Calibrated cardiac output monitoring versus standard care for fluid management in the shocked ICU patient: a pilot randomised controlled trial.

BACKGROUND: Despite the evidence for calibrated cardiac monitored devices to determine fluid responsiveness, there is minimal evidence that the use of cardiac output monitor devices leads to an overall change in IV fluid use. We sought to investigate the feasibility of performing a randomised controlled study using calibrated cardiac output monitoring devices in shocked ICU patients and whether the use of these devices led to a difference in total volume of IV fluid administered. METHODS: We performed a single-centre non-blinded randomised controlled study which included patients who met the clinical criteria for shock on admission to ICU. Patients were divided into two groups (cardiac output monitors or standard) by block randomisation. Patients allocated to the cardiac output monitor all received EV1000 with Volume View sets. Daily intravenous fluid administration and cumulative fluid balance was recorded for 3 days. The primary outcome assessed was the difference in daily intravenous fluid administration and cumulative fluid balance at 72 h between the two groups. We also assessed how often the clinicians used the cardiac monitor to guide fluid therapy and the different reasoning for initiating further intravenous fluids. RESULTS: Eighty patients were randomised and 37 received calibrated cardiac output monitors. We found no adverse outcomes in the use of calibrated cardiac output monitoring devices and that was feasible to perform a randomised controlled trial. There was no significant difference between the standard care group vs the cardiac monitoring group for cumulative fluid balance (2503 ± 3764 ml vs 2458 ± 3560 ml, p = 0.96). There was no significant difference between the groups for daily intravenous fluid administration on days 1, 2 or 3. In the cardiac monitored group, only 43% of the time was the EV1000 output incorporated into the decision to give further intravenous fluids. CONCLUSION: It is feasible to perform a randomised controlled trial using calibrated cardiac output monitoring devices. In addition, there was no trend to suggest that the use of a cardiac monitors leads to lower IV fluid use in the shocked patient. Further trials will require study designs to optimise the use of a cardiac output monitor to determine the utility of these devices in the shocked patient. TRIAL REGISTRATION: ANZCTR, ACTRN12618001373268. Registered 15 August 2018-retrospectively registered.

Effects of extracorporeal membrane oxygenation pump flow, backflow cannulae, mean arterial blood pressure, and pulse pressure on Doppler-derived flow velocities of the lower limbs in patients on peripheral veno-arterial extracorporeal membrane oxygenation: A pilot study.

BACKGROUND: Reported rates of limb ischaemia on peripheral veno-arterial extracorporeal membrane oxygenation (pVA ECMO) vary from 1-52%. OBJECTIVES: Primary: To explore (i) the feasibility for appropriately trained intensive care unit staff to measure Doppler derived flow velocities of the lower limbs for patients on pVA ECMO; and (ii) whether these measurements are clinically useful. Secondary: explore the relationship between ECMO pump flow, backflow cannulae (BFC) properties, mean arterial blood pressure (MAP), and pulse pressure on flow velocities. METHOD: Inclusion criteria: age>18 years, on pVA ECMO >24 hours. EXCLUSION CRITERIA: any guardianship limitations and patients without a BFC. Serial patients receiving pVA-ECMO over a 10 month period had Doppler derived flow velocities of the lower limbs sampled. Simultaneously, other pertinent parameters were recorded. 80% inclusion was considered clinically feasible. Study personnel were asked for feedback regarding the ease and usefulness of studies. RESULTS: 15 of 17 patients were included: 88% inclusion. Mean peak systolic velocity (PSV) in the cannulated limb was 31 ± 29 cm/s in the dorsalis pedis (DP) and 27 ± 18 cm/s posterior tibial (PT). Similar flows were recorded in the non-cannulated limbs (DP 34 ± 29 cm/s, PT 44 ± 36 cm/s; P > 0.05). PSV was positively correlated with pulse pressure in cannulated and non-cannulated limbs respectively (r=0.63, P < 0.05; r=0.67 and P < 0.05). There was no significant correlation between PSV and MAP. ECMO pump flow and BFC were negatively correlated with PSV (r=-0.51, P < 0.05; r=-0.43, P < 0.05). CONCLUSION: It is generally feasible for ICU staff to measure flow velocities of the lower limbs for patients on pVA ECMO. It remains unclear how clinically useful these measurements are. Doppler derived flow velocities of arteries of the lower limbs of patients on pVA ECMO appear different to non-ECMO patients. PSV in the lower limbs of patients on pVA ECMO seems to be more related to pulse pressure than to other haemodynamic parameters.

