The safety of arterial hyperoxia is under increasing scrutiny. We performed a systematic review of the literature to determine whether any association exists between arterial hyperoxia and mortality ...in critically ill patient subsets.
Medline, Thomson Reuters Web of Science and Scopus databases were searched from inception to June 2014. Observational or interventional studies evaluating the relationship between hyperoxia (defined as a supranormal arterial O2 tension) and mortality in adult intensive care unit (ICU) patients were included. Studies primarily involving patients with exacerbations of chronic pulmonary disease, acute lung injury and perioperative administration were excluded. Adjusted odds ratio (OR) of patients exposed versus those not exposed to hyperoxia were extracted, if available. Alternatively, unadjusted outcome data were recorded. Data on patients, study characteristics and the criteria used for defining hyperoxia exposure were also extracted. Random-effects models were used for quantitative synthesis of the data, with a primary outcome of hospital mortality.
In total 17 studies (16 observational, 1 prospective before-after) were identified in different patient categories: mechanically ventilated ICU (number of studies (k) = 4, number of participants (n) = 189,143), post-cardiac arrest (k = 6, n = 19,144), stroke (k = 2, n = 5,537), and traumatic brain injury (k = 5, n = 7,488). Different criteria were used to define hyperoxia in terms of PaO2 value (first, highest, worst, mean), time of assessment and predetermined cutoffs. Data from studies on ICU patients were not pooled because of extreme heterogeneity (inconsistency (I(2)) 96.73%). Hyperoxia was associated with increased mortality in post-cardiac arrest patients (OR = 1.42 (1.04 to 1.92) I(2) 67.73%) stroke (OR = 1.23 (1.06 to 1.43) I(2) 0%) and traumatic brain injury (OR = 1.41 (1.03 to 1.94) I(2) 64.54%). However, these results are limited by significant heterogeneity between studies.
Hyperoxia may be associated with increased mortality in patients with stroke, traumatic brain injury and those resuscitated from cardiac arrest. However, these results are limited by the high heterogeneity of the included studies.
Glycocalyx degradation may contribute to microvascular dysfunction and tissue hypoperfusion during systemic inflammation and sepsis. In this observational study we evaluated the alteration of the ...sublingual microvascular glycocalyx in 16 healthy volunteers and 50 critically ill patients. Sidestream Dark Field images of the sublingual microcirculation were automatically analyzed by dedicated software. The Perfused Boundary Region (PBR) was calculated as the dimensions of the permeable part of the glycocalyx allowing the penetration of circulating red blood cells, providing an index of glycocalyx damage. The PBR was increased in ICU patients compared to healthy controls (2.7 2.59–2.88 vs. 2.46 2.37–2.59μm, p<0.0001) and tended to be higher in the 32 septic patients compared to non-septics (2.77 2.62–2.93 vs. 2.67 2.55–2.75μm, p=0.05), suggesting more severe glycocalyx alterations. A PBR of 2.76 showed the best discriminative ability towards the presence of sepsis (sensitivity: 50%, specificity: 83%; area under the receiver operating characteristic curve: 0.67, 95% CI 0.52–0.82, p=0.05). A weak positive correlation was found between PBR and heart rate (r=0.3, p=0.03). In 17 septic patients, a correlation was found between PBR and number of rolling leukocytes in post-capillary venules (RL/venule) (r=0.55, p=0.02), confirming that glycocalyx shedding enhances leukocyte–endothelium interaction.
•The endothelial glycocalyx is important for microvascular hemorheology.•The glycocalyx is altered in critically ill patients, especially during sepsis.•Loss of glycocalyx integrity may determine microcirculatory dysfunction and hypoperfusion.•Non-invasive monitoring of the glycocalyx might be helpful in the clinical practice.
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.
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.
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).
Old RBC transfusion was associated with an increase in plasma fHb in septic patients. Increasing plasma fHb levels were associated with decreased microvascular density.
ClinicalTrials.gov NCT01584999.
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).
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 (StO
) target) was applied daily until discharge from the ICU or death. A group of healthy volunteers were evaluated in a single session. During occlusion, StO
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 StO
) were calculated, reflecting microvascular reactivity. Outcomes were ICU and 90-day mortality.
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 StO
(7.9 (4.3, 12.6) versus 14.5 (11.2, 21.3), p = 0.001). Upslope and AUC StO
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 StO
≤ 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)).
In critically ill patients, NIRS with a VOT enables identification of alterations in tissue oxygen extraction capacity and microvascular reactivity that can predict mortality.
