Personalized ventilatory strategy based on lung recruitablity in COVID-19-associated acute respiratory distress syndrome: a prospective clinical study.

BACKGROUND: Heterogeneity is an inherent nature of ARDS. Recruitment-to-inflation ratio has been developed to identify the patients who has lung recruitablity. This technique might be useful to identify the patients that match specific interventions, such as higher positive end-expiratory pressure (PEEP) or prone position or both. We aimed to evaluate the physiological effects of PEEP and body position on lung mechanics and regional lung inflation in COVID-19-associated ARDS and to propose the optimal ventilatory strategy based on recruitment-to-inflation ratio. METHODS: Patients with COVID-19-associated ARDS were consecutively enrolled. Lung recruitablity (recruitment-to-inflation ratio) and regional lung inflation (electrical impedance tomography [EIT]) were measured with a combination of body position (supine or prone) and PEEP (low 5 cmH2O or high 15 cmH2O). The utility of recruitment-to-inflation ratio to predict responses to PEEP were examined with EIT. RESULTS: Forty-three patients were included. Recruitment-to-inflation ratio was 0.68 (IQR 0.52-0.84), separating high recruiter versus low recruiter. Oxygenation was the same between two groups. In high recruiter, a combination of high PEEP with prone position achieved the highest oxygenation and less dependent silent spaces in EIT (vs. low PEEP in both positions) without increasing non-dependent silent spaces in EIT. In low recruiter, low PEEP in prone position resulted in better oxygenation (vs. both PEEPs in supine position), less dependent silent spaces (vs. low PEEP in supine position) and less non-dependent silent spaces (vs. high PEEP in both positions). Recruitment-to-inflation ratio was positively correlated with the improvement in oxygenation and respiratory system compliance, the decrease in dependent silent spaces, and was inversely correlated with the increase in non-dependent silent spaces, when applying high PEEP. CONCLUSIONS: Recruitment-to-inflation ratio may be useful to personalize PEEP in COVID-19-associated ARDS. Higher PEEP in prone position and lower PEEP in prone position decreased the amount of dependent silent spaces (suggesting lung collapse) without increasing the amount of non-dependent silent spaces (suggesting overinflation) in high recruiter and in low recruiter, respectively.

Ivermectin administration is associated with lower gastrointestinal complications and greater ventilator-free days in ventilated patients with COVID-19: A propensity score analysis.

INTRODUCTION: COVID-19 patients have been reported to have digestive symptoms with poor outcome. Ivermectin, an antiparasitic drug, has been used in COVID-19 patients. The objective of this study was to evaluate whether ivermectin has effects on gastrointestinal complications and ventilator-free days in ventilated patients with COVID-19. METHODS: COVID-19 patients who were mechanically ventilated in the ICU were included in this study. The ventilated patients who received ivermectin within 3 days after admission were assigned to the Ivermectin group, and the others were assigned to the Control group. Patients in the Ivermectin group received ivermectin 200 µg/kg via nasal tube. The incidence of gastrointestinal complications and ventilator-free days within 4 weeks from admission were evaluated as clinical outcomes using a propensity score with the inverse probability weighting method. RESULTS: We included 88 patients in this study, of whom 39 patients were classified into the Ivermectin group, and 49 patients were classified into the Control group. The hazard ratio for gastrointestinal complications in the Ivermectin group as compared with the Control group was 0.221 (95% confidence interval [CI], 0.057 to 0.855; p = 0.029) in a Cox proportional-hazard regression model. The odds ratio for ventilator-free days as compared with the Control group was 1.920 (95% CI, 1.076 to 3.425; p = 0.027) in a proportional odds logistic regression model. CONCLUSIONS: Ivermectin improved gastrointestinal complications and the number of ventilator-free days in severe COVID-19 patients undergoing mechanical ventilation. Prevention of gastrointestinal symptoms by SARS-Cov-2 might be associated with COVID-19 outcome.

Haloperidol Suppresses NF-kappaB to Inhibit Lipopolysaccharide-Induced Pro-Inflammatory Response in RAW 264 Cells.

BACKGROUND Haloperidol, a tranquilizing agent, is administered both to treat symptoms of psychotic disorders and to sedate agitated and delirious patients. Notably, haloperidol has been suggested to inhibit the immune response through unknown mechanisms. We hypothesized that the sedative modulates the immune response via NF-κB. MATERIAL AND METHODS Using flow cytometry, we analyzed the effects of haloperidol on expression CD80 and CD86 in RAW 264 cells and in primary macrophages derived from bone marrow. Secretion of interleukin (IL)-1ß, IL-6, and IL-12 p40 was measured by enzyme-linked immunosorbent assay. In addition, NF-κB activation was evaluated using a reporter assay based on secretory embryonic alkaline phosphatase. Finally, synthetic antagonists were used to identify the dopamine receptor that mediates the effects of haloperidol. RESULTS Haloperidol inhibited NF-κB activation, and thereby suppressed expression of CD80, as well as secretion of IL-1ß, IL-6, and IL-12 p40. CD80 and IL-6 levels were similarly attenuated by a D2-like receptor antagonist, but not by a D1-like receptor antagonist. CONCLUSIONS The data strongly suggest that haloperidol inhibits the immune response by suppressing NF-kB signaling via the dopamine D2 receptor.

