High-Dose Inhaled Nitric Oxide in Acute Hypoxemic Respiratory Failure Due to COVID-19: A Multicenter Phase II Trial

Rationale: The effects of high-dose inhaled nitric oxide on hypoxemia in coronavirus disease (COVID-19) acute respiratory failure are unknown. Objectives: The primary outcome was the change in arterial oxygenation (PaO2/FiO2) at 48 hours. The secondary outcomes included: time to reach a PaO2/FiO2.300mmHg for at least 24 hours, the proportion of participants with a PaO2/FiO2.300mmHg at 28 days, and survival at 28 and at 90 days. Methods: Mechanically ventilated adults with COVID-19 pneumonia were enrolled in a phase II, multicenter, single-blind, randomized controlled parallel-arm trial. Participants in the intervention arm received inhaled nitric oxide at 80 ppm for 48 hours, compared with the control group receiving usual care (without placebo). Measurements and Main Results: A total of 193 participants were included in the modified intention-to-treat analysis. The mean change in PaO2/FiO2 ratio at 48 hours was 28.3mmHg in the intervention group and 21.4mmHg in the control group (mean difference, 39.1mmHg; 95% credible interval [CrI], 18.1 to 60.3). The mean time to reach a PaO2/FiO2.300mmHg in the interventional group was 8.7 days, compared with 8.4 days for the control group (mean difference, 0.44; 95% CrI, 23.63 to 4.53). At 28 days, the proportion of participants attaining a PaO2/FiO2.300mmHg was 27.7% in the inhaled nitric oxide group and 17.2% in the control subjects (risk ratio, 2.03; 95% CrI, 1.11 to 3.86). Duration of ventilation and mortality at 28 and 90 days did not differ. No serious adverse events were reported. Conclusions: The use of high-dose inhaled nitric oxide resulted in an improvement of PaO2/FiO2 at 48 hours compared with usual care in adults with acute hypoxemic respiratory failure due to COVID-19.

Pronation Reveals a Heterogeneous Response of Global and Regional Respiratory Mechanics in Patients With Acute Hypoxemic Respiratory Failure

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.

High-flow nasal oxygenation during gastrointestinal endoscopy. Systematic review and meta-analysis

Background

The use of high-flow nasal oxygen (HFNO) has the potential to improve patient safety by limiting hypoxaemia during gastrointestinal endoscopy. The degree of benefit is not adequately established.

Methods

English language literature searches of PubMed, Scopus, Web of Science, and Cochrane Library electronic databases were performed to identify randomised controlled trials comparing HFNO and conventional oxygen therapy (COT) for patients undergoing gastrointestinal endoscopy under deep sedation. The primary endpoint was the incidence of hypoxic events observed during endoscopic procedures. The secondary endpoints were the incidence of recourse to rescue manoeuvres, procedure interruption, and adverse events. A meta-analysis and a post hoc trial sequence analysis were performed.

Results

A total of 2867 patients from six randomised controlled trials were considered. Desaturation was observed in 5.2% and 27.2% of patients receiving HFNO and COT, respectively. Desaturation <90% was observed in 1.8% and 12.6% of the patients receiving HFNO and COT, respectively. In the subgroup analysis, desaturation occurrence was lower during HFNO than during COT in non-obese patients (2.2% vs 25.2%) and obese patients (22.9% vs 43.3%). Desaturation occurrence was lower during maximum (3.6% vs 26.9%) and minimum (15.9% vs 29.8%) HFNO therapy than during COT. HFNO showed a lower recurrence to rescue manoeuvres rate (4.7% vs 34.3%), a lower procedure interruption rate (0.4% vs 6.7%), and a lower adverse events rate (18.7% vs 21%) than COT. A high level of heterogeneity between the studies precluded confidence in drawing inference from the meta-analysis.

Conclusions

The evidence reviewed suggests that compared with COT, HFNO has fewer hypoxaemic events during gastrointestinal endoscopy, but this may not apply to all patients and clinical scenarios.

