The association between cerebral blood flow variations during on-pump coronary artery bypass grafting surgery and postoperative delirium.

INTRODUCTION: Postoperative delirium (POD) has a major impact on patient recovery after cardiac surgery. Although its pathophysiology remains unclear, there could be a correlation between cerebral blood flow (CBF) variations during cardio-pulmonary bypass (CPB) and POD. Our study aimed to evaluate whether variations in on-pump CBF, compared to pre-anesthesia and pre-CPB values, are associated with POD following coronary artery bypass grafting (CABG) surgery. METHODS: This prospective observational cohort study included 95 adult patients undergoing elective on-pump CABG surgery. Right middle cerebral artery blood flow velocity (MCAV) was assessed using Transcranial Doppler before anesthesia induction, before CPB and every fifteen minutes during CPB. Pre-anesthesia and pre-CPB values were chosen as baselines. Individual values, measured during CPB, were converted as percentage changes relative to these baselines and named as %MCAV0 and %MCAV1, respectively. POD was assessed using the Confusion Assessment Method for ICU (CAM-ICU) during the first 48 post-operative hours and with the 3-Minute Diagnostic Interview for Confusion Assessment Method (3D-CAM) on the fifth post-surgical day. RESULTS: Overall POD incidence was 17.9%. At 30 minutes of CPB, %MCAV0 was higher in POD group than in no-POD group (p = .05). %MCAV0 at 45 minutes of CPB was significantly higher in POD group (87 (±17) %) than in no-POD group (68 (±24) %), p = .04. %MCAV1 at 30 and 45 minutes of CPB were higher in POD group than in no-POD group, at the limit of statistical significance. We found %MCAV1 > 100% in POD group, but not in no-POD group. CONCLUSIONS: Significant differences in %MCAV0 became evident after 30 minutes of CPB, whereas differences in %MCAV1 at 45 minutes of CPB were at limit of statistical significance. In POD group %MCAV1 was higher than 100% at 30 and 45 minutes of CPB, which is supposed to be a sign of cerebral hyperperfusion. Monitoring CBF during CPB could have prognostic value for POD.

Shock index as predictor of massive transfusion and mortality in patients with trauma: a systematic review and meta-analysis.

BACKGROUND: Management of bleeding trauma patients is still a difficult challenge. Massive transfusion (MT) requires resources to ensure the safety and timely delivery of blood products. Early prediction of MT need may be useful to shorten the time process of blood product preparation. The primary aim of this study was to assess the accuracy of shock index to predict the need for MT in adult patients with trauma. For the same population, we also assessed the accuracy of SI to predict mortality. METHODS: This systematic review and meta-analysis was performed in accordance with the PRISMA guidelines. We performed a systematic search on MEDLINE, Scopus, and Web of Science from inception to March 2022. Studies were included if they reported MT or mortality with SI recorded at arrival in the field or the emergency department. The risk of bias was assessed using the QUADAS-2. RESULTS: Thirty-five studies were included in the systematic review and meta-analysis, for a total of 670,728 patients. For MT the overall sensibility was 0.68 [0.57; 0.76], the overall specificity was 0.84 [0.79; 0.88] and the AUC was 0.85 [0.81; 0.88]. Positive and Negative Likelihood Ratio (LR+; LR-) were 4.24 [3.18-5.65] and 0.39 [0.29-0.52], respectively. For mortality the overall sensibility was 0.358 [0.238; 0.498] the overall specificity 0.742 [0.656; 0.813] and the AUC 0.553 (confidence region for sensitivity given specificity: [0.4014; 0.6759]; confidence region for specificity given sensitivity: [0.4799; 0.6332]). LR+ and LR- were 1.39 [1.36-1.42] and 0.87 [0.85-0.89], respectively. CONCLUSIONS: Our study demonstrated that SI may have a limited role as the sole tool to predict the need for MT in adult trauma patients. SI is not accurate to predict mortality but may have a role to identify patients with a low risk of mortality.

Airway Ultrasound as Predictor of Difficult Direct Laryngoscopy: A Systematic Review and Meta-analysis.

