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Neural versus pneumatic control of pressure support in patients with chronic obstructive pulmonary diseases at different levels of positive end expiratory pressure: a physiological study.

Liu L, Xia F, Yang Y, Longhini F, Navalesi P, Beck J, Sinderby C, Qiu H - Crit Care (2015)

Bottom Line: Application of extrinsic PEEP (PEEPe) reduces trigger delays and mechanical inspiratory efforts.During PSP, the NeuroSync index was 29 % at zero PEEPe and improved to 21 % at optimal PEEPe (P < 0.05).Both pre-trigger (P < 0.05) and total inspiratory mechanical efforts (P < 0.05) were consistently higher during PSP compared to PSN at same PEEPe.

View Article: PubMed Central - PubMed

Affiliation: Department of Critical Care Medicine, Nanjing Zhongda Hospital, Southeast University, School of Medicine, 87 Dingjiaqiao Street, Nanjing, 210009, China. liulingdoctor@126.com.

ABSTRACT

Introduction: Intrinsic positive end-expiratory pressure (PEEPi) is a "threshold" load that must be overcome to trigger conventional pneumatically-controlled pressure support (PSP) in chronic obstructive pulmonary disease (COPD). Application of extrinsic PEEP (PEEPe) reduces trigger delays and mechanical inspiratory efforts. Using the diaphragm electrical activity (EAdi), neurally controlled pressure support (PSN) could hypothetically eliminate asynchrony and reduce mechanical inspiratory effort, hence substituting the need for PEEPe. The primary objective of this study was to show that PSN can reduce the need for PEEPe to improve patient-ventilator interaction and to reduce both the "pre-trigger" and "total inspiratory" neural and mechanical efforts in COPD patients with PEEPi. A secondary objective was to evaluate the impact of applying PSN on breathing pattern.

Methods: Twelve intubated and mechanically ventilated COPD patients with PEEPi ≥ 5 cm H2O underwent comparisons of PSP and PSN at different levels of PEEPe (at 0 %, 40 %, 80 %, and 120 % of static PEEPi, for 12 minutes at each level on average), at matching peak airway pressure. We measured flow, airway pressure, esophageal pressure, and EAdi, and analyzed neural and mechanical efforts for triggering and total inspiration. Patient-ventilator interaction was analyzed with the NeuroSync index.

Results: Mean airway pressure and PEEPe were comparable for PSP and PSN at same target levels. During PSP, the NeuroSync index was 29 % at zero PEEPe and improved to 21 % at optimal PEEPe (P < 0.05). During PSN, the NeuroSync index was lower (<7 %, P < 0.05) regardless of PEEPe. Both pre-trigger (P < 0.05) and total inspiratory mechanical efforts (P < 0.05) were consistently higher during PSP compared to PSN at same PEEPe. The change in total mechanical efforts between PSP at PEEPe0% and PSN at PEEPe0% was not different from the change between PSP at PEEPe0% and PSP at PEEPe80%.

Conclusion: PSN abolishes the need for PEEPe in COPD patients, improves patient-ventilator interaction, and reduces the inspiratory mechanical effort to breathe.

Trial registration: Clinicaltrials.gov NCT02114567 . Registered 04 November 2013.

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Related in: MedlinePlus

Patient-ventilator interaction for all patients represented topographically. Topographic distribution of triggering error (y-axis) and cycling-off error (x-axis). The red area indicates 80 % of the most frequent patient-ventilator interactions for all breaths in all subjects during neurally triggered and cycled-off pressure support (PSN) (left panels) and pneumatically triggered and cycled-off pressure support (PSP) (right panels) during extrinsic positive end-expiratory pressure (PEEPe)0%, PEEPe40%, PEEPe80%, and PEEPe120%, (top to bottom). See text for details
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Fig2: Patient-ventilator interaction for all patients represented topographically. Topographic distribution of triggering error (y-axis) and cycling-off error (x-axis). The red area indicates 80 % of the most frequent patient-ventilator interactions for all breaths in all subjects during neurally triggered and cycled-off pressure support (PSN) (left panels) and pneumatically triggered and cycled-off pressure support (PSP) (right panels) during extrinsic positive end-expiratory pressure (PEEPe)0%, PEEPe40%, PEEPe80%, and PEEPe120%, (top to bottom). See text for details

Mentions: Figure 2 shows the topographic distribution of timing errors for triggering (y-axis) and cycling-off (x-axis), respectively, for all patients. The red area indicates 80 % of the most frequent patient-ventilator interactions for all breaths in all subjects during PSN (left panels) and PSP (right panels) during PEEPe0%, PEEPe40%, PEEPe80%, and PEEPe120%, (top to bottom). During PSN at PEEPe0% triggering was concentrated within an area ranging from minus 5 % to 25 % for triggering error (Y-axis) and minus 5 % to 5 % error during cycling-off (x-axis) regardless of PEEPe (indicated by box).Fig. 2


Neural versus pneumatic control of pressure support in patients with chronic obstructive pulmonary diseases at different levels of positive end expiratory pressure: a physiological study.

