Potential of acetaminophen on the sublingual microcirculation and peripheral tissue perfusion of febrile septic patients: prospective observational study

BACKGROUND

Acetaminophen (ACT) has been studied in septic patients with detectable plasmatic levels of cell-free hemoglobin (Hb), where it demonstrated to inhibit the hemoprotein-mediated lipid peroxidation and oxidative injury, with a potential of beneficial effect on the endothelium. On the basis of this background, the aim of this study was to evaluate the sublingual microcirculation and the peripheral tissue perfusion before-and-after administration of ACT on clinical judgment in a cohort of febrile septic and septic shock patients.

METHODS

Prospective observational study. 50 adult septic and septic shocks treated with ACT for pyrexia, where the sublingual microcirculation and the peripheral tissue perfusion with Near Infrared Spectroscopy (NIRS) and vascular occlusion test (VOT) were evaluated before ACT (t0), after 30 min (t1) and after 2 h (t2). Cell-free Hb and the markers of oxidative stress and endothelial damage were measured at t0 and t2.

RESULTS

The study showed a significant increase of the density of the perfused small and total vessels of the sublingual microcirculation 30 min after the infusion of ACT; it also showed an increase of the Microvascular Flow Index (MFI) and a decrease in the heterogeneity of the flow. At a peripheral muscular level, we found an acceleration in the reperfusion curve after VOT at t1, expression of a higher reactivity of the microvasculature.

CONCLUSIONS

ACT infusion did not show a clear correlation with cell-free Hb; however, it exhibited protective effect toward the microcirculation that was evident in particular in septic patients. This correlation merits further exploration.

Microcirculation-guided resuscitation in sepsis: the next frontier?

Microcirculatory dysfunction plays a key role in the pathogenesis of tissue dysoxia and organ failure in sepsis. Sublingual videomicroscopy techniques enable the real-time non-invasive assessment of microvascular blood flow. Alterations in sublingual microvascular perfusion were detected during sepsis and are associated with poor outcome. More importantly, sublingual videomicroscopy allowed to explore the effects of commonly applied resuscitative treatments in septic shock, such as fluids, vasopressors and inotropes, and showed that the optimization of macro-hemodynamic parameters may not be accompanied by an improvement in microvascular perfusion. This loss of "hemodynamic coherence," i.e., the concordance between the response of the macrocirculation and the microcirculation, advocates for the integration of microvascular monitoring in the management of septic patients. Nonetheless, important barriers remain for a widespread use of sublingual videomicroscopy in the clinical practice. In this review, we discuss the actual limitations of this technique and future developments that may allow an easier and faster evaluation of the microcirculation at the bedside, and propose a role for sublingual microvascular monitoring in guiding and titrating resuscitative therapies in sepsis.

Pharmacogenetics in critical care: association between CYP3A5 rs776746 A/G genotype and acetaminophen response in sepsis and septic shock

BACKGROUND

Pharmacogenetics could represent a further resource to understand the interindividual heterogeneity of response of the host to sepsis and to provide a personalized approach to the critical care patient.

METHODS

Secondary analysis of data from the prospective observational study NCT02750163, in 50 adult septic and septic shock patients treated with Acetaminophen (ACT) for pyrexia. We investigated the presence of two polymorphisms, located respectively in the genes UGT1A1 and CYP3A5, that encode for proteins related to the hepatic metabolism of ACT. The main dependent variables explored were plasmatic concentration of ACT, body temperature and hepatic parameters.

RESULTS

8% of the patients carried CYP3A5 rs776746 A/G genotypes and showed significantly higher plasma levels of ACT than GG wild type patients, and than patients with UGT1A1 rs8330 C/G genotypes.

CONCLUSIONS

Identifying specific genotypes of response to ACT may be helpful to guide a more personalized titration of therapy in sepsis and septic shock. CYP3A5 might be a good biomarker for ACT metabolism; however further studies are needed to confirm this result.

TRIAL REGISTRATION

NCT02750163.

Too much tolerance for hyperoxemia in mechanically ventilated patients with SARS-CoV-2 pneumonia? Report from an Italian intensive care unit

Background

In COVID-19 patients requiring mechanical ventilation, the administration of high oxygen (O2) doses for prolonged time periods may be necessary. Although life-saving in most cases, O2 may exert deleterious effects if administered in excessive concentrations. We aimed to describe the prevalence of hyperoxemia and excessive O2 administration in mechanically ventilated patients with SARS-CoV-2 pneumonia and determine whether hyperoxemia is associated with mortality in the Intensive Care Unit (ICU) or the onset of ventilator-associated pneumonia (VAP).

Materials and methods

Retrospective single-center study on adult patients with SARS-CoV-2 pneumonia requiring invasive mechanical ventilation for ≥48 h. Patients undergoing extracorporeal respiratory support were excluded. We calculated the excess O2 administered based on the ideal arterial O2 tension (PaO2) target of 55-80 mmHg. We defined hyperoxemia as PaO2 > 100 mmHg and hyperoxia + hyperoxemia as an inspired O2 fraction (FiO2) > 60% + PaO2 > 100 mmHg. Risk factors for ICU-mortality and VAP were assessed through multivariate analyses.

