Electrical Impedance Tomography (EIT) in a Patient Suffering from Post-COVID Syndrome with Dyspnea: A Case Report

Abstract

Background: Long-term health consequences following COVID-19 disease constitute an increasing problem worldwide. A considerable number of patients still suffer from various symptoms, most commonly dyspnea, months or even years after the acute infection. In these patients, a classical pulmonary function test often yields no significant findings. Subsequently, treating those patients is a challenge for any physician as there are currently no evidence-based treatment plans.

Case and methods: We reported the case of a 58-year-old patient who was still suffering from resting dyspnea six months after severe COVID-19 pneumonia. The dyspnea was so pronounced that the patient was supplied with home oxygen, which they used as needed. The regional distribution of ventilation in the lungs was studied twice utilizing noninvasive electrical impedance tomography (EIT). The first examination showed distinct inhomogeneities of regional ventilation, a regional ventilation delay (RVD) of 15%, and pronounced pendelluft phenomena. Seven weeks after treatment with budesonide and physical therapy, the patient reported a clear subjective improvement in complaints. Accordingly, the regional distribution of ventilation also improved.

Conclusion: Electrical impedance tomography might be a promising method to assess lung function in post-COVID patients; however, controlled and larger studies are necessary.

Keywords: distribution of ventilation; electrical impedance tomography (EIT); post-COVID syndrome.

Figure 1

Healthy volunteer: RVD image shows symmetrical ventilation to both lungs up to the marginal areas. The air first reaches the dorsal lung regions symmetrically on both sides (turquoise area) and the ventral lung regions (yellow area). Note especially the lateral symmetry and the calm distribution of the colors.

Figure 2

(a) First presentation of the patient: Tidal image shows reduced ventilation on both ventral sides and dorsal left. The enhanced color map shows a visually recognizable irregular shape of the ventilation contour similar to thorn apple forms. Recognizable is a pronounced regional ventilation delay (left dorsal; +15 %). (b) First presentation of the patient: Largely consistent distribution of ventilation and pulsatile blood flow, except for a small right ventral right region, where pulsation but no ventilation is observed.

Figure 2

(a) First presentation of the patient: Tidal image shows reduced ventilation on both ventral sides and dorsal left. The enhanced color map shows a visually recognizable irregular shape of the ventilation contour similar to thorn apple forms. Recognizable is a pronounced regional ventilation delay (left dorsal; +15 %). (b) First presentation of the patient: Largely consistent distribution of ventilation and pulsatile blood flow, except for a small right ventral right region, where pulsation but no ventilation is observed.

Figure 3

(a) The second presentation of the patient: The ventilated area is at this time slightly increased with continued low ventilation (left ventral in the tidal image). The inspiratory course is more homogeneous, with only a small extent of the regional ventilation delay (left dorsal; +3%) and a lateroventrally located region that is ventilated earlier (turquoise). (b) Second presentation of the patient: The right ventral region is now ventilated again. The distribution of ventilation and pulsatile blood flow are highly concordant.