Clinical trial NCT04475263: Cognitive and Blood Biomarker Assessment After CO Exposure
Official title: Cognitive, Behavioural and Blood Biomarker Assessment After Carbon Monoxide (CO) Exposure
Study type: OBSERVATIONAL
Overall status: UNKNOWN
Conditions: Carbon Monoxide Poisoning
Lead sponsor: St George's, University of London
Sponsor class: OTHER
Collaborators: name: University College, London
First posted: 2020-07-17
Enrollment: 50
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: CASE_ONLY
Time perspective: CROSS_SECTIONAL
Sampling method: NON_PROBABILITY_SAMPLE
Study population: 50 individuals with confirmed evidence of CO exposure will be recruited.

Brief summary: Carbon monoxide (CO) is reported to cause around 30 deaths, 200 admissions and 4000 presentations to Emergency Departments each year in the UK. In the longer term, CO poisoning is recognised to cause persistent neurological problems (including impairments of thinking and behavioural changes), which can develop days to weeks after the initial exposure. However, the incidence of these long-term sequelae is unknown. In addition, there is evidence of long-lasting inflammatory changes in the brain and on-going brain cell injury, although how long this persists is also unknown.

Initial assessments of CO exposure can be unreliable if blood tests are not carried out within a relatively short period after the exposure and other biomarkers (such as imaging) are insensitive to detecting previous CO exposure. Certain proteins that are found in brain cells can be detected in the blood of individuals following brain injury and brain cell death. These proteins have been found to be raised in the acute period after minor head injury, persistently raised in patients with a traumatic brain injury and evidence of on going neurodegeneration (i.e. on going brain cell death) and in patients with various types of dementia.

The investigators will assess the presence of these proteins in the blood of 50 participants with proven CO exposure in the sub-acute to chronic timescale (2 weeks to 2 years). This has not been done before and will allow assessment of the presence of on going brain injury in these participants. The investigators will also assess cognitive (e.g. memory, attention and speed of thinking) and behavioural impairments in these participants to help characterise the common impairments suffered following CO exposure and relate these to evidence of persistent brain injury and severity of CO exposure.


Eligibility criteria: Inclusion Criteria:

Individuals identified as having confirmed exposure to CO between 2 weeks to 2 years at time of assessment. CO exposure determined by either;

* documented COHb levels above 1.6% in non-smokers and above 6.3% in smokers.
* or, individuals with evidence of being exposed to raised levels of CO and symptoms

Exclusion Criteria:

* age \<18 years
* actual or suspected smoke inhalation
* significant neurological or psychiatric illness prior to CO exposure
* inability to provide consent

Primary outcomes:
measure: Blood biomarker level of neurofilament light in participants with proven CO exposure.
timeFrame: 18 months
Secondary outcomes:
measure: Blood biomarker level of tau in participants with proven CO exposure.
timeFrame: 18 months
measure: Blood biomarker level of glial fibrillary acidic protein in participants with proven CO exposure.
timeFrame: 18 months
measure: Behavioural questionnaire: depression (Patient Health Questionnaire - part 9)
timeFrame: 18 months
measure: Behavioural questionnaire: anxiety (Generalised Anxiety Disorder Questionnaire - GAD7)
timeFrame: 18 months
measure: Behavioural questionnaire: post-traumatic stress symptoms (Impact of Events Scale)
timeFrame: 18 months
measure: Behavioural questionnaire: Attentional behaviour (Rating Scale of Attentional Behaviour)
timeFrame: 18 months
measure: Behavioural questionnaire: fatigue (Visual Analogue Scale of Fatigue)
timeFrame: 18 months
measure: Behavioural questionnaire: Quality of life (The Short Form (36) Health Survey)
timeFrame: 18 months
measure: Behavioural questionnaire: return to work/social activities (Work and Social Adjustment Scale)
timeFrame: 18 months
measure: Cognitive assessment
timeFrame: 18 months
Other outcomes:
Locations:
Study officials:
affiliation: St. George's Hospital, London
name: Peter O Jenkins, PhD
role: PRINCIPAL_INVESTIGATOR
References: