Effects of end-expiratory lung volume versus PaO2 guided PEEP determination on respiratory mechanics and oxygenation in moderate to severe ARDS

2021 ◽  
pp. 1-11
Author(s):  
Kazim Rollas ◽  
Pervin Hanci ◽  
Arzu Topeli
Keyword(s):  
Lung Volume ◽  
Respiratory Mechanics ◽  
Volume Versus

scholarly journals Effect of Bronchoscopic Lung Volume Reduction in Advanced Emphysema on Energy Balance Regulation

Respiration ◽  
2021 ◽  
pp. 1-8
Author(s):  
Karin Sanders ◽  
Karin Klooster ◽  
Lowie E.G.W. Vanfleteren ◽  
Guy Plasqui ◽  
Anne-Marie Dingemans ◽  
...  
Keyword(s):  
Energy Balance ◽  
Lung Volume ◽  
Respiratory Mechanics ◽  
Volume Reduction ◽  
Fat Free Mass ◽  
Whole Body ◽  
Energy Requirements ◽  
Lung Volume Reduction ◽  
Clinical Trial Registry ◽  
The Impact

<b><i>Background:</i></b> Hypermetabolism and muscle wasting frequently occur in patients with severe emphysema. Improving respiratory mechanics by bronchoscopic lung volume reduction (BLVR) might contribute to muscle maintenance by decreasing energy requirements and alleviating eating-related dyspnoea. <b><i>Objective:</i></b> The goal was to assess the impact of BLVR on energy balance regulation. <b><i>Design:</i></b> Twenty emphysematous subjects participated in a controlled clinical experiment before and 6 months after BLVR. Energy requirements were assessed: basal metabolic rate (BMR) by ventilated hood, total daily energy expenditure (TDEE) by doubly labelled water, whole body fat-free mass (FFM) by deuterium dilution, and physical activity by accelerometry. Oxygen saturation, breathing rate, and heart rate were monitored before, during, and after a standardized meal via pulse oximetry and dyspnoea was rated. <b><i>Results:</i></b> Sixteen patients completed follow-up, and among those, 10 patients exceeded the minimal clinically important difference of residual volume (RV) reduction. RV was reduced with median (range) 1,285 mL (−2,430, −540). Before BLVR, 90% of patients was FFM-depleted despite a normal BMI (24.3 ± 4.3 kg/m<sup>2</sup>). BMR was elevated by 130%. TDEE/BMR was 1.4 ± 0.2 despite a very low median (range) daily step count of 2,188 (739, 7,110). Following BLVR, the components of energy metabolism did not change significantly after intervention compared to before intervention, but BLVR treatment decreased meal-related dyspnoea (4.1 vs. 1.7, <i>p</i> = 0.019). <b><i>Conclusions:</i></b> Impaired respiratory mechanics in hyperinflated emphysematous patients did not explain hypermetabolism. <b><i>Clinical Trial Registry Number:</i></b> NCT02500004 at www.clinicaltrial.gov.

scholarly journals Airway Closure during Surgical Pneumoperitoneum in Obese Patients

2019 ◽  
Vol 131 (1) ◽  
pp. 58-73 ◽  
Author(s):  
Domenico Luca Grieco ◽  
Gian Marco Anzellotti ◽  
Andrea Russo ◽  
Filippo Bongiovanni ◽  
Barbara Costantini ◽  
...  
Keyword(s):  
Lung Volume ◽  
Respiratory Mechanics ◽  
Lung Mechanics ◽  
Control Group ◽  
Obese Patients ◽  
Airway Closure ◽  
Alveolar Pressure ◽  
Opening Pressure ◽  
Airway Opening ◽  
Pressure Controlled

