scholarly journals Methods to Evaluate Airway Resistance and Lung Compliance During Mechanical Ventilation: A Comparative Study

2020 ◽  
Vol 5 (7) ◽  
pp. 947-951
Author(s):  
Apoorva S Kulkarni ◽  
Sheela N
Keyword(s):  
Mechanical Ventilation ◽  
Respiratory System ◽  
Airway Resistance ◽  
Lung Compliance ◽  
Accurate Estimate ◽  
Least Square ◽  
Dynamic Approach ◽  
System Equation ◽  
Respiratory Parameters ◽  
Lung Condition

Mechanical ventilation is a lifesaving activity that is used in critical care management. In such case, monitoring of airway resistance(Raw) and lung compliance(CL) play a major role for diagnosing the lung condition, setting the ventilator parameters, can act as a decision parameter for weaning the patient from the ventilator. Several methods have been described for estimating these respiratory parameters. In this work, a study is conducted to compare two different methods used to calculate airway resistance and lung compliance during mechanical ventilation. Michigan Adult/Infant lung simulator is used to simulate different compliance conditions and Michigan Pneuflo Resistors to simulate different resistance conditions. Flow, volume and pressure data were logged for different set parameters i.e. for different resistance and compliance combinations. Later these data were used to calculate the respiratory system resistance and compliance. Two methods were used to calculate lung parameters, dynamic approach and Least Square fitting(LSF) method(using respiratory system equation of motion). Both methods gave accurate estimate of Raw and CL. But the dynamic approach required respiratory maneuver whereas LSF approach required large datasets to carry out the calculation and the patient should not show any active breathing during evaluation

scholarly journals Energy transmission in mechanically ventilated children: a translational study

Critical Care ◽  
2020 ◽  
Vol 24 (1) ◽  
Author(s):  
Martin C. J. Kneyber ◽  
Stavroula Ilia ◽  
Alette A. Koopman ◽  
Patrick van Schelven ◽  
Jefta van Dijk ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Lung Injury ◽  
Endotracheal Tube ◽  
Respiratory System ◽  
Airway Resistance ◽  
Mechanical Energy ◽  
Laboratory Data ◽  
Lung Compliance ◽  
Lung Pathology ◽  
Mechanically Ventilated

Abstract Background Recurrent delivery of tidal mechanical energy (ME) inflicts ventilator-induced lung injury (VILI) when stress and strain exceed the limits of tissue tolerance. Mechanical power (MP) is the mathematical description of the ME delivered to the respiratory system over time. It is unknown how ME relates to underlying lung pathology and outcome in mechanically ventilated children. We therefore tested the hypothesis that ME per breath with tidal volume (Vt) normalized to bodyweight correlates with underlying lung pathology and to study the effect of resistance on the ME dissipated to the lung. Methods We analyzed routinely collected demographic, physiological, and laboratory data from deeply sedated and/or paralyzed children < 18 years with and without lung injury. Patients were stratified into respiratory system mechanic subgroups according to the Pediatric Mechanical Ventilation Consensus Conference (PEMVECC) definition. The association between MP, ME, lung pathology, and duration of mechanical ventilation as a primary outcome measure was analyzed adjusting for confounding variables and effect modifiers. The effect of endotracheal tube diameter (ETT) and airway resistance on energy dissipation to the lung was analyzed in a bench model with different lung compliance settings. Results Data of 312 patients with a median age of 7.8 (1.7–44.2) months was analyzed. Age (p <  0.001), RR p <  0.001), and Vt <  0.001) were independently associated with MPrs. ME but not MP correlated significantly (p <  0.001) better with lung pathology. Competing risk regression analysis adjusting for PRISM III 24 h score and PEMVECC stratification showed that ME on day 1 or day 2 of MV but not MP was independently associated with the duration of mechanical ventilation. About 33% of all energy generated by the ventilator was transferred to the lung and highly dependent on lung compliance and airway resistance but not on endotracheal tube size (ETT) during pressure control (PC) ventilation. Conclusions ME better related to underlying lung pathology and patient outcome than MP. The delivery of generated energy to the lung was not dependent on ETT size during PC ventilation. Further studies are needed to identify injurious MErs thresholds in ventilated children.

