Exploration of the relationship between partial pressure of brain tissue oxygen and intracranial pressure.

Introduction: Partial pressure of brain tissue oxygen (PbtO2) has been shown to be a safe an effective monitoring modality to compliment intracranial pressure (ICP) monitoring. It is related to metabolic activity, disease severity and mortality. Research question: Understanding the complex relationship between PbtO2 and ICP for patients with traumatic brain injury will enable better clinical decision making beyond simple threshold treatment strategies. Material and methods: Patients with PbtO2 monitoring were identified from the BrainIT database, a multi-centre dataset, containing minute by minute PbtO2 and ICP readings. Missing data was imputed and a multi-level log-normal regression model with a compound symmetry correlation structure was built. This accounted for any increased correlation due to the repeated measurements. The model was adjusted for mean arterial pressure and the partial pressure of carbon dioxide. Non-linearity was assessed using analysis of deviance and trends using expected marginal means. Results: 11 subjects with over 82,000 readings were included. They had a median age of 38 (IQR: 37-47), 73% were male, a median length of stay of 11.8 (IQR: 6.6-19.7) days and a median extended Glasgow outcome scale of 7.00 (IQR: 5-8).There is a statistically significant (p < 0.001) non-linear effect of ICP on PbtO2. With an overall increase in PbtO2 of 5.2% (95% CI 4%-6.4%, p < 0.001) for a 10 mmHg increase in ICP below 22 mmHg and a decrease of 5.5% (95% CI 2.7%-8.3%, p=<0.001) in PbtO2 for a 10 mmHg increase in ICP above 22 mmHg. As well as a decrease of 40.9% (95% CI 2.3%-64.3%, p = 0.040) in PbtO2 per day in the intensive care unit. Discussion and conclusion: This model demonstrates that there is a significant non-linear relationship between ICP and PbtO2, however, this is a small heterogeneous cohort and further validation will be required.

Letter to editor: Brain tissue oxygen partial pressure monitoring and prognosis of patients with traumatic brain injury: a meta-analysis of published cases.

This critique evaluates a letter to the editor discussing the role of brain tissue oxygen partial pressure (PbtO2) monitoring in the prognosis of patients with traumatic brain injury (TBI). The meta-analysis aims to synthesize existing evidence, highlighting the potential of PbtO2 monitoring as an early indicator of cerebral hypoxia and its correlation with improved patient outcomes. Despite these promising findings, the analysis is constrained by significant methodological variability among the included studies, potential publication bias, and the practical challenges of implementing PbtO2 monitoring widely. The letter emphasizes the need for standardized protocols and further research to solidify the clinical utility of PbtO2 monitoring and integrate it with other monitoring strategies for comprehensive TBI management.

Validation of a Novel Noninvasive Technology to Estimate Blood Oxygen Saturation Using Green Light: Observational Study.

BACKGROUND: Pulse oximeters work within the red-infrared wavelengths. Therefore, these oximeters produce erratic results in dark-skinned subjects and in subjects with cold extremities. Pulse oximetry is routinely performed in patients with fever; however, an elevation in body temperature decreases the affinity of hemoglobin for oxygen, causing a drop in oxygen saturation or oxyhemoglobin concentrations. OBJECTIVE: We aimed to determine whether our new investigational device, the Shani device or SH1 (US Patent 11191460), detects a drop in oxygen saturation or a decrease in oxyhemoglobin concentrations. METHODS: An observational study (phase 1) was performed in two separate groups to validate measurements of hemoglobin and oxygen concentrations, including 39 participants recruited among current university students and staff aged 20-40 years. All volunteers completed baseline readings using the SH1 device and the commercially available Food and Drug Administration-approved pulse oximeter Masimo. SH1 uses two light-emitting diodes in which the emitted wavelengths match with absorption peaks of oxyhemoglobin (hemoglobin combined with oxygen) and deoxyhemoglobin (hemoglobin without oxygen or reduced hemoglobin). Total hemoglobin was calculated as the sum of oxyhemoglobin and deoxyhemoglobin. Subsequently, 16 subjects completed the "heat jacket study" and the others completed the "blood donation study." Masimo was consistently used on the finger for comparison. The melanin level was accounted for using the von Luschan skin color scale (VLS) and a specifically designed algorithm. We here focus on the results of the heat jacket study, in which the subject wore a double-layered heated jacket and pair of trousers including a network of polythene tubules along with an inlet and outlet. Warm water was circulated to increase the body temperature by 0.5-0.8 °C above the baseline body temperature. We expected a slight drop in oxyhemoglobin concentrations in the heating phase at the tissue level. RESULTS: The mean age of the participants was 24.1 (SD 0.8) years. The skin tone varied from 12 to 36 on the VLS, representing a uniform distribution with one-third of the participants having fair skin, brown skin, and dark skin, respectively. Using a specific algorithm and software, the reflection ratio for oxyhemoglobin was displayed on the screen of the device along with direct hemoglobin values. The SH1 device picked up more minor changes in oxyhemoglobin levels after a change in body temperature compared to the pulse oximeter, with a maximum drop in oxyhemoglobin concentration detected of 6.5% and 2.54%, respectively. CONCLUSIONS: Our new investigational device SH1 measures oxygen saturation at the tissue level by reflectance spectroscopy using green wavelengths. This device fared well regardless of skin color. This device can thus eliminate racial disparity in these key biomarker assessments. Moreover, since the light is shone on the wrist, SH1 can be readily miniaturized into a wearable device.