Viral Bronchiolitis is Associated With Altered Cytokine Gene Expression and Lymphocyte Activation Status.

BACKGROUND: Disease severity in viral bronchiolitis is often difficult to predict at onset, and may be related to the host immune response. Recognizing the particular immunologic features of infants who develop severe disease might offer an opportunity for developing diagnostic tools to facilitate early intervention and improve outcomes. METHODS: We compared cytokine gene expression (by real-time reverse-transcriptase polymerase chain reaction), cytokine concentrations (by enzyme-linked immunosorbent assay) and the activation status of lymphocytes (by flow cytometry) in the peripheral blood of children hospitalized with moderate and severe viral bronchiolitis and a group of age-matched controls. RESULTS: Analysis was undertaken on 57 children with viral bronchiolitis and 33 controls. Interleukin-7 mRNA expression at enrollment in peripheral blood mononuclear cells differed significantly between those with moderate and severe bronchiolitis, and correlated with both the subsequent length of hospital stay and need for supplemental oxygen therapy. Serum interleukin-10 concentration also distinguished moderate from severe disease. Participants with viral bronchiolitis demonstrated a more activated γδ-T cell phenotype (Vδ1+), but a more naive TCR αß-T cell compartment compared with controls. CONCLUSIONS: Viral bronchiolitis is characterized by a distinct pattern of cytokine expression and lymphocyte activation. These changes suggest an inadequate innate response in severe disease, and may offer potential as markers of disease severity.

Interleukin-15 is associated with disease severity in viral bronchiolitis.

Disease severity in viral bronchiolitis in infancy is difficult to predict and has been linked to host innate immunity. The study aimed to investigate the innate cytokine interleukin-15 (IL-15) as a marker of disease severity.A prospective single-centre observational study was conducted in a university-affiliated paediatric teaching hospital, comparing children (0-18 months) hospitalised for viral bronchiolitis, those admitted to the paediatric intensive care unit with severe disease and healthy age-matched controls. IL-15-related parameters were compared between groups. PCR and microRNA (miRNA) sequencing was undertaken on natural killer (NK) cells collected from study participants.Samples from 88 children with viral bronchiolitis and 43 controls enrolled between 2009 and 2012 were analysed. Peripheral blood mononuclear cell (PBMC) IL-15 mRNA expression was significantly higher in those with moderate severity bronchiolitis compared with controls and those with severe disease. Serum IL-15 levels correlated with disease severity. The relative frequency of NK cells in peripheral blood was significantly reduced in participants with bronchiolitis. The NK cell miRNA transcriptome in bronchiolitis was distinct. Targets of de-regulated miRNA were differentially expressed in bronchiolitis, including JAK3, STAT5A and NFKB1 on the IL-15 signalling pathway.IL-15 is associated with disease severity in children hospitalised with viral bronchiolitis.

Characterising cytokine gene expression signatures in patients with severe sepsis.

INTRODUCTION: Severe sepsis in humans may be related to an underlying profound immune suppressive state. We investigated the link between gene expression of immune regulatory cytokines and the range of illness severity in patients with infection and severe sepsis. METHODS: A prospective observational study included 54 ICU patients with severe sepsis, 53 patients with infection without organ failure, and 20 healthy controls. Gene expression in peripheral blood mononuclear cells (PBMC) was measured using real-time polymerase chain reaction. RESULTS: Infection differed from health by decreased expression of the IL2, and IL23 and greater expression of IL10 and IL27. Severe sepsis differed from infection by having decreased IL7, IL23, IFN γ , and TNF α gene expression. An algorithm utilising mRNA copy number for TNF α , IFN γ , IL7, IL10, and IL23 accurately distinguished sepsis from severe sepsis with a receiver operator characteristic value of 0.88. Gene expression was similar with gram-positive and gram-negative infection and was similar following medical and surgical severe sepsis. Severity of organ failure was associated with serum IL6 protein levels but not with any index of cytokine gene expression in PBMCs. CONCLUSIONS: Immune regulatory cytokine gene expression in PBMC provides a robust method of modelling patients' response to infection.

Post-operative infection and sepsis in humans is associated with deficient gene expression of γc cytokines and their apoptosis mediators.