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.

scholarly journals Goal-Directed Mechanical Ventilation: Are We Aiming at the Right Goals? A Proposal for an Alternative Approach Aiming at Optimal Lung Compliance, Guided by Esophageal Pressure in Acute Respiratory Failure

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Arie Soroksky ◽  
Antonio Esquinas
Keyword(s):  
Mechanical Ventilation ◽  
Respiratory Failure ◽  
Acute Respiratory Failure ◽  
Chest Wall ◽  
Respiratory System ◽  
Transpulmonary Pressure ◽  
Esophageal Pressure ◽  
Plateau Pressure ◽  
Lung Compliance ◽  
Inspiratory Pressure

Patients with acute respiratory failure and decreased respiratory system compliance due to ARDS frequently present a formidable challenge. These patients are often subjected to high inspiratory pressure, and in severe cases in order to improve oxygenation and preserve life, we may need to resort to unconventional measures. The currently accepted ARDSNet guidelines are characterized by a generalized approach in which an algorithm for PEEP application and limited plateau pressure are applied to all mechanically ventilated patients. These guidelines do not make any distinction between patients, who may have different chest wall mechanics with diverse pathologies and different mechanical properties of their respiratory system. The ability of assessing pleural pressure by measuring esophageal pressure allows us to partition the respiratory system into its main components of lungs and chest wall. Thus, identifying the dominant factor affecting respiratory system may better direct and optimize mechanical ventilation. Instead of limiting inspiratory pressure by plateau pressure, PEEP and inspiratory pressure adjustment would be individualized specifically for each patient's lung compliance as indicated by transpulmonary pressure. The main goal of this approach is to specifically target transpulmonary pressure instead of plateau pressure, and therefore achieve the best lung compliance with the least transpulmonary pressure possible.

Using Pressure-Limited Mechanical Ventilation in Caring for Organ Donors

2001 ◽  
Vol 11 (3) ◽  
pp. 174-181 ◽  
Author(s):  
David J. Powner ◽  
Edgar Delgado
Keyword(s):  
Intensive Care Unit ◽  
Mechanical Ventilation ◽  
Intensive Care ◽  
Lung Disease ◽  
Airway Resistance ◽  
Organ Procurement ◽  
Lung Compliance ◽  
Organ Donors ◽  
Permissive Hypercapnia ◽  
Controlled Ventilation

Pressure-limited (controlled) ventilation is commonly employed to provide mechanical ventilation in the intensive care unit when lung compliance is poor or when airway resistance is irreversibly high. Modification of the inspiratory-expiratory ratio to include inspiratory-expiratory ratio reversal and permissive hypercapnia can also be used when lung disease or injury is severe. Because other donor organs often can be saved for transplantation even when the lungs have been badly damaged, the organ procurement coordinator should adopt pressure-limited ventilation as well as inspiratory-expiratory ratio reversal and permissive hypercapnia as potentially helpful methods while providing mechanical ventilation to selected donors.

The Respiratory System

2019 ◽  
Author(s):  
Zerlina Wong ◽  
Michael Nurok
Keyword(s):  
Carbon Dioxide ◽  
Respiratory System ◽  
Airway Resistance ◽  
Respiratory Mechanics ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Lung Compliance ◽  
The Body ◽  
Elastic Recoil ◽  
Carbon Dioxide Transport ◽  
Pulmonary Vasoconstriction

The pulmonary system is crucial for survival. Managing respiratory mechanics and airway requires a sophisticated understanding of pulmonary physiology. This chapter discusses the ways in which oxygen is brought into the body and carbon dioxide is expelled and reviews the principles of respiratory mechanics, including lung compliance, airway resistance, chemoreceptor and mechanoreceptor control of ventilation, hypoxic pulmonary vasoconstriction, distribution of perfusion, and other properties that affect oxygen and carbon dioxide transport. The respiratory system exists in a state of equilibrium, where the inward elastic recoil of the lungs is balanced with the outward elastic recoil of the chest wall. Airway resistance and compliance are important factors that affect ventilation and air movement. This chapter reviews the role that chemoreceptors and mechanoreceptors have on controlling ventilation, as well as the effects that hypercarbia and hypoxemia have on pulmonary and cerebral circulation, and the Bohr and Haldane effects that elucidate understanding of the hemoglobin dissociation curve. These principles all inform the care of patients who require mechanical ventilation, as we endeavor to support them through their surgery or intensive care stay. This review contains 7 figures and 38 references. Key Words: apneic oxygenation, Bohr effect, chemoreceptors, compliance, Haldane effect, hypoxic pulmonary vasoconstriction, resistance, respiratory mechanics, ventilation-perfusion

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 Robustness of two different methods of monitoring respiratory system compliance during mechanical ventilation

