the CRP was reduced, accompanied by an improvement (increase) in HRV. These results suggest that CRP is a potential marker of CAD. Whether it is the cause, the consequence or a risk indicator non-causally associated is still to be determined.

Exploration of autonomic regulation reflecting on pathophysiological change of sepsis: a prospective observational study

Aim

It remains unclear how autonomic regulation modulates pathophysiological changes of sepsis. This study aims to analyze and clarify those in patients with suspected sepsis.

Methods

In this single‐centered, prospective, observational study, adult patients who had an infection, a quick Sequential Organ Failure Assessment score of 2 or more at the emergency department, and underwent intensive care were screened. Heart rate variability (HRV) and serum adrenaline were measured immediately after arrival. The primary outcome was defined as vasopressor dependence during 48 h after arrival.

Results

A total of 63 patients were included. All the patients had SOFA score of 2 or more on admission. Vasopressor dependence, renal replacement therapy, and in‐hospital mortality were associated with higher adrenaline (which reflects sympathetic adrenergic system activity). Bacteremia was associated with lower high‐frequency components of HRV (parasympathetic nerve activity). The HRV parameter of sympathetic nerve activity had no significant association with the outcomes. In the multivariate logistic regression model adjusted for age and sex, vasopressor dependence remained associated with higher adrenaline (cut‐off 0.11 ng/mL, odds ratio 9.71, 95% confidence interval 2.55–37; P = 0.000874), and lower high‐frequency components with bacteremia (17.2 ms², odds ratio 4.86, 95% confidence interval 1.36–17.4; P = 0.0152). There were no significant correlations between parameters of HRV and serum adrenaline.

Conclusion

Hypoperfusion, organ dysfunction, and in‐hospital mortality were associated with an increased sympathetic adrenergic activity. Bacteremia was associated with decreased parasympathetic nerve activity. The autonomic regulator may involve a multilayered and differentiated modulating process for sepsis.

Effectiveness of Different Physiotherapy Protocols in Children in the Intensive Care Unit: A Randomized Clinical Trial

PURPOSE

This study aimed to investigate the effectiveness of different physical therapy protocols on the autonomic modulation of heart rate, time of invasive mechanical ventilation (IMV), and length of hospital stay.

METHODS

This was a randomized clinical study with 20 children on IMV in an intensive care unit (ICU), between July 2018 and September 2019. The control group (n = 10) performed the hospital's physical therapy protocol and the experimental group (n = 10) performed the physical therapy protocol based on physical exercise.

RESULTS

Higher values of heart rate variability were found in the experimental group, both in individual and intergroup analyses. There was a significant reduction in the time of IMV and ICU stay.

CONCLUSION

There was an improvement in heart rate variability, reduced time on mechanical ventilation and length of stay in the ICU in individuals who performed the study protocol.

Dysfunction of the Autonomic Nervous System and its Role in the Pathogenesis of Septic Critical Illness (Review)

Dysfunction of the autonomic nervous system (ANS) of the brain in sepsis can cause severe systemic inflammation and even death. Numerous data confirmed the role of ANS dysfunction in the occurrence, course, and outcome of systemic sepsis. The parasympathetic part of the ANS modifies the inflammation through cholinergic receptors of internal organs, macrophages, and lymphocytes (the cholinergic anti-inflammatory pathway). The sympathetic part of ANS controls the activity of macrophages and lymphocytes by influencing β2-adrenergic receptors, causing the activation of intracellular genes encoding the synthesis of cytokines (anti-inflammatory beta2-adrenergic receptor interleukin-10 pathway, β2AR–IL-10). The interaction of ANS with infectious agents and the immune system ensures the maintenance of homeostasis or the appearance of a critical generalized infection. During inflammation, the ANS participates in the inflammatory response by releasing sympathetic or parasympathetic neurotransmitters and neuropeptides. It is extremely important to determine the functional state of the ANS in critical conditions, since both cholinergic and sympathomimetic agents can act as either anti- or pro-inflammatory stimuli.

Patterns of vascular response immediately after passive mobilization in patients with sepsis: an observational transversal study