Cerebral fractional tissue oxygen extraction (cFTOE) during immediate fetal-to-neonatal transition: a systematic qualitative review of the literature.

Cerebral monitoring during immediate fetal-to-neonatal transition is of increasing interest. The cerebral fractional tissue oxygen extraction (cFTOE) is a useful parameter to gain insight in the balance between tissue oxygen delivery and consumption during this complex process. The aim of this study was to review the literature on cFTOE during the first 15 min immediately after birth. A systematic qualitative literature research was last performed on 23 November 2023 of PubMed and EMBASE with the following search terms: neonate, infant, newborn, transition, after birth, delivery room, NIRS, near-infrared spectroscopy, spectroscopy, cFTOE, cerebral fractional tissue oxygenation extraction, cerebral oxygenation, and fractional oxygen extraction. Additional published reports were identified through a manual search of references in retrieved articles and in review articles. The methodological quality of the included studies was assessed by predefined quality criteria. Only human studies with data of cFTOE in the first 15 min after birth were included. Accordingly, exclusion criteria were defined as no measurement of cFTOE or no measurement within the first 15 min after birth. Across all studies, a total of 3566 infants (2423 term, 1143 preterm infants) were analysed. Twenty-five studies were identified describing cFTOE within the first 15 min after birth. Four studies established reference ranges for cFTOE and another four studies focused on the effect of pre-/perinatal circumstances on cFTOE in the first 15 min after birth. Six studies investigated the course of cFTOE after transition in infants without complications. Eleven studies analysed different potentially influencing parameters on cFTOE during transition. CONCLUSION: This systematic review provides a comprehensive insight on cFTOE during uncomplicated transition as well as the influence of perinatal circumstances, respiratory, haemodynamic, neurological, and laboratory parameters in preterm and term infants. WHAT IS KNOWN: • The NIRS-measured cerebral fractional tissue oxygen extraction (cFTOE) is a useful parameter to estimate the balance between oxygen delivery and consumption. • During normal transition, the cFTOE decreases in the first minutes after birth and then remains at a stable plateau. WHAT IS NEW: • The cFTOE is a promising parameter that gives additional information on cerebral oxygenation and perfusion in preterm and term infants. • Several hemodynamic, metabolic, respiratory, and perinatal factors are identified, influencing the oxygen extraction of the newborn's brain after birth.

Multispectral Imaging-Based System for Detecting Tissue Oxygen Saturation With Wound Segmentation for Monitoring Wound Healing.

