Regional Tissue Oxygen Saturation Research Articles

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

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. This single-center, observational study included 50 patients aged 51-82years 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. 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). Regional tissue oxygen saturation levels may be useful for measuring blood flow and could be a predictor of anastomotic leakage.

Predictive role of regional thigh tissue oxygen saturation monitoring during cardiopulmonary bypass in lung injury after cardiac surgery.

Acute respiratory distress syndrome (ARDS) is a serious complication following cardiac surgery mainly associated with the use of cardiopulmonary bypass (CPB), which could increase the risk of mortality and morbidity. This study investigated the association of regional oxygen saturation (rSO2) during CPB with postoperative outcomes, including respiratory function. Patients who underwent cardiac surgery with CPB from 2015 to 2019 were included. Near-infrared spectroscopy was used to monitor rSO2 at the forehead, abdomen, and thighs throughout the surgery. Postoperative markers associated with CPB were assessed for correlations with PaO2/FiO2 (P/F) ratios at intensive care unit (ICU) admission. Postoperative lung injury (LI) was defined as moderate or severe ARDS based on the Berlin criteria, and its incidence was 29.9% (20/67). On multiple regression analysis, the following were associated with P/F ratios at ICU admission: vasoactive-inotropic scores at CPB induction (P = 0.03), thigh rSO2 values during CPB (P = 0.04), and body surface area (P < 0.001). A thigh rSO2 of 71% during CPB was significantly predictive of postoperative LI with an area under the curve of 0.71 (P = 0.03), sensitivity of 0.70, and specificity of 0.68. Patients with postoperative LI had longer ventilation time and ICU stays. Thigh rSO2 values during CPB were a potential predictor of postoperative pulmonary outcomes.

Decreased Intraoperative Renal Tissue Oxygenation after Cardiopulmonary Bypass Predicts Cardiac Surgery-Associated Acute Kidney Injury in Neonates.

(1) Background: Near-infrared spectroscopy (NIRS) is a noninvasive tool frequently used during cardiac surgery and postoperatively in the cardiac intensive care unit to monitor regional tissue oxygen saturation. A relationship between trends of intraoperative renal oxygenation and the risk of developing cardiac surgery-associated acute kidney injury (AKI) post-operatively has not yet been established in the neonatal population. The objective of this study is to evaluate the relationship of cerebral and renal oxygenation during cardiopulmonary bypass with cardiac surgery-associated AKI in the first 72 h post-operation in neonates < 30 days of age. (2) Methods: A prospective cohort study at a tertiary care children's hospital was performed. Renal and cerebral oxygenation measured were collected intraoperatively from neonates < 30 days of age who underwent cardiopulmonary bypass for the correction of congenital heart disease. AKI was defined accordance with the Kidney Disease: Improving Global Outcomes criteria modified for neonates. Variables were compared between groups. (3) Results: 32 neonates with 35 cardiopulmonary bypass cases were included. AKI was diagnosed in 60% of cases. Intra-operative renal oxygenation, both on- and off-bypass, did not differ among the three AKI groups (p > 0.19). Renal oxygenation after coming off, but not during, cardiopulmonary bypass steadily decreased with increasing levels of AKI (Jonckheere's test, one-sided p = 0.024). (4) Conclusions: Renal oxygenation decreased in proportion to AKI severity after coming off, but not during, cardiopulmonary bypass.

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

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. Prospective observational study of infants born 30-34weeks 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, andatseven 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. Twenty subjects were enrolled. The average cerebral rSO2 ranged from 76.8 to 92.8 %, renal rSO2 from 65.1 to91.1 %, 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)). The cerebral region showed the strongest correlation between GA cohorts and lowest intra-subject variability, making it the most suitable for clinical use whenmonitoring for tissue hypoxia. Further studies are needed to further examine rSO2 in preterm infants.

