Association between prehospital ROX index with 30-day mortality among septic shock.

PURPOSE: Respiratory dysfunction is one of the most frequent symptoms observed during sepsis reflecting hypoxemia and/or acidosis that may be assessed by the ROX index (ratio of oxygen saturation by pulse oximetry/fraction of inspired oxygen to respiratory rate). This study aimed to describe the relationship between the prehospital ROX index and 30-day mortality rate among septic shock patients cared for in the prehospital setting by a mobile intensive care unit (MICU). METHODS: From May 2016 to December 2021, 530 septic shock patients cared for by a prehospital MICU were retrospectively analysed. Initial ROX index value was calculated at the first contact with MICU. A Cox regression analysis after propensity score matching was performed to assess the relationship between 30-day mortality rate and a ROX index ≤ 10. RESULTS: Pulmonary, digestive and urinary sepsis were suspected among 43%, 25% and 17% patients, respectively. The 30-day overall mortality reached 31%. Cox regression analysis showed a significant association between 30-day mortality and a ROX index ≤ 10: adjusted hazard ratio of 1.54 [1.08-2.31], p < 0.05. CONCLUSIONS: During the prehospital stage of septic shock patients cared for by a MICU, ROX index is significantly associated with 30-day mortality. A prehospital ROX ≤ 10 value is associated with a 1.5-fold 30-day mortality rate increase. Prospective studies are needed to confirm the ability of prehospital ROX to predict sepsis outcome since the prehospital setting.

Relationship among muscle strength, muscle endurance, and skeletal muscle oxygenation dynamics during ramp incremental cycle exercise.

Peak oxygen uptake (VO2), evaluated as exercise tolerance, is a strong predictor of life prognosis regardless of health condition. Several previous studies have reported that peak VO2 is higher in those with a greater decrease in muscle oxygen saturation (SmO2) in the active muscles during incremental exercise. However, the skeletal muscle characteristics of individuals exhibiting a greater decrease in SmO2 during active muscle engagement in incremental exercise remain unclear. This study aimed to clarify the relationship among muscle strength, muscle endurance, and skeletal muscle oxygenation dynamics in active leg muscles during incremental exercise. Twenty-four healthy young men were included and categorized into the non-moderate-to-high muscular strength and endurance group (those with low leg muscle strength, endurance, or both; n = 11) and the moderate-to-high muscular strength and endurance group (those with both moderate-to-high leg muscle strength and endurance; n = 13). All participants underwent cardiopulmonary exercise testing combined with near-infrared spectroscopy to assess whole-body peak VO2 and the change in SmO2 at the lateral vastus lateralis from rest to each exercise stage as skeletal muscle oxygenation dynamics. A linear mixed-effects model, with the change in SmO2 from rest to each stage as the dependent variable, individual participants as random effects, and group and exercise load as fixed effects, revealed significant main effects for both group (P = 0.001) and exercise load (P < 0.001) as well as a significant interaction between the two factors (P < 0.001). Furthermore, multiple-comparison test results showed that the change in SmO2 from rest to 40%-100% peak VO2 was significantly higher in the moderate-to-high muscular strength and endurance group than in the non-moderate-to-high muscular strength and endurance group. Maintaining both muscle strength and endurance at moderate or higher levels contributes to high skeletal muscle oxygenation dynamics (i.e., greater decrease in SmO2) during moderate- or high-intensity exercise.

Non-Invasive Monitoring of Microvascular Oxygenation and Reactive Hyperemia using Hybrid, Near-Infrared Diffuse Optical Spectroscopy for Critical Care.

The detection of levels of impairment in microvascular oxygen consumption and reactive hyperemia is vital in critical care. However, there are no practical means for a robust and quantitative evaluation. This paper describes a protocol to evaluate these impairments using a hybrid near-infrared diffuse optical device. The device contains modules for near-infrared time-resolved and diffuse correlation spectroscopies and pulse-oximetry. These modules allow the non-invasive, continuous, and real-time measurement of the absolute, microvascular blood/tissue oxygen saturation (StO2) and the blood flow index (BFI) along with the peripheral arterial oxygen saturation (SpO2). This device uses an integrated, computer-controlled tourniquet system to execute a standardized protocol with optical data acquisition from the brachioradialis muscle. The standardized vascular occlusion test (VOT) takes care of the variations in the occlusion duration and pressure reported in the literature, while the automation minimizes inter-operator differences. The protocol we describe focuses on a 3-min occlusion period but the details described in this paper can readily be adapted to other durations and cuff pressures, as well as other muscles. The inclusion of an extended baseline and post-occlusion recovery period measurement allows the quantification of the baseline values for all the parameters and the blood/tissue deoxygenation rate that corresponds to the metabolic rate of oxygen consumption. Once the cuff is released, we characterize the tissue reoxygenation rate, magnitude, and duration of the hyperemic response in BFI and StO2. These latter parameters correspond to the quantification of the reactive hyperemia, which provides information about the endothelial function. Furthermore, the above-mentioned measurements of the absolute concentration of oxygenated and deoxygenated hemoglobin, BFI, the derived metabolic rate of oxygen consumption, StO2, and SpO2 provide a yet-to-be-explored rich data set that can exhibit disease severity, personalized therapeutics, and management interventions.

