Effect of EIT-guided PEEP titration on prognosis of patients with moderate to severe ARDS: study protocol for a multicenter randomized controlled trial.

BACKGROUND: Acute respiratory syndrome distress (ARDS) is a clinical common syndrome with high mortality. Electrical impedance tomography (EIT)-guided positive end-expiratory pressure (PEEP) titration can achieve the compromise between lung overdistension and collapse which may minimize ventilator-induced lung injury in these patients. However, the effect of EIT-guided PEEP titration on the clinical outcomes remains unknown. The objective of this trial is to investigate the effects of EIT-guided PEEP titration on the clinical outcomes for moderate or severe ARDS, compared to the low fraction of inspired oxygen (FiO2)-PEEP table. METHODS: This is a prospective, multicenter, single-blind, parallel-group, adaptive designed, randomized controlled trial (RCT) with intention-to-treat analysis. Adult patients with moderate to severe ARDS less than 72 h after diagnosis will be included in this study. Participants in the intervention group will receive PEEP titrated by EIT with a stepwise decrease PEEP trial, whereas participants in the control group will select PEEP based on the low FiO2-PEEP table. Other ventilator parameters will be set according to the ARDSNet strategy. Participants will be followed up until 28 days after enrollment. Three hundred seventy-six participants will be recruited based on a 15% decrease of 28-day mortality in the intervention group, with an interim analysis for sample size re-estimation and futility assessment being undertaken once 188 participants have been recruited. The primary outcome is 28-day mortality. The secondary outcomes include ventilator-free days and shock-free days at day 28, length of ICU and hospital stay, the rate of successful weaning, proportion requiring rescue therapies, compilations, respiratory variables, and Sequential Organ Failure Assessment (SOFA). DISCUSSION: As a heterogeneous syndrome, ARDS has different responses to treatment and further results in different clinical outcomes. PEEP selection will depend on the properties of patients and can be individually achieved by EIT. This study will be the largest randomized trial to investigate thoroughly the effect of individual PEEP titrated by EIT in moderate to severe ARDS patients to date. TRIAL REGISTRATION: ClinicalTrial.gov NCT05207202. First published on January 26, 2022.

Optimal positive end-expiratory pressure reduces right ventricular dysfunction in COVID-19 patients on venovenous extracorporeal membrane oxygenation: A retrospective single-center study.

While mechanical ventilation practices on venovenous extracorporeal membrane oxygenation (VV ECMO) are variable, most institutions utilize a lung rest strategy utilizing relatively low positive end-expiratory pressure (PEEP). The effect of PEEP titration using esophageal manometry during VV ECMO on pulmonary and cardiac function is unknown. This was a retrospective study of 69 patients initiated on VV ECMO between March 2020 through November 2021. Patients underwent standard PEEP (typically 10 cm H2O) or optimal PEEP (PEEP titrated to an end-expiratory transpulmonary pressure 0-3 cm H2O) throughout the ECMO run. The optimal PEEP strategy had higher levels of applied PEEP (17.9 vs. 10.8 cm H2O on day 2 of ECMO), decreased incidence of hemodynamically significant RV dysfunction (4.55% vs. 44.0%, p = 0.0001), and higher survival to decannulation (72.7% vs. 44.0%, p = 0.022). Survival to discharge did not reach statistical significance (61.4% vs. 44.0%, p = 0.211). In univariate logistic regression analysis, optimal PEEP was associated with less hemodynamically significant RV dysfunction with an odds ratio (OR) of 0.06 (95% confidence interval [CI] = 0.01-0.27, p = 0.0008) and increased survival to decannulation with an OR of 3.39 (95% CI 1.23-9.79), p = 0.02), though other confounding factors may have contributed.

Noninvasive ventilation and high-flow nasal cannula in patients with acute hypoxemic respiratory failure by covid-19: A retrospective study of the feasibility, safety and outcomes.

BACKGROUND: Noninvasive ventilation (NIV) and High-flow nasal cannula (HFNC) are the main forms of treatment for acute respiratory failure. This study aimed to evaluate the effect, safety, and applicability of the NIV and HFNC in patients with acute hypoxemic respiratory failure (AHRF) caused by COVID-19. METHODS: In this retrospective study, we monitored the effect of NIV and HFNC on the SpO2 and respiratory rate before, during, and after treatment, length of stay, rates of endotracheal intubation, and mortality in patients with AHRF caused by COVID-19. Additionally, data regarding RT-PCR from physiotherapists who were directly involved in assisting COVID-19 patients and non-COVID-19. RESULTS: 62.2 % of patients were treated with HFNC. ROX index increased during and after NIV and HFNC treatment (P < 0.05). SpO2 increased during NIV treatment (P < 0.05), but was not maintained after treatment (P = 0.17). In addition, there was no difference in the respiratory rate during or after the NIV (P = 0.95) or HFNC (P = 0.60) treatment. The mortality rate was 35.7 % for NIV vs 21.4 % for HFNC (P = 0.45), while the total endotracheal intubation rate was 57.1 % for NIV vs 69.6 % for HFNC (P = 0.49). Two adverse events occurred during treatment with NIV and eight occurred during treatment with HFNC. There was no difference in the physiotherapists who tested positive for SARS-COV-2 directly involved in assisting COVID-19 patients and non-COVID-19 ones (P = 0.81). CONCLUSION: The application of NIV and HFNC in the critical care unit is feasible and associated with favorable outcomes. In addition, there was no increase in the infection of physiotherapists with SARS-CoV-2.

