The effects of positive end-expiratory pressure on cardiac function: a comparative echocardiography-conductance catheter study

Abstract

Background: Echocardiographic parameters of diastolic function depend on cardiac loading conditions, which are altered by positive pressure ventilation. The direct effects of positive end-expiratory pressure (PEEP) on cardiac diastolic function are unknown.

Methods: Twenty-five patients without apparent diastolic dysfunction undergoing coronary angiography were ventilated noninvasively at PEEPs of 0, 5, and 10 cmH2O (in randomized order). Echocardiographic diastolic assessment and pressure-volume-loop analysis from conductance catheters were compared. The time constant for pressure decay (τ) was modeled with exponential decay. End-diastolic and end-systolic pressure volume relationships (EDPVRs and ESPVRs, respectively) from temporary caval occlusion were analyzed with generalized linear mixed-effects and linear mixed models. Transmural pressures were calculated using esophageal balloons.

Results: τ values for intracavitary cardiac pressure increased with the PEEP (n = 25; no PEEP, 44 ± 5 ms; 5 cmH2O PEEP, 46 ± 6 ms; 10 cmH2O PEEP, 45 ± 6 ms; p < 0.001). This increase disappeared when corrected for transmural pressure and diastole length. The transmural EDPVR was unaffected by PEEP. The ESPVR increased slightly with PEEP. Echocardiographic mitral inflow parameters and tissue Doppler values decreased with PEEP [peak E wave (n = 25): no PEEP, 0.76 ± 0.13 m/s; 5 cmH2O PEEP, 0.74 ± 0.14 m/s; 10 cmH2O PEEP, 0.68 ± 0.13 m/s; p = 0.016; peak A wave (n = 24): no PEEP, 0.74 ± 0.12 m/s; 5 cmH2O PEEP, 0.7 ± 0.11 m/s; 10 cmH2O PEEP, 0.67 ± 0.15 m/s; p = 0.014; E' septal (n = 24): no PEEP, 0.085 ± 0.016 m/s; 5 cmH2O PEEP, 0.08 ± 0.013 m/s; 10 cmH2O PEEP, 0.075 ± 0.012 m/s; p = 0.002].

Conclusions: PEEP does not affect active diastolic relaxation or passive ventricular filling properties. Dynamic echocardiographic filling parameters may reflect changing loading conditions rather than intrinsic diastolic function. PEEP may have slight positive inotropic effects.

Clinical trial registration: https://ichgcp.net/clinical-trials-registry/NCT02267291 , registered 17. October 2014.

Keywords: Diastolic function; Echocardiography; End-diastolic pressure; End-systolic pressure; Mechanical ventilation; Positive end-expiratory pressure; Volume relationship.

Conflict of interest statement

The Department of Intensive Care Medicine of the Inselspital has, or has had in the past, research contracts with Abionic SA, AVA AG, CSEM SA, Cube Dx GmbH, Cyto Sorbents Europe GmbH, Edwards Lifesciences LLC, GE Healthcare, ImaCor Inc., MedImmune LLC, Orion Corporation, and Phagenesis Ltd.; and research and development/consulting contracts with Edwards Lifesciences LLC, Nestec SA, and Wyss Zurich. The money was paid into a departmental fund; Drs. Berger, Bloch, and Bachmann received no personal financial gain and declare that they have no personal conflict of interest. The Department of Intensive Care Medicine of the Inselspital has received unrestricted educational grants from the following entities for the organization of a quarterly postgraduate educational symposium, the Berner Forum for Intensive Care (until 2015): Abbott AG, Anandic Medical Systems, Astellas, AstraZeneca, Bard Medica SA, Baxter, B | Braun, CSL Behring, Covidien, Fresenius Kabi, GSK, Lilly, Maquet, MSD, Novartis, Nycomed, Orion Pharma, Pfizer, and Pierre Fabre Pharma AG (formerly known as RobaPharm). It has received unrestricted educational grants from the following entities for the organization of biannual postgraduate courses in the fields of critical care ultrasound and the management of ECMO and mechanical ventilation: Abbott AG, Anandic Medical Systems, Bard Medica SA., Bracco, Dräger Schweiz AG, Edwards Lifesciences AG, Fresenius Kabi (Schweiz) AG, Getinge Group Maquet AG, Hamilton Medical AG, Pierre Fabre Pharma AG (formerly known as RobaPharm), PanGas AG Healthcare, Pfizer AG, Orion Pharma, and Teleflex Medical GmbH. Drs. Bloechlinger, Wigger, De Marchi, Kurmann, Stalder, and Grübler have no conflict of interest to declare.

© 2022. The Author(s).

Figures

Fig. 1

Exemplary loop family from a caval occlusion maneuver with the INCA device, recorded at a PEEP level of 10 cmH2O. The loop family corresponds to the echocardiography shown in Fig. 5

Fig. 2

Mean left (a) and left transmural (b) ventricular pressures following an exponential decay model during isovolumetric relaxation, with 95% confidence intervals as dashed lines, resampled for 35 samples (140 ms). All data from all patients are included. PEEP, positive end-expiratory pressure

Fig. 3

a Left ventricular filling curves represented by diastolic ventricular pressure and PAOP, with 95% confidence intervals as dashed lines. The data were resampled for a filling period of 125 samples (500 ms). The dotted lines for early, mid- and late diastolic data points indicate the data presented in Table 4. b Transmural left ventricular filling curves Means with 95% confidence intervals as dashed lines are presented. The data were resampled to a filling period of 125 samples (500 ms). The dotted lines for early, mid- and late diastolic data points. PAOP pulmonary-artery occlusal pressure, LVP left ventricular pressure, PEEP positive end-expiratory pressure

Fig. 4

a End-systolic pressure–volume relationships (ESPVRs) for 0, 5, and 10 cmH2O PEEP, according to the mixed linear model equations in Table 4. The equation values are reported at the mean centered volume (50.4 ml), indicated by the dotted line. b End-diastolic pressure–volume relationships (EDPVRs), according to the mixed-effect generalized linear model equations in Table 7. The equation values are reported at the mean centered volume (136.2 ml), indicated by the dotted line. PEEP positive end-expiratory pressure

Fig. 5

Exemplary echocardiography tracings at a PEEP level of 10 cm H2O. The frames that correspond to the PV-Loop family in Fig. 1 are shown. The left panel shows a transmitral pulsed wave Doppler trace, the right panel a tissue Doppler tracing