tetano
Editor, Senior Moderator
Physiol Rep
. 2021 Feb;9(4):e14748.
doi: 10.14814/phy2.14748.
Lung diffusing capacity for nitric oxide and carbon monoxide following mild-to-severe COVID-19
Giovanni Barisione[SUP] 1 [/SUP], Vito Brusasco[SUP] 2 [/SUP]
Affiliations
Abstract
A decreased lung diffusing capacity for carbon monoxide (DL[SUB]CO[/SUB] ) has been reported in a variable proportion of subjects over the first 3 months of recovery from severe coronavirus disease 2019 (COVID-19). In this study, we investigated whether measurement of lung diffusing capacity for nitric oxide (DL[SUB]NO[/SUB] ) offers additional insights on the presence and mechanisms of gas transport abnormalities. In 94 subjects, recovering from mild-to-severe COVID-19 pneumonia, we measured DL[SUB]NO[/SUB] and DL[SUB]CO[/SUB] between 10 and 266 days after each patient was tested negative for severe acute respiratory syndrome coronavirus 2. In 38 subjects, a chest computed tomography (CT) was available for semiquantitative analysis at six axial levels and automatic quantitative analysis of entire lungs. DL[SUB]NO[/SUB] was abnormal in 57% of subjects, independent of time of lung function testing and severity of COVID-19, whereas standard DL[SUB]CO[/SUB] was reduced in only 20% and mostly within the first 3 months. These differences were not associated with changes of simultaneous DL[SUB]NO[/SUB] /DL[SUB]CO[/SUB] ratio, while DL[SUB]CO[/SUB] /V[SUB]A[/SUB] and DL[SUB]NO[/SUB] /V[SUB]A[/SUB] were within normal range or slightly decreased. DL[SUB]CO[/SUB] but not DL[SUB]NO[/SUB] positively correlated with recovery time and DL[SUB]CO[/SUB] was within the normal range in about 90% of cases after 3 months, while DL[SUB]NO[/SUB] was reduced in more than half of subjects. Both DL[SUB]NO[/SUB] and DL[SUB]CO[/SUB] inversely correlated with persisting CT ground glass opacities and mean lung attenuation, but these were more frequently associated with DL[SUB]NO[/SUB] than DL[SUB]CO[/SUB] decrease. These data show that an impairment of DL[SUB]NO[/SUB] exceeding standard DL[SUB]CO[/SUB] may be present during the recovery from COVID-19, possibly due to loss of alveolar units with alveolar membrane damage, but relatively preserved capillary volume. Alterations of gas transport may be present even in subjects who had mild COVID-19 pneumonia and no or minimal persisting CT abnormalities. TRIAL REGISTRY: ClinicalTrials.gov PRS: No.: NCT04610554 Unique Protocol ID: SARS-CoV-2_DLNO 2020.
Keywords: COVID-19; alveolar membrane diffusive conductance; carbon monoxide; ground glass opacities; lung diffusing capacity; nitric oxide.
. 2021 Feb;9(4):e14748.
doi: 10.14814/phy2.14748.
Lung diffusing capacity for nitric oxide and carbon monoxide following mild-to-severe COVID-19
Giovanni Barisione[SUP] 1 [/SUP], Vito Brusasco[SUP] 2 [/SUP]
Affiliations
- PMID: 33625799
- DOI: 10.14814/phy2.14748
Abstract
A decreased lung diffusing capacity for carbon monoxide (DL[SUB]CO[/SUB] ) has been reported in a variable proportion of subjects over the first 3 months of recovery from severe coronavirus disease 2019 (COVID-19). In this study, we investigated whether measurement of lung diffusing capacity for nitric oxide (DL[SUB]NO[/SUB] ) offers additional insights on the presence and mechanisms of gas transport abnormalities. In 94 subjects, recovering from mild-to-severe COVID-19 pneumonia, we measured DL[SUB]NO[/SUB] and DL[SUB]CO[/SUB] between 10 and 266 days after each patient was tested negative for severe acute respiratory syndrome coronavirus 2. In 38 subjects, a chest computed tomography (CT) was available for semiquantitative analysis at six axial levels and automatic quantitative analysis of entire lungs. DL[SUB]NO[/SUB] was abnormal in 57% of subjects, independent of time of lung function testing and severity of COVID-19, whereas standard DL[SUB]CO[/SUB] was reduced in only 20% and mostly within the first 3 months. These differences were not associated with changes of simultaneous DL[SUB]NO[/SUB] /DL[SUB]CO[/SUB] ratio, while DL[SUB]CO[/SUB] /V[SUB]A[/SUB] and DL[SUB]NO[/SUB] /V[SUB]A[/SUB] were within normal range or slightly decreased. DL[SUB]CO[/SUB] but not DL[SUB]NO[/SUB] positively correlated with recovery time and DL[SUB]CO[/SUB] was within the normal range in about 90% of cases after 3 months, while DL[SUB]NO[/SUB] was reduced in more than half of subjects. Both DL[SUB]NO[/SUB] and DL[SUB]CO[/SUB] inversely correlated with persisting CT ground glass opacities and mean lung attenuation, but these were more frequently associated with DL[SUB]NO[/SUB] than DL[SUB]CO[/SUB] decrease. These data show that an impairment of DL[SUB]NO[/SUB] exceeding standard DL[SUB]CO[/SUB] may be present during the recovery from COVID-19, possibly due to loss of alveolar units with alveolar membrane damage, but relatively preserved capillary volume. Alterations of gas transport may be present even in subjects who had mild COVID-19 pneumonia and no or minimal persisting CT abnormalities. TRIAL REGISTRY: ClinicalTrials.gov PRS: No.: NCT04610554 Unique Protocol ID: SARS-CoV-2_DLNO 2020.
Keywords: COVID-19; alveolar membrane diffusive conductance; carbon monoxide; ground glass opacities; lung diffusing capacity; nitric oxide.