PPV May Be a Starting Point to Achieve Circulatory Protective Mechanical Ventilation

Pulse pressure variation (PPV) is a mandatory index for hemodynamic monitoring during mechanical ventilation. The changes in pleural pressure (Ppl) and transpulmonary pressure (PL) caused by mechanical ventilation are the basis for PPV and lead to the effect of blood flow. If the state of hypovolemia exists, the effect of the increased Ppl during mechanical ventilation on the right ventricular preload will mainly affect the cardiac output, resulting in a positive PPV. However, PL is more influenced by the change in alveolar pressure, which produces an increase in right heart overload, resulting in high PPV. In particular, if spontaneous breathing is strong, the transvascular pressure will be extremely high, which may lead to the promotion of alveolar flooding and increased RV flow. Asynchronous breathing and mediastinal swing may damage the pulmonary circulation and right heart function. Therefore, according to the principle of PPV, a high PPV can be incorporated into the whole respiratory treatment process to monitor the mechanical ventilation cycle damage/protection regardless of the controlled ventilation or spontaneous breathing. Through the monitoring of PPV, the circulation-protective ventilation can be guided at bedside in real time by PPV.

297 The Effects of Chromium Propionate Supplementation to Yearling Steers in a Commercial Feedyard on Growth Performance, Carcass Characteristics and Health

British crossbred steers [n = 3074; initial body weight (BW) = 358 ± 37 kg] were used to evaluate the effects of chromium propionate supplementation to yearling steers in a commercial feedyard on growth performance, carcass characteristics and health. Steers were blocked by initial BW; pens were assigned randomly to one of two dietary treatments within block. Treatments, replicated in 15 pens/treatment with 75 to 135 head per pen, included: 1) control, 0 mg supplemental Cr/kg dietary dry matter (DM) (CTL); 2) 0.50 mg supplemental Cr/kg diet DM (chromium propionate; KemTRACE® Chromium 0.04%, Kemin Industries, Des Moines, IA) (CR). Final BW (638 vs. 641 kg.), average daily gain, (1.81 vs. 1.82 kg), DM intake (11.02 vs. 11.02 kg) and gain efficiency (0.164 vs 0.165) did not differ between CTL and CR, respectively (P ≥ 0.75). No differences among treatments for hot carcass weight (407 vs. 408 kg., CTL and CR, respectively), dressing percentage, longissimus muscle area, or yield grade were observed (P ≥ 0.15). Twelfth-rib fat thickness tended (P = 0.10) to be greater for CR vs. CTL (1.55 vs 1.29 cm, respectively). A trend (P = 0.10) for marbling score to be higher for CR vs. CTL was detected (452 vs. 440, respectively). Distribution of quality grade was similar between CR and CTL; 1.52% of carcasses graded prime (P =0.68), and 87.2% of carcasses graded choice (P = 0.68). Respiratory morbidity was low (1.93%) and not different among treatments (P = 0.20); likewise, there was no difference in respiratory treatment rates between treatments (P ≥ 0.18). Supplementing Cr to high-performing yearling steers did not alter growth performance, carcass characteristics or health outcomes.

Daily monitoring of viral load measured as SARS-CoV-2 antigen and RNA in blood, IL-6, CRP and complement C3d predicts outcome in patients hospitalized with COVID-19

Objectives We hypothesized that the amount of antigen produced in the body during a COVID-19 infection might differ between patients, and that maximum concentrations would predict the degree of both inflammation and outcome for patients. Methods Eighty-four hospitalized and SARS-CoV-2 PCR swab-positive patients, were followed with blood sampling every day until discharge or death. A total of 444 serial EDTA plasma samples were analyzed for a range of biomarkers: SARS-CoV-2 nuclear antigen and RNA concentration, complement activation as well as several inflammatory markers, and KL-6 as a lung marker. The patients were divided into outcome groups depending on need of respiratory support and death/survival. Results Circulating SARS-CoV-2 nuclear antigen levels were above the detection limit in blood in 65 out of 84 COVID-19 PCR swab-positive patients on day one of hospitalization, as was viral RNA in plasma in 30 out of 84. In all patients, complete antigen clearance was observed within 24 days. There were definite statistically significant differences between the groups depending on their biomarkers, showing that the concentrations of virus RNA and antigen were correlated to the inflammatory biomarker levels, respiratory treatment and death. Conclusions Viral antigen is cleared in parallel with the virus RNA levels. The levels of antigens and SARS-CoV-2 RNA in the blood correlates with the level of IL-6, inflammation, respiratory failure and death. We propose that the antigens levels together with RNA in blood can be used to predict the severity of disease, outcome, and the clearance of the virus from the body.