BACKGROUND: Despite several clinical index tests that are currently applied for airway assessment, unpredicted difficult laryngoscopy may still represent a serious problem in anesthesia practice. The aim of this systematic review and meta-analysis was to evaluate whether preoperative airway ultrasound can predict difficult direct laryngoscopy in adult patients undergoing elective surgery under general anesthesia. METHODS: We searched the Medline, Scopus, and Web of Science databases from their inception to December 2020. The population of interest included adults who required tracheal intubation for elective surgery under general anesthesia without clear anatomical abnormalities suggesting difficult laryngoscopy. A bivariate model has been used to assess the accuracy of each ultrasound index test to predict difficult direct laryngoscopy. RESULTS: Fifteen studies have been considered for quantitative analysis of summary receiver operating characteristic (SROC). The sensitivity for distance from skin to epiglottis (DSE), distance from skin to hyoid bone (DSHB), and distance from skin to vocal cords (DSVC) was 0.82 (0.74-0.87), 0.71 (0.58-0.82), and 0.75 (0.62-0.84), respectively. The specificity for DSE, DSHB, and DSVC was 0.79 (0.70-0.87), 0.71 (0.57-0.82), and 0.72 (0.45-0.89), respectively. The area under the curve (AUC) for DSE, DSHB, DSVC, and ratio between the depth of the pre-epiglottic space and the distance from the epiglottis to the vocal cords (Pre-E/E-VC) was 0.87 (0.84-0.90), 0.77 (0.73-0.81), 0.78 (0.74-0.81), and 0.71 (0.67-0.75), respectively. Patients with difficult direct laryngoscopy have higher DSE, DSVC, and DSHB values than patients with easy laryngoscopy, with a mean difference of 0.38 cm (95% confidence interval [CI], 0.17-0.58 cm; P = .0004), 0.18 cm (95% CI, 0.01-0.35 cm; P = .04), and 0.23 cm (95% CI, 0.08-0.39 cm; P = .004), respectively. CONCLUSIONS: Our study demonstrates that airway ultrasound index tests are significantly different between patients with easy versus difficult direct laryngoscopy, and the DSE is the most studied index test in literature to predict difficult direct laryngoscopy. However, it is not currently possible to reach a definitive conclusion. Further studies are needed with better standardization of ultrasound assessment to limit all possible sources of heterogeneity.

Automated Algorithm Analysis of Sublingual Microcirculation in an International Multicentral Database Identifies Alterations Associated With Disease and Mechanism of Resuscitation.

OBJECTIVES: Reliable automated handheld vital microscopy image sequence analysis and the identification of disease states and effects of therapy are prerequisites for the routine use of quantitative sublingual microcirculation measurements at the point-of-care. The present study aimed to clinically validate the recently introduced MicroTools software in a large multicentral database of perioperative and critically ill patients and to use this automatic algorithm to data-mine and identify the sublingual microcirculatory variable changes in response to disease and therapy. DESIGN: Retrospective algorithm-based image analysis and data-mining within a large international database of sublingual capillary microscopy. Algorithm-based analysis was compared with manual analysis for validation. Thereafter, MicroTools was used to identify the functional microcirculatory alterations associated with disease conditions and identify therapeutic options for recruiting functional microcirculatory variables. SETTING: Ten perioperative/ICU/volunteer studies in six international teaching hospitals. PATIENTS: The database encompass 267 adult and pediatric patients undergoing surgery, treatment for sepsis, and heart failure in the ICU and healthy volunteers. INTERVENTIONS: Perioperative and ICU standard of care. MEASUREMENTS AND MAIN RESULTS: One thousand five hundred twenty-five handheld vital microscopy image sequences containing 149,257 microscopy images were analyzed. 3.89 × 10 RBC positions were tracked by the algorithm in real time, and offline manual analysis was performed. Good correlation and trending ability were found between manual and automatic total and functional capillary density (r = 0.6-0.8; p < 0.0001). RBC tracking within the database demonstrated changes in functional capillary density and/or RBC velocity in septic shock, heart failure, hypovolemia, obstructive shock, and hemodilution and thus detected the presence of a disease condition. Therapies recruiting the microcirculatory diffusion and convection capacity associated with systemic vasodilation and an increase in cardiac output were separately identified. CONCLUSIONS: Algorithm-based analysis of the sublingual microcirculation closely matched manual analysis across a broad spectrum of populations. It successfully identified a methodology to quantify microcirculatory alterations associated with disease and the success of capillary recruitment, improving point-of-care application of microcirculatory-targeted resuscitation procedures.

