Cerebral circulation after head injury

Overgaard, J.; Tweed, W. A.

doi:10.3171/jns.1974.41.5.0531

Cited by 280 publications

(21 citation statements)

References 17 publications

(2 reference statements)

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“…The observed difference between positional rCBF changes in the brain-injured versus healthy cohorts is consistent with prior studies of cerebral hemodynamics that have demonstrated impaired cerebrovascular autoregulation in severely brain-injured patients [43–48]. Furthermore, the variability in frontal cortical cerebrovascular responses to posture change observed in the brain-injured cohort is consistent with similarly heterogeneous results in prior studies that examined the effect of head-of-bed position on CBF.…”

Section: Discussionsupporting

confidence: 87%

Continuous Optical Monitoring of Cerebral Hemodynamics During Head-of-Bed Manipulation in Brain-Injured Adults

et al. 2013

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Introduction Head-of-bed manipulation is commonly performed in the neurocritical care unit to optimize cerebral blood flow (CBF), but its effects on CBF are rarely measured. This pilot study employs a novel, non-invasive instrument combining two techniques, diffuse correlation spectroscopy (DCS) for measurement of CBF and near-infrared spectroscopy (NIRS) for measurement of cerebral oxy- and deoxy-hemoglobin concentrations, to monitor patients during head-of-bed lowering. Methods Ten brain-injured patients and ten control subjects were monitored continuously with DCS and NIRS while the head-of-bed was positioned first at 30° and then at 0°. Relative CBF (rCBF) and concurrent changes in oxy- (ΔHbO2), deoxy- (ΔHb), and total-hemoglobin concentrations (ΔTHC) from left/right frontal cortices were monitored for 5 minutes at each position. Patient and control response differences were assessed. Results rCBF, ΔHbO2, and ΔTHC responses to head lowering differed significantly between brain-injured patients and healthy controls (P<0.02). For patients, rCBF changes were heterogeneous, with no net change observed in the group average (0.3% ± 28.2%, P=0.938). rCBF increased in controls (18.6% ± 9.4%, P<0.001). ΔHbO2, ΔHb, and ΔTHC increased with head lowering in both groups, but to a larger degree in brain-injured patients. rCBF correlated moderately with changes in cerebral perfusion pressure (R=0.40, P<0.001), but not intracranial pressure. Conclusion DCS/NIRS detected differences in CBF and oxygenation responses of brain-injured patients versus controls during head-of-bed manipulation. This pilot study supports the feasibility of continuous bedside measurement of cerebrovascular hemodynamics with DCS/NIRS and provides the rationale for further investigation in larger cohorts.

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Section: Discussionsupporting

confidence: 87%

Continuous Optical Monitoring of Cerebral Hemodynamics During Head-of-Bed Manipulation in Brain-Injured Adults

et al. 2013

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“…44,45 The persistent 50% reduction in CBF is consistent with the findings from other TBI animal models, 44,46 as well as human TBI patients. 47 Bouma et al reported CBF values of <25 mL/min/100 g in adult patients with severe TBI within the first few hours of hospital admission, while normal CBF in adult humans is 45–50 mL/min/100 g. 48 A 40–50% CBF reduction persisting for at least 4 h has been reported in rats following fluid percussion injury (FPI). 46 FPI in neonatal piglets has been shown by Ref.…”

Section: Discussionmentioning

confidence: 99%

Diffuse optical monitoring of hemodynamic changes in piglet brain with closed head injury

et al. 2009

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We used a nonimpact inertial rotational model of a closed head injury in neonatal piglets to simulate the conditions following traumatic brain injury in infants. Diffuse optical techniques, including diffuse reflectance spectroscopy and diffuse correlation spectroscopy (DCS), were used to measure cerebral blood oxygenation and blood flow continuously and noninvasively before injury and up to 6 h after the injury. The DCS measurements of relative cerebral blood flow were validated against the fluorescent microsphere method. A strong linear correlation was observed between the two techniques (R = 0.89, p < 0.00001). Injury-induced cerebral hemodynamic changes were quantified, and significant changes were found in oxy- and deoxy-hemoglobin concentrations, total hemoglobin concentration, blood oxygen saturation, and cerebral blood flow after the injury. The diffuse optical measurements were robust and also correlated well with recordings of vital physiological parameters over the 6-h monitoring period, such as mean arterial blood pressure, arterial oxygen saturation, and heart rate. Finally, the diffuse optical techniques demonstrated sensitivity to dynamic physiological events, such as apnea, cardiac arrest, and hypertonic saline infusion. In total, the investigation corraborates potential of the optical methods for bedside monitoring of pediatric and adult human patients in the neurointensive care unit.

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“…Conversely, when CPP is above the upper limit, passive vasodilation occurs. Using measures of CBF including intra-arterial xenon clearance (38) and TCD FV of the MCA (39), it has been demonstrated that disordered cerebral autoregulation occurs after severe TBI and is associated with worse outcome.…”

Section: Concepts and Historical Perspectivementioning

confidence: 99%

Monitoring of Intracranial Pressure in Patients with Traumatic Brain Injury

2014

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Since Monro published his observations on the nature of the contents of the intracranial space in 1783, there has been investigation of the unique relationship between the contents of the skull and the intracranial pressure (ICP). This is particularly true following traumatic brain injury (TBI), where it is clear that elevated ICP due to the underlying pathological processes is associated with a poorer clinical outcome. Consequently, there is considerable interest in monitoring and manipulating ICP in patients with TBI. The two techniques most commonly used in clinical practice to monitor ICP are via an intraventricular or intraparenchymal catheter with a microtransducer system. Both of these techniques are invasive and are thus associated with complications such as hemorrhage and infection. For this reason, significant research effort has been directed toward development of a non-invasive method to measure ICP. The principle aims of ICP monitoring in TBI are to allow early detection of secondary hemorrhage and to guide therapies that limit intracranial hypertension (ICH) and optimize cerebral perfusion. However, information from the ICP value and the ICP waveform can also be used to assess the intracranial volume–pressure relationship, estimate cerebrovascular pressure reactivity, and attempt to forecast future episodes of ICH.

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Cerebral circulation after head injury

Cited by 280 publications

References 17 publications

Continuous Optical Monitoring of Cerebral Hemodynamics During Head-of-Bed Manipulation in Brain-Injured Adults

Continuous Optical Monitoring of Cerebral Hemodynamics During Head-of-Bed Manipulation in Brain-Injured Adults

Diffuse optical monitoring of hemodynamic changes in piglet brain with closed head injury

Monitoring of Intracranial Pressure in Patients with Traumatic Brain Injury

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