Longitudinal analysis of microcirculatory parameters in gingival tissues after tooth extraction in patients with different risk profiles for wound healing disorders - a pilot study.

OBJECTIVES: We aimed to establish a risk profile for intraoral wound healing disorders based on measurements of microcirculation in gingival tissues. MATERIALS AND METHODS: Oxygen saturation (SO2) and blood flow in gingival tissues were measured with tissue spectrometry and laser doppler spectroscopy in 37 patients before/after tooth extractions. Patients were assigned to four groups: anamnestically and periodontally healthy patients (n = 7), anamnestically healthy but suffering from periodontitis (n = 10), anamnestically healthy but smoking and suffering from periodontitis (n = 10) and suffering from diabetes and periodontitis (n = 10). Measurements were performed at three different time points: Baseline measurement (T0), one day post extractionem (p.e.) (T1) and seven days p.e. (T2). RESULTS: Baseline SO2 values were higher in control patients (p = .038). This effect was most evident in comparison to smokers suffering from periodontitis (p = .042), followed by diabetics suffering from periodontitis (p = .09). An opposite trend was seen for blood flow. Patients suffering from periodontitis demonstrated higher blood flow values (p = .012). Five patients, which belonged to the group of smokers suffering from periodontitis, showed clinically a delayed wound healing. CONCLUSION: Differences in SO2 and blood flow of gingival tissue could be detected in different groups of patients with existing periodontitis compared to control patients. CLINICAL RELEVANCE: Lower baseline SO2 values could be a warning signal for possible wound healing disorders after oral surgery.

The acute effect of inhaled nitric oxide on the exercise capacity of patients with advanced interstitial lung disease: a randomized controlled trial.

BACKGROUND: Inhaled nitric oxide (iNO) selectively acts on the pulmonary vasculature of ventilated lung tissue by reducing pulmonary vascular resistance and intrapulmonary shunt. This effect may reduce ventilation/perfusion mismatch and decrease pulmonary hypertension in patients with interstitial lung disease. METHODS: In a prospective, single-blinded, randomized, placebo-controlled trial, participants with advanced interstitial lung disease, underwent two separate six-minute walk tests (6MWT): one with iNO and the other with a placebo. The primary outcome measured the difference in meters between the distances covered in the two tests. Secondary outcomes included oxygen saturation levels, distance-saturation product, and Borg dyspnea score. A predefined subgroup analysis was conducted for patients with pulmonary hypertension. RESULTS: Overall, 44 patients were included in the final analysis. The 6MWT distance was similar for iNO treatment and placebo, median 362 m (IQR 265-409) vs 371 m (IQR 250-407), respectively (p = 0.29). Subgroup analysis for patients with pulmonary hypertension showed no difference in 6MWT distance with iNO and placebo, median 339 (256-402) vs 332 (238-403) for the iNO and placebo tests respectively (P=0.50). No correlation was observed between mean pulmonary artery pressure values and the change in 6MWT distance with iNO versus placebo (spearman correlation Coefficient 0.24, P=0.33). CONCLUSION: In patients with advanced interstitial lung disease, both with and without concurrent pulmonary hypertension, the administration of inhaled nitric oxide failed to elicit beneficial effects on the six-minute walk distance and oxygen saturation. The use of inhaled NO was found to be safe and did not lead to any serious side effects. TRIAL REGISTRATION: (NCT03873298, MOH_2018-04-24_002331).

Feasibility of continuous non-invasive delivery of oxygen monitoring in cardiac surgical patients: a proof-of-concept preliminary study.

PURPOSE: Oxygen delivery (DO2) and its monitoring are highlighted to aid postoperative goal directed therapy (GDT) to improve perioperative outcomes such as acute kidney injury (AKI) after high-risk cardiac surgeries associated with multiple morbidities and mortality. However, DO2 monitoring is neither routine nor done postoperatively, and current methods are invasive and only produce intermittent DO2 trends. Hence, we proposed a novel algorithm that simultaneously integrates cardiac output (CO), hemoglobin (Hb) and oxygen saturation (SpO2) from the Edwards Life Sciences ClearSight System® and Masimo SET Pulse CO-Oximetry® to produce a continuous, real-time DO2 trend. METHODS: Our algorithm was built systematically with 4 components - machine interface to draw data with PuTTY, data extraction with parsing, data synchronization, and real-time DO2 presentation using a graphic-user interface. Hb readings were validated. RESULTS: Our algorithm was implemented successfully in 93% (n = 57 out of 61) of our recruited cardiac surgical patients. DO2 trends and AKI were studied. CONCLUSION: We demonstrated a novel proof-of-concept and feasibility of continuous, real-time, non-invasive DO2 monitoring, with each patient serving as their own control. Our study also lays the foundation for future investigations aimed at identifying personalized critical DO2 thresholds and optimizing DO2 as an integral part of GDT to enhance outcomes in perioperative cardiac surgery.