2017 ◽  
Vol 55 (10) ◽  
pp. 1819-1828 ◽  
Author(s):  
Gaetano Perchiazzi ◽  
Christian Rylander ◽  
Mariangela Pellegrini ◽  
Anders Larsson ◽  
Göran Hedenstierna
Keyword(s):  
Mechanical Ventilation ◽  
Respiratory System ◽  
Respiratory System Compliance

scholarly journals COMPARING TWO DIFFERENT MODES OF MECHANICAL VENTILATION BY THE LEAST SQUARE FITTING METHOD: NAVA VERSUS PSV

2015 ◽  
Vol 3 (Suppl 1) ◽  
pp. A319
Author(s):  
S Spadaro ◽  
S Grasso ◽  
V Cricca ◽  
F Dalla Corte ◽  
R Di Mussi ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Least Square ◽  
Least Square Fitting ◽  
Fitting Method ◽  
Least Square Fitting Method

Mucormycosis: A Black Fungus- Post Covid Complications

2021 ◽  
Author(s):  
Prithiv Kumar KR
Keyword(s):  
Mechanical Ventilation ◽  
T Cells ◽  
Intensive Care ◽  
Fungal Infection ◽  
Intensive Care Units ◽  
Respiratory System ◽  
Cd8 T Cells ◽  
Transmitted Disease ◽  
Global Pandemic

Human to human transmitted disease is the game of coronavirus disease (COVID-19) transmission and it had been declared an emergency global pandemic that caused major disastrous in the respiratory system to more than five million people and killing more than half a billion deaths across the globe. Besides lower acute respiratory syndrome, there is damage to the alveolar with severe inflammatory exudation. COVID-19 patients often have lower immunosuppressive CD4+ T and CD8+ T cells and most patients in intensive care units (ICU) need mechanical ventilation, hence longer stay in hospitals. These patients have been discovered to develop fungal co-infections. COVID-19 patients develop what is known as mucormycosis a black fungal infection that is deadly leading to loss of sight and hearing and eventually death. This chapter will focus on mucormycosis, a black fungus caused during post covid complications.

scholarly journals Thoracic sympathetic block reduces respiratory system compliance

2007 ◽  
Vol 125 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Fábio Ely Martins Benseñor ◽  
Joaquim Edson Vieira ◽  
José Otávio Costa Auler Júnior
Keyword(s):  
Chest Wall ◽  
Respiratory System ◽  
Lung Resection ◽  
Lung Compliance ◽  
Airway Hyperreactivity ◽  
Sympathetic Block ◽  
Respiratory System Compliance ◽  
Double Blind ◽  
Thoracic Epidural ◽  
Student’S T

CONTEXT AND OBJECTIVE: Thoracic epidural anesthesia (TEA) following thoracic surgery presents known analgesic and respiratory benefits. However, intraoperative thoracic sympathetic block may trigger airway hyperreactivity. This study weighed up these beneficial and undesirable effects on intraoperative respiratory mechanics. DESIGN AND SETTING: Randomized, double-blind clinical study at a tertiary public hospital. METHODS: Nineteen patients scheduled for partial lung resection were distributed using a random number table into groups receiving active TEA (15 ml 0.5% bupivacaine, n = 9) or placebo (15 ml 0.9% saline, n = 10) solutions that also contained 1:200,000 epinephrine and 2 mg morphine. Under general anesthesia, flows and airway and esophageal pressures were recorded. Pressure-volume curves, lower inflection points (LIP), resistance and compliance at 10 ml/kg tidal volume were established for respiratory system, chest wall and lungs. Student’s t test was performed, including confidence intervals (CI). RESULTS: Bupivacaine rose 5 ± 1 dermatomes upwards and 6 ± 1 downwards. LIP was higher in the bupivacaine group (6.2 ± 2.3 versus 3.6 ± 0.6 cmH2O, p = 0.016, CI = -3.4 to -1.8). Respiratory system and lung compliance were higher in the placebo group (respectively 73.3 ± 10.6 versus 51.9 ± 15.5, p = 0.003, CI = 19.1 to 23.7; 127.2 ± 31.7 versus 70.2 ± 23.1 ml/cmH2O, p < 0.001, CI = 61 to 53). Resistance and chest wall compliance showed no difference. CONCLUSION: TEA decreased respiratory system compliance by reducing its lung component. Resistance was unaffected. Under TEA, positive end-expiratory pressure and recruitment maneuvers are advisable.

Sign in / Sign up

Export Citation Format

Share Document