High <scp>PEEP</scp> levels are associated with overdistension and tidal recruitment/derecruitment in <scp>ARDS</scp> patients

Retamal, Jaime; Bugedo, Guillermo; Larsson, Anders; Bruhn, Alejandro

doi:10.1111/aas.12563

Cited by 24 publications

(21 citation statements)

References 28 publications

(36 reference statements)

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“…PEEP-induced EELV normalization is not necessarily lung protective by itself. A forced PEEP raise may lead to injurious hyperinflation of the persisting healthy lung tissue even without achieving a fully recruited lung [28]. In our model sustained hyperinflation is unlikely due to only minimal occurrence of high V A /Q ratios going along with decent changes of tidal ventilation in the non-dependent lung areas.…”

Section: Discussionmentioning

confidence: 97%

Endexpiratory lung volume measurement correlates with the ventilation/perfusion mismatch in lung injured pigs

et al. 2017

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BackgroundIn acute respiratory respiratory distress syndrome (ARDS) a sustained mismatch of alveolar ventilation and perfusion (VA/Q) impairs the pulmonary gas exchange. Measurement of endexpiratory lung volume (EELV) by multiple breath-nitrogen washout/washin is a non-invasive, bedside technology to assess pulmonary function in mechanically ventilated patients. The present study examines the association between EELV changes and VA/Q distribution and the possibility to predict VA/Q normalization by means of EELV in a porcine model.MethodsAfter approval of the state and institutional animal care committee 12 anesthetized pigs were randomized to ARDS either by bronchoalveolar lavage (n = 6) or oleic acid injection (n = 6). EELV, VA/Q ratios by multiple inert gas elimination and ventilation distribution by electrical impedance tomography were assessed at healthy state and at five different positive endexpiratory pressure (PEEP) steps in ARDS (0, 20, 15, 10, 5 cmH2O; each maintained for 30 min).ResultsVA/Q, EELV and tidal volume distribution all displayed the PEEP-induced recruitment in ARDS. We found a close correlation between VA/Q < 0.1 (representing shunt and low VA/Q units) and changes in EELV (spearman correlation coefficient −0.79). Logistic regression reveals the potential to predict VA/Q normalization (VA/Q < 0.1 less than 5%) from changes in EELV with an area under the curve of 0.89 with a 95%-CI of 0.81–0.96 in the receiver operating characteristic. Different lung injury models and recruitment characteristics did not influence these findings.ConclusionIn a porcine ARDS model EELV measurement depicts PEEP-induced lung recruitment and is strongly associated with normalization of the VA/Q distribution in a model-independent fashion. Determination of EELV could be an intriguing addition in the context of lung protection strategies.

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Section: Discussionmentioning

confidence: 97%

Endexpiratory lung volume measurement correlates with the ventilation/perfusion mismatch in lung injured pigs

et al. 2017

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“…Results from preclinical studies using animals [4, 5] and studies in humans [6, 7] support the use of positive end-expiratory pressure (PEEP), to prevent or at least minimize atelectrauma. PEEP, however, can also lead to lung injury due to overdistension [8, 9], so-called volutrauma [1]. …”

Section: Introductionmentioning

confidence: 99%

Associations between positive end-expiratory pressure and outcome of patients without ARDS at onset of ventilation: a systematic review and meta-analysis of randomized controlled trials

Neto

Filho

Cherpanath

et al. 2016

Ann. Intensive Care

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BackgroundThe aim of this investigation was to compare ventilation at different levels of positive end-expiratory pressure (PEEP) with regard to clinical important outcomes of intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) at onset of ventilation.MethodsMeta-analysis of randomized controlled trials (RCTs) comparing a lower level of PEEP with a higher level of PEEP was performed. The primary outcome was in-hospital mortality.ResultsTwenty-one RCTs (1393 patients) were eligible. PEEP ranged from 0 to 10 cmH2O and from 5 to 30 cmH2O in the lower PEEP and the higher PEEP arms of included RCTs, respectively. In-hospital mortality was not different between the two PEEP arms in seven RCTs (risk ratio [RR] 0.87; 95% confidence interval [CI] 0.62–1.21; I 2 = 26%, low quality of evidence [QoE]), as was duration of mechanical ventilation in three RCTs (standardized mean difference [SMD] 0.68; 95% CI −0.24 to 1.61; I 2 = 82%, very low QoE). PaO2/FiO2 was higher in the higher PEEP arms in five RCTs (SMD 0.72; 95% CI 0.10–1.35; I 2 = 86%, very low QoE). Development of ARDS and the occurrence of hypoxemia (2 RCTs) were lower in the higher PEEP arms in four RCTs and two RCTs, respectively (RR 0.43; 95% CI 0.21–0.91; I 2 = 56%, low QoE; RR 0.42; 95%–CI 0.19–0.92; I 2 = 19%, low QoE). There was no association between the level of PEEP and any hemodynamic parameter (four RCTs).ConclusionVentilation with higher levels of PEEP in ICU patients without ARDS at onset of ventilation was not associated with lower in-hospital mortality or shorter duration of ventilation, but with a lower incidence of ARDS and hypoxemia, as well as higher PaO2/FiO2. These findings should be interpreted with caution, as heterogeneity was moderate to high, the QoE was low to very low, and the available studies prevented us from addressing the effects of moderate levels of PEEP.Electronic supplementary materialThe online version of this article (doi:10.1186/s13613-016-0208-7) contains supplementary material, which is available to authorized users.