Sepsis is a serious organ dysfunction leading to endothelial damage in critical patients. Physiologically, there is an augment of vascular diameter in response to increased vascular blood flow and shear stress stimulus. However, the pattern of vascular response in face of passive mobilization (PM), an early mobilization physical strategy, has not yet been explored in patients with sepsis. To explore patterns of vascular response to PM and associations with clinical and cardiovascular profile in patients with sepsis. Cross-sectional, single-arm study. Thirty-two patients diagnosed with sepsis were enrolled. Vascular response was assessed by flow-mediated dilation (FMD) using brachial artery ultrasound, before and after PM. The PM (to assess the response pattern) and SR (shear rate) were also calculated. PM protocol consisted of knees, hips, wrists, elbows, shoulders, dorsiflexion/plantar flexion movements 3 × 10 repetitions each (15 min). Arterial stiffness was assessed by Sphygmocor®, by analyzing the morphology and pulse wave velocity. Cardiac autonomic modulation (CAM) was assessed by analyzing heart rate variability indexes (mean HR, RMSSD, LF, HF, ApEn, SampEn, DFA). Different vascular responses were observed after PM: (1) increased vascular diameter (responders) (n = 13, %FMD = 11.89 ± 5.64) and (2) reduced vascular diameter (non-responders) (n = 19, %FMD= -7.42 ± 6.44). Responders presented a higher non-linear DFA2 index (p = 0.02). There was a positive association between FMD and DFA (r = 0.529; p = 0.03); FMD and SampEn (r = 0.633; p < 0.01). A negative association was identified between FMD and LF (Hz) (r= -0.680; p < 0.01) and IL-6 (r= -0.469; p = 0.037) and SR and CRP (r= -0.427; p = 0.03).

Endothelial function provides early prognostic information in patients with COVID-19: A cohort study

Background

The prothrombotic phenotype and diffuse intravascular coagulation observed in COVID-19 reflect endothelial dysfunction, which is linked to blood flow delivery deficiencies and cardiovascular risk. Assessments of detect vascular deficiencies among newly diagnosed and hospitalized patients due to COVID-19 have yet to be determined.

Objective

To assess endothelial function characteristics in relation to length of hospitalization and mortality in patients diagnosed with COVID-19 and compare to patients without COVID-19.

Methods

A prospective observational study involving 180 patients with confirmed COVID-19 (COVID-19 group) or suspected and ruled out COVID-19 (Non-COVID-19 group). Clinical evaluation and flow mediated vasodilation (FMD) were performed between the first 24–48 h of hospitalization. Patients were followed until death or discharge.

Results

We evaluated 98 patients (COVID-19 group) and 82 (Non-COVID-19 group), COVID-19 group remained hospitalized longer and more deaths occurred compared to the Non-COVID-19 group (p = 0.01; and p < 0.01). Patients in COVID-19 group also had a significantly greater reduction in both FMDmm and FMD% (p < 0.01 in both). We found that absolute FMD≤0.26 mm and relative FMD≤3.43% were the ideal cutoff point to predict mortality and longer hospital stay. In Kaplan Meyer's analysis patients had a high probability of death within a period of up to 10 days of hospitalization.

Conclusion

Patients hospitalized for COVID-19 present endothelial vascular dysfunction early, remained hospitalized longer and had a higher number of deaths, when compared with patients without COVID-19.

Severity of illness affecting the length of stay and outcomes in patients admitted to intensive care units, Iran, 2019

BACKGROUND

Length of stay (LOS) and patients' outcome are two important indicators in intensive care units (ICUs). The severity of illness influences these variables and could have a predictive value in clinical settings. The impact of severity of illness on the LOS and outcomes in patients admitted to ICUs was investigated in a selected hospital in Iran in 2019.

MATERIALS AND METHODS

This research was a descriptive longitudinal study. Data were prospectively collected on 150 patients. The sequential organ failure assessment (SOFA) score, LOS, and demographic variables of the patients were recorded. Abbreviated mental test and Barthel index measuring activities of daily living questionnaires were completed at the time of the discharge from ICU and 1 month later to show the patient outcomes. Data analysis was performed using Chi-square test, t-test, analysis of variance, Pearson's correlation, and linear and ordinal logistic regression with SPSS software version 16.

RESULTS

The mean of LOS was 11.21 ± 10.54 days. 24.7% of the patients were discharged from ICUs with optimal recovery, 49.3% with poor recovery, and 26% died in ICUs. One month after discharge, 67.6% of patients had optimal recovery, 24.3% had poor recovery, and 8.1% died. The SOFA score had a significant relation with LOS and patient outcomes in discharge and 1 month later. All the patients with SOFA score <5 survived, and all the patients with SOFA score more than 12 died.

CONCLUSIONS

The severity of illness had a significant relation with LOS and patient outcomes in the time of the discharge from ICU and 1 month later. It seems that the initial SOFA score of 12 and higher can be suggested as a cutoff point for poor prognosis in ICU patients.

Cardiac and Brainstem Neuroinflammatory Pathways Account for Androgenic Incitement of Cardiovascular and Autonomic Manifestations in Endotoxic Male Rats

