Lateral Femoral Cutaneous Nerve Block or Wound Infiltration Combined with Pericapsular Nerve Group (PENG) Block for Postoperative Analgesia following Total Hip Arthroplasty through Posterior Approach: A Randomized Controlled Trial.

Background: Pericapsular nerve group (PENG) block, although effective for pain management following total hip arthroplasty (THA), does not cover skin analgesia. In this randomized controlled trial, we compared the effectiveness of PENG block combined with lateral femoral cutaneous nerve (LFCN) block or wound infiltration (WI) on postoperative analgesia and functional outcomes. Methods: Fifty patients undergoing posterior-approached THA under spinal anesthesia were randomly allocated to receive LFCN block with 10 mL of 0.5% ropivacaine or WI with 20 mL of 0.5% ropivacaine. In both groups, PENG block was performed by injecting 20 mL of 0.5% ropivacaine. Primary outcomes were static and dynamic pain scores (0-10 numeric rating scale) measured in the first 24 h after surgery. Secondary outcomes included postoperative opioid consumption, functional assessment and length of hospital stay. Results: Postoperative static NRS of patients receiving LFCN was higher than that of patients receiving WI at 6 h but lower at 24 h, with a median (IQR) of 3 (2-4) vs. 2 (1-2) (p < 0.001) and 2 (2-3) vs. 3 (3-4) (p = 0.02), respectively. Static pain scores at 12 h did not show significant differences, with an NRS of 3 (2-4) for WI vs. 3 (3-4) for LFCN (p = 0.94). Dynamic pain and range of movement followed a similar trend. No significant differences were detected in other outcomes. Conclusions: LFCN block was not inferior to WI for postoperative analgesia and functional recovery in association with PENG block during the first postoperative day, although it had worse short-term pain scores. Based on these results, it is reasonable to consider LFCN block as a valid alternative to WI or even a complementary technique added to WI to enhance skin analgesia during the first 24 h after THA. Future studies are expected to confirm this hypothesis and find the best combination between PENG block and other techniques to enhance analgesia after THA.

Epstein-Barr virus, Cytomegalovirus, and Herpes Simplex-1/2 reactivations in critically ill patients with COVID-19.

OBJECTIVES: To assess the incidences of Herpes Simplex-1 and 2 (HSV-1, HSV-2), Cytomegalovirus (CMV), Epstein-Barr Virus (EBV) reactivations in critically ill COVID-19 patients. To determine the association between viral reactivation and in-hospital mortality, Intensive Care Unit Bloodstream infection (ICU-BSI), ventilator-associated pneumonia (VAP). DESIGN: Observational retrospective cohort study. SETTING: COVID-19 Intensive Care Unit. PATIENTS: From November 2020 to May 2021, one hundred and twenty patients with COVID-19 severe pneumonia were enrolled and tested for HSV-1, HSV-2, CMV and EBV at the admission in ICU and weekly until discharge or death. The presence of VAP and ICU-BSI was evaluated according to clinical judgement and specific diagnostic criteria. MEASUREMENTS AND MAIN RESULTS: One hundred and twenty patients were enrolled. Multiple reactivations occurred in 75/120 (63%) patients, single reactivation in 27/120 patients (23%). The most reactivated Herpesvirus was EBV, found in 78/120 (65%) patients. The multivariate analysis demonstrated that viral reactivation is a strong independent risk factor for in-hospital mortality (OR = 2.46, 95% CI 1.02-5.89), ICU-BSI (OR = 2.37, 95% CI 1.06-5.29) and VAP (OR = 2.64, 95% CI 1.20-5.82). CONCLUSIONS: Human Herpesviruses reactivations in critically ill patients with COVID-19 severe Pneumonia are associated with mortality and with a higher risk to develop both VAP and ICU-BSI.

Extracorporeal Membrane Oxygenation in Acute Respiratory Failure due to Hemorrhagic Alveolitis in a Patient with Acute Myeloblastic Leukemia.

