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Seminars in Respiratory and Critical... Jun 2022Mechanical ventilation is a life-support system used to ensure blood gas exchange and to assist the respiratory muscles in ventilating the lung during the acute phase of...
Mechanical ventilation is a life-support system used to ensure blood gas exchange and to assist the respiratory muscles in ventilating the lung during the acute phase of lung disease or following surgery. Positive-pressure mechanical ventilation differs considerably from normal physiologic breathing. This may lead to several negative physiological consequences, both on the lungs and on peripheral organs. First, hemodynamic changes can affect cardiovascular performance, cerebral perfusion pressure (CPP), and drainage of renal veins. Second, the negative effect of mechanical ventilation (compression stress) on the alveolar-capillary membrane and extracellular matrix may cause local and systemic inflammation, promoting lung and peripheral-organ injury. Third, intra-abdominal hypertension may further impair lung and peripheral-organ function during controlled and assisted ventilation. Mechanical ventilation should be optimized and personalized in each patient according to individual clinical needs. Multiple parameters must be adjusted appropriately to minimize ventilator-induced lung injury (VILI), including: inspiratory stress (the respiratory system inspiratory plateau pressure); dynamic strain (the ratio between tidal volume and the end-expiratory lung volume, or inspiratory capacity); static strain (the end-expiratory lung volume determined by positive end-expiratory pressure [PEEP]); driving pressure (the difference between the respiratory system inspiratory plateau pressure and PEEP); and mechanical power (the amount of mechanical energy imparted as a function of respiratory rate). More recently, patient self-inflicted lung injury (P-SILI) has been proposed as a potential mechanism promoting VILI. In the present chapter, we will discuss the physiological and pathophysiological consequences of mechanical ventilation and how to personalize mechanical ventilation parameters.
Topics: Humans; Lung; Positive-Pressure Respiration; Respiration, Artificial; Tidal Volume; Ventilator-Induced Lung Injury
PubMed: 35439832
DOI: 10.1055/s-0042-1744447 -
The European Respiratory Journal Feb 2011A meta-analysis including 32 randomised controlled trials on the effects of inspiratory muscle training (IMT) in chronic obstructive pulmonary disease (COPD) patients... (Meta-Analysis)
Meta-Analysis Review
A meta-analysis including 32 randomised controlled trials on the effects of inspiratory muscle training (IMT) in chronic obstructive pulmonary disease (COPD) patients was performed. Overall and subgroup analyses with respect to training modality (strength or endurance training, added to general exercise training) and patient characteristics were performed. Significant improvements were found in maximal inspiratory muscle strength (P(I,max); +13 cmH₂O), endurance time (+261 s), 6- or 12-min walking distance (+32 and +85 m respectively) and quality of life (+3.8 units). Dyspnoea was significantly reduced (Borg score -0.9 point; Transitional Dyspnoea Index +2.8 units). Endurance exercise capacity tended to improve, while no effects on maximal exercise capacity were found. Respiratory muscle endurance training revealed no significant effect on P(I,max), functional exercise capacity and dyspnoea. IMT added to a general exercise programme improved P(I,max) significantly, while functional exercise capacity tended to increase in patients with inspiratory muscle weakness (P(I,max) <60 cmH₂O). IMT improves inspiratory muscle strength and endurance, functional exercise capacity, dyspnoea and quality of life. Inspiratory muscle endurance training was shown to be less effective than respiratory muscle strength training. In patients with inspiratory muscle weakness, the addition of IMT to a general exercise training program improved P(I,max) and tended to improve exercise performance.
Topics: Breathing Exercises; Dyspnea; Female; Humans; Inspiratory Capacity; Male; Muscle Weakness; Physical Endurance; Pulmonary Disease, Chronic Obstructive; Quality of Life; Randomized Controlled Trials as Topic; Resistance Training; Treatment Outcome; Walking
PubMed: 21282809
DOI: 10.1183/09031936.00031810 -
International Journal of Chronic... 2018The relationship of functional parameters such as lung mechanics, chest kinematics, metabolism and peripheral and respiratory muscle function with the level of exercise...
RATIONALE
The relationship of functional parameters such as lung mechanics, chest kinematics, metabolism and peripheral and respiratory muscle function with the level of exercise tolerance remains a controversial subject. While it has been previously shown that pulmonary rehabilitation is capable of improving exercise tolerance in patients afflicted by COPD, as expressed by values of 6-minute walking test (6MWT), the degree of contribution to this change by each of the aforementioned parameters remains unclear.