Abstract 14998: Assessment of Microcirculatory Dysfunction by Measuring Subcutaneous Tissue Oxygen Saturation Using Near-Infrared Spectroscopy in Patients With Circulatory Failure

Background: Patients with circulatory failure have been treated with the goal of normalizing systemic hemodynamic parameters such as blood pressure, central venous pressure, urine output, and central venous oxygen saturation. However, microcirculatory dysfunction remains even after improvement of these indices, suggesting a loss of hemodynamic coherence between the macrocirculation and the microcirculation. Recently, the usefulness of near-infrared spectroscopy (NIRS) in assessing the microcirculation has been reported. Aim: We measure regional tissue oxygenation saturation (rSO 2 ) at 3 - 5 mm subcutaneously in patients with circulatory failure using a finger-mounted tissue oximeter with the NIRS technique (Toccare: Astem Co., Ltd., Kawasaki, Japan) to investigate its relationship with microcirculation. Methods: This is a single-center prospective observational cohort study of patients with circulatory failure (systolic blood pressure ≤ 90 mmHg or lactate ≥ 2 mmol/L at presentation) transported to the emergency department of Nihon University Hospital from 15 June 2020 to 31 March 2022. We measured rSO 2 in the forehead, thenar eminence, thumb and knee using Toccare and assessed the relationship between rSO 2 and blood pressure, acute physiology and chronic health evaluation (APACHE) II score, sequential organ failure assessment (SOFA) score and mottling score. Result: In patients with circulatory failure (n = 38), rSO 2 at each site showed no correlation with blood pressure, a negative correlation with SOFA score and APACHE II score and a positive correlation with mottling score. These significant correlations were also best observed in the knee. Conclusion: In patients with circulatory failure, rSO 2 measured with Toccare showed no correlation with blood pressure but a significant negative correlation with the severity of organ damage. The knee is possibly the optimal measurement site for monitoring microcirculatory dysfunction and determining the effectiveness of treatment.

154. EVALUATION OF BLOOD FLOW IN RECONSTRUCTED GASTRIC TUBE AND IDENTIFICATION OF OPTIMAL ANASTOMOSES IN ESOPHAGECTOMY

Abstract Background Anastomotic leakage in esophageal cancer surgery may be reduced by the evaluated blood flow to the reconstructed organ, but it is difficult to evaluate quantitatively arterial and venous blood flow. This study aimed to evaluate quantitatively blood flow that has not been possible before, and to determine the relationship between the blood flow in the gastric tube with anastomosis leakage using near-infrared spectroscopy. Methods This single-center, observational study included 50 patients aged 51 to 82 who underwent radical esophagectomy with gastric tube reconstruction for esophageal cancer from 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, alongside the decreasing rate of oxygen saturation at the three points, were investigated in relation to anastomosis leakage. Results Regional tissue oxygen saturation at points X and Z after gastric tube formation was significantly lower in the presence of leakage than in its absence. The decreasing rate of regional tissue oxygen saturation at point Z was significantly higher in the presence of leakage than in its absence. There was no significant difference in the decreasing rate of regional tissue oxygen saturation at point X and Y between the presence and absence of leakage. The cut-off decreasing rate of the rSO2 was 29.4%. Conclusion Regional tissue oxygen saturation levels may be useful for measuring blood flow and may be a predictor of anastomosis leakage.

Association between regional oxygen saturation and central venous saturation in pediatric patients undergoing cardiac surgery: A prospective observational study.