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.

SARS-CoV-2 infection in kidney transplant recipients: Experience of the italian marche region.

BACKGROUND: Infection related to Coronavirus-19 (CoV-2) is pandemic affecting more than 4 million people in 187 countries worldwide. By May 10, 2020, it caused more than 280 000 deaths all over the world. Preliminary data reported a high prevalence of CoV-2 infection and mortality due to severe acute respiratory syndrome related CoV-2 (SARS-CoV-2) in kidney-transplanted patients (KTRs). Nevertheless, the outcomes and the best treatments for SARS-CoV-2-affected KTRs remain unclear. METHODS: In this report, we describe the clinical data, the treatments, and the outcomes of 5 KTRs with SARS-CoV-2 admitted to our hospital in Ancona, Marche region, Italy, from March 17 to present. Due to the severity of SARS-CoV-2, immunosuppression with calcineurin inhibitors, antimetabolites, and mTOR-inhibitors were stopped at the admission. All KTRs were treated with low-dose steroids. 4/5 KTRs were treated with hydroxychloroquine. All KTRs received tocilizumab up to one dose. RESULTS: Overall, the incidence of SARS-CoV-2 in KTRs in the Marche region was 0.85%. 3/5 were admitted in ICU and intubated. One developed AKI with the need of CRRT with Cytosorb. At present, two patients died, two patients were discharged, and one is still inpatient in ICU. CONCLUSIONS: The critical evaluation of all cases suggests that the timing of the administration of tocilizumab, an interleukin-6 receptor antagonist, could be associated with a better efficacy when administered in concomitance to the drop of the oxygen saturation. Thus, in SARS-CoV-2-affected KTRs, a close biochemical and clinical monitoring should be set up to allow physicians to hit the virus in the right moment such as a sudden reduction of the oxygen saturation and/or a significant increase in the laboratory values such as D-dimer.

Procedural sedation for direct current cardioversion: a feasibility study between two management strategies in the emergency department.

BACKGROUND: A cardiologist-only approach to procedural sedation with midazolam in the setting of elective cardioversion (DCC) for AF has already been proven as safe as sedation with propofol and anaesthesiologist assistance. No data exist regarding the safety of such a strategy during emergency procedures. The aim of this study is to compare the feasibility of sedation with midazolam, administered by a cardiologist, to an anaesthesiologist-assisted protocol with propofol in emergency DCC. METHODS: Single centre, prospective, open blinded, randomized study including all consecutive patients admitted to the Emergency Department requiring urgent or emergency DCC. Patients were randomized in a 1:1 fashion to either propofol or midazolam treatment arm. Patients in the midazolam group were managed by the cardiologist only, while patients treated with propofol group underwent DCC with anaesthesiologist assistance. RESULTS: Sixty-nine patients were enrolled and split into two groups. Eighteen patients (26.1%) experienced peri-procedural adverse events (bradycardia, severe hypotension and severe hypoxia), which were similar between the two groups and all successfully managed by the cardiologist. No deaths, stroke or need for invasive ventilation were registered. Patients treated with propofol experienced a greater decrease in systolic and diastolic blood pressure when compared with those treated with midazolam. As the procedure was shorter when midazolam was used, the median cost of urgent/emergency DCC with midazolam was estimated to be 129.0 € (1st-3rd quartiles 114.6-151.6) and 195.6 € (1st-3rd quartiles 147.3-726.7) with propofol (p < .001). CONCLUSIONS: Procedural sedation with midazolam given by the cardiologist alone was feasible, well-tolerated and cost-effective in emergency DCC.

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.

Estimated oxygen extraction versus dynamic parameters of fluid-responsiveness for perioperative hemodynamic optimization of patients undergoing non-cardiac surgery: a non-inferiority randomized controlled trial.

