Hyperventilation syndrome in patients with prolonged dyspnea after a mild COVID-19 infection

15 May 2023
Introduction: Both post-COVID-19-syndrome and hyperventilation syndrome (HVS) are disputed concepts with a wide range of symptoms, where increased dyspnea is among the most common symptoms in both syndromes. The long-term prognosis for patients with post-COVID-19-syndrome is largely unknown. The Nijmegen questionnaire was suggested before the COVID-19 pandemic as a self-assessment score to detect HVS, with higher scores meaning more symptoms. A low end-tidal partial pressure of CO2 (PETCO2) despite normal diffusing capacity of the lungs for carbon monoxide (DLCO) has been suggested as a physiological marker of HVS, indicating an inappropriate increase of ventilation even at rest. Methods: Nineteen subjects (12 women, 7 men) aged 24-61 years (median 45 years) with laboratory test verified mild (non-hospitalized) infection with COVID-19 and subsequent increased dyspnea for ≥3 months, were included. All were never-smokers without any previous airway disease. Subjects performed 6-minute walk test (6MWT), spirometry, DLCO test, measurement of PETCO2 and were assessed with the Nijmegen questionnaire at inclusion. A second 6MWT and Nijmegen scoring was performed 6 months after inclusion. Results: Eighteen subjects had PETCO2 at rest below the normal range, one subject had a normal PETCO2 (median for all subjects 83% of predicted). All had a normal spirometry and test of DLCO. Median total Nijmegen score at inclusion was 22.5 (range 5-49). Walking distance on 6MWT was negatively correlated with Nijmegen questionnaire score (r=-0.67, p=0.02). Nijmegen scores had not decreased at the 6 months follow-up (median 26) and the 6MWT showed unchanged walking distance (median 575 m vs. 540 m). Discussion: Prolonged increased dyspnea after mild COVID-19 infection could be due to an HVS. The previously suggested HVS self-assessment score Nijmegen seems to correlate with physical capacity as measured by a 6MWT. Our subjects did not improve in self-assessed symptoms or physical capacity over a period of 6 months.

Resource information

Respiratory conditions
  • COVID-19
Respiratory topics
  • Co-morbidities
Type of resource
Munich 2023
Henning Stenberg1, Ellen Tufvesson2, Ida Dalene Skarping3 1Center for Primary Health Care Research, Lund University, Malmö, Sweden, 2Department of Respiratory Medicine and Allergology, Lund University, Lund, Sweden, 3Department of Clinical Physiology and Nuclear Medicine, Lund University, Lund, Sweden