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. 2021 Jun;36(6):696-703.
doi: 10.1177/08850666211000601. Epub 2021 Mar 11.

Ventilated Patients With COVID-19 Show Airflow Obstruction

Vikas S Koppurapu  1 , Maksym Puliaiev  1 , Kevin C Doerschug  1 , Gregory A Schmidt  1
Affiliations

Ventilated Patients With COVID-19 Show Airflow Obstruction

Vikas S Koppurapu et al. J Intensive Care Med. 2021 Jun.

Abstract

Objective: Many patients with coronavirus disease 2019 (COVID-19) need mechanical ventilation secondary to acute respiratory distress syndrome. Information on the respiratory system mechanical characteristics of this disease is limited. The aim of this study is to describe the respiratory system mechanical properties of ventilated COVID-19 patients.

Design, setting, and patients: Patients consecutively admitted to the medical intensive care unit at the University of Iowa Hospitals and Clinics in Iowa City, USA, from April 19 to May 1, 2020, were prospectively studied; final date of follow-up was May 1, 2020.

Measurements: At the time of first patient contact, ventilator information was collected including mode, settings, peak airway pressure, plateau pressure, and total positive end expiratory pressure. Indices of airflow resistance and respiratory system compliance were calculated and analyzed.

Main results: The mean age of the patients was 58 years. 6 out of 12 (50%) patients were female. Of the 21 laboratory-confirmed COVID-19 patients on invasive mechanical ventilation, 9 patients who were actively breathing on the ventilator were excluded. All the patients included were on volume-control mode. Mean [±standard deviation] ventilator indices were: resistive pressure 19 [±4] cmH2O, airway resistance 20 [±4] cmH2O/L/s, and respiratory system static compliance 39 [±16] ml/cmH2O. These values are consistent with abnormally elevated resistance to airflow and reduced respiratory system compliance. Analysis of flow waveform graphics revealed a pattern consistent with airflow obstruction in all patients.

Conclusions: Severe respiratory failure due to COVID-19 is regularly associated with airflow obstruction.

Keywords: COVID-19; airway resistance; atypical; mechanical ventilation; obstruction; respiratory mechanics.

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Conflict of interest statement

Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article. Dr. Schmidt reports financial relationship in the form of royalty with the following entities: McGraw-Hill, UpToDate, and Elsevier.

Figures

Figure 1.
Figure 1.
Representative image of ventilator waveforms. The expiratory flow waveform demonstrates rapid flow deceleration followed by slow return to baseline (arrows). Also note the abnormal Ppeak minus Pplat (double-headed arrow and right-hand side of the pane).
Figure 2.
Figure 2.
Representative image of ventilator waveforms. Expiratory flow present at end-expiration (circles).
Figure 3.
Figure 3.
Representative image of ventilator waveforms. Intrinsic PEEP unmasked by manual expiratory hold maneuver (dotted rectangle; circle at bottom of the pane represents operator set PEEP and rectangle on the right-hand side of the pane represents PEEPtot).
See this image and copyright information in PMC

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