An analysis of the treatment effect of two modes of oxygenation on patients with radiation pneumonia complicated by respiratory failure

BACKGROUND: Stereotactic radiotherapy (SBRT) is widely used in the treatment of thoracic cancer. OBJECTIVE: To evaluate the efficacy of a non-rebreather mask (NRBM) and high-flow nasal cannula (HFNC) in patients with radiation pneumonia complicated with respiratory failure. METHODS: This was a single-center randomized controlled study. Patients admitted to the EICU of the Fourth Hospital of Hebei Medical University were selected and divided into NRBM and HFNC group. Arterial blood gas analysis, tidal volume, respiratory rates and the cases of patients receiving invasive assisted ventilation were collected at 0, 4, 8, 12, 24, 48, and 72 h after admission. RESULTS: (1) The PaO2/FiO2, respiratory rates, and tidal volume between the two groups at 0, 4, 8, 12, 24, 48, and 72 h were different, with F values of 258.177, 294.121, and 134.372, all P< 0.01. These indicators were different under two modes of oxygenation, with F values of 40.671, 168.742, and 55.353, all P< 0.01, also varied with time, with an F value of 7.480, 9.115, and 12.165, all P< 0.01. (2) The incidence of trachea intubation within 72 h between HFNC and NRBM groups (23 [37.1%] vs. 34 [54.0%], P< 0.05). The transition time to mechanical ventilation in the HFNC and NRBM groups (55.3 ± 3.2 h vs. 45.9 ± 3.6 h, P< 0.05). (3) The risk of intubation in patients with an APACHE-II score > 23 was 2.557 times than score ⩽ 23, and the risk of intubation in the NRBM group was 1.948 times more than the HFNC group (P< 0.05). CONCLUSION: Compared with the NRBM, HFNC can improve the oxygenation state of patients with radiation pneumonia complicated with respiratory failure in a short time, and reduce the incidence of trachea intubation within 72 h.

c-Fos is a mechanosensor that regulates inflammatory responses and lung barrier dysfunction during ventilator-induced acute lung injury

Background As one of the basic treatments performed in the intensive care unit, mechanical ventilation can cause ventilator-induced acute lung injury (VILI). The typical features of VILI are an uncontrolled inflammatory response and impaired lung barrier function; however, its pathogenesis is not fully understood, and c-Fos protein is activated under mechanical stress. c-Fos/activating protein-1 (AP-1) plays a role by binding to AP-1 within the promoter region, which promotes inflammation and apoptosis. T-5224 is a specific inhibitor of c-Fos/AP-1, that controls the gene expression of many proinflammatory cytokines. This study investigated whether T-5224 attenuates VILI in rats by inhibiting inflammation and apoptosis. Methods The SD rats were divided into six groups: a control group, low tidal volume group, high tidal volume group, DMSO group, T-5224 group (low concentration), and T-5224 group (high concentration). After 3 h, the pathological damage, c-Fos protein expression, inflammatory reaction and apoptosis degree of lung tissue in each group were detected. Results c-Fos protein expression was increased within the lung tissue of VILI rats, and the pathological damage degree, inflammatory reaction and apoptosis in the lung tissue of VILI rats were significantly increased; T-5224 inhibited c-Fos protein expression in lung tissues, and T-5224 inhibit the inflammatory reaction and apoptosis of lung tissue by regulating the Fas/Fasl pathway. Conclusions c-Fos is a regulatory factor during ventilator-induced acute lung injury, and the inhibition of its expression has a protective effect. Which is associated with the antiinflammatory and antiapoptotic effects of T-5224.

