Pulmonary stretch receptor activity during partial liquid ventilation with different pressure waveforms.

Background: The aim of the present study was to investigate pulmonary stretch receptor activity (PSR) under different peak inspiratory pressures (PIPs) and inspiratory pressure waveforms during partial liquid (PLV) and gas ventilation (GV).
Methods: PSR instantaneous impulse frequency (PSRf _imp ) was recorded from single fibers in the vagal nerve during PLV and GV in young cats. PIPs were set at 1.2/1.8/2.2/2.7 kPa, and square and sinusoidal pressure waveforms were applied.
Results: PSRf _imp at the start of inspiration increased with increasing PIPs, and was steeper and higher with square than with sinusoidal waveforms (p < 0.05). Total number of impulses, peak and mean PSRf _imp were lower during PLV than GV at the lowest and highest PIPs (p < 0.025). Time to peak PSRf _imp was shorter with square than with sinusoidal waveforms at all pressures and ventilations (p < 0.005). Irrespective of waveform, lower PIPs yielded lower ventilation during PLV.
Conclusion: As assessed by PSRf _imp , increased PIPs do not expose the lungs to more stretching during PLV than during GV, with only minor differences between square and sinusoidal waveforms.
Competing Interests: Declaration of Competing Interest The authors declare that they have no competing interests
(Copyright © 2020. Published by Elsevier B.V.)