OBJECTIVE: Blood circulation is an important indicator of wound healing. In this study, a tissue oxygen saturation detecting (TOSD) system that is based on multispectral imaging (MSI) is proposed to quantify the degree of tissue oxygen saturation (StO2) in cutaneous tissues. METHODS: A wound segmentation algorithm is used to segment automatically wound and skin areas, eliminating the need for manual labeling and applying adaptive tissue optics. Animal experiments were conducted on six mice in which they were observed seven times, once every two days. The TOSD system illuminated cutaneous tissues with two wavelengths of light - red ([Formula: see text] nm) and near-infrared ([Formula: see text] nm), and StO2 levels were calculated using images that were captured using a monochrome camera. The wound segmentation algorithm using ResNet34-based U-Net was integrated with computer vision techniques to improve its performance. RESULTS: Animal experiments revealed that the wound segmentation algorithm achieved a Dice score of 93.49%. The StO2 levels that were determined using the TOSD system varied significantly among the phases of wound healing. Changes in StO2 levels were detected before laser speckle contrast imaging (LSCI) detected changes in blood flux. Moreover, statistical features that were extracted from the TOSD system and LSCI were utilized in principal component analysis (PCA) to visualize different wound healing phases. The average silhouette coefficients of the TOSD system with segmentation (ResNet34-based U-Net) and LSCI were 0.2890 and 0.0194, respectively. CONCLUSION: By detecting the StO2 levels of cutaneous tissues using the TOSD system with segmentation, the phases of wound healing were accurately distinguished. This method can support medical personnel in conducting precise wound assessments. Clinical and Translational Impact Statement-This study supports efforts in monitoring StO2 levels, wound segmentation, and wound healing phase classification to improve the efficiency and accuracy of preclinical research in the field.

Brain tissue oxygen plus intracranial pressure monitoring versus isolated intracranial pressure monitoring in patients with traumatic brain injury: an updated meta-analysis of randomized controlled trials.

BACKGROUND: Intracranial pressure (ICP) monitoring plays a key role in patients with traumatic brain injury (TBI), however, cerebral hypoxia can occur without intracranial hypertension. Aiming to improve neuroprotection in these patients, a possible alternative is the association of Brain Tissue Oxygen Pressure (PbtO2) monitoring, used to detect PbtO2 tension. METHOD: We systematically searched PubMed, Embase and Cochrane Central for RCTs comparing combined PbtO2 + ICP monitoring with ICP monitoring alone in patients with severe or moderate TBI. The outcomes analyzed were mortality at 6 months, favorable outcome (GOS ≥ 4 or GOSE ≥ 5) at 6 months, pulmonary events, cardiovascular events and sepsis rate. RESULTS: We included 4 RCTs in the analysis, totaling 505 patients. Combined PbtO2 + ICP monitoring was used in 241 (47.72%) patients. There was no significant difference between the groups in relation to favorable outcome at 6 months (RR 1.17; 95% CI 0.95-1.43; p = 0.134; I2 = 0%), mortality at 6 months (RR 0.82; 95% CI 0.57-1.18; p = 0.281; I2 = 34%), cardiovascular events (RR 1.75; 95% CI 0.86-3.52; p = 0.120; I2 = 0%) or sepsis (RR 0.75; 95% CI 0.25-2.22; p = 0.604; I2 = 0%). The risk of pulmonary events was significantly higher in the group with combined PbtO2 + ICP monitoring (RR 1.44; 95% CI 1.11-1.87; p = 0.006; I2 = 0%). CONCLUSIONS: Our findings suggest that combined PbtO2 + ICP monitoring does not change outcomes such as mortality, functional recovery, cardiovascular events or sepsis. Furthermore, we found a higher risk of pulmonary events in patients undergoing combined monitoring.

Brain tissue oxygen partial pressure monitoring and prognosis of patients with traumatic brain injury: a meta-analysis.

To assess whether monitoring brain tissue oxygen partial pressure (PbtO2) or employing intracranial pressure (ICP)/cerebral perfusion pressure (CCP)-guided management improves patient outcomes, including mortality, hospital length of stay (LOS), mean daily ICP and mean daily CCP during the intensive care unit(ICU)stay. We searched the Web of Science, EMBASE, PubMed, Cochrane Library, and MEDLINE databases until December 12, 2023. Prospective randomized controlled and cohort studies were included. A meta-analysis was performed for the primary outcome measure, mortality, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Eleven studies with a total of 37,492 patients were included. The mortality in the group with PbtO2 was 29.0% (odds ratio: 0.73;95% confidence interval [CI]:0.56-0.96; P = 0.03; I = 55%), demonstrating a significant benefit. The overall hospital LOS was longer in the PbtO2 group than that in the ICP/CPP group (mean difference:2.03; 95% CI:1.03-3.02; P<0.0001; I = 39%). The mean daily ICP in the PbtO2 monitoring group was lower than that in the ICP/CPP group (mean difference:-1.93; 95% CI: -3.61 to -0.24; P = 0.03; I = 41%). Moreover, PbtO2 monitoring did not improve the mean daily CPP (mean difference:2.43; 95%CI: -1.39 to 6.25;P = 0.21; I = 56%).Compared with ICP/CPP monitoring, PbtO2 monitoring reduced the mortality and the mean daily ICP in patients with severe traumatic brain injury; however, no significant effect was noted on the mean daily CPP. In contrast, ICP/CPP monitoring alone was associated with a short hospital stay.

