Computer supported multimodal bed-side monitoring for neuro intensive care

Czosnyka, Marek; Whitehouse, Helen; Smielewski, Peter; Kirkpatrick, Peter J.; Guazzo, E.; Pickard, John D.

doi:10.1007/bf01139874

Cited by 74 publications

(25 citation statements)

References 13 publications

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“…28,29 Maximum physiological stability is generally observed at the time of application of clamps rather than removal; therefore, data from this period were used for analysis. Values of mean arterial pressure, laser Doppler flowmetry, FV and TOI were averaged at baseline (before clamping but after completion of dissection) and over a 2-minute period immediately after ECA and ICA clamping.…”

Section: Data Processing and Analysismentioning

confidence: 99%

Tissue Oxygen Index

Al-Rawi

Kirkpatrick

2006

Stroke

149

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Background and Purpose-To date, the clinical application of near infrared spectroscopy in the adult brain has been limited. The NIRO 300 (Hamamatsu Photonics) provides a continuous measurement of tissue oxygen index (TOI) using spatially resolved spectroscopy. Although TOI reflects cerebral oxygenation to a high degree of sensitivity and specificity, to become a useful clinical tool, thresholds for cerebral ischemia need to be defined. This study has attempted to identify a quantifiable TOI threshold for ischemia in the adult brain. Methods-One hundred sixty-seven patients undergoing carotid endarterectomy were studied. The NIRO 300 was incorporated into an established multimodal monitoring system enabling observations of cerebral hemodynamic changes under highly controlled conditions. Changes in TOI (%⌬TOI) on clamping the internal carotid artery were compared with intracranial blood flow (middle cerebral artery flow velocity) and cerebral function monitoring to identify and quantify periods of cerebral ischemia. Results-Significant correlation was seen between changes in middle cerebral artery flow velocity and ⌬TOI on clamping (rϭ0.74, Pϭ0.0001). Thirty-one patients showed cerebral ischemia on internal carotid artery clamping as defined by a sustained fall in cerebral function monitoring. A threshold for %⌬TOI of Ϫ13 was identified, above which no patients showed any evidence of ischemia on clamping. This threshold provided 100% sensitivity and 93.2% specificity for patients satisfying the preset criteria for cerebral ischemia. Conclusions-These data demonstrate the potential to identify TOI-quantified thresholds for cerebral ischemia in the adult brain and thus improve the clinical use of near infrared spectroscopy. Our observations have defined a drop in TOI (13%) that can be adopted as a threshold for severe cerebral ischemia with high sensitivity and specificity. Key Words: carotid endarterectomy Ⅲ cerebral ischemia Ⅲ near infrared spectroscopy Ⅲ spatially resolved spectroscopy Ⅲ tissue oxygen index O ptical methods based on near-infrared spectroscopy (NIRS) can be used to monitor hemodynamic variables in the clinical setting. 1 Applications include monitors of fetal physiology, 2-4 during cardiac surgery, 5,6 muscle function, 7-10 and neonatal, 11 pediatric, 12 and adult brain. [13][14][15][16][17][18][19] A number of NIRS instruments are now available that detect changes in optical attenuation from several wavelengths of light, and although a variety of algorithms have been applied to attempt quantification, accuracy of these instruments remains a concern.The NIRO 300 (Hamamatsu Photonics) provides a continuous online measurement of tissue oxygen index (TOI) using spatially resolved spectroscopy. 20,21 We have previously determined that TOI reflects cerebral oxygenation to a high degree of sensitivity and specificity during carotid surgery, 20 an indication that NIRS can show clinically relevant estimations of cerebral hemodynamic and oxygen changes in the adult head (Figure 1). However, there are no da...

