Treatment Volume, Dose Prescription and Delivery Techniques for Dose-intensification in Rectal Cancer: A National Survey.

BACKGROUND/AIM: The aim of the study was to investigate boost volume definition, doses, and delivery techniques for rectal cancer dose intensification. PATIENTS AND METHODS: An online survey was made on 25 items (characteristics, simulation, imaging, volumes, doses, planning and treatment). RESULTS: Thirty-eight radiation oncologists joined the study. Twenty-one delivered long-course radiotherapy with dose intensification. Boost volume was delineated on diagnostic magnetic resonance imaging (MRI) in 18 centres (85.7%), and computed tomography (CT) and/or positron emission tomography-CT in 9 (42.8%); 16 centres (76.2%) performed co-registration with CT-simulation. Boost dose was delivered on gross tumor volume in 10 centres (47.6%) and on clinical target volume in 11 (52.4%). The most common total dose was 54-55 Gy (71.4%), with moderate hypofractionation (85.7%). Intensity-modulated radiotherapy (IMRT) was used in all centres, with simultaneous integrated boost in 17 (80.8%) and image-guidance in 18 (85.7%). CONCLUSION: A high quality of treatment using dose escalation can be inferred by widespread multidisciplinary discussion, MRI-based treatment volume delineation, and radiation delivery relying on IMRT with accurate image-guided radiation therapy protocols.

Effect of Driving Pressure Change During Extracorporeal Membrane Oxygenation in Adults With Acute Respiratory Distress Syndrome: A Randomized Crossover Physiologic Study.

OBJECTIVES: Venovenous extracorporeal membrane oxygenation is an effective intervention to improve gas exchange in patients with severe acute respiratory distress syndrome. However, the mortality of patients with severe acute respiratory distress syndrome supported with venovenous extracorporeal membrane oxygenation remains high, and this may be due in part to a lack of standardized mechanical ventilation strategies aimed at further minimizing ventilator-induced lung injury. We tested whether a continuous positive airway pressure ventilation strategy mitigates ventilator-induced lung injury in patients with severe acute respiratory distress syndrome on venovenous extracorporeal membrane oxygenation, compared with current ventilation practice that employs tidal ventilation with limited driving pressure. We used plasma biomarkers as a surrogate outcome for ventilator-induced lung injury. DESIGN: Randomized crossover physiologic study. SETTING: Single-center ICU. PATIENTS: Ten patients with severe acute respiratory distress syndrome supported on venovenous extracorporeal membrane oxygenation. INTERVENTIONS: The study included four phases. After receiving pressure-controlled ventilation with driving pressure of 10 cm H2O for 1 hour (phase 1), patients were randomly assigned to receive first either pressure-controlled ventilation 20 cm H2O for 2 hours (phase 2) or continuous positive airway pressure for 2 hours (phase 3), and then crossover to the other phase for 2 hours; during phase 4 ventilation settings returned to baseline (pressure-controlled ventilation 10 cm H2O) for 4 hours. MEASUREMENTS AND MAIN RESULTS: There was a linear relationship between the change in driving pressure and the plasma concentration of interleukin-6, soluble receptor for advanced glycation end products, interleukin-1ra, tumor necrosis factor alpha, surfactant protein D, and interleukin-10. CONCLUSIONS: Ventilator-induced lung injury may occur in acute respiratory distress syndrome patients on venovenous extracorporeal membrane oxygenation despite the delivery of volume- and pressure-limited mechanical ventilation. Reducing driving pressure to zero may provide more protective mechanical ventilation in acute respiratory distress syndrome patients supported with venovenous extracorporeal membrane oxygenation. However, the risks versus benefits of such an approach need to be confirmed in studies that are designed to test patient centered outcomes.

Pulse contour analysis of arterial waveform in a high fidelity human patient simulator.

