Bedside assessment of the effects of positive end-expiratory pressure on lung inflation and recruitment by the helium dilution technique and electrical impedance tomography

Mauri, Tommaso; Eronia, Nilde; Turrini, Cecilia; Battistini, M.; Grasselli, Giacomo; Rona, Roberto; Volta, Carlo Alberto; Bellani, Giacomo; Pesenti, Antonio

doi:10.1007/s00134-016-4467-4

Cited by 83 publications

(97 citation statements)

References 44 publications

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“…However, it reflects more a better overall aeration of the lung between two levels of PEEP than the opening of previously gasless tissue. Accordingly, the CT scan-EIT correlation in assessing the recruitability is quite poor (52), while it is better if compared with gas-assessed recruitability (53). It is worth re-emphasizing that the gas method preferentially measures the better inflation at higher PEEP of previously inflated units at lower PEEP than the opening of previously collapsed units (35) (60).…”

Section: Patient Characterizationmentioning

confidence: 99%

Positive end-expiratory pressure: how to set it at the individual level

Gattinoni¹,

Collino²,

Maiolo³

et al. 2017

Ann. Transl. Med.

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Abstract:The positive end-expiratory pressure (PEEP), since its introduction in the treatment of acute respiratory failure, up to the 1980s was uniquely aimed to provide a viable oxygenation. Since the first application, a large debate about the criteria for selecting the PEEP levels arose within the scientific community. Lung mechanics, oxygen transport, venous admixture thresholds were all proposed, leading to PEEP recommendations from 5 up to 25 cmH 2 O. Throughout this period, the main concern was the hemodynamics. This paradigm changed during the 1980s after the wide acceptance of atelectrauma as one of the leading causes of ventilator induced lung injury. Accordingly, the PEEP aim shifted from oxygenation to lung protection. In this framework, the prevention of lung opening and closing became an almost unquestioned dogma. Consequently, as PEEP keeps open the pulmonary units opened during the previous inspiratory phase, new methods were designed to identify the 'optimal' PEEP during the expiratory phase.The open lung approach requires that every collapsed unit potentially openable is opened and maintained open. The methods to assess the recruitment are based on imaging (computed tomography, electric impedance tomography, ultrasound) or mechanically-driven gas exchange modifications. All the latest assume that whatever change in respiratory system compliance is due to changes in lung compliance, which in turn is uniquely function of the recruitment. Comparative studies, however, showed that the only possible approach to measure the amount of collapsed tissue regaining inflation is the CT scan. In fact, all the other methods estimate as recruitment the gas entry in pulmonary units already open at lower PEEP, but increasing their compliance at higher PEEP. Since higher PEEP is usually more indicated (also for oxygenation) when the recruitability is higher, as occurs with increasing severity, a meaningful PEEP selection requires the assessment of recruitment. The Berlin definition may help in this assessment.

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Section: Patient Characterizationmentioning

confidence: 99%

Positive end-expiratory pressure: how to set it at the individual level

Gattinoni¹,

Collino²,

Maiolo³

et al. 2017

Ann. Transl. Med.

View full text Add to dashboard Cite

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“…Indeed, recent studies and reviews have reinforced the seminal role of ultrasound in general, and transesophageal echocardiography in particular, in the diagnostic workup and monitoring of ARDS patients [13]. The direct assessment of pulmonary vascular dysfunction at the bedside is still a clinical challenge, but emerging techniques like electric impedance tomography may provide informative data on regional distribution of lung perfusion in the near future [14].…”

mentioning

confidence: 99%

Focus on ARDS

2017

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Since 1967, when first described, ARDS has been widely recognized as a major health problem worldwide, carrying a high morbidity and mortality [1][2][3]. This focus editorial summarizes recent advances about the incidence, pathophysiology, right ventricular dysfunction, and mortality of ARDS.Despite the attempt to homogenize its definition following the publication of the Berlin criteria, there is still a high heterogeneity in the epidemiology of ARDS across the world [3]. Indeed, estimates of the incidence of ARDS are highly variable, ranging from less than 2 to more than 70 cases per 100,000 person-years, with the most recent study on the topic suggesting a higher incidence in Europe, North America, and Oceania compared to South America, Asia, and Africa [2,3]. However, it is important to emphasize that this scenario could only reflect the under-recognition of this syndrome [3]. Recent reports suggest a progressive decline of the incidence of ARDS. In a study conducted in Rochester, cases fell by half between 2001 and 2008 while mortality remained stable [4]. Nearly all of the reduction in the incidence was observed in hospital-acquired ARDS, suggesting that ARDS could be prevented through strategies addressing its related risk factors [4,5]. However, in some instances, patients meeting the Berlin criteria for ARDS lack exposure to common risk factors [6]. It was recently reported that the prevalence of patients with ARDS but without common risk factors was as high as 7.5% [6]. According to medical history, bronchoalveolar lavage fluid cytology, and chest computed tomography (CT) scan patterns, four etiological categories were identified in this group of patients: immune, drug-induced, malignant, and idiopathic [6]. The overall ICU mortality rate was higher in patients lacking common risk factors as compared to their counterparts, even after adjustment for potential confounding factors [6].It is already well known that ventilator-induced lung injury contributes to ARDS-associated mortality [2,3]. Recently, some biological markers have been proposed as potential biomarkers of ARDS, such as the soluble form of the receptor for advanced glycation end-products (sRAGE). This biomarker is a transmembrane receptor that can bind multiple ligands resulting in intracellular signaling, leading to activation of the proinflammatory transcription factor nuclear factor κB [7]. Plasma levels of sRAGE could change according to ventilator settings in ARDS patients, as recently suggested by a study describing a significant decrease of sRAGE 1 h after a recruitment maneuver followed by an increase toward baseline values 4 h after the maneuver [7]. It has also been shown that sRAGE is higher in non-survivors than survivors in early pediatric ARDS and strongly correlated with number of non-pulmonary organ failures [8]. Other biomarkers of endothelial injury are also investigated in ARDS patients. Higher levels of circulating endothelial cells were found in the blood of patients with moderate-to-severe ARDS as compared to those with...

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“…This can be estimated by simultaneous measurement of esophageal pressure (Pes) and gastric pressure (Pga) as surrogates for the pleural and abdominal pressures, respectively. Recently, recommendations for the use of Pes monitoring in ICU patients were published [16, 17]. Although no reference values for Pdi are available for critically ill patients, monitoring will prevent unwanted periods of diaphragm inactivity due to over‐assist in partially supported modes.…”

Section: Clinical Implications Of Current Knowledgementioning

confidence: 99%