Emergency Department SpO2/FiO2 Ratios Correlate with Mechanical Ventilation and Intensive Care Unit Requirements in COVID-19 Patients.

Background: Patients with coronavirus 2019 (COVID-19) are at high risk for respiratory dysfunction. The pulse oximetry/fraction of inspired oxygen (SpO2/FiO2) ratio is a non-invasive assessment of respiratory dysfunction substituted for the PaO2:FiO2 ratio in Sequential Organ Failure Assessment scoring. We hypothesized that emergency department (ED) SpO2/FiO2 ratios correlate with requirement for mechanical ventilation in COVID-19 patients. Our objective was to identify COVID-19 patients at greatest risk of requiring mechanical ventilation, using SpO2/FiO2 ratios. Methods: We performed a retrospective review of patients admitted with COVID-19 at two hospitals. Highest and lowest SpO2/FiO2 ratios (percent saturation/fraction of inspired O2) were calculated on admission. We performed chi-square, univariate, and multiple regression analysis to evaluate the relationship of admission SpO2/FiO2 ratios with requirement for mechanical ventilation and intensive care unit (ICU) care. Results: A total of 539 patients (46% female; 84% White), with a mean age 67.6 ± 18.6 years, met inclusion criteria. Patients who required mechanical ventilation during their hospital stay were statistically younger in age (P = 0.001), had a higher body mass index (P < .001), and there was a higher percentage of patients who were obese (P = 0.03) and morbidly obese (P < .001). Shortness of breath, cough, and fever were the most common presenting symptoms with a median temperature of 99°F. Average white blood count was higher in patients who required ventilation (P = <0.001). A highest obtained ED SpO2/FiO2 ratio of ≤300 was associated with a requirement for mechanical ventilation. A lowest obtained ED SpO2/FiO2 ratio of ≤300 was associated with a requirement for intensive care unit care. There was no statistically significant correlation between ED SpO2/FiO2 ratios >300 and mechanical ventilation or intensive care unit (ICU) requirement. Conclusion: The ED SpO2/FiO2 ratios correlated with mechanical ventilation and ICU requirements during hospitalization for COVID-19. These results support ED SpO2/FiO2 as a possible triage tool and predictor of hospital resource requirements for patients admitted with COVID-19. Further investigation is warranted.

Comparison of the vitality test with sensitivity tests in mature and immature teeth: clinical trial.

BACKGROUND: One of the most important steps in deciding on the treatment of a tooth is to determine the vitality and health status of the pulp. Since immature teeth innervation is not completed, the response to sensitivity tests may not yield definite results. Pulse oximetry (PO) which is considered as a vitality test, measures the arterial oxygen saturation (SpO2). This study aims to compare PO, electric pulp test (EPT) and cold test in mature and immature permanent teeth. METHODS: 20 immature and 20 mature permanent incisors of 6-12-year-old ASA1 children who did not use any analgesics, were included in the study. Pulp vitality of the teeth was determined by EPT, cold test and PO. An infant probe of PO device (CMS60D, Contec Medical Systems Co. Ltd, China) was used to determine the SpO2 of the teeth. The SpO2 level is controlled on the patient's finger by a children's probe and an infant probe of PO. Shapiro-Wilk, Spearman rank correlation test and Kruskal-Wallis test/Dunn post-hoc analysis were used for statistical comparisons. RESULTS: There was no significant correlation between finger SpO2 and the mature/immature teeth SpO2 (r=-0.026, r = 0.253). Arterial oxygen saturation values in the immature teeth were significantly higher than in the mature teeth (p = 0.002). There was a high correlation between the vitality response of the EPT, cold test and PO. CONCLUSIONS: Pulse oximetry can be used as an effective vitality test compared to sensitivity tests in both immature and mature permanent incisors.

Oxygen therapy for exercise capacity in fibrotic interstitial lung disease: A systematic review and meta-analysis of randomised controlled trials.