BACKGROUND: Goal directed therapy (GDT) is able to improve mortality and reduce complications in selected high-risk patients undergoing major surgery. The aim of this study is to compare two different strategies of perioperative hemodynamic optimization: one based on optimization of preload using dynamic parameters of fluid-responsiveness and the other one based on estimated oxygen extraction rate (O2ER) as target of hemodynamic manipulation. METHODS: This is a multicenter randomized controlled trial. Adult patients undergoing elective major open abdominal surgery will be allocated to receive a protocol based on dynamic parameters of fluid-responsiveness or a protocol based on estimated O2ER. The hemodynamic optimization will be continued for 6 h postoperatively. The primary outcome is difference in overall postoperative complications rate between the two protocol groups. Fluids administered, fluid balance, utilization of vasoactive drugs, hospital length of stay and mortality at 28 day will also be assessed. DISCUSSION: As a predefined target of cardiac output (CO) or oxygen delivery (DO2) seems to be not adequate for every patient, a personalized therapy is likely more appropriate. Following this concept, dynamic parameters of fluid-responsiveness allow to titrate fluid administration aiming CO increase but avoiding fluid overload. This approach has the advantage of personalized fluid therapy, but it does not consider if CO is adequate or not. A protocol based on O2ER considers this second important aspect. Although positive effects of perioperative GDT have been clearly demonstrated, currently studies comparing different strategies of hemodynamic optimization are lacking. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04053595. Registered on 12/08/2019.

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.

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.

Evaluation of two neck ultrasound measurements as predictors of difficult direct laryngoscopy: A prospective observational study.

BACKGROUND: Unpredictable difficult laryngoscopy remains a challenge for anaesthesiologists, especially if difficult ventilation occurs during standard laryngoscopy. Accurate airway assessment should always be performed, but the common clinical screening tests have shown low sensitivity and specificity with a limited predictive value. Ultrasound-based airway assessment has been proposed recently as a useful, simple, noninvasive bedside tool as an adjunct to clinical methods, but to date, few studies are available about the potential role of ultrasound in difficult airway evaluation, and these are mostly limited to specific groups of patients. OBJECTIVES: The aim of this study was to determine the correlation between the sonographic measurements of anterior cervical soft tissues thickness and Cormack-Lehane grade view at direct laryngoscopy in patients with normal clinical screening tests. DESIGN: Prospective, single blinded, observational study. SETTING: Operating theatre of a teaching hospital from May 2017 to September 2017. PATIENTS: A total of 301 patients at least 18 years of age undergoing elective surgery under general anaesthesia with tracheal intubation were included in the study. OUTCOME MEASURES: Pre-operative evaluation was performed before surgery, demographic variables were collected and clinical screening tests to predict a difficult airway were performed. Patients with predicted difficult intubation were excluded. A 10 to 13-MHz linear ultrasound transducer was placed in the transverse plane and the thickness of the anterior cervical soft tissues was measured at two levels [thyrohyoid membrane (pre-epiglottic space) and vocal cords (laryngeal inlet)] with the patient's head in a neutral position. At each level, the distance from the skin in the median axis and the surrounding area was measured. The laryngoscopic view was graded by a different anaesthetist with more than 5 years of experience with direct laryngoscopy, blinded to the ultrasound assessments. RESULTS: The 'pre-epiglottic space thickness' at the level of thyrohyoid membrane was measured as the median distance from skin to epiglottis (mDSE) and the pre-epiglottic area was calculated; the mDSE cut-off value of 2.54 cm (sensitivity 82%, specificity 91%) and the pre-epiglottic area cut-off value of 5.04 cm (sensitivity 85%, specificity 88%) were the best predictors of a Cormack-Lehane grade at least 2b at direct laryngoscopy and of difficult intubation. The cut-off value of mDSE showed greater sensitivity in female patients (94 vs. 86%) and greater specificity in male patients (92 vs. 83%). No correlation was found between difficult laryngoscopy and ultrasound assessments at the level of the vocal cords. CONCLUSION: Airways ultrasounds might be considered as a predictor of restricted/difficult laryngoscopy and unpredicted difficult intubation. TRIAL REGISTRATION: ClinicalTrials.gov: NCT03547193.