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Section: Data Processing and Analysismentioning

confidence: 99%

Tissue Oxygen Index

Al-Rawi

Kirkpatrick

2006

Stroke

149

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“…23 Sampling frequency was 30 Hz. Time-averaged means for MAP, ICP, and CPP (CPPϭMAPϪICP) were calculated and stored every 6 seconds.…”

Section: Determination Of Autoregulationmentioning

confidence: 99%

Assessment of Cerebrovascular Autoregulation in Head-Injured Patients

Steiner

Coles

Johnston

et al. 2003

Stroke

160

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Background and Purpose-Cerebrovascular autoregulation is frequently measured in head-injured patients. We attempted to validate 4 bedside methods used for assessment of autoregulation. Methods-PET was performed at a cerebral perfusion pressure (CPP) of 70 and 90 mm Hg in 20 patients. Cerebral blood flow (CBF) and cerebral metabolic rate for oxygen (CMRO 2 ) were determined at each CPP level. Patients were sedated with propofol and fentanyl. Norepinephrine was used to control CPP. During PET scanning, transcranial Doppler (TCD) flow velocity in the middle cerebral artery was monitored, and the arterio-jugular oxygen content difference (AJDO 2 ) was measured at each CPP. Autoregulation was determined as the static rate of autoregulation based on PET (SROR PET ) and TCD (SROR TCD ) data, based on changes in AJDO 2 , and with 2 indexes based on the relationship between slow waves of CPP and flow velocity (mean velocity index, Mx) and between arterial blood pressure and intracranial pressure (pressure reactivity index, PRx) Results-We found significant correlations between SROR PET and SROR TCD (r 2 ϭ0.32; PϽ0.01) and between SROR PET and PRx (r 2 ϭ0.31; PϽ0.05). There were no significant associations between PET data and autoregulation as assessed by changes in AJDO 2 . Global CMRO 2 was significantly lower at the higher CPP (PϽ0.01). Conclusions-Despite

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“…To explore the relationship between FR and ICP, a mean ICP was calculated over the time period during which each individual vial was collecting fluid, using the ICMplus software (University of Cambridge, Cambridge, UK) (Czosnyka et al, 1994). This allows a direct comparison of the FR in each vial with the mean ICP over the time the vial was collecting fluid.…”

Section: Microdialysis Methodologymentioning

confidence: 99%

The Cytokine Response to Human Traumatic Brain Injury: Temporal Profiles and Evidence for Cerebral Parenchymal Production

Helmy

Carpenter

Menon

et al. 2010

J Cereb Blood Flow Metab

294

318

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The role of neuroinflammation is increasingly being recognised in a diverse range of cerebral pathologies, including traumatic brain injury (TBI). We used cerebral microdialysis and paired arterial and jugular bulb plasma sampling to characterise the production of 42 cytokines after severe TBI in 12 patients over 5 days. We compared two microdialysis perfusates in six patients: central nervous system perfusion fluid and 3.5% human albumin solution (HAS); 3.5% HAS has a superior fluid recovery (95.8 versus 83.3%), a superior relative recovery in 18 of 42 cytokines (versus 8 of 42), and a qualitatively superior recovery profile. All 42 cytokines were recovered from the human brain. Sixteen cytokines showed a stereotyped temporal peak, at least twice the median value for that cytokine over the monitoring period; day 1: tumour necrosis factor, interleukin (IL)7, IL8, macrophage inflammatory protein (MIP)1a, soluble CD40 ligand, GRO, IL1b, platelet derived growth factor (PDGF)-AA, MIP1b, RANTES; day 2: IL1 receptor antagonist (ra). IL6, granulocyte-colony stimulating factor (G-CSF), chemokine CXC motif ligand 10 (IP10); days 4 to 5: IL12p70, IL10. Brain extracellular fluid concentrations were significantly higher than plasma concentrations for 19 cytokines: basic fibroblast growth factor (FGF2), G-CSF, IL1a, IL1b, IL1ra, IL3, IL6, IL8, IL10, IL12p40, IL12p70, IP10, monocyte chemotactic protein (MCP)1, MCP3, MIP1a, MIP1b, PDGF-AA, transforming growth factor (TGF)a and vascular endothelial growth factor. No clear arterio-jugular venous gradients were apparent. These data provide evidence for the cerebral production of these cytokines and show a stereotyped temporal pattern after TBI.

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Computer supported multimodal bed-side monitoring for neuro intensive care

Cited by 74 publications

References 13 publications

Tissue Oxygen Index

Tissue Oxygen Index

Assessment of Cerebrovascular Autoregulation in Head-Injured Patients

The Cytokine Response to Human Traumatic Brain Injury: Temporal Profiles and Evidence for Cerebral Parenchymal Production

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