Repercussions of SARS-CoV-2 infection on intrapulmonary shunt in patients undergoing one-lung ventilation.

Background: Hypoxic pulmonary vasoconstriction is the most important regulatory mechanism by which right-to-left shunts decrease during one-lung ventilation (OLV), but the effects of pulmonary microarterial thrombosis and impaired HPV after SARS-CoV-2 infection on intrapulmonary shunt during OLV remain unknown. The aim of this study was to observe the changes of intrapulmonary shunt in patients undergoing thoracoscopic partial pneumonectomy at different periods after SARS-CoV-2 infection compared with patients without SARS-CoV-2 infection history.

Methods: A total of 80 patients who underwent elective thoracoscopic partial lung resection and were classified as American Society of Anaesthesiologists (ASA) grades I-II were selected and divided into 4 groups (n = 20 in each group): patients not infected with SARS-CoV-2 (Group A), patients infected with SARS-CoV-2 for 5-8 weeks (Group B), patients infected with SARS-CoV-2 for 9-12 weeks (Group C), and patients infected with SARS-CoV-2 for 13-16 weeks (Group D). For all patients, the same anaesthesia method was adopted, and anaesthesia was maintained with propofol, remifentanil, and cisatracurium. Radial artery and mixed venous blood gases were measured at 10 min of two-lung ventilation (TLV), 15 min of one-lung ventilation (OLV15), and 30 min of OLV (OLV30) in the lateral recumbent position to calculate the intrapulmonary shunt. Multiple linear regression analysis was employed to investigate the association between intrapulmonary shunt and SARS-CoV-2 infection.

Results: Qs/Qt at TLV was significantly higher in Groups B and C than in Group A (P < 0.05), and PaO at TLV was significantly lower in Groups B and C than in Group A (P < 0.05). Qs/Qt values at OLV15 and OLV30 were significantly higher in Group B, C or D than in Group A (P < 0.05), and PaO values at OLV15 and OLV30 were significantly lower in Groups B, C or D than in Group A (P < 0.05). Multiple linear regression analysis revealed that SARS-CoV-2 infection (95%CI -4.245 to -0.679, P = 0.007) was an independent risk factor for increased intrapulmonary shunt during TLV, while SARS-CoV-2 infection (95%CI 0.124 to 3.661, P = 0.036), exacerbation of COVID-19 clinical classification (95%CI -5.203 to -1.139, P = 0.003), and persistent symptoms (95%CI -12.122 to -5.522, P < 0.001) were independent risk factors for increased intrapulmonary shunt during OLV after SARS-CoV-2 infection.

Conclusion: SARS-CoV-2 infection increased intrapulmonary shunt and reduced oxygenation. Although oxygenation improved at TLV after 13-16 weeks of infection, intrapulmonary shunt and oxygenation under OLV took longer to recover.

Trial Registration: Chinese Clinical Trial Registry, Retrospectively registered, Full date of first registration: 17/05/2023, Registration number: ChiCTR2300071539.