scholarly journals Heart-Protective Mechanical Ventilation in Postoperative Cardiosurgical Patients

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Vadim Mazurok ◽  
Igor Kasherininov ◽  
Andrey Bautin ◽  
Olga Kulemina ◽  
Ryta Rzheutskaya
Keyword(s):  
Mechanical Ventilation ◽  
Tidal Volume ◽  
Airway Pressure ◽  
Artery Bypass ◽  
Intervention Group ◽  
High Peep ◽  
Mean Airway Pressure ◽  
Negative Effects ◽  
Hemodynamic Profile ◽  
Peep Ventilation

Background. This study compared the hemodynamic effects and gas exchange under several different ventilator settings—with regard to tidal volume, respiratory rate, and end-expiratory pressure—in patients after coronary artery bypass grafting (CABG). Methods. Prospective interventional cohort study with a controlled group in a single cardiosurgical ICU involving 119 patients following on-pump CABG surgery. During the 1st postoperative hour, the intervention group patients were ventilated with Vt 10 ml × kg−1, RR 14/min, PEEP 5 cmH2O (“conventional ventilation”). During the 2nd hour, RR was reduced to 8/min (“reduced RR ventilation”). At 3 hrs, Vt was decreased to 6 ml × kg−1, RR returned to 14/min, and PEEP increased to 10 cmH2O (“low Vt-high PEEP ventilation”). Results. Patients in the “low Vt-high PEEP” ventilation period showed significantly lower alveolar ventilation and thoraco-pulmonary compliance than during “reduced RR” ventilation. Mean airway pressure and Vds/Vt peaked during low Vt-high PEEP ventilation; however, driving pressure was lower. Vt decrease and PEEP increase did not lead to oxygenation improvement and worsened CO2 elimination. Hemodynamically, the study revealed significant cardiac output decrease during low Vt-high PEEP ventilation. In 23.2% of patients, catecholamine therapy was initiated. Conclusions. In postoperative cardiosurgical patients, MV with Vt 6 ml × kg−1 and PEEP 10 cm H2O is characterized by worsened oxygenation and elimination of CO2 and a less favorable hemodynamic profile than ventilation with Vt 10 ml × kg−1 and PEEP 5 cmH2O. New and Noteworthy. (i) Patients after CABG may be especially sensitive to low tidal volume and increased PEEP as it negatively affects hemodynamic profile by means of the right heart preload decrease and afterload increase. (ii) Mechanical ventilation settings aiming to minimize mean airway pressure reduce the negative effects of positive inspiratory pressure and are favorable for hemodynamics.

Mechanical Ventilation: Basic Modes

2019 ◽  
pp. 10-16
Author(s):  
Amelia A. Lowell
Keyword(s):  
Mechanical Ventilation ◽  
Tidal Volume ◽  
Respiratory Rate ◽  
Airway Pressure ◽  
Minute Ventilation ◽  
Respiratory Muscles ◽  
Supplemental Oxygen ◽  
Alveolar Ventilation ◽  
Arterial Oxygenation ◽  
Mean Airway Pressure

The main goal of mechanical ventilation is to unload the respiratory muscles to facilitate oxygenation and ventilation. This is accomplished by providing a minute ventilation (VE) (respiratory rate × tidal volume [VT]) that will result in adequate alveolar ventilation coupled with supplemental oxygen and a mean airway pressure that will result in adequate arterial oxygenation.

Estimation of Mortality Risk in Chronically Ventilated Infants With Bronchopulmonary Dysplasia

PEDIATRICS ◽  
1991 ◽  
Vol 88 (6) ◽  
pp. 1153-1160 ◽  
Author(s):  
Debora W. Overstreet ◽  
J. Craig Jackson ◽  
Gerald van Belle ◽  
William E. Truog
Keyword(s):  
Mechanical Ventilation ◽  
Bronchopulmonary Dysplasia ◽  
Airway Pressure ◽  
Life Support ◽  
Water Pressure ◽  
Accurate Estimation ◽  
Regression Equations ◽  
Bacterial Sepsis ◽  
Mean Airway Pressure ◽  
Predictors Of Mortality

