Journal of Clinical Monitoring and Computing最新文献

The Nociception Level (NOL) index of the PMD-200™ monitor measures intraoperative nociception-antinociception balance. Because it relies on photoplethysmography, it may be affected by pacemaker interference. We evaluated its response to pacemaker stimulation in the absence of nociceptive input. Mechanically ventilated adults after elective cardiac surgery were studied. NOL index, bispectral index, mean arterial pressure, and heart rate were recorded every minute for 35 min across seven five-minute periods: baseline (pacemaker off), pacing at 90 beats.min^- 1, pacing at 110 beats min^- 1, pacemaker off (washout), pacing at 110 beats min^- 1 (rechallenge), after PMD-200™ recalibration at 110 beats min^- 1, and continued monitoring at 110 beats min^- 1. Data were analysed with mixed-model repeated measures (random intercept for patient, time fixed; bispectral index covariate for NOL). Results are least-square adjusted means ± (standard error), comparing the last minute of each period. Twenty patients were analysed. Pacemaker-induced heart rate changes significantly affected NOL over time (F = 28.420, p < 0.001). Compared with baseline 2.1 ± (1.74), pacing at 90 beats min^- 1 increased NOL to 8.4 ± (1.73) (p = 1.000) and at 110 beats min^- 1 to 18.4 ± (1.73) (p < 0.001). Stopping pacing returned NOL to 1.1 ± (1.73) (p = 1.000), which rose again at 110 beats.min^- 1 rechallenge to 18.0 ± (1.73) (p < 0.001). Recalibration restored baseline values 1.1 ± (1.73) (p = 1.000), with stability maintained during continued monitoring 1.5 ± (1.73) (p = 1.000). The NOL index captured the studied nociception-antinociception balance during pacemaker stimulation when recalibrated to the paced rate. ClinicalTrials.gov: NCT06696781 on 17.11.2024.

Introduction: Haemoglobin measurement is an essential parameter for quantifying anaemia and often used for guiding transfusion decisions. Conventional methods require blood sampling and are invasive. Results are intermittent, discontinuous and obtained after a reasonable acquisition time. Hemoglobinemia by pulsed co-oximetry is non-invasive, immediate and offers the advantage of continuous monitoring. The aim of this systematic review is to assess the diagnostic accuracy of pulsed co-oximetry compared with reference biological determinations in perioperative management.

Methods: The review was registered in PROSPERO and performed according to the PRISMA statement. Searches in Pubmed, Cochrane Library and Scopus databases were performed from January 2000 to February 2024 for studies comparing non-invasive haemoglobin measurement with invasive methods. The QUADAS-2 scale was used to assess the risk of bias. For data analysis, Review Manager 5.4.1 software was employed, using the inverse variance method and a random-effects model to calculate the mean difference (MD) and 95% confidence intervals. Sensitivity analysis were performed in order to assess the influence of site of blood sampling (arterial or venous), revision model reference of the Masimo finger sensor, the geographical location of the study centre, the risk of bias classification, the population type and the type of study.

Results: The meta-analysis included 36 studies involving 1888 patients. Meta-analysis revealed a mean difference between the non-invasive and invasive methods of 0.13 g.dL-1 (95% confidence interval [CI]: 0.10- 0.36) (P-value > 0.05). Sensitivity analyses showed no statistically significant difference between the two methods. There was a very good homogeneity among the studies (I² = 0%). Trending analysis was considered acceptable in a majority of the studies.

Conclusion: The results obtained support the reliability of pulsed co-oximetry. Considering the potential benefits of this parameter, it seems rational to integrate this technology perioperatively to guide standard clinical practices for optimizing the management of surgical patients.