Evaluation of the blood flow in reconstructed gastric tube and its relation to anastomosis leakage.

OBJECTIVES: Anastomotic leakage in esophageal cancer surgery may be reduced by evaluating the blood flow to the reconstructed organ, but quantitative evaluation of arterial and venous blood flow is difficult. This study aimed to quantitatively assess blood flow using a new technique, as well as determine the relationship between the blood flow in the gastric tube and anastomotic leakage using near-infrared spectroscopy. METHODS: This single-center, observational study included 50 patients aged 51-82 years who underwent radical esophagectomy with gastric tube reconstruction for esophageal cancer between June 2022 and January 2023. Regional tissue oxygen saturation was measured at the antrum (point X), the anastomotic point (point Z), and the midpoint between points X and Z (point Y) before and after gastric tube formation. These three points of oxygen saturation were investigated in relation to anastomotic leakage. RESULTS: When comparing the presence of leakage to its absence, regional tissue oxygen saturation at points X and Z after gastric tube formation was significantly lower (X: p = 0.03, Z: p = 0.02), with the decreasing rate significantly higher at point Z (p = 0.01). There was no significant difference in the decreasing rate of regional tissue oxygen saturation between points X and Y (X: p = 0.052, Y: p = 0.83). CONCLUSION: Regional tissue oxygen saturation levels may be useful for measuring blood flow and could be a predictor of anastomotic leakage.

Cerebral tissue oxygen desaturations and increased fractional oxygen extraction events vary by gestational age in preterm infants.

BACKGROUND AND OBJECTIVES: Cerebral tissue oxygen saturation (SctO2) and cerebral fractional tissue oxygen extraction (cFTOE) changes with GA in preterm infants. This study examines changes in frequency, duration, and severity of SctO2 desaturation and increased cFTOE with GA. STUDY DESIGN: The lower limit of normal SctO2, the event threshold, was calculated using a tolerance interval method with 95% confidence interval (CI) and 90% probability. Cerebral desaturation events were defined as: 1) a drop below event threshold for at least 30 s (s), 2) preceded by a period above the event threshold for at least 30s, and 3) followed by a period above the threshold for at least 60s. RESULTS: 86% of infants <28 wk experienced one or more SctO2 desaturation event compared to 57% in >28 wk, odds ratios (OR) 4.5 (CI:1.3-15.3, p = 0.016). The severity of SctO2 desaturation events decreases at a rate of 77.9 units per wk increase in GA (p < 0.001). 39.3% of infants <28 wk experienced one or more increased cFTOE events compared to 28.6% in >28 wk, OR 1.6 (CI:0.6-4.4, p = 0.35). The severity of increasing cFTOE events decreased by 69.7 units per wk increase in GA (p < 0.001). CONCLUSION: Cerebral tissue oxygen desaturation events decrease in frequency and severity with increasing GA. The severity of increased cFTOE episodes decrease with GA.

Treatment of hard-to-heal wounds in ischaemic lower extremities with a novel fish skin-derived matrix.

OBJECTIVE: To evaluate the efficacy of treatment of hard-to-heal wounds of patients with ischaemia of the lower extremities, and compare an omega-3 wound matrix product (Kerecis, Iceland) with a standard dressing. METHOD: A single-centre, prospective, randomised, controlled clinical trial of patients with hard-to-heal wounds following three weeks of standard care was undertaken. The ischaemic condition of the wound was confirmed as a decreased transcutaneous oxygen pressure (TcPO2) of <40mmHg. After randomising patients into either a case (omega-3 dressing) or a control group (standard dressing), the weekly decrease in wound area over 12 weeks and the number of patients that achieved complete wound closure were compared between the two groups. Patients with a TcPO2 of ≤32mmHg were taken for further analysis of their wound in a severe ischaemic context. RESULTS: A total of 28 patients were assigned to the case group and 22 patients to the control group. Over the course of 12 weeks, the wound area decreased more rapidly in the case group than the control group. Complete wound healing occurred in 82% of patients in the case group and 45% in the control group. Even in patients with a severe ischaemic wound with a TcPO2 value of <32 mmHg, wound area decreased more rapidly in the case group than the control group. The proportions of re-epithelialised area in the case and control groups were 80.24% and 57.44%, respectively. CONCLUSION: Considering the more rapid decrease in wound area and complete healing ratio in the case group, application of a fish skin-derived matrix for treating lower-extremity hard-to-heal wounds, especially with impaired vascularity, would appear to be a good treatment option.

