Long-term antibody titers variation in unvaccinated patients receiving convalescent plasma or placebo for severe SARS-CoV-2 pulmonary infection.

BACKGROUND: Convalescent plasma (CP) became a prominent treatment in the early stages of the SARS-CoV-2 pandemic. In Argentina, a randomized clinical trial was executed to compare the use of CP in inpatients with severe COVID-19 pneumonia versus placebo. No differences in clinical outcomes or overall mortality between groups were observed. We conducted a cohort study in outpatients enrolled in the trial to describe long-term antibody titer variations between CP and placebo recipients. METHODS: Patients' total SARS-CoV-2 IgG antibodies against spike protein were collected 3, 6 and 12 months after hospital discharge from August 2020 to December 2021. In addition, reinfections, deaths and vaccination status were retrieved. Statistical analysis was performed using antibody geometric mean titers (GMT). All estimations were made considering the date of the trial infusion (placebo or CP) as time 0. RESULTS: From the 93 patients included in the follow-up, 64 had received CP and 29 placebo. We excluded all 12-month measurements because they were collected after the patients' vaccination date. At 90 days post-infusion, patients had an antibody GMT of 8.1 (IQR 7.4-8.1) in the CP group and 8.8 (IQR 8.1-9.1) in the placebo group. At 180 days, both groups had a GMT of 8.1 (IQR 7.4-8.1). No statistical differences in GMT were found between CP and placebo groups at 90 days (p = 0.12) and 180 days (p = 0.25). No patients registered a new COVID-19 infection; one died in the CP group from an ischemic stroke. CONCLUSIONS: No differences were observed in long-term antibody titers in unvaccinated patients that received CP or placebo after severe COVID-19 pneumonia.

The role of direct peritoneal resuscitation in the treatment of hemorrhagic shock after trauma and in emergency acute care surgery: a systematic review.

PURPOSE: Direct peritoneal resuscitation (DPR) has been used to help preserve microcirculation by reversing vasoconstriction and hypoperfusion associated with the pathophysiological process of shock, which can occur despite appropriate intravenous resuscitation. This approach depends on infusing a hyperosmolar solution intraperitoneally via a percutaneous catheter with the tip ending near the pelvis or the root of the mesentery. The abdomen is usually left open with a negative pressure abdominal dressing to continuously evacuate the infused dialysate. Hypertonicity of the solution triggers visceral vasodilation to help maintain blood flow, even during shock, and is also associated with reduced local inflammatory cytokines and other mediators, preservation of endothelial cell function, and mitigation of organ edema and necrosis. It also has a direct effect on liver perfusion and edema, more rapidly corrects electrolyte abnormalities compared to intravenous resuscitation alone, and may requireless intravenous fluid to stabilize blood pressure, all of which shortens the time required to close patients' abdomen. METHODS: An online query using the search term "direct peritoneal resuscitation" was carried out in PubMed, MEDLINE and SciELO, limited to publications indexed from January 2014 to June 2020. Of the 20 articles returned, full text was able to be obtained for 19. A manual review of included articles' references was resulted in the addition of 1 article, for a total of 20 included articles. RESULTS: The 20 articles were comprised of 15 animal studies, 4 clinical studies,and 1 expert opinion. The benefits include both local and possibly systemic effects on perfusion, hypoxia, acidosis, and inflammation, and are associated with improved outcomes and reduced complications. CONCLUSION: DPR shows promise in patients with hemorrhagic shock, septic shock, and other conditions resulting in an open abdomen after damage control laparotomy.