Journal of neurosurgical anesthesiology
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J Neurosurg Anesthesiol · Oct 2010
Randomized Controlled TrialNeuromonitoring in carotid surgery: are the results obtained in awake patients transferable to patients under sevoflurane/fentanyl anesthesia?
Diagnostic accuracy studies of neuromonitoring devices during carotid endarterectomy in awake patients are limited by the question of the transferability to anesthetized patients. This study was designed to compare the different neuromonitoring parameters in patients under regional and general anesthesia with stump pressure as the primary endpoint and the courses of cerebral blood flow velocity (Vmca) measured by transcranial Doppler sonography, regional cerebral oxygen saturation (rSO2) measured by near-infrared spectroscopy, and the amplitude of somatosensory evoked potentials (SEP) as the secondary endpoints. ⋯ Carotid artery clamping leads to similar results of stump pressure and similar relative changes of transcranial Doppler sonography, near-infrared spectroscopy, and SEP monitoring in patients under regional and sevoflurane/fentanyl anesthesia.
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J Neurosurg Anesthesiol · Oct 2010
Randomized Controlled TrialDoes nitrous oxide affect bispectral index and state entropy when added to a propofol versus sevoflurane anesthetic?
In earlier studies, nitrous oxide (N2O) did not affect bispectral index (BIS) or state entropy (SE) when administered as the sole anesthetic agent. We investigated the effect of adding N2O to sevoflurane or propofol anesthesia on BIS and SE. ⋯ N2O decreased both BIS and SE when added to sevoflurane, but not propofol. The observed changes in the sevoflurane group were not clinically significant. Decreases in BIS and SE in the sevoflurane group could result from a true additive effect and second-gas effect of N2O that was unaccounted for despite a meticulous titration of sevoflurane using end-tidal gas monitoring.
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J Neurosurg Anesthesiol · Oct 2010
Effects of spontaneous breathing during airway pressure release ventilation on cerebral and spinal cord perfusion in experimental acute lung injury.
Systemic-blood flow, cerebral-blood flow, and spinal cord blood flow can be affected by mechanical ventilation. We investigated the effect of spontaneous breathing on cerebral and spinal blood flow during airway pressure release ventilation (APRV) with and without spontaneous breathing. ⋯ In parallel with higher systemic blood flow regional cerebral and spinal cord blood flow were also higher when spontaneous breathing was maintained during APRV. The higher regional blood flow by maintaining spontaneous breathing was more pronounced when compared with full ventilatory support using high V(T).
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J Neurosurg Anesthesiol · Oct 2010
Heart rate and pulse pressure variability are associated with intractable intracranial hypertension after severe traumatic brain injury.
Calculation of integer heart rate variability (HRVi) permits monitoring over extended periods. We asked whether continuous monitoring of HRVi or integer pulse pressure (PP) variability (PPVi) could predict intracranial hypertension, defined as ICP >20 mm Hg, cerebral hypoperfusion, defined as CPP<60 mm Hg, mortality or functional outcome after severe traumatic brain injury. Dense integer data collected during continuous intensive care unit monitoring for periods of 1 to 11 days on 25 patients admitted to our Level I trauma center with Glasgow Coma Scale <9 provided 1,715,000 data points over a mean 106±62 hours. ⋯ Mean HRVi and PPVi predicted in-hospital mortality (sensitivity, 67%; specificity, 91% to 100%). Combining HRVi and PPVi as an "autonomic index" (AI) best predicted long-term functional outcome [Area Under the Curve: 0.84±0.08 for AI <0.5]. Our data show that HRVi and PPVi can be monitored and calculated automatically and can provide useful prognostic information in patients with severe traumatic brain injury, particularly when combined into a single index.
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J Neurosurg Anesthesiol · Oct 2010
Validity of pulse pressure and systolic blood pressure variation data obtained from a Datex Ohmeda S/5 monitor for predicting fluid responsiveness during surgery.
A simple, inexpensive method is needed for predicting fluid responsiveness in patients during surgery. A previously described method using the Datex Ohmeda S/5 monitor to record arterial and pulse pressure might be accurate enough to use for this purpose. ⋯ There were no significant differences between SPV and PPV estimation using the Ohmeda monitor method and the reference SVV measurement for predicting vascular changes in response to fluid loading. The Ohmeda monitor method requires less sophisticated technology and is much less expensive than other methods.