Baseline hypocapnia is associated with intubation in COVID-19 diagnosed patients

  1. Athanasios Gounidis
  2. Alexandros P. Evangeliou
  3. Christina Kloura
  4. Evangelia Manganari
  5. Christiana Parisi
  6. Michalis Kourtidis
  7. Georgios Kotronis
  8. Martha Apostolopoulou
  9. Fani Apostolidou-Kiouti

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Abstract

Introduction

Hypocapnia may be one of the several factors predefining the need for intubation of patients needing hospitalization for COVID-19 pneumonia.

Methods

A retrospective evaluation of patient files hospitalized for COVID-19 pneumonia from October 2020 until January 2021. Univariate and multivariate regression was used, as well as a multinomial regression to account for multiple endpoints (discharge, intubation, death).

Results

Hypocapnia was strongly associated with intubation (OR: 0.86, 95% CI: 0.76, 0.97). Additionally, last pCO2 (OR: 1.08, 95% CI: 1.01, 1.16), baseline FiO2 (OR: 1.05, 95% CI: 1.03, 1.07) as well as last FiO2 (OR: 1.21, 95% CI: 1.11, 1.46), total severity score on admission (OR: 1.18, 95% CI: 1.03, 1.37) and last pO2 (OR: 0.89, 95% CI: 0.85, 0.92) were found to have a significant impact on intubation. Incorporation of deceased patients withheld the negative association with pCO2 levels (OR: 0.88, 95% CI: 0.78, 0.98).

Conclusion

The dissociation between respiratory failure and a clinically comfortable patient is partly due to decreased carbon dioxide levels and clinicians should bare it in mind when handling patients with COVID-19 pneumonia. Hypocapnia seems to be a determinant factor of intubation in patients with COVID-19 pneumonia in this study.

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  1. ScreenIT

    SciScore for 10.1101/2021.11.19.21266581: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Ethicsnot detected.
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    No key resources detected.

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    Several limitations are present in this observational study. The relatively small number of events, despite fulfilling the a priori power calculation to detect a difference, does not allow for generalization as a prognostic factor for intubation. This was a single centre study, with a limited number of cases; therefore caution is necessary when attempting to generalize the results. Future multicenter clinical trials included larger number of subjects are awaited to provide data about this prognostic factor. Another important constraint was the patient inflow, as the major proportion of patients were transferred from other hospitals, days after symptom onset and various stages of disease, having received various therapeutic agents. The baseline measurements of our study may not be homogenous with respect to days since symptom onset and treatment naïveté or nosocomial infection; in a larger sample this heterogeneity would yield a much more robust result. Another important constraint is the lack of evaluation for observer agreement for the radiological findings of chest computed tomography. Our data was not sufficient to run such analyses; as a result, this important parameter of disease severity could not be reliably assessed as a contributing factor. Despite the limitations, there are several strengths in the current comparison. The most important is the inclusion of all admitted patients, regardless of comorbidities or previous respiratory disease. This allows for generalizat...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    Results from scite Reference Check: We found no unreliable references.

    About SciScore

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  2. Version published to 10.1101/2021.11.19.21266581v1 on medRxiv