Trial Outcomes & Findings for Safety Study of Inhaled Carbon Monoxide to Treat Pneumonia and Sepsis-Induced Acute Respiratory Distress Syndrome (ARDS) (NCT NCT04870125)

NCT ID: NCT04870125

Last Updated: 2026-05-26

Results Overview

This was assessed by comparing the measured 90-minute COHb level and the target COHb level of 6-8% post exposure. The limited number of measurements prevent the variance and measures of dispersion calculations; therefore we present the data from one available subject in the CO group and report as "Mean" without standard deviation, since measures of dispersion cannot be calculated.

Recruitment status

TERMINATED

Study phase

PHASE1

Target enrollment

5 participants

Primary outcome timeframe

Post exposure 90 min day 3

Results posted on

2026-05-26

Participant Flow

First recruited subject date was 12/6/2023 and last recruited subject was 5/22/2024. The study treatment was 3 days and follow up during 14 days during hospitalization and up to 6 months follow up. Screening was conducted in Intensive Care Units and qualifying subjects were consented by study physicians at Brigham and Women's Hospital. One subject consented but then withdrew from the study prior to any protocol procedures.

After consent. Subjects were randomized to either placebo or inhaled CO. Study procedures started the following day after randomization.

Participant milestones

Participant milestones
Measure
Inhaled Carbon Monoxide
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Overall Study
STARTED
2
2
Overall Study
COMPLETED
2
2
Overall Study
NOT COMPLETED
0
0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Safety Study of Inhaled Carbon Monoxide to Treat Pneumonia and Sepsis-Induced Acute Respiratory Distress Syndrome (ARDS)

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure
Inhaled Carbon Monoxide
n=2 Participants
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
n=2 Participants
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Total
n=4 Participants
Total of all reporting groups
Age, Categorical
<=18 years
0 Participants
n=20 Participants
0 Participants
n=32 Participants
0 Participants
n=64 Participants
Age, Categorical
Between 18 and 65 years
2 Participants
n=20 Participants
1 Participants
n=32 Participants
3 Participants
n=64 Participants
Age, Categorical
>=65 years
0 Participants
n=20 Participants
1 Participants
n=32 Participants
1 Participants
n=64 Participants
Sex: Female, Male
Female
1 Participants
n=20 Participants
2 Participants
n=32 Participants
3 Participants
n=64 Participants
Sex: Female, Male
Male
1 Participants
n=20 Participants
0 Participants
n=32 Participants
1 Participants
n=64 Participants
Race (NIH/OMB)
American Indian or Alaska Native
0 Participants
n=20 Participants
0 Participants
n=32 Participants
0 Participants
n=64 Participants
Race (NIH/OMB)
Asian
0 Participants
n=20 Participants
0 Participants
n=32 Participants
0 Participants
n=64 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants
n=20 Participants
0 Participants
n=32 Participants
0 Participants
n=64 Participants
Race (NIH/OMB)
Black or African American
0 Participants
n=20 Participants
1 Participants
n=32 Participants
1 Participants
n=64 Participants
Race (NIH/OMB)
White
2 Participants
n=20 Participants
1 Participants
n=32 Participants
3 Participants
n=64 Participants
Race (NIH/OMB)
More than one race
0 Participants
n=20 Participants
0 Participants
n=32 Participants
0 Participants
n=64 Participants
Race (NIH/OMB)
Unknown or Not Reported
0 Participants
n=20 Participants
0 Participants
n=32 Participants
0 Participants
n=64 Participants
Ethnicity (NIH/OMB)
Hispanic or Latino
0 Participants
n=20 Participants
0 Participants
n=32 Participants
0 Participants
n=64 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
2 Participants
n=20 Participants
2 Participants
n=32 Participants
4 Participants
n=64 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
0 Participants
n=20 Participants
0 Participants
n=32 Participants
0 Participants
n=64 Participants
Baseline Critical Illness Category
ARDS with Sepsis
1 Participants
n=20 Participants
2 Participants
n=32 Participants
3 Participants
n=64 Participants
Baseline Critical Illness Category
Pneumonia with sepsis, without ARDS
1 Participants
n=20 Participants
0 Participants
n=32 Participants
1 Participants
n=64 Participants
Baseline Critical Illness Category
Pneumonia without ARDS or sepsis
0 Participants
n=20 Participants
0 Participants
n=32 Participants
0 Participants
n=64 Participants

PRIMARY outcome

Timeframe: 7 days

Population: All subjects were analyzed for safety measures.

