Time to reach a new steady state after changes of positive end expiratory pressure

Chiumello, Davide; Coppola, Silvia; Froio, Sara; Mietto, Cristina; Brazzi, Luca; Carlesso, Eleonora; Gattinoni, Luciano

doi:10.1007/s00134-013-2969-x

Cited by 64 publications

(48 citation statements)

References 17 publications

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“…On the other hand, if too much time is allowed, more time will be necessary for the full PEEP titration, and the patient will be potentially subjected to injurious ventilation due to inappropriate PEEP. Chiumello et al 104,105 conducted a physiologic study to address this question. When PEEP was decreased, P aO 2 and the other oxygenation-related variables significantly decreased within 5 min and remained unmodified in the following 55 min.…”

Section: How Long To Wait Between Changes In Peepmentioning

confidence: 99%

Recruitment Maneuvers and PEEP Titration

2015

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The injurious effects of alveolar overdistention are well accepted, and there is little debate regarding the importance of pressure and volume limitation during mechanical ventilation. The role of recruitment maneuvers is more controversial. Alveolar recruitment is desirable if it can be achieved, but the potential for recruitment is variable among patients with ARDS. A stepwise recruitment maneuver, similar to an incremental PEEP titration, is favored over sustained inflation recruitment maneuvers. Many approaches to PEEP titration have been proposed, and the best method to choose the most appropriate level for an individual patient is unclear. A PEEP level should be selected that balances alveolar recruitment against overdistention. The easiest approach to select PEEP might be according to the severity of the disease: 5-10 cm H 2 O PEEP in mild ARDS, 10 -15 cm H 2 O PEEP in moderate ARDS, and 15-20 cm H 2 O PEEP in severe ARDS. Recruitment maneuvers and PEEP should be used within the context of lung protection and not just as a means of improving oxygenation.

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Section: How Long To Wait Between Changes In Peepmentioning

confidence: 99%

Recruitment Maneuvers and PEEP Titration

2015

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“…Another argument against the explanation of EVLW changes by artefacts due to lung recruitment is that the changes in EVLW were observed rapidly both after reducing and increasing the PEEP level. Incrementing and decrementing PEEP have different impact on the time required to reach equilibrium in the respiratory system [47]. The fact that specular changes were observed after opposite PEEP changes strongly suggests that a haemodynamic mechanism may be a more plausible explanation for the observed results.…”

Section: Were the Peep-induced Changes In Evlw Due To Artefacts Of Thmentioning

confidence: 85%

Transpulmonary thermodilution detects rapid and reversible increases in lung water induced by positive end-expiratory pressure in acute respiratory distress syndrome

Gavelli

Teboul

Azzolina

et al. 2020

Ann. Intensive Care

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Purpose: It has been suggested that, by recruiting lung regions and enlarging the distribution volume of the cold indicator, increasing the positive end-expiratory pressure (PEEP) may lead to an artefactual overestimation of extravascular lung water (EVLW) by transpulmonary thermodilution (TPTD). Methods:In 60 ARDS patients, we measured EVLW (PiCCO2 device) at a PEEP level set to reach a plateau pressure of 30 cmH 2 O (HighPEEP start ) and 15 and 45 min after decreasing PEEP to 5 cmH 2 O (LowPEEP 15′ and LowPEEP 45′ , respectively). Then, we increased PEEP back to the baseline level (HighPEEP end ). Between HighPEEP start and LowPEEP 15′ , we estimated the degree of lung derecruitment either by measuring changes in the compliance of the respiratory system (Crs) in the whole population, or by measuring the lung derecruited volume in 30 patients. We defined patients with a large derecruitment from the other ones as patients in whom the Crs changes and the measured derecruited volume were larger than the median of these variables observed in the whole population. Results:Reducing PEEP from HighPEEP start (14 ± 2 cmH 2 O) to LowPEEP 15′ significantly decreased EVLW from 20 ± 4 to 18 ± 4 mL/kg, central venous pressure (CVP) from 15 ± 4 to 12 ± 4 mmHg, the arterial oxygen tension over inspired oxygen fraction (PaO 2 /FiO 2 ) ratio from 184 ± 76 to 150 ± 69 mmHg and lung volume by 144 [68-420] mL. The EVLW decrease was similar in "large derecruiters" and the other patients. When PEEP was re-increased to HighPEEP end , CVP, PaO 2 /FiO 2 and EVLW significantly re-increased. At linear mixed effect model, EVLW changes were significantly determined only by changes in PEEP and CVP (p < 0.001 and p = 0.03, respectively, n = 60). When the same analysis was performed by estimating recruitment according to lung volume changes (n = 30), CVP remained significantly associated to the changes in EVLW (p < 0.001). Conclusions:In ARDS patients, changing the PEEP level induced parallel, small and reversible changes in EVLW. These changes were not due to an artefact of the TPTD technique and were likely due to the PEEP-induced changes in CVP, which is the backward pressure of the lung lymphatic drainage.

