Pressure autoregulation, intracranial pressure, and brain tissue oxygenation in children with severe traumatic brain injury

• Object. Cerebral pressure autoregulation is an important neuroprotective mechanism that stabilizes cerebral blood flow when blood pressure (BP) changes In this study the authors examined the association between autoregulation and clinical factors. BR. intracranial pressure (ICP), brain tissue oxygen tension (PbtO(2)), and outcome after pediatric severe traumatic brain injury (TBI). In particular we examined how the Status 01: autoregulation influenced the effect of BP changes on ICP and PbtO(2) Methods In this prospective observational study. 52 autoregulation tests were performed in 24 patients with severe. TBI. The patients had a mean age of 6.3 +/- 3.2 years. and a postresuscitation Glasgow Coma Scale score of 6 (range 3-8). All patients underwent continuous ICP and MID, monitoring. and transcranial Doppler ultrasonography was, used to examine the autoregulatory index (ARI) based on blood flow velocity of the middle cerebral artery after increasing mean arterial pressure by 20% of the baseline value Impaired autoregulation was defined as an ARI < 0 4 and intact autoregulation as an ART >= 0 4 The relationships between autoregulation (measured as both a Continuous and dichotomous variable), outcome, and clinical and physiological variables were examined using Multiple logistic regression analysis Results. Autoregulation was impaired (ART < 0 4) in 29% of patients (7 patients). The initial Glasgow Coma Scale score was significantly associated with the ARI (p = 0.02, r = 0.32) but no other clinical factors were associated with autoregulation Status. Baseline values at the time of testing for ICP, PbtO(2), the ratio PbtO(2)/PaO2, mean arterial pressure, and middle cerebral artery blood flow velocity were similar in the patients with impaired or intact autoregulation. There was an inverse relationship between ART (continuous and dichotomous) with a chancle in ICP (continuous ARI, p 0.005, dichotomous ARI, p = 0 02): that is. ICP increased with the BP increase when ARI was low (weak autoregulation) The ART (continuous and dichotomous) was also inversely associated with a change in PbtO(2). (continuous ART. p 0.002. dichotomous ARI, p = 0 02). The PbtO(2) increased when BP was increased in most patients, even when the ARI was relatively high (stronger autoregulation). but the magnitude of this response was still associated with the ART. There was no relationship between the ART and Outcome Conclusion. These data demonstrate the influence of the strength of autoregulation on the response of ICP and MO. to BP changes and the variability of this response between individuals The findings suggest that autoregulation testing may assist clinical decision-making in pediatric severe TBI and help better define optimal BP or cerebral perfusion pressure targets for individual patients. (DOI: 10.3171/2009.6.PEDS096)

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Kirurgi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Surgery (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Neurologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Neurology (hsv//eng)

Nyckelord

blood pressure

intracranial pressure

autoregulation

brain tissue oxygen tension

traumatic brain injury

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