BACKGROUND: Fibrotic interstitial lung disease (fILD) is characterised primarily by impaired lung function and quality of life. The present study investigated whether oxygen therapy could improve exercise capacity among patients with fILD. METHODS: Previously published randomised controlled trials (RCTs) were surveyed. A systematic review and meta-analysis was conducted to evaluate the effectiveness of oxygen therapy in improving the exertional capacity of patients with fILD. The primary outcome was peripheral oxygen saturation (SpO2) during exercise. The effects of oxygen therapy on fatigue, dyspnoea, heart rate, and exercise duration or distance were also analysed. RESULTS: Fourteen RCTs involving 370 patients were included. Oxygen therapy improved SpO2 during exercise (mean difference, MD = 6.26 %), exercise duration (MD = 122.15 s), fatigue (standard mean difference, SMD = -0.30), and dyspnoea (MD = -0.75 Borg score units). High-flow oxygen systems tended to be more effective than low-flow systems in improving exercising SpO2, duration, fatigue, dyspnoea, and heart rate. High-flow nasal cannulas (HFNCs) yielded better outcomes regarding SpO2 and fatigue than did high-flow Venturi masks (MD = 1.60 % and MD = -1.19 Borg score units, respectively). No major adverse events were reported. CONCLUSION: The evidence from RCTs supports the short-term use of oxygen supplementation to improve SpO2, exercise capacity, fatigue, and dyspnoea among patients with fILD. Further analyses demonstrates that HFNCs yield more favourable outcomes, yet not reaching statistical significance except for improving SpO2 and fatigue. However, the long-term effects of oxygen therapy on quality of life and mortality remain unclear.

Quantifying changes in oxygen saturation of the internal jugular vein in vivo using deep neural networks and subject-specific three-dimensional Monte Carlo models.

Central venous oxygen saturation (ScvO2) is an important parameter for assessing global oxygen usage and guiding clinical interventions. However, measuring ScvO2 requires invasive catheterization. As an alternative, we aim to noninvasively and continuously measure changes in oxygen saturation of the internal jugular vein (SijvO2) by a multi-channel near-infrared spectroscopy system. The relation between the measured reflectance and changes in SijvO2 is modeled by Monte Carlo simulations and used to build a prediction model using deep neural networks (DNNs). The prediction model is tested with simulated data to show robustness to individual variations in tissue optical properties. The proposed technique is promising to provide a noninvasive tool for monitoring the stability of brain oxygenation in broad patient populations.

Physiologic Determinants of Near-Infrared Spectroscopy-Derived Cerebral and Tissue Oxygen Saturation Measurements in Critically Ill Patients.

OBJECTIVES: Near-infrared spectroscopy (NIRS) is a potentially valuable modality to monitor the adequacy of oxygen delivery to the brain and other tissues in critically ill patients, but little is known about the physiologic determinants of NIRS-derived tissue oxygen saturations. The purpose of this study was to assess the contribution of routinely measured physiologic parameters to tissue oxygen saturation measured by NIRS. DESIGN: An observational sub-study of patients enrolled in the Role of Active Deresuscitation After Resuscitation-2 (RADAR-2) randomized feasibility trial. SETTING: Two ICUs in the United Kingdom. PATIENTS: Patients were recruited for the RADAR-2 study, which compared a conservative approach to fluid therapy and deresuscitation with usual care. Those included in this sub-study underwent continuous NIRS monitoring of cerebral oxygen saturations (SctO2) and quadriceps muscle tissue saturations (SmtO2). INTERVENTION: Synchronized and continuous mean arterial pressure (MAP), heart rate (HR), and pulse oximetry (oxygen saturation, Spo2) measurements were recorded alongside NIRS data. Arterial Paco2, Pao2, and hemoglobin concentration were recorded 12 hourly. Linear mixed effect models were used to investigate the association between these physiologic variables and cerebral and muscle tissue oxygen saturations. MEASUREMENTS AND MAIN RESULTS: Sixty-six patients were included in the analysis. Linear mixed models demonstrated that Paco2, Spo2, MAP, and HR were weakly associated with SctO2 but only explained 7.1% of the total variation. Spo2 and MAP were associated with SmtO2, but together only explained 0.8% of its total variation. The remaining variability was predominantly accounted for by between-subject differences. CONCLUSIONS: Our findings demonstrated that only a small proportion of variability in NIRS-derived cerebral and tissue oximetry measurements could be explained by routinely measured physiologic variables. We conclude that for NIRS to be a useful monitoring modality in critical care, considerable further research is required to understand physiologic determinants and prognostic significance.

Association between pediatric postoperative delirium and regional cerebral oxygen saturation: a prospective observational study.