Introduction. Extracorporeal membrane oxygenation (ECMO) support for severe acute respiratory distress syndrome (ARDS) is nowadays widely used with notable results on the overall survival as reported in the ELSO registry near to 55% at 90 days. This is the reason why ECMO teams force the use of this extreme technique to several populations, even though there is still a lack of data about its use on hematological patients. Case Report. A 39-year-old woman without a history of previous diseases, but a new diagnosis of acute myeloblastic leukemia (AML) was admitted to intensive care unit (ICU) for worsening hypoxia and respiratory acidosis, presenting an ARDS with PaO2/FiO2 < 100 in spontaneous breathing treated with noninvasive ventilation via full-face mask. Meanwhile, chemotherapy was started leading to a severe bone marrow aplasia that was managed with multiple blood and platelet transfusions. These conditions did not allow physicians to start any invasive approaches. After 14 days, ARDS worsened whereas bone marrow recovered, making possible the beginning of an invasive mechanical ventilation, with low positive end-expiratory pressure and a low tidal volume. Moreover, an immediate extracorporeal CO2 removal (ECCO2R) therapy was added. Despite these efforts, no improvement was achieved, and that is why venovenous ECMO throughout femoral-jugular cannulation was applied. A full protective lung ventilation by ultralow tidal volumes was guaranteed. After 2 weeks of ECMO, a gradual weaning from ECMO support was started and completed after two days. No ECMO-related complications were registered. In the end, the patient started her weaning from the mechanical ventilation and reached 12 hours of spontaneous ventilation in oxygen therapy. Discussion. ECMO is used as a rescue therapy in patients affected by severe respiratory failure with life-threatening hypoxia and respiratory acidosis nonresponsive to other maneuvers. However, immunosuppression and coagulopathies of hematological malignancies are considered relative contraindications for ECMO, while long-lasting respiratory failure represents another relative contraindication to extracorporeal support. ECMO could be a valid option to improve the survival of hematological patients with severe ARDS and thrombocytopenia, and management could change case by case, even if high incidence of recurrency.

The Role of TAP/RS Block in Minor Gynecologic Laparoscopic Surgery: A Randomized Clinical Trial.

OBJECTIVES: The aim of the study was to compare, in patients undergoing minor gynecological laparoscopic procedures, the effects of ultrasound (US)-guided transversus abdominis plane (TAP) + rectus sheath (RS) block versus no TAP/RS block in terms of post-surgical pain control using the numeric pain rating scale (NRS) and the degree of patient satisfaction, according to the main goals of Early Recovery After Surgery (ERAS) programs. The primary outcome is to value the postoperative abdominal pain using NRS in both groups. Secondary outcomes are to evaluate blood values, presence of postoperative nausea and vomiting (PONV), postoperative ileus, level of patient expected satisfaction, time of discharge, length of stay (LOS), and the amounts of additional analgesics required. DESIGN: In this prospective randomized controlled trial, patients were randomly assigned to loco-regional anesthesia (LRA) group, who received TAP and RS block under US guidance, or no loco-regional anesthesia (N-LRA) group. Enrolled patients were randomized 1:1 to either receive bilateral TAP/RS block with ropivacaine or sham treatment (patches were applied on the abdominal wall of the patients under general anesthesia). PARTICIPANTS: All patients aged between 18 and 75 years, with ASA (American Society of Anesthesiologists) physical status 1-2, undergoing laparoscopic minor gynecological surgery, were enrolled. SETTING: The study was conducted to the University of Campus Bio-Medico Hospital of Rome. METHODS: Half an hour before surgery, all patients received gabapentin 300 mg per os. Once the patient underwent general anesthesia, US-guided bilateral TAP/RS block was performed by the anesthesiology team, while the uterine manipulator was positioned by a gynecology resident (not involved in the study). In the operative room, all patients received the same standardized anesthetic regimen. Postoperative abdominal pain was assessed at rest, after palpation, during movement, and after a cough by evaluating the patient at 6, 12, 18, 24, 36, 48, and 72 h after surgery, using the NRS from 0 to 10 in both groups. The amount of drug used for analgesia in the first 48 h after surgery was recorded. Moreover, hemoglobin, white blood cells, and c-reactive protein levels were recorded at 24, 48, and 72 h. The presence of PONV and the postoperative ileus was recorded throughout convalescence. The expected level of patient satisfaction at discharge and finally the LOS were assessed. LIMITATIONS: The major weakness of this study is that 60 mL of 0.5% ropivacaine was administered to each patient, without considering weight differences, yet contemporary literature rarely suggests volume/dose titration in fascial blocks. RESULTS: A total of 104 women, undergoing gynecological minor laparoscopic surgery, were enrolled and assigned to LRA group (53 pts) and N-LRA group (51 pts). Postoperative pain was significantly reduced in patients who received TAP/RS block. A reduction in the intake of non-steroidal anti-inflammatory drugs after surgery was registered in LRA group (p < 0.01). Moreover, a significant reduction of LOS (45.97 ± 9.87 vs. 65.08 ± 17.32 h; p < 0.01) and PONV was observed in the LRA group, as well as a better level of patient satisfaction at discharge (9.43 ± 0.94 vs. 8.26 ± 1.19; p < 0.01), compared to the N-LRA group. CONCLUSIONS: US-guided TAP and RS block significantly reduces postoperative pain after minor gynecologic laparoscopic surgery and improves patients' post-operative recovery.