Dysbiosis of gut microbiota in patients with severe COVID-19.

Aim: Altered gut microbiota has been proposed as one of the causes of exacerbation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2/COVID-19) from the perspective of the gut-lung axis. We aimed to evaluate gut microbiota in mechanically ventilated patients with COVID-19 prior to using antibiotics. Methods: We retrospectively selected for enrollment COVID-19 patients who required mechanical ventilation on admission but who had not used antibiotics before admission to observe the influence of SARS-Cov-2 on gut microbiota. Fecal samples were collected serially on admission and were evaluated by 16S rRNA gene deep sequencing. Results: The phylum of Bacteroidetes decreased, and those of Firmicutes and Actinobacteria increased in COVID-19 patients compared with those in healthy controls (p < 0.001). The main commensals of Bacteroides, Faecalibacterium, and Blautia at the genus level were significantly decreased in the COVID-19 patients, and opportunistic bacteria including Corynebacterium, Anaerococcus, Finegoldia Peptoniphilus, Actinomyces, and Enterococcus were increased (p < 0.001). α-Diversity and ß-diversity in COVID-19 patients significantly changed compared with those in the healthy controls. Conclusion: The commensal gut microbiota were altered, and opportunistic bacteria increased in patients with severe COVID-19 who required mechanical ventilation on admission.

Factors Associated With Prolonged Ventilation in Patients Receiving Prone Positioning Protocol With Muscle Relaxants for Severe COVID-19 Pneumonia.

BACKGROUND: Prone positioning and neuromuscular blocking agents (NMBAs) are frequently used to treat severe respiratory failure from COVID-19 pneumonia. Prone positioning has shown to improve mortality, whereas NMBAs are used to prevent ventilator asynchrony and reduce patient self-inflicted lung injury. However, despite the use of lung-protective strategies, high death rates in this patient population have been reported. METHODS: We retrospectively examined the factors affecting prolonged mechanical ventilation in subjects receiving prone positioning plus muscle relaxants. The medical records of 170 patients were reviewed. Subjects were divided into 2 groups according to ventilator-free days (VFDs) at day 28. Whereas subjects with VFDs < 18 d were defined as prolonged mechanical ventilation, subjects with VFDs ≥18 d were defined as short-term mechanical ventilation. Subjects' baseline status, status at ICU admission, therapy before ICU admission, and treatment in the ICU were studied. RESULTS: Under the proning protocol for COVID-19, the mortality rate in our facility was 11.2%. The prognosis may be improved by avoiding lung injury in the early stages of mechanical ventilation. According to multifactorial logistic regression analysis, persistent SARS-CoV-2 viral shedding in blood (P = .03), higher daily corticosteroid use before ICU admission (P = .007), delayed recovery of lymphocyte count (P < .001), and higher maximal fibrinogen degradation products (P = .039) were associated with prolonged mechanical ventilation. A significant relationship was found between daily corticosteroid use before admission and VFDs by squared regression analysis (y = -0.00008522x2 + 0.01338x + 12.8; x: daily corticosteroids dosage before admission [prednisolone mg/d]; y: VFDs/28 d, R2 = 0.047, P = .02). The peak point of the regression curve was 13.4 d at 78.5 mg/d of the equivalent prednisolone dose, which corresponded to the longest VFDs. CONCLUSIONS: Persistent SARS-CoV-2 viral shedding in blood, high corticosteroid dose from the onset of symptoms to ICU admission, slow recovery of lymphocyte counts, and high levels of fibrinogen degradation products after admission were associated with prolonged mechanical ventilation in subjects with severe COVID-19 pneumonia.

Fatal cytomegalovirus pneumonia in a critically ill patient with COVID-19.

Coronavirus disease 2019 (COVID-19) can cause severe lymphopenia and respiratory failure requiring prolonged invasive mechanical ventilation (MV). COVID-19 patients with severe lymphopenia or respiratory failure are at risk of developing secondary infections. Here, we present the needle autopsy findings of a critically ill patient with COVID-19 who required reintubation and prolonged MV, and eventually died of secondary cytomegalovirus (CMV) pneumonia. This case highlights the potential risk of long-term steroid use and the need for routine monitoring for CMV infection in critically ill patients with COVID-19.

Attaining Low Tidal Volume Ventilation During Patient Triggered Ventilation in Sedated Subjects.