We evaluated the correlation between regional oxygen saturation (rSO2 ) in the frontal and right renal dorsum (cerebral rSO2 and somatic rSO2 ) measured by near-infrared spectroscopy (INVOS™ 5100C, Medtronic) and central venous oxygen saturation (ScvO2 ) measured with a fiber-optic oximetry catheter (PediaSat™, Edwards Lifesciences) during surgery in order to determine whether noninvasive rSO2 could be used as an alternative to ScvO2 in pediatric cardiac surgery patients. We evaluated the correlation between regional tissue oxygen saturation (cerebral rSO2 and somatic rSO2 ) measured by near-infrared spectroscopy and other patient measures with central venous oxygen saturation (ScvO2 ) measured with a fiber-optic oximetry catheter to track global oxygen supply demand as a potential alternative or supplement to ScvO2 . This single-center prospective observational study enrolled 33 children (weight < 10 kg) who underwent cardiac surgery for congenital heart disease between February 2018 and November 2021. ScvO2 , cerebral rSO2 , and somatic rSO2 were recorded simultaneously after anesthesia induction and central venous catheter placement. Pearson's correlation coefficient and Bland-Altman analysis were used to determine the relationship between ScvO2 and rSO2 . We conducted correlation, Bland Altman, and multiple regression analyses to identify associations between rSO2 , patient measures, and ScvO2 values. The patients' median age was 11.0 (quartile 2.0-16.0) months. Their weight was 7.2 (quartile 4.5-9.2) kg. Cerebral rSO2 was significantly positively correlated with ScvO2 (r2 = 0.29, p = .002 in all patients; r2 = 0.61, p = .013 in the patients without mixing at the atrial level), whereas somatic rSO2 was not. The Bland-Altman analysis demonstrated biases [95% confidence interval; 95% CI] (lower and upper limits of agreement [95% CI]) of 0.27% [-4.26 to 4.80] (-24.79 [-32.61 to -16.96] to 25.33 [17.50 to 33.16]) between cerebral rSO2 and ScvO2 and 0.91% [-5.48 to 7.30] (-34.43 [-45.47 to -23.39] to 36.25 [25.21 to 47.29]) between somatic rSO2 and ScvO2 . Preoperative brain natriuretic peptide (BNP) and SpO2 were independent variables associated with ScvO2 and cerebral and somatic rSO2 . Cerebral rSO2 , SpO2 , and BNP were significantly correlated with ScvO2 , although the cerebral rSO2 correlation was greater for lesions without atrial mixing. rSO2 , BNP, and SpO2 might be used to track changes in ScvO2 but cerebral rSO2 is not sufficiently precise to replace it.

Differences between Hepatic and Cerebral Regional Tissue Oxygen Saturation at the Onset of Intradialytic Hypotension.

Intradialytic hypotension (IDH) is a critical pathological condition associated with all-cause mortality in patients undergoing hemodialysis (HD). However, few studies have investigated IDH-related changes in hepatic and cerebral regional tissue oxygen saturation (rSO2). This study investigated IDH-induced changes in hepatic and cerebral rSO2. Hepatic and cerebral rSO2 during HD were measured using an INVOS 5100C oxygen saturation monitor, and their percentage (%) changes during the development of IDH were analyzed. Ninety-one patients undergoing HD were investigated, including twenty with IDH. In patients with IDH, % changes in hepatic and cerebral rSO2 decreased at the onset of IDH. Additionally, the % change in hepatic rSO2 was significantly larger than that in cerebral rSO2 (p < 0.001). In patients without IDH, no significant differences were found between the % changes in hepatic and cerebral rSO2 at the time of the lowest systolic blood pressure during HD. Multivariable linear regression analysis showed that the difference between the % changes in cerebral and hepatic rSO2 was significantly associated with the development of IDH (p < 0.001) and the ultrafiltration rate (p = 0.010). Hepatic and cerebral rSO2 significantly decreased during the development of IDH, and hepatic rSO2 was more significantly decreased than cerebral rSO2 at the onset of IDH.

