Journal of Clinical Monitoring and Computing最新文献

Cerebrovascular autoregulation maintains stable cerebral blood flow by counteracting slow changes in cerebral perfusion pressure (termed "slow waves"). Conventional assessment involves invasive techniques using intracranial pressure (ICP) or technically challenging cerebral blood flow velocity (FV) measurements. Near-infrared spectroscopy (NIRS) has emerged as a non-invasive alternative; however, its ability to accurately capture the slow-wave oscillations fundamental to cerebrovascular autoregulation remains uncertain. 412 h of simultaneous ICP, FV, NIRS, and arterial blood pressure (ABP) monitoring from 35 traumatic brain injury patients were explored. Coherence, gain, and Granger causality analyses were employed to assess whether NIRS adequately reflects slow waves in ABP, FV, or ICP to investigate whether NIRS is a suitable alternative for assessing the state of cerebrovascular autoregulation In this single-centre observational cohort study, 89 recordings from 35 moderate to severe traumatic brain injury (TBI) patients (totalling 412 h of artefact-free data) were analysed. Simultaneous high-resolution recordings of NIRS, ICP, FV, and arterial blood pressure (ABP) were acquired. Coherence and gain were computed across defined frequency bands (0.001-0.5 Hz), with a focus on the range most relevant to cerebrovascular autoregulation (0.005-0.05 Hz). Granger causality was used to explore directional relationships between physiological inputs (ABP, FV, ICP) and NIRS outputs (rSO2 and haemoglobin metrics). Haemoglobin-based NIRS metrics (total, oxy-, deoxy-, and delta haemoglobin) demonstrated significantly higher coherence and Granger causality with FV and ICP compared to rSO2 (p < 0.001, large effect sizes) capturing the slow-wave oscillations central to cerebrovascular autoregulation. In contrast, rSO₂ exhibited poor coherence and low causality, especially with ABP, likely due to device-specific post-processing and resolution limitations. NIRS derived haemoglobin metrics reliably capture slow-wave dynamics reflective of cerebrovascular autoregulation and reactivity, offering a non-invasive alternative to traditional methods. Conversely, rSO2 lacks sufficient temporal fidelity to detect these fluctuations under routine clinical conditions, limiting its utility for cerebrovascular autoregulation assessment.

Critically ill patients often require complex extracorporeal treatments, such as extracorporeal blood purification (EBP). At the bedside, there can be reluctance or uncertainty about when to initiate EBP, and there is no standard agreement on which goals to pursue, what prescriptions to use to achieve those goals, or which recommendations to follow to prevent complications. Furthermore, an accurate analysis of why clinical goals are not achieved or how often the patient should be reassessed to readjust the EBP prescription is not currently standardized. This narrative review describes the main actions characterizing a quality improvement program for EBP in the ICU, which took place at the University of Florence and was subsequently adopted at the national level. The pillars of this program were: (1) definition, implementation, and dissemination of information and communication technology tools aimed at objectively measuring results at the bedside, supporting dynamic prescribing and precision medicine, and promoting advances in knowledge in this field; (2) creation of a national multi-professional network of clinical users and researchers in EBP; (3) promotion and maintenance of technical and non-technical skills in EBP based on the reformulation of advanced academic training in this field.

Postoperative delirium (POD) is a common and multifactorial complication following cardiac surgery, with cardiopulmonary bypass (CPB) playing a significant contributory role. Impaired cerebral autoregulation (CA) during CPB, particularly in older patients, may lead to cerebral hypo- or hyperperfusion. While several methods exist to assess CA and cerebral blood flow, many require specialized equipment not widely available. This prospective observational study aimed to investigate whether altered cerebral artery flow velocity, measured preoperatively by transcranial Doppler (TCD), is associated with the development of POD. We enrolled 41 patients undergoing elective cardiac surgery with CPB. Bilateral peak flow velocities of the middle cerebral arteries were measured preoperatively using TCD. The mean middle cerebral artery velocity (mMCAv_mean) was calculated for each patient. POD occurred in 21 patients (51%). A lower mMCAv_mean was significantly associated with an increased risk of POD. Specifically, each 1 cm/s decrease in mMCAv_mean increased the likelihood of POD by 9.2% (odds ratio 0.908; 95% confidence interval: 0.840-0.981; p = 0.015). Reduced cerebral blood flow velocity during CPB, as measured by TCD, is associated with a higher risk of POD. These findings highlight the potential utility of intraoperative TCD monitoring for early identification of at-risk patients and support further research into TCD-guided preventive strategies in cardiac surgery.

Clinical ultrasound in the hands of physicians is rich with experiences from various medical specialties. As point of care ultrasound has revolutionized patient care in the perioperative period, it is important to reflect on the beginnings, and the path taken to modern day portable devices. As anesthesiologists, point of care ultrasound has become embedded into all aspects of perioperative care to improve patient outcomes. Advancements in technology continue to extend the boundaries for use by anesthesiologists and redefine the standard of care in the perioperative period. This article reflects on the path of point-of-care ultrasound from its beginning to the present day and discusses future directions. A summary of key findings is shown.