Results

One hundred thirty-four patients were included. For each day of mechanical ventilation, each patient received a median excess O2 of 1,121 [829-1,449] L. Hyperoxemia was found in 38 [27-55]% of arterial blood gases, hyperoxia + hyperoxemia in 11 [5-18]% of cases. The FiO2 was not reduced in 69 [62-76]% of cases of hyperoxemia. Adjustments were made more frequently with higher PaO2 or initial FiO2 levels. ICU-mortality was 32%. VAP was diagnosed in 48.5% of patients. Hyperoxemia (OR 1.300 95% CI [1.097-1.542]), time of exposure to hyperoxemia (OR 2.758 [1.406-5.411]), hyperoxia + hyperoxemia (OR 1.144 [1.008-1.298]), and daily excess O2 (OR 1.003 [1.001-1.005]) were associated with higher risk for ICU-mortality, independently of age, Sequential Organ failure Assessment score at ICU-admission and mean PaO2/FiO2. Hyperoxemia (OR 1.033 [1.006-1.061]), time of exposure to hyperoxemia (OR 1.108 [1.018-1.206]), hyperoxia + hyperoxemia (OR 1.038 [1.003-1.075]), and daily excess O2 (OR 1.001 [1.000-1.001]) were identified as risk factors for VAP, independently of body mass index, blood transfusions, days of neuromuscular blocking agents (before VAP), prolonged prone positioning and mean PaO2/FiO2 before VAP.

Conclusion

Excess O2 administration and hyperoxemia were common in mechanically ventilated patients with SARS-CoV-2 pneumonia. The exposure to hyperoxemia may be associated with ICU-mortality and greater risk for VAP.

Antibiotic Treatment of Acinetobacter baumannii Superinfection in Patients With SARS-CoV-2 Infection Admitted to Intensive Care Unit: An Observational Retrospective Study

Introduction

In COVID-19 patients on mechanical ventilation, VAP from Acinetobacter baumannii remains a crucial risk factor for death. Antibiotic resistance represents an important problem in treating this infection. This study aims to describe the evolution of the superinfection from PDR Acinetobacter baumannii in patients with acute respiratory failure from SARS-CoV-2 infection admitted to ICU and compare the impact of two different antibiotic strategies on microbiological negativization.

Methods

Single-center observational retrospective study, including patients admitted to our ICU from March 2020 to May 2021 for acute respiratory failure from SARS-CoV-2 infection who developed PDR Acinetobacter baumannii superinfection. Clinical data at ICU admission were collected, as well as the timing of isolation of Acinetobacter baumannii, its resistance profile, the site of infection, and the antibiotic therapy.

Results

Of the 32 patients enrolled, 10 patients (31.2%) were treated with the combination of high-dose ampicillin/sulbactam, high-dose tigecycline, intravenous and inhaled colistin (Protocol), the other 22 (68.8%) were treated with the combination of two antibiotics (Control). Of the 10 patients in the Protocol group, 8 patients (80%) received also fosfomycin. All patients (100%) in the Protocol group had microbiological negativization, while in the Control group microbiological negativization was observed in 8 (36.4%) patients, p < 0.01.

Conclusion

Our report shows microbiological negativization in all patients treated with the combination therapy of nebulized and intravenous colistin, high-dose tigecycline, and high-dose ampicillin/sulbactam. This combination of antibiotics seems to be a useful alternative when other treatments are not available or fail.

Microvascular dysfunction in pediatric patients with SARS-COV-2 pneumonia: Report of three severe cases

The coronavirus 19 (COVID-19) pandemic has affected hundreds of millions of people worldwide: in most of cases children and young people developed asymptomatic or pauci-symptomatic clinical pictures. However authors have showed that there are some categories of childhood more vulnerable to COVID-19 infection such as newborns or children with comorbidities. We report for the first time to the best of our knowledge about microvascular dysfunction in three pediatric clinical cases who developed COVID-19 infections with need of pediatric critical care. We found that sublingual microcirculation is altered in children with severe COVID-19 infection.

Our findings confirmed most of data already observed by other authors in adult population affected by severe COVID-19 infection, but with distinct characteristics than microcirculation alterations previous observed in a clinical case of MIS-C.

However we cannot establish direct correlation between microcirculation analysis and clinical or laboratory parameters in our series, by our experience we have found that sublingual microcirculation analysis allow clinicians to report directly about microcirculation dysfunction in COVID-19 patients and it could be a valuable bedside technique to monitor thrombosis complication in this population.

Mid-Regional Proadrenomedullin (MR-proADM) and Microcirculation in Monitoring Organ Dysfunction of Critical Care Patients With Infection: A Prospective Observational Pilot Study

Introduction: Microvascular alterations are involved in the development of organ injury in critical care patients. Mid-regional proadrenomedullin (MR-proADM) may predict organ damage and its evolution. The main objective of this study was to assess the correlation between MR-proADM and microvascular flow index (MFI) in a small cohort of 20 adult critical care patients diagnosed with infection, sepsis, or septic shock. Further objectives were to evaluate the correlation between the clearance of MR-proADM and the variables of microcirculation and between MR-proADM and the Sequential Organ Failure Assessment (SOFA) score.

Materials and Methods: This is a prospective observational pilot study. Inclusion criteria: consecutive adult patients admitted to intensive care unit (ICU) for or with infection-related illness. Daily measurement of MR-proADM and calculation of the SOFA score from admission in ICU to day 5. Repeated evaluations of sublingual microcirculation, collection of clinical data, and laboratory tests.

Results: Primary outcome: MR-proADM was not significantly correlated to the MFI at admission in ICU. A clearance of MR-proADM of 20% or more in the first 24 h was related to the improvement of the MFIs and MFIt [percentual variation of the MFIs + 12.35 (6.01–14.59)% vs. +2.23 (−4.45–6.01)%, p = 0.005; MFIt +9.09 (4.53–16.26)% vs. −1.43 (−4.36–3.12)%, p = 0.002].

Conclusion: This study did not support a direct correlation of MR-proADM with the MFI at admission in ICU; however, it showed a good correlation between the clearance of MR-proADM, MFI, and other microvascular variables. This study also supported the prognostic value of the marker. Adequately powered studies should be performed to confirm the findings.