Therapeutic options for Corona Virus Disease 2019 (COVID-19)

The aim of this review article is to put forth the therapeutic options for coronavirus disease 2019 (COVID-19). There is no specific treatment or therapy recommended for COVID-19 up to now. The therapeutic approaches should be ordered according to the severity of disease. These options can be listed from one to ten such as isolation; oxygen support; respiratory treatment; anticoagulant treatment; anti-inflammatory drugs; hydroxychloroquine and combinations therapies; antiviral drugs; convalescent plasma therapy; mesenchymal stem cells therapy and vaccination. According to the severity and stage of the disease, suitable options are recommended.

Potential Sedative and Therapeutic Value of Dexmedetomidine in Critical COVID-19 patients

The coronavirus 2019 disease (COVID-19) is an ongoing outbreak of respiratory disease, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The virus can invade various tissues and organs, causing multiple organ dysfunctions. Critically ill COVID-19 patients may develop acute respiratory distress syndrome and pneumonia, which are the major causes of hypoxemic respiratory failure and death due to SARS-CoV-2 infection. Thus, ventilation support (invasive or noninvasive), has become a common practice in respiratory treatment of COVID-19 patients. Patients receiving mechanical ventilation usually require sedation to alleviate anxiety, pain and discomfort. On the other hand, current clinical reports have indicated that a significant number of COVID-19 patients require prolonged intensive care unit (ICU) care and ventilation, which increases the risk of delirium. Thus, selection of appropriate sedative medications during this period is of utmost importance. Dexmedetomidine (DEX) is a sedative, anxiolytic and analgesic agent that acts through the α2-adrenoceptor. Its sedative property is notable due to the lack of respiratory depression. In addition, its cytoprotective, immunoregulatory and anti-inflammatory properties have been well established in preclinical settings. Based on these features, a number of recent studies have proposed DEX as a beneficial sedative agent that simultaneously mitigates the excessive inflammation and protects vital body organs in patients with severe COVID-19. In current brief review, we aimed to discuss the therapeutic benefits of DEX in managing different indications of COVID-19.

ANTIVIRAL PROPERTIES OF MICROALGAE AND CYANOBACTERIA

The recent outbreak of Corona Virus Disease (COVID-19) and the surge in accelerating the development of a vaccine to fight against the SARS-CoV-2 virus has imposed greater challenges to humanity worldwide. There is lack of research into the production of effective vaccines and methods of treatment against viral infections. As of now, strategies encompassing antiviral drugs and corticosteroids alongside mechanical respiratory treatment are in practice as frontline treatments. Though studies have reported that microalgae possess antiviral properties, only a few cases have presented the existence of antiviral compounds such as algal polysaccharides, lectins, aggluttinins, scytovirin, algal lipids such as sulfoquinovosyldiacylglycerol (SQDG), monogalactosyldiacylglycerides (MGDG) and digalactosyldiacylglycerides (DGDG), and algal biopigments especially chlorophyll analogues, marennine, phycobiliproteins, phycocyanin, phycoerythrin and allophycocyanin that are derived from marine and freshwater microalgae. Given the chemodiversity of bioactive compounds from microalgae and the present scenario, algal biotechnology is seen as a prospective source of antiviral and anti-inflammatory compounds that can be used to develop antiviral agents. Microalgae with potential as antivirals and microalgae derived functional compounds to treat viral diseases are summarized and can be used as a reference in developing algae-derived antivirals to treat SARS-CoV-2 and other similar viruses.

47 Effect of Zelnate administered at initial processing in high-risk, newly received beef calves on performance and morbidity

The objective of this study was to investigate the effects of Zelnate, a DNA immunostimulant, administered to calves (n = 261; BW 253 ± 4.0 kg) upon arrival, on morbidity and mortality, growth performance, and producer costs. Crossbred male beef calves (steers and bulls) were acquired from multiple auction markets and transported to the University of Arkansas stocker unit for a 42-d backgrounding period. Calves were randomly allocated to chute side into treatment groups: 1) Control (CON) in which no immunostimulant was administered or 2) Zelnate (ZEL), DNA immunostimulant administered. Animals were checked daily for signs of morbidity and treated with preplanned antibiotics. Records for morbidity and mortality were kept in addition to body temperature, clinical score, and body weight at the time of treatment. Data were analyzed using the GLIMMIX procedures of SAS. Significance was declared at P < 0.05 and tendencies were observed between 0.05 ≤ P < 0.10. No animals died during the duration of this study; however, Zelnate treated calves tended (P = 0.09) to have a lower relapse rate compared to control calves. Average daily gain was similar (P = 0.60) between the two treatment groups. This study also indicated that the treatment cost (Zelnate plus antibiotics) for the Zelnate group was more expensive than the cost to treat the control group (P < 0.01). Overall, our findings indicate that Zelnate administered upon arrival to high risk calves did not improve morbidity rates and respiratory treatment or affect performance; however, it did increase costs by $9.24 per calf. Based upon these results, Zelnate does not appear to be an effective therapy for BRD when given upon arrival.