In response to the recent proposal by Monares-Zepeda et al. to estimate mean systemic filling pressure (MSFP) using cardiac power (CP) as a surrogate for the venous return pressure gradient (VRg), we raise concerns regarding the physiological validity and generalizability of the reported correlation. We demonstrate through simulation that the relationship between CP and VRg arises from structural mathematical coupling due to shared dependence on cardiac output (CO), and that this correlation weakens significantly (r = 0.54) when realistic physiological variability is introduced. We further argue that CP and VRg reflect distinct hemodynamic domains, and caution against interpreting their empirical correlation as evidence of physiological interchangeability. We call for broader validation of the model across diverse circulatory conditions. Comment on: 'Presentation of a novel method to estimate analog mean systemic filling pressure based on cardiac power' -on Correlation, Coupling, and Physiological Meaning.

Mean systemic filling pressure (MSFP) is a critical hemodynamic parameter for managing critically ill patients. Existing estimation methods either require invasive procedures or assume constant vascular resistances, limiting their applicability in clinical settings. We propose a novel method to estimate MSFP using cardiac power (CP), this method was developed in a cohort of 50 patients, validated in a different cohort of 50 patients, and tested in a historical cohort of 21 patients, showing a high correlation (r = 0.95 - 0.90) and agreement with Parkin analog Mean Systemic Filling Pressure (MSFPa) method. In brief MSFPe = (3.3*CP) + 2.2 + CVP. Our method provides an accurate, non-invasive bedside approach for estimating MSFP, facilitating hemodynamic assessment in critically ill patients and opening new research avenues on vascular resistance dynamics.

We thank the authors for their interest in our work and their valuable comments. Our response addresses three main points. First, we clarify that the method we presented, deriving mean systemic filling pressure (MSFP) from cardiac power, is a simplification of the Parkin formula. This formula has been validated in both experimental and clinical studies, and we have confirmed its correlation with our approach across different populations. Second, we emphasize the advantage of our method over the Parkin approach: it does not require patient-specific variables such as age, weight, or height, nor does it rely on the assumption of a constant venous-to-arterial compliance ratio (Cv/Ca) of 25:1, which may not always apply. Finally, we identify a critical inconsistency in the authors' simulation model, which yields physiologically impossible values, with venous return resistance exceeding total systemic resistance. This issue highlights the need for further reevaluation.

Healthcare settings heavily rely on clinicians' abilities to interpret vital sign alarms indicating patient decompensation. Meanwhile, clinicians are bombarded with many multisensory stimuli necessary for patient care, including simultaneous visual and auditory displays. Here, we aim to assess how our modified auditory and visual alarm designs impact clinicians' perceived cognitive workload. This experimental study, conducted at Vanderbilt University Medical Center (VUMC) between March and September 2023, included 26 clinicians (nurse practitioners, residents, and fellows). Auditory trials involved 15 clinicians and non-clinicians (university students) to validate design intuitiveness. Clinicians participated in visual and auditory trials to identify simulated mean arterial pressure (MAP), utilizing standard and modified alarms. Visual modifications incorporated a line-graph display with a moving dot for MAP. Auditory modifications introduced harmonic overlays indicating severity and direction of MAP values. After each trial, participants completed the National Aeronautics and Space Administration Task Load Index (NASA-TLX) to assess perceived workload across 6 domains (temporal demand, physical demand, mental demand, effort, performance, frustration) on a 1-20 Likert scale with increased scores represent greater workload. For analysis, Wilcoxon signed-rank and rank-sum tests were used. Demographics for auditory alarm trials averaged an age of 26.2 and 54% identified as male. Visual display trials included 26 clinicians with an average age of 30.1 and 59% identified as male. In visual trials, clinicians reported significantly lower temporal demand with the modified monitor (median, interquartile range (IQR)) (8.0, 4.2-11.8) compared to the conventional monitor (13.0, 6.5-16.0; p = 0.022). In auditory trials, clinicians reported significantly higher perceived performance with conventional auditory alarms as compared to non-clinicians (10.0, 5.0-13.0) vs. (4.0, 2.0-9.0; p = 0.022). Non-clinicians reported higher perceived temporal demand for conventional auditory alarms when compared to clinicians (6.0, 3.0-10.0) vs. (2.5, 1.0-5.0; p = 0.024). Our findings suggest modifications to both visual and auditory alarms can reduce elements of perceived cognitive workload, especially temporal demand, while preserving clinician performance without deterioration of other measured components.