Inferior vena cava distensibility during pressure support ventilation: a prospective study evaluating interchangeability of subcostal and trans­hepatic views, with both M­mode and automatic border tracing.

The Inferior Vena Cava (IVC) is commonly utilized to evaluate fluid status in the Intensive Care Unit (ICU),with more recent emphasis on the study of venous congestion. It is predominantly measured via subcostal approach (SC) or trans-hepatic (TH) views, and automated border tracking (ABT) software has been introduced to facilitate its assessment. Prospective observational study on patients ventilated in pressure support ventilation (PSV) with 2 × 2 factorial design. Primary outcome was to evaluate interchangeability of measurements of the IVC and the distensibility index (DI) obtained using both M-mode and ABT, across both SC and TH. Statistical analyses comprised Bland-Altman assessments for mean bias, limits of agreement (LoA), and the Spearman correlation coefficients. IVC visualization was 100% successful via SC, while TH view was unattainable in 17.4% of cases. As compared to the M-mode, the IVC-DI obtained through ABT approach showed divergences in both SC (mean bias 5.9%, LoA -18.4% to 30.2%, ICC = 0.52) and TH window (mean bias 6.2%, LoA -8.0% to 20.4%, ICC = 0.67). When comparing the IVC-DI measures obtained in the two anatomical sites, accuracy improved with a mean bias of 1.9% (M-mode) and 1.1% (ABT), but LoA remained wide (M-mode: -13.7% to 17.5%; AI: -19.6% to 21.9%). Correlation was generally suboptimal (r = 0.43 to 0.60). In PSV ventilated patients, we found that IVC-DI calculated with M-mode is not interchangeable with ABT measurements. Moreover, the IVC-DI gathered from SC or TH view produces not comparable results, mainly in terms of precision.

Estimation of the transpulmonary pressure from the central venous pressure in mechanically ventilated patients.

Transpulmonary pressure (PL) calculation requires esophageal pressure (PES) as a surrogate of pleural pressure (Ppl), but its calibration is a cumbersome technique. Central venous pressure (CVP) swings may reflect tidal variations in Ppl and could be used instead of PES, but the interpretation of CVP waveforms could be difficult due to superposition of heartbeat-induced pressure changes. Thus, we developed a digital filter able to remove the cardiac noise to obtain a filtered CVP (f-CVP). The aim of the study was to evaluate the accuracy of CVP and filtered CVP swings (ΔCVP and Δf-CVP, respectively) in estimating esophageal respiratory swings (ΔPES) and compare PL calculated with CVP, f-CVP and PES; then we tested the diagnostic accuracy of the f-CVP method to identify unsafe high PL levels, defined as PL>10 cmH2O. Twenty patients with acute respiratory failure (defined as PaO2/FiO2 ratio below 200 mmHg) treated with invasive mechanical ventilation and monitored with an esophageal balloon and central venous catheter were enrolled prospectively. For each patient a recording session at baseline was performed, repeated if a modification in ventilatory settings occurred. PES, CVP and airway pressure during an end-inspiratory and -expiratory pause were simultaneously recorded; CVP, f-CVP and PES waveforms were analyzed off-line and used to calculate transpulmonary pressure (PLCVP, PLf-CVP, PLPES, respectively). Δf-CVP correlated better than ΔCVP with ΔPES (r = 0.8, p = 0.001 vs. r = 0.08, p = 0.73), with a lower bias in Bland Altman analysis in favor of PLf-CVP (mean bias - 0.16, Limits of Agreement (LoA) -1.31, 0.98 cmH2O vs. mean bias - 0.79, LoA - 3.14, 1.55 cmH2O). Both PLf-CVP and PLCVP correlated well with PLPES (r = 0.98, p < 0.001 vs. r = 0.94, p < 0.001), again with a lower bias in Bland Altman analysis in favor of PLf-CVP (0.15, LoA - 0.95, 1.26 cmH2O vs. 0.80, LoA - 1.51, 3.12, cmH2O). PLf-CVP discriminated high PL value with an area under the receiver operating characteristic curve 0.99 (standard deviation, SD, 0.02) (AUC difference = 0.01 [-0.024; 0.05], p = 0.48). In mechanically ventilated patients with acute respiratory failure, the digital filtered CVP estimated ΔPES and PL obtained from digital filtered CVP represented a reliable value of standard PL measured with the esophageal method and could identify patients with non-protective ventilation settings.