AIMS
To investigate the correlation between changes in exercise capacity and other functional markers following pulmonary rehabilitation in COPD and to determine which parameters are more closely related to improvements of exercise tolerance.
MATERIALS AND METHODS
Three hundred and twenty-seven patients with COPD (with average, 95% CI for forced expiratory volume in the first second [FEV]: 45% [25%-83%] predicted, age: 64 [48-80] years, and BMI: 27 [13.5-40.4] kg/m) participated in this study. Thirty percent of the patients had pulmonary hypertension as comorbidity. Patients underwent a pulmonary rehabilitation program with 20-30 minutes sessions two to three times per day for 4 weeks. The program was composed of chest wall-stretching, controlled breathing exercises, and a personalized training schedule for cycling and treadmill use. Measurements of 6MWT, lung function, chest wall expansion, grip strength, maximal inspiratory pressure, and breath holding time were taken. The Body mass index, airflow Obstruction, Dyspnea and Exercise capacity (BODE-index), body mass index [BMI], FEV, 6MWT, modified Medical Research Dyspnea Scale score, and an alternative scale score (for BMI, FEV, 6MWT, and COPD Assessment Test) were calculated.
RESULTS
Rehabilitation resulted in a generalized improvement in 6MWT among patients (average: 360 [95% CI: 178-543 m] vs average: 420 [95% CI: 238-601 m], <0.05). Improvements in exercise tolerance were found to be most closely associated with changes in composite BODE-index (=-0.6), Alternative Scale (=-0.56), dyspnea score (modified Medical Research Dyspnea Scale =-0.54), and health status (COPD Assessment Test =-0.4, <0.05). In addition, improvements in exercise tolerance were found to moderately correlate with improvements in inspiratory vital capacity (IVC, =0.34, <0.05). Post-rehabilitation changes in IVC displayed a connection with grip strength (=0.6) and chest expansion (=0.48).
CONCLUSION
Enhancements in exercise tolerance had correlation with changes in IVC, BODE-index, and the new Alternative Scale. However, comprehensive assessment needs to include considerations of chest kinematics and peripheral and respiratory muscle function as well.
Topics: Aged; Aged, 80 and over; Bicycling; Biomechanical Phenomena; Breathing Exercises; Exercise Therapy; Exercise Tolerance; Female; Forced Expiratory Volume; Health Status; Humans; Inspiratory Capacity; Lung; Male; Middle Aged; Muscle Stretching Exercises; Pulmonary Disease, Chronic Obstructive; Recovery of Function; Time Factors; Treatment Outcome; Vital Capacity; Walk Test; Walking
PubMed: 29535512
DOI: 10.2147/COPD.S153525 -
Respiratory Care Oct 2009Maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) are simple, convenient, and noninvasive indices of respiratory muscle strength at the mouth, but... (Review)
Review
Maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) are simple, convenient, and noninvasive indices of respiratory muscle strength at the mouth, but standards are not clearly established. We review recent literature, update the 2002 American Thoracic Society/European Respiratory Society statement, and propose as the best choice using a flanged mouthpiece for reference values and lower limit of normal (LLN) values as a function of age for adults age up to about 70 years. Because male pressures are higher than female and MEP exceeds MIP, we present 4 linear regression reference equations as a function of age for adults age up to approximately 70 years: Male MIP=120-(0.41xage), and male MIP LLN=62-(0.15xage). Male MEP=174-(0.83xage), and male MEP LLN=117-(0.83xage). Female MIP=108-(0.61xage), and female MIP LLN=62-(0.50xage). Female MEP=131-(0.86xage), and female MEP LLN=95-(0.57xage). (Pressure in cm H2O and age in years.) We discuss normal values in older subjects, estimation of LLN values, and the relationship between vital capacity and respiratory muscle strength, and offer a guide to interpretation of maximal pressure measurements. The approach should allow direct implementation of MIP and MEP in a pulmonary function laboratory.
Topics: Age Factors; Aged; Aged, 80 and over; Exhalation; Female; Humans; Inspiratory Capacity; Male; Middle Aged; Muscle Weakness; Reference Values; Respiratory Function Tests; Sex Factors
PubMed: 19796415
DOI: No ID Found -
Journal of Physiotherapy Oct 2015In people with chronic obstructive pulmonary disease, does the Manual Diaphragm Release Technique improve diaphragmatic mobility after a single treatment, or... (Randomized Controlled Trial)
Randomized Controlled Trial
The Manual Diaphragm Release Technique improves diaphragmatic mobility, inspiratory capacity and exercise capacity in people with chronic obstructive pulmonary disease: a randomised trial.
