TY - JOUR
T1 - What comes first? the dynamics of cerebral oxygenation and blood flow in response to changes in arterial pressure and intracranial pressure after head injury
AU - Budohoski, K. P.
AU - Zweifel, C.
AU - Kasprowicz, M.
AU - Sorrentino, E.
AU - Diedler, J.
AU - Brady, Kenneth Martin
AU - Smielewski, P.
AU - Menon, D. K.
AU - Pickard, J. D.
AU - Kirkpatrick, P. J.
AU - Czosnyka, M.
N1 - Funding Information:
This work was supported by the National Institute of Health Research, Biomedical Research Centre (Neuroscience Theme), and National Institute of Health Research Senior Investigator Awards (to J.D.P. and D.K.M.), the Clifford and Mary Corbridge Trust of Robinson College, Cambridge, UK, to K.P.B., the Swiss National Science Foundation (PBBSP3-125550) to C.Z. and the Foundation for Polish Science to M.K.
PY - 2012/1
Y1 - 2012/1
N2 - Background: Brain tissue partial oxygen pressure (PbtO22) and near-infrared spectroscopy (NIRS) are novel Methods to evaluate cerebral oxygenation. We studied the response patterns of PbtO2, NIRS, and cerebral blood flow velocity (CBFV) to changes in arterial pressure (AP) and intracranial pressure (ICP). Methods: Digital recordings of multimodal brain monitoring from 42 head-injured patients were retrospectively analysed. Response latencies and patterns of PbtO2, NIRS-derived parameters [tissue oxygenation index (TOI) and total haemoglobin index (THI)], and CBFV reactions to fluctuations of AP and ICP were studied. Results: One hundred and twenty-one events were identified. In reaction to alterations of AP, ICP reacted first [4.3 s; inter-quartile range (IQR) -4.9 to 22.0 s, followed by NIRS-derived parameters and CBFV (10.9 s; IQR: -5.9 to 39.6 s, 12.1 s; IQR: -3.0 to 49.1 s, 14.7 s; IQR: -8.8 to 52.3 s for THI, CBFV, and TOI, respectively), with PbtO2 reacting last (39.6 s; IQR: 16.4 to 66.0 s). The differences in reaction time between NIRS parameters and PbtO2 were significant (P<0.001). Similarly when reactions to ICP changes were analysed, NIRS parameters preceded PbtO2 (7.1 s; IQR: -8.8 to 195.0 s, 18.1 s; IQR: -20.6 to 80.7 s, 22.9 s; IQR: 11.0 to 53.0 s for THI, TOI, and PbtO2, respectively). Two main patterns of responses to AP changes were identified. With preserved cerebrovascular reactivity, TOI and PbtO2 followed the direction of AP. With impaired cerebrovascular reactivity, TOI and PbtO 2 decreased while AP and ICP increased. In 77 of events, the direction of TOI changes was concordant with PbtO2. ConclusionsNIRS and transcranial Doppler signals reacted first to AP and ICP changes. The reaction of PbtO2 is delayed. The Results imply that the analysed modalities monitor different stages of cerebral oxygenation.
AB - Background: Brain tissue partial oxygen pressure (PbtO22) and near-infrared spectroscopy (NIRS) are novel Methods to evaluate cerebral oxygenation. We studied the response patterns of PbtO2, NIRS, and cerebral blood flow velocity (CBFV) to changes in arterial pressure (AP) and intracranial pressure (ICP). Methods: Digital recordings of multimodal brain monitoring from 42 head-injured patients were retrospectively analysed. Response latencies and patterns of PbtO2, NIRS-derived parameters [tissue oxygenation index (TOI) and total haemoglobin index (THI)], and CBFV reactions to fluctuations of AP and ICP were studied. Results: One hundred and twenty-one events were identified. In reaction to alterations of AP, ICP reacted first [4.3 s; inter-quartile range (IQR) -4.9 to 22.0 s, followed by NIRS-derived parameters and CBFV (10.9 s; IQR: -5.9 to 39.6 s, 12.1 s; IQR: -3.0 to 49.1 s, 14.7 s; IQR: -8.8 to 52.3 s for THI, CBFV, and TOI, respectively), with PbtO2 reacting last (39.6 s; IQR: 16.4 to 66.0 s). The differences in reaction time between NIRS parameters and PbtO2 were significant (P<0.001). Similarly when reactions to ICP changes were analysed, NIRS parameters preceded PbtO2 (7.1 s; IQR: -8.8 to 195.0 s, 18.1 s; IQR: -20.6 to 80.7 s, 22.9 s; IQR: 11.0 to 53.0 s for THI, TOI, and PbtO2, respectively). Two main patterns of responses to AP changes were identified. With preserved cerebrovascular reactivity, TOI and PbtO2 followed the direction of AP. With impaired cerebrovascular reactivity, TOI and PbtO 2 decreased while AP and ICP increased. In 77 of events, the direction of TOI changes was concordant with PbtO2. ConclusionsNIRS and transcranial Doppler signals reacted first to AP and ICP changes. The reaction of PbtO2 is delayed. The Results imply that the analysed modalities monitor different stages of cerebral oxygenation.
KW - brain tissue partial oxygen pressure
KW - cerebral haemodynamics
KW - cerebral oxygenation
KW - cerebrovascular reactivity
KW - near-infrared spectroscopy
KW - tissue haemoglobin index
KW - tissue oxygenation index
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U2 - 10.1093/bja/aer324
DO - 10.1093/bja/aer324
M3 - Article
C2 - 22037222
AN - SCOPUS:84055197926
SN - 0007-0912
VL - 108
SP - 89
EP - 99
JO - British journal of anaesthesia
JF - British journal of anaesthesia
IS - 1
ER -