BACKGROUND: Postoperative delirium (POD) represents a prevalent and noteworthy complication in the context of pediatric surgical interventions. In recent times, a hypothesis has emerged positing that cerebral ischemia and regional cerebral oxygen desaturation might serve as potential catalysts in the pathogenesis of POD. The primary aim of this study was to methodically examine the potential relationship between POD and regional cerebral oxygen saturation (rSO2) and to assess the predictive and evaluative utility of rSO2 in the context of POD. METHODS: This prospective observational study was conducted at the Children's Hospital, Zhejiang University School of Medicine, Zhejiang, China, spanning the period from November 2020 to March 2021. The research cohort comprised children undergoing surgical procedures within this clinical setting. To measure rSO2 dynamics, cerebral near-infrared spectroscopy (NIRS) was used to monitor rSO2 levels both before and after surgery. In addition, POD was assessed in the paediatric patients according to the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM-5) criteria. The analysis of the association between the rSO2 index and the incidence of POD was carried out through the application of either the independent samples t-test or the nonparametric rank-sum test. To ascertain the threshold value of the adjusted rSO2 index for predictive and evaluative purposes regarding POD in the pediatric population, the Receiver Operating Characteristics (ROC) curve was employed. RESULTS: A total of 211 cases were included in this study, of which 61 (28.9%) developed POD. Participants suffering delirium had lower preoperative rSO2mean, lower preoperative rSO2min, and lower postoperative rSO2min, higher ∆rSO2mean, higher amount of ∆rSO2mean, lower ∆rSO2min (P < 0.05). Preoperative rSO2mean (AUC = 0.716, 95%CI 0.642-0.790), ∆rSO2mean (AUC = 0.694, 95%CI 0.614-0.774), amount of ∆rSO2mean (AUC = 0.649, 95%CI 0.564-0.734), preoperative rSO2min (AUC = 0.702, 96%CI 0.628-0.777), postoperative rSO2min (AUC = 0.717, 95%CI 0.647-0.787), and ∆rSO2min (AUC = 0.714, 95%CI 0.638-0.790) performed well in sensitivity and specificity, and the best threshold were 62.05%, 1.27%, 2.41%, 55.68%, 57.36%, 1.29%. CONCLUSIONS: There is a close relationship between pediatric POD and rSO2. rSO2 could be used as an effective predictor of pediatric POD. It might be helpful to measure rSO2 with NIRS for early recognizing POD and making it possible for early intervention.

Application of intranasal dexmedetomidine in magnetic resonance imaging of preterm infants: The ED50, efficacy and safety analysis.

BACKGROUND: Infants undergoing magnetic resonance imaging (MRI) often require pharmacological sedation. Dexmedetomidine serves as a novel sedative agent that induces a unique unconsciousness similar to natural sleep, and therefore has currently been used as the first choice for sedation in infants and young children. OBJECTIVE: To determine the 50% effective dose (ED50) and 95% confidence interval (95%CI) of intranasal dexmedetomidine for MRI in preterm and term infants, and to observe the incidence of adverse events. To explore whether there were differences in ED50 and 95%CI, heart rate (HR) and blood oxygen saturation (SpO2), the induction time and wake-up time and the incidence of adverse events between the 2 groups, so as to provide guidance for clinical safe medication for the meanwhile. METHODS: A total of 68 infants were prospectively recruited for MRI examination under drug sedation (1 week ≤ age ≤ 23 weeks or weight ≤ 5kg). The children were divided into 2 groups according to whether they had preterm birth experience (Preterm group, Atterm group). The Dixon up-and-down method was used to explore ED50. The basic vital signs of the 2 groups were recorded, and the heart rate and SpO2 were recorded every 5 minutes until the infants were discharged from the hospital. The induction time, wake-up time and adverse events were recorded. RESULTS: The ED50 (95%CI) of intranasal dexmedetomidine in the Preterm group and the Atterm group were 2.23 (2.03-2.66) µg/kg and 2.64 (2.49-2.83) µg/kg, respectively (P < .05). the wake-up time was longer in Preterm group (98.00min) than in Atterm group (81.00 min) (P < .05), the incidence of bradycardia in Preterm group was 3/33, which was higher than that in Atterm group (1/35). There was no difference in the induction time between the 2 groups (P > .05), and there was no significant difference in other adverse events. CONCLUSIONS: Intranasal dexmedetomidine can be safely used for sedation in preterm infants undergoing MRI. Compared with term infants, preterm infants have a lower dose of dexmedetomidine, a higher incidence of bradycardia, and a longer weak-up time.

Physiologic oxygen responses to smoking opioids: an observational study using continuous pulse oximetry at overdose prevention services in British Columbia, Canada.

