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Volume 3 Supplement 1

ESICM LIVES 2015

Effect of different pressure-targeted modes of ventilation on transpulmonary pressure and inspiratory effort

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Introduction

Spontaneous breathing during mechanical ventilation improves gas exchange and might prevent ventilator-induced diaphragm dysfunction. In pressure-targeted modes, transpulmonary pressure (PL) is the sum of pressure generated by the ventilator and muscular pressure. When inspiratory effort increases, PL and tidal volume (VT) increase, potentially resulting in lung injury. This effect depends on the degree of inspiratory synchronization (i-sync); pressure-targeted modes can be classified into fully, partially, and non i-sync modes. A bench study [1] demonstrated that non-i-sync mode resulted in lower PL and VT than other modes, protecting the lungs from injury. We undertook to assess the effect of varying synchronization during pressure-targeted ventilation in critically ill patients.

Objectives

To compare VT, PL, inspiratory effort (esophageal pressure-time product, PTPeso) and respiratory drive (airway occlusion pressure, P0.1) during three pressure-targeted modes with different degrees of i-sync.

Methods

We conducted a randomized cross-over physiological study in spontaneously breathing ventilated patients. Twelve patients were enrolled (1 subsequently withdrew). Three pressure-targeted modes (Evita XL, Draeger, Germany) including fully (PC-CMV), partially (PC-SIMV), and non i-sync (APRV) modes were sequentially applied for 20 minutes in random order using the same driving pressure, PEEP and inspiratory time. Airway, esophageal, and gastric pressures, P0.1, and flow were recorded along with gas exchange and hemodynamics. PL and PTPeso were calculated.

Results

11/12 patients successfully completed the study. VT was significantly lower during non i-sync mode than fully i-sync mode (Table 1, p = 0.003) and VT variability increased from 13 % to 35 % with decreasing inspiratory synchronization. Maximal PL was significant lower in non-i-sync mode than in partially or fully i-sync modes (p = 0.008). There were no significant differences in gas exchange and hemodynamic parameters between modes. PTPeso was significantly higher with non i-sync modes (Table 1, p = 0.047). This increase in PTPeso was observed in the 6 patients who were not receiving intravenous sedation; no increase was observed in the 5 patients receiving continuous intravenous sedation (Figure 1).

Table 1 Table 1
Figure 1
figure1

Effect of intravenous sedation on PTPeso.

Conclusions

Non synchronized pressure-targeted ventilation lowers VT and PL in comparison to fully and partially synchronized modes in spontaneously breathing ventilated patients, even with the same driving pressure. Appropriate sedation may be important to alleviate increased patient effort during such modes.

Grant Acknowledgment

This study was supported by Dr. Brochard Laboratory Research Funding and by a grant from Siriraj Hospital in Bangkok, Thailand.

References

  1. 1.

    Richard JC, Lyazidi A, Akoumianaki E, Mortaza S, Cordioli RL, Lefebvre JC, et al: Potentially harmful effects of inspiratory synchronization during pressure preset ventilation. Intensive Care Med. 2013, 39 (11): 2003-10. 10.1007/s00134-013-3032-7.

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Author information

Correspondence to N Rittayamai.

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Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0), which permits use, duplication, adaptation, distribution, and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

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Rittayamai, N., Beloncle, F., Waheed, R. et al. Effect of different pressure-targeted modes of ventilation on transpulmonary pressure and inspiratory effort. ICMx 3, A825 (2015) doi:10.1186/2197-425X-3-S1-A825

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Keywords

  • Driving Pressure
  • Inspiratory Effort
  • Transpulmonary Pressure
  • Airway Occlusion
  • Grant Acknowledgment