AbstractEditor’s PerspectiveWhat We Already Know about This TopicWhat This Article Tells Us That Is NewBackgroundAirway closure causes lack of communication between proximal airways and alveoli, making tidal inflation start only after a critical airway opening pressure is overcome. The authors conducted a matched cohort study to report the existence of this phenomenon among obese patients undergoing general anesthesia.MethodsWithin the procedures of a clinical trial during gynecological surgery, obese patients underwent respiratory/lung mechanics and lung volume assessment both before and after pneumoperitoneum, in the supine and Trendelenburg positions, respectively. Among patients included in this study, those exhibiting airway closure were compared to a control group of subjects enrolled in the same trial and matched in 1:1 ratio according to body mass index.ResultsEleven of 50 patients (22%) showed airway closure after intubation, with a median (interquartile range) airway opening pressure of 9 cm H2O (6 to 12). With pneumoperitoneum, airway opening pressure increased up to 21 cm H2O (19 to 28) and end-expiratory lung volume remained unchanged (1,294 ml [1,154 to 1,363] vs. 1,160 ml [1,118 to 1,256], P = 0.155), because end-expiratory alveolar pressure increased consistently with airway opening pressure and counterbalanced pneumoperitoneum-induced increases in end-expiratory esophageal pressure (16 cm H2O [15 to 19] vs. 27 cm H2O [23 to 30], P = 0.005). Conversely, matched control subjects experienced a statistically significant greater reduction in end-expiratory lung volume due to pneumoperitoneum (1,113 ml [1,040 to 1,577] vs. 1,000 ml [821 to 1,061], P = 0.006). With airway closure, static/dynamic mechanics failed to measure actual lung/respiratory mechanics. When patients with airway closure underwent pressure-controlled ventilation, no tidal volume was inflated until inspiratory pressure overcame airway opening pressure.ConclusionsIn obese patients, complete airway closure is frequent during anesthesia and is worsened by Trendelenburg pneumoperitoneum, which increases airway opening pressure and alveolar pressure: besides preventing alveolar derecruitment, this yields misinterpretation of respiratory mechanics and generates a pressure threshold to inflate the lung that can reach high values, spreading concerns on the safety of pressure-controlled modes in this setting.

scholarly journals Preemptive Alveolar Recruitment Maneuver Followed by PEEP in Obese Patients Undergoing Laparoscopic Gastric Banding. Does it make a Difference? A Randomized Controlled Clinical Study

2019 ◽  
Vol 13 (1) ◽  
pp. 31-39
Author(s):  
Sherif A. Elokda ◽  
Hanan M. Farag
Keyword(s):  
Gastric Banding ◽  
Lung Volume ◽  
Respiratory Mechanics ◽  
Recruitment Maneuver ◽  
Laparoscopic Gastric Banding ◽  
Alveolar Recruitment ◽  
Controlled Study ◽  
Obese Patients ◽  
Alveolar Recruitment Maneuver ◽  
Standard Ventilation

Background: Impaired respiratory functions during general anesthesia are commonly caused by lung atelectasis more in morbidly obese patients. This occurs more frequently with laparoscopic surgery due to trendelenburg position and pneumoperitoneum. Preemptive recruitment maneuver + PEEP results in the prevention of these changes. Aim: To quantitate the effects of RM and PEEP on intraoperative hypoxemia and respiratory mechanics during laparoscopic gastric banding in obese patients. Study Design: A randomized, double-blinded, controlled study. Method and Materials: Fifty adults ASA I-II, BMI (40-50 kg/m2) for elective laparoscopic gastric banding were randomized into, groups C, and RM, 25 patients each. Group C patients received standard ventilation, VT 6 ml/kg, I: E ratio 1: 2 PEEP 5 cm H2O, and respiratory rate 10-12 breaths/ min. RM patients received standard ventilation with one alveolar recruitment maneuver after mechanical ventilation with PEEP of 15 cm H2O till the end of the surgery. Heart rate, mean blood pressure, respiratory mechanical parameters: peak airway pressure, plateau pressure and end-expiratory lung volume, PaO2, PaO2/FiO2 and (SpO2) were assessed. Results: PaO2 and PaO2/FiO2 ratio increased significantly in the RM group after RM from T2 (before pneumoperitoneum) to T6 (end of surgery) compared with group C (P < 0.001). Peak and plateau airway pressures increased significantly in group C from T2 till T5 (60 min after pneumoperitoneum) compared with the RM group (P < 0.001). End-expiratory lung volume increased significantly in the RM group after RM compared with group C (P<0.001). Conclusion: Preemptive RM with PEEP of 15 cm H2O was effective in preventing pneumoperitoneum-induced intraoperative hypoxemia and respiratory mechanics changes.

Methacholine responsiveness in mice from 2 to 8 wk of age

2007 ◽  
Vol 103 (2) ◽  
pp. 542-546 ◽  
Author(s):  
Elizabeth M. Bozanich ◽  
Tibor Z. Jánosi ◽  
Rachel A. Collins ◽  
Cindy Thamrin ◽  
Debra J. Turner ◽  
...  
Keyword(s):  
Lung Volume ◽  
Respiratory Mechanics ◽  
Age Groups ◽  
Model Fitting ◽  
Residual Volume ◽  
Response Curves ◽  
Asthma Phenotype ◽  
Adult Mice ◽  
Airway Response ◽  
Airway Responses

