scholarly journals Novel analysis of 4DCT imaging quantifies progressive increases in anatomic dead space during mechanical ventilation in mice

2017 ◽  
Vol 123 (3) ◽  
pp. 578-584 ◽  
Author(s):  
Elizabeth H. Kim ◽  
Melissa Preissner ◽  
Richard P. Carnibella ◽  
Chaminda R. Samarage ◽  
Ellen Bennett ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Dead Space ◽  
Imaging Techniques ◽  
Lung Compliance ◽  
Pathological Process ◽  
Positive Pressure ◽  
Forced Oscillation Technique ◽  
The Novel ◽  
Tissue Elastance ◽  
Over Time

Increased dead space is an important prognostic marker in early acute respiratory distress syndrome (ARDS) that correlates with mortality. The cause of increased dead space in ARDS has largely been attributed to increased alveolar dead space due to ventilation/perfusion mismatching and shunt. We sought to determine whether anatomic dead space also increases in response to mechanical ventilation. Mice received intratracheal lipopolysaccharide (LPS) or saline and mechanical ventilation (MV). Four-dimensional computed tomography (4DCT) scans were performed at onset of MV and after 5 h of MV. Detailed measurements of airway volumes and lung tidal volumes were performed using image analysis software. The forced oscillation technique was used to obtain measures of airway resistance, tissue damping, and tissue elastance. The ratio of airway volumes to total tidal volume increased significantly in response to 5 h of mechanical ventilation, regardless of LPS exposure, and airways demonstrated significant variation in volumes over the respiratory cycle. These findings were associated with an increase in tissue elastance (decreased lung compliance) but without changes in tidal volumes. Airway volumes increased over time with exposure to mechanical ventilation without a concomitant increase in tidal volumes. These findings suggest that anatomic dead space fraction increases progressively with exposure to positive pressure ventilation and may represent a pathological process. NEW & NOTEWORTHY We demonstrate that anatomic dead space ventilation increases significantly over time in mice in response to mechanical ventilation. The novel functional lung-imaging techniques applied here yield sensitive measures of airway volumes that may have wide applications.

Effective respiratory system elastance during positive-pressure breathing in supine man

1975 ◽  
Vol 39 (4) ◽  
pp. 541-547 ◽  
Author(s):  
W. T. Josenhans ◽  
T. A. Peacocke ◽  
G. Schaller
Keyword(s):  
Mechanical Ventilation ◽  
Respiratory System ◽  
Spontaneous Breathing ◽  
Lung Compliance ◽  
Abdominal Muscle ◽  
Positive Pressure ◽  
Passive Components ◽  
Mechanically Ventilated ◽  
Airway Opening ◽  
Healthy Males

Two healthy males relaxing supine on a ballistobed were mechanically ventilated at positive end-expiratory pressures (PEEP) from 0 to 19 cmH2O. Pressures at the airway opening, middle esophagus, and stomach were monitored, together with tidal volume (VT) and ballistobed displacement. The effective elastance (i.e., sum of active and passive components) of the respiratory system (E'rs) and its components--abdominal muscle (E'ab), diaphragm (E'di), and rib cage (E'rc)--were calculated. With increasing PEEP, lung compliance increased slightly, E'rc and E'di decreased linearly, and E'ab increased linearly. The combined effective elastance of abdomen and diaphragm (E'ab+di) first decreased and then increased again. The abdomen-diaphragm contribution to VT during mechanical ventilation was approximately half that of spontaneous breathing.