0901 An odd presentation of a hidden curse

Abstract Introduction Congenital central hypoventilation syndrome (CCHS) is a rare disorder of respiratory deficiency due to a mutation in the PHOX2B gene. Clinical presentation may be mild in certain individuals due to different levels of ventilatory dysregulation. Methods We present the findings of exogenous ventilatory challenge testing and polysomnography (PSG) performed on a normocapnic adult female with late-onset (LO) CCHS patient. Results The patient was exposed to four separate ventilatory challenges. During exposure to hyperoxia using 100% oxygen (O2) administration, patient showed an inconsistent ventilatory response with a blunted and delayed increase in regional tissue oxygen saturation (rSO2). During hyperoxic hypercapnia with 5% carbon dioxide (CO2) and 95% O2, she demonstrated a reduced ventilatory response based on respiratory rate and tidal volume. During hypoxic hypercapnia, 7% CO2 and 14% O2, patient demonstrated a delayed and markedly attenuated ventilatory response. Hypoxia; 100% nitrogen inhalation did not result in increased ventilation. Ve slope, change in minute ventilation/change in end-tidal CO2 (EtCO2), with hypercapnia challenges was 4.88, which is lower than normal. Ventilatory EtCO2 threshold was 36 mmHg. PSG showed apnea-hypopnea index 3.3 with hypoxemia during rapid eye movement (REM), with an oxygen saturation nadir of 84%. EtCO2 baseline was around 36, peak was 50 and was associated with REM-related apnea events. Arterial blood gas was unremarkable. Conclusion CCHS is characterized by abnormal respiratory response to exogenous ventilatory challenge testing. Hyperoxia silences peripheral chemoreceptors (PC) responsible for stimulating ventilation in normal individuals. Hyperoxic hypercapnia silences PC but stimulates central chemoreceptors (CC). Hypoxic hypercapnia stimulates hyperventilation via both PC and CC. Our patient demonstrated inconsistent and reduced ventilatory responses to all four challenges. As expected, the classic chemosensory parameter, Ve slope, for hypercarbia challenge was markedly reduced. However, the ventilatory EtCO2 threshold fell well below threshold typically observed in CCHS. PSG noted greater alveolar hypoventilation during REM compared to non-REM, which is also atypical for CCHS. In conclusion, exogenous ventilatory challenge testing demonstrated derangements in ventilatory control typical in CCHS. Despite this, our patient had no evidence of daytime hypoventilation with normal CO2 threshold. This case illustrates the phenotypic variability present in LO-CCHS. Support (if any)

The Influence of Extracerebral Tissue on Continuous Wave Near-Infrared Spectroscopy in Adults: A Systematic Review of In Vivo Studies.

Near-infrared spectroscopy (NIRS) is a non-invasive technique for measuring regional tissue haemoglobin (Hb) concentrations and oxygen saturation (rSO2). It may be used to monitor cerebral perfusion and oxygenation in patients at risk of cerebral ischemia or hypoxia, for example, during cardiothoracic or carotid surgery. However, extracerebral tissue (mainly scalp and skull tissue) influences NIRS measurements, and the extent of this influence is not clear. Thus, before more widespread use of NIRS as an intraoperative monitoring modality is warranted, this issue needs to be better understood. We therefore conducted a systematic review of published in vivo studies of the influence of extracerebral tissue on NIRS measurements in the adult population. Studies that used reference techniques for the perfusion of the intra- and extracerebral tissues or that selectively altered the intra- or extracerebral perfusion were included. Thirty-four articles met the inclusion criteria and were of sufficient quality. In 14 articles, Hb concentrations were compared directly with measurements from reference techniques, using correlation coefficients. When the intracerebral perfusion was altered, the correlations between Hb concentrations and intracerebral reference technique measurements ranged between |r| = 0.45-0.88. When the extracerebral perfusion was altered, correlations between Hb concentrations and extracerebral reference technique measurements ranged between |r| = 0.22-0.93. In studies without selective perfusion modification, correlations of Hb with intra- and extracerebral reference technique measurements were generally lower (|r| < 0.52). Five articles studied rSO2. There were varying correlations of rSO2 with both intra- and extracerebral reference technique measurements (intracerebral: |r| = 0.18-0.77, extracerebral: |r| = 0.13-0.81). Regarding study quality, details on the domains, participant selection and flow and timing were often unclear. We conclude that extracerebral tissue indeed influences NIRS measurements, although the evidence (i.e., correlation) for this influence varies considerably across the assessed studies. These results are strongly affected by the study protocols and analysis techniques used. Studies employing multiple protocols and reference techniques for both intra- and extracerebral tissues are therefore needed. To quantitatively compare NIRS with intra- and extracerebral reference techniques, we recommend applying a complete regression analysis. The current uncertainty regarding the influence of extracerebral tissue remains a hurdle in the clinical implementation of NIRS for intraoperative monitoring. The protocol was pre-registered in PROSPERO (CRD42020199053).

