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Right ventricular free wall longitudinal strain during weaning from mechanical ventilation using high-flow or conventional oxygen treatment: a pilot study

To the Editor,

Previous studies on cardiovascular system alterations due to transition from positive to negative intrathoracic pressure because of withdrawal of mechanical ventilation (MV) and resumption of spontaneous breathing focused on left ventricular function [1,2,3]. Relevant studies on right ventricular (RV) function are scarce [4,5,6]. Advancements in echocardiography, namely two-dimensional speckle-tracking echocardiography, provide novel parameters, such as RV free wall longitudinal strain (RVFWSL) that may outperform conventional measurements [7]. There is no information on RVFWSL during weaning from MV. We investigated the effect of spontaneous breathing trial (SBT), supported by high-flow oxygen treatment (HFOT), or by T-piece, on RV function in patients with prolonged MV.

Nine tracheostomized patients on MV (assist controlled mode) underwent a 30-min SBT receiving oxygen either via T-piece, or by HFOT, through tracheostomy with a flow rate of 60 L/min, followed by a washout period of 15 min on MV and 30 min with the other modality in a randomized crossover manner. Transthoracic echocardiography was performed on MV (baseline) and at the end of each SBT. Images were acquired in cine-loop format from several consecutive beats and analyzed offline (EchoPAC Version 204; GE Healthcare, Chicago, IL). A repeated-measures analysis of variance (ANOVA) was used to compare echocardiographic and physiological parameters during MV, HFOT, and T-piece. All statistical tests were two tailed; significance was defined as p < 0.05.

Fourteen SBT sessions were completed; five patients were studied on two different days with alternative sessions and four patients once. Three patients were successfully weaned from MV (Table 1). There was no significant difference in RVFWSL values measured during MV, HFOT, and T-piece (22.3%, 25.0%, and 24.7%, respectively, p = 0.415). Higher baseline RVFWSL values were associated with successful weaning (25.9 vs 20.4%, p = 0.045, Table 2).

Table 1 Baseline characteristics and outcomes of the included patients
Table 2 Echocardiographic and physiological parameters of included patients undergoing 14 sessions of spontaneous breathing trial

Our finding of a well-preserved RV response to successful SBTs, as opposed to MV, is consistent with earlier reports using pulmonary artery catheterization [4,5,6]. Since positive pressure ventilation and particularly positive end-expiratory pressure (PEEP), in most situations, reduce venous return and may increase pulmonary vascular resistance (i.e., RV afterload) [3], one would expect that MV or a modality that applies PEEP could adversely affect the RV function, compared to spontaneous breathing. Nevertheless, this may occur when PEEP induces lung overdistention [8] or in the presence of RV dysfunction [9]. We found no difference in RVFWSL between T-piece and MV, possibly due to the low level of PEEP applied during MV (Table 2). Also, we found no difference in RVFWSL between T-piece and HFOT. Although HFOT via nasal cannula generates some PEEP, HFOT via tracheostomy possibly provides lower degree of PEEP, even with the highest flow [10, 11], attributable to the fact that tracheostomy bypasses the upper airways [11, 12]. Thus, the effect of HFOT via tracheostomy on RV seems negligible. On the contrary, our finding that higher baseline RVFWSL values were associated with successful weaning suggests a role of RV function in weaning outcome. Finally, our finding that right atrial reservoir strain increased after discontinuation of MV (Table 2) possibly signifies improvement of right atrial filling secondary to decreased intrathoracic pressure.

In summary, in tracheostomized patients with prolonged MV, RVFWSL was maintained during successful SBTs, supported by HFOT or T-piece. Higher baseline RVFWSL values were associated with successful weaning.

Availability of data and materials

The datasets used and/or analyzed during the current study are available from the corresponding author on request.



High-flow oxygen treatment


Right ventricular


Right ventricular free wall longitudinal strain


Two-dimensional speckle-tracking echocardiography


Spontaneous breathing trial

SpΟ2 :

Arterial oxygen saturation measured by pulse oximetry

PaO2 :

Partial pressure of oxygen

PaCO2 :

Partial pressure of carbon dioxide

SaO2 :

Hemoglobin oxygen saturation

f :

Respiratory frequency

V T :

Tidal volume

V E :

Minute ventilation


Positive end-expiratory pressure


  1. Lemaire F, Teboul JL, Cinotti L et al (1988) Acute left ventricular dysfunction during unsuccessful weaning from mechanical ventilation. Anesthesiology 69:171–179.