Protective mechanical ventilation does not exacerbate lung function impairment or lung inflammation following influenza A infection

2009 ◽  
Vol 107 (5) ◽  
pp. 1472-1478 ◽  
Author(s):  
Graeme R. Zosky ◽  
Vincenzo Cannizzaro ◽  
Zoltan Hantos ◽  
Peter D. Sly
Keyword(s):  
Mechanical Ventilation ◽  
Lung Injury ◽  
Influenza A ◽  
Airway Resistance ◽  
Inflammatory Cells ◽  
Lung Mechanics ◽  
Forced Oscillation Technique ◽  
Protective Ventilation Strategy ◽  
Protective Mechanical Ventilation ◽  
Tissue Elastance

The degree to which mechanical ventilation induces ventilator-associated lung injury is dependent on the initial acute lung injury (ALI). Viral-induced ALI is poorly studied, and this study aimed to determine whether ALI induced by a clinically relevant infection is exacerbated by protective mechanical ventilation. Adult female BALB/c mice were inoculated with 104.5 plaque-forming units of influenza A/Mem/1/71 in 50 μl of medium or medium alone. This study used a protective ventilation strategy, whereby mice were anesthetized, tracheostomized, and mechanically ventilated for 2 h. Lung mechanics were measured periodically throughout the ventilation period using a modification of the forced oscillation technique to obtain measures of airway resistance and coefficients of tissue damping and tissue elastance. Thoracic gas volume was measured and used to obtain specific airway resistance, tissue damping, and tissue elastance. At the end of the ventilation period, a bronchoalveolar lavage sample was collected to measure inflammatory cells, macrophage inflammatory protein-2, IL-6, TNF-α, and protein leak. Influenza infection caused significant increases in inflammatory cells, protein leak, and deterioration in lung mechanics that were not exacerbated by mechanical ventilation, in contrast to previous studies using bacterial and mouse-specific viral infection. This study highlighted the importance of type and severity of lung injury in determining outcome following mechanical ventilation.

scholarly journals Respiratory Modalities in Preventing Reintubation in a Pediatric Intensive Care Unit

2021 ◽  
Vol 8 ◽  
pp. 2333794X2199153
Author(s):  
Ameer Al-Hadidi ◽  
Morta Lapkus ◽  
Patrick Karabon ◽  
Begum Akay ◽  
Paras Khandhar
Keyword(s):  
Intensive Care Unit ◽  
Mechanical Ventilation ◽  
Intensive Care ◽  
Pediatric Intensive Care Unit ◽  
Noninvasive Positive Pressure Ventilation ◽  
Pediatric Intensive Care ◽  
Nasal Cannula ◽  
Respiratory Support ◽  
Positive Pressure ◽  
P Value

Post-extubation respiratory failure requiring reintubation in a Pediatric Intensive Care Unit (PICU) results in significant morbidity. Data in the pediatric population comparing various therapeutic respiratory modalities for avoiding reintubation is lacking. Our objective was to compare therapeutic respiratory modalities following extubation from mechanical ventilation. About 491 children admitted to a single-center PICU requiring mechanical ventilation from January 2010 through December 2017 were retrospectively reviewed. Therapeutic respiratory support assisted in avoiding reintubation in the majority of patients initially extubated to room air or nasal cannula with high-flow nasal cannula (80%) or noninvasive positive pressure ventilation (100%). Patients requiring therapeutic respiratory support had longer PICU LOS (10.92 vs 6.91 days, P-value = .0357) and hospital LOS (16.43 vs 10.20 days, P-value = .0250). Therapeutic respiratory support following extubation can assist in avoiding reintubation. Those who required therapeutic respiratory support experienced a significantly longer PICU and hospital LOS. Further prospective clinical trials are warranted.

scholarly journals Respiratory mechanics and gas exchanges in the early course of COVID-19 ARDS: a hypothesis-generating study

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
J.-L. Diehl ◽  
N. Peron ◽  
R. Chocron ◽  
B. Debuc ◽  
E. Guerot ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Dead Space ◽  
Respiratory Mechanics ◽  
Invasive Mechanical Ventilation ◽  
Endothelial Damage ◽  
Circulating Endothelial Cells ◽  
Pulmonary Mechanics ◽  
High Peep ◽  
Gas Exchanges ◽  
Physiological Dead Space