Liu L, Xia F, Yang Y, Longhini F, Navalesi P, Beck J, Sinderby C, Qiu H - Crit Care (2015)

Patient-ventilator interaction for all patients represented topographically. Topographic distribution of triggering error (y-axis) and cycling-off error (x-axis). The red area indicates 80 % of the most frequent patient-ventilator interactions for all breaths in all subjects during neurally triggered and cycled-off pressure support (PSN) (left panels) and pneumatically triggered and cycled-off pressure support (PSP) (right panels) during extrinsic positive end-expiratory pressure (PEEPe)0%, PEEPe40%, PEEPe80%, and PEEPe120%, (top to bottom). See text for details
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4487968&req=5

Fig2: Patient-ventilator interaction for all patients represented topographically. Topographic distribution of triggering error (y-axis) and cycling-off error (x-axis). The red area indicates 80 % of the most frequent patient-ventilator interactions for all breaths in all subjects during neurally triggered and cycled-off pressure support (PSN) (left panels) and pneumatically triggered and cycled-off pressure support (PSP) (right panels) during extrinsic positive end-expiratory pressure (PEEPe)0%, PEEPe40%, PEEPe80%, and PEEPe120%, (top to bottom). See text for details
Mentions: Figure 2 shows the topographic distribution of timing errors for triggering (y-axis) and cycling-off (x-axis), respectively, for all patients. The red area indicates 80 % of the most frequent patient-ventilator interactions for all breaths in all subjects during PSN (left panels) and PSP (right panels) during PEEPe0%, PEEPe40%, PEEPe80%, and PEEPe120%, (top to bottom). During PSN at PEEPe0% triggering was concentrated within an area ranging from minus 5 % to 25 % for triggering error (Y-axis) and minus 5 % to 5 % error during cycling-off (x-axis) regardless of PEEPe (indicated by box).Fig. 2

Bottom Line: Application of extrinsic PEEP (PEEPe) reduces trigger delays and mechanical inspiratory efforts.During PSP, the NeuroSync index was 29 % at zero PEEPe and improved to 21 % at optimal PEEPe (P < 0.05).Both pre-trigger (P < 0.05) and total inspiratory mechanical efforts (P < 0.05) were consistently higher during PSP compared to PSN at same PEEPe.

View Article: PubMed Central - PubMed

Affiliation: Department of Critical Care Medicine, Nanjing Zhongda Hospital, Southeast University, School of Medicine, 87 Dingjiaqiao Street, Nanjing, 210009, China. liulingdoctor@126.com.

ABSTRACT

Introduction: Intrinsic positive end-expiratory pressure (PEEPi) is a "threshold" load that must be overcome to trigger conventional pneumatically-controlled pressure support (PSP) in chronic obstructive pulmonary disease (COPD). Application of extrinsic PEEP (PEEPe) reduces trigger delays and mechanical inspiratory efforts. Using the diaphragm electrical activity (EAdi), neurally controlled pressure support (PSN) could hypothetically eliminate asynchrony and reduce mechanical inspiratory effort, hence substituting the need for PEEPe. The primary objective of this study was to show that PSN can reduce the need for PEEPe to improve patient-ventilator interaction and to reduce both the "pre-trigger" and "total inspiratory" neural and mechanical efforts in COPD patients with PEEPi. A secondary objective was to evaluate the impact of applying PSN on breathing pattern.

Methods: Twelve intubated and mechanically ventilated COPD patients with PEEPi ≥ 5 cm H2O underwent comparisons of PSP and PSN at different levels of PEEPe (at 0 %, 40 %, 80 %, and 120 % of static PEEPi, for 12 minutes at each level on average), at matching peak airway pressure. We measured flow, airway pressure, esophageal pressure, and EAdi, and analyzed neural and mechanical efforts for triggering and total inspiration. Patient-ventilator interaction was analyzed with the NeuroSync index.

Results: Mean airway pressure and PEEPe were comparable for PSP and PSN at same target levels. During PSP, the NeuroSync index was 29 % at zero PEEPe and improved to 21 % at optimal PEEPe (P < 0.05). During PSN, the NeuroSync index was lower (<7 %, P < 0.05) regardless of PEEPe. Both pre-trigger (P < 0.05) and total inspiratory mechanical efforts (P < 0.05) were consistently higher during PSP compared to PSN at same PEEPe. The change in total mechanical efforts between PSP at PEEPe0% and PSN at PEEPe0% was not different from the change between PSP at PEEPe0% and PSP at PEEPe80%.

Conclusion: PSN abolishes the need for PEEPe in COPD patients, improves patient-ventilator interaction, and reduces the inspiratory mechanical effort to breathe.

Trial registration: Clinicaltrials.gov NCT02114567 . Registered 04 November 2013.

Show MeSH
Related in: MedlinePlus