Safety of inhaled CO, defined by the incidence of pre-specified administration-related AEs (as defined below) and spontaneously reported AEs through study day 7. 1. Acute myocardial infarction within 48 hours of study drug administration 2. Acute cerebrovascular accident (CVA) within 48 hours of study drug administration 3. New onset atrial or ventricular arrhythmia requiring DC cardioversion within 48 hours of study drug administration 4. Increased oxygenation requirements defined as: an increase in FiO2 of ≥ 0.2 AND increase in PEEP ≥ 5 cm H2O within 6 hours of study drug administration 5. Increase in COHb ≥ 10% 6. Increase in lactate by ≥ 2 mmol/L within 6 hours of study drug administration

Outcome measures

Outcome measures
Measure
Inhaled Carbon Monoxide
n=2 Participants
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
n=2 Participants
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Primary Safety Outcome: Number of Pre-specified Administration-related Adverse Events (AEs).
Acute myocardial infarction within 48 hours of study drug administration · No Acute myocardial infarction within 48 hours of study drug administration
0 Participants
0 Participants
Primary Safety Outcome: Number of Pre-specified Administration-related Adverse Events (AEs).
Acute cerebrovascular accident (CVA) within 48 hours of study drug administration · No Acute myocardial infarction within 48 hours of study drug administration
0 Participants
0 Participants
Primary Safety Outcome: Number of Pre-specified Administration-related Adverse Events (AEs).
New arrhythmia requiring DC cardioversion within 48 hours of study drug administration · No Acute myocardial infarction within 48 hours of study drug administration
0 Participants
0 Participants
Primary Safety Outcome: Number of Pre-specified Administration-related Adverse Events (AEs).
Increased oxygenation: increased FiO2 ≥ 0.2 AND PEEP ≥ 5 cm H2O within 6 hrs of drug administration · No Acute myocardial infarction within 48 hours of study drug administration
0 Participants
0 Participants
Primary Safety Outcome: Number of Pre-specified Administration-related Adverse Events (AEs).
Increase in COHb ≥ 10% · No Acute myocardial infarction within 48 hours of study drug administration
0 Participants
0 Participants
Primary Safety Outcome: Number of Pre-specified Administration-related Adverse Events (AEs).
Increase in lactate by ≥ 2 mmol/L within 6 hours of study drug administration · No Acute myocardial infarction within 48 hours of study drug administration
0 Participants
0 Participants

PRIMARY outcome

Timeframe: Post exposure 90 min day 1

Population: Percentage change in measured COHb from targeted range.

This was assessed by comparing the measured 90-minute COHb level and the target COHb level of 6-8% post exposure. We present average data from the two available subjects in the CO group and report as "Mean" with standard deviation.

Outcome measures

Outcome measures
Measure
Inhaled Carbon Monoxide
n=2 Participants
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Percentage Change Measured Relative to Target COHb Level
0.111567174 Average % change from predicted 90min
Standard Deviation 0.354200664

PRIMARY outcome

Timeframe: Post exposure 90 min day 2

Population: The percent change in measured COHb from targeted range.

This was assessed by comparing the measured 90-minute COHb level and the target COHb level of 6-8% post exposure. The limited number of measurements prevent the variance and measures of dispersion calculations; therefore we present the data from one available subject in the CO group and report as "Mean" without standard deviation, since measures of dispersion cannot be calculated.

Outcome measures

Outcome measures
Measure
Inhaled Carbon Monoxide
n=1 Participants
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Variance of Measured Relative to Target COHb Level
0.258084259 % change from predicted 90min
Standard Deviation NA
Not calculable for a single participant

PRIMARY outcome

Timeframe: Post exposure 90 min day 3

Population: The percent change in measured COHb from targeted range.

This was assessed by comparing the measured 90-minute COHb level and the target COHb level of 6-8% post exposure. The limited number of measurements prevent the variance and measures of dispersion calculations; therefore we present the data from one available subject in the CO group and report as "Mean" without standard deviation, since measures of dispersion cannot be calculated.

Outcome measures

Outcome measures
Measure
Inhaled Carbon Monoxide
n=1 Participants
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Variance of Measured Relative to Target COHb Level
0.308046473 % change from predicted 90min
Standard Deviation NA
Not calculable for a single participant

SECONDARY outcome

Timeframe: 5 days

The Lung Injury Score (LIS) is a composite 4-point scoring system including the PaO2/FiO2, PEEP, quasi-static respiratory compliance, and the extent of infiltrates on the chest X-ray. Each of the four components is categorized from 0 to 4, where a higher number is worse. The total Lung Injury Score is obtained by dividing the aggregate sum by the number of components used. Previous randomized clinical trials in ARDS have shown that a decreased LIS correlates with improvement in lung physiology as well as important clinical outcomes including mortality and ventilator-free days (VFDs). The number presented is the average difference from beginning to end of treatment. We present the average of data from the 2 available subjects in each group and report as "Mean" with standard deviation.

