Journal of clinical monitoring and computing
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J Clin Monit Comput · Feb 2024
Short-term mild hyperventilation on intracranial pressure, cerebral autoregulation, and oxygenation in acute brain injury patients: a prospective observational study.
Current guidelines suggest a target of partial pressure of carbon dioxide (PaCO2) of 32-35 mmHg (mild hypocapnia) as tier 2 for the management of intracranial hypertension. However, the effects of mild hyperventilation on cerebrovascular dynamics are not completely elucidated. The aim of this study is to evaluate the changes of intracranial pressure (ICP), cerebral autoregulation (measured through pressure reactivity index, PRx), and regional cerebral oxygenation (rSO2) parameters before and after induction of mild hyperventilation. ⋯ Mild hyperventilation can reduce ICP and improve cerebral autoregulation, with minimal clinical effects on cerebral oxygenation. However, the arterial component of rSO2 was importantly reduced. Multimodal neuromonitoring is essential when titrating PaCO2 values for ICP management.
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J Clin Monit Comput · Feb 2024
Cerebral oxygenation saturation in childhood: difference by age and comparison of two cerebral oximetry algorithms.
Few reports are available on the monitoring of regional cerebral oxygen saturation (rSO2) in pediatric patients undergoing non-cardiac surgical procedures. In addition, no study has examined the rSO2 levels in children of a broad age range. In this study, we aimed to assess and compare rSO2 levels in pediatric patients of different age groups undergoing non-cardiac surgery. ⋯ The values in INVOS 5100C and tNIRS-1 were affected by blood pressure and the minimum alveolar concentration of sevoflurane, respectively. In pediatric patients undergoing non-cardiac surgery, rSO2 values differed across the three age groups, and the pattern of these differences varied between the two oximeters employing different algorithms. Further research must be conducted to clarify cerebral oxygenation in children.
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J Clin Monit Comput · Feb 2024
A novel adaptive filter with a heart-rate-based reference signal for esophageal pressure signal denoising.
Esophageal pressure (Peso) is one of the most common and minimally invasive methods used to assess the respiratory and lung mechanics in patients receiving mechanical ventilation. However, the Peso measurement is contaminated by cardiogenic oscillations (CGOs), which cannot be easily eliminated in real-time. The field of study dealing with the elimination of CGO from Peso signals is still in the early stages of its development. ⋯ The CGO can be efficiently suppressed when the constructional reference signal contains the fundamental, and second and third harmonic frequencies of the heart rate signal. The analysis of the data of 8 patients with controlled mechanical ventilation reveals that the standard deviation/mean of the QUOTE is reduced by 28.4-79.2% without changing the QUOTE and the △Pes measurement is more accurate, with the use of our proposed technique. The proposed technique can effectively eliminate the CGOs from the measured Peso signals in real-time without requiring additional equipment to collect the reference signal.
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J Clin Monit Comput · Feb 2024
The 10 Hz dynamic response of a fluid-filled pressure monitoring system is a novel alternative to the fast flush test and indicative of unacceptable systolic pressure overshoot.
The standard method for qualitatively evaluating the dynamic response is to see if the gain of the amplitude spectrum curve approaches 1 (input signal = output signal) over the frequency band of the blood pressure waveform. In a previous report, Watanabe reported that Gardner's natural frequency and damping coefficient, which are widely used as evaluation methods, do not reflect the dynamic response of the circuit. Therefore, new parameters for evaluating the dynamic response of pressure monitoring circuits were desired. ⋯ The difference in systolic blood pressure increased in proportion to the length of the circuit. It could also be inferred that the gain at 10 Hz should be less than 1.2 to meet a clinically acceptable blood pressure difference. In conclusion, the gain at 10 Hz is sufficiently useful as an indicator to determine the correct systolic blood pressure.
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J Clin Monit Comput · Feb 2024
Observational StudyEffects of positive end-expiratory pressure on brain oxygenation, systemic oxygen cascade and metabolism in acute brain injured patients: a pilot physiological cross-sectional study.
Patients with acute brain injury (ABI) often require the application of positive end-expiratory pressure (PEEP) to optimize mechanical ventilation and systemic oxygenation. However, the effect of PEEP on cerebral function and metabolism is unclear. The primary aim of this study was to evaluate the effects of PEEP augmentation test (from 5 to 15 cmH2O) on brain oxygenation, systemic oxygen cascade and metabolism in ABI patients. ⋯ PEEP augmentation test did not affect cerebral and systemic oxygenation or metabolism. Changes in cerebral oxygenation significantly correlated with DO2, SaO2, and VCO2. Cerebral oxygen monitoring could be considered for individualization of mechanical ventilation setting in ABI patients without high or instable intracranial pressure.