QUESTIONS
In people with chronic obstructive pulmonary disease, does the Manual Diaphragm Release Technique improve diaphragmatic mobility after a single treatment, or cumulatively? Does the technique also improve exercise capacity, maximal respiratory pressures, and kinematics of the chest wall and abdomen?
DESIGN
Randomised, controlled trial with concealed allocation, intention-to-treat analysis, and blinding of participants and assessors.
PARTICIPANTS
Twenty adults aged over 60 years with clinically stable chronic obstructive pulmonary disease.
INTERVENTION
The experimental group received six treatments with the Manual Diaphragm Release Technique on non-consecutive days within a 2-week period. The control group received sham treatments following the same regimen.
OUTCOME MEASURES
The primary outcome was diaphragmatic mobility, which was analysed using ultrasonography. The secondary outcomes were: the 6-minute walk test; maximal respiratory pressures; and abdominal and chest wall kinematics measured by optoelectronic plethysmography. Outcomes were measured before and after the first and sixth treatments.
RESULTS
The Manual Diaphragm Release Technique significantly improved diaphragmatic mobility over the course of treatments, with a between-group difference in cumulative improvement of 18mm (95% CI 8 to 28). The technique also significantly improved the 6-minute walk distance over the treatment course, with a between-group difference in improvement of 22 m (95% CI 11 to 32). Maximal expiratory pressure and sniff nasal inspiratory pressure both showed significant acute benefits from the technique during the first and sixth treatments, but no cumulative benefit. Inspiratory capacity estimated by optoelectronic plethysmography showed significant cumulative benefit of 330ml (95% CI 100 to 560). The effects on other outcomes were non-significant or small.
CONCLUSION
The Manual Diaphragm Release Technique improves diaphragmatic mobility, exercise capacity and inspiratory capacity in people with chronic obstructive pulmonary disease. This technique could be considered in the management of people with chronic obstructive pulmonary disease.
TRIAL REGISTRATION
NCT02212184.
Topics: Aged; Breathing Exercises; Diaphragm; Double-Blind Method; Exercise; Exercise Tolerance; Female; Humans; Inhalation; Inspiratory Capacity; Male; Middle Aged; Pulmonary Disease, Chronic Obstructive; Treatment Outcome
PubMed: 26386894
DOI: 10.1016/j.jphys.2015.08.009 -
The European Respiratory Journal Jan 2018The benefit of inspiratory muscle training (IMT) combined with a pulmonary rehabilitation programme (PRP) is uncertain. We aimed to demonstrate that, in severe and very... (Randomized Controlled Trial)
Randomized Controlled Trial
The benefit of inspiratory muscle training (IMT) combined with a pulmonary rehabilitation programme (PRP) is uncertain. We aimed to demonstrate that, in severe and very severe chronic obstructive pulmonary disease (COPD) patients, IMT performed during a PRP is associated with an improvement of dyspnoea.In a single-blind randomised controlled trial, 150 severe or very severe COPD patients were allocated to follow PRP+IMT PRP alone. The evaluations were performed at inclusion and after 4 weeks. The primary outcome was the change in dyspnoea using the Multidimensional Dyspnoea Profile questionnaire at the end of a 6-min walk test (6MWT) at 4 weeks. Secondary outcomes were changes in dyspnoea using the Borg (end of the 6MWT) and modified Medical Research Council scales and in functional parameters (maximal inspiratory pressure (), inspiratory capacity, 6MWT and quality of life). All analyses were performed on an intention-to-treat basis.Dyspnoea decreased significantly in both groups; however, the improvement of dyspnoea was not statistically different between the two groups. We only found a statistically significant greater increase of after IMT+PRP than after PRP alone.In this trial including severe or very severe COPD patients, we did not find a significant benefit of IMT during PRP+IMT as compared to PRP alone on dyspnoea, despite a significantly higher improvement of in the IMT group.
