Correlation of D-dimer and Outcomes in COVID-19 Patients.

BACKGROUND: The coronavirus disease 2019 (COVID-19) global pandemic has impacted daily life and medical practices around the world. Hospitals are continually making observations about this unique population as it relates to laboratory data and outcomes. Plasma D-dimer levels have been shown to be promising as a prognostic factor for outcomes in COVID-19 patients. This single institution retrospective study investigates the correlation between D-dimer and patient outcomes in our inpatient COVID-19 patient population. METHODS: COVID-19 confirmed positive patients who were admitted between March 2020 and May 2020 at our hospital were identified. Admission and peak D-dimer values and patient outcomes, including intubation and mortality, were retrospectively analyzed. RESULTS: Ninety-seven patients met criteria for inclusion in the study Mean age was 63.2 years, median admission D-dimer 2.35ug/mL, and median peak D-dimer 2.74ug/mL. Average time to peak D-dimer was 3.2 days. Patient's requiring intubation had higher admission D-dimers (3.79ug/mL vs. 1.62 ug/mL). DISCUSSION: Higher admission and peak D-dimer values were associated with worsening clinical outcomes, specifically with higher rates of intubation and mortality. Noting D-dimer trends early in a patients' COVID course, regardless of patients' clinical condition, may allow opportunities for physicians to provide early intervention to prevent these outcomes.

MUlticenter STudy of tissue plasminogen activator (alteplase) use in COVID-19 severe respiratory failure (MUST COVID): A retrospective cohort study.

Background: Few therapies exist to treat severe COVID-19 respiratory failure once it develops. Given known diffuse pulmonary microthrombi on autopsy studies of COVID-19 patients, we hypothesized that tissue plasminogen activator (tPA) may improve pulmonary function in COVID-19 respiratory failure. Methods: A multicenter, retrospective, observational study of patients with confirmed COVID-19 and severe respiratory failure who received systemic tPA (alteplase) was performed. Seventy-nine adults from seven medical centers were included in the final analysis after institutional review boards' approval; 23 were excluded from analysis because tPA was administered for pulmonary macroembolism or deep venous thrombosis. The primary outcome was improvement in the PaO2/FiO2 ratio from baseline to 48 h after tPA. Linear mixed modeling was used for analysis. Results: tPA was associated with significant PaO2/FiO2 improvement at 48 h (estimated paired difference = 23.1 ± 6.7), which was sustained at 72 h (interaction term p < 0.00). tPA administration was also associated with improved National Early Warning Score 2 scores at 24, 48, and 72 h after receiving tPA (interaction term p = 0.00). D-dimer was significantly elevated immediately after tPA, consistent with lysis of formed clot. Patients with declining respiratory status preceding tPA administration had more marked improvement in PaO2/FiO2 ratios than those who had poor but stable (not declining) respiratory status. There was one intracranial hemorrhage, which occurred within 24 h following tPA administration. Conclusions: These data suggest tPA is associated with significant improvement in pulmonary function in severe COVID-19 respiratory failure, especially in patients whose pulmonary function is in decline, and has an acceptable safety profile in this patient population.

Wittmann Patch : Superior Closure for the Open Abdomen.

INTRODUCTION: Damage control laparotomy (DCL) is a life-saving surgical technique, but the resultant open abdomen (OA) carries serious morbidity/mortality. Many methods are utilized to manage OAs, but discrepancy exists in distinguishing closure from coverage techniques. We observed a difference in our DCL patient outcomes managed with the Wittmann Patch (WP) closure device versus the more popular ABThera (AB) coverage device. We hypothesized that the WP contributed to an improved fascial closure rate of the OAs after DCL. METHODS: A retrospective review of OAs managed with the AB or WP at our Level 1 trauma center was performed using billing codes to capture DCL patients from 2011 to 2019. Patients were divided into AB alone or WP groups. Major endpoints included primary fascial closure (PFC) and delayed fascial closure (DFC, fascial closure after greater than 7 days). RESULTS: 189 patients were identified as AB and 38 as WP. Rates of death before closure, age, gender, and Injury Severity Score were similar in both groups. PFC = 81%-90% for AB versus WP, respectively. Excluding patients with preexisting hernias PFC = 87%-100% for AB versus WP (P < .05) and DFC = 44%-100% for AB versus WP (P ≤ 0.001). WP had a statistically higher rate of PFC and DFC. There was a decreased incidence of complications in the WP versus AB group. CONCLUSIONS: While not well reported in the peer-reviewed literature, the application of the WP for management of the OA is an active form of pursuing PFC when compared with the AB, a coverage device. Our interinstitutional results have demonstrated superior PFC and DFC rates and fewer complications, in patients managed with the WP compared with the AB.