Regional Cerebral Oxygen Saturation to Predict Favorable Outcome in Extracorporeal Cardiopulmonary Resuscitation: A Systematic Review and Meta-Analysis.

OBJECTIVE: This systematic review and meta-analysis aimed to investigate the role of regional cerebral oxygen saturation (rSO2) in predicting survival and neurologic outcomes after extracorporeal cardiopulmonary resuscitation (ECPR). DESIGN: The study authors performed a systematic review and meta-analysis of all available literature. SETTING: The authors searched relevant databases (Pubmed, Medline, Embase) for studies measuring precannulation rSO2 in patients undergoing ECPR and reporting mortality and/or neurologic outcomes. PARTICIPANTS: The authors included both in-hospital and out-of-hospital cardiac arrest patients receiving ECPR. They identified 3 observational studies, including 245 adult patients. INTERVENTIONS: The authors compared patients with a low precannulation rSO2 (≤15% or 16%) versus patients with a high (>15% or 16%) precannulation rSO2. In addition, the authors carried out subgroup analyses on out-of-hospital cardiac arrest (OHCA) patients. MEASUREMENTS AND MAIN RESULTS: A high precannulation rSO2 was associated with an overall reduced risk of mortality in ECPR recipients (98 out of 151 patients [64.9%] in the high rSO2 group, v 87 out of 94 patients [92.5%] in the low rSO2 group, risk differences [RD] -0.30; 95% CI -0.47 to -0.14), and in OHCA (78 out of 121 patients [64.5%] v 82 out of 89 patients [92.1%], RD 0.30; 95% CI -0.48 to -0.12). A high precannulation rSO2 also was associated with a significantly better neurologic outcome in the overall population (42 out of 151 patients [27.8%] v 2 out of 94 patients [2.12%], RD 0.22; 95% CI 0.13-0.31), and in OHCA patients (33 out of 121 patients [27.3%] v 2 out of 89 patients [2.25%] RD 0.21; 95% CI 0.11-0.30). CONCLUSIONS: A low rSO2 before starting ECPR could be a predictor of mortality and survival with poor neurologic outcomes.

Diaphragm ultrasound evaluation during weaning from mechanical ventilation in COVID-19 patients: a pragmatic, cross-section, multicenter study.

BACKGROUND: Diaphragmatic dysfunction is a major factor responsible for weaning failure in patients that underwent prolonged invasive mechanical ventilation for acute severe respiratory failure from COVID-19. This study hypothesizes that ultrasound measured diaphragmatic thickening fraction (DTF) could provide corroborating information for weaning COVID-19 patients from mechanical ventilation. METHODS: This was an observational, pragmatic, cross-section, multicenter study in 6 Italian intensive care units. DTF was assessed in COVID-19 patients undergoing weaning from mechanical ventilation from 1st March 2020 to 30th June 2021. Primary aim was to evaluate whether DTF is a predictive factor for weaning failure. RESULTS: Fifty-seven patients were enrolled, 25 patients failed spontaneous breathing trial (44%). Median length of invasive ventilation was 14 days (IQR 7-22). Median DTF within 24 h since the start of weaning was 28% (IQR 22-39%), RASS score (- 2 vs - 2; p = 0.031); Kelly-Matthay score (2 vs 1; p = 0.002); inspiratory oxygen fraction (0.45 vs 0.40; p = 0.033). PaO2/FiO2 ratio was lower (176 vs 241; p = 0.032) and length of intensive care stay was longer (27 vs 16.5 days; p = 0.025) in patients who failed weaning. The generalized linear regression model did not select any variables that could predict weaning failure. DTF was correlated with pH (RR 1.56 × 1027; p = 0.002); Kelly-Matthay score (RR 353; p < 0.001); RASS (RR 2.11; p = 0.003); PaO2/FiO2 ratio (RR 1.03; p = 0.05); SAPS2 (RR 0.71; p = 0.005); hospital and ICU length of stay (RR 1.22 and 0.79, respectively; p < 0.001 and p = 0.004). CONCLUSIONS: DTF in COVID-19 patients was not predictive of weaning failure from mechanical ventilation, and larger studies are needed to evaluate it in clinical practice further. Registered: ClinicalTrial.gov (NCT05019313, 24 August 2021).