Topics: Aged; Breathing Exercises; Dyspnea; Exercise Therapy; Female; France; Humans; Inspiratory Capacity; Male; Middle Aged; Pulmonary Disease, Chronic Obstructive; Quality of Life; Respiratory Muscles; Single-Blind Method; Treatment Outcome; Walk Test
PubMed: 29371379
DOI: 10.1183/13993003.01107-2017 -
Intensive Care Medicine Nov 2022
Topics: Humans; Positive-Pressure Respiration; Tidal Volume; Respiration, Artificial
PubMed: 35939095
DOI: 10.1007/s00134-022-06820-z -
Critical Care (London, England) Dec 2017The acute respiratory distress (ARDS) lung is usually characterized by a high degree of inhomogeneity. Indeed, the same lung may show a wide spectrum of aeration... (Review)
Review
The acute respiratory distress (ARDS) lung is usually characterized by a high degree of inhomogeneity. Indeed, the same lung may show a wide spectrum of aeration alterations, ranging from completely gasless regions, up to hyperinflated areas. This inhomogeneity is normally caused by the presence of lung edema and/or anatomical variations, and is deeply influenced by the gravitational forces.For any given airway pressure generated by the ventilator, the pressure acting directly on the lung (i.e., the transpulmonary pressure or lung stress) is determined by two main factors: 1) the ratio between lung elastance and the total elastance of the respiratory system (which has been shown to vary widely in ARDS patients, between 0.2 and 0.8); and 2) the lung size. In severe ARDS, the ventilatable parenchyma is strongly reduced in size ('baby lung'); its resting volume could be as low as 300 mL, and the total inspiratory capacity could be reached with a tidal volume of 750-900 mL, thus generating lethal stress and strain in the lung. Although this is possible in theory, it does not explain the occurrence of ventilator-induced lung injury (VILI) in lungs ventilated with much lower tidal volumes. In fact, the ARDS lung contains areas acting as local stress multipliers and they could multiply the stress by a factor ~ 2, meaning that in those regions the transpulmonary pressure could be double that present in other parts of the same lung. These 'stress raisers' widely correspond to the inhomogenous areas of the ARDS lung and can be present in up to 40% of the lung.Although most of the literature on VILI concentrates on the possible dangers of tidal volume, mechanical ventilation in fact delivers mechanical power (i.e., energy per unit of time) to the lung parenchyma, which reacts to it according to its anatomical structure and pathophysiological status. The determinants of mechanical power are not only the tidal volume, but also respiratory rate, inspiratory flow, and positive end-expiratory pressure (PEEP). In the end, decreasing mechanical power, increasing lung homogeneity, and avoiding reaching the anatomical limits of the 'baby lung' should be the goals for safe ventilation in ARDS.
Topics: Humans; Lung; Pressure; Respiration, Artificial; Respiratory Distress Syndrome; Respiratory Mechanics; Tidal Volume; Ventilators, Mechanical
PubMed: 29297365
DOI: 10.1186/s13054-017-1905-9 -
Respiratory Care Feb 2019Measurements of inspiratory capacity (IC) and vital capacity (VC) are used to recognize dynamic hyperinflation, but appropriate reference values are required to achieve...
BACKGROUND
Measurements of inspiratory capacity (IC) and vital capacity (VC) are used to recognize dynamic hyperinflation, but appropriate reference values are required to achieve accurate clinical interpretations. Altitude above sea level is a potential determining factor for lung volumes, including IC and VC.
OBJECTIVE
To describe IC and VC for healthy people who live in Mexico City at an altitude of 2,240 m above sea level.
METHODS
Healthy subjects ages 9-81 y completed slow spirometry by following 2005 American Thoracic Society/European Respiratory Society standards. Once associations were explored, linear regression models were constructed and values were compared with those from previously published equations.
RESULTS
A total of 441 healthy subjects (55.1% women) participated. The mean age was 32 y (minimum age, 9 y; maximum age, 81 y). IC and VC measurements were associated with sex, age, height, and weight. An accelerated increase in IC and VC was evident from 9 to 20 y of age, followed by a gradual decrease in both sexes. In general, IC was higher in our population than predicted by previously published reference equations.
CONCLUSIONS
IC in healthy people at 2,240 m above sea level was higher than that of previous reports about European and Latin-American subjects of the same height, sex, and age who were at sea level. The present study provided robust reference values for persons who lived at a moderate altitude.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Altitude; Body Height; Body Weight; Child; Female; Healthy Volunteers; Humans; Inspiratory Capacity; Linear Models; Male; Mexico; Middle Aged; Reference Values; Spirometry; Vital Capacity; Young Adult
PubMed: 30647102
DOI: 10.4187/respcare.06284 -
Anesthesiology Apr 2021
Review
Topics: Humans; Inspiratory Capacity; Interactive Ventilatory Support; Respiratory Mechanics; Ventilators, Mechanical
PubMed: 33592102
DOI: 10.1097/ALN.0000000000003704