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, pacing at 110 beats min, pacemaker off (washout), pacing at 110 beats min (rechallenge), after PMD-200™ recalibration at 110 beats min, and continued monitoring at 110 beats min. 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 increased NOL to 8.4 ± (1.73) (p = 1.000) and at 110 beats min 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 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.

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.

To evaluate whether a web-based Intraoperative Glycemic Protocol Calculator (IGPC) improves provider compliance with intraoperative glycemic management protocols during cardiac surgery. Single-center retrospective cohort study conducted between August - October 2022 (pre-intervention) and April - June 2023 (post-intervention). Tertiary care academic hospital. Adult patients undergoing coronary artery bypass grafting and/or valve surgery requiring cardiopulmonary bypass. Implementation of the IGPC, a web-based clinical decision support tool designed to automate insulin dosing recommendations intraoperatively. Protocol adherence, defined as appropriate insulin administration within five minutes of glucose measurement, was compared before and after IGPC implementation. Among 143 patients, IGPC use significantly increased adherence across all intraoperative phases: Pre-CPB (65.5% to 80.2%, p = 0.017), On-CPB (53.0% to 75.1%, p < 0.001), and Post-CPB (34.8% to 58.8%, p < 0.001). Rates of severe hypoglycemia remained low and unchanged (0.1% in both groups; p = 0.772), and intraoperative hyperglycemia rates were similar (4.2% vs. 4.1%; p = 0.995). Implementation of the IGPC significantly improved real-time adherence to intraoperative glycemic control protocols without increasing adverse glycemic events. However, rates of intraoperative hyperglycemia and hypoglycemia remained unchanged between the pre- and post-intervention phases. These findings highlight the utility of clinical decision support tools in enhancing protocol compliance during high-acuity cardiac surgeries.

Ultrasound Elastography (UE) tends to improve the ultrasound diagnosis accuracy. The Strain Elastography (SE) depicts the pathological tissue loss of elasticity in response to an external pressure applied by the operator. It is now recommended for benign/malignant parenchymal process differentiation and for muscle and nervous rigidness assessment and follow-up. The SE was able to differentiate the normal nerves from their muscular-vascular environment based on their own elasticity using a colorimetric scale (CS)0.30 healthy adult patients were included into this prospective observational study. The femoral nerve (FN) and the popliteal sciatic nerve (PSN) were studied using 2D black and white sonography (S) and SE. About the SE, firstly, CS goes from red (stiffer) to blue (softer) differentiating 6 main colors at the visual assessment. Secondly, the CS was transformed into a 3 points tissues classification related to FN and PSN elasticity for easier reading. Results are presented as percentages.FN and PSN in sonography were normal in all patients confirming the different morphology of each kind of nerve with a high level of patient-to-patient reproducibility. SE detected as "stiff" the FN and PSN in respectively 87 and 83% of the patients. Finally, a superposition between sonogram and elastogram greater than 50% was observed in 54 and 70% of the patients.SE represents a promising technique that may complement S to try to improve the quality of nerve localization. Further and larger studies are needed for a better understanding the subject in real clinical conditions.

Traditional assessments using carboxyhemoglobin (COHb) levels alone often do not adequately predict clinical course of carbon monoxide (CO) poisoning cases. Perfusion index (PI) and pleth variability index (PVI) offer non-invasive, continuous monitoring of peripheral perfusion, potentially improving patient management. The objective of this study is to evaluate whether perfusion indices can assist in triage and monitoring of patients with CO poisoning.

This study aimed to evaluate whether continuous axillary temperature monitoring using a wearable patch enables earlier detection of postoperative infections compared to conventional intermittent infrared thermometry. 103 surgical patients were included in this prospective, single-center study and monitored over an 11-month period. Continuous axillary temperature monitoring using the SteadyTemp patch was compared to routine infrared measurements performed as part of clinical routine. The primary outcome was fever detection rate (≥ 38.0 °C). Secondary outcomes included the correlation between fever detection and laboratory values as well as the frequency of clinical interventions. Out of 103 included patients, fever was detected in 33 cases. Continuous monitoring identified fever in 31 of these 33 patients (93.9%), whereas infrared thermometry detected fever in only 12 cases (36.4%). In 16 cases where antibiotic therapy was initiated or adjusted due to newly detected fever, the patch detected fever in 15 patients, compared to only 7 detections by infrared thermometry. Surgical interventions due to suspected infections were performed in 5 patients, and fever was detected by the patch in all cases, while infrared thermometry detected fever in only 2 of these patients. Due to the frequent failure of infrared thermometry to detect fever, a scoring system was developed to assess the clinical relevance of fever detection. Continuous temperature monitoring with the SteadyTemp patch demonstrated superior fever detection compared to infrared thermometry, leading to earlier identification of febrile events. This study suggests that continuous temperature monitoring may enhance infection surveillance in surgical patients, allowing for more timely clinical interventions.