    Article  CAS  PubMed  Google Scholar 

  2. Routsi C, Stanopoulos I, Kokkoris S, Sideris A, Zakynthinos S (2019) Weaning failure of cardiovascular origin: how to suspect, detect and treat—a review of the literature. Ann Intensive Care 9:6.

    Article  PubMed  PubMed Central  Google Scholar 

  3. Pinsky MR (1994) Cardiovascular effects of ventilatory support and withdrawal. Anesth Analg 79:567–576

    Article  CAS  PubMed  Google Scholar 

  4. Teboul JL, Abrouk F, Lemaire F (1988) Right ventricular function in COPD patients during weaning from mechanical ventilation. Intensive Care Med 14:483–485.

    Article  PubMed  Google Scholar 

  5. Bizouarn P, Blanloeil Y, Billaud-Debarre C (1997) Right ventricular function during weaning from mechanical ventilation after coronary artery bypass grafting: effect of volume loading. Intensive Care Med 23:1231–1236.

    Article  CAS  PubMed  Google Scholar 

  6. Schirmer U, Calzia E, Lindner KH et al (1994) Right ventricular function during weaning from respirator after coronary artery bypass grafting: comparison of two different weaning techniques. Chest 105:1352–1356.

    Article  CAS  PubMed  Google Scholar 

  7. Badano LP, Kolias TJ, Muraru D et al (2018) Standardization of left atrial, right ventricular, and right atrial deformation imaging using two-dimensional speckle tracking echocardiography: a consensus document of the EACVI/ASE/Industry Task Force to standardize deformation imaging. Eur Heart J Cardiovasc Imaging 19:591–600.

    Article  PubMed  Google Scholar 

  8. Jardin F, Brun-Ney D, Hardy A, Aegerter P, Beauchet A, Bourdarias J-P (1991) Combine thermodilution and two-dimensional echocardiographic evaluation of right ventricular function during respiratory support with PEEP. Chest 99:162–168.

    Article  CAS  PubMed  Google Scholar 

  9. Schulman DS, Biondi JW, Matthay RA, Barash PG, Zaret BL, Soufer R (1988) Effect of positive end-expiratory pressure on right ventricular performance. Importance of baseline right ventricular function. Am J Med 84:57–67.

    Article  CAS  PubMed  Google Scholar 

  10. Thomas M, Joshi R, Cave G (2021) How much PEEP does high flow deliver via tracheostomy? A literature review and benchtop experiment. Crit Care Res Pract.

    Article  PubMed  PubMed Central  Google Scholar 

  11. Stripoli T, Spadaro S, Di Mussi R et al (2019) High-flow oxygen therapy in tracheostomized patients at high risk of weaning failure. Ann Intensive Care 9:4.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  12. Natalini D, Grieco DL, Santantonio MT et al (2019) Physiological effects of high-flow oxygen in tracheostomized patients. Ann Intensive Care 9:114.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

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This work was presented in the 36th Annual Congress of the European Society of Intensive Care Medicine 2023, Intensive Care Medicine Experimental 2023;11:72, p 640 (Poster Νο. 001407).


No author received funding for this study.

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Authors and Affiliations



IIS and CR conceived the study and designed the trial. EX and AK performed the echocardiographic examinations and offline image analysis and interpretation of data. EX, IIS, and CR drafted and revised the manuscript. AK and AK contributed substantially to the revision of the manuscript. CR takes responsibility for the paper as a whole. All authors read and approved the final manuscript.

Corresponding author

Correspondence to Christina Routsi.

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The study was approved by the institutional review board (approval number: 112/24-3-2022), and informed consent was obtained from each patient or the patient’s next of kin.

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No identifiable data from individual patients are included in this paper.

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The authors declare that they have no competing interests.

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Xourgia, E., Koronaios, A., Kotanidou, A. et al. Right ventricular free wall longitudinal strain during weaning from mechanical ventilation using high-flow or conventional oxygen treatment: a pilot study. Ultrasound J 16, 17 (2024).

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