Does Human Amnion Membrane Prevent Postoperative Abdominal Adhesions?

BACKGROUND: Adhesions are bands of tissue that form postoperatively after intra-abdominal surgery. Adhesions cause significant morbidity and despite ongoing research no agent or method has been shown to completely prevent adhesions. Human amnion-derived matrix is a complex tissue matrix derived from human placenta and has been used in other areas of surgery to promote healing and decrease scar tissue formation. Our hypothesis was that aerosolized human amnion-derived matrix particulate solution (HAMPS) applied during abdominal surgery would decrease adhesion formation in rats. METHODS: Twenty-four Sprague-Dawley rats were divided into 4 different groups. Group 1 was the control group (CG) which had cecal abrasion 20× with a surgical rasp to generate the adhesion model. Groups 2-4 were the treatment groups (TGs) and had cecal abrasion plus application of the HAMPS at concentrations of 6.25, 12.5, and 25 mg/cc, respectively. After 30 days, rats were euthanized and adhesion assessment performed. RESULTS: In all groups there were minimal adhesions noted at necropsy. Moderate inflammation was 33% in CG versus 11% in combined TGs. Average adhesion was 1.00 in CG versus 0.44 in combined TGs. This indicated an observational improvement in adhesions/inflammation in the TGs, although this did not reach statistical significance. There was a trend toward significance in the 12.5 mg/cc group alone (P = .054). CONCLUSION: Overall, HAMPS showed an observational decrease in adhesions in TGs although not statistically significant. There was a trend toward significance in the 12.5 mg group. Additional studies will have to be performed to further evaluate this subgroup.

Early outcomes with utilization of tissue plasminogen activator in COVID-19-associated respiratory distress: A series of five cases.

BACKGROUND: Coronavirus patients demonstrate varying degrees of respiratory insufficiency; many will progress to respiratory failure with a severe version of acute respiratory distress syndrome refractory to traditional supportive strategies. Providers must consider alternative therapies to deter or prevent the cascade of decompensation to fulminant respiratory failure. METHODS: This is a case-series of five COVID-19 positive patients who demonstrated severe hypoxemia, declining respiratory performance, and escalating oxygen requirements. Patients met the following criteria: COVID-19 positivity, worsening respiratory performance, severe hypoxemia (PaO2 ≤ 80) despite traditional supportive measures, escalating supplemental oxygen requirements, and D-dimer greater than 1.5 µg/mL. All patients received protocol directed thrombolytic therapy with tissue plasminogen activator (tPA). RESULTS: All five patients improved without deleterious effects of thrombolytic therapy. Patient one was on maximum ventilator support, paralytics, and prone positioning without improvement. During tPA administration his PaO2/FIO2 ratio improved from 69 to 127. Ventilator support was weaned immediately on posttreatment day 1, and he was extubated on posttreatment day 12. Our second through fifth patients were not intubated at time of initiation of tPA therapy. These patients each required significant oxygen supplementation trending toward intubation. After tPA therapy, all patients demonstrated a noticeable increase in PaO2 values overtime. Three of these patients avoided intubation due to COVID-19-associated respiratory failure. CONCLUSION: Administration of thrombolytics was followed by overall improvement in patients' oxygen requirements, and in three cases, prevented progression to mechanical ventilation, without deleterious effects. Clinical trials of thrombolytic therapy would further serve to underscore the efficacy and utility of this therapy. LEVEL OF EVIDENCE: Case series of therapeutic effect, Level V.

Monte Carlo simulations of thin hydrocarbon films: composition heterogeneity and structure at the solid-liquid and liquid-vapor interfaces.

The structural properties of 10 nm thick lubricant films consisting of binary and ternary n-alkane mixtures (8 ≤ n ≤ 12) adsorbed on a structureless metal substrate were studied for several temperatures and compositions using Monte Carlo simulations. Configurational-bias Monte Carlo identity switch moves are essential to sample the spatial distribution in these mixtures. Longer alkanes are found to preferentially adsorb onto the substrate while shorter alkanes are enriched at the liquid-vapor interface. This preferential adsorption is evident even when the two chains differ by only one methylene unit and the longer chain is the minor component. Enhanced composition heterogeneity and orientational ordering and fewer gauche defects are characteristic features of the first layer near the substrate.