Effects of Normoxia, Hyperoxia, and Mild Hypoxia on Macro-Hemodynamics and the Skeletal Muscle Microcirculation in Anesthetised Rats

Objectives: Excessive oxygen (O₂) administration may have a negative impact on tissue perfusion by inducing vasoconstriction and oxidative stress. We aimed to evaluate the effects of different inhaled oxygen fractions (FiO₂) on macro-hemodynamics and microvascular perfusion in a rat model.

Methods: Isoflurane-anesthetised spontaneously breathing male Wistar rats were equipped with arterial (carotid artery) and venous (jugular vein) catheters and tracheotomy, and randomized into three groups: normoxia (FiO₂ 21%, n = 6), hyperoxia (FiO₂ 100%, n = 6) and mild hypoxia (FiO₂ 15%, n = 6). Euvolemia was maintained by infusing Lactate Ringer solution at 10 ml/kg/h. At hourly intervals for 4 h we collected measurements of: mean arterial pressure (MAP); stroke volume index (SVI), heart rate (HR), respiratory rate (by means of echocardiography); arterial and venous blood gases; microvascular density, and flow quality (by means of sidestream dark field videomicroscopy on the hindlimb skeletal muscle).

Results: MAP and systemic vascular resistance index increased with hyperoxia and decreased with mild hypoxia (p < 0.001 in both cases, two-way analysis of variance). Hyperoxia induced a reduction in SVI, while this was increased in mild hypoxia (p = 0.002). The HR increased under hyperoxia (p < 0.05 vs. normoxia at 3 h). Cardiax index, as well as systemic O₂ delivery, did not significantly vary in the three groups (p = 0.546 and p = 0.691, respectively). At 4 h, microvascular vessel surface (i.e., the percentage of tissue surface occupied by vessels) decreased by 29 ± 4% in the hyperoxia group and increased by 19 ± 7 % in mild hypoxia group (p < 0.001). Total vessel density and perfused vessel density showed similar tendencies (p = 0.003 and p = 0.005, respectively). Parameters of flow quality (microvascular flow index, percentage of perfused vessels, and flow heterogeneity index) remained stable and similar in the three groups.

Conclusions: Hyperoxia induces vasoconstriction and reduction in skeletal muscle microvascular density, while mild hypoxia has an opposite effect.

Variation in the Outcome of Norepinephrine-Dependent Septic Patients After the Institution of a Patient-Tailored Therapy Protocol in an Italian Intensive Care Unit: Retrospective Observational Study

Objective: To evaluate the outcome of patients with septic shock after the institution of a patient tailored therapy protocol in our Intensive Care Unit (ICU).

Methods: Single-center retrospective observational study including 100 consecutive septic patients (≥ 16 years) requiring norepinephrine infusion, admitted to our ICU between 2018 and 2019 after the institution of a patient-tailored therapy protocol, compared with a historical control group of 100 patients admitted between 2010 and 2013 (historical controls). The patient-tailored therapy protocol included the use of IgM-enriched immunoglobulins for patients with low plasma IgM levels, blood purification strategies for patients with high plasma levels of cytokines or endotoxin, albumin correction and modulation of vasoactive agents. Clinical and therapeutic parameters were noted at the time of initiation of norepinephrine infusion and for the 1st 24 h. The primary outcome was ICU mortality.

Results: ICU-mortality was lower in the patient-tailored therapy cohort as compared to historical controls (32 vs. 57%, p < 0.001). Patient-tailored therapy was associated with a lower risk of ICU-mortality even after adjusting for the main clinical severity indices (adjusted odds ratio 0.331 [95% confidence interval 0.166–0.658], p = 0.002). After propensity score matching, 48 patients in historical control group and 48 patients in the patient-tailored therapy cohort with similar general characteristics were selected. ICU-mortality was lower in the patient-tailored therapy matched subgroup as compared to historical controls (40 vs. 60%, p = 0.037).

Conclusions: An individualized therapeutic approach in septic patients may be associated with a survival benefit. However, the use of an historical control group of patients admitted between 2010 and 2013 may introduce substantial bias. Further adequately designed studies are needed to demonstrate the impact of patient-tailored therapy on outcome.

Sublingual microcirculation in patients with SARS-CoV-2 undergoing veno-venous extracorporeal membrane oxygenation

Veno-Venous Extracorporeal Membrane Oxygenation (VV-ECMO) is a rescue treatment for severe acute respiratory failure refractory to conventional ventilation. We examined the alterations of sublingual microcirculation in patients with SARS-CoV-2 during VV-ECMO treatment and assessed the relationship between microvascular parameters and ventilation, hemodynamics, and laboratory tests.

Nine patients were included in the study and the following microcirculatory parameters were estimated: TVD 16.81 (14.46–18.6) mm/mm²; PVD 15.3 (14.09–17.96) mm/mm²; PPV 94.85% (93.82%–97.79%); MFI 2.5 (2.5–2.92); HI 0.4 (0.18–0.4). TVD and PVD were inversely related to D-dimer levels (rho = −0.667, p = 0.05 and rho = −0.733, p = 0.025 respectively), aspartate aminotransferase (AST) (rho = −0.886, p = 0.019 and rho = −0.886, p = 0.019 respectively) and alanine aminotransferase (ALT) (rho = −0.829, p = 0.042 and rho = −0.829, p = 0.042 respectively).

Our results showed an altered sublingual microcirculation in patients receiving VV-ECMO for severe SARS-CoV-2 and suggest a potential contribution of endothelia dysfunction to determine microvascular alteration.

