Fig. 3

Lung ultrasound–Brain ultrasound (LUS–BUS) combined respiratory and neurological monitoring in patients with traumatic brain injury (TBI) and acute respiratory distress syndrome (ARDS). A four-tiered approach is suggested, in order to decide the best ventilatory strategy and simultaneously monitor the effects on intracranial pressure (ICP) and on cerebrovascular dynamics. The goal is to set the ventilation consistently with a lung-protective strategy without negatively affecting the injured brain. Step 1—scanning of ventral and dorsal chest areas allows to differentiate ARDS with focal/patchy morphology (with less recruitment potential and greater risk of anterior lung overdistention) from ARDS with diffuse, more homogenous, morphology (amenable to successful recruitment at higher PEEP levels). Step 2—once this has been established, the kind of recruitment maneuver suitable for the detected ARDS morphology is preceded by BUS. The detection of signs of intracranial hypertension allows the preemptive institution of medical ICP-directed treatment to reduce the negative impact of the ventilatory maneuvers on the brain. Step 3—the recruiting maneuver is performed [under the guide of driving pressure (ΔP) and static respiratory system compliance (C_RS), Volumetric Capnometry, SpO₂] while monitoring changes in lung aeration (LUS) and signs of their potential negative impact on ICP and cerebrovascular dynamics and (BUS). Step 4—the final effect of the recruitment maneuver and the chosen PEEP is finally assessed, both in terms of gas exchanges, lung mechanics, and of net effect on the ICP and cerebrovascular dynamics. Should the ventilation target not be reachable nor compatible with brain protection, other respiratory support strategies/ICP treatments should be considered. ARDS acute respiratory distress syndrome, LUS lung ultrasound, BUS brain ultrasound, PEEP positive end expiratory pressure, PI middle cerebral artery pulsatility index, V_d middle cerebral artery diastolic arterial flow velocity, FV flow velocity; ONSD optic nerve sheath diameter, MAP mean systemic arterial pressure, ICP intracranial pressure, BGA blood gas analysis, TBI traumatic brain injury, ECCOR extracorporeal CO₂ removal, vvECMO veno-venous extracorporeal membrane oxygenation, EEG electroencephalography, C_RS respiratory system compliance, ΔP driving pressure, Cap_Vol volumetric capnometry, SpO₂ arterial oxygen saturation