To evaluate the effects of three simple bedside challenges on cerebral oxygenation and brain activity, measured non-invasively using near-infrared spectroscopy (NIRS) and frontal single-channel electroencephalography (EEG), in comatose post-cardiac arrest patients, and to examine whether these responses differ according to cerebral autoregulation status and intensive care unit (ICU) outcome and could aid early prognostication. Three bedside physiological challenges were conducted: (1) increasing the fraction of inspired oxygen (FiO₂) to 100%, (2) lowering the head-of-bed (HOB) to 0°, and (3) elevating end-tidal carbon dioxide (etCO₂) by 1.0 kPa. Tissue oxygen saturation (StO₂) and EEG amplitude were hypothesized to increase, by enhancing oxygen delivery (FiO₂), augmenting cerebral perfusion pressure (HOB), and inducing cerebral vasodilation (etCO₂). Furthermore, we examined the associations between signal responses, cerebral autoregulation status, and ICU outcome. Of the 48 monitored patients, FiO₂, HOB, and etCO₂ challenges were successfully completed in 41 (85%), 33 (69%), and 32 (67%) patients, respectively. The StO₂ increased on average by 0.3% (95%-CI 0.2-0.5, p < 0.001) for every 10% rise in FiO₂, and 1.94% (95%-CI 0.9-3.0, p < 0.001) for each 15º lowering of the HOB. The etCO₂ challenge did not affect the StO₂. EEG amplitude remained unchanged during all three challenges. No significant differences were found in the responses between patients with intact versus impaired autoregulation or between the ICU outcome groups. Brief physiological challenges simulating common ICU scenarios elicited only modest increases in StO₂, and no measurable response in EEG amplitude. Response patterns were not associated with cerebral autoregulation status or ICU outcome.

Depth-of-anesthesia monitoring, particularly in functional neurosurgical procedures such as asleep deep brain stimulation, is critical for balancing individualized neurophysiological needs with perioperative safety. Parkinson's disease (PD) patients with rapid-eye-movement sleep behavior disorder (RBD) demonstrate wakefulness electroencephalographic (EEG) abnormalities that may confound monitoring. Whether these RBD-associated EEG patterns persist under propofol anesthesia and distort monitoring indices remains to be elucidated. This study therefore aimed to determine if propofol anesthesia in PD-RBD patients disrupts coherence between anesthesia depth indices and true neurophysiological states. We retrospectively analyzed SedLine^®-monitored prefrontal EEG data from 43 PD patients undergoing subthalamic nucleus deep brain stimulation, divided into non-RBD (n = 23) and RBD (n = 20) groups. Evaluations were conducted across awake, propofol anesthesia, and propofol light anesthesia states during microelectrode recording, including power spectral density analysis, derived parameter comparisons, and postoperative outcomes. Results showed RBD patients had lower patient state index values during wakefulness (p = 0.034) but displayed comparable patient state index, spectral edge frequency, and suppression ratio under anesthesia; notably stronger gamma suppression occurred in RBD patients during propofol anesthesia (p = 0.027) and light anesthesia states (p = 0.011), along with higher postoperative delirium incidence (65.00%). Logistic regression identified associations between postoperative delirium risk and RBD status, Mini-Mental State Examination scores, and propofol-induced theta power, with theta power emerging as a protective factor. Collectively, PD-RBD patients exhibit abnormal EEG under propofol anesthesia but maintain reliable depth-of-anesthesia indices, necessitating customized anesthesia care and delirium prevention. Clinical Trial Number: ChiCTR2400082770, 2024-04-07, ClinicalTrials.gov).

The Mean flow index (Mxa) is widely used to assess dynamic cerebral autoregulation in different clinical populations. This calculation is based on defined characteristics, including blocks, overlap periods, and epochs of the whole recordings. This study aimed to investigate the reproducibility of different Mxa calculations, using variable blocks, overlap periods, and epochs. We retrospectively analyzed 50 transcranial Doppler recordings from septic shock patients, acquired within 48 h of ICU admission. Mxa was computed using eight signal-processing strategies that varied by block duration (5-10 s), overlap percentage (20%, 50%, 80%), and epoch length (3-5 min), as well as a continuous approach without epochs. Each configuration was labeled using the format epoch-block-overlap. Mxa values were compared using repeated measures analyses, intraclass correlation coefficients (ICC), Bland-Altman plots, and polychoric correlation heatmaps. Median Mxa values ranged from 0.36 to 0.45 across configurations, with no statistically significant differences in within-patient comparisons (p > 0.05). ICCs demonstrated excellent agreement (ICC > 0.90) between approaches using the same epoch duration. Agreement declined modestly when comparing configurations with different epoch lengths (e.g., ICC = 0.782 between 3-10-50 and 5-10-50). Fixed-effects analysis did not identify any individual segmentation parameter as a significant source of variability. Mxa values calculated using different combinations of block, overlap, and epoch duration were consistent within patients, particularly when epoch length was maintained. These findings support the reproducibility of Mxa and suggest flexibility in processing strategies, provided methodological consistency is maintained. Further validation is warranted.