ABSTRACT

Inconsistent reports are available on the role of testosterone in end-organ damage caused by endotoxemia. Here, pharmacologic, surgical, and molecular studies were employed to assess the testosterone modulation of cardiovascular, autonomic, and peripheral and central inflammatory derangements caused by endotoxemia. Studies were performed in conscious male rats preinstrumented with femoral indwelling catheters for the measurement of blood pressure and subjected to castration or pharmacologic interventions that interrupt the biosynthetic cascade of testosterone. Compared with the effects of lipopolysaccharide (10 mg/kg intravenously) in sham operated rats, 2-week castration reduced the lipopolysaccharide-evoked (1) falls in blood pressure, (2) decreases in time- and frequency-domain indices of heart rate variability, (3) shifts in spectral measures of cardiac sympathovagal balance toward parasympathetic dominance, and (4) increases in protein expressions of toll-like receptor-4 and monocyte chemoattractant protein-1 in heart and medullary neurons of the nucleus tractus solitarius and rostral ventrolateral medulla. While the ameliorating actions of castration on endotoxic cardiovascular manifestations were maintained after testosterone replacement, the concomitant inflammatory signals were restored to near-sham levels. The favorable influences of castration on inflammatory and cardiovascular abnormalities of endotoxemia were replicated in intact rats pretreated with degarelix (gonadotropin-releasing hormone receptor blocker) or finasteride (5α-reductase inhibitor) but not formestane (aromatase inhibitor). The data signifies the importance of androgens and its biosynthetic enzymes in cardiovascular and autonomic insults induced by the endotoxic inflammatory response. Clinically, the interruption of testosterone biosynthesis could offer a potential strategy for endotoxemia management.

Overview of the Assessment of Endothelial Function in Humans

The endothelium is recognized to play an important role in various physiological functions including vascular tone, permeability, anticoagulation, and angiogenesis. Endothelial dysfunction is increasingly recognized to contribute to pathophysiology of many disease states, and depending on the disease stimuli, mechanisms underlying the endothelial dysfunction may be markedly different. As such, numerous techniques to measure different aspects of endothelial dysfunction have been developed and refined as available technology improves. Current available reviews on quantifying endothelial dysfunction generally concentrate on a single aspect of endothelial function, although diseases may affect more than one aspect of endothelial function. Here, we aim to provide an overview on the techniques available for the assessment of the different aspects of endothelial function in humans, human tissues or cells, namely vascular tone modulation, permeability, anticoagulation and fibrinolysis, and the use of endothelial biomarkers as predictors of outcomes.

Peripheral arterial tonometry as a method of measuring reactive hyperaemia correlates with organ dysfunction and prognosis in the critically ill patient: a prospective observational study

Predictions of mortality may help in the selection of patients who benefit from intensive care. Endothelial dysfunction is partially responsible for many of the organic dysfunctions in critical illness. Reactive hyperaemia is a vascular response of the endothelium that can be measured by peripheral arterial tonometry (RH-PAT). We aimed to assess if reactive hyperaemia is affected by critical illness and if it correlates with outcomes. Prospective study with a cohort of consecutive patients admitted to an Intensive Care Unit. RH-PAT was accessed on admission and on the 7th day after admission. Early and late survivors were compared to non-survivors. The effect of RH-PAT variation on late mortality was studied by a logistic regression model. The association between RH-PAT and severity scores and biomarkers of organic dysfunction was investigated by multivariate analysis. 86 patients were enrolled. Mean ln(RHI) on admission was 0.580 and was significantly lower in patients with higher severity scores (p < 0.01) and early non-survivors (0.388; p = 0.027). The model for prediction of early-mortality estimated that each 0.1 decrease in ln(RHI) increased the odds for mortality by 13%. In 39 patients, a 2nd RH-PAT measurement was performed on the 7th day. The variation of ln(RHI) was significantly different between non-survivors and survivors (− 24.2% vs. 63.9%, p = 0.026). Ln(RHI) was significantly lower in patients with renal and cardiovascular dysfunction (p < 0.01). RH-PAT is correlated with disease severity and seems to be an independent marker of early mortality, cardiovascular and renal dysfunctions. RH-PAT variation predicts late mortality. There appears to be an RH-PAT impairment in the acute phase of severe diseases that may be reversible and associated with better outcomes.

A narrative review of heart rate and variability in sepsis

Clinicians face challenges in the timely diagnosis and management of pediatric sepsis. Pediatric heart rate has been incorporated into early warning systems and studied as a predictor for critical illness. We aim to review: (I) the role of heart rate in pediatric warning systems and (II) the role of heart rate variability (HRV) in adult and neonatal sepsis, with a focus on its potential applications in pediatrics. We conducted a literature search for papers published up to December 2019 on the utility of heart rate and HRV analysis in the diagnosis and management of sepsis, using four medical databases: PubMed, Google Scholar, EMBASE and Web of Science. This review demonstrates that the clinical utility of pediatric heart rate in predicting clinical deterioration is limited by the lack of consensus among warning systems, consensus-based guidelines, and evidence-based studies as to what constitutes abnormal heart rate in the pediatric age group. Current studies demonstrate that abnormal heart rate itself does not adequately discriminate children with sepsis from those without. HRV analysis provides a quick and non-invasive method of assessment and can provide more information than traditional heart rate. HRV analysis has the potential to add value in identification and prognostication of adult and neonatal sepsis. With further studies to explore its role, HRV analysis has the potential to add to current tools in the diagnosis and prognosis of pediatric sepsis.