Perioperative Right Ventricular Dysfunction and Abnormalities of the Tricuspid Valve Apparatus in Patients Undergoing Cardiac Surgery.

Right ventricular (RV) dysfunction frequently occurs after cardiac surgery and is linked to adverse postoperative outcomes, including mortality, reintubation, stroke, and prolonged ICU stays. While various criteria using echocardiography and hemodynamic parameters have been proposed, a consensus remains elusive. Distinctive RV anatomical features include its thin wall, which presents a triangular shape in a lateral view and a crescent shape in a cross-sectional view. Principal causes of RV dysfunction after cardiac surgery encompass ischemic reperfusion injury, prolonged ischemic time, choice of cardioplegia and its administration, cardiopulmonary bypass weaning characteristics, and preoperative risk factors. Post-left ventricular assist device (LVAD) implantation RV dysfunction is common but often transient, with a favorable prognosis upon resolution. There is an ongoing debate regarding the benefits of concomitant surgical repair of the RV in the presence of regurgitation. According to the literature, the gold standard techniques for assessing RV function are cardiac magnetic resonance imaging and hemodynamic assessment using thermodilution. Echocardiography is widely favored for perioperative RV function evaluation due to its accessibility, reproducibility, non-invasiveness, and cost-effectiveness. Although other techniques exist for RV function assessment, they are less common in clinical practice. Clinical management strategies focus on early detection and include intravenous drugs (inotropes and vasodilators), inhalation drugs (pulmonary vasodilators), ventilator strategies, volume management, and mechanical support. Bridging research gaps in this field is crucial to improving clinical outcomes associated with RV dysfunction in the near future.

Efficacy and Safety of Reparixin in Patients with Severe COVID-19 Pneumonia: A Phase 3, Randomized, Double-Blind Placebo-Controlled Study.

INTRODUCTION: Polymorphonuclear cell influx into the interstitial and bronchoalveolar spaces is a cardinal feature of severe coronavirus disease 2019 (COVID-19), principally mediated by interleukin-8 (IL-8). We sought to determine whether reparixin, a novel IL-8 pathway inhibitor, could reduce disease progression in patients hospitalized with severe COVID-19 pneumonia. METHODS: In this Phase 3, randomized, double-blind, placebo-controlled, multicenter study, hospitalized adult patients with severe COVID-19 pneumonia were randomized 2:1 to receive oral reparixin 1200 mg three times daily or placebo for up to 21 days or until hospital discharge. The primary endpoint was the proportion of patients alive and free of respiratory failure at Day 28, with key secondary endpoints being the proportion of patients free of respiratory failure at Day 60, incidence of intensive care unit (ICU) admission by Day 28 and time to recovery by Day 28. RESULTS: Of 279 patients randomized, 182 received at least one dose of reparixin and 88 received placebo. The proportion of patients alive and free of respiratory failure at Day 28 was similar in the two groups {83.5% versus 80.7%; odds ratio 1.63 [95% confidence interval (CI) 0.75, 3.51]; p = 0.216}. There were no statistically significant differences in the key secondary endpoints, but a numerically higher proportion of patients in the reparixin group were alive and free of respiratory failure at Day 60 (88.7% versus 84.6%; p = 0.195), fewer required ICU admissions by Day 28 (15.8% versus 21.7%; p = 0.168), and a higher proportion recovered by Day 28 compared with placebo (81.6% versus 74.9%; p = 0.167). Fewer patients experienced adverse events with reparixin than placebo (45.6% versus 54.5%), most mild or moderate intensity and not related to study treatment. CONCLUSIONS: This trial did not meet the primary efficacy endpoints, yet reparixin showed a trend toward limiting disease progression as an add-on therapy in COVID-19 severe pneumonia and was well tolerated. TRIAL REGISTRATION: ClinicalTrials.gov: NCT04878055, EudraCT: 2020-005919-51.