Tissue oxygen saturation changes and postoperative complications in cardiac surgery: a prospective observational study

Background

Cardiac surgery with extracorporeal circulation (ECC) can induce microvascular dysfunction and tissue hypoperfusion. We hypothesized that the alterations in near-infrared spectroscopy (NIRS)-derived parameters would be associated with post-operative complications in cardiac surgery patients.

Methods

Prospective observational study performed at two University Hospitals. Ninety patients undergoing cardiac surgery with ECC were enrolled. The NIRS sensor was applied on the thenar eminence. A vascular occlusion test (VOT, 3-min ischemia) was performed at baseline (t0), at Intensive Care Unit (ICU) admission (t1), 3 (t2) and 6 (t3) hours later. Baseline tissue oxygen saturation (StO₂), oxygen extraction rate and microvascular reactivity indices were calculated.

Results

In the first hours after cardiac surgery, StO₂ tended to increase (86% [80–89] at T3 versus 82% [79–86] at T0, p = ns), while both tissue oxygen extraction and microvascular reactivity tended to decrease, as indicated by increasing occlusion slope (− 8.1%/min [− 11.2 to − 7] at T3 versus − 11.2%/min [− 13.9 to − 7.9] at T0, p = ns) and decreasing recovery slope (1.9%/sec [1.1–2.9] at T3 versus 3.1%/sec [2.3–3.9] at T0, p = ns). No substantial differences were found in NIRS-derived variables and their changes over time between patients with complications and those without complications.

Conclusions

Peripheral tissue oxygen extraction and microvascular reactivity were reduced during the first hours after cardiac surgery. NIRS-derived parameters were not able to predict complications in this population of cardiac surgery patients.

IgM-enriched immunoglobulins (Pentaglobin) may improve the microcirculation in sepsis: a pilot randomized trial

BACKGROUND

Polyclonal or IgM-enriched immunoglobulins may be beneficial during sepsis as an adjuvant immunomodulatory therapy. We aimed to test whether the infusion of IgM-enriched immunoglobulins improves microvascular perfusion during sepsis.

METHODS

Single-centre, randomized, double-blind, placebo-controlled phase II trial including adult patients with a diagnosis of sepsis or septic shock for less than 24 h. Patients received an intravenous infusion of 250 mg/kg (5 mL/kg) per day of IgM-enriched immunoglobulins (Pentaglobin, n = 10) for 72 h or placebo (NaCl 0.9%, n = 9). At baseline and after 24 and 72 h of infusion, the sublingual microcirculation was assessed with Incident Dark Field videomicroscopy. Thenar near-infrared spectroscopy (NIRS) was applied with a vascular occlusion test to assess tissue oxygenation and microvascular reactivity. Levels of interleukin (IL) 1-beta, IL-6, IL-8, IL-10 and tumour necrosis factor alpha were measured in the serum.

RESULTS

The perfused vessel density (PVD) for small vessels (diameter < 20 micron) increased in the Pentaglobin group (from 21.7 ± 4.7 to 25.5 ± 5.1 mm/mm²) and decreased in the placebo group (from 25 ± 5.8 to 20.7 ± 4.1 mm/mm², p for interaction < 0.001, two-way analysis of variance). The absolute between-group difference at 72 h was 4.77 (standard error 2.34), p = 0.140. The microvascular flow index for small vessels increased at 24 h in the Pentaglobin group (from 2.68 [2.38-2.78] to 2.93 [2.82-3], p < 0.01) and decreased at 72 h in the placebo group (from 2.83 [2.60-2.97] to 2.67 [2.48-2.73], p < 0.05). Changes in general parameters, cytokines and NIRS-derived parameters were similar between the two groups, except for IL-6 and IL-10 that significantly decreased at 72 h only in the Pentaglobin group.

CONCLUSIONS

A 72-h infusion of IgM-enriched immunoglobulins (Pentaglobin) in patients with sepsis or septic shock may be associated with an increase in sublingual microvascular perfusion. Further studies are needed to confirm our findings. Trial registration NCT02655133, www.ClinicalTrials.gov, date of registration 7th January 2016, https://www.clinicaltrials.gov/ct2/show/NCT02655133.

Changes in Cytokines, Haemodynamics and Microcirculation in Patients with Sepsis/Septic Shock Undergoing Continuous Renal Replacement Therapy and Blood Purification with CytoSorb

BACKGROUND

Extracorporeal blood purification therapies have been proposed as a strategy to remove inflammatory mediators during sepsis, thus improving outcome.

OBJECTIVES

We aimed to evaluate changes in cytokines, haemodynamics and microcirculation during blood purification with Cytosorb adsorber in septic patients.

METHODS

Prospective observational study on critically ill adult patients with sepsis/septic shock underwent renal replacement therapy (RRT) for acute renal failure and haemoadsorption with Cytosorb as adjunctive therapy for 24 h. Measurements were taken at baseline, after 6 and 24 h: haemodynamic parameters, arterial and central venous blood gases, plasma levels of tumour necrosis factor alpha, interleukin (IL) 1-beta, IL-6, IL-8 and IL-10. The sublingual microcirculation was assessed with sidestream dark field videomicroscopy to evaluate the perfused vessel density (PVD) and microvascular flow quality. Tissue oxygenation and microvascular reactivity were assessed with thenar near infrared spectroscopy (NIRS) with a vascular occlusion test.

RESULTS

Nine patients; plasma levels of IL-8 decreased at 24 h (p < 0.05 versus 6 h); no significant variation was found for other cytokines. Haemodynamic remained stable throughout the observation. Microvascular perfusion improved over time, with an increase in PVDs at 6 and 24 h (from 13.9 [13.3-16.4] to 15.7 [15-17.3] and 17 [14.8-18.6] mm/mm2 respectively, p = 0.003) and total vessel densities at 24 h (14.9 [13.9-16.9] vs. 17.9 [15.3-20], p = 0.0015). No significant variation was detected in NIRS-derived parameters. The Sequential Organ Failure Assessment score decreased from 12 ± 3 to 10 ± 1 at 24 h (p = 0.039).