The measurement of cardiac output (CO) may be useful to improve the assessment of hemodynamics during simulated scenarios. The purpose of this study was to evaluate the feasibility of introducing an uncalibrated pulse contour device (MostCare, Vytech, Vygon, Padova, Italy) into the simulation environment. MostCare device was plugged to a clinical monitor and connected to the METI human patient simulator (HPS) to obtain a continuous arterial waveform analysis and CO calculation. In six different simulated clinical scenarios (baseline, ventricular failure, vasoplegic shock, hypertensive crisis, hypovolemic shock and aortic stenosis), the HPS-CO and the MostCare-CO were simultaneously recorded. The level of concordance between the two methods was assessed by the Bland and Altman analysis. 150-paired CO values were obtained. The HPS-CO values ranged from 2.3 to 6.6 L min-1 and the MostCare-CO values from 2.8 to 6.4 L min-1. The mean difference between HPS-CO and MostCare-CO was - 0.3 L min-1 and the limits of agreement were - 1.5 and 0.9 L min-1. The percentage of error was 23%. A good correlation between HPS-CO and MostCare-CO was observed in each scenario of the study (r = 0.88). Although MostCare-CO tended to underestimate the CO over the study period, good agreements were found between the two methods. Therefore, a pulse contour device can be integrated into the simulation environment, offering the opportunity to create new simulated clinical settings.

Airway Pressure Release Ventilation and High-Frequency Oscillatory Ventilation: Potential Strategies to Treat Severe Hypoxemia and Prevent Ventilator-Induced Lung Injury.

Although lifesaving, mechanical ventilation can itself be responsible for damage to lung parenchyma. This ventilator-induced lung injury is especially observed in already injured lungs of patients with ARDS. New ventilatory approaches are needed to safely treat patients with ARDS, and recent studies have suggested the potential utility of open-lung strategies. Airway pressure release ventilation (APRV) and high-frequency oscillatory ventilation (HFOV) are 2 different open-lung strategies that have been proposed to treat refractory hypoxemic respiratory failure while preventing ventilator-induced lung injury. APRV provides increased airway pressure as a potential recruitment mechanism and allows spontaneous breathing, with the potential benefits of decreased sedation, shorter duration of mechanical ventilation, and improvement in cardiac performance. HFOV delivers very small tidal volumes, to prevent volutrauma, at a constant (relatively high) mean airway pressure, thus avoiding atelectrauma. Despite their theoretical benefits, the utility of APRV and HFOV remains unproven and controversial for the routine treatment of ARDS in adult patients. This review is focused on the theoretical and practical aspects of APRV and HFOV, provides an overview of the current evidence, and addresses their possible use in the treatment of ARDS.

Cell growth modulation of human cells irradiated in vitro with low-level laser therapy.

OBJECTIVE: The aim of this study was to investigate the effects of different wavelengths and doses of laser radiation on in vitro cell proliferation. We evaluated the biological effects of low-level laser therapy (LLLT) on two human cancer cell lines: HeLa (epithelial adenocarcinoma) and TK6 (lymphoblast). Our attention was focused on the combination of the two laser emissions as it could have a synergic effect greater than the single emission applied separately. BACKGROUND DATA: The effects of LLLT on human cells are still poorly understood and unexplained. Several cell types were found non responsive to laser bio stimulation; in other cases, only a partial activation was observed. METHODS: A laser device was used for cell irradiation with a continuous wave diode (lambda = 808 nm), a pulsed wave diode (lambda = 905 nm), and a combined wave diodes (lambda = 808 nm + 905 nm), in the dose range of 1-60 J/cm(2). RESULTS: The effect of the combined low-level 808-905-nm diode laser irradiation were slightly superior to those achieved with either laser alone in HeLa cells. TK6 cellular proliferation was not found to be significantly affected by any of the energy levels and varying exposure doses investigated. CONCLUSIONS: Our results are a confirmation of previous observations carried out on human cells, where only the proliferation of slowly growing cell populations appeared to be stimulated by laser light.