Disparities in Lung Protective Ventilation in the United States

Background: Lung-protective ventilation is often used in critically ill patients with acute respiratory failure, including those without acute respiratory distress syndrome. While disparities exist in the delivery of critical care based on gender, race, and insurance status, it is unknown whether there are disparities in the use of lung-protective ventilation. The objective of our study was to determine whether gender-, racial / ethnic-, or insurance status-based disparities exist in the use of lung-protective ventilation for critically ill mechanically ventilated patients in the United States (U.S.).Methods: This was a secondary data analysis of the U.S. Critical Illness and Injury Trials Group Critical Illness Outcomes Study, a prospective multi-center cohort study conducted from 2010 - 2012. The dependent variable of interest was the proportion of patients receiving tidal volume > 8 mL/kg predicted body weight (PBW). The independent variables of interest were gender, insurance status, and race / ethnicity. Results: Our primary analysis included 1,595 mechanically ventilated patients from 59 intensive care units (ICUs) in the U.S. Women were more likely to receive tidal volumes > 8 ml/kg PBW than men (odds ratio [OR] = 3.25, 95% confidence interval [CI] = 2.58 – 4.09), though this relationship was substantially weakened after adjusting for gender differences in height (OR = 1.26 95% CI = 0.94 – 1.71). The underinsured were significantly more likely to receive tidal volume > 8 ml/kg PBW than the insured in multivariable analysis (odds ratio = 1.54, 95% confidence interval = 1.16 – 2.04). The prescription of > 8 ml/kg PBW tidal volume did not differ by racial or ethnic categories. Conclusions: In this prospective nationwide cohort of critically ill mechanically ventilated patients, women and the underinsured were less likely than their comparators to receive lung protective ventilation, with no apparent differences based on race / ethnicity alone. Differences in height between men and women do not fully explain this disparity. Future research should evaluate whether implicit bias affects tidal volume choice and other management decisions in critical care.

Hyaluronic acid plasma levels during high versus low tidal volume ventilation in a porcine sepsis model

Background Shedding of the endothelial glycocalyx can be observed regularly during sepsis. Moreover, sepsis may be associated with acute respiratory distress syndrome (ARDS), which requires lung protective ventilation with the two cornerstones of application of low tidal volume and positive end-expiratory pressure. This study investigated the effect of a lung protective ventilation on the integrity of the endothelial glycocalyx in comparison to a high tidal volume ventilation mode in a porcine model of sepsis-induced ARDS. Methods After approval by the State and Institutional Animal Care Committee, 20 male pigs were anesthetized and received a continuous infusion of lipopolysaccharide to induce septic shock. The animals were randomly assigned to either low tidal volume ventilation, high tidal volume ventilation, or no-LPS-group groups and observed for 6 h. In addition to the gas exchange parameters and hematologic analyses, the serum hyaluronic acid concentrations were determined from central venous blood and from pre- and postpulmonary and pre- and postcerebral circulation. Post-mortem analysis included histopathological evaluation and determination of the pulmonary and cerebral wet-to-dry ratios. Results Both sepsis groups developed ARDS within 6 h of the experiment and showed significantly increased serum levels of hyaluronic acid in comparison to the no-LPS-group. No significant differences in the hyaluronic acid concentrations were detected before and after pulmonary and cerebral circulation. There was also no significant difference in the serum hyaluronic acid concentrations between the two sepsis groups. Post-mortem analysis showed no significant difference between the two sepsis groups. Conclusion In a porcine model of septic shock and ARDS, the serum hyaluronic acid levels were significantly elevated in both sepsis groups in comparison to the no-LPS-group. Intergroup comparison between lung protective ventilated and high tidal ventilated animals revealed no significant differences in the serum hyaluronic acid levels.

Tidal Volume in Pediatric Ventilation: Do You Get What You See?

Mechanical ventilators are increasingly evolving into computer-driven devices. These technical advancements have impact on clinical decisions in pediatric intensive care units (PICUs). A good understanding of the design of mechanical ventilators can improve clinical care. Tidal volume (TV) is one of the corner stones of ventilation: multiple technical factors influence the TV and, thus, influence clinical decision making. Ventilator manufacturers make various design choices regarding the phase, site and conditions of TV measurement as well as algorithmic processing choices. Such choice may impact the measurement and subsequent display of TV. A software change of the TV measuring algorithm of the SERVO-i® (Getinge, Solna, Sweden) at the PICU of the University Medical Centre Utrecht was studied in a prospective cohort. It showed, as example, a clinically significant impact of 8% difference in reported TV. Design choices in both the hardware and software of mechanical ventilators can have a clinically relevant impact on the measurement of tidal volume. In our search for the optimal TV for lung-protective ventilation, such choices should be taken into account.