Application of the Single Source-Detector Separation Algorithm in Wearable Neuroimaging Devices: A Step toward Miniaturized Biosensor for Hypoxia Detection.

Most currently available wearable devices to noninvasively detect hypoxia use the spatially resolved spectroscopy (SRS) method to calculate cerebral tissue oxygen saturation (StO2). This study applies the single source-detector separation (SSDS) algorithm to calculate StO2. Near-infrared spectroscopy (NIRS) data were collected from 26 healthy adult volunteers during a breath-holding task using a wearable NIRS device, which included two source-detector separations (SDSs). These data were used to derive oxyhemoglobin (HbO) change and StO2. In the group analysis, both HbO change and StO2 exhibited significant change during a breath-holding task. Specifically, they initially decreased to minimums at around 10 s and then steadily increased to maximums, which were significantly greater than baseline levels, at 25-30 s (p-HbO < 0.001 and p-StO2 < 0.05). However, at an individual level, the SRS method failed to detect changes in cerebral StO2 in response to a short breath-holding task. Furthermore, the SSDS algorithm is more robust than the SRS method in quantifying change in cerebral StO2 in response to a breath-holding task. In conclusion, these findings have demonstrated the potential use of the SSDS algorithm in developing a miniaturized wearable biosensor to monitor cerebral StO2 and detect cerebral hypoxia.

Chemical angioplasty vs. balloon plus chemical angioplasty for delayed cerebral ischemia: a pilot study of PbtO2 outcomes.

BACKGROUND: Delayed cerebral ischaemia (DCI) is a major cause of morbidity and mortality after aneurysmal subarachnoid haemorrhage (aSAH). Chemical angioplasty (CA) and transluminal balloon angioplasty (TBA) are used to treat patients with refractory vasospasm causing DCI. Multi-modal monitoring including brain tissue oxygenation (PbtO2) is routinely used at this centre for early detection and management of DCI following aSAH. In this single-centre pilot study, we are comparing these two treatment modalities and their effects on PbtO2. METHODS: Retrospective case series of patients with DCI who had PbtO2 monitoring as part of their multimodality monitoring and underwent either CA or TBA combined with CA. PbtO2 values were recorded from intra-parenchymal Raumedic NEUROVENT-PTO® probes. Data were continuously collected and downloaded as second-by-second data. Comparisons were made between pre-angioplasty PbtO2 and post-angioplasty PbtO2 median values (4 h before angioplasty, 4 h after and 12 h after). RESULTS: There were immediate significant improvements in PbtO2 at the start of intervention in both groups. PbtO2 then increased by 13 mmHg in the CA group and 15 mmHg in the TBA plus CA group in the first 4 h post-intervention. This improvement in PbtO2 was sustained for the TBA plus CA group but not the CA group. CONCLUSION: Combined balloon plus chemical angioplasty results in more sustained improvement in brain tissue oxygenation compared with chemical angioplasty alone. Our findings suggest that PbtO2 is a useful tool for monitoring the response to angioplasty in vasospasm.

Evaluation of cerebral autoregulation of oxygen by NIRS method during postnatal transition period in term and late preterm newborns without resuscitation requirement.

BACKGROUND: Pulse oximetry is commonly used to monitor arterial oxygen saturation and heart rate during the transition period and reference intervals have been determined. However, the effect of the change in arterial oxygen saturation on tissue oxygenation does not seem to be the same. So, a non-invasive method for monitoring cerebral or regional tissue oxygenation will be potentially useful for vulnerable infants. This study aims to evaluate the effectiveness of cerebral autoregulation in the first 10 min after delivery in term and late preterm newborns without resuscitation requirement. METHODS: Cerebral tissue oxygen saturation was measured in the first 10 min after birth with near-infrared spectroscopy (NIRS) from the left forehead. Peripheral oxygen saturation was measured with pulse oximetry from the right hand and cerebral fractional tissue oxygen extraction was calculated. RESULTS: Nineteen late preterms and 20 term infants were included in the study. There was no statistically significant difference between median cerebral tissue oxygen saturation and cerebral fractional tissue oxygen extraction values of late preterm and term infants (p < 0.001). There was a strong inverse relationship between cerebral tissue oxygen saturation and cerebral fractional tissue oxygen extraction (p < 0.001). CONCLUSIONS: In late preterm infants similar to term infants, arterial oxygen saturation and cerebral tissue oxygen saturation increased with time, but inverse reduction of cerebral fractional tissue oxygen extraction showed the presence of an active autoregulation in the brain. This can be interpreted as the ability of the brain to protect itself from hypoxia by regulating oxygen uptake during normal fetal-neonatal transition process. A larger scale multi-center randomized control trial is now needed to further inform practice.