Many chronic human lung diseases have their origin in early childhood, yet most murine models used to study them utilize adult mice. An important component of the asthma phenotype is exaggerated airway responses, frequently modelled by methacholine (MCh) challenge. The present study was undertaken to characterize MCh responses in mice from 2 to 8 wk of age measuring absolute lung volume and volume-corrected respiratory mechanics as outcome variables. Female BALB/c mice aged 2, 3, 4, 6, and 8 wk were studied during cumulative intravenous MCh challenge. Following each MCh dose, absolute lung volume was measured plethysmographically at functional residual volume and during a slow inflation to 20-hPa transrespiratory pressure. Respiratory system impedance was measured continuously during the inflation maneuver and partitioned into airway and constant-phase parenchymal components by model fitting. Volume-corrected (specific) estimates of respiratory mechanics were calculated. Intravenous MCh challenge induced a predominantly airway response with no evidence of airway closure in any age group. No changes in functional residual volume were seen in mice of any age during the MCh challenge. The specific airway resistance MCh dose response curves did not show significant differences between the age groups. The results from the present study do not show systematic differences in MCh responsiveness in mice from 2 to 8 wk of age.

Decreasing size of cardiogenic oscillations reflects decreasing compliance of the respiratory system during long-term ventilation

2004 ◽  
Vol 96 (3) ◽  
pp. 879-884 ◽  
Author(s):  
Michael Lichtwarck-Aschoff ◽  
Bela Suki ◽  
Anders Hedlund ◽  
Ulf H. Sjöstrand ◽  
Agneta Markström ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Lung Volume ◽  
Respiratory Mechanics ◽  
Mechanical Energy ◽  
Lung Compliance ◽  
Beating Heart ◽  
Cardiogenic Oscillations ◽  
Long Term Ventilation ◽  
Mechanical Disturbances

Part of the energy produced by the heartbeat is transferred to the lung and promotes intrapulmonary gas mixing. It is likely that this transmission in the form of local mechanical disturbances affects and reflects respiratory mechanics. The effects of the cardiogenic oscillations were studied in seven piglets during 7 h of monotonous mechanical ventilation. During the 1st h of ventilation, every heartbeat triggered a noticeable transient increase in lung volume of 14 ml (95% confidence interval = 10-17 ml). After 7 h, the increase in lung volume due to heartbeat significantly decreased to 7 ml (95% confidence interval = 2-9 ml, P < 0.05). During the course of ventilation, overall lung compliance and gas exchange were progressively compromised. We conclude that 1) sufficient mechanical energy is transferred from the beating heart to the lung to increase lung volume, and 2) the ability of the heartbeats to help increase lung volume is reduced during long-term ventilation, which reflects the changes in lung compliance.

scholarly journals Effects of Inhaled Fenoterol and Positive End-Expiratory Pressure on the Respiratory Mechanics of Patients with Chronic Obstructive Pulmonary Disease

2005 ◽  
Vol 12 (6) ◽  
pp. 329-335 ◽  
Author(s):  
Claude Guerin ◽  
Pierre-Guy Durand ◽  
Cécile Pereira ◽  
Jean-Christophe Richard ◽  
Jean-Charles Poupelin ◽  
...  
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Respiratory System ◽  
Lung Volume ◽  
Respiratory Mechanics ◽  
Chronic Obstructive ◽  
Flow Limitation ◽  
Total Resistance ◽  
Positive End Expiratory Pressure ◽  
Expiratory Flow Limitation ◽  
Obstructive Pulmonary Disease

BACKGROUND: During acute ventilatory failure in patients with chronic obstructive pulmonary disease (COPD), applying external positive end-expiratory pressure (PEEPe) will reopen small airways and, thus, may enhance peripheral deposition as well as the physiological effects of inhaled beta-2 agonists.OBJECTIVE: To investigate the efficacy of inhaled fenoterol applied by zero end-expiratory pressure (ZEEPe) or PEEPe.METHODS: Ten patients with COPD who were intubated and mechanically ventilated received fenoterol (10 mg/4 mL) via the ventilator using a jet nebulizer for 30 min on ZEEPe and PEEPe set at 80% of the total PEEP in a random order. The total resistance of the respiratory system (rapid airway occlusion technique), change in end-expiratory lung volume and expiratory flow limitation were assessed before and 5 min, 15 min, 30 min, 60 min and 240 min after fenoterol inhalation.RESULTS: Before inhalation and 60 min after inhalation, the total PEEP, the change in end-expiratory lung volume and the total resistance of the respiratory system were 8±3 cmH2O and 6±3 cmH2O, 0.61±0.34 L and 0.43±0.32 L, and 26±7 cmH2O/L/s and 23±6 cmH2O/L/s, respectively, with ZEEPe, and 9±3 cmH2O and 8±3 cmH2O (P<0.05 versus ZEEPe), 0.62±0.34 L and 0.62±0.37 L (P<0.05 versus ZEEPe), and 26±9 H2O/L/s and 25±9 H2O/L/s, respectively, with PEEPe. Three patients became not flow-limited under the combination of PEEPe and fenoterol.CONCLUSIONS: In patients with COPD, fenoterol combined with PEEPe has opposing effects on respiratory mechanics. First, it does not significantly reduce lung hyperinflation or inspiratory resistances. Second, it allows expiratory flow limitation reversal in some patients. These findings result from the net effect on end-expiratory lung volume of each intervention. This implies that if fenoterol is used in combination with PEEPe, the level of PEEPe should be reassessed during the time course of the drug to prevent any further lung hyperinflation.