Outcome measures

Outcome measures
Measure
Inhaled Carbon Monoxide
n=2 Participants
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
n=2 Participants
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Lung Injury Score (LIS) on Days 1-5 Days
16.75 Percent change in Lung Injury Score
Standard Deviation 23.68
-8.25 Percent change in Lung Injury Score
Standard Deviation 35.00

SECONDARY outcome

Timeframe: Baseline to day 5

Population: We are providing percent change in PaO2/FiO2 ratio from baseline or day 1 to day 5.

PaO2/FiO2 was to be measured on days 1-5 in ventilated subjects. We are providing percent change in PaO2/FiO2 ratio from baseline to day 5. We present the average of data from the 2 available subjects in each group and report as "Mean" with standard deviation.

Outcome measures

Outcome measures
Measure
Inhaled Carbon Monoxide
n=2 Participants
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
n=2 Participants
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Percent Change in PaO2/FiO2 Ratio Between Baseline and Day 5
43.42 Percent change in SaO2/FiO2 ratio
Standard Deviation 27.25
58.54 Percent change in SaO2/FiO2 ratio
Standard Deviation 130.03

SECONDARY outcome

Timeframe: 5 days

Population: We provide change in Oi from baseline. Oi is only measured when subjects are ventilated, therefore not all timepoints are available. Limited number of subjects precludes further analyses.

The oxygenation index will be measured on days 1-5 in ventilated subjects. Oxygenation index is calculated as (FiO2 X mean airway pressure)/PaO2. We provide change in Oi from baseline. Oi is only measured when subjects are ventilated, therefore not all timepoints are available. Limited number of measurements prevents variance and measures of dispersion analyses; therefore we present the data from the subjects available in each group and report as "Mean" without standard deviation, where measures of dispersion cannot be calculated.

Outcome measures

Outcome measures
Measure
Inhaled Carbon Monoxide
n=1 Participants
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
n=2 Participants
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Oxygenation Index (OI) on Days 1-5 Days
-41.76 Percent change in O2 index from baseline
Standard Deviation NA
Not calculable for a single participant
-18.04 Percent change in O2 index from baseline
Standard Deviation 25.66

SECONDARY outcome

Timeframe: Day 3

Population: We present change in dead space fraction between initial and final measurements that were available (measurements only taken while the subjects were intubated).

The dead space fraction will be measured days 1-3 in ventilated subjects. We present change in dead space fraction between initial and final measurements that were available (measurements only taken while the subjects were intubated). We present the data from the subjects available in each group and report as "Mean" with standard deviation.

Outcome measures

Outcome measures
Measure
Inhaled Carbon Monoxide
n=2 Participants
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
n=2 Participants
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Dead Space Fraction (Vd/Vt) on Days 1-3
5.46 Percent change in Dead Space
Standard Deviation 9.46
-4.91 Percent change in Dead Space
Standard Deviation 4.59

SECONDARY outcome

Timeframe: 1-5 days

Population: We present changes in SOFA score over the time of hospitalization, over the time of ICU admission (up to days 3 and 5 for the enrolled subjects).

Organ failure will be assessed using the SOFA score. SOFA scores will be assessed daily on days 1-5, as the SOFA score has been shown to be a reliable prognostic indicator of outcomes in critically ill patients. To calculate the Sequential Organ Failure Assessment (SOFA) score, each of the six components (Respiratory, Coagulation, Liver, Cardiovascular, Central Nervous System, Renal) is categorized from 0-4, where a higher number is worse. The SOFA score (0-24) will be calculated by summing all six components. We present changes in SOFA score over the time of hospitalization, over the time of ICU admission (up to days 3 and 5 for the enrolled subjects). We present the data from the subjects available in each group and report as "Mean" with standard deviation.