Respiratory rate is an important early sign of clinical deterioration but the current practice of counting breaths manually is time-consuming and prone to error. We aimed to determine the concordance between manual respiratory rate measurements and automated measurements recorded using a wearable device. We undertook a prospective observational study on three general respiratory wards to compare manual respiratory rate measurements collected during usual clinical care with automated readings from a wearable respiratory rate monitor (RespiraSense, PMD Solutions, Cork, Ireland). Thirty-one patients took part in the study. Manual respiratory rate readings displayed large peaks at 20 and 24 breaths/min, whereas automated readings followed a smooth bell-shaped distribution. Manual and automated respiratory rates were both higher during the day than at night, and this was more marked for automated readings. Automated readings were on average 2.5 (95% confidence interval [CI] 2.2 to 2.8) breaths/minute higher than time-matched manual readings, and the 95% limits of agreement were - 7.9 (95% CI -8.4 to -7.4) and 12.9 (95% CI 12.3 to 13.4) breaths/minute, wider than the clinically acceptable limits of ± 3 breaths/min. Trends in manual and automated respiratory rates were concordant in only 56% of cases. Automated respiratory rate measurements using RespiraSense do not display clinically acceptable agreement with manual measurements in the setting of a respiratory ward.

Stroke volume variation (SVV) is a dynamic parameter used to assess fluid responsiveness in mechanically ventilated patients. This study aimed to evaluate the agreement and trending ability of SVV measurements obtained from bioreactance (Starling SV) and arterial waveform analysis devices (FloTrac and LiDCOrapid) during cardiac surgery.

Intensive care units (ICUs) handle mechanically ventilated patients with life-threatening conditions, who require intensive monitoring and treatment. In a low physician-patient ratio setting, providing consistent care to all patients is challenging. A survival prediction model using machine-learning can potentially improve prognosis evaluation and resource allocation. This study aims to develop a machine-learning model to predict survival/mortality in mechanically ventilated patients using clinical features recorded at the time of ICU admission and compare its performance with the Sequential Organ Failure Assessment (SOFA) score as a standalone predictor.

Vegetative reactions are common during neurosurgical procedures. Known effects are mainly cardiovascular, including tachy- and bradyarrhythmia, hyper- and hypotonia as well as cardiac arrest. Computer-assisted real-time analysis of heart rate variability (HRV), baroreflex-sensitivity (BRS) allows for continuous evaluation of the autonomic nervous system (ANS). We analyzed ANS parameters during intracranial neurosurgical procedures. In this pilot study, we aim to provide proof-of-concept that ANS monitoring during surgery is feasible and yields stable results.We included 129 consecutive patients undergoing neurosurgery for intracranial pathologies over a period of four months. Heart rate (HR) and mean arterial pressure (MAP) were continuously monitored during routine anesthesiology care. Data were recorded via ICM + software. HRV, BRS and other vegetative parameters were calculated continuously. Intraoperative events such as hypo-/hypertonia or brady-/tachycardia were monitored.Mean age was 47.2 ± 17.7 years. Of all patients, 54.3% were male (n = 70). For every patient, four intraoperative episodes were defined: start of anesthesia until incision - start of incision until craniotomy - craniotomy until end of resection or intracranial manipulation - end phase until skin closure. BRS continuously decreased during cranial surgery, indicating stabilized autonomic function. Furthermore, blood pressure variability was increased during semi-sitting surgery.Autonomic system monitoring during neurosurgical procedures is safe and feasible. Intraoperatively, an increasing sympathetic activity has been observed without clear disctinction between surgical or anesthesiological events as underlying cause. Monitoring results are reproducible and may be of importance for the detection and prevention of intraoperative cardiovascular events.

The Analgesia Nociception Index (ANI) is based on respiratory sinus arrhythmia and is a validated surrogate marker of the nociception-antinociception balance. Along with the ANI, the monitor provides a measure of overall heart rate variability modulation named "Energy" and which is closely related to the standard deviation of normal R-R intervals. The objective of the present study was to evaluate variations in "Energy" during general anesthesia, sedation, and spinal anesthesia. We retrospectively analyzed data stored in the anesthesia data warehouse at Lille University Medical Center (Lille, France). Eligible cases involved general anesthesia, spinal anesthesia, or sedation over the period 2012-2024. Patients with arrhythmia or missing baseline data were excluded. Three periods were defined: pre-induction (P1), post-induction (P2), and intraoperative (P3). Linear mixed models were adjusted for age, the American Society of Anesthesiologists score, norepinephrine use, and sex. 2226 procedures were included. The decrease in "Energy" after induction was significantly greater for general anesthesia after adjustment between P1 and P2 (Mean (SD) -0.306 (-0.321; -0.292), p < 0.001) and between P1 and P3 (-0.334 (-0.348; -0.319), p < 0.001). Same results were found for sedation (P1-P2: -0.120 (-0.176; -0.064), p < 0.001; P1-P3: -0.113 (-0.168; -0.056), p < 0.001) and spinal anesthesia (P1-P2: 0.082 (0.017; 0.146), p = 0.012; P1-P3: 0.089 (0.025; 0.153), p = 0.006) after adjustment. Changes during sedation and spinal anesthesia were not clinically relevant. "Energy" decreases after the induction of general anesthesia and sedation and thus reflects a lower degree of autonomic modulation.