scholarly journals High-frequency oscillatory ventilation in neonatal RDS: initial volume optimization and respiratory mechanics

1998 ◽  
Vol 84 (4) ◽  
pp. 1174-1177 ◽  
Author(s):  
Masendu Kalenga ◽  
Oreste Battisti ◽  
Anne François ◽  
Jean-Paul Langhendries ◽  
Dale R. Gerstmann ◽  
...  
Keyword(s):  
Respiratory System ◽  
Lung Volume ◽  
High Frequency ◽  
Distress Syndrome ◽  
Respiratory Mechanics ◽  
High Frequency Oscillatory Ventilation ◽  
Oscillatory Ventilation ◽  
Respiratory System Resistance ◽  
High Frequency Oscillatory ◽  
Good Oxygenation

To determine whether initial lung volume optimization influences respiratory mechanics, which could indicate the achievement of optimal volume, we studied 17 premature infants with respiratory distress syndrome (RDS) assisted by high-frequency oscillatory ventilation. The continuous distending pressure (CDP) was increased stepwise from 6–8 cmH2O up to optimal CDP (OCDP), i.e., that allowing good oxygenation with the lowest inspired O2 fraction. Respiratory system compliance (Crs) and resistance were concomitantly measured. Mean OCDP was 16.5 ± 1.2 cmH2O. Inspired O2 fraction could be reduced from an initial level of 0.73 ± 0.17 to 0.33 ± 0.07. However, Crs (0.45 ± 0.14 ml ⋅ cmH2O−1 ⋅ kg−1at starting CDP point) remained unchanged through lung volume optimization but appeared inversely related to OCDP. Similarly, respiratory system resistance was not affected. We conclude that there is a marked dissociation between oxygenation improvement and Crs profile during the initial phase of lung recruitment by early high-frequency oscillatory ventilation in infants with RDS. Thus optimal lung volume cannot be defined by serial Crs measurement. At the most, low initial Crs suggests that higher CDP will be needed.

Effect of PEEP on respiratory mechanics in anesthetized paralyzed humans

1992 ◽  
Vol 73 (5) ◽  
pp. 1736-1742 ◽  
Author(s):  
E. D′Angelo ◽  
E. Calderini ◽  
M. Tavola ◽  
D. Bono ◽  
J. Milic-Emili
Keyword(s):  
Chest Wall ◽  
Lung Volume ◽  
Respiratory Mechanics ◽  
Viscoelastic Model ◽  
Esophageal Pressure ◽  
Airway Occlusion ◽  
Flow Interruption ◽  
Peep Ventilation ◽  
Overall Resistance ◽  
Viscoelastic Constants

With the use of the technique of rapid airway occlusion during constant flow inflation, respiratory mechanics were studied in eight anesthetized paralyzed supine normal humans during zero (ZEEP) and positive end-expiratory pressure (PEEP) ventilation. PEEP increased the end-expiratory lung volume by 0.49 liter. The changes in transpulmonary and esophageal pressure after flow interruption were analyzed in terms of a seven-parameter “viscoelastic” model. This allowed assessment of static lung and chest wall elastance (Est,L and Est,W), partitioning of overall resistance into airway interrupter (Rint,L) and tissue resistances (delta RL and delta RW), and computation of lung and chest wall “viscoelastic constants.” With increasing flow, Rint,L increased, whereas delta RL and delta RW decreased, as predicted by the model. Est,L, Est,W, and Rint,L decreased significantly with PEEP because of increased lung volume, whereas delta R and viscoelastic constants of lung and chest wall were independent of PEEP. The results indicate that PEEP caused a significant decrease in Rint,L, Est,L, and Est,W, whereas the dynamic tissue behavior, as reflected by delta RL and delta RW, did not change.

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