CONCLUSIONS

In septic patients undergoing RRT, haemoadsorption with Cytosorb seems to determine a decreasing in plasma levels of IL-8, although levels of other cytokines did not vary significantly, and an improvement of microcirculation despite no significant variation in macro-haemodynamics.

Airway pressure release ventilation during acute hypoxemic respiratory failure: a systematic review and meta-analysis of randomized controlled trials

Background

Airway pressure release ventilation (APRV) has been considered a tempting mode of ventilation during acute respiratory failure within the concept of open lung ventilation. We performed a systematic review and meta-analysis to verify whether adult patients with hypoxemic respiratory failure have a higher number of ventilator-free days at day 28 when ventilated in APRV compared to conventional ventilation strategy. Secondary outcomes were difference in PaO₂/FiO₂ at day 3, ICU length of stay (LOS), ICU and hospital mortality, mean arterial pressure (MAP), risk of barotrauma and level of sedation. We searched MEDLINE, Scopus and Cochrane Central Register of Controlled Trials database until December 2018.

Results

We considered five RCTs for the analysis enrolling a total of 330 patients. For ventilatory-free day at day 28, the overall mean difference (MD) between APRV and conventional ventilation was 6.04 days (95%CI 2.12, 9.96, p = 0.003; I² = 65%, p = 0.02). Patients treated with APRV had a lower ICU LOS than patients treated with conventional ventilation (MD 3.94 days [95%CI 1.44, 6.45, p = 0.002; I² = 37%, p = 0.19]) and a lower hospital mortality (RD 0.16 [95%CI 0.02, 0.29, p = 0.03; I² = 0, p = 0.5]). PaO₂/FiO₂ at day 3 was not different between the two groups (MD 40.48 mmHg [95%CI − 25.78, 106.73, p = 0.23; I² = 92%, p < 0.001]). MAP was significantly higher during APRV (MD 5 mmHg [95%CI 1.43, 8.58, p = 0.006; I² = 0%, p = 0.92]). Then, there was no difference regarding the onset of pneumothorax under the two ventilation strategies (RR 1.94 [95%CI 0.54, 6.94, p = 0.31; I² = 0%, p = 0.74]). ICU mortality and sedation level were not included into quantitative analysis.

Conclusion

This study showed a higher number of ventilator-free days at 28 day and a lower hospital mortality in acute hypoxemic patients treated with APRV than conventional ventilation, without any negative hemodynamic impact or higher risk of barotrauma. However, these results need to be interpreted with caution because of the low-quality evidence supporting them and the moderate heterogeneity found. Other well-designed RCTs need to be conducted to confirm our findings.

Association between sublingual microcirculation, tissue perfusion and organ failure in major trauma: A subgroup analysis of a prospective observational study

INTRODUCTION

Previous studies described impaired microvascular perfusion and tissue oxygenation as reliable predictors of Multiple Organ Failure in major trauma. However, this relationship has been incompletely investigated. The objective of this analysis is to further evaluate the association between organ dysfunction and microcirculation after trauma.

MATERIALS AND METHODS

This is a retrospective subgroup analysis on 28 trauma patients enrolled for the Microcirculation DAIly MONitoring in critically ill patients study (NCT 02649088). Patients were divided in two groups according with their Sequential Organ Failure Assessment (SOFA) score at day 4. At admission and every 24 hours, the sublingual microcirculation was evaluated with Sidestream Darkfield Imaging (SDF) and peripheral tissue perfusion was assessed with Near Infrared Spectroscopy (NIRS) and Vascular Occlusion Test (VOT). Simultaneously, hemodynamic, clinical/laboratory parameters and main organ supports were collected.

RESULTS

Median SOFA score at Day 4 was 6.5. Accordingly, patients were divided in two groups: D4-SOFA ≤6.5 and D4-SOFA >6.5. The Length of Stay in Intensive Care was significantly higher in patients with D4-SOFA>6.5 compared to D4-SOFA≤6.5 (p = 0.013). Total Vessel Density of small vessels was significantly lower in patients with high D4-SOFA score at Day 1 (p = 0.002) and Day 2 (p = 0.006) after admission; the Perfused Vessel Density was lower in patients with high D4-SOFA score at Day 1 (p = 0.007) and Day 2 (p = 0.033). At Day 1, NIRS monitoring with VOT showed significantly faster tissue oxygen saturation downslope (p = 0.018) and slower upslope (p = 0.04) in patients with high D4-SOFA.

DISCUSSION

In our cohort of major traumas, sublingual microcirculation and peripheral microvascular reactivity were significantly more impaired early after trauma in those patients who developed more severe organ dysfunctions. Our data would support the hypothesis that restoration of macrocirculation can be dissociated from restoration of peripheral and tissue perfusion, and that microvascular alterations can be associated with organ failure.

Changes in the sublingual microcirculation following aortic surgery under balanced or total intravenous anaesthesia: a prospective observational study

Background

In vascular surgery with aortic cross-clamping, ischemia/reperfusion injury induces systemic haemodynamic and microcirculatory disturbances. Different anaesthetic regimens may have a varying impact on tissue perfusion. The aim of this study was to explore changes in microvascular perfusion in patients undergoing elective open abdominal aortic aneurysm repair under balanced or total intravenous anaesthesia.