Real-Time Assessment of Tissue Oxygen Saturation Using a Novel Oximeter During Revascularization for Acute Limb Ischemia: A Case Report

Emergency surgery was performed to treat acute lower limb ischemia caused by heart thromboembolism and concomitant popliteal artery aneurysm. Using a near-infrared spectroscopy oximeter, regional tissue oxygen saturation (rSO2) was monitored to assess the tissue perfusion pre-, intra-, and postoperatively. rSO2 values did not increase sufficiently following thromboembolectomy of the superficial femoral artery, but they dramatically recovered after additional popliteal-anterior tibial bypass surgery. The affected limb was successfully salvaged. rSO2 monitoring was easily measured intraoperatively, which might be beneficial in evaluating tissue perfusion in patients with acute limb ischemia.

Cognitive Function Deterioration After Cardiopulmonary Bypass: Can Intraoperative Optimal Cerebral Regional Tissue Oxygen Saturation Predict Postoperative Cognitive Function?

Cognitive impairment is a common neurologic complication after cardiac surgery with cardiopulmonary bypass (CPB). This study evaluated postoperative cognitive function to determine predictors of cognitive dysfunction, including intraoperative cerebral regional tissue oxygen saturation (rSO2). A prospective observational cohort study. At a single academic tertiary-care center. A total of 60 adults undergoing cardiac surgery with CPB from January to August 2021. None. All patients underwent Mini-Mental State Examination (MMSE) and quantified electroencephalography (qEEG) 1 day before cardiac surgery, 7 days postoperatively (POD7), and POD60. Intraoperative cerebral rSO2 was monitored continuously. For MMSE, no significant decrease in MMSE score was found on POD7 versus preoperatively (p=0.09), but POD60 scores showed significant improvement compared with both preoperative (p=0.02) and POD7 scores (p < 0.001). On qEEG, relative theta power on POD7 was increased versus preoperatively (p < 0.001), but it was decreased on POD60 (POD7 versus POD60, p < 0.001), and was close to preoperative data (p > 0.99). Baseline rSO2 was an independent factor for postoperative MMSE. Both baseline and mean rSO2 showed a significant influence in postoperative relative theta activity, whereas mean rSO2 was the only predictor for the theta-gamma ratio (p=0.04). The MMSE in patients undergoing CPB declined at POD7 and recovered by POD60. Lower baseline rSO2 indicated a higher potential for MMSE decline at POD60. Inferior intraoperative mean rSO2 was related to higher postoperative relative theta activity and theta-gamma ratio, implying subclinical or further cognitive impairment.

Cerebral regional tissue Oxygen Saturation to Guide Oxygen Delivery in preterm neonates during immediate transition after birth (COSGOD III): multicentre randomised phase 3 clinical trial

ObjectiveTo investigate whether monitoring of cerebral tissue oxygen saturation using near infrared spectroscopy in addition to routine monitoring combined with defined treatment guidelines during immediate transition and resuscitation increases survival...

Microvascular effects of oxygen and carbon dioxide measured by vascular occlusion test in healthy volunteers.