The specialized pro-resolving lipid mediator Protectin D1 affects macrophages differentiation and activity in Adult-onset Still's disease and COVID-19, two hyperinflammatory diseases sharing similar transcriptomic profiles.

Introduction: COVID-19 and autoinflammatory diseases, such as Adult-onset Still's Disease (AOSD), are characterized by hyperinflammation, in which it is observed massive production and uncontrolled secretion of pro-inflammatory cytokines. The specialized pro-resolving lipid mediators (SPMs) family is one the most important processes counteracting hyperinflammation inducing tissue repair and homeostasis restoration. Among SPMs, Protectin D1 (PD1) is able to exert antiviral features, at least in animal models. The aim of this study was to compare the transcriptome of peripheral blood mononuclear cells (PBMCs) from patients with AOSD and COVID-19 and to evaluate the role of PD1 on those diseases, especially in modulating macrophages polarization. Methods: This study enrolled patients with AOSD, COVID-19, and healthy donors HDs, undergoing clinical assessment and blood sample collection. Next-generation deep sequencing was performed to identify differences in PBMCs transcripts profiles. Plasma levels of PD1 were assessed by commercial ELISA kits. Monocyte-derived macrophages were polarized into M1 and M2 phenotypes. We analyzed the effect of PD1 on macrophages differentiation. At 10 days, macrophages were analyzed for surface expression of subtypes markers by flow cytometry. Cytokines production was measured in supernatants by Bio-Plex Assays. Results: In the transcriptomes from AOSD patients and COVID-19 patients, genes involved in inflammation, lipid catabolism, and monocytes activation were specifically dysregulated in AOSD and COVID-19 patients when compared to HDs. Patients affected by COVID-19, hospitalized in intensive care unit (ICU), showed higher levels of PD1 when compared to not-ICU hospitalized patients and HDs (ICU COVID-19 vs not-ICU COVID-19, p= 0.02; HDs vs ICU COVID-19, p= 0.0006). PD1 levels were increased in AOSD patients with SS ≥1 compared to patients with SS=0 (p=0.028) and HDs (p=0.048). In vitro treatment with PD1 of monocytes-derived macrophages from AOSD and COVID-19 patients induced a significant increase of M2 polarization vs control (p<0.05). Furthermore, a significant release of IL-10 and MIP-1ß from M2 macrophages was observed when compared to controls (p<0.05). Discussion: PD1 is able to induce pro-resolutory programs in both AOSD and COVID-19 increasing M2 polarization and inducing their activity. In particular, PD1-treated M2 macrophages from AOSD and COVID-19 patients increased the production of IL-10 and enhanced homeostatic restoration through MIP-1ß production.

The similar expression of both ferritin and scavenger receptors activation genes in patients with COVID19 and AOSD support their role in the pathogenesis of these diseases and identify a common mechanism at the basis of the "hyperferritinemic syndromes".

A role for COVID19 in "hyperferritinemic syndromes" has been proposed based on its clinical and serological characteristics and its similarities with AOSD. To better understand the molecular pathways responsible of these similarities, we evaluated in the PBMCs of 4 active AOSD patients, 2 COVID19 patients with ARDS, and 2 HCs the expression of genes associated with iron metabolisms, with monocyte/macrophages activation, and finally with NETs formation.

Ultrasound Guided Parasternal Block for Perioperative Analgesia in Cardiac Surgery: A Prospective Study.