Carotid Plaques From Symptomatic Patients Are Characterized by Local Increase in Xanthine Oxidase Expression.

Background and Purpose: XO (xanthine oxidase) is a key enzyme of uric acid metabolism and is thought to contribute to oxidative pathways that promote atherosclerotic plaque progression, yet its role in plaque destabilization is not well elucidated. We hypothesized that XO is expressed in carotid plaque from symptomatic patients in association with cardiovascular risk factors. Methods: Patients were stratified by symptoms, defined as presentation with an ipsilateral cerebral ischemic event. Carotid atherosclerotic plaques were obtained from 44 patients with symptomatic plaque and 44 patients without ischemic cerebral events. Protein expression of XO was evaluated by immunohistochemical staining and the percentage of cells expressing XO and CD68 (macrophage marker) compared between the groups. Biochemical and demographic cardiometabolic risk factors of study participants also were measured. Results: Carotid atherosclerotic plaques from symptomatic patients were associated with significantly higher XO expression versus asymptomatic plaque (median [interquartile range]: 1.24 [2.09] versus 0.16 [0.34]; P<0.001) and with significantly higher circulating uric acid levels (mean±SD: 7.36±2.10 versus 5.37±1.79 mg/dL; P<0.001, respectively). In addition, XO expression in atherosclerotic carotid plaque was inversely associated with serum high-density lipoproteins cholesterol levels (P=0.010, r=−0.30) and directly with circulating uric acid levels (P<0.001, r=0.45). The average percentage of macrophages that expressed XO was significantly higher in symptomatic versus asymptomatic plaques (median [interquartile range]: 93.37% [25] versus 46.15% [21], respectively; P<0.001). Conclusions: XO overexpression in macrophages is associated with increased serum uric acid and low high-density lipoproteins cholesterol levels and may potentially have a mechanistic role in carotid plaque destabilization. The current study supports a potential role for uric acid synthesis pathway as a target for management of carotid atherosclerosis in humans.

Antibody response to SARS-CoV-2 in infected patients with different clinical outcome.

Data regarding antibody responses to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in patients infected with COVID-19 are not yet available. In this study, we aimed to evaluate serum antibody responses in patients regardless of the outcome. We measured the circulating immunoglobulin G (IgG) antibody levels in 60 subjects with a certified history of SARS-CoV-2 infection by using immunoenzymatic, chemiluminescent, and Neutralization assays. Half patients had a severe infection, the other half were pauci-symptomatic. We analyzed their antibody response to see the trend of the humoral response. Our results showed a significant difference in circulating IgG level among the two groups. The neutralizing antibody response against SARS-CoV-2 was significantly higher among those who had severe disease. Furthermore, ten subjects from each group were screened twice, and a declining antibody trend was observed in pauci-symptomatic individuals. These findings provide evidence that humoral immunity against SARS-CoV-2 in pauci-symptomatic people is weak and may not be long-lasting. This may have implications for immunity strategy and prevention, since it is still not clear whether a time-dependent decrease of both circulating and neutralizing antibodies to nonprotective levels could occur in a longer time span and whether potential vaccines are able to induce a herd immunity and a durable response.

Pathway-specific reporter genes to study stem cell biology.