Respiratory function monitoring to improve the outcomes following neonatal resuscitation: a systematic review and meta-analysis.

IMPORTANCE: Animal and observational human studies report that delivery of excessive tidal volume (VT) at birth is associated with lung and brain injury. Using a respiratory function monitor (RFM) to guide VT delivery might reduce injury and improve outcomes. OBJECTIVE: To determine whether use of an RFM in addition to clinical assessment versus clinical assessment alone during mask ventilation in the delivery room reduces in-hospital mortality and morbidity of infants <37 weeks' gestation. STUDY SELECTION: Randomised controlled trials (RCTs) comparing RFM in addition to clinical assessment versus clinical assessment alone during mask ventilation in the delivery room of infants born <37 weeks' gestation. DATA ANALYSIS: Risk of bias was assessed using Covidence Collaboration tool and pooled into a meta-analysis using a random-effects model. The primary outcome was death prior to discharge. MAIN OUTCOME: Death before hospital discharge. RESULTS: Three RCTs enrolling 443 infants were combined in a meta-analysis. The pooled analysis showed no difference in rates of death before discharge with an RFM versus no RFM, relative risk (RR) 95% (CI) 0.98 (0.64 to 1.48). The pooled analysis suggested a significant reduction for brain injury (a combination of intraventricular haemorrhage and periventricular leucomalacia) (RR 0.65 (0.48 to 0.89), p=0.006) and for intraventricular haemorrhage (RR 0.69 (0.50 to 0.96), p=0.03) in infants receiving positive pressure ventilation with an RFM versus no RFM. CONCLUSION: In infants <37 weeks, an RFM in addition to clinical assessment compared with clinical assessment during mask ventilation resulted in similar in-hospital mortality, significant reduction for any brain injury and intraventricular haemorrhage. Further trials are required to determine whether RFMs should be routinely available for neonatal resuscitation.

Electrical impedance tomography: A compass for the safe route to optimal PEEP.

Setting the proper level of positive end-expiratory pressure (PEEP) is a cornerstone of lung protective ventilation. PEEP keeps the alveoli open at the end of expiration, thus reducing atelectrauma and shunt. However, excessive PEEP may contribute to alveolar overdistension. Electrical impedance tomography (EIT) is a non-invasive bedside tool that monitors in real-time ventilation distribution. Aim of this narrative review is summarizing the techniques for EIT-guided PEEP titration, while providing useful insights to enhance comprehension on advantages and limits of EIT for current and future users. EIT detects thoracic impedance to alternating electrical currents between pairs of electrodes and, through the analysis of its temporal and spatial variation, reconstructs a two-dimensional slice image of the lung depicting regional variation of ventilation and perfusion. Several EIT-based methods have been proposed for PEEP titration. The first described technique estimates the variations of regional lung compliance during a decremental PEEP trial, after lung recruitment. The optimal PEEP value is represented by the best compromise between lung collapse and overdistension. Later on, a second technique assessing alveolar recruitment by variation of the end-expiratory lung impedance was validated. Finally, the global inhomogeneity index and the regional ventilation delay, two EIT-derived parameters, showed promising results selecting the optimal PEEP value as the one that presents the lowest global inhomogeneity index or the lowest regional ventilation delay. In conclusion EIT represents a promising technique to individualize PEEP in mechanically ventilated patients. Whether EIT is the best technique for this purpose and the overall influence of personalizing PEEP on clinical outcome remains to be determined.

Noninvasive respiratory support and patient self-inflicted lung injury in COVID-19: a narrative review.

