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Observational Study
. 2023 Aug 1;51(8):1023-1032.
doi: 10.1097/CCM.0000000000005848. Epub 2023 Mar 27.

Intrapulmonary and Intracardiac Shunts in Adult COVID-19 Versus Non-COVID Acute Respiratory Distress Syndrome ICU Patients Using Echocardiography and Contrast Bubble Studies (COVID-Shunt Study): A Prospective, Observational Cohort Study

Vincent I Lau  1 , Graham D Mah  1 , Xiaoming Wang  2 , Leon Byker  1 , Andrea Robinson  1 , Lazar Milovanovic  1 , Aws Alherbish  1   3 , Jeffrey Odenbach  1   4 , Cristian Vadeanu  5 , David Lu  6 , Leo Smyth  7 , Mitchell Rohatensky  7 , Brian Whiteside  5 , Phillip Gregoire  1 , Warren Luksun  1   8 , Sean van Diepen  1   3 , Dustin Anderson  1   9 , Sanam Verma  1   3 , Jocelyn Slemko  1 , Peter Brindley  1 , Demetrios J Kustogiannis  1 , Michael Jacka  1 , Andrew Shaw  10 , Matt Wheatley  11 , Jonathan Windram  3 , Dawn Opgenorth  1 , Nadia Baig  1 , Oleksa G Rewa  1   12 , Sean M Bagshaw  1   12 , Brian M Buchanan  1
Affiliations
Observational Study

Intrapulmonary and Intracardiac Shunts in Adult COVID-19 Versus Non-COVID Acute Respiratory Distress Syndrome ICU Patients Using Echocardiography and Contrast Bubble Studies (COVID-Shunt Study): A Prospective, Observational Cohort Study

Vincent I Lau et al. Crit Care Med. .

Abstract

Objectives: Studies have suggested intrapulmonary shunts may contribute to hypoxemia in COVID-19 acute respiratory distress syndrome (ARDS) with worse associated outcomes. We evaluated the presence of right-to-left (R-L) shunts in COVID-19 and non-COVID ARDS patients using a comprehensive hypoxemia workup for shunt etiology and associations with mortality.

Design: Prospective, observational cohort study.

Setting: Four tertiary hospitals in Edmonton, Alberta, Canada.

Patients: Adult critically ill, mechanically ventilated, ICU patients admitted with COVID-19 or non-COVID (November 16, 2020, to September 1, 2021).

Interventions: Agitated-saline bubble studies with transthoracic echocardiography/transcranial Doppler ± transesophageal echocardiography assessed for R-L shunts presence.

Measurements and main results: Primary outcomes were shunt frequency and association with hospital mortality. Logistic regression analysis was used for adjustment. The study enrolled 226 patients (182 COVID-19 vs 42 non-COVID). Median age was 58 years (interquartile range [IQR], 47-67 yr) and Acute Physiology and Chronic Health Evaluation II scores of 30 (IQR, 21-36). In COVID-19 patients, the frequency of R-L shunt was 31 of 182 COVID patients (17.0%) versus 10 of 44 non-COVID patients (22.7%), with no difference detected in shunt rates (risk difference [RD], -5.7%; 95% CI, -18.4 to 7.0; p = 0.38). In the COVID-19 group, hospital mortality was higher for those with R-L shunt compared with those without (54.8% vs 35.8%; RD, 19.0%; 95% CI, 0.1-37.9; p = 0.05). This did not persist at 90-day mortality nor after adjustment with regression.

Conclusions: There was no evidence of increased R-L shunt rates in COVID-19 compared with non-COVID controls. R-L shunt was associated with increased in-hospital mortality for COVID-19 patients, but this did not persist at 90-day mortality or after adjusting using logistic regression.

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Conflict of interest statement

Dr. Lau’s institution received funding from the University Hospital Foundation, the Royal Alexandra Hospital Foundation, and the Covenant Health Foundation. Dr. Shaw received funding from Edwards Lifesciences, Novartis, and Astellas. Dr. Opgenorth disclosed that she is an employee of the University of Alberta. Dr. Bagshaw received funding from Baxter and BioPorto; he is supported by a Canada Research Chair in Critical Care Outcomes and Systems Evaluation. The remaining authors have disclosed that they do not have any potential conflicts of interest.

Figures

Figure 1.
Figure 1.
Strengthening the Reporting of Observational Studies in Epidemiology diagram flowchart for hypoxemia workup assessing shunt presence. ARDS = acute respiratory distress syndrome, MRP = most responsible physician, TCD = transcranial Doppler, TEE = transesophageal echocardiography, TTE = transthoracic echocardiography.
Figure 2.
Figure 2.
Kaplan-Meier curves.
See this image and copyright information in PMC

References

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