Table 3.
Characteristics of patients with a falsely pessimistic EEG-based prediction
| Study cohort (except the 18 false-positive patients) (n = 827) | False positives with highly malignant EEG (n = 18) | |
|---|---|---|
| Age–years (mean ± std dev) | 66 ± 13 | 61.8 ± 9.5 |
| Male gender—no. (%) | 664 (80.3) | 14 (77.8) |
| CA-related variables | ||
| Bystander witnessed CA—no. (%) | 656 (79.3) | 17 (94.4) |
| Shockablea first rhythm—no. (%) | 574 (69.4) | 13 (72.2) |
| Time to ROSCb—minutes, median (IQR) | 28 (19–41) | 26 (16–36) |
| ICU-related variables | ||
| TTM 33 °C—no. (%) | 429 (51.9) | 13 (72.2) |
| Time to EEG from CA—hours, median (IQR) | 72 (52.8–93.6) | 72 (50.4–96) |
| Reactive EEG background (tested in 821 patients) | 265/805 (32.9) | 8/16 (50) |
| Clinical seizuresc—no. (%) | 337 (40.7) | 2 (11) |
| Ongoing sedation at the EEG time point—no. (%) | 392/586 (66.9) | 10/14 (71.4) |
| Propofol in the first 72 h,—no. (%) | 715/806 (88.7) | 15/17 (88.2) |
| Propofol cumulative dose up to 72 h,—mg, median (IQR) | 9653 (5113–14630) | 9499 (4202–12074) |
| Midazolam in the first 72 h,—no. (%) | 384/807 (47.6) | 11/17 (64.7) |
| Midazolam cumulative dose up to 72 h,—mg, median (IQR) | 150 (27–340) | 386 (16–648) |
| Prognostication performed—no. (%) | 597 (72.2) | 14 (77.8) |
| Poor prognosis likely at the time of prognostication—no. (%)d | 243/597 (40.7) | 1/14 (7.1) |
| Number of modalities used for prognosticatione—median (IQR) | 3 (3–4) | 3 (2–3.25) |
| FOUR motor score on day 4 (day of prognostication)—median (IQR) | 0 (0–2) | 0 (0–2) |
| Time to awakening—hours, median (IQR) | 109 (67–169) | 144 (117–261) |
| WLST performed—no. (%) | 412 (49.8) | 0 (0) |
| Outcome | ||
| Good neurological outcome (mRS 0–3)—no. (%) | 248 (30) | 18 (100) |
Baseline characteristics of patients with a falsely pessimistic EEG-based prediction (n = 18) compared to the remaining study cohort (n = 827)
CA cardiac arrest, mRS modified Rankin scale, NSE neuron-specific enolase, ROSC return of spontaneous circulation, SSEP somatosensory-evoked potentials, TTM target temperature management, WLST withdrawal of life-sustaining therapy
aVentricular fibrillation, pulseless ventricular tachycardia or unknown rhythm responsive to shock
bFor unwitnessed arrests, time intervals were calculated from the emergency call to ROSC
cMyoclonic seizures or tonic/clonic seizures
dPresence of at least two concordant predictors of poor outcome at the time point of prognostication (96 h): both pupillary and corneal reflexes absent at 96 h after CA or later, an early (within 48 h) status myoclonus, an unreactive highly malignant EEG pattern, brain CT with signs of global ischaemic injury, serial levels of NSE consistently higher than locally established levels, N20 SSEP wave bilaterally absent more than 48 h after CA, in patients without confounding factors and without motor response or with a stereotypic extensor response to bilateral central and peripheral painful stimulation at ≥ 96 h after CA. In comatose patients who did not fulfil the trial criteria of poor outcome, active care was continued and patients were re-evaluated daily
ePrognostic modalities: pupillary and corneal reflexes; status myoclonus; EEG; CT or MRI of the brain; neuron-specific enolase in serum; median nerve somatosensory-evoked potentials