BACKGROUND: Low tidal volume (VT) ventilation has become the preferred approach in patients in the ICU. Sedation reduces VT by attenuating respiratory drive. Even in deep sedation, some patients exhibit high VT. We aimed to determine factors associated with low VT ventilation in deeply sedated subjects who exhibited an inspiratory effort by examination of the acid/base balance using the Stewart model. METHODS: The medical records of 630 consecutive subjects admitted to the ICU over 1 y were reviewed retrospectively, and daily data sets of patients with a persistent inspiratory effort, PaO2 /FIO2 < 300 mm Hg, PEEP > 5 cm H2O, and a Richmond Agitation Sedation Scale score of -4 or -5 who received assisted pressure-regulated ventilation were collected. The data sets were stratified into high VT (≥ 8 mL/kg predicted body weight [PBW]) and low VT (> 8 mL/kg PBW) groups. RESULTS: Among 235 matched data sets from 100 subjects, 101 and 134 data sets were in the low VT and high VT groups, respectively. Set pressure was not different between the groups. PEEP was lower in the low VT group, and opioids were more frequently used in the high VT group. Strong ion difference (SID) was higher in the low VT group. Multivariate analysis revealed that higher SID, lower total nonvolatile weak anion (ATOT), and absence of opioid administration were associated with attaining low VT ventilation. Furthermore, VT/PBW and SID demonstrated a weak inverse correlation, whereas VT/PBW and ATOT exhibited a weak correlation. VT/PBW was lower in the group with higher SID and lower ATOT, indicating a tendency of metabolic alkalosis. CONCLUSIONS: Despite weak effects of high SID and low ATOT, efficient management of the buffering function might be a feasible strategy to achieve low VT ventilation.

Midazolam suppresses the lipopolysaccharide-stimulated immune responses of human macrophages via translocator protein signaling.

BACKGROUND: Benzodiazepines are widely used for anesthesia and sedation and have immunomodulatory properties that may negatively influence clinical outcomes; however, the cellular targets and intermediary signaling pathways involved are unclear. We examined the immunomodulatory effects of the benzodiazepine midazolam on human macrophages and associated molecular mechanisms. METHODS: We analyzed effects of midazolam pretreatment on lipopolysaccharide (LPS)-induced upregulation of the costimulatory molecule CD80 and secretion of the pro-inflammatory factors interleukin-6 (IL-6), tumor necrosis factor-α, interleukin-10, and nitric oxide (NO) in the human monocyte-macrophage cell line THP-1 and in peripheral monocyte-derived macrophages (PMDMs). The effects of midazolam on NF-κB, IκBα protein, and mitogen-activated protein kinase (MAPK) activation were analyzed in THP-1 cells. We analyzed the involvement of translocator protein (TSPO) in the immunomodulatory effects of midazolam using TSPO ligands. The role of TSPO was investigated using THP-1 cells overexpressing TSPO and THP-1 cells with TSPO knockdown through transfection with small interfering RNA for TSPO. RESULTS: Midazolam suppressed LPS-induced upregulation of CD80 and release of IL-6 and NO in THP-1 cells and PMDMs. Additionally, midazolam suppressed the activation of NF-κB/AP-1 and MAPKs in human THP-1 cells. The assessed synthetic TSPO ligands showed the same inhibitory effects on macrophage activation as midazolam. Macrophages overexpressing TSPO exhibited enhanced susceptibility to immunosuppression by midazolam, and macrophages lacking TSPO expression exhibited reduced effects of midazolam. CONCLUSION: Midazolam inhibits LPS-stimulated immune responses in human macrophages by activating TSPO signaling. Suppression of macrophage activity may contribute to deleterious side effects of benzodiazepines reported in critically ill patients.

Transversus abdominis plane block for bilateral orchiopexy in an 8-year-old patient with Eisenmenger's syndrome.

Non-cardiac surgery should only be performed in patients with Eisenmenger's syndrome if absolutely mandatory because these patients are at high risk of perioperative mortality. Proper anesthetic and perioperative pain management in these patients remains a controversial topic. Transversus abdominis plane (TAP) block provides safe and beneficial perioperative analgesia in adults and children; however, no report has described the performance of TAP block in a child with Eisenmenger's syndrome. Herein, we describe the performance of bilateral orchiopexy for cryptorchidism in an 8-year-old boy with Eisenmenger's syndrome due to an uncorrected muscular ventricular septal defect (mVSD). Anesthesia induction and maintenance were uneventful. Subsequently, the patient received ultrasound-guided bilateral TAP block by using 10 mL of 0.25 % levobupivacaine shortly before recovery from anesthesia. The TAP block provided pain relief and maintenance of stable hemodynamics during the postoperative period. We successfully used a TAP block in a child with Eisenmenger's syndrome to provide postoperative analgesia. No side effects were apparent during the perioperative period. TAP block can be considered a beneficial pain management technique for analgesia in children with Eisenmenger's syndrome.