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“…The importance of PEEP application for maintaining adequate gas exchange while preventing ventilator-induced lung injury is especially emphasized (7,10,22,23). Many studies suggested that PEEP and the alveolar recruitment maneuver application improved ventilation-perfusion and gas exchange (7,24,25).…”

Section: Discussionmentioning

confidence: 99%

Effects of positive end-expiratory pressure on intracranial pressure during pneumoperitoneum and Trendelenburg position in a porcine model*

Bedirli¹,

Emmez²,

Ünal³

et al. 2017

Turk J Med Sci

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IntroductionRobot-assisted laparoscopic surgery has developed greatly and is becoming a standard technique for radical prostatectomy. It is widely preferred for pelvic surgeries because of its important advantages that minimize postoperative morbidity and mortality. Robotic surgeries in the pelvic region, including radical prostatectomy, rectum resection, and gynecologic procedures, usually require a steep Trendelenburg position and carbon dioxide pneumoperitoneum to secure the surgical field. Pneumoperitoneum combined with steep Trendelenburg position may cause significant changes in cardiovascular, respiratory, and neurophysiological parameters (1,2). Both the increase in abdominal pressure as a result of carbon dioxide insufflation and the head-down position have been shown to impair respiratory functions during the procedure by pushing the diaphragm upward and reducing lung volume and respiratory compliance, thus inducing atelectasis formation (3,4).Background/aim: This study was undertaken to evaluate the effects of positive end-expiratory pressure (PEEP) levels on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) and to determine the appropriate PEEP level during steep Trendelenburg position combined with pneumoperitoneum. Materials and methods:Ten pigs were included in this study. Pneumoperitoneum and Trendelenburg position were maintained and PEEP titration was initiated. Arterial pressure, heart rate, arterial blood gas, ICP, and CPP were recorded at the following time points: baseline (T0), 30 min after positioning and pneumoperitoneum (T1), PEEP 5 (T2), PEEP 10 (T3), PEEP 15 (T4), and PEEP 20 (T5).Results: MAP significantly increased at T1 compared to T0 and decreased at T4 and T5 compared to T1. ICP was 9.5 mmHg and CPP was 69.3 mmHg at T0. CO 2 insufflation and steep Trendelenburg position did not cause any significant difference in ICP and CPP. ICP increased and CPP decreased significantly at T4 and T5 compared to both T0 and T1. PaO 2 and PaO 2 /FiO 2 decreased significantly at T1 and T2 compared to T0, while both increased significantly at T3, T4, and T5 compared to T1. Conclusion:PEEP of 10 cmH 2 O was effective for providing oxygenation while preserving hemodynamic stability, ICP, and CPP in this model.

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High PEEP levels are associated with overdistension and tidal recruitment/derecruitment in ARDS patients

Abstract: In this series of patients with ARDS of mainly pulmonary origin, application of high levels of PEEP did not decrease tidal recruitment/derecruitment, but instead consistently increased tidal and maximal hyperinflation.

Cited by 24 publications

References 28 publications

Endexpiratory lung volume measurement correlates with the ventilation/perfusion mismatch in lung injured pigs

Endexpiratory lung volume measurement correlates with the ventilation/perfusion mismatch in lung injured pigs

Associations between positive end-expiratory pressure and outcome of patients without ARDS at onset of ventilation: a systematic review and meta-analysis of randomized controlled trials

Effects of positive end-expiratory pressure on intracranial pressure during pneumoperitoneum and Trendelenburg position in a porcine model*

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