Functional testers are designed to evaluate select pulse oximeter characteristics but are often misused to validate device accuracy, potentially providing false reassurance. This study evaluated whether the Fluke ProSim8 (FPS8) could accurately predict oximeter performance during human controlled desaturation studies or identify performance differences under low signal conditions. 12 oximeters were tested using two FPS8 protocols: (1) an 'SpO₂ plateau' protocol which mimicked controlled desaturation studies by evaluating device performance over a range of simulated SpO (70-100%), and (2) a 'signal space' protocol designed to assess device accuracy under varying modulation and transmission conditions. Each device also underwent controlled desaturation testing in healthy adults. Six of the 12 oximeters passed (ARMS ≤ 3%) the SpO₂ plateau protocol; however, three of these failed (ARMS > 3%) human testing. At lower simulated saturations, most devices overestimated SpO₂. In the signal space protocol, oximeters performed well under high signal conditions, but many failed to produce readings or showed SpO₂ errors > 3% under low signal conditions. On average, oximeters failed to generate a reading 20.2 ± 7.2 times out of 60 attempts. Ten devices passed (ARMS < 3%) the signal space protocol, but two of these failed human testing. Oximeter performance on the FPS8 did not correlate with human performance (R² = 0.08 for the plateau protocol; R² = 0.01 for the signal space protocol). The FPS8 did not reliably predict oximeter accuracy in human desaturation studies or under low signal conditions; current functional tester protocols are limited in predicting real-world oximeter performance.

Electrical impedance tomography (EIT) is a functional imaging technique to monitor regional ventilation. However, the quantification of clinically used ventilation parameters like tidal volume (VT) has not been possible yet since EIT measures relative and not absolute changes in impedance. Thus, the study aimed to evaluate the relationship between impedance changes (dZ) and VT in humans and to identify influencing factors.

Reduce sevoflurane consumption during anaesthesia remains an economic and environmental challenge. This case study analyzed retrospectively a large cohort of procedures using end-tidal (ET) Control to optimize sevoflurane consumption and assess the impact of ventilator settings on it. In single center, consecutive adult procedures for noncardiac surgery under general anaesthesia were analyzed in twelve operating rooms. The anaesthesia system (Aisys CS, GE, USA) was connected to software (Carestation Insight, GE, USA) that automatically recorded sevoflurane consumption for each case. Left to the discretion of the anaesthesiologist, fresh gas flow (FGF) was set at 0.5, 0.8 or 1 L.min with an initial end-tidal sevoflurane target of 1.2-2% to reach the goal of approximately 1.0 MAC. The primary endpoint was the sevoflurane consumption (mL.min). Secondary endpoints were sevoflurane consumption and carbon footprint for the cohort (sevoflurane GWP = 702) and by anaesthesia duration, type of airway management (endotracheal intubation EI, laryngeal mask LM), FGF and initial sevoflurane settings. From May to September 2024, 3064 procedures were recorded via the app. with a median (IQR) duration of surgery of 79 (47-124) minutes. Sevoflurane consumption was. 19 528 mL. Median (IQR) sevoflurane consumption was 0.16 (0.12-0.20) mL.min with a carbon footprint (sevoflurane GWP including manufacturing = 1,468 kg/mL) of 0,23(0.17-0.29) kgCO.min.Subgroup analysis demonstrated that FGF at 0.8 or 1.0 L.min significantly increased sevoflurane consumption and CO emission when compared with 0.5 L.min (P < 0.01). Initial ET target sevoflurane levels of 1.2% vs greater than 1.2% did not change total sevoflurane consumption. Regarding airway management (EI vs LM), LM use was associated with higher consumption, specifically when duration > 120 min (P < 0.01). In this large cohort of cases, this study demonstrated that controlling ET with an FGF target of 0.5 L.min remained the best way to reduce sevoflurane consumption. Other settings did not significantly reduce gas consumption.

Burn shock is a major early complication in the treatment of severely burned patients, and precise and timely fluid management is essential for survival. Traditional clinical indicators such as urine output, blood pressure, central venous pressure (CVP), and blood lactate are commonly used, but each has significant limitations. Invasive hemodynamic monitoring technologies, such as Pulmonary Artery Catheterization (PAC) and Pulse Contour Cardiac Output (PiCCO), have improved the accuracy of fluid assessment, but carry risks of infection and procedural complications and require experienced clinical interpretation within the context of the patient's overall condition. Non-invasive ultrasound-based methods, including critical care ultrasonography and the Venous Excess Ultrasound Score (VExUS), are emerging as promising alternatives, particularly in resource-limited settings. This review summarizes current methods for fluid management in severely burned patients, with a focus on the concepts of fluid responsiveness and fluid tolerance, and provides recommendations for clinical practice.

Accurately identifying surgical patients who will have an increase in stroke volume following fluid administration remains challenging when utilizing noninvasive bedside methods. This study aims to compare the value of using ultrasound to measure changes in corrected carotid artery flow time (ΔFTc) with that of using invasive measurements of stroke volume variation (ΔSVV) for assessing volume responsiveness in patients under general anesthesia and mechanical ventilation.