Pleural pressure

Diaphragm Large abdominal muscle that varies pleural pressure resulting... 

Murphy, D.J., Renninger, J.P, and Gossett, K.A., A novel method for chronic measurement of pleural pressure in conscious rats, /. Pharmacol. Toxicol. Meth., 39, 137-141,1998. 

Fig. 2. Tracings of lung airflow, transpulmonary pressure, and lung volume changes during spontaneous breathing in a rat. Airflow was measured directly using a head-out plethysmograph chamber, while pleural pressure was measured using a pressure sensitive catheter placed into the esophagus within the thoracic cavity. The functional endpoints can be automatically calculated for each breath using a data acquisition and analysis software system.

To provide a direct measure of ventilatory parameters, a head-out plethysmograph chamber is used, while measurement of pleural pressure is used to provide a direct measure of airway resistance and compliance. 

Pleural pressure is measured chronically in conscious rats by surgically implanting a fluid-filled polyurethane catheter (length = 10 cm O.D. = 0.7 mm) attached to a pressure-sensitive radiotelemetry transmitter (Model TA11PA-C40, Data Sciences International, St. Paul, MN) beneath the serosal layer of the esophagus and within the thoracic cavity (see Figure 3). 

Fig. 3. Drawing of a rat showing placement of the pressure sensitive subpleural catheter and radiotelemetry transmitter for chronic measurement of pleural pressure in conscious animals. The enlargement is a cross-section through the esophagus showing the position of the catheter between the serosal and muscularis layers.

To measure compliance, the subject is intubated with an esophageal balloon and then told to breathe in or out of a spirometer in 500-ml increments. During breath holding, with the epiglottis open, the alveolar pressure is the same as the pressure at the mouth. Values of volume change and pleural pressure changes measured simultaneously produce a pressure-volume curve similar to that shown in Fig. 13. 

Figure 2.19 An experimental preparation with left anterior descending coronary pneumatic occluder, subendocardial piezoelectric dimensional sensors in ischemic and non-ischemic zones and left ventricular and pleural pressure sensors. (From D D Glower, J A Spratt, J S Kabas, J W Davis and J S Rankin Quantification of regional myocardial dysfunction after acute ischemic injury, 1988 Am. J. Physiol. 255 Heart Circ. Physiol. 24) H85-H93 1988.)... 

Factors that change with growth. Pp pleural pressure P m transmural pressure (intra-airway pressure-pleural pressure) Pjilyialveolar pressure P Intra-airway pressure. Modified from Wohl (4)... 

Murphy DJ, Renninger JP, Gossett KA (1998) A novel method for chronic measurement of pleural pressure in conscious rats. J Pharmacol Toxicol Methods 39(3) 137-141 Murphy DJ, Renninger JP, Coatney RW (2001) A novel method for chronic measurement of respiratory function in the conscious monkey. J Pharmacol Toxicol Methods 46(l) 13-20 Murphy DJ (2002) Assessment of respiratory function in safety pharmacology. Fundam Clin Pharmacol 16(3) 183-196... 

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