Little is known on the phenotypic characteristics of stem cells (SCs) after they are transplanted to the myocardium, in part due to lack of noninvasive platforms to study SCs directly in the living subject. Reporter gene imaging has played a valuable role in the noninvasive assessment of cell fate in vivo. In this study, we validated a pathway-specific reporter gene that can be used to noninvasively image the phenotype of SCs transplanted to the myocardium. Rat mesenchymal SCs (MSCs) were studied for phenotypic evidence of myogenic characteristics under in vitro conditions. After markers of myogenic characteristics were identified, we constructed a reporter gene sensor, comprising the firefly luciferase (Fluc) reporter gene driven by the troponin T (TnT) promoter (cardio MSCs had threefold expression in polymerase chain reaction compared to control MSCs) using a two-step signal amplification strategy. MSCs transfected with TnT-Fluc were studied and validated under in vitro conditions, showing a strong signal after MSCs acquired myogenic characteristics. Lastly, we observed that cardio MSCs had higher expression of the reporter sensor compared to control cells (0.005 ± 0.0005 vs 0.0025 ± 0.0008 Tnt-Fluc/ubiquitin-Fluc, P < .05), and that this novel sensor can detect the change in the phenotype of MSCs directly in the living subject. Pathway-specific reporter gene imaging allows assessment of changes in the phenotype of MSCs after delivery to the ischemic myocardium, providing important information on the phenotype of these cells. Imaging sensors like the one described here are critical to better understanding of the changes that SCs undergo after transplantation.

Hyperimmune plasma in three immuno-deficient patients affected by non-severe, prolonged COVID-19: a single-center experience.

BACKGROUND: Convalescent plasma (CP) and hyperimmune plasma (HP) are passive immunotherapies consisting in the infusion of plasma from recovered people into infected patients. Following pre-existing evidence in many other viral diseases, such as SARS, MERS and Ebola, CP and HP have also been proposed for the treatment of COVID-19. Nevertheless, due to the lack of large, well-designed, clinical trials, no clear-cut guidelines exist about what subtype of patient CP and HP should be administered to. CASE PRESENTATION: We have reported the cases of 3 patients, all immunosuppressed and affected by non-severe, prolonged COVID-19. They were treated with HP, whose neutralizing titer was higher than 1/80. The first patient was a 55-year-old male, who had undergone lung transplant. He was under therapy with Tacrolimus and developed non-neutralizing antibodies against SARS-CoV2. The second patient was a 77-year-old female, affected by follicular lymphoma. She had tested positive for SARS-CoV2 after 6 months. The third was a 60-year-old patient, affected by chronic leukemia. He did not develop antibodies after 2-month disease. All 3 patients received HP and had tested negative for SARS-CoV2 within 2 weeks. CONCLUSION: Despite encouraging initial data, no strong evidence exist in support of CP and HP to treat COVID-19. In our experience, although limited due to the reduced number of patients, we found a good safety and efficacy of HP in 3 immuno-deficient subjects. Further data are needed in order to assess whether this subtype of patients may particularly benefit from passive immunization.

Right Ventricular Dysfunction in Patients With COVID-19: A Systematic Review and Meta-analysis.

OBJECTIVE: This systematic review and meta-analysis aimed to describe the features of right ventricular impairment and pulmonary hypertension in coronavirus disease (COVID-19) and assess their effect on mortality. DESIGN: The authors carried out a systematic review and meta-analysis of observational studies. SETTING: The authors performed a search through PubMed, the International Clinical Trials Registry Platform, and the Cochrane Library for studies reporting right ventricular dysfunction in patients with COVID-19 and outcomes. PARTICIPANTS: The search yielded nine studies in which the appropriate data were available. INTERVENTIONS: Pooled odds ratios were calculated according to the random-effects model. MEASUREMENTS AND MAIN RESULTS: Overall, 1,450 patients were analyzed, and half of them were invasively ventilated. Primary outcome was mortality at the longest follow-up available. Mortality was 48.5% versus 24.7% in patients with or without right ventricular impairment (n = 7; OR = 3.10; 95% confidence interval [CI] 1.72-5.58; p = 0.0002), 56.3% versus 30.6% in patients with or without right ventricular dilatation (n = 6; OR = 2.43; 95% CI 1.41-4.18; p = 0.001), and 52.9% versus 14.8% in patients with or without pulmonary hypertension (n = 3; OR = 5.75; 95% CI 2.67-12.38; p < 0.001). CONCLUSION: Mortality in patients with COVID-19 requiring respiratory support and with a diagnosis of right ventricular dysfunction, dilatation, or pulmonary hypertension is high. Future studies should highlight the mechanisms of right ventricular derangement in COVID-19, and early detection of right ventricular impairment using ultrasound might be important to individualize therapies and improve outcomes.

