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Perfluorocarbons (PFCs) are organic liquids derived from hydrocarbons in which some of the hydrogen atoms have been replaced by fluorine atoms.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.

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.

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.

Validation of the Glycemic Stress Index in Pediatric Neurosurgical Intensive Care.

BACKGROUND: Studies have suggested that both the degree and the duration of hyperglycemia are independent risk factors for adverse outcome both in pediatric anesthesia and in critically ill children. In a recent paper, we combined intraoperative glycemic variations and length of surgery creating a metabolic glucose-related stress index called "Glycemic Stress Index" (GSI). AIM: To validate GSI for predicting PICU stay in a population of children undergoing different major neurosurgical procedures. METHODS: A total of 352 patients with craniotomy were enrolled. Basic clinical data and PICU length of stay were recorded real time. Intraoperative blood loss has been determined considering the estimated red cell volume loss ratio. GSI was calculated and subjected to ROC analysis having as targets PICU length of stay >100 or >200 h. RESULTS: The overall mean PICU stay was 35 h. Correlation analysis confirmed a low but highly significant direct correlation between GSI and PICU length of stay. ROC analysis showed an area under the ROC curve (AUC) of 0.74 (p = 0.03) for GSI to predict PICU stay >200 h and an AUC of 0.67 (p = 0.01) to predict PICU stay >100 h. Best predictive cutoff values were 4.5 and 3.9, for PICU stay >200 and >100 h, respectively. Overall accuracy for the test is higher in predicting PICU stay >200 h. CONCLUSIONS: GSI significantly predicts prolonged PICU stay after major neurosurgery in a mixed population of children affected by different neurosurgical conditions.

Point-of-care pleural and lung ultrasound in a newborn suffering from cardiac arrest due to tension pneumothorax after cardiac surgery.

We report the case of a 12-day-old newborn affected by coarctation of the aorta and intraventricular defect who underwent coarctectomy and pulmonary artery banding. On post-operative day 7, the patient suffered from pulseless electric activity due to tension pneumothorax. Point-of-care ultrasound was performed during cardiopulmonary resuscitation in an attempt to diagnose pneumothorax. The diagnosis was made without delaying or interrupting chest compressions, and the pneumothorax was promptly treated.

Sonographic dynamic assessment of lung injury in a child with hypoplastic left heart syndrome undergoing extracorporeal membrane oxygenation.

INTRODUCTION: Performed for many years in clinical settings, pleural and lung ultrasound (PLUS) has emerged to be an invaluable tool to diagnose underlying conditions of respiratory failure, to monitor disease progression and to ensure appropriate therapeutic intervention. PLUS basically relies on the analysis of two prevalent ultrasound artefacts: A-lines and B-lines. A-lines are hyperechoic reverberation artefacts of the pleural line. A-lines combined with lung sliding show that lungs are well aerated. B-lines are vertical hyperechoic reverberation artefacts arising from pleural line extending to the bottom of the screen. The prevalence of B-lines indicates a pathologic parenchyma. Since PLUS is readily available, easily affordable, and biologically non-invasive, it is especially suitable for bedside clinical care in critically ill and unstable adult patients. Several authors have recently proposed PLUS for application in critically ill neonates and children. We report a case in which PLUS was used to clinically monitor a complex lung lesion during treatment of a child with congenital heart disease suffering from severe lung injury. CASE DESCRIPTION: A 1-year-old male with hypoplastic left heart syndrome underwent bidirectional Glenn procedure and systemic-to-left pulmonary artery shunt for heart palliation. After surgery, he developed a severe acute respiratory distress syndrome (ARDS) and extra-corporeal membrane oxygenation (ECMO) treatment was started. PLUS was performed daily to monitor the disease's progression and response to treatment during lung rest. As B-lines were decreasing and A-lines were becoming visible, we were able to monitor the improving aeration of the injured lung. The ultrasound showed high consistency with traditional imaging. DISCUSSION: Due to its non-ionizing nature, low cost, easy availability, easy repeatability and real-time results, PLUS is a feasible and beneficial bedside imaging technique for critically ill and unstable adult and pediatric patients. A reliable monitoring of ongoing treatments is certainly helpful to provide appropriate intervention, correctly schedule chest X-ray and CT-scan, and optimize ECMO weaning. The present case suggests that PLUS may be a successful and useful tool for monitoring lung diseases in children with CHD with severe post-operative complex lung injury.