Changes in regional tissue oxygen saturation values during the first week of life in stable preterm infants.

OBJECTIVES: Near infrared spectroscopy (NIRS) is a non-invasive method for monitoring regional tissue oxygen saturation (rSO2). The purpose of this study is to investigate the changes that occur in cerebral, splanchnic, and renal rSO2 and fractional tissue oxygen extraction (FTOE) in stable preterm infants in the first week of life. METHODS: Prospective observational study of infants born 30-34 weeks gestation at NYU Langone Health between November 2017 and November 2018. Cerebral, renal, and splanchnic rSO2 were monitored from 12 to 72 h of life, and at seven days. Subjects were divided into gestational age (GA) cohorts. Average rSO2, splanchnic cerebral oxygen ratio (SCOR), FTOE, and regional intra-subject variability was calculated at each location at five different time intervals: 0-12 h, 12-24 h, 24-48 h, 48-72 h, and one week of life. RESULTS: Twenty subjects were enrolled. The average cerebral rSO2 ranged from 76.8 to 92.8 %, renal rSO2 from 65.1 to 91.1 %, and splanchnic rSO2 from 36.1 to 76.3 %. The SCOR ranged from 0.45 to 0.94. The strongest correlation between the GA cohorts was in the cerebral region (R2=0.94) and weakest correlation was in the splanchnic region (R2=0.81). The FTOE increased in all three locations over time. Intra-subject variability was lowest in the cerebral region (1.3 % (±1.9)). CONCLUSIONS: The cerebral region showed the strongest correlation between GA cohorts and lowest intra-subject variability, making it the most suitable for clinical use when monitoring for tissue hypoxia. Further studies are needed to further examine rSO2 in preterm infants.

Effect of blood flow restriction and electrical muscle stimulation on human glycemic response to a glucose challenge.

PURPOSE: To determine whether reduced tissue oxygen availability through blood flow restriction (BFR) alone, or in combination with electrically induced muscle contractions, can improve glucose clearance after an acute glucose challenge. METHODS: In a randomized crossover design, 21 young participants (females: 12) were allocated to perform 1) electrical muscle stimulation (EMS), 2) BFR, 3) EMS + BFR or 4) no treatment (control). Participants completed each condition immediately preceding a 2 h oral glucose tolerance test (100 g). Primary analyses were performed on the glucose area under the curve (AUC) at time points 0-30, 30-120, and 0-120 min. Secondary analyses were performed on glycemic responses based on biological sex and estimated muscle phenotype. RESULTS: Compared to the control (322±25 mM∙min), the 0-30 min AUC was reduced following EMS (293±22 mM∙min, p = 0.0004), and EMS + BFR (298±36 mM∙min., p = 0.006), whereas BFR in isolation did not differ (306±30 mM∙min, p = 0.1). The 30-120 and 0-120 min glucose AUCs were similar across conditions. Based on effect size from the control conditions, our secondary analysis suggests different 0-30 min glycemic responses after EMS + BFR between females (dz = 0.206) vs. males (dz = 1.461) and/or slow (dz = 0.426) vs. fast (dz = 1.075) muscle phenotype. CONCLUSION: Reducing tissue oxygen availability with BFR did not augment the effects of EMS in the overall group; however, we provide preliminary data to suggest possible sex and/or muscle phenotypic responses in glycemic regulation with these modalities.

Biomarkers in the Severity of Necrotizing Enterocolitis in Preterm Infants: A Pilot Study.