Oxygen in the critically ill: friend or foe?

PURPOSE OF REVIEW: To examine the potential harmful effects of hyperoxia and summarize the results of most recent clinical studies evaluating oxygen therapy in critically ill patients. RECENT FINDINGS: Excessive oxygen supplementation may have detrimental pulmonary and systemic effects because of enhanced oxidative stress and inflammation. Hyperoxia-induced lung injury includes altered surfactant protein composition, reduced mucociliary clearance and histological damage, resulting in atelectasis, reduced lung compliance and increased risk of infections. Hyperoxemia causes vasoconstriction, reduction in coronary blood flow and cardiac output and may alter microvascular perfusion. Observational studies showed a close relationship between hyperoxemia and increased mortality in several subsets of critically ill patients. In absence of hypoxemia, the routine use of oxygen therapy in patients with myocardial infarction, stroke, traumatic brain injury, cardiac arrest and sepsis, showed no benefit but rather it seems to be harmful. In patients admitted to intensive care unit, a conservative oxygen therapy aimed to maintain arterial oxygenation within physiological range has been proved to be well tolerated and may improve outcome. SUMMARY: Liberal O2 use and unnecessary hyperoxia may be detrimental in critically ill patients. The current evidence supports the use of a conservative strategy in O2 therapy to avoid patient exposure to unnecessary hyperoxemia.

Mildly elevated lactate levels are associated with microcirculatory flow abnormalities and increased mortality: a microSOAP post hoc analysis.

BACKGROUND: Mildly elevated lactate levels (i.e., 1-2 mmol/L) are increasingly recognized as a prognostic finding in critically ill patients. One of several possible underlying mechanisms, microcirculatory dysfunction, can be assessed at the bedside using sublingual direct in vivo microscopy. We aimed to evaluate the association between relative hyperlactatemia, microcirculatory flow, and outcome. METHODS: This study was a predefined subanalysis of a multicenter international point prevalence study on microcirculatory flow abnormalities, the Microcirculatory Shock Occurrence in Acutely ill Patients (microSOAP). Microcirculatory flow abnormalities were assessed with sidestream dark-field imaging. Abnormal microcirculatory flow was defined as a microvascular flow index (MFI) < 2.6. MFI is a semiquantitative score ranging from 0 (no flow) to 3 (continuous flow). Associations between microcirculatory flow abnormalities, single-spot lactate measurements, and outcome were analyzed. RESULTS: In 338 of 501 patients, lactate levels were available. For this substudy, all 257 patients with lactate levels ≤ 2 mmol/L (median [IQR] 1.04 [0.80-1.40] mmol/L) were included. Crude ICU mortality increased with each lactate quartile. In a multivariable analysis, a lactate level > 1.5 mmol/L was independently associated with a MFI < 2.6 (OR 2.5, 95% CI 1.1-5.7, P = 0.027). CONCLUSIONS: In a heterogeneous ICU population, a single-spot mildly elevated lactate level (even within the reference range) was independently associated with increased mortality and microvascular flow abnormalities. In vivo microscopy of the microcirculation may be helpful in discriminating between flow- and non-flow-related causes of mildly elevated lactate levels. TRIAL REGISTRATION: ClinicalTrials.gov, NCT01179243 . Registered on August 3, 2010.

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.

Ability and efficiency of an automatic analysis software to measure microvascular parameters.

