Transcranial Doppler and Color-Coded Doppler Use for Brain Death Determination in Adult Patients: A Pictorial Essay.

Transcranial Doppler (TCD) is a repeatable, at-the-bedside, helpful tool for confirming cerebral circulatory arrest (CCA). Despite its variable accuracy, TCD is increasingly used during brain death determination, and it is considered among the optional ancillary tests in several countries. Among its limitations, the need for skilled operators with appropriate knowledge of typical CCA patterns and the lack of adequate acoustic bone windows for intracranial arteries assessment are critical. The purpose of this review is to describe how to evaluate cerebral circulatory arrest in the intensive care unit with TCD and transcranial duplex color-coded doppler (TCCD).

Feasibility and safety of deep sedation with propofol and remifentanil in spontaneous breathing during endoscopic retrograde cholangiopancreatography: an observational prospective study.

BACKGROUND: Endoscopic retrograde cholangiopancreatography (ERCP) is an interventional procedure that requires deep sedation or general anaesthesia. The purpose of this prospective observational study was to assess the feasibility and safety of deep sedation in ERCP to maintain spontaneous breathing. METHODS: This is a single-centre observational prospective cohort study conducted in a tertiary referral university hospital. All consecutive patients who needed sedation or general anaesthesia for ERCP were included from January 2021 to June 2021. Deep sedation was achieved and maintained by continuous infusion of an association of propofol and remifentanil. The primary endpoint was to assess the prevalence of major anaesthesia-related complications, such as arrhythmias, hypotension, gas exchange dysfunction, and vomiting (safety endpoint). Secondary endpoints were: (a) to assess the prevalence of signs of an insufficient level of sedation, such as movement, cough, and hiccups (feasibility endpoint): (b) time needed to achieve the target level of sedation and for recovery from anaesthesia. In order to do so we collect the following parameters: peripheral oxygen saturation, fraction of inspired oxygen, noninvasive systemic blood pressure, heart rate, number of breaths per minute, neurological functions with the use of the bispectral index to determine depth of anaesthesia, and partially exhaustive CO2 end pressure to continuously assess the ventilatory status. The collected data were analysed by several tests: Shapiro-Wilk, Student's t, Tuckey post-hoc, Wilcoxon rank-sum and Kruskall-Wallis ran. Statistical analysis was performed using Stata/BE 17.0 (StataCorp LLC). RESULTS: 114 patients were enroled. Eight patients were excluded because they did not meet the inclusion criteria. We found that all patients were hemodynamically stable: intraoperative mean systolic blood pressure was 139,23 mmHg, mean arterial pressure was on average 106,66 mmHg, mean heart rate was 74,471 bpm. The mean time to achieve the target level of sedation was 63 s, while the mean time for the awakening after having stopped drug infusion was 92 s. CONCLUSIONS: During ERCP, deep sedation and analgesia using the association of propofol and remifentanil and maintaining spontaneous breathing are safe and feasible, allowing for a safe and quick recovery from anaesthesia.

Perfluorocarbons in Research and Clinical Practice: A Narrative Review.

Perfluorocarbons (PFCs) are organic liquids derived from hydrocarbons in which some of the hydrogen atoms have been replaced by fluorine atoms. They are chemically and biologically inert substances with a good safety profile. They are stable at room temperature, easy to store, and immiscible in water. Perfluorocarbons have been studied in biomedical research since 1960 for their unique properties as oxygen carriers. In particular, PFCs have been used for liquid ventilation in unusual environments such as deep-sea diving and simulations of zero gravity, and more recently for drug delivery and diagnostic imaging. Additionally, when delivered as emulsions, PFCs have been used as red blood cell substitutes. This narrative review will discuss the multifaceted utilization of PFCs in therapeutics, diagnostics, and research. We will specifically emphasize the potential role of PFCs as red blood cell substitutes, as airway mechanotransducers during artificial placenta procedures, as a means to improve donor organ perfusion during the ex vivo assessment, and as an adjunct in cancer therapies because of their ability to reduce local tissue hypoxia.

