Detection of residual pulmonary alterations with lung ultrasound and effects on postoperative pulmonary complications for patients with asymptomatic SARS-CoV-2 infection undergoing surgeries.

Background: For patients with a clinical course of active SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection, there may be a higher risk of perioperative complications. Our main objective is to detect the residual pulmonary alterations in asymptomatic patients after SARS-CoV-2 infection undergoing surgery and determine their relationship with the clinical course of SARS-CoV-2 infection. The secondary aim is to investigate whether the presence of residual pulmonary alterations have any affects on the severity of postoperative pulmonary complications.

Methods: After approval by the Hospital's Ethical Committee, this prospective observational study included consecutive patients (n=103) undergoing various surgical procedures and anesthetic techniques with a history of past SARS-CoV-2 infection. On the day of surgery these patients remained asymptomatic and the polymerase chain reaction (PCR) test for SARS-CoV-2 was negative. The history, physical findings, and clinical course of SARS-CoV-2 infection were recorded. Lung ultrasound was performed before surgery to evaluate the possible residual pulmonary alterations (≥ 3 B-lines and pleural thickening), along with determitation of pulmonary static compliance values during surgery. Postoperative pulmonary complications were collected during hospital stay.

Results: 24.27% (n=25) patients presented ≥ 3 B-lines, and 28% (n=29) patients presented pleural thickening. For 15 patients (21.7%) the pulmonary compliance was < 40 mL/cm HO. Patients with pleural thickening had a higher incidence of pneumonia, acute respiratory syndrome distress, a need for vasoactive drugs and required more days of hospitalization during SARS-CoV-2 infection (p= 0.004, 0.001, 0.03, 0.00 respectively). Patients with ≥ 3 B-lines needed more days in an intensive care unit and vasoactive drugs during SARS-CoV2 infection (p= 0.04, 0.004 respectively). Postoperative pulmonary complications were observed in 5.8% (n=6) of the patients, and were more frequent in the presence of both, ≥ 3 B-lines and pleural thickening (p= 0.01).

Conclusions: In asymptomatic post-COVID-19 patients, pathological findings detected by lung ultrasound before surgery are associated with the severity of the SARS-CoV2 infection and resulted in more postoperative pulmonary complications. In these patients, the incidence of postoperative pulmonary complications appears similar to that described in the surgical population before the pandemic.

Trial Registration: clinicaltrials.gov (NCT04922931). June 21, 2021. "Retrospectively registered".