Ultrasound guided parasternal block is a regional anaesthesia technique targeting the anterior branches of intercostal nerves, which supply the anterior thoracic wall. The aim of this prospective study is to assess the efficacy of parasternal block to manage postoperative analgesia and reduce opioid consumption in patients undergoing cardiac surgery throughout sternotomy. A total of 126 consecutive patients were allocated to two different groups, receiving (Parasternal group) or not (Control group) preoperative ultrasound guided bilateral parasternal block with 20 mL of 0.5% ropivacaine per side. The following data were recorded: postoperative pain expressed by a 0-10 numeric rating scale (NRS), intraoperative fentanyl consumption, postoperative morphine consumption, time to extubation and perioperative pulmonary performance at incentive spirometry. Postoperative NRS was not significantly different between Parasternal and Control groups with a median (IQR) of 2 (0-4.5) vs. 3 (0-6) upon awakening (p = 0.07); 0 (0-3) vs. 2 (0-4) at 6 h (p = 0.46); 0 (0-2) vs. 0 (0-2) at 12 h (p = 0.57). Postoperative morphine consumption was similar among groups. However, intraoperative fentanyl consumption was significantly lower in the Parasternal group [406.3 ± 81.6 mcg vs. 864.3 ± 154.4, (p < 0.001)]. Parasternal group showed shorter times to extubation [(191 ± 58 min vs. 305 ± 72 min, (p)] and better performance at incentive spirometer with a median (IQR) of 2 raised balls (1-2) vs. 1 (1-2) after awakening (p = 0.04). Ultrasound guided parasternal block provided an optimal perioperative analgesia with a significant reduction in intraoperative opioid consumption, time to extubation and a better postoperative performance at spirometry when compared to the Control group.

Ultrasound predictors of difficult spinal anesthesia: a prospective single-blind observational study.

BACKGROUND: Ultrasound showed to improve the precision and efficacy of spinal anesthesia (SA) through the identification of specific structures surrounding the intrathecal space, such as the anterior and posterior complex of dura mater (DM). The aim of this study was to verify the efficacy of ultrasonography in predicting difficult SA trough the analysis of different ultrasound patterns. METHODS: This prospective single-blind observational study involved 100 patients undergoing orthopedic or urological surgery. A first operator chose by landmarks the intervertebral space where he wanted to perform SA. Then a second operator recorded the visibility of DM complexes at ultrasound. Subsequently, the first operator, blinded to the ultrasound evaluation, performed SA, defined as "difficult" in case of failure, change of intervertebral space, operator exchange, duration >400 seconds or more than 10 needle passes. RESULTS: The ultrasound visualization of only posterior complex or the failure in visualization of both complexes showed a positive predictive value of 76% and 100%, respectively, towards difficult SA vs. 6% when both complexes were visible; P<0.001. A negative correlation was found between the number of visible complexes and both patients' age and BMI. Landmark-guided evaluation underestimated the intervertebral level in 30% of cases. CONCLUSIONS: Ultrasound showed a high accuracy in detecting difficult spinal anesthesia and its use should be recommended in the daily clinical practice in order to increase success rate and minimize patient discomfort. The absence of both DM complexes at ultrasound should lead the anesthetist to evaluate other intervertebral levels or consider alternative techniques.

Parasternal Intercostal Nerve Blocks in Patients Undergoing Cardiac Surgery: Evidence Update and Technical Considerations.

In the Enhanced Recovery After Surgery era, parasternal intercostal nerve block has been proposed to improve pain control and reduce opioid use in patients undergoing cardiac surgery. However current literature has reported conflicting evidence about the effect of this multimodal pain management, as procedural variations might pose a significant bias on outcomes evaluation. In this setting, the infiltration of the parasternal plane into 2 intercostal spaces, second and fifth, with a local anesthetic spread under or above the costal plane with ultrasound guidance, seem to be standardized in theory, but significant differences might be observed in clinical practice. This narrative review summarizes and defines the optimal techniques for parasternal plane blocks in patients undergoing cardiac surgery with full median sternotomy, considering both pectointercostal fascial block and transversus thoracic plane block. A total of 10 randomized trials have been published, in adjunct to observational studies, which are heterogeneous in terms of techniques, methods, and outcomes. Parasternal block has been shown to reduce perioperative opioid consumption and provide a more favorable analgesic profile, with reduced postoperative opioid-related side effects. A trend toward reduced intensive care unit stay or duration of mechanical ventilation should be confirmed by adequately powered randomized trials or registry studies. Differences in operative technique might impact outcomes and, therefore, standardization of the procedure plays a pivotal role before reporting specific outcomes. Parasternal plane blocks might significantly improve outcomes of cardiac surgery with full median sternotomy, and should be introduced comprehensively in Enhanced Recovery After Surgery protocols.

Linezolid Intoxication with Extreme Lactate Blood Levels Successfully Treated with Dialytic Treatment in ICU: A Case Report.