High-Dose Nitric Oxide From Pressurized Cylinders and Nitric Oxide Produced by an Electric Generator From Air

BACKGROUND

High-dose (≥ 80 ppm) inhaled nitric oxide (INO) has antimicrobial effects. We designed a trial to test the preventive effects of high-dose NO on coronavirus disease 2019 (COVID-19) in health care providers working with patients with COVID-19. The study was interrupted prematurely due to the introduction of COVID-19 vaccines for health care professionals. We thereby present data on safety and feasibility of breathing 160 ppm NO using 2 different NO sources, namely pressurized nitrogen/NO cylinders (INO) and electric NO (eNO) generators.

METHODS

NO gas was inhaled at 160 ppm in air for 15 min twice daily, before and after each work shift, over 14 d by health care providers (NCT04312243). During NO administration, vital signs were continuously monitored. Safety was assessed by measuring transcutaneous methemoglobinemia (SpMet) and the inhaled nitrogen dioxide (NO₂) concentration.

RESULTS

Twelve healthy health care professionals received a collective total of 185 administrations of high-dose NO (160 ppm) for 15 min twice daily. One-hundred and seventy-one doses were delivered by INO and 14 doses by eNO. During NO administration, SpMet increased similarly in both groups (P = .82). Methemoglobin decreased in all subjects at 5 min after discontinuing NO administration. Inhaled NO₂ concentrations remained between 0.70 ppm (0.63-0.79) and 0.75 ppm (0.67-0.83) in the INO group and between 0.74 ppm (0.68-0.78) and 0.88 ppm (0.70-0.93) in the eNO group. During NO administration, peripheral oxygen saturation and heart rate did not change. No adverse events occurred.

CONCLUSIONS

This pilot study testing high-dose INO (160 ppm) for 15 min twice daily using eNO seems feasible and similarly safe when compared with INO.

The impact of frailty on mortality in older patients admitted to an Intensive Care Unit

OBJECTIVE

Frailty is a relatively new concept for intensivists, and is defined as a status of increased vulnerability to stressors associated with reduced reserve and function of different physiological systems. Supporting the hypothesis that frailty may be an important predictor of poor prognosis among older patients admitted to Intensive Care Unit (ICU), this study seeks to evaluate the association between frailty at ICU admission and short and long-term mortality.

DESIGN

An unmatched case-control study was carried out.

SETTING

Intensive Care Unit.

PATIENTS OR PARTICIPANTS

Patients≥80 years of age admitted to the ICU for medical reasons.

INTERVENTIONS

None.

MAIN VARIABLES OF INTEREST

The primary outcome was 30-day mortality, while secondary outcomes were ICU mortality and mortality at one year.

RESULTS

Most of the patients were classified as frail at ICU admission (55.3%). The prevalence of frailty was higher among those who died than in those who were alive within 30 days from ICU admission (62.3% vs 48.3%, p=0.01). One-year mortality was higher in frail (84.4%) than in non-frail patients (65.2%, p<0.001). In the logistic regression analysis, after adjusting for potential confounders such as chronic diseases, clinical complexity, cause of ICU admission and use of advanced procedures, frailty was seen to be significantly associated to one-year mortality, but not with ICU mortality or 30-day mortality.

DISCUSSION

The admission of geriatric patients to the ICU is increasing. Frailty assessment may play an important role in the clinical evaluation of such individuals for triage, but should not be considered a priori as an exclusion criterion for admission.

Inhaled high dose nitric oxide is a safe and effective respiratory treatment in spontaneous breathing hospitalized patients with COVID-19 pneumonia

BACKGROUND

Inhaled nitric oxide (NO) is a selective pulmonary vasodilator. In-vitro studies report that NO donors can inhibit replication of SARS-CoV-2. This multicenter study evaluated the feasibility and effects of high-dose inhaled NO in non-intubated spontaneously breathing patients with Coronavirus disease-2019 (COVID-19).

METHODS

This is an interventional study to determine whether NO at 160 parts-per-million (ppm) inhaled for 30 min twice daily might be beneficial and safe in non-intubated COVID-19 patients.