Abstract Rationale COVID-19 ARDS could differ from typical forms of the syndrome. Objective Pulmonary microvascular injury and thrombosis are increasingly reported as constitutive features of COVID-19 respiratory failure. Our aim was to study pulmonary mechanics and gas exchanges in COVID-2019 ARDS patients studied early after initiating protective invasive mechanical ventilation, seeking after corresponding pathophysiological and biological characteristics. Methods Between March 22 and March 30, 2020 respiratory mechanics, gas exchanges, circulating endothelial cells (CEC) as markers of endothelial damage, and D-dimers were studied in 22 moderate-to-severe COVID-19 ARDS patients, 1 [1–4] day after intubation (median [IQR]). Measurements and main results Thirteen moderate and 9 severe COVID-19 ARDS patients were studied after initiation of high PEEP protective mechanical ventilation. We observed moderately decreased respiratory system compliance: 39.5 [33.1–44.7] mL/cmH2O and end-expiratory lung volume: 2100 [1721–2434] mL. Gas exchanges were characterized by hypercapnia 55 [44–62] mmHg, high physiological dead-space (VD/VT): 75 [69–85.5] % and ventilatory ratio (VR): 2.9 [2.2–3.4]. VD/VT and VR were significantly correlated: r2 = 0.24, p = 0.014. No pulmonary embolism was suspected at the time of measurements. CECs and D-dimers were elevated as compared to normal values: 24 [12–46] cells per mL and 1483 [999–2217] ng/mL, respectively. Conclusions We observed early in the course of COVID-19 ARDS high VD/VT in association with biological markers of endothelial damage and thrombosis. High VD/VT can be explained by high PEEP settings and added instrumental dead space, with a possible associated role of COVID-19-triggered pulmonary microvascular endothelial damage and microthrombotic process.

scholarly journals The Impact of Intervention-Related Risk Factors on the Risk of Ventilator-Associated Pneumonia Is High in a Neurosurgical Intensive Care Unit

2020 ◽  
Vol 41 (S1) ◽  
pp. s407-s409
Author(s):  
Ksenia Ershova ◽  
Oleg Khomenko ◽  
Olga Ershova ◽  
Ivan Savin ◽  
Natalia Kurdumova ◽  
...  
Keyword(s):  
Risk Factors ◽  
Mechanical Ventilation ◽  
Negative Slope ◽  
Infection Prevention And Control ◽  
Ventilator Associated Pneumonia ◽  
Related Factors ◽  
Icu Patients ◽  
The Impact ◽  
Adf Test ◽  
Over Time

Background: Ventilator-associated pneumonia (VAP) represents the highest burden among all healthcare-associated infections (HAIs), with a particularly high rate in patients in neurosurgical ICUs. Numerous VAP risk factors have been identified to provide a basis for preventive measures. However, the impact of individual factors on the risk of VAP is unclear. The goal of this study was to evaluate the dynamics of various VAP risk factors given the continuously declining prevalence of VAP in our neurosurgical ICU. Methods: This prospective cohort unit-based study included neurosurgical patients who stayed in the ICU >48 consecutive hours in 2011 through 2018. The infection prevention and control (IPC) program was implemented in 2010 and underwent changes to adopt best practices over time. We used a 2008 CDC definition for VAP. The dynamics of VAP risk factors was considered a time series and was checked for stationarity using theAugmented Dickey-Fuller test (ADF) test. The data were censored when a risk factor was present during and after VAP episodes. Results: In total, 2,957 ICU patients were included in the study, 476 of whom had VAP. Average annual prevalence of VAP decreased from 15.8 per 100 ICU patients in 2011 to 9.5 per 100 ICU patients in 2018 (Welch t test P value = 7.7e-16). The fitted linear model showed negative slope (Fig. 1). During a study period we observed substantial changes in some risk factors and no changes in others. Namely, we detected a decrease in the use of anxiolytics and antibiotics, decreased days on mechanical ventilation, and a lower rate of intestinal dysfunction, all of which were nonstationary processes with a declining trend (ADF testP > .05) (Fig. 2). However, there were no changes over time in such factors as average age, comorbidity index, level of consciousness, gender, and proportion of patients with brain trauma (Fig. 2). Conclusions: Our evidence-based IPC program was effective in lowering the prevalence of VAP and demonstrated which individual measures contributed to this improvement. By following the dynamics of known VAP risk factors over time, we found that their association with declining VAP prevalence varies significantly. Intervention-related factors (ie, use of antibiotics, anxiolytics and mechanical ventilation, and a rate of intestinal dysfunction) demonstrated significant reduction, and patient-related factors (ie, age, sex, comorbidity, etc) remained unchanged. Thus, according to the discriminative model, the intervention-related factors contributed more to the overall risk of VAP than did patient-related factors, and their reduction was associated with a decrease in VAP prevalence in our neurosurgical ICU.Funding: NoneDisclosures: None