Methods

Prospective observational study. Patients undergoing elective open infrarenal abdominal aortic aneurysm repair received balanced (desflurane + remifentanil, n = 20) or total intravenous anaesthesia (TIVA, propofol + remifentanil using target-controlled infusion, n = 20) according to the clinician’s decision. A goal-directed haemodynamic management was applied in all patients. Measurements were obtained before anaesthesia induction (baseline) and at end-surgery and included haemodynamics, arterial/venous blood gases, sublingual microvascular flow and density (incident dark field illumination imaging), peripheral muscle tissue oxygenation and microcirculatory reactivity (thenar near infrared spectroscopy with a vascular occlusion test).

Results

The two groups did not differ for baseline characteristics, mean aortic-clamping time and requirement of vasoactive agents during surgery. Changes in mean arterial pressure, systemic vascular resistance index, haemoglobin and blood lactate levels were similar between the two groups, while the cardiac index increased at end-surgery in patients undergoing balanced anaesthesia. The sublingual microcirculation was globally unaltered in the TIVA group at end-surgery, while patients undergoing balanced anaesthesia showed an increase in the total and perfused small vessel densities (from 16.6 ± 4.2 to 19.1 ± 5.4 mm/mm², p < 0.05). Changes in microvascular density were negatively correlated with changes in the systemic vascular resistance index. The area of reactive hyperaemia during the VOT increased in the balanced anaesthesia group (from 14.8 ± 8.1 to 25.6 ± 14.8%*min, p < 0.05). At end-surgery, the tissue haemoglobin index in the TIVA group was lower than that in the balanced anaesthesia group.

Conclusions

In patients undergoing elective open abdominal aortic aneurysm repair with a goal-directed hemodynamic management, indices of sublingual or peripheral microvascular perfusion/oxygenation were globally preserved with both balanced anaesthesia and TIVA. Patients undergoing balanced anaesthesia showed microvascular recruitment at end-surgery.

Trial registration

NCT03510793, https://www.clinicaltrials.gov, date of registration April 27th 2018, retrospectively registered.

MicroDAIMON study: Microcirculatory DAIly MONitoring in critically ill patients: a prospective observational study

Background

Until now, the prognostic value of microcirculatory alterations in critically ill patients has been mainly evaluated in highly selected subgroups. Aim of this study is to monitor the microcirculation daily in mixed group of Intensive Care Unit (ICU)-patients and to establish the association between (the evolution of) microcirculatory alterations and outcome.

Methods

This is a prospective longitudinal observational single-centre study in adult patients admitted to a 12-bed ICU in an Italian teaching hospital. Sublingual microcirculation was evaluated daily, from admission to discharge/death, using Sidestream Dark Field imaging. Videos were analysed offline to assess flow and density variables. Laboratory and clinical data were recorded simultaneously. A priori, a Microvascular Flow Index (MFI) < 2.6 was defined as abnormal. A binary logistic regression analysis was performed to evaluate the association between microcirculatory variables and outcomes; a Kaplan–Meier survival curve was built. Outcomes were ICU and 90-day mortality.

Results

A total of 97 patients were included. An abnormal MFI was present on day 1 in 20.6%, and in 55.7% of cases during ICU admission. Patients with a baseline MFI < 2.6 had higher ICU, in-hospital and 90-day mortality (45 vs. 15.6%, p = 0.012; 55 vs. 28.6%, p = 0.035; 55 vs. 26%, p = 0.017, respectively). An independent association between baseline MFI < 2.6 and outcome was confirmed in a binary logistic analysis (odds ratio 4.594 [1.340–15.754], p = 0.015). A heart rate (HR) ≥ 90 bpm was an adjunctive predictor of mortality. However, a model with stepwise inclusion of mean arterial pressure < 65 mmHg, HR ≥ 90 bpm, lactate > 2 mmol/L and MFI < 2.6 did not detect significant differences in ICU mortality. In case an abnormal MFI was present on day 1, ICU mortality was significantly higher in comparison with patients with an abnormal MFI after day 1 (38 vs. 6%, p = 0.001), indicating a time-dependent significant difference in prognostic value.

Conclusions

In a general ICU population, an abnormal microcirculation at baseline is an independent predictor for mortality. In this setting, additional routine daily microcirculatory monitoring did not reveal extra prognostic information. Further research is needed to integrate microcirculatory monitoring in a set of commonly available hemodynamic variables.

Trial registration NCT 02649088, www.clinicaltrials.gov. Date of registration: 23 December 2015, retrospectively registered

Electronic supplementary material

The online version of this article (10.1186/s13613-018-0411-9) contains supplementary material, which is available to authorized users.

Effects of short-term hyperoxia on erythropoietin levels and microcirculation in critically Ill patients: a prospective observational pilot study

Background

The normobaric oxygen paradox states that a short exposure to normobaric hyperoxia followed by rapid return to normoxia creates a condition of ‘relative hypoxia’ which stimulates erythropoietin (EPO) production. Alterations in glutathione and reactive oxygen species (ROS) may be involved in this process. We tested the effects of short-term hyperoxia on EPO levels and the microcirculation in critically ill patients.

Methods

In this prospective, observational study, 20 hemodynamically stable, mechanically ventilated patients with inspired oxygen concentration (FiO₂) ≤0.5 and PaO₂/FiO₂ ≥ 200 mmHg underwent a 2-hour exposure to hyperoxia (FiO₂ 1.0). A further 20 patients acted as controls. Serum EPO was measured at baseline, 24 h and 48 h. Serum glutathione (antioxidant) and ROS levels were assessed at baseline (t0), after 2 h of hyperoxia (t1) and 2 h after returning to their baseline FiO₂ (t2). The microvascular response to hyperoxia was assessed using sublingual sidestream dark field videomicroscopy and thenar near-infrared spectroscopy with a vascular occlusion test.