Effect of Trendelenburg position during prone ventilation in fifteen COVID-19 patients. Observational study

Background Prone position ventilation has shown to improve oxygenation and mortality in severe ARDS. The data of prone position ventilation during severe ARDS secondary to COVID-19 have shown similar benefit in oxygenation and mortality. Usually, patient placed in prone position are placed flat or in reverse Trendelenburg positioning to decrease risk of aspiration and abdominal girth compressing the chest. To date, no studies are available to compare the effects of positioning the bed in different angles during the prone position ventilation. Methods An observational study in fifteen patients with severe ARDS secondary to COVID-19 who were placed in the prone position for the first time. All the patients were sedated and chemically paralyzed with no spontaneous effort. All patients were ventilated with the pressure-controlled mode with set PEEP according to the pressure-volume curves. Five patients had esophageal balloon manometry to estimate pleural pressures and trans-pulmonary pressures. Patients were initially placed in reverse Trendelenburg position and later in Trendelenburg position. Tidal volume and respiratory compliance were observed for 30 minutes after bed positioning has been achieved. Tidal volume and total respiratory compliance in both Trendelenburg and reverse Trendelenburg position were compared. Ventilator settings were not changed during the observation. No patients were suspected of increased intra-cranial or intra-ocular pressures. T-test was done to compare the values. Results Tidal volume significantly increased by 80.26 ± 23.4 ml/breath (95% CI 37.7 - 122.9) from 391.3 ± 52.7 to 471.6 ± 60.9 (20.5%) P 0.001. The respiratory system compliance significantly increased by 4.9 ml/cmH2O (95% CI 1.4 - 8.4) from 34.6 ± 4.7 to 39.5 ± 4.6 (14%) P 0.001. Of the five patients with esophageal balloon, the lung compliance significantly increased by 16.7 ml/cmH2O (95% CI 12.8 – 20.6) from 66.6 ± 1.7 to 83.3 ± 3.3 (25%) P 0.001. The chest wall compliance had small but non-significant increase by 1.5 ml/cmH2O (95% CI -1.3 – 4.3) from 65 ± 1.4 to 66.5 ± 2.3 (2%) P 0.085. Conclusion In this study, statistically significant increase in tidal volume, lung and respiratory system compliance were observed in patients placed in the Trendelenburg position during prone position ventilation. The results reflect the effect of body positioning during prone position ventilation. These effects may be the reflection of altered ventilation distribution throughout the lungs and change in pleural pressure as well as trans-pulmonary pressure during body positioning. More studies need to be done to confirm and examine this phenomenon. Precautions should be taken as this maneuver can increase the intra-cranial and intra-ocular pressures. Keywords: COVID-19, Trendelenburg, Reverse Trendelenburg, ARDS

Preclinical Trial of the Effectiveness of the Safety Nasogastric Tube to Detecting Tube Position Based on Tidal Volume and Pepsin Assay Results in the Gastrointestinal Tract of Macaca Fascicularis

Background: Generally, insertion of a nasogastric tube (NGT) does not use imaging guidance. This procedure has a risk of malposition to the lungs from 0.3–15%. The NGT verification only detects the position of the tube in the end of procedure. Misplacement of NGT into the respiratory tract can result in damage to the lungs. Safety nasogastric tube (SNGT) has been created to detect the position of the tube in real-time, simple, and inexpensive. This study aims to prove the effectiveness of the SNGT prototype in Macaca fascicularis. Result: The SNGT with an airbag size of 50% of tidal volume (SNGT 50% TV) had 100% sensitivity and specificity in detecting the position of the tube. While the SNGT with an airbag size of 100% of TV (SNGT 100% TV) has sensitivity of 100% and specificity of 87.5%. There was significant difference between the movement of airbag of SNGT 50% TV and SNGT 100% TV (p ≤ 0.05). However, there was no significant difference between the accuracy of placement of 50% TV SNGT, 100% TV SNGT, and conventional NGT (p > 0.05). The pepsin enzyme has better sensitivity (100%) than pH paper (91.66%) in detecting the end position of tube. Conclusion: SNGT tube has high effectiveness in detecting the position of the tube inside of the respiratory and digestive tracts to prevent misplacement.