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Respiratory system
Published in Jagdish M. Gupta, John Beveridge, MCQs in Paediatrics, 2020
Jagdish M. Gupta, John Beveridge
7.6. During an episode of acute bronchiolitislung volume is high.transpulmonary pressure is decreased.alveolar ventilation is initially increased.hypoxia is due to intrapulmonary shunting.gaseous diffusion is the major respiratory physiological disturbance.
Functions of the Respiratory System
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
The lungs lie within the thorax, covered by the visceral pleura and separated from the parietal pleura on the inside of the chest wall by the (potential) intrapleural space. The diaphragm separates the lungs from the abdominal contents. The elastic forces of the lung and the chest wall are in equilibrium; the tendency of the lung is to collapse (contract down), and the tendency of the chest wall is to expand (muscle tone in the diaphragm also contributes to this), resulting in a negative intrapleural pressure (Figure 15.1). Therefore, the transmural pressure gradient that tends to distend the alveolar wall (called the transpulmonary pressure) increases. Transpulmonary pressure is the difference between alveolar and intrapleural pressures. At the end of a normal expiration, the two opposing forces balance and the lung volume is at FRC.
The respiratory system
Published in Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella, Essentials of Human Physiology and Pathophysiology for Pharmacy and Allied Health, 2019
Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella
In between breaths, the transpulmonary pressure is +5 mmHg. The transpulmonary pressure is also referred to as the expanding pressure of the lungs. A force of +5 mmHg expands, or pushes outward on, the lungs so that they fill the thoracic cavity. As might be expected, during inspiration, the transpulmonary pressure increases, causing greater expansion of the lungs:
Lung and diaphragm protective ventilation: a synthesis of recent data
Published in Expert Review of Respiratory Medicine, 2022
Vlasios Karageorgos, Athanasia Proklou, Katerina Vaporidi
The transpulmonary pressures can also be used to evaluate end-expiratory alveolar collapse and end-inspiratory over-distention. Specifically, targeting a low positive end-expiratory transpulmonary pressure for PEEP titration was associated with reduced atelectasis in both experimental and clinical settings [25,26]. A recent reanalysis of a large clinical trial showed that PEEP titrated to end-expiratory transpulmonary pressure closer to 0 cm H2O was associated with greater survival than more positive or negative values [27]. The end-inspiratory transpulmonary pressure can be used as an indicator of over-distention, and should preferably be measured with the elastance-derived method (PL,end-insp = Ppl x EL/ERS) as it has been shown in a study in human cadavers to better represent the true PL at end-inspiration of the nondependent regions [26].
Prognostic value of pulmonary artery pulsatility index in chronic heart failure patients with reduced ejection fraction
Published in Acta Cardiologica, 2022
At the end of expiration following parameters were measured one after the other: pulmonary capillary wedge pressure (PCWP), pulmonary artery systolic and diastolic pressure (PASP and PADP), and RAP. MAP was recorded. By utilising Fick's equation, we calculated cardiac output (CO), then dividing by body surface area, we obtained the cardiac index (CI). The transpulmonary pressure gradient (TPG) was computed as mean PA pressure minus PCWP and reported in mm Hg. Dividing TPG by CO, the pulmonary vascular resistance (PVR) was calculated and represented in units of dynxsec/cm5. PAPG was calculated as PASP minus PADP and reported in mm Hg. The right ventricular function was assessed by calculation of PAPi according to the following formula: PAPi = PAPG/RAP.
Efficacy of transalveolar pressure measurement as a monitoring parameter for lung recruitment in postcardiac surgery hypoxic patients
Published in Egyptian Journal of Anaesthesia, 2021
Ibrahim Mabrouk Ibrahim, Ahmed Yousef, Amal Sabry, Ayman Khalifa
In agreement with the current study in the use of PTA Insp in the detection of the alveolar overdistention, Arnal et al. [11] reported that the transalveolar pressure inspiratory should be kept below 15 cmH2O and the increase above this pressure was considered as an alveolar overdistention. Also authors reported that the transalveolar pressure was more accurate than transpulmonary pressure in evaluation of the alveolar condition during inflation and deflation.