Multimodal neuromonitoring-related complications in patients with severe acute brain injury: a retrospective cohort study

Abstract Background Invasive multimodal neuromonitoring (MMNM) is standard of care in many neuro-intensive care units for patients with severe acute brain injury. MMNM is used for monitoring of early signs of secondary brain injury. Still, the safety of this approach is only partly clarified. This study aimed to investigate the prevalence and types of MMNM-related complications. Methods For this single-centre retrospective study, we included all patients admitted to the Neurointensive Care Unit at Rigshospitalet from March 2017 to December 2023, who were monitored using MMNM probes in the brain, i.e. monitoring of intracranial pressure (ICP) in combination with brain tissue oxygen tension (PbtO 2 ) and/or cerebral microdialysis (CMD). Medical records and computed tomography (CT) or magnetic resonance imaging (MRI) of the head were reviewed for MMNM-related complications and functional outcome at 6 months after ictus. Results A total of 223 patients with severe acute brain injury underwent monitoring with MMNM. Imaging was done after insertion in 196 patients (88%) of all who received MMNM. In these, haemorrhage related to the insertion was observed in 25 patients (13%), suboptimal location in 70 (36%), bone fragments in 25 (13%), and pneumocephalus in 71 (36%); none of these necessitated intervention. Among the entire cohort of 223 patients, infection related to MMNM occurred in one patient (0.4%); malfunction was reported by clinicians in 64 patients (29%) and verified in 26 (12%). After MMNM removal, 162 patients (73%) had a CT or MRI scan, of whom 11 patients (6.8%) had a new parenchymal haemorrhage; one patient (0.4%) underwent surgical haematoma evacuation. Six months functional outcome did not differ between patients with and those without MMNM-related complications. Conclusion In this retrospective study, a high number of MMNM-related complications was found, of which the vast majority did not cause clinical concern and did not affect patient treatment or outcomes.