Intrinsic PEEP monitored in the ventilated ARDS patient with a mathematical method

Eberhard, L.; Guttmann, J.; Wolff, G.; Bertschmann, W; Minzer, A.; Kohl, H. J.; Zeravik, J.; Adolph, M.; Eckart, J.

doi:10.1152/jappl.1992.73.2.479

Cited by 41 publications

(28 citation statements)

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“…Consequently, when using the VDSCM, Ers,dyn=(E 1 +E 2 VT). PEEPi was calculated as the difference between Po and the minimum Paw [11,19,20] and was minimal in all patients (0.24±0.00 cmH 2 O). The %E 2 was calculated as (100E 2 VT)/(E 1 +E 2 VT) [11], and Pel,dyn calculated as (E 1 +E 2 VT)VT+Po.…”

Section: Discussionmentioning

confidence: 99%

Measurement of overinflation by multiple linear regression analysis in patients with acute lung injury

Bersten¹

1998

Eur Respir J

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aaAcute lung injury (ALI) results in an increase in permeability, recruitment of neutrophils and impairment of the surfactant system. Although increased permeability in patients with the acute respiratory distress syndrome (ARDS) is evenly distributed across the lung [1], regional lung inflation is markedly heterogeneous [2,3]. Increased lung weight tends to collapse a dependent lung, while nondependent lung is more normally aerated. Since a relatively small lung is ventilated, excessive tidal volumes could overdistend some alveoli and produce further lung injury.In order to prevent overdistension, current recommendations target ventilatory plateau pressures <30-35 cmH 2 O [4,5], since total lung capacity is normally achieved at this level of transalveolar pressure. However, the end-inspiratory lung volume (VEI), rather than the airway pressure (Paw), appears to determine whether lung injury occurs [6]. This was confirmed in a recent clinical study where up to 90% of ARDS patients showed evidence of overinflation below a plateau pressure of 35 cmH 2 O [7].Static volume-pressure curve analysis has been used to define lung overinflation, with the upper inflection point denoting a sudden increase in elastance with further inflation. However, static techniques are not widely used. Since a prolonged pause is needed for equilibration of gas flow and respiratory muscle activity may also result in an unstable end-expiratory lung volume (EELV), the subject must be paralysed. If a super-syringe technique is used allowance must be made for the continuing gas exchange [8] and patients may develop hypoxaemia. Finally, respiratory mechanics are only described at a single point in a continually evolving process.Dynamic volume-pressure curve analysis offers online, potentially continuous, measurements that do not interfere with ventilation and produce a "functional" description of lung mechanics [9]. Dynamic data may also reflect the contribution of heterogeneous time constants to lung overinflation. At a given respiratory rate short time constant lung units will receive proportionately more ventilation than long time constant lung units, possibly contributing to regional overinflation [10]. This effect would not be detected by static volume-pressure curve analysis, but would contribute to both dynamic curve changes and possibly to ventilator-induced lung injury.Models for estimating overinflation from dynamic volume-pressure curves, by partitioning dynamic respiratory elastance (Ers,dyn) into volume-independent (E 1 ) and volume-dependent (E 2 ) components [11][12][13], have only recently been described. However, this technique has not been Measurement of overinflation by multiple linear regression analysis in patients with acute lung injury. A.D. Bersten. ERS Journals Ltd 1998.ABSTRACT: Strategies to optimize alveolar recruitment and prevent lung overinflation are central to ventilatory management of patients with acute lung injury (ALI). The recent description of overinflation using multilinear regression analysis of airway...

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Section: Discussionmentioning

confidence: 99%

Measurement of overinflation by multiple linear regression analysis in patients with acute lung injury

Bersten¹

1998

Eur Respir J

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“…Following the procedure of PEPE and MARINI [20], the intrinsic positive end-expiratory pressure (PEEPi) was measured with the end-expiratory occlusion manoeuvre, as described in detail by EBERHARD et al [21]. The gas volume (VRET) retained by dynamic hyperinflation [22] was determined by numeric integration of the flow expired after the occlusion manoeuvre [21].…”

Section: Methodsmentioning

confidence: 99%

Time constant/volume relationship of passive expiration in mechanically ventilated ARDS patients

Guttmann¹,

Eberhard²,

Fabry³

et al. 1995

Eur Respir J

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T Ti im me e c co on ns st ta an nt t/ /v vo ol lu um me e r re el la at ti io on ns sh hi ip p o of f p pa as ss si iv ve e e ex xp pi ir ra at ti io on n i in n m me ec ch ha an ni ic ca al ll ly y v ve en nt ti il la at te ed d A AR RD DS S p pa at ti ie en nt ts s The mean values of τE for each volume slice did not differ significantly throughout expiration, averaging 690±218 ms (mean±SD of five slices and 12 patients). We show that the flow-dependent resistance of the endotracheal tube (RETT) is mainly responsible for the observed time constant homogeneity.We conclude that in ARDS patients during uninterrupted mechanical ventilation the time constants of passive expiration are markedly modified by the flow-dependent resistance of the endotracheal tube (RETT), and also by the external resistance of tubing and ventilator (REX). RETT and REX render τE about three times larger than the time constant of the patient's respiratory system alone.

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“…where ∆P aw_tot represents the total airway pressure, V is the lung volume, E is the respiratory elastance, Q is the airflow rate, R is the respiratory resistance and P0 is the offset pressure which is a combination of applied PEEP and intrinsic PEEP [18,19].…”

Section: Methodsmentioning

confidence: 99%

Dynamic functional residual capacity can be estimated using a stress–strain approach

Sundaresan

Chase

Hann

2011

Computer Methods and Programs in Biomedicine

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Intrinsic PEEP monitored in the ventilated ARDS patient with a mathematical method

Cited by 41 publications

References 0 publications

Measurement of overinflation by multiple linear regression analysis in patients with acute lung injury

Measurement of overinflation by multiple linear regression analysis in patients with acute lung injury

Time constant/volume relationship of passive expiration in mechanically ventilated ARDS patients

Dynamic functional residual capacity can be estimated using a stress–strain approach

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