RESULTS

Twenty-nine COVID-19 patients received a total of 217 intermittent inhaled NO treatments for 30 min at 160 ppm between March and June 2020. Breathing NO acutely decreased the respiratory rate of tachypneic patients and improved oxygenation in hypoxemic patients. The maximum level of nitrogen dioxide delivered was 1.5 ppm. The maximum level of methemoglobin (MetHb) during the treatments was 4.7%. MetHb decreased in all patients 5 min after discontinuing NO administration. No adverse events during treatment, such as hypoxemia, hypotension, or acute kidney injury during hospitalization occurred. In our NO treated patients, one patient of 29 underwent intubation and mechanical ventilation, and none died. The median hospital length of stay was 6 days [interquartile range 4-8]. No discharged patients required hospital readmission nor developed COVID-19 related long-term sequelae within 28 days of follow-up.

CONCLUSIONS

In spontaneous breathing patients with COVID-19, the administration of inhaled NO at 160 ppm for 30 min twice daily promptly improved the respiratory rate of tachypneic patients and systemic oxygenation of hypoxemic patients. No adverse events were observed. None of the subjects was readmitted or had long-term COVID-19 sequelae.

A Novel Inhalation Mask System to Deliver High Concentrations of Nitric Oxide Gas in Spontaneously Breathing Subjects

Nitric Oxide (NO) is administered as gas for inhalation to induce selective pulmonary vasodilation. It is a safe therapy, with few potential risks even if administered at high concentration. Inhaled NO gas is routinely used to increase systemic oxygenation in different disease conditions. The administration of high concentrations of NO also exerts a virucidal effect in vitro. Owing to its favorable pharmacodynamic and safety profiles, the familiarity in its use by critical care providers, and the potential for a direct virucidal effect, NO is clinically used in patients with coronavirus disease-2019 (COVID-19). Nevertheless, no device is currently available to easily administer inhaled NO at concentrations higher than 80 parts per million (ppm) at various inspired oxygen fractions, without the need for dedicated, heavy, and costly equipment. The development of a reliable, safe, inexpensive, lightweight, and ventilator-free solution is crucial, particularly for the early treatment of non-intubated patients outside of the intensive care unit (ICU) and in a limited-resource scenario. To overcome such a barrier, a simple system for the non-invasive NO gas administration up to 250 ppm was developed using standard consumables and a scavenging chamber. The method has been proven safe and reliable in delivering a specified NO concentration while limiting nitrogen dioxide levels. This paper aims to provide clinicians and researchers with the necessary information on how to assemble or adapt such a system for research purposes or clinical use in COVID-19 or other diseases in which NO administration might be beneficial.

The impact of frailty on mortality in older patients admitted to an Intensive Care Unit

OBJECTIVE

Frailty is a relatively new concept for intensivists, and is defined as a status of increased vulnerability to stressors associated with reduced reserve and function of different physiological systems. Supporting the hypothesis that frailty may be an important predictor of poor prognosis among older patients admitted to Intensive Care Unit (ICU), this study seeks to evaluate the association between frailty at ICU admission and short and long-term mortality.

DESIGN

An unmatched case-control study was carried out.

SETTING

Intensive Care Unit.

PATIENTS OR PARTICIPANTS

Patients≥80 years of age admitted to the ICU for medical reasons.

INTERVENTIONS

None.

MAIN VARIABLES OF INTEREST

The primary outcome was 30-day mortality, while secondary outcomes were ICU mortality and mortality at one year.

RESULTS

Most of the patients were classified as frail at ICU admission (55.3%). The prevalence of frailty was higher among those who died than in those who were alive within 30 days from ICU admission (62.3% vs 48.3%, p=0.01). One-year mortality was higher in frail (84.4%) than in non-frail patients (65.2%, p<0.001). In the logistic regression analysis, after adjusting for potential confounders such as chronic diseases, clinical complexity, cause of ICU admission and use of advanced procedures, frailty was seen to be significantly associated to one-year mortality, but not with ICU mortality or 30-day mortality.