Brain tissue oxygenation monitoring in subarachnoid hemorrhage for the detection of delayed ischemia: a systematic review and meta-analysis.

INTRODUCTION: Subarachnoid hemorrhage (SAH) is a severe subtype of stroke which can be caused by the rupture of an intracranial aneurysm. Following SAH, about 30% of patients develop a late neurologic deterioration due to a delayed cerebral ischemia (DCI). This is a metanalysis and systematic review on the association between values of brain tissue oxygenation (PbtO2) and DCI in patients with SAH. EVIDENCE ACQUISITION: The protocol was written according to the PRISMA-P (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines and approved by the International Prospective Register of Systematic Reviews (PROSPERO registration number CRD42021229338). Relevant literature published up to August 1, 2022 was systematically searched throughout the databases MEDLINE, WEB OF SCIENCE, SCOPUS. A systematic review and metanalysis was carried out. The studies considered eligible were those published in English; that enrolled adult patients (≥18years) admitted to neurointensive care units with aneurysmal SAH (aSAH); that reported presence of multimodality monitoring including PbtO2 and detection of DCI during the period of monitoring. EVIDENCE SYNTHESIS: We founded 286 studies, of which six considered eligible. The cumulative mean of PbtO2 was 19.5 mmHg in the ischemic group and 24.1mmHg in the non ischemic group. The overall mean difference of the values of PbtO2 between the patients with or without DCI resulted significantly different (-4.32 mmHg [IC 95%: -5.70, -2.94], without heterogeneity, I2 = 0%, and a test for overall effect with P<0.00001). CONCLUSIONS: PbtO2 values were significantly lower in patients with DCI. Waiting for definitive results, monitoring of PbtO2 should be considered as a complementary parameter for multimodal monitoring of the risk of DCI in patients with SAH.

Respective Effects of Helmet Pressure Support, Continuous Positive Airway Pressure, and Nasal High-Flow in Hypoxemic Respiratory Failure: A Randomized Crossover Clinical Trial.

Rationale: The respective effects of positive end-expiratory pressure (PEEP) and pressure support delivered through the helmet interface in patients with hypoxemia need to be better understood. Objectives: To assess the respective effects of helmet pressure support (noninvasive ventilation [NIV]) and continuous positive airway pressure (CPAP) compared with high-flow nasal oxygen (HFNO) on effort to breathe, lung inflation, and gas exchange in patients with hypoxemia (PaO2/FiO2 ⩽ 200). Methods: Fifteen patients underwent 1-hour phases (constant FiO2) of HFNO (60 L/min), helmet NIV (PEEP = 14 cm H2O, pressure support = 12 cm H2O), and CPAP (PEEP = 14 cm H2O) in randomized sequence. Measurements and Main Results: Inspiratory esophageal (ΔPES) and transpulmonary pressure (ΔPL) swings were used as surrogates for inspiratory effort and lung distension, respectively. Tidal Volume (Vt) and end-expiratory lung volume were assessed with electrical impedance tomography. ΔPES was lower during NIV versus CPAP and HFNO (median [interquartile range], 5 [3-9] cm H2O vs. 13 [10-19] cm H2O vs. 10 [8-13] cm H2O; P = 0.001 and P = 0.01). ΔPL was not statistically different between treatments. PaO2/FiO2 ratio was significantly higher during NIV and CPAP versus HFNO (166 [136-215] and 175 [158-281] vs. 120 [107-149]; P = 0.002 and P = 0.001). NIV and CPAP similarly increased Vt versus HFNO (mean change, 70% [95% confidence interval (CI), 17-122%], P = 0.02; 93% [95% CI, 30-155%], P = 0.002) and end-expiratory lung volume (mean change, 198% [95% CI, 67-330%], P = 0.001; 263% [95% CI, 121-407%], P = 0.001), mostly due to increased aeration/ventilation in dorsal lung regions. During HFNO, 14 of 15 patients had pendelluft involving >10% of Vt; pendelluft was mitigated by CPAP and further by NIV. Conclusions: Compared with HFNO, helmet NIV, but not CPAP, reduced ΔPES. CPAP and NIV similarly increased oxygenation, end-expiratory lung volume, and Vt, without affecting ΔPL. NIV, and to a lesser extent CPAP, mitigated pendelluft. Clinical trial registered with clinicaltrials.gov (NCT04241861).