Results

EPO increased within 48 h in patients exposed to hyperoxia from 16.1 [7.4–20.2] to 22.9 [14.1–37.2] IU/L (p = 0.022). Serum ROS transiently increased at t1, and glutathione increased at t2. Early reductions in microvascular density and perfusion were seen during hyperoxia (perfused small vessel density: 85% [95% confidence interval 79–90] of baseline). The response after 2 h of hyperoxia exposure was heterogeneous. Microvascular perfusion/density normalized upon returning to baseline FiO₂.

Conclusions

A two-hour exposure to hyperoxia in critically ill patients was associated with a slight increase in EPO levels within 48 h. Adequately controlled studies are needed to confirm the effect of short-term hyperoxia on erythropoiesis.

Trial registration

ClinicalTrials.gov (www.clinicaltrials.gov), NCT02481843, registered 15th June 2015, retrospectively registered

Near-infrared spectroscopy for assessing tissue oxygenation and microvascular reactivity in critically ill patients: a prospective observational study

Background

Impaired microcirculatory perfusion and tissue oxygenation during critical illness are associated with adverse outcome. The aim of this study was to detect alterations in tissue oxygenation or microvascular reactivity and their ability to predict outcome in critically ill patients using thenar near-infrared spectroscopy (NIRS) with a vascular occlusion test (VOT).

Methods

Prospective observational study in critically ill adults admitted to a 12-bed intensive care unit (ICU) of a University Hospital. NIRS with a VOT (using a 40 % tissue oxygen saturation (StO₂) target) was applied daily until discharge from the ICU or death. A group of healthy volunteers were evaluated in a single session. During occlusion, StO₂ downslope was measured separately for the first (downslope 1) and last part (downslope 2) of the desaturation curve. The difference between downslope 2 and 1 was calculated (delta-downslope). The upslope and area of the hyperaemic phase (receive operating characteristic (ROC) area under the curve (AUC) of StO₂) were calculated, reflecting microvascular reactivity. Outcomes were ICU and 90-day mortality.

Results

Patients (n = 89) had altered downslopes and upslopes compared to healthy volunteers (n = 27). Mean delta-downslope was higher in ICU non-survivors (2.8 (0.4, 3.8) %/minute versus 0.4 (−0.8, 1.8) in survivors, p = 0.004) and discriminated 90-day mortality (ROC AUC 0.72 (95 % confidence interval 0.59, 0.84)). ICU non-survivors had lower mean upslope (141 (75, 193) %/minute versus 185 (143, 217) in survivors, p = 0.016) and AUC StO₂ (7.9 (4.3, 12.6) versus 14.5 (11.2, 21.3), p = 0.001). Upslope and AUC StO₂ on admission were significant although weak predictors of 90-day mortality (ROC AUC = 0.68 (0.54, 0.82) and 0.70 (0.58, 0.82), respectively). AUC StO₂ ≤ 6.65 (1st quartile) on admission was independently associated with higher 90-day mortality (hazard ratio 7.964 (95 % CI 2.211, 28.686)). The lowest upslope in the ICU was independently associated with survival after ICU discharge (odds ratio 0.970 (95 % CI 0.945, 0.996)).

Conclusions

In critically ill patients, NIRS with a VOT enables identification of alterations in tissue oxygen extraction capacity and microvascular reactivity that can predict mortality.

Trial registration

NCT02649088, www.clinicaltrials.gov, date of registration 23rd December 2015, retrospectively registered.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-016-1500-5) contains supplementary material, which is available to authorized users.

Plasma free hemoglobin and microcirculatory response to fresh or old blood transfusions in sepsis

BACKGROUND

Free hemoglobin (fHb) may induce vasoconstriction by scavenging nitric oxide. It may increase in older blood units due to storage lesions. This study evaluated whether old red blood cell transfusion increases plasma fHb in sepsis and how the microvascular response may be affected.

METHODS

This is a secondary analysis of a randomized study. Twenty adult septic patients received either fresh or old (<10 or >15 days storage, respectively) RBC transfusions. fHb was measured in RBC units and in the plasma before and 1 hour after transfusion. Simultaneously, the sublingual microcirculation was assessed with sidestream-dark field imaging. The perfused boundary region was calculated as an index of glycocalyx damage. Tissue oxygen saturation (StO2) and Hb index (THI) were measured with near-infrared spectroscopy and a vascular occlusion test was performed.

RESULTS

Similar fHb levels were found in the supernatant of fresh and old RBC units. Despite this, plasma fHb increased in the old RBC group after transfusion (from 0.125 [0.098-0.219] mg/mL to 0.238 [0.163-0.369] mg/mL, p = 0.006). The sublingual microcirculation was unaltered in both groups, while THI increased. The change in plasma fHb was inversely correlated with the changes in total vessel density (r = -0.57 [95% confidence interval -0.82, -0.16], p = 0.008), De Backer score (r = -0.63 [95% confidence interval -0.84, -0.25], p = 0.003) and THI (r = -0.72 [95% confidence interval -0.88, -0.39], p = 0.0003).

CONCLUSIONS

Old RBC transfusion was associated with an increase in plasma fHb in septic patients. Increasing plasma fHb levels were associated with decreased microvascular density.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01584999.

Glycaemic variability, infections and mortality in a medical-surgical intensive care unit

OBJECTIVE

In critically ill patients, glycaemic variability (GV) was reported as a better predictor of mortality than mean blood glucose level (BGL). We compared the ability of different GV indices and mean BGLs to predict mortality and intensive care unit-acquired infections in a population of ICU patients.

DESIGN, SETTING AND PARTICIPANTS

Retrospective study on adult ICU patients with ≥ three BGL measurements. GV was assessed by SD, coefficient of variation (CV) and mean amplitude of glycaemic excursion (MAGE), and by one timeweighted index, the glycaemic lability index (GLI), and compared with mean BGL. We studied 2782 patients admitted to the 12-bed medical-surgical ICU of a teaching hospital from January 2004 until December 2010.

