Reoxygenation After Cardiac Arrest II (REOX II Study)

Specific Aim 1: Test if initiation of the rapid FiO2 optimization protocol following ROSC from cardiac arrest is associated with the degree of in vivo oxidative stress during the post-resuscitation phase of therapy.

Approach: We will conduct a multicenter interventional study (FiO2 optimization protocol) of adult patients resuscitated from cardiac arrest. We will record data pertaining to oxygenation parameters and other factors and measure biomarkers of oxidative stress [isoprostanes (IsoPs) and isofurans (IsoFs)] in the plasma at 0 and 6 hours after ROSC using gas chromatography negative ion chemical ionization mass spectrometry. We will compare plasma IsoPs/IsoFs at each time point between subjects enrolled in REOX II (i.e. receive the study intervention, rapid FiO2 optimization) and REOX I (i.e. do not receive the study intervention) using t-test or Mann-Whitney U as appropriate with corrections for multiple comparisons.

Specific Aim 2: Test if initiation of the rapid FiO2 optimization protocol following ROSC from cardiac arrest is associated with a decrease in neurological disability at hospital discharge.

Approach: In the study described above, we will determine the Modified Rankin Scale (mRS) at hospital discharge. We will compare proportions of good neurological outcome [defined as a mRS ≤ 3] between subjects enrolled in REOX II (i.e. receive the study intervention, rapid FiO2 optimization) vs. those enrolled in REOX I (i.e. do not receive the study intervention), using binomial test.

Specific Aim 3: Test if initiation of the rapid FiO2 optimization protocol following ROSC from cardiac arrest is associated with neuropsychological outcomes among survivors at 180 days.

Approach: In the study described above, we will assess neuropsychological outcome among survivors at 180 days. Neuropsychological testing will use validated instruments across five cognitive domains (attention, Wechsler Adult Intelligence Scale-IV-digit span; (2) reasoning, Wechsler Adult Intelligence Scale-IV-similarities; (3) immediate and delayed memory, Wechsler Memory Scale-III-logical memory I and II; (4) verbal fluency, Controlled Oral Word Association Test; and (5) executive functioning, Hayling Sentence Completion Test). Among survivors, we will compare the 180-day neuropsychological measures (composite z-scores for each cognitive domain) between the same two groups using t-test or Mann-Whitney U as appropriate with corrections for multiple comparisons. We will also compare the proportions of patients able to return to work between the two groups using binomial test

Inclusion criteria

• Age >17 years
• Cardiac arrest
• Return of spontaneous circulation
• Not following commands immediately after ROSC
• Endotracheal intubation
• Clinician intent to treat with therapeutic hypothermia (or absence of clinician intent to withhold therapeutic hypothermia)

Exclusion criteria

• Presumed etiology of arrest is trauma
• Presumed etiology of arrest is hemorrhage
• Presumed etiology of arrest is sepsis
• Permanent resident of nursing home or other long-term care facility
• Any other condition, that in the opinion of the investigator, would preclude the subject from being a suitable candidate, e.g. end stage chronic illness with no reasonable expectation of survival to hospital discharge