Tantangan dalam Menjaga Cerebral Perfusion Pressure (CPP) yang Aman pada Cedera Otak Traumatik

Cerebral perfusion pressure (CPP) is the net pressure gradient that drives oxygen delivery to cerebral tissue. It is the difference between the mean arterial pressure (MAP) and the intracranial pressure (ICP), CPP = MAP-CVP or CPP =MAP – ICP if ICP>CVP. Cerebral perfusion pressure must be maintained within narrow limits because too litle pressure could cause brain tissue become ischemic, and too much could raise intracranial pressure. The normal range lies between 60 and 80 mmHg, but these values can shift to the left or right depending on individual patient physiology. As CPP is a calculated measure, MAP and ICP must be measured simultaneously, most commonly by invasive means. When brain injury occurs, cerebral capillaries can become “leaky” or more permeable to water. In addition, cerebral blood vessels may dilate in respons to brain tissue injury, hypoxemia, hypercarbia, acidosis, or hypotension. If blood pressure becomes elevated, the increased CPP can lead to increased cerebral blood flow. The recommended goal of CPP per the Brain Trauma Foundation (BTF) guideline is 50-70 mmHg. Targeting high CPP >70 mmHg has not been shown to be beneficial in patient with traumatic brain injury and is associated with an increased risk of acute respiratory distress syndrome (ARDS).