COVID-19 and the burning issue of drug interaction: never forget the ECG.

The coronavirus disease of 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV2), has been rapidly escalating, becoming a relevant threat to global health. Being a recent virus outbreak, there are still no available therapeutic regimens that have been approved in large randomised trials and so patients are currently being treated with multiple drugs. This raises concerns regarding drug interaction and their implication in arrhythmic burden. In fact, two of the actually used drugs against SARS-CoV2, such as chloroquine and the combination lopinavir/ritonavir, might determine a QT (the time from the start of the Q wave to the end of the T wave) interval prolongation and they show several interactions with antiarrhythmic drugs and antipsychotic medications, making them prone to an increased risk of developing arrhythmias. This brief review focuses the attention on the most relevant drug interactions involving the currently used COVID-19 medications and their possible association with cardiac rhythm disorders, taking into account also pre-existing condition and precipitating factors that might additionally increase this risk. Furthermore, based on the available evidence and based on the knowledge of drug interaction, we propose a quick and simple algorithm that might help both cardiologists and non-cardiologists in the management of the arrhythmic risk before and during the treatment with the specific drugs used against SARS-CoV2.

COVID-19 in patients with heart failure: the new and the old epidemic.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has spread in nearly 200 countries in less than 4 months since its first identification; accordingly, the coronavirus disease 2019 (COVID 2019) has affirmed itself as a clinical challenge. The prevalence of pre-existing cardiovascular diseases in patients with COVID19 is high and this dreadful combination dictates poor prognosis along with the higher risk of intensive care mortality. In the setting of chronic heart failure, SARS-CoV-2 can be responsible for myocardial injury and acute decompensation through various mechanisms. Given the clinical and epidemiological complexity of COVID-19, patiens with heart failure may require particular care since the viral infection has been identified, considering an adequate re-evaluation of medical therapy and a careful monitoring during ventilation.

Serum KL-6 concentrations as a novel biomarker of severe COVID-19.

Severe acute respiratory syndrome coronavirus 2-induced direct cytopathic effects against type I and II pneumocytes mediate lung damage. Krebs von den Lungen-6 (KL-6) is mainly produced by damaged or regenerating alveolar type II pneumocytes. This preliminary study analyzed serum concentrations of KL-6 in patients with coronavirus disease (COVID-19) to verify its potential as a prognostic biomarker of severity. Twenty-two patients (median age [interquartile range] 63 [59-68] years, 16 males) with COVID-19 were enrolled prospectively. Patients were divided into mild-moderate and severe groups, according to respiratory impairment and clinical management. KL-6 serum concentrations and lymphocyte subset were obtained. Peripheral natural killer (NK) cells/µL were significantly higher in nonsevere patients than in the severe group (P = .0449) and the best cut-off value was 119 cells/µL. KL-6 serum concentrations were significantly higher in severe patients than the nonsevere group (P = .0118). Receiver operating characteristic analysis distinguished severe and nonsevere patients according to KL-6 serum levels and the best cut-off value was 406.5 U/mL. NK cell analysis and assay of KL-6 in serum can help identify severe COVID-19 patients. Increased KL-6 serum concentrations were observed in patients with severe pulmonary involvement, revealing a prognostic value and supporting the potential usefulness of KL-6 measurement to evaluate COVID-19 patients' prognosis.