Transcranial Doppler as a screening test to exclude intracranial hypertension in brain-injured patients: the IMPRESSIT-2 prospective multicenter international study.

BACKGROUND: Alternative noninvasive methods capable of excluding intracranial hypertension through use of transcranial Doppler (ICPtcd) in situations where invasive methods cannot be used or are not available would be useful during the management of acutely brain-injured patients. The objective of this study was to determine whether ICPtcd can be considered a reliable screening test compared to the reference standard method, invasive ICP monitoring (ICPi), in excluding the presence of intracranial hypertension. METHODS: This was a prospective, international, multicenter, unblinded, diagnostic accuracy study comparing the index test (ICPtcd) with a reference standard (ICPi), defined as the best available method for establishing the presence or absence of the condition of interest (i.e., intracranial hypertension). Acute brain-injured patients pertaining to one of four categories: traumatic brain injury (TBI), subarachnoid hemorrhage (SAH), intracerebral hemorrhage (ICH) or ischemic stroke (IS) requiring ICPi monitoring, were enrolled in 16 international intensive care units. ICPi measurements (reference test) were compared to simultaneous ICPtcd measurements (index test) at three different timepoints: before, immediately after and 2 to 3 h following ICPi catheter insertion. Sensitivity, specificity, positive (PPV) and negative predictive values (NPV) were calculated at three different ICPi thresholds (> 20, > 22 and > 25 mmHg) to assess ICPtcd as a bedside real-practice screening method. A receiver operating characteristic (ROC) curve analysis with the area under the curve (AUC) was used to evaluate the discriminative accuracy and predictive capability of ICPtcd. RESULTS: Two hundred and sixty-two patients were recruited for final analysis. Intracranial hypertension (> 22 mmHg) occurred in 87 patients (33.2%). The total number of paired comparisons between ICPtcd and ICPi was 687. The NPV was elevated (ICP > 20 mmHg = 91.3%, > 22 mmHg = 95.6%, > 25 mmHg = 98.6%), indicating high discriminant accuracy of ICPtcd in excluding intracranial hypertension. Concordance correlation between ICPtcd and ICPi was 33.3% (95% CI 25.6-40.5%), and Bland-Altman showed a mean bias of -3.3 mmHg. The optimal ICPtcd threshold for ruling out intracranial hypertension was 20.5 mmHg, corresponding to a sensitivity of 70% (95% CI 40.7-92.6%) and a specificity of 72% (95% CI 51.9-94.0%) with an AUC of 76% (95% CI 65.6-85.5%). CONCLUSIONS AND RELEVANCE: ICPtcd has a high NPV in ruling out intracranial hypertension and may be useful to clinicians in situations where invasive methods cannot be used or not available. TRIAL REGISTRATION: NCT02322970 .

Neo-ECHOTIP: A structured protocol for ultrasound-based tip navigation and tip location during placement of central venous access devices in neonates.

Central venous access devices are often needed in neonates admitted to Neonatal Intensive Care Unit. The location of the tip of the central catheter is usually assessed by post-procedural X-ray. However, this strategy is inaccurate and time consuming. Recent guidelines strongly recommend intra-procedural methods of tip location, to increase the cost-effectiveness of the maneuver and to shorten the time between device placement and utilization. In this regard, real-time ultrasound represents the most promising tool for tip navigation and location in neonates. The aim of this paper is (a) to review all the evidence available about ultrasound-based tip navigation and tip location of central catheters in the neonatal population (b) to propose a novel protocol for tip navigation and location (Neo-ECHOTIP) based on such evidence.

Lung ultrasound predicts non-invasive ventilation outcome in COVID-19 acute respiratory failure: a pilot study.

BACKGROUND: The aim of this study is to determine relationships between lung aeration assessed by lung ultrasound (LUS) with non-invasive ventilation (NIMV) outcome, intensive care unit (ICU) admission and mechanical ventilation (MV) needs in COVID-19 respiratory failure. METHODS: A cohort of adult patients with COVID-19 respiratory failure underwent LUS during initial assessment. A simplified LUS protocol consisting in scanning six areas, three for each side, was adopted. A score from 0 to 3 was assigned to each area. Comprehensive LUS score (LUSsc) was calculated as the sum of the score in all areas. LUSsc, the amount of involved sonographic lung areas (LUSq), the number of lung quadrants radiographically infiltrated and the degree of oxygenation impairment at admission (SpO2/FiO2 ratio) were compared to NIMV Outcome, MV needs and ICU admission. RESULTS: Among 85 patients prospectively included in the analysis, 49 of 61 needed MV. LUSsc and LUSq were higher in patients who required MV (median 12 [IQR 8-14] and median 6 [IQR 4-6], respectively) than in those who did not (6 [IQR 2-9] and 3 [IQR 1-5], respectively), both P<0.001. NIMV trial failed in 26 patients out 36. LUSsc and LUSq were significantly higher in patients who failed NIMV than in those who did not. From ROC analysis, LUSsc ≥12 and LUSq ≥5 gave the best cut-off values for NIMV failure prediction (AUC=0.95, 95%CI 0.83-0.99 and AUC=0.81, 95% CI 0.65-0.91, respectively). CONCLUSIONS: Our data suggest LUS as a possible tool for identifying patients who are likely to require MV and ICU admission or to fail a NIMV trial.

Rapid Femoral Vein Assessment (RaFeVA): A systematic protocol for ultrasound evaluation of the veins of the lower limb, so to optimize the insertion of femorally inserted central catheters.

In this paper we describe a new protocol-named RaFeVA (Rapid Femoral Vein Assessment)-for the systematic US assessment of the veins in the inguinal area and at mid-thigh, designed to evaluate patency and caliber of the common and superficial femoral veins and choose the best venipuncture site before insertion of a FICC.

European Society of Anaesthesiology and Intensive Care Guidelines on peri-operative use of ultrasound for regional anaesthesia (PERSEUS regional anesthesia): Peripheral nerves blocks and neuraxial anaesthesia.

Nowadays, ultrasound-guidance is commonly used in regional anaesthesia (USGRA) and to locate the spinal anatomy in neuraxial analgesia. The aim of this second guideline on the PERi-operative uSE of UltraSound (PERSEUS-RA) is to provide evidence as to which areas of regional anaesthesia the use of ultrasound guidance should be considered a gold standard or beneficial to the patient. The PERSEUS Taskforce members were asked to define relevant outcomes and rank the relative importance of outcomes following the GRADE process. Whenever the literature was not able to provide enough evidence, we decided to use the RAND method with a modified Delphi process. Whenever compared with alternative techniques, the use of USGRA is considered well tolerated and effective for some nerve blocks but there are certain areas, such as truncal blocks, where a lack of robust data precludes useful comparison. The new frontiers for further research are represented by the application of USG during epidural analgesia or spinal anaesthesia as, in these cases, the evidence for the value of the use of ultrasound is limited to the preprocedure identification of the anatomy, providing the operator with a better idea of the depth and angle of the epidural or spinal space. USGRA can be considered an essential part of the curriculum of the anaesthesiologist with a defined training and certification path. Our recommendations will require considerable changes to some training programmes, and it will be necessary for these to be phased in before compliance becomes mandatory.

A novel ultrasound-guided approach to the axillary vein: Oblique-axis view combined with in-plane puncture.

