What is end-expiratory occlusion testing? It is a method we can use at the bedside to determine whether a patient is fluid-responsive. We have actually known about this since 2009 when Monnet et al. explored this concept in a not-free article. The full description of the heart-lung interaction that allows this to work is beyond the scope of this post. Since then, at least 12 additional studies have been published on the matter.

If you use contents from this post in your work, please cite this post as:
Eddy J. Gutierrez, “End-Expiratory Occlusion (EEXPO) for Fluid/Volume Responsiveness”, eddyjoemd blog, October 24, 2021. Available at: http://eddyjoemd.com/end-expiratory-occlusion.

What is the end-expiratory occlusion test?

The end-expiratory occlusion test assesses whether a patient is fluid/volume responsive or not. It helps determine whether a patient will benefit from additional fluid loading during resuscitation. The test’s hemodynamic principles are based on the heart-lung interaction.

What patients can undergo end-expiratory occlusion testing?

Patients need to be mechanically ventilated and evaluated for fluid responsiveness. If they are tachypneic and unable to sustain a 15-second expiratory hold, we just can’t do it. Some studies have even pushed the expiratory hold to 30 seconds, but Gavelli’s 2020 meta-analysis showed that there was really no difference between the 15-second hold and the 30-second hold.

What should the tidal volume be?
It is unclear at this time whether having patients on 6cc/kg/IBW or 8cc/kg/IBW will provide a difference per Gavelli et al. The same group published a meta-analysis in 2020 which showed that tidal volumes less than or equal to 7 were better with an AUC of 0.96 (which is outstanding) but tidal volumes over 7cc/kg IBW was 0.89 which is still excellent.

Is there a PEEP level we should worry about?
The same 2019 Gavelli et al. paper states that patients with a PEEP between 5 and 14 should be fine. The meta-analysis written by Gavelli and his colleagues showed that PEEP settings greater than or equal to 7 perform better, but this is marginal, in my opinion. I won’t be changing PEEP settings on my patients to assess the EEXPO.

Would this work on prone patients?
Don’t try this on prone patients. It does not seem to work there.

What do we need to do at the bedside to perform an end-expiratory occlusion (EEXPO)?

While the patient is on the ventilator, you are going to perform an expiratory hold on the ventilator for 15 seconds. The patient needs to be in a clinical state where they can tolerate this 15-second expiratory hold. Simultaneously, there needs to be some sort of way to capture your favorite way of determining the change in stroke volume, cardiac output, or cardiac index. I have yet to find a study that looks at VTI in this setting. The original study by Monnet et al. used pulse-contour analysis. If your shop uses bioreactance, Gavelli has you covered with a 2021 paper that explains how to set up your device to make the EEXPO accurate.

Diagnostic Thresholds
The thresholds for a positive EEOP test are lower than the standard definitions of fluid responsiveness listed above. Gavelli’s meta-analysis states that an increase in cardiac output by approximately 5.0% (5.1 ± 0.2%) is the best diagnostic threshold to determine volume responsiveness.

Also, make sure to discuss what you’re doing with your respiratory therapist. Many of them don’t like us messing with their vents.

What have the studies found when looking at end-expiratory occlusion to predict fluid/volume responsiveness?

Monnet et al. found it better than passive leg raising, although the AUC of both was excellent at over 0.95. As a bonus, compared to other methods of assessing fluid responsiveness, they found that watching the MAP increase while performing this assessment also predicted volume responsiveness!

Can we use end-expiratory occlusion in cardiac surgery patients?

Yes, end-expiratory occlusion has been validated in cardiac surgery patients in a study by Xu et al. in July 2019. They found that a 20-second EEO is predictive of fluid responsiveness when used with the VTI with an AUC of 0.9, which is outstanding. As an aside, the authors found that using CVP to determine fluid responsiveness was a coin flip and otherwise worthless.

Okay, the EEXPO or EEOP or EOP or EEO is positive. What next?

The next step is to administer a bolus of IV fluids. The 2009 Monnet study provided patients with a 500cc bolus, which I consider appropriate for adults. Reassessments of the end-expiratory occlusion are periodically warranted because we need to remember that IV fluids are quickly extravasated.

Keywords: end-expiratory occlusion, end-expiratory occlusion test, EEO, EEXPO, EOP

Citations

Monnet X, Osman D, Ridel C, Lamia B, Richard C, Teboul JL. Predicting volume responsiveness by using the end-expiratory occlusion in mechanically ventilated intensive care unit patients. Crit Care Med. 2009 Mar;37(3):951-6. doi: 10.1097/CCM.0b013e3181968fe1. PMID: 19237902.
Link to Article NOT FREE

Gavelli F, Teboul JL, Monnet X. The end-expiratory occlusion test: please, let me hold your breath! Crit Care. 2019 Aug 7;23(1):274. doi: 10.1186/s13054-019-2554-y. PMID: 31391083; PMCID: PMC6686261.
Link to Article
Link to FULL FREE PDF

Gavelli F, Shi R, Teboul JL, Azzolina D, Monnet X. The end-expiratory occlusion test for detecting preload responsiveness: a systematic review and meta-analysis. Ann Intensive Care. 2020 May 24;10(1):65. doi: 10.1186/s13613-020-00682-8. PMID: 32449104; PMCID: PMC7246264.
Link to Article
Link to FULL FREE PDF

Si X, Song X, Lin Q, Nie Y, Zhang G, Xu H, Chen M, Wu J, Guan X. Does End-Expiratory Occlusion Test Predict Fluid Responsiveness in Mechanically Ventilated Patients? A Systematic Review and Meta-Analysis. Shock. 2020 Dec;54(6):751-760. doi: 10.1097/SHK.0000000000001545. PMID: 32433213.
Link to Article (NOT FREE)

Citations continued.

Gavelli F, Beurton A, Teboul JL, De Vita N, Azzolina D, Shi R, Pavot A, Monnet X. Bioreactance reliably detects preload responsiveness by the end-expiratory occlusion test when averaging and refresh times are shortened. Ann Intensive Care. 2021 Aug 28;11(1):133. doi: 10.1186/s13613-021-00920-7. PMID: 34453633; PMCID: PMC8401368.
Link to Article
Link to FULL FREE PDF

Xu LY, Tu GW, Cang J, Hou JY, Yu Y, Luo Z, Guo KF. End-expiratory occlusion test predicts fluid responsiveness in cardiac surgical patients in the operating theatre. Ann Transl Med. 2019 Jul;7(14):315. doi: 10.21037/atm.2019.06.58. PMID: 31475185; PMCID: PMC6694235.
Link to Article
Link to FULL FREE PDF

Messina A, Dell’Anna A, Baggiani M, Torrini F, Maresca GM, Bennett V, Saderi L, Sotgiu G, Antonelli M, Cecconi M. Functional hemodynamic tests: a systematic review and a metanalysis on the reliability of the end-expiratory occlusion test and of the mini-fluid challenge in predicting fluid responsiveness. Crit Care. 2019 Jul 29;23(1):264. doi: 10.1186/s13054-019-2545-z. PMID: 31358025; PMCID: PMC6664788.
Link to Article
Link to FULL FREE PDF

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