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“…Tests of PAP increments in patients with acute respiratory distress syndrome have shown that different respiratory variables reach a balanced effect after different adjustment times [26]. Based on the assumption that the effects of PAP on segmentation might be delayed, we explored PAP's immediate effect, within seconds of start- ing, and after a 15-min exposure time at 10 cmH 2 O.…”

Section: Discussionmentioning

confidence: 99%

Positive Airway Pressure to Enhance Computed Tomography Imaging for Airway Segmentation for Virtual Bronchoscopic Navigation

et al. 2018

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Rationale: Virtual bronchoscopic navigation (VBN) guidance to peripheral pulmonary lesions is often limited by insufficient segmentation of the peripheral airways. Objectives: To test the effect of applying positive airway pressure (PAP) during CT acquisition to improve segmentation, particularly at end-expiration. Methods: CT acquisitions in inspiration and expiration with 4 PAP protocols were recorded prospectively and compared to baseline inspiratory acquisitions in 20 patients. The 4 protocols explored differences between devices (flow vs. turbine), exposures (within seconds vs. 15-min) and pressure levels (10 vs. 14 cmH₂O). Segmentation quality was evaluated with the number of airways and number of endpoints reached. A generalized mixed-effects model explored the estimated effect of each protocol. Measurements and Main Results: Patient characteristics and lung function did not significantly differ between protocols. Compared to baseline inspiratory acquisitions, expiratory acquisitions after 15 min of 14 cmH₂O PAP segmented 1.63-fold more airways (95% CI 1.07–2.48; p = 0.018) and reached 1.34-fold more endpoints (95% CI 1.08–1.66; p = 0.004). Inspiratory acquisitions performed immediately under 10 cmH₂O PAP reached 1.20-fold (95% CI 1.09–1.33; p < 0.001) more endpoints; after 15 min the increase was 1.14-fold (95% CI 1.05–1.24; p < 0.001). Conclusions: CT acquisitions with PAP segment more airways and reach more endpoints than baseline inspiratory acquisitions. The improvement is particularly evident at end-expiration after 15 min of 14 cmH₂O PAP. Further studies must confirm that the improvement increases diagnostic yield when using VBN to evaluate peripheral pulmonary lesions.

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Time to reach a new steady state after changes of positive end expiratory pressure

Abstract: We could not find a unique equilibration time for all the considered variables. However, in general, a decremental PEEP test requires far lower equilibrium time than an incremental PEEP test, suggesting a different time course for derecruitment and recruitment patterns.

Cited by 64 publications

References 17 publications

Recruitment Maneuvers and PEEP Titration

Recruitment Maneuvers and PEEP Titration

Transpulmonary thermodilution detects rapid and reversible increases in lung water induced by positive end-expiratory pressure in acute respiratory distress syndrome

Positive Airway Pressure to Enhance Computed Tomography Imaging for Airway Segmentation for Virtual Bronchoscopic Navigation

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