Ch 28 (s28.7, s28.13); Ch 25; Ch 54
The optimal pressure for an individual brain ranged from 55 to 110 mmHg, so there is no population mean arterial pressure target that serves this group — a protocol targeting 65 mmHg for everyone is targeting the wrong number in roughly half of these patients, in an unknowable direction. And day 1 is the vulnerable day: impairment was worse and time outside limits five times greater than on day 2. Read alongside Chapter 25's porcine finding that a carotid flow deficit persisted after mean arterial pressure was restored: restoring the pressure number does not demonstrate that cerebral flow has been restored.
Post-cannulation day 1 versus day 2; venoarterial versus venovenous; modified Rankin Scale 0 to 3 versus 4 to 6 at 3 and 6 months
DOI 10.1007/s12028-023-01932-w
Continuous cerebral oximetry index monitoring, a moving correlation between mean arterial pressure and slow waves of regional cerebral oxygen saturation from near-infrared spectroscopy, used to derive an optimal mean arterial pressure and individual limits of autoregulation
Fifteen patients; feasibility was the stated primary aim and feasibility is what was demonstrated. The outcome comparison is a narrow separation between two very high numbers, which says as much about how poorly pressure was controlled in everyone as about the difference between outcome groups. No interventional study has tested whether targeting an individualised pressure changes anything. An earlier preprint carries DOI 10.21203/rs.3.rs-3300834/v1.
Mean index higher (worse autoregulation) on day 1 than day 2 (0.2 versus 0.09, p under 0.01) and higher on venoarterial than venovenous support (0.12 versus 0.06, p=0.04). Median optimal mean arterial pressure for the cohort was highly variable, ranging 55 to 110 mmHg. Time with observed pressure outside the limits of autoregulation was higher on day 1 than day 2 (18.2 versus 3.3 percent, p under 0.01). Patients with good functional outcome spent less time outside optimal pressure than those with poor outcome (74 versus 82 percent, p=0.01).
15 adult ECMO patients at a single centre (median age 57, IQR 47 to 69) — 11 venoarterial and 4 venovenous — yielding 150 autoregulation measurements