scholarly journals Full-length transcriptome analysis reveals the mechanism of acupuncture at PC6 improves cardiac function in myocardial ischemia model

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Jing Yuan ◽  
Jun-Meng Wang ◽  
Zhi-Wei Li ◽  
Cheng-Shun Zhang ◽  
Bin Cheng ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Cardiac Function ◽  
Acupuncture Treatment ◽  
Pathological Process ◽  
Full Length ◽  
The Novel ◽  
New Genes ◽  
Myocardial Infraction ◽  
Differential Expression Genes ◽  
Multi Level

Abstract Background The pathological process of myocardial ischemia (MI) is very complicated. Acupuncture at PC6 has been proved to be effective against MI injury, but the mechanism remains unclear. This study investigated the mechanism that underlies the effect of acupuncture on MI through full-length transcriptome. Methods Adult male C57/BL6 mice were randomly divided into control, MI, and PC6 groups. Mice in MI and PC6 group generated MI model by ligating the left anterior descending (LAD) coronary artery. The samples were collected 5 days after acupuncture treatment. Results The results showed that treatment by acupuncture improved cardiac function, decreased myocardial infraction area, and reduced the levels of cTnT and cTnI. Based on full-length transcriptome sequencing, 5083 differential expression genes (DEGs) and 324 DEGs were identified in the MI group and PC6 group, respectively. These genes regulated by acupuncture were mainly enriched in the inflammatory response pathway. Alternative splicing (AS) is a post-transcriptional action that contributes to the diversity of protein. In all samples, 8237 AS events associated with 1994 genes were found. Some differential AS-involved genes were enriched in the pathway related to heart disease. We also identified 602 new genes, 4 of which may the novel targets of acupuncture in MI. Conclusions Our findings suggest that the effect of acupuncture on MI may be based on the multi-level regulation of the transcriptome.

scholarly journals Monitoring urinary collagen metabolite changes following collagen peptide ingestion and physical activity using ELISA with anti active collagen oligopeptide antibody

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yoshihiro Osawa ◽  
Kaho Nomura ◽  
Yoshifumi Kimira ◽  
Seiji Kushibe ◽  
Ken-ichi Takeyama ◽  
...  
Keyword(s):  
Physical Activity ◽  
Student Athletes ◽  
Cross Reactivity ◽  
University Student ◽  
Collagen Metabolism ◽  
The Novel ◽  
Urinary Level ◽  
Collagen Peptide ◽  
Urinary Levels ◽  
Over Time

