(1) The use of high-flow nasal cannula (HFNC) combined with frequent respiratory monitoring in patients with acute hypoxic respiratory failure due to COVID-19 has been shown to reduce intubation and mechanical ventilation. (2) This prospective, single-center, observational study included consecutive adult patients with COVID-19 pneumonia treated with a high-flow nasal cannula. Hemodynamic parameters, respiratory rate, inspiratory fraction of oxygen (FiO2), saturation of oxygen (SpO2), and the ratio of oxygen saturation to respiratory rate (ROX) were recorded prior to treatment initiation and every 2 h for 24 h. A 6-month follow-up questionnaire was also conducted. (3) Over the study period, 153 of 187 patients were eligible for HFNC. Of these patients, 80% required intubation and 37% of the intubated patients died in hospital. Male sex (OR = 4.65; 95% CI [1.28; 20.6], p = 0.03) and higher BMI (OR = 2.63; 95% CI [1.14; 6.76], p = 0.03) were associated with an increased risk for new limitations at 6-months after hospital discharge. (4) 20% of patients who received HFNC did not require intubation and were discharged alive from the hospital. Male sex and higher BMI were associated with poor long-term functional outcomes.

OBJECTIVES:. Experimental models suggest that prone position and positive end-expiratory pressure (PEEP) homogenize ventral–dorsal ventilation distribution and regional respiratory compliance. However, this response still needs confirmation on humans. Therefore, this study aimed to assess the changes in global and regional respiratory mechanics in supine and prone positions over a range of PEEP levels in acute respiratory distress syndrome (ARDS) patients. DESIGN:. A prospective cohort study. PATIENTS:. Twenty-two intubated patients with ARDS caused by COVID-19 pneumonia. INTERVENTIONS:. Electrical impedance tomography and esophageal manometry were applied during PEEP titrations from 20 cm H2O to 6 cm H2O in supine and prone positions. MEASUREMENTS:. Global respiratory system compliance (Crs), chest wall compliance, regional lung compliance, ventilation distribution in supine and prone positions. MAIN RESULTS:. Compared with supine position, the maximum level of Crs changed after prone position in 59% of ARDS patients (n = 13), of which the Crs decreased in 32% (n = 7) and increased in 27% (n = 6). To reach maximum Crs after pronation, PEEP was changed in 45% of the patients by at least 4 cm H2O. After pronation, the ventilation and compliance of the dorsal region did not consistently change in the entire sample of patients, increasing specifically in a subgroup of patients who showed a positive change in Crs when transitioning from supine to prone position. These combined changes in ventilation and compliance suggest dorsal recruitment postpronation. In addition, the subgroup with increased Crs postpronation demonstrated the most pronounced difference between dorsal and ventral ventilation distribution from supine to prone position (p = 0.01), indicating heterogeneous ventilation distribution in prone position. CONCLUSIONS:. Prone position modifies global respiratory compliance in most patients with ARDS. Only a subgroup of patients with a positive change in Crs postpronation presented a consistent improvement in dorsal ventilation and compliance. These data suggest that the response to pronation on global and regional mechanics can vary among ARDS patients, with some patients presenting more dorsal lung recruitment than others.

OBJECTIVE:To evaluate whether the use of inhaled nitric oxide (iNO)200 improves respiratory function.METHODS:This retrospective cohort study used data from pregnant patients hospitalized with severe bilateral coronavirus disease 2019 (COVID-19) pneumonia at four teaching hospitals between March 2020 and December 2021. Two cohorts were identified: 1) those receiving standard of care alone (SoC cohort) and 2) those receiving iNO200 for 30 minutes twice daily in addition to standard of care alone (iNO200 cohort). Inhaled nitric oxide, as a novel therapy, was offered only at one hospital. The prespecified primary outcome was days free from any oxygen supplementation at 28 days postadmission. Secondary outcomes were hospital length of stay, rate of intubation, and intensive care unit (ICU) length of stay. The multivariable-adjusted regression analyses accounted for age, body mass index, gestational age, use of steroids, remdesivir, and the study center.RESULTS:Seventy-one pregnant patients were hospitalized for severe bilateral COVID-19 pneumonia: 51 in the SoC cohort and 20 in the iNO200 cohort. Patients receiving iNO200 had more oxygen supplementation-free days (iNO200: median [interquartile range], 24 [23-26] days vs standard of care alone: 22 [14-24] days, P=.01) compared with patients in the SoC cohort. In the multivariable-adjusted analyses, iNO200 was associated with 63.2% (95% CI 36.2-95.4%; P<.001) more days free from oxygen supplementation, 59.7% (95% CI 56.0-63.2%; P<.001) shorter ICU length of stay, and 63.6% (95% CI 55.1-70.8%; P<.001) shorter hospital length of stay. No iNO200-related adverse events were reported.CONCLUSION:In pregnant patients with severe bilateral COVID-19 pneumonia, iNO200 was associated with a reduced need for oxygen supplementation and shorter hospital stay.

