Analysis of extracellular brain chemistry during percutaneous dilational tracheostomy: A retrospective study of 19 patients

Objective: The purpose of this study was to analyze changes in brain tissue chemistry around percutaneous dilational tracheostomy (PDT) in patients with acute brain injury (ABI) in a retrospective single-center analysis. Patients and methods: We included 19 patients who had continuous monitoring of brain tissue chemistry and intracranial pressure (ICP) during a 20 h period before and after PDT. Different microdialysis parameters (lactate, pyruvate, lactate pyruvate ratio (LPR), glycerol and glutamate) and values of ICP, cerebral perfusion pressure (CPP) and brain tissue oxygenation (PBrO2) were recorded per hour. Mean values were compared between a 10 h period before PDT (prePDT) and after PDT (postPDT). Results: Mean values of cerebral lactate, pyruvate, LPR, glycerol and glutamate did not differ significantly between prePDT and postPDT. In addition, the rate of patients, which exceeded the known threshold was similar between prePDT and postPDT. Only one patient showed a strong increase of cerebral glycerol during the postPDT period, but analysis of subcutaneous glycerol could exclude an intracerebral event. ICP, CPP and PBrO2 did not exhibit significant changes. Conclusions: We could exclude the occurrence of cerebral metabolic crisis and the excess release of cerebral glutamate and glycerol in a series of 19 patients. Our results support the safety of PDT in patients with ABI.