AbstractActive collagen oligopeptides (ACOP) are bioactive collagen-derived peptides detected by a recently-established ELISA. To facilitate studies of the function and metabolism of these products, this study aims to determine which of these peptides is recognized by a novel anti-ACOP antibody used in this ELISA. We then investigate the effect of collagen peptide (CP) ingestion and exercise on urinary ACOP concentrations in a cohort of university student athletes using colorimetric, LC–MS/MS, and ELISA. We observed that the antibody showed strong cross-reactivity to Pro-Hyp and Gly-Pro-Hyp and weak cross-reactivity to commercial CP. CP ingestion increased the urinary level of ACOP over time, which correlated highly with urinary levels of peptide forms of Hyp and Pro-Hyp. Physical activity significantly decreased the urinary ACOP level. This study demonstrates changes in urinary ACOP following oral CP intake and physical activity using ELISA with the novel anti-ACOP antibody. Thus, ACOP may be useful as a new biomarker for collagen metabolism.

scholarly journals Surgical tracheostomy in a cohort of COVID-19 patients

HNO ◽  
2021 ◽  
Author(s):  
Patrick J. Schuler ◽  
Jens Greve ◽  
Thomas K. Hoffmann ◽  
Janina Hahn ◽  
Felix Boehm ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Respiratory Failure ◽  
Prolonged Mechanical Ventilation ◽  
Tertiary Care ◽  
Lung Compliance ◽  
Hypoxemic Respiratory Failure ◽  
Surgical Tracheostomy ◽  
Increased Risk ◽  
Open Surgical Tracheostomy ◽  
Sedative Drugs

Abstract Background One of the main symptoms of severe infection with the new coronavirus‑2 (SARS-CoV-2) is hypoxemic respiratory failure because of viral pneumonia with the need for mechanical ventilation. Prolonged mechanical ventilation may require a tracheostomy, but the increased risk for contamination is a matter of considerable debate. Objective Evaluation of safety and effects of surgical tracheostomy on ventilation parameters and outcome in patients with COVID-19. Study design Retrospective observational study between March 27 and May 18, 2020, in a single-center coronavirus disease-designated ICU at a tertiary care German hospital. Patients Patients with COVID-19 were treated with open surgical tracheostomy due to severe hypoxemic respiratory failure requiring mechanical ventilation. Measurements Clinical and ventilation data were obtained from medical records in a retrospective manner. Results A total of 18 patients with confirmed SARS-CoV‑2 infection and surgical tracheostomy were analyzed. The age range was 42–87 years. All patients received open tracheostomy between 2–16 days after admission. Ventilation after tracheostomy was less invasive (reduction in PEAK and positive end-expiratory pressure [PEEP]) and lung compliance increased over time after tracheostomy. Also, sedative drugs could be reduced, and patients had a reduced need of norepinephrine to maintain hemodynamic stability. Six of 18 patients died. All surgical staff were equipped with N99-masks and facial shields or with powered air-purifying respirators (PAPR). Conclusion Our data suggest that open surgical tracheostomy can be performed without severe complications in patients with COVID-19. Tracheostomy may reduce invasiveness of mechanical ventilation and the need for sedative drugs and norepinehprine. Recommendations for personal protective equipment (PPE) for surgical staff should be followed when PPE is available to avoid contamination of the personnel.

scholarly journals Oxygen administration for patients with ARDS

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Shinichiro Ohshimo
Keyword(s):  
Mechanical Ventilation ◽  
Lung Injury ◽  
Positive Pressure ◽  
Respiratory Drive ◽  
Severe Hypoxemia ◽  
Airway Occlusion ◽  
Non Invasive ◽  
Oxygen Administration ◽  
Essential Interventions ◽  
Invasive Techniques