Safe performance of echocardiography during the COVID-19 pandemic: a practical guide.

Coronavirus disease-2019 (COVID-19) outbreak has become a worldwide healthcare emergency, with continuously growing number of infected subjects. Considering the easy virus spread through respiratory droplets produced with cough, sneezes or spit or through close contact with infected people or surfaces, healthcare workers are further exposed to COVID-19. Particularly, echocardiography remains an essential diagnostic service which, due to the close contact with patients during the exam, provides echocardiographers high-risk of contagion. Therefore, the common modalities of performing echocardiography should be improved in this scenario, avoiding performing unnecessary exams, using the appropriate personal protective equipment depending on patients' status and location, optimizing time-effectiveness of the echocardiographic study and accurately sanitizing the environment and devices after each exam. This paper aims to provide a simple guide for the clinicians to balance between providing the best care to each patient and protecting themselves and other patients from the spread of the virus. It also proposes the use of the mnemonic PREVENT to resume the crucial indications to be followed for the execution of appropriate echocardiographic examination during the COVID-19 pandemic.

Electroencephalographic features in patients undergoing extracorporeal membrane oxygenation.

BACKGROUND: Neurologic injury is one of the most frequent causes of death in patients undergoing extracorporeal membrane oxygenation (ECMO). As neurological examination is often unreliable in sedated patients, additional neuromonitoring is needed. However, the value of electroencephalogram (EEG) in adult ECMO patients has not been well assessed. Therefore, the aim of this study was to assess the occurrence of electroencephalographic abnormalities in patients treated with extracorporeal membrane oxygenation (ECMO) and their association with 3-month neurologic outcome. METHODS: Retrospective analysis of all patients undergoing venous-venous (V-V) or venous-arterial (V-A) ECMO with a concomitant EEG recording (April 2009-December 2018), either recorded intermittently or continuously. EEG background was classified into four categories: mild/moderate encephalopathy (i.e., mostly defined by the presence of reactivity), severe encephalopathy (mostly defined by the absence of reactivity), burst-suppression (BS) and suppressed background. Epileptiform activity (i.e., ictal EEG pattern, sporadic epileptiform discharges or periodic discharges) and asymmetry were also reported. EEG findings were analyzed according to unfavorable neurological outcome (UO, defined as Glasgow Outcome Scale < 4) at 3 months after discharge. RESULTS: A total of 139 patients (54 [41-62] years; 60 (43%) male gender) out of 596 met the inclusion criteria and were analyzed. Veno-arterial (V-A) ECMO was used in 98 (71%); UO occurred in 99 (71%) patients. Continuous EEG was performed in 113 (81%) patients. The analysis of EEG background showed that 29 (21%) patients had severe encephalopathy, 4 (3%) had BS and 19 (14%) a suppressed background. In addition, 11 (8%) of patients had seizures or status epilepticus, 10 (7%) had generalized periodic discharges or lateralized periodic discharges, and 27 (19%) had asymmetry on EEG. In the multivariate analysis, the occurrence of ischemic stroke or intracranial hemorrhage (OR 4.57 [1.25-16.74]; p = 0.02) and a suppressed background (OR 10.08 [1.24-82.20]; p = 0.03) were independently associated with UO. After an adjustment for covariates, an increasing probability for UO was observed with more severe EEG background categories. CONCLUSIONS: In adult patients treated with ECMO, EEG can identify patients with a high likelihood of poor outcome. In particular, suppressed background was independently associated with unfavorable neurological outcome.

Usefulness of echocardiography to detect cardiac involvement in COVID-19 patients.