Background: The occurrence of necrotizing enterocolitis (NEC) is a common and severe disease of the digestive system in neonates. This study aims to assess the value of the intestinal tissue oxygen saturation (rintSO2) combined with the levels of procalcitonin (PCT) and mean platelet volume (MPV) in predicting the severity of NEC in preterm infants. Methods: This experiment was a retrospective cohort study conducted in the Department of Pediatrics, Hongqi Hospital Affiliated to Mudanjiang Medical University between January 2017 and July 2022. Premature neonates with NEC were enrolled and divided into mild-moderate NEC group and severe NEC group according to Bell's stage. The general information data, rintSO2 and blood parameters such as the white blood cell (WBC) count, platelet count (PLT), PCT, MPV, red blood cell distribution width (RDW), hemoglobin (Hb), C-reactive protein (CRP) were compared between the two groups. Results: A total of 122 patients were enrolled, including 79 mild-moderate NEC and 43 severe NEC. The rintSO2 was lower in severe group than in mild-moderate group (P = 0.042), the PCT and MPV were both higher in severe group than in mild-moderate group (P = 0.048, P = 0.049). The results of logistic regression suggested that the rintSO2 (OR = 1.491, P = 0.003), PCT (OR = 3.071, P = 0.001) and MPV (OR = 4.027, P = 0.015) were independent predictive factors for severity of NEC. The area under the curve (AUC) of the rintSO2 combined with PCT and MPV showed good diagnostic ability in the severity of NEC. Conclusion: The rintSO2 combined with PCT and MPV may be considered as the early biomarkers in the severity of NEC and could help us to diagnose the case early with early treatment with better prognosis.

The Effect of Ciprofol on Postoperative Delirium in Elderly Patients Undergoing Thoracoscopic Surgery for Lung Cancer: A Prospective, Randomized, Controlled Trial.

Purpose: This study was conducted to assess whether ciprofol vs propofol could affect the incidence of postoperative delirium (POD) in elderly patients with lung cancer after thoracoscopic surgery. Patients and Methods: In this study, a total of 84 elderly patients undergoing thoracoscopic surgery for lung cancer were recruited and randomized into two groups to receive anesthesia with either ciprofol or propofol. The primary outcome was the incidence of POD within three days after surgery. Secondary outcomes included the Confusion Assessment Method (CAM) score, intraoperative indicators related to mean arterial pressure (MAP), and cerebral tissue oxygen saturation (SctO2). Moreover, MAP- and SctO2-related indicators associated with POD were analyzed. Results: The incidence of POD was 7.1% and 16.7%, respectively, in the ciprofol group and the propofol group (risk ratio [RR], 0.37; 95% confidence interval [CI], 0.07 to 2.03; risk difference [RD], -9.6%; 95% CI, -23.3% to 4.1%; p = 0.178). Compared with those in the propofol group, patients in the ciprofol group had lower CAM scores three days after surgery (13 (12, 15) vs 15 (14, 17); 12 (11, 13) vs 14 (13, 16); 12 (11, 12) vs 13 (12, 14), p<0.05). Besides, patients in the ciprofol group exhibited higher mean and minimum MAP (88.63 ± 6.7 vs 85 ± 8.3; 69.81 ± 9.59 vs 64.9 ± 9.43, p<0.05) and SctO2 (77.26 ± 3.96 vs 75.3 ± 4.49, 71.69 ± 4.51 vs 68.77 ± 6.46, p<0.05) and percentage of time for blood pressure stabilization (0.6 ± 0.14 vs 0.45 ± 0.14, p<0.05) than those in the propofol group. Furthermore, MAP and SctO2-related indicators were validated to correlate with POD. Conclusion: Anesthesia with ciprofol did not increase the incidence of POD compared with propofol. The results demonstrated that ciprofol could improve intraoperative MAP and SctO2 levels and diminish postoperative CAM scores.

Impact of Skin Pigmentation on Cerebral Regional Saturation of Oxygen Using Near-Infrared Spectroscopy: A Systematic Review.