INTRODUCTION: Ultrasound-guided cannulation of the axillary vein in the infraclavicular area has several potential advantages for both short-term and long-term venous access devices. Currently, there are two techniques to approach axillary vein for ultrasound-guided cannulation: out-of-plane puncture in the short-axis view and the in-plane puncture in the long-axis view. We propose a novel ultrasound-guided puncture technique of axillary vein for centrally inserted central catheter placement, which consists in the oblique-axis view of the axillary vein coupled with the in-plane puncture. The main objectives of this study were feasibility and safety of this approach. The primary endpoints were the success rate and early complications; the secondary endpoints were late complications. METHODS: We analyzed data from a retrospective cohort of 80 ultrasound-guided cannulation of axillary vein performed with the oblique axis-in-plane technique in 80 cancer patients requiring a totally implantable central venous access, at CRO Aviano National Cancer Institute, during the period from January 2016 up to October 2017. We focused on the percentage of successful venous cannulation at the first attempt and on the cumulative incidence of early and late complications. RESULTS: Axillary vein cannulation was successful at the first attempt in 77 out of 80 patients (96%). We had no significant complications during placement or in the first 48 h. The total number of catheter days was 27,432. The cumulative incidence of catheter-related bloodstream infection was of 0.036 per 1000 catheter days (only one case). We had no infection of the pocket of the reservoir, no symptomatic venous thrombosis, and no catheter migration. CONCLUSION: Our data show that the oblique axis-in-plane technique of the ultrasound approach to the axillary vein is feasible and safe.

A modified intracavitary electrocardiographic method for detecting the location of the tip of central venous catheters in atrial fibrillation patients.

INTRODUCTION: The intracavitary electrocardiographic method is recommended for assessing the location of the tip of central venous catheter when there is an identifiable P wave. Previous reports suggested that intracavitary electrocardiographic method might also be applied to patients with atrial fibrillation, considering the so-called f waves as a surrogate of the P wave. METHODS: We studied 18 atrial fibrillation patients requiring simultaneously a central venous catheter and a trans-esophageal echocardiography. An intracavitary electrocardiographic trace was recorded with the catheter tip in three different positions defined by trans-esophageal echocardiography imaging: in the superior vena cava, 2 cm above the cavo-atrial junction; at the cavo-atrial junction; and in the right atrium, 2 cm below the cavo-atrial junction. Three different criteria of measurement of the f wave pattern in the TQ tract were used: the mean height of f waves (method A); the height of the highest f wave (method B); the difference between the highest positive peak and the lowest negative peak (method C). RESULTS: There were no complications. With the tip placed at the cavo-atrial junction, the mean value of the f waves was significantly higher than in the other two positions. All three methods were effective in discriminating the tip position at the cavo-atrial junction, though method B proved to be the most accurate. CONCLUSION: A modified intracavitary electrocardiographic technique can be safely used for detecting the location of the tip of central venous catheters in atrial fibrillation patients: the highest activity of the f waves is an accurate indicator of the location of the tip at the cavo-atrial junction.

Clinical Outcomes and Prognostic Factors for Spontaneous Intracerebral Hemorrhage in Pediatric ICU: A 12-Year Experience.