Changes in near-infrared spectroscopy-derived regional tissue oxygen saturation (StO2) during a vascular occlusion test (VOT; ischemic provocation of microcirculation by rapid inflation and deflation of a tourniquet) allow estimating peripheral tissue O2 consumption (desaturation slope; DS), vascular reactivity (recovery slope; RS) and post-ischemic hyperperfusion (AUC-H). The effects of isolated alterations in the inspiratory fraction of O2 (FiO2) and changes in expiratory CO2 remain to be elucidated. Therefore, in this secondary analysis we determined the effects of standardized isolated instances of hypoxia, hyperoxia, hypocapnia and hypercapnia on the VOT-induced StO2 changes in healthy volunteers (n=20) to establish reference values for future physiological studies. StO2 was measured on the thenar muscle. Multiple VOTs were performed in a standardized manner: i.e. at room air (baseline), during hyperoxia (FiO2 1.0), mild hypoxia (FiO2≈0.11), and after a second baseline, during hypocapnia (end-tidal CO2 (etCO2) 2.5-3.0vol%) and hypercapnia (etCO2 7.0-7.5vol%) at room air. Differences in DS, RS, and AUC-H were tested using repeated-measures ANOVA. DS and RS remained constant during all applied conditions. AUC-H after hypoxia was smaller compared to hyperoxia (963%*sec vs hyperoxia 1702%*sec, P=0.005), while there was no difference in AUC-H duration between hypoxia and baseline. The StO2 peak (after tourniquet deflation) during hypoxia was lower compared to baseline and hyperoxia (92% vs 94% and 98%, P<0.001). We conclude that in healthy volunteers at rest, common situations observed during anesthesia and intensive care such as exposure to hypoxia, hyperoxia, hypocapnia, or hypercapnia, did not affect peripheral tissue O2 consumption and vascular reactivity as assessed by VOT-induced changes in StO2. These observations may serve as reference values for future physiological studies. This study represents a secondary analysis of an original study which has been registered at ClinicalTrials.gov nr: NCT02561052.

Laryngoscopy mediated stress response induces opposite effects on cerebral and paraspinal oxygen saturation

Background: Intraoperative sympathetic stimulation induces a cascade of metabolic and hormonal changes. It increases perfusion of vital organs, but also causes vasoconstriction of blood vessels supplying less vital organs, potentially leading to organ injury. To date, it is unknown how an endogenous stress reaction affects the spinal cord blood supply. Near-infrared spectroscopy (NIRS) can be applied paravertebrally to monitor the oxygenation of the collateral network, which contributes to the spinal cord blood supply. It has already been demonstrated that regional cerebral oxygen saturation (rScO2) increases following sympathetic stimulation. Objectives: We hypothesized that laryngoscopy would cause an increase in cerebral and paraspinal regional tissue saturations (rScO2 and rSpsO2, respectively). Design: Retrospective analysis of a previous conducted randomized trial. Setting: Laryngoscopy in the operating room. Methods: Data of 28 patients, scheduled for arterial dilation of the lower limb, were retrospectively analyzed. Before induction of anesthesia, standard monitoring, BIS and 8 NIRS sensors were applied (two on the forehead, six bilaterally on the back at T3-T4, T9-T10 and L1-L2). Sympathetic stimulation was induced by laryngoscopy. Main outcome measures: Changes in rStO2 following sympathetic stimulation induced by laryngoscopy. Results: Following laryngoscopy, rScO2 significantly increased and rSpsO2 significantly decreased at T9-T10 and L1-L2. The relative changes (regional tissue oxygen saturation (rStO2) after intubation-rStO2 before intubation)/ rStO2 before intubation), at cerebral level, T9-T10 and L1-L2 were 9%, -5% and -3%, respectively (p &lt; 0.01). rSpsO2 at T3-T4 did not change significantly. Changes (Δ) in mean arterial pressure following laryngoscopy were weakly correlated with ΔrScO2 and moderately correlated with ΔrSpsO2 at T9-T10 and L1-L2. Conclusions: Intraoperative sympathetic stimulation may decrease the oxygen supply to the spinal cord. Trial registration: The trial was registered at ClinicalTrials.gov (NCT 03767296).

