Hyperbaric Oxygen for Carbon Monoxide Induced Chronic Encephalopathy (HACMICE)

In some patients, a few days or weeks after recovery from carbon monoxide poisoning, new symptoms develop. These can affect mood, ability to think or remember clearly, and movements. Some people develop movement problems that are similar to Parkinson's disease. This damage to brain tissue is called "encephalopathy," and this study will look at the effect of pressurized oxygen therapy on long term, or chronic, encephalopathy.

Study Overview

• Status: Withdrawn
• Conditions: Carbon Monoxide Poisoning; Chronic Encephalopathy
• Intervention / Treatment: Device: hyperbaric oxygen and sham hyperbaric oxygen

Detailed Description

Carbon monoxide (CO) poisoning is a leading cause of unintentional poisoning deaths in the United States. After a period of apparent recovery, survivors of acute CO-poisoning can develop a potentially permanent neurologic deterioration (DNS). DNS is a rare, poorly known encephalopathy with a 25-50% prevalence among severely poisoned CO-poisoned patients. Its symptoms and signs range from subtle abnormalities to severe dementia, Parkinsonism, gait disturbances, mutism, and incontinence. Recovery from delayed neuropsychiatric syndrome occurs in 50-75% of patients within 1 year. However, this leaves 25-50% permanently impaired.

Hyperbaric oxygen therapy (HBO2) is useful after acute poisoning to reduce the chance of developing DNS. However, appropriate therapy for DNS is widely debated; particularly, the role of hyperbaric oxygen therapy (HBO2) after DNS has developed is controversial. This study proposes to ascertain whether hyperbaric oxygen is efficacious in the treatment of chronic DNS brain injury from carbon monoxide (CO) poisoning. Ten participants suffering from DNS for longer than one year will be recruited to the study, which will be prospective, blinded, sham-controlled and crossover in design. Participants will be divided into two groups of five. One group will receive 40 HBO2 treatments [100% oxygen at twice normal air pressure (2 ATA)] followed by 40 sham HBO2 treatments [air at near normal pressure (1.2 ATA)]. Treatments will be done once daily for 2 hours, Monday through Friday. Neurological and psychologic assessments will be done prior to starting treatments, after each group of 40 treatments. The second group will be treated similarly except that they will receive sham treatments in the first and oxygen treatments second. In this manner, all participants will act as both experimental and control subject and will receive treatment which we believe is therapeutic.

• Study Type: Interventional
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Nebraska
    • Omaha, Nebraska, United States, 68198
      • UNMC

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 10 years to 90 years (Child, Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• CO induced neurological or cognitive sequelae assessed as at least mild (e.g. UPDRS part 3 (motor)>15).
• chronicity- signs or symptoms present for greater than one year after exposure.

Exclusion Criteria:

• age >90 or less than 10 years
• other morbidities which may contribute to chronic neurocognitive deficits (such as traumatic brain injury, poisoning by other toxins, other neurodegenerative diseases)
• pregnancy (if a subject becomes pregnant she will be removed from the study)
• routine contraindications to hyperbaric oxygen

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Sham Comparator: sham1st; 40 sham HBO2 treatments (air at near normal pressure (1.2 ATA)). Treatments will be done once daily for 2 hours, Monday through Friday. The second block will be treated similarly except that they will receive sham treatments in the first block and oxygen treatments in the second block.	Device: hyperbaric oxygen and sham hyperbaric oxygen; see arm descriptions
Active Comparator: sham second; iii. We will divide the subjects into two groups of five. One group will receive 40 Hyperbaric Oxygen (HBO2) treatments (100% oxygen at twice normal air pressure (2 ATA)) followed by 40 sham HBO2 treatments (air at near normal pressure (1.2 ATA)). Treatments will be done once daily for 2 hours, Monday through Friday. The second block will be treated similarly except that they will receive sham treatments in the first block and oxygen treatments in the second block. iv. Neurological and psychologic assessments will be done prior to starting treatments, after the first block of 40 and again after the second block of 40.	Device: hyperbaric oxygen and sham hyperbaric oxygen; see arm descriptions

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Short Form (36) Health Survey	is a 36-item, patient-reported survey of patient health	4 months (after 80 treatments)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Updrs part 3 (motor function)	Unified Parkinson Disease Rating Scale	0, 2 and 4 months: (prior to study, after 40 treatments and 80 treatments)
BARS- Brief Ataxia Rating Scale	an assessment of ataxia, 30 point scale with 0 being normal	0, 2 and 4 months: (prior to study, after 40 treatments and 80 treatments)
Fahn-Marsden Dystonia Rating Scale	an assessment of dystonia, 120 point scale with 0 being normal	0, 2 and 4 months: (prior to study, after 40 treatments and 80 treatments)
Physician assessment	an assessment of global function, this is a verbal description not a scale	prior to study, after 40 treatments and 80 treatments (0, 2 and 4 months)
The Montreal Cognitive Assessment	a brief cognitive screening tool for Mild Cognitive Impairment	0, 2 and 4 months: (prior to study, after 40 treatments and 80 treatments)
Short Form (36) Health Survey	is a 36-item, patient-reported survey of patient health	0, 2 and 4 months: (prior to study, after 40 treatments and 80 treatments)

Collaborators and Investigators

• Sponsor: University of Nebraska
• Investigators: Principal Investigator: Jeffrey Cooper, MD, University of Nebraska

Study record dates

Study Major Dates

• Study Start (Actual): June 6, 2023
• Primary Completion (Actual): June 6, 2023
• Study Completion (Actual): June 6, 2023

Study Registration Dates

• First Submitted: July 26, 2019
• First Submitted That Met QC Criteria: October 4, 2019
• First Posted (Actual): October 8, 2019

Study Record Updates

• Last Update Posted (Actual): September 3, 2024
• Last Update Submitted That Met QC Criteria: August 29, 2024
• Last Verified: August 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Chemically-Induced Disorders; Pathologic Processes; Central Nervous System Diseases; Nervous System Diseases; Disease Attributes; Gas Poisoning; Chronic Disease; Poisoning; Brain Diseases; Carbon Monoxide Poisoning; Brain Damage, Chronic
• Other Study ID Numbers: 0225-18-FB

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: No