TY - JOUR
T1 - Observations on the Cerebral Effects of Refractory Intracranial Hypertension After Severe Traumatic Brain Injury
AU - Donnelly, Joseph
AU - Smielewski, Peter
AU - Adams, Hadie
AU - Zeiler, Frederick A.
AU - Cardim, Danilo
AU - Liu, Xiuyun
AU - Fedriga, Marta
AU - Hutchinson, Peter
AU - Menon, David K.
AU - Czosnyka, Marek
N1 - Publisher Copyright:
© 2019, The Author(s).
PY - 2020/4/1
Y1 - 2020/4/1
N2 - Background: Raised intracranial pressure (ICP) is a prominent cause of morbidity and mortality after severe traumatic brain injury (TBI). However, in the clinical setting, little is known about the cerebral physiological response to severe and prolonged increases in ICP. Methods: Thirty-three severe TBI patients from a single center who developed severe refractory intracranial hypertension (ICP > 40 mm Hg for longer than 1 h) with ICP, arterial blood pressure, and brain tissue oxygenation (PBTO2) monitoring (subcohort, n = 9) were selected for retrospective review. Secondary parameters reflecting autoregulation (including pressure reactivity index—PRx, which was available in 24 cases), cerebrospinal compensatory reserve (RAP), and ICP pulse amplitude were calculated. Results: PRx deteriorated from 0.06 ± 0.26 a.u. at baseline levels of ICP to 0.57 ± 0.24 a.u. (p < 0.0001) at high levels of ICP (> 50 mm Hg). In 4 cases, PRx was impaired (> 0.25 a.u.) before ICP was raised above 25 mm Hg. Concurrently, PBTO2 decreased from 27.3 ± 7.32 mm Hg at baseline ICP to 12.68 ± 7.09 mm Hg at high levels of ICP (p < 0.001). The pulse amplitude of the ICP waveform increased with increasing ICP but showed an ‘upper breakpoint’—whereby further increases in ICP lead to decreases in pulse amplitude—in 6 out of the 33 patients. Discussion: Severe intracranial hypertension after TBI leads to decreased brain oxygenation, impaired pressure reactivity, and changes in the pulse amplitude of ICP. Impaired pressure reactivity may denote increased risk of developing refractory intracranial hypertension in some patients.
AB - Background: Raised intracranial pressure (ICP) is a prominent cause of morbidity and mortality after severe traumatic brain injury (TBI). However, in the clinical setting, little is known about the cerebral physiological response to severe and prolonged increases in ICP. Methods: Thirty-three severe TBI patients from a single center who developed severe refractory intracranial hypertension (ICP > 40 mm Hg for longer than 1 h) with ICP, arterial blood pressure, and brain tissue oxygenation (PBTO2) monitoring (subcohort, n = 9) were selected for retrospective review. Secondary parameters reflecting autoregulation (including pressure reactivity index—PRx, which was available in 24 cases), cerebrospinal compensatory reserve (RAP), and ICP pulse amplitude were calculated. Results: PRx deteriorated from 0.06 ± 0.26 a.u. at baseline levels of ICP to 0.57 ± 0.24 a.u. (p < 0.0001) at high levels of ICP (> 50 mm Hg). In 4 cases, PRx was impaired (> 0.25 a.u.) before ICP was raised above 25 mm Hg. Concurrently, PBTO2 decreased from 27.3 ± 7.32 mm Hg at baseline ICP to 12.68 ± 7.09 mm Hg at high levels of ICP (p < 0.001). The pulse amplitude of the ICP waveform increased with increasing ICP but showed an ‘upper breakpoint’—whereby further increases in ICP lead to decreases in pulse amplitude—in 6 out of the 33 patients. Discussion: Severe intracranial hypertension after TBI leads to decreased brain oxygenation, impaired pressure reactivity, and changes in the pulse amplitude of ICP. Impaired pressure reactivity may denote increased risk of developing refractory intracranial hypertension in some patients.
KW - Autoregulation
KW - Cerebral hemodynamics
KW - Cerebral oxygenation
KW - Cerebral perfusion pressure
KW - Intracranial hypertension
KW - Intracranial pressure
KW - Traumatic brain injury
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U2 - 10.1007/s12028-019-00748-x
DO - 10.1007/s12028-019-00748-x
M3 - Article
C2 - 31240622
AN - SCOPUS:85068240915
SN - 1541-6933
VL - 32
SP - 437
EP - 447
JO - Neurocritical Care
JF - Neurocritical Care
IS - 2
ER -