Bronchopulmonary dysplasia is a chronic, sometimes fatal lung disease, which primarily affects premature infants and often leads to a dependence on mechanical ventilation lasting many months. To identify prognostic factors of mortality at 1 and 2 months of age, the authors reviewed the medical records of the 144 neonates admitted to two neonatal intensive care units in Seattle from January 1, 1986, through December 31, 1988, who required mechanical ventilation throughout the first month of life. Likely predictors of mortality were tested by logistic regression analysis. The calculated mean airway pressure at 30 days of age (MAP30) and the diagnosis of bacterial sepsis at any time during the first month of life (Bact0-30) were statistically significant predictors of mortality (P < .001 and P = .018, respectively) and had the lowest deviance in the regression model. The probability of mortality was estimated by 1/(1 + e-x, where x = -6.510 + 0.4588 (MAP30) + 1.475 (Bact0-30), and where MAP30 is expressed as centimeters of water pressure (1 cm H2O = 0.0978 kPa) and the presence or absence of bacteremia is 1 and 0, respectively. The records of the 57 infants who still required mechanical ventilation at 60 days of age were reanalyzed with clinical data available during the first 2 months of life. Mean airway pressure (MAP60) and the fraction of inspired oxygen (F60) at 60 days of age combined to form the best predictors of mortality, where x = -7.668 + 0.2940 (MAP60) + 5.935 (F60). The occurrence of bacterial sepsis during the first 2 months of life, the degree of hypochloremia, and the duration of chronic sedative use were also significant predictors of survival, even controlling of MAP60 and F60. These regression equations allow more accurate estimation of the likelihood of survival for chronically ventilated infants and may facilitate decisions regarding withdrawal or continuation of life support.

scholarly journals Can you calculate the total respiratory, lung, and chest wall respiratory mechanics?

2020 ◽  
Vol 1 (1) ◽  
pp. 24-26
Author(s):  
Mia Shokry ◽  
Kimiyo Yamasaki ◽  
Ehab Daoud
Keyword(s):  
Mechanical Ventilation ◽  
Tidal Volume ◽  
Chest Wall ◽  
Airway Pressure ◽  
Respiratory Mechanics ◽  
Peak Inspiratory Pressure ◽  
Esophageal Pressure ◽  
Horizontal Line ◽  
Pulmonary Pressure ◽  
Volume Controlled

Figure: Waveforms for a patient undergoing mechanical ventilation with volume controlled mode. Tidal Volume of 500 ml, PEEP 15, Constant inspiratory flow of 45 l/min A: Airway pressure in cmH2O, B: Esophageal pressure in cmH2O, C: Trans-pulmonary pressure in cmH2O, D: Flow in l/min, E: Tidal volume in ml Red dashed horizontal line: values at end of expiratory occlusion maneuver, White solid horizontal line: values at end of inspiratory occlusion maneuver, Green dashed horizontal line: values during peak inspiratory pressure.

scholarly journals Moderately high frequency ventilation with a conventional ventilator allows reduction of tidal volume without increasing mean airway pressure

2014 ◽  
Vol 2 (1) ◽  
Author(s):  
Ricardo Luiz Cordioli ◽  
Marcelo Park ◽  
Eduardo Leite Vieira Costa ◽  
Susimeire Gomes ◽  
Laurent Brochard ◽  
...  
Keyword(s):  
Tidal Volume ◽  
High Frequency ◽  
Airway Pressure ◽  
High Frequency Ventilation ◽  
Mean Airway Pressure ◽  
Frequency Ventilation

Effects of mean airway pressure and tidal volume on lung and chest wall mechanics in the dog

1993 ◽  
Vol 74 (5) ◽  
pp. 2286-2293 ◽  
Author(s):  
G. M. Barnas ◽  
J. Sprung
Keyword(s):  
Mechanical Properties ◽  
Tidal Volume ◽  
Chest Wall ◽  
Respiratory System ◽  
Lung Volume ◽  
Airway Pressure ◽  
Dynamic Mechanical Properties ◽  
Mean Airway Pressure ◽  
Residual Capacity ◽  
Normal Mean

Dependencies of the dynamic mechanical properties of the respiratory system on mean airway pressure (Paw) and the effects of tidal volume (VT) are not completely clear. We measured resistance and dynamic elastance of the total respiratory system (Rrs and Ers), lungs (RL and EL), and chest wall (Rcw and Ecw) in six healthy anesthetized paralyzed dogs during sinusoidal volume oscillations at the trachea (50–300 ml; 0.4 Hz) delivered at mean Paw from -9 to +23 cmH2O. Changes in end-expiratory lung volume, estimated with inductance plethysmographic belts, showed a typical sigmoidal relationship to mean Paw. Each dog showed the same dependencies of mechanical properties on mean Paw and VT. All elastances and resistances were minimal between 5 and 10 cmH2O mean Paw. All elastances, Rrs, and RL increased greatly with decreasing Paw below 5 cmH2O. Ers and EL increased above 10 cmH2O. Ecw, Ers, Rcw, and Rrs decreased slightly with increasing VT, but RL and EL were independent of VT. We conclude that 1) respiratory system impedance is minimal at the normal mean lung volume of supine anesthetized paralyzed dogs; 2) the dependency of RL on lung volume above functional residual capacity is dependent on VT and respiratory frequency; and 3) chest wall, but not lung, mechanical behavior is nonlinear (i.e., VT dependent) at any given lung volume.

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