BACKGROUND: In British Columbia, Canada, smoking is the most common modality of drug use among people who die of opioid toxicity. We aimed to assess oxygen saturation (SpO2) while people smoked opioids during a pilot study that introduced continuous pulse oximetry at overdose prevention services (OPS) sites. METHODS: This was an observational cohort study, using a participatory design. We implemented our monitoring protocol from March to August 2021 at four OPS. We included adults (≥ 18 years) presenting to smoke opioids. A sensor taped to participants' fingers transmitted real-time SpO2 readings to a remote monitor viewed by OPS staff. Peer researchers collected baseline data and observed the timing of participants' inhalations. We analyzed SpO2 on a per-event basis. In mixed-effects logistic regression models, drop in minimum SpO2 ≤ 90% in the current minute was our main outcome variable. Inhalation in that same minute was our main predictor. We also examined inhalation in the previous minute, cumulative inhalations, inhalation rate, demographics, co-morbidities, and substance use variables. RESULTS: We recorded 599 smoking events; 72.8% (436/599) had analyzable SpO2 data. Participants' mean age was 38.6 years (SD 11.3 years) and 73.1% were male. SpO2 was highly variable within and between individuals. Drop in SpO2 ≤ 90% was not significantly associated with inhalation in that same minute (OR: 1.2 [0.8-1.78], p = 0.261) or inhalation rate (OR 0.47 [0.20-1.10], p = 0.082). There was an association of SpO2 drop with six cumulative inhalations (OR 3.38 [1.04-11.03], p = 0.043); this was not maintained ≥ 7 inhalations. Demographics, co-morbidities, and drug use variables were non-contributory. CONCLUSIONS: Continuous pulse oximetry SpO2 monitoring is a safe adjunct to monitoring people who smoke opioids at OPS. Our data reflect challenges of real-world monitoring, indicating that greater supports are needed for frontline responders at OPS. Inconsistent association between inhalations and SpO2 suggests that complex factors (e.g., inhalation depth/duration, opioid tolerance, drug use setting) contribute to hypoxemia and overdose risk while people smoke opioids.

[Effect of transnasal humidified rapid insufflation ventilatory exchange on cerebral oxygen saturation during induction of general anesthesia in patients undergoing traumatic brain injury emergency surgery].

OBJECTIVE: To evaluate the effect of transnasal humidified rapid insufflation ventilatory exchange (THRIVE) on regional cerebral oxygen saturation (rScO2) during induction of general anesthesia in patients undergoing traumatic brain injury (TBI) emergency surgery. METHODS: A prospective randomized controlled trial was conducted. The TBI emergency general anesthesia patients who underwent intracranial hematoma removal surgery at the Northern Jiangsu People's Hospital from January to July in 2023 were enrolled. The patients were divided into a conventional mask ventilation group and a THRIVE group using a random number table method. The patients in the conventional mask ventilation group were anesthetized and induced to pre oxygenate without positive pressure ventilation in the front mask for 10 minutes, with an oxygen flow rate of 8 L/min and an fraction of inspired oxygen (FiO2) of 1.00. After anesthesia induction for about 90 s, tracheal intubation was performed after the muscle relaxant took effect (patient's jaw muscle was relaxed). The patients in the THRIVE group were pre oxygenated with THRIVE for 10 minutes, with an oxygen flow rate of 30 L/min and a FiO2 of 1.00. During anesthesia induction, the oxygen flow rate was increased to 50 L/min, and anesthesia induction medication was used. The lower jaw of patient was supported with both hands to maintain airway patency, and the patient's mouth was kept closed throughout the process. After the muscle relaxant took effect (the patient's jaw muscle was relaxed), tracheal intubation was performed. At the time of patient entering the operating room, 10 minutes of pre oxygenation, and immediately after successful intubation, rScO2 was measured on the surgical and non-surgical sides. At the same time, ultrasound was used to measure the cross-sectional area (CSA) of the gastric antrum and arterial blood gas analysis was performed. The partial pressure of end-tidal carbon dioxide (PETCO2) during the first mechanical ventilation after successful tracheal intubation, the incidence of hypoxemia [pulse oxygen saturation (SpO2) < 0.95] during tracheal intubation, as well as prognostic indicators such as the length of intensive care unit (ICU) stay, total length of hospital stay, and Glasgow outcome scale (GOS) score at discharge were recorded. RESULTS: During the study period, a total of 70 TBI patients underwent emergency general anesthesia surgery, of which 2 patients died postoperatively, 2 patients were unable to cooperate with closed mouth breathing, and 3 patients had poor ultrasound image acquisition in the gastric antrum, all of whom were excluded. A total of 63 patients were ultimately enrolled, including 32 in the conventional mask ventilation group and 31 in the THRIVE group. There were no statistically significant differences in gender, age, body mass index (BMI), American Society of Anesthesiologists (ASA) classification, Glasgow coma scale (GCS) score, optic nerve sheath diameter (ONSD), baseline vital signs, fasting situation, anesthesia time, surgical time, and intraoperative blood loss between the patients in the two groups, indicating comparability. When entering the operating room, there was no statistically significant difference in rScO2 on the surgical and non-surgical sides, and blood gas analysis indexes arterial partial pressure of oxygen (PaO2) and arterial partial pressure of carbon dioxide (PaCO2) between the patients in the two groups. When pre oxygenated for 10 minutes, both the surgical and non-surgical sides rScO2 levels in the THRIVE group were significantly higher than those in the conventional mask ventilation group (surgical side: 0.709±0.036 vs. 0.636±0.028, non-surgical side: 0.791±0.016 vs. 0.712±0.027, both P < 0.01), and the PaO2 was significantly increased [mmHg (1 mmHg ≈ 0.133 kPa): 450.23±60.99 vs. 264.88±49.33, P < 0.01], PaCO2 was significantly reduced (mmHg: 37.81±3.65 vs. 43.59±3.76, P < 0.01), and the advantage continues tilled immediately after successful intubation. There was no statistically significant difference in CSA at each time point of ultrasound examination between the two groups. Compared with the conventional mask ventilation group, the patients in the THRIVE group showed a significant decrease in PETCO2 during the first mechanical ventilation after successful tracheal intubation (mmHg: 43.10±2.66 vs. 49.22±3.31, P < 0.01), and the incidence of hypoxemia during tracheal intubation was also significantly reduced [0% (0/31) vs. 28.12% (9/32), P < 0.01]. In terms of prognostic indicators, there was no statistically significant difference in the length of ICU stay and total length of hospital stay between the patients in the conventional mask ventilation group and the THRIVE group [length of ICU stay (days): 10 (9, 10) vs. 10 (9, 11), total length of hospital stay (days): 28.00 (26.00, 28.75) vs. 28.00 (27.00, 29.00), both P > 0.05]. However, the proportion of patients in the THRIVE group with a good prognosis at discharge (GOS score > 3) was significantly higher than that in the conventional mask ventilation group [35.5% (11/31) vs. 12.5% (4/32), P < 0.05]. CONCLUSIONS: THRIVE can significantly increase rScO2 during anesthesia induction in TBI emergency surgery patients and improve their neurological function prognosis.