Near-infrared spectroscopy in the medical management of infants

Near-infrared spectroscopy (NIRS) is a technology that is easy to use and can provide helpful information about organ oxygenation and perfusion by measuring regional tissue oxygen saturation (rSO2) with near-infrared light. The sensors can be placed in different anatomical locations to monitor rSO2 levels in several organs. While NIRS is not without limitations, this equipment is now becoming increasingly integrated into modern healthcare practice with the goal of achieving better outcomes for patients. It can be particularly applicable in the monitoring of pediatric patients because of their size, and especially so in infant patients. Infants are ideal for NIRS monitoring as nearly all of their vital organs lie near the skin surface which near-infrared light penetrates through. In addition, infants are a difficult population to evaluate with traditional invasive monitoring techniques that normally rely on the use of larger catheters and maintaining vascular access. Pediatric clinicians can observe rSO2 values in order to gain insight about tissue perfusion, oxygenation, and the metabolic status of their patients. In this way, NIRS can be used in a non-invasive manner to either continuously or periodically check rSO2. Because of these attributes and capabilities, NIRS can be used in various pediatric inpatient settings and on a variety of patients who require monitoring. The primary objective of this review is to provide pediatric clinicians with a general understanding of how NIRS works, to discuss how it currently is being studied and employed, and how NIRS could be increasingly used in the near future, all with a focus on infant management.

Monitoring of intraoperative femoral oxygenation predicts acute kidney injury after pediatric cardiac surgery.

Cardiopulmonary bypass-associated acute kidney injury (CPB-AKI) is a pediatric cardiac surgery postoperative complication that is associated with a longer duration of mechanical ventilation and length of hospital stay. Identifying an early predictor of CPB-AKI is critical. Near infrared spectroscopy (NIRS), which can provide real-time monitoring of regional tissue oxygen saturation (rSO2) during CPB, may predict CPB-AKI in an early phase of surgical treatment. This study analyzed clinical data from 87 children who underwent an elective surgical repair of ventricular septal defect (VSD) from January 2013 to March 2019. NIRS sensors were placed on the patients' forehead, abdomen, and thighs. The pediatric modified risk, injury, failure, loss, and end-stage (p-RIFLE) score was determined for each patient postoperatively. The incidence of AKI based on the p-RIFLE classification was 11.5% at the end of surgery, 23.0% at 24 h after surgery, and 5.7% at 48 h after surgery. The AKI incidence rate was highest at 24 h after surgery. Multiple regression analysis revealed that femoral oxygenation (rSO2) during CPB, CPB time, oxygen delivery index (DO2i), and lactate at the end of CPB were independent risk factors for AKI. Receiver-operating characteristic curve analysis indicated that femoral oxygenation of 74% or less predicted AKI development within 24 h after surgery. In conclusion, rSO2 measured at the thigh during CPB is highly predictive of CPB-AKI.

Optimal bispectral index level of sedation and cerebral oximetry in traumatic brain injury: a non-invasive individualized approach in critical care?

BackgroundImpaired cerebral autoregulation has been linked with worse outcomes, with literature suggesting that current therapy guidelines fail to significantly impact cerebrovascular reactivity. The cerebral oximetry index (COx_a) is a surrogate measure of cerebrovascular reactivity which can in theory be obtained non-invasively using regional brain tissue oxygen saturation and arterial blood pressure. The goal of this study was to assess the relationship between objectively measured depth of sedation through BIS and autoregulatory capacity measured through COx_a.MethodsIn a prospectively maintained observational study, we collected continuous regional brain tissue oxygen saturation, intracranial pressure, arterial blood pressure and BIS in traumatic brain injury patients. COx_a was obtained using the Pearson’s correlation between regional brain tissue oxygen saturation and arterial blood pressure and ranges from − 1 to 1 with higher values indicating impairment of cerebrovascular reactivity. Using BIS values and COx_a, a curve-fitting method was applied to determine the minimum value for the COx_a. The associated BIS value with the minimum COx_a is called BISopt. This BISopt was both visually and algorithmically determined, which were compared and assessed over the whole dataset.ResultsOf the 42 patients, we observed that most had a parabolic relationship between BIS and COx_a. This suggests a potential “optimal” depth of sedation where COx_a is the most intact. Furthermore, when comparing the BISopt algorithm with visual inspection of BISopt, we obtained similar results. Finally, BISopt % yield (determined algorithmically) appeared to be independent from any individual sedative or vasopressor agent, and there was agreement between BISopt found with COx_a and the pressure reactivity index (another surrogate for cerebrovascular reactivity).ConclusionsThis study suggests that COx_a is capable of detecting disruption in cerebrovascular reactivity which occurs with over-/under-sedation, utilizing a non-invasive measure of determination and assessment. This technique may carry implications for tailoring sedation in patients, focusing on individualized neuroprotection.