COVID-19 pneumonia is associated with hypoxaemic respiratory failure, ranging from mild to severe. Because of the worldwide shortage of ICU beds, a relatively high number of patients with respiratory failure are receiving prolonged noninvasive respiratory support, even when their clinical status would have required invasive mechanical ventilation. There are few experimental and clinical data reporting that vigorous breathing effort during spontaneous ventilation can worsen lung injury and cause a phenomenon that has been termed patient self-inflicted lung injury (P-SILI). The aim of this narrative review is to provide an overview of P-SILI pathophysiology and the role of noninvasive respiratory support in COVID-19 pneumonia. Respiratory mechanics, vascular compromise, viscoelastic properties, lung inhomogeneity, work of breathing, and oesophageal pressure swings are discussed. The concept of P-SILI has been widely investigated in recent years, but controversies persist regarding its mechanisms. To minimise the risk of P-SILI, intensivists should better understand its underlying pathophysiology to optimise the type of noninvasive respiratory support provided to patients with COVID-19 pneumonia, and decide on the optimal timing of intubation for these patients.

Acute kidney injury (AKI) in patients with Covid-19 infection is associated with ventilatory management with elevated positive end-expiratory pressure (PEEP).

BACKGROUND: Acute kidney injury (AKI) in Covid-19 patients admitted to the intensive care unit (ICU) is common, and its severity may be associated with unfavorable outcomes. Severe Covid-19 fulfills the diagnostic criteria for acute respiratory distress syndrome (ARDS); however, it is unclear whether there is any relationship between ventilatory management and AKI development in Covid-19 ICU patients. PURPOSE: To describe the clinical course and outcomes of Covid-19 ICU patients, focusing on ventilatory management and factors associated with AKI development. METHODS: Single-center, retrospective observational study, which assessed AKI incidence in Covid-19 ICU patients divided by positive end expiratory pressure (PEEP) tertiles, with median levels of 9.6 (low), 12.0 (medium), and 14.7 cmH2O (high-PEEP). RESULTS: Overall mortality was 51.5%. AKI (KDIGO stage 2 or 3) occurred in 38% of 101 patients. Among the AKI patients, 19 (53%) required continuous renal replacement therapy (CRRT). In AKI patients, mortality was significantly higher versus non-AKI (81% vs. 33%, p < 0.0001). The incidence of AKI in low-, medium-, or high-PEEP patients were 16%, 38%, and 59%, respectively (p = 0.002). In a multivariate analysis, high-PEEP patients showed a higher risk of developing AKI than low-PEEP patients (OR = 4.96 [1.1-21.9] 95% CI p < 0.05). ICU mortality rate was higher in high-PEEP patients, compared to medium-PEEP or low-PEEP patients (69% vs. 44% and 42%, respectively; p = 0.057). CONCLUSION: The use of high PEEP in Covid-19 ICU patients is associated with a fivefold higher risk of AKI, leading to higher mortality. The cause and effect relationship needs further analysis.

Pneumomediastinum in patients with SARS-CoV-2 treated with non-invasive ventilation.

SARS-CoV-2, causing the pandemic COVID-19, has rapidly spread, overwhelming healthcare systems. Non-invasive positive pressure ventilation (NIV) can be used as a bridging therapy to delay invasive mechanical ventilation or as a standalone therapy. Spontaneous pneumomediastinum is rare and self-limiting, but there is an increased incidence documented in COVID-19.Here we document two cases of pneumomediastinum-related prolonged NIV therapy in severe COVID-19. Patient 1, a 64-year-old man, who developed symptoms after NIV therapy was weaned and survived. Patient 2, an 82-year-old woman, failed to improve despite NIV therapy, on investigation was found to have a pneumomediastinum. After review, the patient was placed on best supportive care and died 3 days later.We highlight the importance of recognising less common causes of deterioration in severe COVID-19 treated with NIV. In addition, pneumomediastinum in these cases may not always lead to poor outcomes.

Iatrogenic Pneumothorax and Pneumomediastinum in a Patient with COVID-19.

Co-occurrence of pneumothorax and pneumomediastinum is rare in COVID-19 patients. Positive airway pressure therapy used to improve oxygenation may sometimes worsen clinical outcomes in some patients with severe COVID-19 pneumonia. In this case report, we describe an individual who was diagnosed with COVID-19 and developed bilateral pneumothorax and pneumomediastinum after initiating non-invasive positive airway pressure therapy.

Expectant management of pneumothorax in intubated COVID-19 positive patients: a case series.

BACKGROUND: There is an increasing amount of literature describing the pathogenesis of coronavirus disease 2019 (COVID-19) pneumonia and its associated complications. Historically, a small pneumothorax has been shown to be successfully treated without chest tube insertion, but this management has yet to be proven in COVID-19 pneumonia patients. In addition, pneumothorax in an intubated patient with high positive end-expiratory pressure (PEEP) provides additional uncertainty with pursuing non-operative management. CASE PRESENTATION: In this series we report four cases of patients with respiratory distress who tested positive for COVID-19 via nasopharyngeal swab and developed ventilator-induced pneumothoraces which were successfully managed with observation alone. CONCLUSIONS: Management of patients with COVID-19 pneumonia on positive pressure ventilation who develop small stable pneumothoraces can be safely observed without chest tube insertion.