NCT02649088, www.clinicaltrials.gov , date of registration 23rd December 2015, retrospectively registered.
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
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.
In this prospective, observational study, 20 hemodynamically stable, mechanically ventilated patients with inspired oxygen concentration (FiO
) ≤0.5 and PaO
/FiO
≥ 200 mmHg underwent a 2-hour exposure to hyperoxia (FiO
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 FiO
(t2). The microvascular response to hyperoxia was assessed using sublingual sidestream dark field videomicroscopy and thenar near-infrared spectroscopy with a vascular occlusion test.
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 FiO
.
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.
ClinicalTrials.gov ( www.clinicaltrials.gov ), NCT02481843 , registered 15th June 2015, retrospectively registered.
This paper describes a new implementation of monolithic horizontal sensor, developed at the University of Salerno, based on the Folded Pendulum architecture, configurable both as seismometer and as ...accelerometer. The large low-frequency band (10-6 ÷ 10Hz), the high sensitivity ( in the band 0.1 ÷ 10 Hz) and the high quality factor in air (Q > 1500) are largely better than all the previous Folded Pendulum implementations. Moreover its monolithic implementation of the whole mechanics, coupled with a full tunability of its resonance frequency (70 mHz ÷ 1.2 Hz) obtained with a specially designed calibration procedure and with an integrated laser optical readout, guarantees both compactness, robustness and immunity to environmental noises. This makes this sensor suitable for a large number of scientific applications, also in high vacuum and cryogeny. Applications of this sensor are already started in the field of geophysics, including the study of seismic and newtonian noise for characterization of suitable sites for future underground interferometric detectors of gravitational waves.
Psoriasis is an inflammatory disease of the epidermis based on an immunological mechanism involving Langerhans cells and T lymphocytes that produce pro-inflammatory cytokines. Genetic factors, ...environmental factors, and improper nutrition are considered triggers of the disease. Numerous studies have reported that in a high number of patients, psoriasis is associated with obesity. Excess adipose tissue, typical of obesity, causes a systemic inflammatory status coming from the inflammatory active adipose tissue; therefore, weight reduction is a strategy to fight this pro-inflammatory state. This study aimed to evaluate how a nutritional regimen based on a ketogenic diet influenced the clinical parameters, metabolic profile, and inflammatory state of psoriasis patients. To this end, 30 psoriasis patients were subjected to a ketogenic nutritional regimen and monitored for 4 weeks by evaluating the clinical data, biochemical and clinical parameters, NMR metabolomic profile, and IL-2, IL-1β, TNF-α, IFN-γ, and IL-4 concentrations before and after the nutritional regimen. Our data show that a low-calorie ketogenic diet can be considered a successful strategy and therapeutic option to gain an improvement in psoriasis-related dysmetabolism, with significant correction of the full metabolic and inflammatory status.
The interaction between two-dimensional nanoflakes and bacteria in water-based physiological liquids is a hot topic that unveils new types of phenomena and is fundamental to bioscience applications. ...In this work, we extend Derjaguin, Landau, Verwey, and Overbeek theory (DLVO theory) that describes the properties of nano-objects in solutions, to the case of two-dimensional nanoflakes interacting with bacteria cell membranes, both for Gram-positive and Gram-negative bacteria. We have studied the role of the bacterial shape, membrane potential, and two-dimensional nanomaterials nature showing the interplay of these parameters in determining whether the interactions are attractive or repulsive and whether electrostatic or van der Waals forces are dominant. We calculated the interaction distances at equilibrium for different bacterial species and hydrophobic nanomaterials such as
in two environmentally friendly solvents, water and cyrene.
The idea of building a pipeline, on Egyptian territory, with the purpose of connecting the Red Sea to the Mediterranean Sea emerged before the 1967 War, which was responsible for the prolonged ...closure of the Suez Canal. The pipeline was inaugurated only in 1977 because of regional security issues. Despite the delay in its implementation, today the Sumed pipeline represents a strategic passage route which allows Middle Eastern oil to reach Western markets. L'idée de construire un oléoduc avec comme objectif de mettre en communication la Mer Rouge avec la Mer Méditerranée s'est développé avant la Guerre des six jours, laquelle a provoquée la fermeture prolongée du Canal de Suez. L'oléoduc a été inauguré seulement en 1977 à cause des problèmes liés à la sécurité régionale. Malgré le retard dans la mise en œuvre, aujourd'hui le Sumed représente une voie de passage stratégique du pétrole du Moyen-Orient.
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