BACKGROUND: In the pediatric population, spontaneous intracerebral hemorrhage (sICH) is as common as ischemic stroke and accounts for significant mortality and morbidity. Differently from the ischemic stroke, there are few guidelines for directing management of sICH. This article aims to analyze both clinical outcomes and prognostic factors in order to produce tools for the design of prospective randomized studies addressed to implement treatment of pediatric sICH. METHODS: Twelve-year retrospective review of a single-center consecutivesICH pediatric cases admitted to the pediatric intensive care unit (PICU). Selected end points were survival, PICU stay, and dichotomized Glasgow Outcome Score (GOS), with recovery and moderate disability (GOS 4-5) classified as favorable outcome and vegetative state or severe disability (GOS 2-3) classified as unfavorable. RESULTS: Data of 107 children younger than 14 years admitted to our PICU due to sICH were analyzed. Overall PICU mortality was 24.2%. On multivariate analysis, the single factor markedly influencing survival was the presence of midline shift (P = .002). In PICU survivors, there were 42 GOS 2-3 and 39 GOS 4-5. A low Glasgow Coma Scale (GCS) on PICU admission was predictive of severe neurological impairment in survivors (P = .003). Intraventricular hemorrhage and infratentorial origin did not influence outcome in this series. CONCLUSION: The severity of presentation of sICH expressed by the midline shift and the GCS at PICU admission are significant prognostic factors for survival and neurological outcome. Some prognostic factors of the adult population have not been confirmed.

Size and shape of the inferior vena cava before and after a fluid challenge: a pilot study.

BACKGROUND: Recent meta-analyses failed to support the reliability of ultrasound assessment of the inferior vena cava (IVC) to predict fluid responsiveness. However, the techniques utilized were heterogeneous. We hypothesized that the variability of the elliptic section and caliber of the IVC along its course may influence ultrasound evaluation. Therefore, we investigated IVC size and shape at four levels, before and after a fluid challenge. METHODS: Twenty mechanically-ventilated adult patients who received a fluid challenge after cardiac surgery were enrolled. They were regarded as responders if the cardiac index increased more than 15%. Before and after the fluid challenge, IVC anteroposterior (AP) and lateral (LA) diameters, the flat ratio, and the distensibility index were assessed by ultrasound just above the iliac veins, at the confluence of the renal veins, before the confluence of the hepatic veins (where blood flow velocity was also measured), and after it. RESULTS: At all levels, IVC section was elliptical, so that IVC diameters varied between a minimum and a maximum according to the measurement angle. Such interval increased in correspondence of the renal veins, where IVC section was more eccentric. The distensibility index was higher when assessed on AP diameters. After the fluid challenge, non-responders showed a diffuse increase of AP diameters, whereas responders showed an increase of blood velocity before the confluence of the hepatic veins. CONCLUSIONS: The elliptic section should be considered when assessing IVC size. AP diameters are shorter and more affected by the respiratory cycle. After a fluid challenge, an increase of blood velocity associated with unchanged AP diameters may suggest fluid responsiveness.

Targeting zero catheter-related bloodstream infections in pediatric intensive care unit: a retrospective matched case-control study.

INTRODUCTION: The aim of this study was to evaluate the effectiveness and safety of a new three-component 'bundle' for insertion and management of centrally inserted central catheters (CICCs), designed to minimize catheter-related bloodstream infections (CRBSIs) in critically ill children. METHODS: Our 'bundle' has three components: insertion, management, and education. Insertion and management recommendations include: skin antisepsis with 2% chlorhexidine; maximal barrier precautions; ultrasound-guided venipuncture; tunneling of the catheter when a long indwelling time is expected; glue on the exit site; sutureless securement; use of transparent dressing; chlorhexidine sponge dressing on the 7th day; neutral displacement needle-free connectors. All CICCs were inserted by appropriately trained physicians proficient in a standardized simulation training program. RESULTS: We compared CRBSI rate per 1000 catheters-days of CICCs inserted before adoption of our new bundle with that of CICCs inserted after implementation of the bundle. CICCs inserted after adoption of the bundle remained in place for a mean of 2.2 days longer than those inserted before. We found a drop in CRBSI rate to 10%, from 15 per 1000 catheters-days to 1.5. CONCLUSIONS: Our data suggest that a bundle aimed at minimizing CR-BSI in critically ill children should incorporate four practices: (1) ultrasound guidance, which minimizes contamination by reducing the number of attempts and possible break-down of aseptic technique; (2) tunneling the catheter to obtain exit site in the infra-clavicular area with reduced bacterial colonization; (3) glue, which seals and protects the exit site; (4) simulation-based education of the staff.