Outcome measures

Outcome measures
Measure
Inhaled Carbon Monoxide
n=2 Participants
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
n=2 Participants
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Sequential Organ Failure Assessment (SOFA) Score on Days 1-5.
Percent change in SOFA score by day 3
-37.5 Percent change in SOFA score
Standard Deviation 88.38
-17.70 Percent change in SOFA score
Standard Deviation 1.47
Sequential Organ Failure Assessment (SOFA) Score on Days 1-5.
Percent change in SOFA score by day 5
-12.5 Percent change in SOFA score
Standard Deviation 123.74
-59.37 Percent change in SOFA score
Standard Deviation 57.45

SECONDARY outcome

Timeframe: 28 days

Population: We present data of ventilator free days for enrolled subjects. Note that one subject in the medical air group died at day 9.

Ventilator-free days to day 28 are defined as the number of days from the time of initiating unassisted breathing to day 28 after randomization, assuming survival for at least two consecutive calendar days after initiating unassisted breathing and continued unassisted breathing to day 28. If a subject returns to assisted breathing and subsequently achieves unassisted breathing to day 28, VFDs will be counted from the end of the last period of assisted breathing to day 28. Participants who do not survive to day 28 are assigned zero ventilator-free days. We present data of ventilator free days for enrolled subjects. Note that one subject in the medical air group died at day 9. We present the data from the subjects available in each group and report as "Mean" with standard deviation.

Outcome measures

Outcome measures
Measure
Inhaled Carbon Monoxide
n=2 Participants
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
n=2 Participants
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Ventilator-free Days at Day 28
20.5 Days
Standard Deviation 6.36
12 Days
Standard Deviation 16.97

SECONDARY outcome

Timeframe: 28 days

Population: We present average number of ICU free days. Please note that one subject in the medical air group died at day 9.

ICU-free days will be assessed on day 28. ICU-free days is defined as the number of days between randomization and day 28 in which the patient is in the ICU (for any part of a day). We present average number of ICU free days. Please note that one subject in the medical air group died at day 9. We present the data from the subjects available in each group and report as "Mean" with standard deviation.

Outcome measures

Outcome measures
Measure
Inhaled Carbon Monoxide
n=2 Participants
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
n=2 Participants
Inhaled Medical Air for up to 90 minutes daily for 3 days.
ICU-free Days at Day 28
20 Average number of ICU free Days
Standard Deviation 5.66
11 Average number of ICU free Days
Standard Deviation 15.56

SECONDARY outcome

Timeframe: 60 days

Population: We present hospital free days at day 60. Please note that one subject in the air group died at day 9.

Hospital-free days will be assessed on day 60. Hospital-free days are days alive post hospital discharge through day 60. Patients who die on or prior to day 60 are assigned zero hospital-free days. We present hospital free days at day 60. Please note that one subject in the air group died at day 9. We present the data from the subjects available in each group and report as "Mean" with standard deviation.

Outcome measures

Outcome measures
Measure
Inhaled Carbon Monoxide
n=2 Participants
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
n=2 Participants
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Hospital-free Days at Day 60
42.5 Number of Hospital free Days at day 60
Standard Deviation 9.19
26 Number of Hospital free Days at day 60
Standard Deviation 36.77

SECONDARY outcome

Timeframe: 60 days

Mortality will be assessed on day 28 and day 60.

Outcome measures

Outcome measures
Measure
Inhaled Carbon Monoxide
n=2 Participants
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
n=2 Participants
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Hospital Mortality to Day 28 and 60
Day 28
0 Participants
1 Participants
Hospital Mortality to Day 28 and 60
Day 60
0 Participants
1 Participants

SECONDARY outcome

Timeframe: 3 months

Montreal Cognitive Assessment - Blind Version (MoCA-Blind) The MoCA-Blind is a remote adaptation of the Montreal Cognitive Assessment (MoCA) used as a screening assessment for detecting cognitive impairment. It is administered via telephone interview. The MoCA-Blind assesses the following cognitive domains (points): * Attention (0-6) * Language: (0-3 (Repetition (0-2) and fluency (0-1)) * Abstraction (0-2) * Memory: Delayed recall (0-5) * Orientation (0-6) The minimum score is 0 and maximum score is 22 points. Calculated as the sum of all domains. Interpretation: Higher scores indicate better cognitive functioning. Lower scores indicate worse cognitive functioning (greater cognitive impairment). A score of 18 or above is within the normal range. A limited number of measurements prevents variance and dispersion analyses; therefore, we report available group data as "means" without standard deviation where dispersion cannot be calculated.

