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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.

ABSTRACT: 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.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.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%.PSN abolishes the need for PEEPe in COPD patients, improves patient-ventilator interaction, and reduces the inspiratory mechanical effort to breathe.Clinicaltrials.gov NCT02114567 . Registered 04 November 2013.

SUBMITTER: Liu L

PROVIDER: S-EPMC4487968 | biostudies-literature | 2015 Jun

REPOSITORIES: biostudies-literature

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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 Ling L Xia Feiping F Yang Yi Y Longhini Federico F Navalesi Paolo P Beck Jennifer J Sinderby Christer C Qiu Haibo H

Critical care (London, England) 20150609

<h4>Introduction</h4>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 ...[more]

PMID: 26059238

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Project description:Airway clearance techniques include positive expiratory pressure, commonly used in our clinical practice, and a recently introduced temporary positive expiratory pressure device called UNIKO®. It is unclear which one provides the best benefit to patients.The aim of this observational 4-year study was to retrospectively compare the efficacy of and specific indications for temporary positive expiratory pressure compared to positive expiratory pressure in a standard rehabilitation program.We retrospectively collected data from 162 subjects (107 males, mean age 70±9 years, 97 with primary diagnosis of chronic obstructive pulmonary disease, 65 with bronchiectasis), 51 treated with temporary positive expiratory pressure and 111 with positive expiratory pressure.Subjects showed significant improvement in ratio of partial pressure arterial oxygen and fraction of inspired oxygen (p<0.001), forced vital capacity, forced expiratory volume in one second, peak expiratory flow, arterial oxygen saturation, and partial pressure arterial oxygen with no significant difference between positive expiratory pressure and temporary positive expiratory pressure groups apart from forced expiratory flow, which increased only in the positive expiratory pressure group. Evaluating specific subgroups, temporary positive expiratory pressure was more effective than positive expiratory pressure in improving gas transfer in subjects with emphysema and in those on oxygen therapy, as the effective supplement oxygen flow decreased significantly (p=0.034 and 0.046 respectively for temporary positive expiratory pressure vs. positive expiratory pressure). In subjects on mechanical ventilation, positive expiratory pressure was superior to temporary positive expiratory pressure in increasing forced expiratory flow (p=0.018).The physiological parameters of both groups improved significantly and similarly. Subgroup analysis suggests that temporary positive expiratory pressure could provide some advantage to subjects with emphysema and those on oxygen therapy, while positive expiratory pressure would benefit patients on mechanical ventilation. Randomized clinical trials are necessary to confirm our preliminary results indicating that different subgroups/phenotypes can benefit more from one type of treatment.

Project description:BackgroundPositive end-expiratory pressure (PEEP) has been demonstrated to decrease ventilator-induced lung injury in patients under mechanical ventilation (MV) for acute respiratory failure. Recently, some studies have proposed some beneficial effects of PEEP in ventilated patients without lung injury. The influence of PEEP on respiratory mechanics in children is not well known. Our aim was to determine the effects on respiratory mechanics of setting PEEP at 5 cmH2O in anesthetized healthy children.MethodsPatients younger than 15 years old without history of lung injury scheduled for elective surgery gave informed consent and were enrolled in the study. After usual care for general anesthesia, patients were placed on volume controlled MV. Two sets of respiratory mechanics studies were performed using inspiratory and expiratory breath hold, with PEEP 0 and 5 cmH2O. The maximum inspiratory and expiratory flow (QI and QE) as well as peak inspiratory pressure (PIP), plateau pressure (PPL) and total PEEP (tPEEP) were measured. Respiratory system compliance (CRS), inspiratory and expiratory resistances (RawI and RawE) and time constants (KTI and KTE) were calculated. Data were expressed as median and interquartile range (IQR). Wilcoxon sign test and Spearman's analysis were used. Significance was set at P < 0.05.ResultsWe included 30 patients, median age 39 (15-61.3) months old, 60% male. When PEEP increased, PIP increased from 12 (11,14) to 15.5 (14,18), and CRS increased from 0.9 (0.9,1.2) to 1.2 (0.9,1.4) mL·kg- 1·cmH2O- 1; additionally, when PEEP increased, driving pressure decreased from 6.8 (5.9,8.1) to 5.8 (4.7,7.1) cmH2O, and QE decreased from 13.8 (11.8,18.7) to 11.7 (9.1,13.5) L·min- 1 (all P < 0.01). There were no significant changes in resistance and QI.ConclusionsAnalysis of respiratory mechanics in anesthetized healthy children shows that PEEP at 5 cmH2O places the respiratory system in a better position in the P/V curve. A better understanding of lung mechanics may lead to changes in the traditional ventilatory approach, limiting injury associated with MV.

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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.

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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.

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