Coronavirus disease 2019 (COVID-19) outbreak is a current global healthcare burden, leading to the life-threatening severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, evidence showed that, even if the prevalence of COVID-19 damage consists in pulmonary lesions and symptoms, it could also affect other organs, such as heart, liver, and spleen. Particularly, some infected patients refer to the emergency department for cardiovascular symptoms, and around 10% of COVID-19 victims had finally developed heart injury. Therefore, the use of echocardiography, according to the safety local protocols and ensuring the use of personal protective equipment, could be useful firstly to discriminate between primary cardiac disease or COVID-19-related myocardial damage, and then for assessing and monitoring COVID-19 cardiovascular complications: acute myocarditis and arrhythmias, acute heart failure, sepsis-induced myocardial impairment, and right ventricular failure derived from treatment with high-pressure mechanical ventilation. The present review aims to enlighten the applications of transthoracic echocardiography for the diagnostic and therapeutic management of myocardial damage in COVID-19 patients.

Comparison of estimation of cardiac output using an uncalibrated pulse contour method and echocardiography during veno-venous extracorporeal membrane oxygenation.

INTRODUCTION: During veno-venous extracorporeal membrane oxygenation, cardiac output monitoring is essential to assess tissue oxygen delivery. Adequate arterial oxygenation depends on the ratio between the extracorporeal pump blood flow and the cardiac output. The aim of this study was to compare estimates of cardiac output and blood flow/cardiac output ratios made using an uncalibrated pulse contour method with those made using echocardiography in patients treated with veno-venous extracorporeal membrane oxygenation. METHODS: Cardiac output was estimated simultaneously using a pulse contour method (MostCareUp; Vygon, Encouen, France) and echocardiography in 17 hemodynamically stable patients treated with veno-venous extracorporeal membrane oxygenation. Comparisons were made using Bland-Altman and linear regression analysis. RESULTS: There were significant correlations between cardiac output estimated using pulse contour method and echocardiography and between blood flow/cardiac output estimated using pulse contour method and blood flow/cardiac output estimated using echocardiography (r = 0.84, p < 0.001 and r = 0.87, p < 0.001, respectively). Bland-Altman analysis showed a good agreement (bias -0.20 ± 0.50 L/min) and a low percentage of error (25%) for the cardiac output values estimated by the two methods. The bias between the blood flow/cardiac output ratios obtained with the two methods was 5.19% ± 12.3% (percentage of error = 28.1%). CONCLUSIONS: The pulse contour method is a valuable alternative to echocardiography for the assessment of cardiac output and the blood flow/cardiac output ratio in patients treated with veno-venous extracorporeal membrane oxygenation.

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.

Estimation of central arterial pressure from the radial artery in patients undergoing invasive neuroradiological procedures.

BACKGROUNDS: Central arterial pressure can be derived from analysis of the peripheral artery waveform. The aim of this study was to compare central arterial pressures measured from an intra-aortic catheter with peripheral radial arterial pressures and with central arterial pressures estimated from the peripheral pressure wave using a pressure recording analytical method (PRAM). METHODS: We studied 21 patients undergoing digital subtraction cerebral angiography under local or general anesthesia and equipped with a radial arterial catheter. A second catheter was placed in the ascending aorta for central pressure wave acquisition. Central (AO) and peripheral (RA) arterial waveforms were recorded simultaneously by PRAM for 90-180 s. During an off-line analysis, AO pressures were reconstructed (AOrec) from the RA trace using a mathematical model obtained by multi-linear regression analysis. The AOrec values obtained by PRAM were compared with the true central pressure value obtained from the catheter placed in the ascending aorta. RESULTS: Systolic, diastolic and mean pressures ranged from 79 to 180 mmHg, 47 to 102 mmHg, and 58 to 128 mmHg, respectively, for AO, and 83 to 174 mmHg, 47 to 107 mmHg, and 60 to 129 mmHg, respectively, for RA. The correlation coefficients between AO and RA were 0.86 (p < 0.01), 0.83 (p < 0.01) and 0.86 (p < 0.01) for systolic, diastolic and mean pressures, respectively, and the mean differences - 0.3 mmHg, 2.4 mmHg and 1.5 mmHg. The correlation coefficients between AO and AOrec were 0.92 (p < 0.001), 0.87 (p < 0.001) and 0.92 (p < 0.001), for systolic, diastolic and mean pressures, respectively, and the mean differences 0.01 mmHg, 1.8 mmHg and 1.2 mmHg. CONCLUSIONS: PRAM can provide reliable estimates of central arterial pressure.

