Avaliação do transporte de oxigenio e da concentração do 2,3-DPG em pacientes com traumatismo craniencefalico grave submetidos ao controle da hipertensão intracraniana por um protocolo de ventilização otimizada

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

Optimized ventilation is a therapeutic modality for severe traumatic brain injury. Essentially, alveolar ventilation is adjusted to optimal levels in order to keep intracranial pressure below 20mmHg and cerebral oxygen extraction (CEO2) within recommended limits (24 to 42%). Determination of CEO2 is based on blood oxygen saturation. Hemoglobin oxygen saturation is measured directly by blood oxymetry. Alternatively, hemoglobin saturation may be calculated from the oxygen partial pressure of blood. In this case, 2,3-DPG/Hct is not considered. In critical patients there are several causes that may alter 2,3-DPG in red blood cells. Respiratory alkalosis induced by hyperventilation has been reported to increase 2,3-DPG/Hct. Based on this physiologic response, the objective of this investigation was to evidence a progressive increase in 2,3-DPG/Hct in association with hyperventilation and to assess their repercussion in the hemoglobin saturation and in the CEO2. However, a progressive increase in 2,3-DP/Hct did not happen. This apparent inconsistency was attributed to intermittency of hyperventilation, to blood transfusions and to hypophosphatemia. Nevertheless, individual variations of 2,3-DPG/Hct correlated with arterial pH and PCO2. Significant individual differences between CEO2m and CEO2c (?CEO2) were found. The concentration of 2,3-DPG/Hct exhibited a significant statistical correlation with ?CEO2. In conclusion, as 2,3-DPG/Hct interferes with the accuracy of calculated CEO2, this variable must always be derived from blood oximetry saturation

ASSUNTO(S)

hemoglobina traumatismos cerebrais traumatismo da cabeça oxigenio - transporte fisiologico

ACESSO AO ARTIGO

Documentos Relacionados