INTRODUCTION: Lymphocyte homeostasis is dependent on the γc cytokines. We hypothesised that sepsis in humans is associated with differential gene expression of the γc cytokines and their associated apoptosis mediators. METHODS: The study population consisted of a total of 60 patients with severe sepsis, 15 with gram negative bacteraemia, 10 healthy controls and 60 patients undergoing elective lung resection surgery. Pneumonia was diagnosed by CDC NNIC criteria. Gene expression in peripheral blood leukocytes (PBLs) of interleukin (IL)-2, 7, 15 and interferon (IFN)-γ, Bax, Bim, Bcl-2 was determined by qRT-PCR and IL-2 and IL-7 serum protein levels by ELISA. Gene expression of IL-2, 7 and IFN-γ was measured in peripheral blood leukocytes (PBL), cultured in the presence of lipopolysaccharide (LPS) and CD3 binding antibody (CD3ab) RESULTS: IL-2 gene expression was lower in the bacteraemia group compared with controls, and lower still in the sepsis group (P < 0.0001). IL-7 gene expression was similar in controls and bacteraemia, but lower in sepsis (P < 0.0001). IL-15 gene expression was similar in the three groups. Bcl-2 gene expression was less (P < 0.0001) and Bim gene expression was greater (P = 0.0003) in severe sepsis compared to bacteraemic and healthy controls. Bax gene expression was similar in the three groups.In lung resection surgery patients, post-operative pneumonia was associated with a perioperative decrease in IL-2 mRNA (P < 0.0001) and IL-7 mRNA (P = 0.003). IL-2 protein levels were reduced in sepsis and bacteraemia compared to controls (P = 0.02) but similar in pneumonia and non-pneumonia groups. IL-7 protein levels were similar in all groups.In cultured PBLs, IFN-γ gene expression was decreased in response to LPS and increased in response to CD3ab with sepsis: IL-7 gene expression increased in response to LPS in controls and to CD3ab with sepsis; Bcl-2 gene expression decreased in response to combined CD3ab and IL-2 with sepsis. CONCLUSIONS: Patients with infection and sepsis have deficient IL-2 and IL-7 gene expression in PBLs. Aberrant cytokine gene expression may precede the onset of infection.

The myeloid transcription factor KLF2 regulates the host response to polymicrobial infection and endotoxic shock.

Precise control of myeloid cell activation is required for optimal host defense. However, this activation process must be under exquisite control to prevent uncontrolled inflammation. Herein, we identify the Kruppel-like transcription factor 2 (KLF2) as a potent regulator of myeloid cell activation in vivo. Exposure of myeloid cells to hypoxia and/or bacterial products reduced KLF2 expression while inducing hypoxia inducible factor-1α (HIF-1α), findings that were recapitulated in human septic patients. Myeloid KLF2 was found to be a potent inhibitor of nuclear factor-kappaB (NF-κB)-dependent HIF-1α transcription and, consequently, a critical determinant of outcome in models of polymicrobial infection and endotoxemia. Collectively, these observations identify KLF2 as a tonic repressor of myeloid cell activation in vivo and an essential regulator of the innate immune system.

Transforming growth factor beta-1 and interleukin-17 gene transcription in peripheral blood mononuclear cells and the human response to infection.

INTRODUCTION: The occurrence of severe sepsis may be associated with deficient pro-inflammatory cytokine production. Transforming growth factor beta-1 (TGFbeta-1) predominantly inhibits inflammation and may simultaneously promote IL-17 production. Interleukin-17 (IL-17) is a recently described pro-inflammatory cytokine, which may be important in auto-immunity and infection. We investigated the hypothesis that the onset of sepsis is related to differential TGFbeta-1 and IL-17 gene expression. METHODS: A prospective observational study in a mixed intensive care unit (ICU) and hospital wards in a university hospital. Patients (59) with severe sepsis; 15 patients with gram-negative bacteraemia but without critical illness and 10 healthy controls were assayed for TGFbeta-1, IL-17a, IL-17f, IL-6 and IL-1beta mRNA in peripheral blood mononuclear cells (PBMC) by quantitative real-time PCR and serum protein levels by ELISA. RESULTS: TGFbeta-1 mRNA levels are reduced in patients with bacteraemia and sepsis compared with controls (p=0.02). IL-6 mRNA levels were reduced in bacteraemic patients compared with septic patients and controls (p=0.008). IL-1beta mRNA levels were similar in all groups, IL-17a and IL-17f mRNA levels are not detectable in peripheral blood mononuclear cells. IL-6 protein levels were greater in patients with sepsis than bacteraemic and control patients (p<0.0001). Activated TGFbeta-1 and IL-17 protein levels were similar in all groups. IL-1beta protein was not detectable in the majority of patients. CONCLUSIONS: Down regulation of TGFbeta-1 gene transcription was related to the occurrence of infection but not the onset of sepsis. Interleukin-17 production in PBMC may not be significant in the human host response to infection.