DISCUSSION

The admission of geriatric patients to the ICU is increasing. Frailty assessment may play an important role in the clinical evaluation of such individuals for triage, but should not be considered a priori as an exclusion criterion for admission.

Protocol of a randomized controlled trial testing inhaled Nitric Oxide in mechanically ventilated patients with severe acute respiratory syndrome in COVID-19 (SARS-CoV-2)

Introduction

Severe acute respiratory syndrome due to novel Coronavirus (SARS-CoV-2) related infection (COVID-19) is characterized by severe ventilation perfusion mismatch leading to refractory hypoxemia. To date, there is no specific treatment available for COVID-19. Nitric oxide is a selective pulmonary vasodilator gas used as a rescue therapy in refractory hypoxemia due to acute respiratory distress syndrome (ARDS). In has also shown invitro and clinical evidence that inhaled nitric oxide gas (iNO) has antiviral activity against other strains of coronavirus. The primary aim of this study is to determine whether inhaled NO improves oxygenation in patients with hypoxic COVID-19. This is a multicenter randomized controlled trial with 1:1 individual allocation. Patients will be blinded to the treatment.

Methods and analysis

Intubated patients admitted to the intensive care unit with confirmed SARS-CoV-2 infection and severe hypoxemia will be randomized to receive inhalation of NO (treatment group) or not (control group). Treatment will be stopped when patients are free from hypoxemia for more than 24 hours. The primary outcome evaluates levels of oxygenation between the two groups at 48 hours. Secondary outcomes include rate of survival rate at 28 and 90 days in the two groups, time to resolution of severe hypoxemia, time to achieve negativity of SARS-CoV-2 RT-PCR tests.

Ethics and dissemination

The study protocol has been approved by the Investigational Review Board of Xijing Hospital (Xi'an, China) and by the Partners Human Research Committee (Boston, USA). Recruitment will start after approval of both IRBs and local IRBs at other enrolling centers. Results of this study will be published in scientific journals, presented at scientific meetings, reported through flyers and posters, and published on related website or media in combating against this widespread contagious disease.

Trial registration

Clinicaltrials.gov. NCT04306393.

Protocol for a randomized controlled trial testing inhaled nitric oxide therapy in spontaneously breathing patients with COVID-19

Introduction

the current worldwide outbreak of Coronavirus disease 2019 (COVID-19) due to a novel coronavirus (SARS-CoV-2) is seriously threatening the public health. The number of infected patients is continuously increasing and the need for Intensive Care Unit admission ranges from 5 to 26%. The mortality is reported to be around 3.4% with higher values for the elderly and in patients with comorbidities. Moreover, this condition is challenging the healthcare system where the outbreak reached its highest value. To date there is still no available treatment for SARS-CoV-2. Clinical and preclinical evidence suggests that nitric oxide (NO) has a beneficial effect on the coronavirus-mediated acute respiratory syndrome, and this can be related to its viricidal effect. The time from the symptoms' onset to the development of severe respiratory distress is relatively long. We hypothesize that high concentrations of inhaled NO administered during early phases of COVID-19 infection can prevent the progression of the disease.

Methods and analysis

This is a multicenter randomized controlled trial. Spontaneous breathing patients admitted to the hospital for symptomatic COVID-19 infection will be eligible to enter the study. Patients in the treatment group will receive inhaled NO at high doses (140-180 parts per million) for 30 minutes, 2 sessions every day for 14 days in addition to the hospital care. Patient in the control group will receive only hospital care. The primary outcome is the percentage of patients requiring endotracheal intubation due to the progression of the disease in the first 28 days from enrollment in the study. Secondary outcomes include mortality at 28 days, proportion of negative test for SARS-CoV-2 at 7 days and time to clinical recovery.

Ethics and dissemination

The trial protocol has been approved at the Investigation Review Boards of Xijing Hospital (Xi'an, China) and The Partners Human Research Committee of Massachusetts General Hospital (Boston, USA) is pending. Recruitment is expected to start in March 2020. Results of this study will be published in scientific journals, presented at scientific meetings, and on related website or media in fighting this widespread contagious disease.