AbstractAcute respiratory distress syndrome (ARDS) is a fatal condition with insufficiently clarified etiology. Supportive care for severe hypoxemia remains the mainstay of essential interventions for ARDS. In recent years, adequate ventilation to prevent ventilator-induced lung injury (VILI) and patient self-inflicted lung injury (P-SILI) as well as lung-protective mechanical ventilation has an increasing attention in ARDS.Ventilation-perfusion mismatch may augment severe hypoxemia and inspiratory drive and consequently induce P-SILI. Respiratory drive and effort must also be carefully monitored to prevent P-SILI. Airway occlusion pressure (P0.1) and airway pressure deflection during an end-expiratory airway occlusion (Pocc) could be easy indicators to evaluate the respiratory drive and effort. Patient-ventilator dyssynchrony is a time mismatching between patient’s effort and ventilator drive. Although it is frequently unrecognized, dyssynchrony can be associated with poor clinical outcomes. Dyssynchrony includes trigger asynchrony, cycling asynchrony, and flow delivery mismatch. Ventilator-induced diaphragm dysfunction (VIDD) is a form of iatrogenic injury from inadequate use of mechanical ventilation. Excessive spontaneous breathing can lead to P-SILI, while excessive rest can lead to VIDD. Optimal balance between these two manifestations is probably associated with the etiology and severity of the underlying pulmonary disease.High-flow nasal cannula (HFNC) and non-invasive positive pressure ventilation (NPPV) are non-invasive techniques for supporting hypoxemia. While they are beneficial as respiratory supports in mild ARDS, there can be a risk of delaying needed intubation. Mechanical ventilation and ECMO are applied for more severe ARDS. However, as with HFNC/NPPV, inappropriate assessment of breathing workload potentially has a risk of delaying the timing of shifting from ventilator to ECMO. Various methods of oxygen administration in ARDS are important. However, it is also important to evaluate whether they adequately reduce the breathing workload and help to improve ARDS.

Comparative study between noninvasive positive pressure ventilation and invasive mechanical ventilation in patients with respiratory failure

QJM ◽  
2021 ◽  
Vol 114 (Supplement_1) ◽  
Author(s):  
Mohammed N Al Shafi'i ◽  
Doaa M. Kamal El-din ◽  
Mohammed A. Abdulnaiem Ismaiel ◽  
Hesham M Abotiba
Keyword(s):  
Intensive Care Unit ◽  
Mechanical Ventilation ◽  
Intensive Care ◽  
Respiratory Failure ◽  
Acute Respiratory Failure ◽  
Positive Pressure Ventilation ◽  
Invasive Mechanical Ventilation ◽  
Noninvasive Positive Pressure Ventilation ◽  
Positive Pressure ◽  
Significant Difference

Abstract Background Noninvasive positive pressure ventilation (NIPPV) has been increasingly used in the management of respiratory failure in intensive care unit (ICU). Aim of the Work is to compare the efficacy and resource consumption of NIPPMV delivered through face mask against invasive mechanical ventilation (IMV) delivered by endotracheal tube in the management of patients with acute respiratory failure (ARF). Patients and Methods This prospective randomized controlled study included 78 adults with acute respiratory failure who were admitted to the intensive care unit. The enrolled patients were randomly allocated to receive either noninvasive ventilation or conventional mechanical ventilation (CMV). Results Severity of illness, measured by the simplified acute physiologic score 3 (SAPS 3), were comparable between the two patient groups with no significant difference between them. Both study groups showed a comparable steady improvement in PaO2:FiO2 values, indicating that NIPPV is as effective as CMV in improving the oxygenation of patients with ARF. The PaCO2 and pH values gradually improved in both groups during the 48 hours of ventilation. 12 hours after ventilation, NIPPMV group showed significantly more improvement in PaCO2 and pH than the CMV group. The respiratory acidosis was corrected in the NIPPV group after 24 hours of ventilation compared with 36 hours in the CMV group. NIPPV in this study was associated with a lower frequency of complications than CMV, including ventilator acquired pneumonia (VAP), sepsis, renal failure, pulmonary embolism, and pancreatitis. However, only VAP showed a statistically significant difference. Patients who underwent NIPPV in this study had lower mortality, and lower ventilation time and length of ICU stay, compared with patients on CMV. Intubation was required for less than a third of patients who initially underwent NIV. Conclusion Based on our study findings, NIPPV appears to be a potentially effective and safe therapeutic modality for managing patients with ARF.

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