Analysis of the microcirculation is currently performed offline, is time consuming and operator dependent. The aim of this study was to assess the ability and efficiency of the automatic analysis software CytoCamTools 1.7.12 (CC) to measure microvascular parameters in comparison with Automated Vascular Analysis (AVA) software 3.2. 22 patients admitted to the cardiothoracic intensive care unit following cardiac surgery were prospectively enrolled. Sublingual microcirculatory videos were analysed using AVA and CC software. The total vessel density (TVD) for small vessels, perfused vessel density (PVD) and proportion of perfused vessels (PPV) were calculated. Blood flow was assessed using the microvascular flow index (MFI) for AVA software and the averaged perfused speed indicator (APSI) for the CC software. The duration of the analysis was also recorded. Eighty-four videos from 22 patients were analysed. The bias between TVD-CC and TVD-AVA was 2.20 mm/mm2 (95 % CI 1.37-3.03) with limits of agreement (LOA) of -4.39 (95 % CI -5.66 to -3.16) and 8.79 (95 % CI 7.50-10.01) mm/mm2. The percentage error (PE) for TVD was ±32.2 %. TVD was positively correlated between CC and AVA (r = 0.74, p < 0.001). The bias between PVD-CC and PVD-AVA was 6.54 mm/mm2 (95 % CI 5.60-7.48) with LOA of -4.25 (95 % CI -8.48 to -0.02) and 17.34 (95 % CI 13.11-21.57) mm/mm2. The PE for PVD was ±61.2 %. PVD was positively correlated between CC and AVA (r = 0.66, p < 0.001). The median PPV-AVA was significantly higher than the median PPV-CC [97.39 % (95.25, 100 %) vs. 81.65 % (61.97, 88.99), p < 0.0001]. MFI categories cannot estimate or predict APSI values (p = 0.45). The time required for the analysis was shorter with CC than with AVA system [2'42″ (2'12″, 3'31″) vs. 16'12″ (13'38″, 17'57″), p < 0.001]. TVD is comparable between the two softwares, although faster with CC software. The values for PVD and PPV are not interchangeable given the different approach to assess microcirculatory flow.

Impact of microcirculatory video quality on the evaluation of sublingual microcirculation in critically ill patients.

We aimed to assess the impact of image quality on microcirculatory evaluation with sidestream dark-field (SDF) videomicroscopy in critically ill patients and explore factors associated with low video quality. This was a retrospective analysis of a single-centre prospective observational study. Videos of the sublingual microcirculation were recorded using SDF videomicroscopy in 100 adult patients within 12 h from admittance to the intensive care unit and every 24 h until discharge/death. Parameters of vessel density and perfusion were calculated offline for small vessels. For all videos, a quality score (-12 = unacceptable, 1 = suboptimal, 2 = optimal) was assigned for brightness, focus, content, stability, pressure and duration. Videos with a total score ≤8 were deemed as unacceptable. A total of 2455 videos (853 triplets) was analysed. Quality was acceptable in 56 % of videos. Lower quality was associated with worse microvascular density and perfusion. Unreliable triplets (≥1 unacceptable or missing video, 65 % of total) showed lower vessel density, worse perfusion and higher flow heterogeneity as compared to reliable triplets (p < 0.001). Quality was higher among triplets collected by an extensively-experienced investigator or in patients receiving sedation or mechanical ventilation. Perfused vessel density was higher in patients with Glasgow Coma Scale (GCS) ≤8 (18.9 ± 4.5 vs. 17.0 ± 3.9 mm/mm2 in those with GCS >8, p < 0.001) or requiring mechanical ventilation (18.0 ± 4.5 vs. 17.2 ± 3.8 mm/mm2 in not mechanically ventilated patients, p = 0.059). We concluded that SDF video quality depends on both the operator's experience and patient's cooperation. Low-quality videos may produce spurious data, leading to an overestimation of microvascular alterations.

Comparison Between Doppler-Echocardiography and Uncalibrated Pulse Contour Method for Cardiac Output Measurement: A Multicenter Observational Study.

