How I manage intracranial hypertension

Why and when to manage intracranial hypertensionThe detrimental effects of intracranial hypertension (HICP, high intracranial pressure) are well documented [1,2].HICP can cause secondary brain injury and death, and therefore, intracranial pressure (ICP) elevations should be aggressively treated.HICP has been classically defined as an ICP > 20 mmHg, and this threshold has been considered the trigger for treatment [3].Recent BTF guidelines have moved this threshold to 22 mmHg [4], grounded on a single-centre, retrospective study.This modification is trivial [5].As for many other treatment options in intensive care, a single threshold is debatable.In fact, recent evidence suggests that not a single value but the time spent over the threshold and its intensity, the so-called ICP dose, is more important [6].Moreover, Guiza demonstrated that not only higher values but also prolonged exposure to values below the classical threshold are associated with negative outcomes [7].In addition, if cerebral perfusion pressure (CPP, i.e.MAP-ICP) is critically low (< 50 mmHg), ICP is no longer a predictor for poor outcome and lower ICP values might be barely tolerated.On the contrary, ICP insults in the range 18-23 mmHg can be tolerated for a longer duration at higher CPPs.In my practice, the ICP alarm is set at 20 mmHg and low CPP alarm at 55 mmHg.This is a warning signal for nurses at the bedside.Before starting any treatments for high ICP, I consider both the intensity and duration of HICP.I am flexible with thresholds putting them in the clinical contest, considering also CPP.Short-lasting, low-intensity episodes (low ICP dose with normal CPP) are observed and not treated.On the contrary, higher ICP doses, progressively rising trends, or/ and HICP impacting CPP require prompt treatment.