Is CPP greater than 70 mmHg necessary?
Some recent evidence suggests that CPP values greater than 70 mmHg do not necessarily achieve the goal of avoiding hypoperfusion and hypoxia. Steiner et al (17) evaluated the response of CBF in the pericontusional tissue at 70 and 90 mmHg of CPP. Higher CPP caused only a modest increase in CBF, which does not justify pharmacological elevation of CPP to greater than 70 mmHg. In a study of 18 patients monitored by noninvasive cerebral oximeter, despite demonstration of a CPP greater than 70 mmHg for 90% of the study period, there was a 16% detectable incidence of cerebral hypoxia, supporting the idea that cerebral hypoxia occurs despite what is considered adequate CPP (18).
