Fig. 2

Invasive and non-invasive intracranial pressure monitoring, respectively, through ICP Bolt and through brain ultrasound (BUS, optic nerve sheath diameter and cerebrovascular Doppler sampling) in a patient with traumatic brain injury and ARDS. A 26-year-old lady was admitted to the intensive care unit after a road traffic accident. She presented with severe traumatic brain injury (TBI) and chest trauma with lung contusions. She was monitored with invasive ICP, intubated and mechanically ventilated. On day 2, she developed hypoxic respiratory failure with bilateral atelectasia. We therefore performed recruitment maneuvers with ABP, CPP, and ICP monitoring and concomitant ONSD and TCD measurements (venous TCD on the SS and arterious TCD on the MCA). Recordings and scanning were performed at baseline (left panels) and during a recruitment maneuver and subsequent increase in PEEP level (right panels). Initially, ICP was below 20 mmHg (mean ONSD = 5.2), with PEEP = 8, with stable arterial blood pressure (ABP) and cerebral perfusion pressure (CPP). After recruitment maneuvers and setting PEEP at 16, ICP spiked up > 20 mmHg, with reflex mean systemic arterial blood pressure (ABP) and cerebral perfusion pressure (CPP) increase. BUS showed consistent increase in middle cerebral artery (MCA) pulsatility index (decrease in diastolic flow, increase in systolic flow), reduction in straight sinus (SS) flow, and increase in optic nerve sheath diameter (ONSD = 7 mm). PaCO₂ remained constant during the procedure and the patients experienced no hypotension nor cardiac output decrease. We therefore reduced PEEP levels and noticed that ICP immediately decreased as well as PI, ONSD and the venous flow on the straight sinus. MCA middle cerebral artery, SS straight sinus, ONSD optic nerve sheath diameter, ABP mean systemic arterial blood pressure, ICP intracranial pressure, CPP cerebral perfusion pressure