Hyperbaric oxygen therapy ameliorates acute brain injury after porcine intracerebral hemorrhage at high altitude

Hai-tao Zhu, Chen Bian, Ji-chao Yuan, Xiao-jun Liao, Wei Liu, Gang Zhu, Hua Feng, Jiang-kai Lin

Intracerebral hemorrhage (ICH) at high altitude is not well understood to date. This study investigates the effects of high altitude on ICH and examines the acute neuroprotection of hyperbaric oxygen (HBO) therapy against high-altitude ICH. Minipigs were placed in the hypobaric chamber for 72 h before operation. ICH was induced by infusion of autologous arterial blood (3 ml) into the right basal ganglia. High-altitude ICH animals received hyperbaric oxygen therapy (2.5 ATA, 60 min) 0.5 h after ICH. The animals from each group were monitored continuously for blood gas, blood glucose, brain tissue oxygen partial pressure (PbtO2) and microdialysis products including glucose, lactate, pyruvate and glutamate in perihematomal tissue from 3 h to 12 h post-ICH. High-altitude ICH animals showed significantly lower PbtO2, higher lactate/pyruvate ratio (LPR) and glutamate levels than low-altitude ICH animals. More severe neurological deficits, brain edema and neuronal damage were also observed in high-altitude ICH. After HBO therapy, PbtO2 was significantly increased and LPR and glutamate levels were significantly decreased. Brain edema, neurological deficits and neuronal damage were also ameliorated. The data suggested more serious disturbance of tissue oxygenation and cerebral metabolism in the acute stage after ICH at high altitude. Early HBO treatment reduced acute brain injury, perhaps through a mechanism involving the amelioration of the derangement of cerebral oxygenation and metabolism following high-altitude ICH.