INTRODUCTION: Lactic acidosis is a rare but life-threatening complication associated with prolonged linezolid therapy. No specific treatment is suggested, except for antibiotic therapy interruption. CASE REPORT: A 70-years-old woman faced severe linezolid intoxication after antibiotics therapy initiation for infection of a surgical sternal wound. The patient suffered from a severe increment of blood lactate and thrombocytopenia. She was admitted to ICU twice, and due to dialytic treatment, linezolid and lactate serum levels came back to normality. CONCLUSION: More studies should be conducted to evaluate the human tissue storage sites of linezolid and the influence of various factors on its clearance and plasma concentrations in critically ill patients.

Modified Colistin Regimen for Critically Ill Patients with Acute Renal Impairment and Continuous Renal Replacement Therapy.

Colistin is a last resort antibiotic to treat multidrug-resistant Gram-negative bacteria infections. Colistin is administered intravenously in the form of its inactive prodrug colistin methanesulfonate (CMS). For patients with acute kidney impairment and continuous renal replacement therapy high extracorporeal clearance may cause a substantial removal of active colistin from the bloodstream, eventually decreasing its antibacterial efficacy. Currently recommended doses of CMS may therefore be inadequate for these patients. We report on the potential value of a modified regimen that adopts a loading dose of CMS (bolus of 9 MU vs. conventional 3 MU every 8 h), followed by maintenance (3 MU every 8 h). Preliminary pharmacokinetic evidence for the feasibility and efficacy of this regimen is described for 2 patients.

A New Pressure Guided Management Tool for Epidural Space Detection: Feasibility Assessment on a Simulator.

The detection of epidural space is usually performed by the technique of loss of resistance (LOR) without technological support, although there are few commercial options. We sought to design and develop a new noninvasive system able to detect the LOR without any changes to the conventional procedure. It allows detecting the LOR by a custom made algorithm. The system provides a visual and acoustic feedback when the LOR is detected. We optimized the detection algorithm and investigated the performance of the system during experiments on a custom simulator. During the experiments performed by 10 anesthetists and 10 trainees, the pressure exerted on the syringe plunger was monitored using the custom-made system. Each participant performed four experiments using the system on the simulator. The performance of the system in LOR detection was evaluated comparing the feedback activation and the breaches of the last layer of the simulator. Moreover, each participant filled out a questionnaire to assess how the procedure with the simulator mimics the clinical scenario. A higher questionnaire score corresponds to a more realistic condition (0 = not real, 5 = extremely real). Results showed that the LOR was detected in 74 of the 80 trials (92.5% of the cases); the anesthetists obtained better results than trainees: 97.5 versus 87.5%. The questionnaires showed that all the participants found the trial realistic (score ≥3); anesthetists found it more realistic than trainees (4.2 ± 0.78 vs. 3.8 ± 0.78, mean ± SD). In summary, the proposed system successfully detected the LOR in the large part of the trials. The participants found the trials realistic. A higher success rate was observed in the anesthetists group.

Non-invasive cardiac output evaluation in postoperative cardiac surgery patients, using a new prolonged expiration-based technique.

The gold standard methods to measure cardiac output (CO) are invasive and expose the patient to high risks of various complications. The aim of this study is to assess an innovative non-invasive method for CO monitoring in mechanically ventilated patients after cardiac surgery and its agreement with values obtained by thermodilution technique. Continuous monitoring of respiratory gas concentrations and airflow allows the estimation of CO through a newly developed algorithm derived from a modified version of the Fick equation. It consists of two phases: the first involves measurements during steady breathing state, and the second starts when a sudden perturbation into the carbon dioxide elimination process is introduced by a prolonged expiration. This prospective clinical study involved thirty-five adult patients, undergone cardiac surgery. The measurements were performed in curarized and haemodynamically stable patients, during the post-surgery recovery in intensive care unit. The study protocol, which lasted 1 h for each patient, consisted of 20 measurements obtained by prolonged expiration-based method and 10 by thermodilution. The estimation of CO using the proposed method (COK) agreed with the thermodilution (COT) as demonstrated by: a low mean bias between COK and COT considering all patients (i.e., -0.11 L min(-1)); a best fitting line having slope = 0.98, r = 0.81, p < 0.0001; the lower and upper limits of agreement were -0.77 and +0.54 L min(-1), respectively. COK shows a mean percentage error of 34 %. In stable mechanically ventilated patients, undergone cardiac surgery, the proposed method is reliable if compared to the thermodilution. Considering the non-invasivity of the technique, further evaluations of its performances are encouraged.