Monitoring of gastrointestinal dysfunction by near-infrared spectroscopy in children with sepsis: a prospective study

To investigate the incidence and mortality of gastrointestinal dysfunction in children with sepsis, the application of near-infrared spectroscopy (NIRS) in monitoring mesenteric regional tissue oxygen saturation (rSO2), and the association between rSO2 and gastrointestinal dysfunction. In this prospective study, 79 children with sepsis in the pediatric intensive care unit (sepsis group) and 40 children who underwent physical examination in the Department of Child Healthcare (healthy control group) from January to December, 2021 were enrolled as subjects. The related medical data were collected, including general information on admission and at discharge, treatment during hospitalization, and laboratory examination results. NIRS was used to measure mesenteric rSO2. Clinical characteristics were compared between the patients with and without gastrointestinal dysfunction. For the 79 children with sepsis, the incidence rate of gastrointestinal dysfunction was 49% (39/79), and the mortality rate of the children with gastrointestinal dysfunction was 26% (10/39). The children with gastrointestinal dysfunction had a longer duration of mechanical ventilation and a higher 28-day mortality rate (P<0.05). The children with gastrointestinal dysfunction had a significantly lower median rSO2 (64%) than the children without gastrointestinal dysfunction (72%) and the healthy control group (78%) (P<0.05). There are high incidence and mortality rates of gastrointestinal dysfunction in children with sepsis, and the reduction in rSO2 may be associated with the development of gastrointestinal dysfunction.

Ultrasound-guided erector spinae plane block in patients undergoing pediatric abdominal surgery: a randomized study

BackgroundErector spinae plane block (ESPB) can provide effective analgesia in pediatric abdominal surgery. Additionally, when used as an analgesic method in abdominal surgery, ESPB may increase regional intra-abdominal tissue oxygen saturation (rSO2) throughout the operation. However, the number of related studies conducted on pediatric patients is insufficient.ResultsFifty-two patients undergoing lower abdominal surgery were allocated into two groups, the ESPB (E) and the control (C). Group E received general anesthesia plus unilateral ultrasound-guided ESPB, and group C received general anesthesia alone. Intraoperative fentanyl consumption, Face, Legs, Activity, Cry, Consolability (FLACC) score, time to first rescue analgesia and adverse events were recorded over the first 24 h postoperatively. The rSO2 level was evaluated in both groups throughout the operation. The FLACC score was significantly lower in group E than in group C (p<0.05). Four patients in group E required intraoperative fentanyl compared to 12 patients in group C (p<0.05). The first rescue analgesic administration time was significantly longer in group E than in group C (p<0.05). No significant difference in rSO2 values was detected between the groups (p>0.05). However, in group E, rSO2 values were significantly increased after the block compared to the postinduction values.ConclusionsESPB provides effective perioperative analgesia in children undergoing low abdominal surgery. Although there was no significant difference in rSO2 values between the groups, ESPB administration consistently increases rSO2 over time.Trial registrationThe trial was registered at ClinicalTrials.gov before patient enrolment (NCT03808129-13.12.2018).