OBJECTIVES: Echocardiography and pulse contour methods allow, respectively, noninvasive and less invasive cardiac output estimation. The aim of the present study was to compare Doppler echocardiography with the pulse contour method MostCare for cardiac output estimation in a large and nonselected critically ill population. DESIGN: A prospective multicenter observational comparison study. SETTING: The study was conducted in 15 European medicosurgical ICUs. PATIENTS: We assessed cardiac output in 400 patients in whom an echocardiographic evaluation was performed as a routine need or for cardiocirculatory assessment. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: One echocardiographic cardiac output measurement was compared with the corresponding MostCare cardiac output value per patient, considering different ICU admission categories and clinical conditions. For statistical analysis, we used Bland-Altman and linear regression analyses. To assess heterogeneity in results of individual centers, Cochran Q, and the I statistics were applied. A total of 400 paired echocardiographic cardiac output and MostCare cardiac output measures were compared. MostCare cardiac output values ranged from 1.95 to 9.90 L/min, and echocardiographic cardiac output ranged from 1.82 to 9.75 L/min. A significant correlation was found between echocardiographic cardiac output and MostCare cardiac output (r = 0.85; p < 0.0001). Among the different ICUs, the mean bias between echocardiographic cardiac output and MostCare cardiac output ranged from -0.40 to 0.45 L/min, and the percentage error ranged from 13.2% to 47.2%. Overall, the mean bias was -0.03 L/min, with 95% limits of agreement of -1.54 to 1.47 L/min and a relative percentage error of 30.1%. The percentage error was 24% in the sepsis category, 26% in the trauma category, 30% in the surgical category, and 33% in the medical admission category. The final overall percentage error was 27.3% with a 95% CI of 22.2-32.4%. CONCLUSIONS: Our results suggest that MostCare could be an alternative to echocardiography to assess cardiac output in ICU patients with a large spectrum of clinical conditions.

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.

Effect of Conservative vs Conventional Oxygen Therapy on Mortality Among Patients in an Intensive Care Unit: The Oxygen-ICU Randomized Clinical Trial.

Importance: Despite suggestions of potential harm from unnecessary oxygen therapy, critically ill patients spend substantial periods in a hyperoxemic state. A strategy of controlled arterial oxygenation is thus rational but has not been validated in clinical practice. Objective: To assess whether a conservative protocol for oxygen supplementation could improve outcomes in patients admitted to intensive care units (ICUs). Design, Setting, and Patients: Oxygen-ICU was a single-center, open-label, randomized clinical trial conducted from March 2010 to October 2012 that included all adults admitted with an expected length of stay of 72 hours or longer to the medical-surgical ICU of Modena University Hospital, Italy. The originally planned sample size was 660 patients, but the study was stopped early due to difficulties in enrollment after inclusion of 480 patients. Interventions: Patients were randomly assigned to receive oxygen therapy to maintain Pao2 between 70 and 100 mm Hg or arterial oxyhemoglobin saturation (Spo2) between 94% and 98% (conservative group) or, according to standard ICU practice, to allow Pao2 values up to 150 mm Hg or Spo2 values between 97% and 100% (conventional control group). Main Outcomes and Measures: The primary outcome was ICU mortality. Secondary outcomes included occurrence of new organ failure and infection 48 hours or more after ICU admission. Results: A total of 434 patients (median age, 64 years; 188 [43.3%] women) received conventional (n = 218) or conservative (n = 216) oxygen therapy and were included in the modified intent-to-treat analysis. Daily time-weighted Pao2 averages during the ICU stay were significantly higher (P < .001) in the conventional group (median Pao2, 102 mm Hg [interquartile range, 88-116]) vs the conservative group (median Pao2, 87 mm Hg [interquartile range, 79-97]). Twenty-five patients in the conservative oxygen therapy group (11.6%) and 44 in the conventional oxygen therapy group (20.2%) died during their ICU stay (absolute risk reduction [ARR], 0.086 [95% CI, 0.017-0.150]; relative risk [RR], 0.57 [95% CI, 0.37-0.90]; P = .01). Occurrences were lower in the conservative oxygen therapy group for new shock episode (ARR, 0.068 [95% CI, 0.020-0.120]; RR, 0.35 [95% CI, 0.16-0.75]; P = .006) or liver failure (ARR, 0.046 [95% CI, 0.008-0.088]; RR, 0.29 [95% CI, 0.10-0.82]; P = .02) and new bloodstream infection (ARR, 0.05 [95% CI, 0.00-0.09]; RR, 0.50 [95% CI, 0.25-0.998; P = .049). Conclusions and Relevance: Among critically ill patients with an ICU length of stay of 72 hours or longer, a conservative protocol for oxygen therapy vs conventional therapy resulted in lower ICU mortality. These preliminary findings were based on unplanned early termination of the trial, and a larger multicenter trial is needed to evaluate the potential benefit of this approach. Trial Registration: clinicaltrials.gov Identifier: NCT01319643.