The administration of exogenous oxygen to support adequate gas exchange is the cornerstone of respiratory care. In the past few years, other gaseous molecules have been introduced in clinical practice to treat the wide variety of physiological derangement seen in critical care patients.Inhaled nitric oxide (NO) is used for its unique selective pulmonary vasodilator effect. Recent studies showed that NO plays a pivotal role in regulating ischemia-reperfusion injury and it has antibacterial and antiviral activity.Helium, due to its low density, is used in patients with upper airway obstruction and lower airway obstruction to facilitate gas flow and to reduce work of breathing.Carbon monoxide (CO) is a poisonous gas that acts as a signaling molecule involved in many biologic pathways. CO's anti-inflammatory and antiproliferative effects are under investigation in the setting of acute respiratory distress and idiopathic pulmonary fibrosis.Inhaled anesthetics are widely used in the operative room setting and, with the development of anesthetic reflectors, are now a valid option for sedation management in the intensive care unit.Many other gases such as xenon, argon, and hydrogen sulfide are under investigation for their neuroprotective and cardioprotective effects in post-cardiac arrest syndrome.With all these therapeutic options available, the clinician must have a clear understanding of the physiologic basis, therapeutic potential, and possible adverse events of these therapeutic gases. In this review, we will present the therapeutic gases other than oxygen used in clinical practice and we will describe other promising therapeutic gases that are in the early phases of investigation.

Background: The prone position and lung protective ventilation are the only interventions to improve survival in ARDS patients. Due to early reports during the COVID-19 pandemic showing dramatic improvements in oxygenation, the use of prone position has been broadly adopted in intubated patients around the globe. However, it remains unclear whether titration of ventilation should be reassessed when the patient is repositioned. To our knowledge, respiratory compliance (CRS) comparisons during supine and prone positions have been described in patients only at predefined levels of PEEP. Therefore, the objective of this study was to characterize the response of respiratory mechanics in supine and prone positions during a decremental PEEP trial in COVID-19 related ARDS patients. Methods: We studied a cohort of patients with COVID-19 related ARDS undergoing invasive mechanical ventilation. The study was approved by the local IRBs. Patients were ventilated with a tidal volume of 5–6 mL/kg PBW. A decremental PEEP trial was performed. Airway pressures and flow were recorded in supine and prone positions to calculate CRS. Ventilation distribution was measured by electrical impedance tomography (EIT) in three gravitational regions (ROI). Results: We included 14 patients with COVID-19 related ARDS. The cohort’s median age was 65 y (IQR 59–69) with a BMI of 32.5 (IQR 28–35). After 24 h of intubation, median PaO2/FIO2 was 151 mm Hg (IQR 105–170) and PEEP was 10 cm H2O (IQR 10–14). Figure 1-A, B, and C illustrate, respectively, patients whose maximum CRS was reduced, similar, or increased after pronation at a certain level of PEEP. The PEEP to obtain the maximum CRS was lower in prone compared to supine position in 14/20 (70%) patients (Figure 1-D). Changes in CRS after pronation had symmetrical distribution (Figure 1-E). The maximum CRS was reached with higher ventilation distribution in the non-dependent zone in prone position (~35%). Conclusions: In a cohort of mechanically ventilated patients with severe COVID-19 related ARDS, a subset of patients demonstrated a marked improvement in lung mechanics after pronation, with a resultant best PEEP for the highest compliance being lower in prone versus supine. Ventilation distribution was shifted to dorsal-predominant from ventral-predominant in prone position and correlates with changes in CRS. These results suggest that PEEP titration would be prudent to perform after prone positioning.

Background: High-flow nasal cannula has been suggested to reduce endotracheal intubation in hypoxic acute respiratory failure and ventilator usage during the coronavirus disease 2019 (COVID-19) pandemic. In this study, we characterize the prevalence and clinical features of patients with COVID-19 treated with HFNC, define factors associated with HFNC failure, and describe the respiratory mechanics after intubation. Methods: We performed a single-center prospective observational study on COVID-19 patients with respiratory failure who failed the conventional oxygen (O2) therapy from September 2020 and April 2021. This study was approved by the local IRB. The decision to start the HFNC was made following the institutional protocol. We collected data on demographics, past medical history and laboratory results, vital signs, and ROX index (defined as peripherical saturation of O2/inspired fraction of O2/respiratory rate) during HFNC treatment and entire HFNC time use. Tracheal intubation decision was made by the clinicians caring for the patient. If intubation occurred, we recorded data about compliance of the respiratory system (CRS) and oxygenation at intubation and 24 h later. Results: We enrolled 153 patients. Hospital mortality was 29% and associated with the presence of hypertension, chronic kidney disease (CKD), coronary artery disease (CAD), and advanced age. 19% of the patients were successfully weaned from HFNC. Diabetes was associated with an increased risk of HFNC failure. ROX index > 4 at 6 and 12 h after the initiation of HFNC was respectively 75% and 90% sensitive for detecting patients who will be successfully weaned from HFNC. FIO2 during HFNC was statistically higher in the intubated group. After intubation, the CRS was statistically different between the deceased (mean 30 mL/cm H2O) compared with the survivors (mean 36 mL/cm H2O), but PaO2/FIO2 ratio was not statistically different. Conclusions: In COVID-19 patients with respiratory failure who failed conventional O2 therapy, 19% receiving HFNC were never intubated. Predictive factors of HFNC failure were diabetes mellitus, ROX index lower than 4.88, and high FIO2 requirement. Age, hypertension, CAD, and CKD increased the risk of mortality. After intubation, the compliance was lower in deceased patients compared with the patients who survived. The severity of oxygenation index correlated with the increased likelihood of intubation but not with death.