OBJECTIVES: Near-infrared spectroscopy (NIRS) is used in critical care settings to measure regional cerebral tissue oxygenation (rSo2). However, the accuracy of such measurements has been questioned in darker-skinned individuals due to the confounding effects of light absorption by melanin. In this systematic review, we aim to synthesize the available evidence on the effect of skin pigmentation on rSo2 readings. DATA SOURCES: We systematically searched MEDLINE, Cochrane Database of Systematic Reviews, Embase, and Google Scholar from inception to July 1, 2023. STUDY SELECTION: In compliance with our PROSPERO registration (CRD42022347548), we selected articles comparing rSo2 measurements in adults either between racial groups or at different levels of skin pigmentation. Two independent reviewers conducted full-text reviews of all potentially relevant articles. DATA EXTRACTION: We extracted data on self-reported race or level of skin pigmentation and mean rSo2 values. DATA SYNTHESIS: Of the 11,495 unique records screened, two studies (n = 7,549) met our inclusion criteria for systematic review. Sun et al (2015) yielded significantly lower rSo2 values for African Americans compared with Caucasians, whereas Stannard et al (2021) found little difference between self-reported racial groups. This discrepancy is likely because Stannard et al (2021) used a NIRS platform which specifically purports to control for the effects of melanin. Several other studies that did not meet our inclusion criteria corroborated the notion that skin pigmentation results in lower rSo2 readings. CONCLUSIONS: Skin pigmentation likely results in attenuated rSo2 readings. However, the magnitude of this effect may depend on the specific NIRS platform used.

In vivo visualization of burn depth in skin tissue of rats using hemoglobin parameters estimated by diffuse reflectance spectral imaging.

Significance: Burn injuries represent a global public health problem that kills an estimated 180,000 people annually. Non-fatal burns result in prolonged hospitalization, disfigurement, and disability. The most common, convenient, and widely used method for assessing burn depth is physical or visual examination, but the accuracy of this method is reportedly poor (60% to 75%). Rapid, correct assessment of burn depth is very important for the optimal management and treatment of burn patients. New methods of burn depth assessment that are inexpensive, simple, rapid, non-contact, and non-invasive are therefore needed. Aim: The aim of this study was to propose an approach to visualize the spatial distribution of burn depth using hemoglobin parameters estimated from spectral diffuse reflectance imaging and to demonstrate the feasibility of the proposed approach for differentiating burn depth in a rat model of scald burn injury. Approach: The new approach to creating a spatial map of burn depth was based on canonical discriminant analysis (CDA) of total hemoglobin concentration, tissue oxygen saturation, and methemoglobin saturation as estimated from spectral diffuse reflectance images. Burns of three different degrees of severity were created in rat dorsal skin by 10-s exposure to water maintained at 70°C, 78°C, and 98°C, respectively. Spectral images for dorsal regions were acquired under anesthesia immediately after burn injury and at 24 h, 48 h, and 72 h after injury. Results: Most areas of images in the group with skin exposed to 70°C water and 98°C water were classified as 70°C burn and 98°C burn, respectively. In contrast, no significant difference between areas classified as 78°C burn and 98°C burn from 24 h to 72 h was evident in the group with skin exposed to 78°C water, suggesting that burn depth was heterogeneous. Conclusions: The proposed approach combining diffuse reflectance spectral imaging and CDA appears promising for differentiating 70°C burns from 78°C burns and 98°C burns, and 98°C burns from 70°C burns and 78°C burns at 24 to 72 h after burn injury in a rat model of scald burn injury.

Measurements of Electrodermal Activity, Tissue Oxygen Saturation, and Visual Analog Scale for Different Cuff Pressures.

The quantification of comfort in binding parts, essential human-machine interfaces (HMI) for the functioning of rehabilitation robots, is necessary to reduce physical strain on the user despite great achievements in their structure and control. This study aims to investigate the physiological impacts of binding parts by measuring electrodermal activity (EDA) and tissue oxygen saturation (StO2). In Experiment 1, EDA was measured from 13 healthy subjects under three different pressure conditions (10, 20, and 30 kPa) for 1 min using a pneumatic cuff on the right thigh. In Experiment 2, EDA and StO2 were measured from 10 healthy subjects for 5 min. To analyze the correlation between EDA parameters and the decrease in StO2, a survey using the visual analog scale (VAS) was conducted to assess the level of discomfort at each pressure. The EDA signal was decomposed into phasic and tonic components, and the EDA parameters were extracted from these two components. RM ANOVA and a post hoc paired t-test were used to determine significant differences in parameters as the pressure increased. The results showed that EDA parameters and the decrease in StO2 significantly increased with the pressure increase. Among the extracted parameters, the decrease in StO2 and the mean SCL proved to be effective indicators. Such analysis outcomes would be highly beneficial for studies focusing on the comfort assessment of the binding parts of rehabilitation robots.