Outcome measures

Outcome measures
Measure
Inhaled Carbon Monoxide
n=2 Participants
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
n=1 Participants
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Montreal Cognitive Assessment- MoCA-Blind
21.5 scores on a scale
Standard Deviation 0.71
18 scores on a scale
Standard Deviation NA
Not calculable for a single participant

SECONDARY outcome

Timeframe: 6 months

Population: Please note that one of the CO subjects was alive and well at 6 months but declined participation in the MOCA test.

Montreal Cognitive Assessment - Blind Version (MoCA-Blind) The MoCA-Blind is a remote adaptation of the Montreal Cognitive Assessment (MoCA) used as a screening assessment for detecting cognitive impairment. It is administered via telephone interview. The MoCA-Blind assesses the following cognitive domains (points): * Attention (0-6) * Language: (0-3 (Repetition (0-2) and fluency (0-1)) * Abstraction (0-2) * Memory: Delayed recall (0-5) * Orientation (0-6) The minimum score is 0 and maximum score is 22 points. Calculated as the sum of all domains. Interpretation: Higher scores indicate better cognitive functioning. Lower scores indicate worse cognitive functioning (greater cognitive impairment). A score of 18 or above is within the normal range. A limited number of measurements prevents variance and dispersion analyses; therefore, we report available group data as "means" without standard deviation, since dispersion cannot be calculated.

Outcome measures

Outcome measures
Measure
Inhaled Carbon Monoxide
n=1 Participants
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
n=1 Participants
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Montreal Cognitive Assessment- MoCA-Blind
19 scores on a scale
Standard Deviation NA
Not calculable for a single participant
19 scores on a scale
Standard Deviation NA
Not calculable for a single participant

SECONDARY outcome

Timeframe: 3 months

The Hayling Sentence Completion Test assesses executive functioning (response initiation and inhibition), administered via telephone. With 30 sentence-completion items split into 2 sections (15 each). Sections: * 1: Response initiation (time to provide a contextually appropriate word). * 2: Response inhibition (time and error score for providing an unrelated word). Scores (response time and errors) from both sections are combined and converted to an age-adjusted standardized total score. Total combined standardized score ranges from 1-10: 1. Impaired 2. Abnormal 3. Poor 4. Low Average 5. Moderate Average 6. Average 7. High Average 8. Good 9. Superior 10. Very Superior Higher scores= Better executive functioning Lower scores= Greater impairment. A limited number of measurements prevents variance and dispersion analyses; therefore, we report available group data as "means" without standard deviation where dispersion cannot be calculated.

Outcome measures

Outcome measures
Measure
Inhaled Carbon Monoxide
n=2 Participants
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
n=1 Participants
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Hayling Sentence Completion Test
6.5 scores on a scale
Standard Deviation 0.71
4 scores on a scale
Standard Deviation NA
Not calculable for a single participant

SECONDARY outcome

Timeframe: 6 months

Population: Please note that one of the CO subjects was alive and well at 6 months but declined participation in the Hayling test.

The Hayling Sentence Completion Test assesses executive functioning (response initiation and inhibition), administered via telephone. With 30 sentence-completion items split into 2 sections (15 each). Sections: * 1: Response initiation (time to provide a contextually appropriate word). * 2: Response inhibition (time and error score for providing an unrelated word). Scores (response time and errors) from both sections are combined and converted to an age-adjusted standardized total score. Total combined standardized score ranges from 1-10: 1. Impaired 2. Abnormal 3. Poor 4. Low Average 5. Moderate Average 6. Average 7. High Average 8. Good 9. Superior 10. Very Superior Higher scores= Better executive functioning Lower scores= Greater impairment. A limited number of measurements prevents variance and dispersion analyses; therefore, we report available group data as "means" without standard deviation, since dispersion cannot be calculated.

Outcome measures

Outcome measures
Measure
Inhaled Carbon Monoxide
n=1 Participants
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
n=1 Participants
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Hayling Sentence Completion Test
7 scores on a scale
Standard Deviation NA
Not calculable for a single participant
5 scores on a scale
Standard Deviation NA
Not calculable for a single participant

OTHER_PRE_SPECIFIED outcome

Timeframe: Baseline and 3 days

Population: Percentage reduction pre-day 1 Vs. post-day 3 exposure for those subjects with 3 exposures.

Mitochondrial DNA (mtDNA) plasma levels will be measured on days 1-3 by quantitative PCR of human NADH dehydrogenase 1. Limited number of measurements prevents variance analyses; therefore we present the data from the subjects available in each group and report as "Mean" without standard deviation, since measures of dispersion cannot be calculated.

