Factors affecting the accuracy of esophageal balloon measurement of pleural pressure in dogs

Abstract

Simultaneous measurement of esophageal and tracheal pressures during an occluded inspiratory effort was used to assess the accuracy of the esophageal balloon for measuring pleural pressure in dogs. Esophageal balloons were inserted in five mongrel dogs, and an occlusion test was performed with the balloon tip 5, 10, 15, 20, and 25 cm above the esophageal sphincter; at lung volumes of functional residual capacity (FRC) and FRC + 600 ml; and in supine and right- and left-side lying postures. The protocol was repeated in paralyzed animals. This time the occlusion test was performed by injecting air into a plethysmograph to change the body surface pressure, simulating pressure changes produced by respiratory efforts in spontaneously breathing animals. In 47% of the tests in spontaneously breathing dogs, the slope of esophageal vs. tracheal pressure varied greater than 10% from unity. After paralysis the slope did not vary greater than 5% from unity under any circumstance. These data indicate that the poorer performance of the occlusion test in nonparalyzed dogs is due to active tension in the walls of the esophagus and stress induced in the intrathoracic soft tissues by the descent of the diaphragm during a breathing effort.

Effect of a Nasogastric Tube on Esophageal Pressure Measurement in Normal Adults

“…In most conditions, the majority of points centered along the line of identity, with correlation coefficients between 0.75 and 0.98 (Tables 1 and 2). 12 Despite these apparent problems, a combined esophageal balloon / nasogastric tube catheter appears to yield APes estimates similar to those obtained using a standard esophageal balloon of much smaller diameter.10·11 The graph for positive pressure ventilation shows generally positive values for APes, indicating that most subjects were not breathing passively, thereby introducing an unintended element of variability related to effort.…”

Effect of passive pneumoperitoneum on oesophageal pressure, cardiovascular parameters and blood gas analysis in horses

“…Therefore, it is important to ensure that the location of the balloon is standardised. The balloon was positioned in the caudal third of the oesophagus where pressure values have been shown to be most reliable and repeatable (Dechman et al . 1992).…”

Liquid- and Air-Filled Catheters without Balloon as an Alternative to the Air-Filled Balloon Catheter for Measurement of Esophageal Pressure

“…Noteworthily, other studies reported that an offset exists between absolute values of P pl and P es , and that the agreement between the changes in those two pressures is reduced in mechanically ventilated subjects, supine position, and injured (i.e. more heterogeneous) lungs [10]–[14].…”