BOLD: Blood-gas and Oximetry Linked Dataset.

Pulse oximeters measure peripheral arterial oxygen saturation (SpO2) noninvasively, while the gold standard (SaO2) involves arterial blood gas measurement. There are known racial and ethnic disparities in their performance. BOLD is a dataset that aims to underscore the importance of addressing biases in pulse oximetry accuracy, which disproportionately affect darker-skinned patients. The dataset was created by harmonizing three Electronic Health Record databases (MIMIC-III, MIMIC-IV, eICU-CRD) comprising Intensive Care Unit stays of US patients. Paired SpO2 and SaO2 measurements were time-aligned and combined with various other sociodemographic and parameters to provide a detailed representation of each patient. BOLD includes 49,099 paired measurements, within a 5-minute window and with oxygen saturation levels between 70-100%. Minority racial and ethnic groups account for ~25% of the data - a proportion seldom achieved in previous studies. The codebase is publicly available. Given the prevalent use of pulse oximeters in the hospital and at home, we hope that BOLD will be leveraged to develop debiasing algorithms that can result in more equitable healthcare solutions.

[Research progress of diagnostic and therapeutic value of carbon dioxide-derived indicators in patients with sepsis].

Effectively assessing oxygen delivery and demand is one of the key targets for fluid resuscitation in sepsis. Clinical signs and symptoms, blood lactic acid levels, and mixed venous oxygen saturation (SvO2) or central venous oxygen saturation (ScvO2) all have their limitations. In recent years, these limitations have been overcome through the use of derived indicators from carbon dioxide (CO2) such as mixed veno-arterial carbon dioxide partial pressure difference (Pv-aCO2, PCO2 gap, or ΔPCO2), the ratio of mixed veno-arterial carbon dioxide partial pressure difference to arterial-mixed venous oxygen content difference (Pv-aCO2/Ca-vO2). Pv-aCO2, PCO2 gap or ΔPCO2 is not a purely anaerobic metabolism indicator as it is influenced by oxygen consumption. However, it reliably indicates whether blood flow is sufficient to carry CO2 from peripheral tissues to the lungs for clearance, thus reflecting the adequacy of cardiac output and metabolism. The Pv-aCO2/Ca-vO2 may serve as a marker of hypoxia. SvO2 and ScvO2 represent venous oxygen saturation, reflecting tissue oxygen utilization. When oxygen delivery decreases but tissues still require more oxygen, oxygen extraction rate usually increases to meet tissue demands, resulting in decreased SvO2 and ScvO2. But in some cases, even if the oxygen delivery rate and tissue utilization rate of oxygen are reduced, it may still lead to a decrease in SvO2 and ScvO2. Sepsis is a classic example where tissue oxygen utilization decreases due to factors such as microcirculatory dysfunction, even when oxygen delivery is sufficient, leading to decrease in SvO2 and ScvO2. Additionally, the solubility of CO2 in plasma is approximately 20 times that of oxygen. Therefore, during sepsis or septic shock, derived variables of CO2 may serve as sensitive markers for monitoring tissue perfusion and microcirculatory hemodynamics. Its main advantage over blood lactic acid is its ability to rapidly change and provide real-time monitoring of tissue hypoxia. This review aims to demonstrate the principles of CO2-derived variables in sepsis, assess the available techniques for evaluating CO2-derived variables during the sepsis process, and discuss their clinical relevance.