Outcome measures

Outcome measures
Measure
Inhaled Carbon Monoxide
n=1 Participants
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
n=1 Participants
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Change in Biomarkers of Mitochondrial Dysfunction
-78 Percentage drop in mitochondrial DNA
Standard Deviation NA
Not calculable for a single participant
-49 Percentage drop in mitochondrial DNA
Standard Deviation NA
Not calculable for a single participant

OTHER_PRE_SPECIFIED outcome

Timeframe: 5 days

Population: We present percent change over time from baseline to final measurement for a representative marker of inflammasome activation.

Plasma IL-18 levels will be measured on days 1-3 and day 5 by ELISA. We present the data from the subjects available in each group and report as "Mean" with standard deviation.

Outcome measures

Outcome measures
Measure
Inhaled Carbon Monoxide
n=2 Participants
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
n=2 Participants
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Change in Biomarkers of Inflammasome Activation
3.52 Percent change in IL-1B
Standard Deviation 3.14
-17.03 Percent change in IL-1B
Standard Deviation 15.70

OTHER_PRE_SPECIFIED outcome

Timeframe: 5 days

Population: Due to missing values we calculated percent change over time.

Plasma RIPK3 levels will be measured on days 1-3 and day 5 by ELISA. We present the data from the subjects available in each group and report as "Mean" with standard deviation.

Outcome measures

Outcome measures
Measure
Inhaled Carbon Monoxide
n=2 Participants
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
n=2 Participants
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Change in Biomarkers of Necroptosis
-46.60 Percent change in RIPK3 from baseline
Standard Deviation 27.65
12.30 Percent change in RIPK3 from baseline
Standard Deviation 12.63

OTHER_PRE_SPECIFIED outcome

Timeframe: 5 days

Population: We present percent change over time from baseline to final measurement for a representative marker of pro-resolving lipid mediators.

Lipid mediators (LM) and specialized pro-resolving mediators (SPMs) will be measured in plasma on days 1-3 and day 5 using liquid chromatography-tandem mass spectrometry (LC-MS-MS) based methods. We present the data from the subjects available in each group and report as "Mean" with standard deviation.

Outcome measures

Outcome measures
Measure
Inhaled Carbon Monoxide
n=2 Participants
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
n=2 Participants
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Plasma Lipid Mediators (LM) and Specialized Pro-resolving Mediators (SPMs)
-63.23 Percent change 14-HDHA
Standard Deviation 4.06
196.91 Percent change 14-HDHA
Standard Deviation 372.26

Adverse Events

Inhaled Carbon Monoxide

Serious events: 1 serious events
Other events: 0 other events
Deaths: 0 deaths

Medical Air

Serious events: 1 serious events
Other events: 0 other events
Deaths: 1 deaths

Serious adverse events

Serious adverse events
Measure
Inhaled Carbon Monoxide
n=2 participants at risk
Inhaled Carbon Monoxide at CFK equation-determined personalized dose (200-500 ppm to achieve a COHb level of 6-8%) for up to 90 minutes daily for 3 days.
Medical Air
n=2 participants at risk
Inhaled Medical Air for up to 90 minutes daily for 3 days.
Respiratory, thoracic and mediastinal disorders
Respiratory failure
50.0%
1/2 • Adverse events were assessed from enrollment until day 7. All-Cause Mortality was assessed up to 60 days
Daily follow-up of pre-specified clinical monitoring.
0.00%
0/2 • Adverse events were assessed from enrollment until day 7. All-Cause Mortality was assessed up to 60 days
Daily follow-up of pre-specified clinical monitoring.
Cardiac disorders
Atrial fibrilation
0.00%
0/2 • Adverse events were assessed from enrollment until day 7. All-Cause Mortality was assessed up to 60 days
Daily follow-up of pre-specified clinical monitoring.
50.0%
1/2 • Adverse events were assessed from enrollment until day 7. All-Cause Mortality was assessed up to 60 days
Daily follow-up of pre-specified clinical monitoring.
General disorders
Death NOS
0.00%
0/2 • Adverse events were assessed from enrollment until day 7. All-Cause Mortality was assessed up to 60 days
Daily follow-up of pre-specified clinical monitoring.
50.0%
1/2 • Adverse events were assessed from enrollment until day 7. All-Cause Mortality was assessed up to 60 days
Daily follow-up of pre-specified clinical monitoring.

Other adverse events

Adverse event data not reported

Additional Information

Rebecca Baron MD, Co-PI

Brigham and Women's Hospital

Phone: 6177326660

Results disclosure agreements

  • Principal investigator is a sponsor employee
  • Publication restrictions are in place