Marín-Caballos, Antonio J.Murillo-Cabezas, FranciscoCayuela-Domínguez, AurelioDomínguez-Roldán, Jose M.Rincón-Ferrari, M. DoloresValencia-Anguita, JulioFlores-Cordero, Juan M.Muñoz-Sánchez, M Angeles2014-07-242014-07-242005-10-14Marín-Caballos AJ, Murillo-Cabezas F, Cayuela-Domínguez A, Domínguez-Roldán JM, Rincón-Ferrari MD, Valencia-Anguita J, et al. Cerebral perfusion pressure and risk of brain hypoxia in severe head injury: a prospective observational study. Crit Care. 2005; 9(6):R670-6http://hdl.handle.net/10668/1690Evaluation Studies; Journal Article;INTRODUCTION Higher and lower cerebral perfusion pressure (CPP) thresholds have been proposed to improve brain tissue oxygen pressure (PtiO2) and outcome. We study the distribution of hypoxic PtiO2 samples at different CPP thresholds, using prospective multimodality monitoring in patients with severe traumatic brain injury. METHODS This is a prospective observational study of 22 severely head injured patients admitted to a neurosurgical critical care unit from whom multimodality data was collected during standard management directed at improving intracranial pressure, CPP and PtiO2. Local PtiO2 was continuously measured in uninjured areas and snapshot samples were collected hourly and analyzed in relation to simultaneous CPP. Other variables that influence tissue oxygen availability, mainly arterial oxygen saturation, end tidal carbon dioxide, body temperature and effective hemoglobin, were also monitored to keep them stable in order to avoid non-ischemic hypoxia. RESULTS Our main results indicate that half of PtiO2 samples were at risk of hypoxia (defined by a PtiO2 equal to or less than 15 mmHg) when CPP was below 60 mmHg, and that this percentage decreased to 25% and 10% when CPP was between 60 and 70 mmHg and above 70 mmHg, respectively (p < 0.01). CONCLUSION Our study indicates that the risk of brain tissue hypoxia in severely head injured patients could be really high when CPP is below the normally recommended threshold of 60 mmHg, is still elevated when CPP is slightly over it, but decreases at CPP values above it.enPresión SanguíneaTraumatismos CraneocerebralesCuidados CríticosHipoxia EncefálicaTelencéfaloMedical Subject Headings::Analytical, Diagnostic and Therapeutic Techniques and Equipment::Diagnosis::Diagnostic Techniques and Procedures::Physical Examination::Vital Signs::Blood PressureMedical Subject Headings::Diseases::Nervous System Diseases::Trauma, Nervous System::Craniocerebral TraumaMedical Subject Headings::Analytical, Diagnostic and Therapeutic Techniques and Equipment::Therapeutics::Patient Care::Critical CareMedical Subject Headings::Diseases::Pathological Conditions, Signs and Symptoms::Pathologic Processes::Disease Attributes::Critical IllnessMedical Subject Headings::Check Tags::FemaleMedical Subject Headings::Organisms::Eukaryota::Animals::Chordata::Vertebrates::Mammals::Primates::Haplorhini::Catarrhini::Hominidae::HumansMedical Subject Headings::Diseases::Nervous System Diseases::Central Nervous System Diseases::Brain Diseases::Hypoxia, BrainMedical Subject Headings::Check Tags::MaleMedical Subject Headings::Chemicals and Drugs::Inorganic Chemicals::Elements::Chalcogens::OxygenMedical Subject Headings::Analytical, Diagnostic and Therapeutic Techniques and Equipment::Investigative Techniques::Epidemiologic Methods::Epidemiologic Study Characteristics as Topic::Epidemiologic Studies::Cohort Studies::Longitudinal Studies::Prospective StudiesMedical Subject Headings::Analytical, Diagnostic and Therapeutic Techniques and Equipment::Investigative Techniques::Weights and Measures::Reference ValuesMedical Subject Headings::Analytical, Diagnostic and Therapeutic Techniques and Equipment::Investigative Techniques::Epidemiologic Methods::Statistics as Topic::Probability::Risk::Risk AssessmentMedical Subject Headings::Analytical, Diagnostic and Therapeutic Techniques and Equipment::Investigative Techniques::Epidemiologic Methods::Statistics as Topic::Probability::Risk::Risk FactorsMedical Subject Headings::Anatomy::Nervous System::Central Nervous System::Brain::Prosencephalon::TelencephalonMedical Subject Headings::Named Groups::Persons::Age Groups::Adultresearch article16356218open access10.1186/cc38221466-609XPMC1414023