Effect of hyperoxia on cerebral blood flow velocity and regional oxygen saturation in patients operated upon for severe traumatic brain injury – the influence of cerebral blood flow autoregulation

• Published in: World neurosurgery
• Main Authors: Sahoo, Sarasa, MD, Sheshadri, Veena, MD, Sriganesh, Kamath, MD DM, Madhsudana Reddy, K.R., MD, Radhakrishnan, M., MD DM, Umamaheswara Rao, G.S., MD
• Format: Journal Article
• Language: English
• Published: 2016
• Subjects: Neurosurgery; SjVO2; HR; Transient Hyperemic Response Ratio; Mean Velocity; Middle Cerebral Artery; Near-infrared spectroscopy; rSO2; Inspired oxygen concentration; THRR; Glasgow Coma Scale; Neurointensive Care Unit; Systolic Velocity; NIRS; TBI; traumatic brain injury; Glasgow Outcome Scale; MV; Arterial Blood Gas; rM-ANOVA; TCD; BTF; CAR; Hyperoxia; cerebral blood flow; MAP; TCD FV; cerebral oxygenation; CMRO2; ABG; CBF; FiO2; Brain Trauma Foundation; NICU; Jugular Venous Oxygen Saturation; Vd; Vs; Pulsatility Index; Heart Rate; Cerebral metabolic rate of oxygen; Positron Emission Tomography; GOS; MCA; Repeated Measures Analysis of Variance; Minute Volume; Transcranial Doppler; Mean Arterial Pressure; CBFV; Transcranial Doppler Flow Velocity; Regional cerebral oxygen saturation; Vmean; GCS; cerebral autoregulation; Cerebral Blood Flow Velocity; PI; Diastolic Velocity; PET
• ISSN: 1878-8750; 1878-8769
• DOI: 10.1016/j.wneu.2016.10.116

Abstract Background The effect of normobaric hyperoxia on brain oxygenation in the presence or absence of intact autoregulation has not been studied till now in acute traumatic brain injury (TBI). Methods In this prospective clinical investigation in fifty patients operated for severe TBI, cerebral blood flow (CBF) velocity in the middle cerebral artery (MCA) was measured using transcranial doppler (TCD). Regional cerebral oxygen saturation (rSO2) using near infra-red spectroscopy (NIRS) at three different inspired oxygen fractions (FiO2 of 0.4, 0.6 and 1) was measured in the later 25 of these patients. Results There was no difference in the hemodynamic and respiratory variables except for PaO2 which increased with increasing FiO2. The CBF velocities and pulsatility indices did not vary at different levels of FiO2 (0.4, 0.6 and 1) both on the operated and non-operated side. The rSO2 as evaluated by bifrontal NIRS sensors, increased with increasing FiO2 on the operated (pathological) side with impaired cerebral autoregulation and not with intact autoregulation. Conclusions In severe TBI, MCA CBF velocity is not affected by hyperoxia in both the pathological and normal side. The cerebral oxygen saturation increased with increasing arterial hyperoxia in the operated cerebral hemisphere while remaining within baseline range in the non-operated hemisphere. Impairment in the cerebral autoregulation in the pathological hemisphere contributes to this luxury oxygenation.