The effects of blood transfusion on red blood cell distribution width in critically ill patients: a pilot study.

BACKGROUND: Red blood cell distribution width (RDW) is a measure of anisocytosis, generally used in the differential diagnosis of anemia. Recently, RDW was associated with increased mortality in critically ill patients. Red blood cell (RBC) transfusions are potential confounders on RDW values interpretation. The aim of this study was to analyze the changes in RDW after RBC transfusion in intensive care unit (ICU) patients. STUDY DESIGN AND METHODS: This was a prospective, observational study including patients admitted to ICU requiring 1 RBC unit. We analyzed RDW values of the patients at four study points: before RBC transfusion (T1), immediately after transfusion (T2), 24 hours after transfusion (T3), and 48 hours after transfusion (T4). We also collected laboratory data from donors and RBC units. Changes of RDW (ΔRDW) were computed as the difference between baseline RDW value and RDW at each time point after transfusion. RESULTS: We enrolled 36 patients. RDW values increased after transfusion (p < 0.001 at all points vs. baseline), with the highest level at T3. At T3, 34 of 36 patients (94%) had an abnormal RDW value (vs. 26/36, 72%) at baseline (p = 0.023). The maximum ΔRDW for each patient was moderately correlated with the difference between mean corpuscular volume (MCV)donors and MCVpatient (r = 0.478, p = 0.005). Subgroups analysis showed that the maximum ΔRDW was greater in patients with baseline MCV lower than 80 fL or higher than 100 fL (n = 7) or baseline RDW of more than 14.5% (n = 19). CONCLUSION: RBC transfusion significantly increased RDW values. This intervention should be accurately reported in the studies evaluating the prognostic role of RDW.

Cerebral Near-Infrared Spectroscopy in Adult Patients Undergoing Veno-Arterial Extracorporeal Membrane Oxygenation.

BACKGROUND: Acute cerebral complications (ACC) of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) are associated with poor long-term neurologic outcome. We described the role of rSO2 monitoring in detecting ACC and desaturations and their relationship with poor outcome when employing VA-ECMO. METHODS: Retrospective analysis of patients monitored by cerebral frontal near-infrared spectroscopy (NIRS) (CAS Medical Systems Inc., Branford, CT, USA) during VA-ECMO (November 2008-December 2015). ACC was defined as the presence of stroke and/or brain death, while cerebral desaturation as cortical oxygen tissue saturation (rSO2) < 60%. RESULTS: Fifty-six of 159 VA-ECMO patients (age 55 [36-60] years) were included; 18 (32%) developed ACC and 36 died (64%). Cerebral desaturation occurred in 43 (74%) patients, who had a higher mortality than those without cerebral desaturation (74 vs. 31%). A high sequential organ failure assessment (SOFA) score on the first day of ECMO (OR 1.40 [95% CIs 1.06-1.84]) and the minimum ECMO blood flow during the first 4 days of therapy (OR 3.05 [1.01-9.17]) were independently associated with the occurrence of cerebral desaturation. Cerebral desaturation occurred more frequently in patients with ACC than others (94 vs. 68%); patients with ACC also had a lower minimal rSO2 over time (49 vs. 54%) and more frequently had high right-left rSO2 differences (33 vs. 8%), which were both independent predictors of ACC. The occurrence of cerebral desaturation (OR 7.93 [1.62-38.74]) and high lactate concentrations during the first 4 days of ECMO support (OR 1.22 [1.03-1.46]) was independently associated with hospital mortality. CONCLUSIONS: Monitoring of rSO2 could be considered as an interesting tool to monitor the brain of patients on VA-ECMO.