MAIN OUTCOME MEASURES

Logistic regression analyses were performed to assess the association between GV and ICU mortality and ICU-acquired infections. The areas under receiver operating characteristic curves were calculated to compare the discriminatory ability of GV and mean BGL for infections and mortality.

RESULTS

Mortality was 16.6%, and 30% of patients had at least one infection. Patients with infections or diabetes or who were treated with insulin had a higher mean BGL and GV than other patients. GLI, SD, CV and MAGE were significantly associated with infections and mortality; mean BGL was not. Quartiles of increasing GLI were independently associated with higher mortality and an increased infection rate. Patients in the upper quartile of mean BGL and GLI had the strongest association with infections (odds ratio, 5.044 [95% CI, 1.695-15.007]; P = 0.004).

CONCLUSION

High GV is associated with higher risk of ICUCrit acquired infection and mortality.

Microcirculatory effects of the transfusion of leukodepleted or non-leukodepleted red blood cells in patients with sepsis: a pilot study

Introduction

Microvascular alterations impair tissue oxygenation during sepsis. A red blood cell (RBC) transfusion increases oxygen (O₂) delivery but rarely improves tissue O₂ uptake in patients with sepsis. Possible causes include RBC alterations due to prolonged storage or residual leukocyte-derived inflammatory mediators. The aim of this study was to compare the effects of two types of transfused RBCs on microcirculation in patients with sepsis.

Methods

In a prospective randomized trial, 20 patients with sepsis were divided into two separate groups and received either non-leukodepleted (n = 10) or leukodepleted (n = 10) RBC transfusions. Microvascular density and perfusion were assessed with sidestream dark field (SDF) imaging sublingually, before and 1 hour after transfusions. Thenar tissue O₂ saturation (StO₂) and tissue hemoglobin index (THI) were determined with near-infrared spectroscopy, and a vascular occlusion test was performed. The microcirculatory perfused boundary region was assessed in SDF images as an index of glycocalyx damage, and glycocalyx compounds (syndecan-1, hyaluronan, and heparan sulfate) were measured in the serum.

Results

No differences were observed in microvascular parameters at baseline and after transfusion between the groups, except for the proportion of perfused vessels (PPV) and blood flow velocity, which were higher after transfusion in the leukodepleted group. Microvascular flow index in small vessels (MFI) and blood flow velocity exhibited different responses to transfusion between the two groups (P = 0.03 and P = 0.04, respectively), with a positive effect of leukodepleted RBCs. When within-group changes were examined, microcirculatory improvement was observed only in patients who received leukodepleted RBC transfusion as suggested by the increase in De Backer score (P = 0.02), perfused vessel density (P = 0.04), PPV (P = 0.01), and MFI (P = 0.04). Blood flow velocity decreased in the non-leukodepleted group (P = 0.03). THI and StO₂ upslope increased in both groups. StO₂ and StO₂ downslope increased in patients who received non-leukodepleted RBC transfusions. Syndecan-1 increased after the transfusion of non-leukodepleted RBCs (P = 0.03).

Conclusions

This study does not show a clear superiority of leukodepleted over non-leukodepleted RBC transfusions on microvascular perfusion in patients with sepsis, although it suggests a more favorable effect of leukodepleted RBCs on microcirculatory convective flow. Further studies are needed to confirm these findings.

Trial registration

ClinicalTrials.gov, NCT01584999

Thermodilution vs pressure recording analytical method in hemodynamic stabilized patients

PURPOSE

Many mini-invasive devices to monitor cardiac output (CO) have been introduced and, among them, the pressure recording analytical method (PRAM). The aim of this study was to assess the agreement of PRAM with the intermittent transpulmonary thermodilution and continuous pulmonary thermodilution in measuring CO in hemodynamically stabilized patients.

MATERIALS AND METHODS

This is a prospective clinical study in a mixed medical-surgical intensive care unit (ICU) and in a postcardiac surgical ICU. Forty-eight patients were enrolled: 32 patients to the medical-surgical ICU monitored with PiCCO (Pulsion Medical System AG, Munich, Germany) and 16 were cardiac patients monitored with Vigilance (Edwards Lifesciences, Irvine, CA).

RESULTS

A total of 112 measurements were made. Ninety-six comparisons of paired CO measurements were made in patients hospitalized in medical-surgical ICU; 16, in cardiac surgical patients. The mean Vigilance-CO was 4.49 ± 0.99 L/min (range, 2.80-5.90 L/min), and the mean PRAM-CO was 4.27 ± 0.88 L/min (range, 2.85-6.19 L/min). The correlation coefficient between Vigilance-CO and PRAM-CO was 0.83 (95% confidence interval, 0.57-0.94; P < .001). The bias was 0.22 ± 0.55 L/min with limits of agreement between 0.87 and 1.30 L/min. The percentage error was 25%. Mean TP-CO was 6.78 ± 2.04 L/min (range, 4.12-11.27 L/min), and the mean PRAM-CO was 6.11 ± 2.18 L/min (range, 2.82-10.90 L/min). The correlation coefficient between PiCCO-CO and PRAM-CO was 0.91 (95% confidence interval, 0.83-0.96; P < .0001). The bias was 0.67 ± 0.89 L/min with limits of agreement -1.07 and 2.41 L/min. The coefficient of variation for PiCCO was 4% ± 2%, and the coefficient of variation for PRAM was 10% ± 8%. The percentage error was 28%.

CONCLUSIONS

The PRAM system showed good agreement with pulmonary artery catheter and PiCCO in hemodynamically stabilized patients.