Assessing hypoxic respiratory failure in mechanically ventilated neonates: A comparative study of oxygen saturation index and oxygenation index.

OBJECTIVE: To investigate the correlation between oxygen saturation index (OSI) and oxygenation index (OI) for evaluating the blood oxygenation status in neonates with respiratory failure requiring mechanical ventilation support and to assess the predictive capability of OSI in determining clinically relevant OI cutoffs. METHODS: A prospective study was conducted on neonates who received invasive mechanical ventilation at the neonatal intensive care unit of tertiary hospital in Vietnam. Bland-Altman analysis was utilized to evaluate the agreement between OSI and OI. RESULTS: A total of 123 neonates, including both term and preterm infants, were included in the study. A high agreement rate of 94.3% within the 95% limits of agreement (between OI and OSI), with a narrow similarity value of 3.3 (95% CI: -5.1 to 11.8) and high correlation coefficient (r = 0.791, p<0.001) was observed. The OSI cut-off value for predicting an OI of >15 was determined to be 7.45, with a sensitivity of 100% and a specificity of 87.4% (AUC 0.955; 95% CI: 0.922-0.989, p < 0.05). Similarly, an OSI cutoff value of 9.9 corresponded to an OI of 25, displaying a sensitivity of 100% and specificity of 87.4% (AUC 0.92). The receiver operating characteristic (ROC) curves for OSI exhibited statistically significant results (p < 0.05). CONCLUSION: The findings demonstrate a strong correlation between OSI and OI in neonates with respiratory failure. Furthermore, OSI, as a non-invasive method, can serve as a substitute for OI to evaluate the severity of hypoxic respiratory failure and lung injury in neonates.

The effects of on-pump and off-pump coronary artery bypass surgery on oxidative stress and cerebral oxygenation: a prospective observational study.

Background/aim: In this prospective observational study, our goal was to investigate the relationship between serum levels of oxidative stress (OS) parameters and regional cerebral oxygen saturation (rSO2) in addition to evaluating postoperative clinical outcomes among patients undergoing coronary artery bypass graft surgery (CABG). Materials and methods: This study comprised 64 adult patients undergoing elective CABG (on-pump [n = 48] and off-pump [n = 16]) procedures. Serum OS levels and rSO2 values were measured intraoperatively at three specific time points: T1 (after induction), T2 (15 min before aortic cross-clamp removal or the final distal anastomosis), and T3 (15 min after aortic cross-clamp removal or the last distal anastomosis). Results: Serum OS and lactate values demonstrated higher levels at T2 and T3 (p < 0.001), while rSO2 values were lower at T2 (p = 0.024) in the on-pump CABG group compared to the off-pump CABG group. The rSO2 values at T2 exhibited a negative correlation with OS parameters, lactate levels at T2 and T3, aortic clamp time, postoperative mechanical ventilation time, and intensive care unit stay length. In the multivariate linear regression analysis (R2 = 0.181, p = 0.001), lactate values at T2 emerged as the sole factor affecting the OS index at T2 (t = 2.843, p = 0.006). Conclusion: In our study, we observed elevated OS values and relatively low rSO2 values during on-pump CABG procedures, with rSO2 showing an association with increased OS parameters. Close monitoring of the OS response level and rSO2 during CABG could potentially enhance postoperative clinical outcomes.

Analysis of modified ilib therapy in patients submitted to plastic surgery.

The sample comprised 44 volunteers who had undergone some surgical procedure and were equally divided into four groups. G1 started the therapy 24 h after the surgical procedure with the device off. G2 followed the same time pattern, 24 h, but with the device turned on. G3 and G4 started therapy three days after the surgical procedure; in G3, the device was turned off, and in G4, the device remained on during therapy; each session lasted 30 min, using 660 nm (red), energy 180 J. For all groups, the therapy started with daily use for seven days and followed the interval use of three times a week until completed 21 days. The revaluation was performed after 7 and 21 days. The results found show changes in HR at rest, systolic and diastolic BP, and in peripheral oxygen saturation, which showed a significant difference in the groups that used on-therapy (p < 0.05). In the MCGILL Scale evaluation, the mean total score showed a more accentuated drop in the groups that used ILIB, (p < 0.05). ILIB may have prevented a more significant evolution of firosis levels; however, no changes were observed in the evaluation of sleep and anxiety. The application of the ILIB in patients undergoing plastic surgery was supported in terms of hemodynamics and pain; in addition, starting the ILIB application 24 h after the procedure proved to be more advantageous.