Changes In Near-infrared Spectroscopy Research Articles

Revisiting the Role of Balloon Atrial Septostomy Prior to the Arterial Switch Operation.

Patients with dextro-transposition of the great arteries (d-TGA) frequently undergo balloon atrial septostomy (BAS) prior to the arterial switch operation (ASO) to promote atrial-level mixing. Balloon atrial septostomy has inherent risks as an invasive procedure and may not always be necessary. This study revisits the routine utilization of BAS prior to ASO. Single-center, retrospective review of d-TGA patients undergoing the ASO from July 2018 to March 2023. Preoperative patient characteristics, pulse oximetry oxygen saturations (SpO2), cerebral/renal near-infrared spectroscopy (NIRS) readings along with prostaglandin status at the time of the ASO were analyzed with descriptive and univariate statistics. Thirty patients underwent the ASO. Of these, 7 (23%) were female, 25 (83%) were white, and median weight at ASO was 3.2 kg (range 0.8-4.2). Twenty-two (73%) patients underwent BAS. There were no demographic differences between BAS and no-BAS patients. Of those who underwent BAS, there was a significant increase in SpO2 (median 83% [range 54-92] to median 87% [range 72-95], P = .007); however, there was no change in NIRS from pre-to-post BAS. Six (27%) patients in the BAS group were prostaglandin-free at ASO. Balloon atrial septostomy patients underwent the ASO later compared with no-BAS patients (median 8 [range 3-32] vs 4 [range 2-10] days old, P = .016) and had a longer hospital length of stay (median 13 [range 7-43] vs 10 [range 8-131] days, P = .108). While BAS is an accepted preoperative procedure in d-TGA patients to improve oxygen saturations, it is also an additional invasive procedure, does not guarantee prostaglandin-free status at the time of ASO, and may increase the interval to ASO. Birth to direct early ASO, with prostaglandin support, should be revisited as an alternative, potentially more expeditious strategy.

Changes in transcranial near-infrared spectroscopy values reflect changes in cardiac index during cardiac surgery.

To determine whether changes in transcranial near-infrared spectroscopy (NIRS) values reflect changes in cardiac index (CI) in adult cardiac surgical patients. Single-center prospective post hoc analysis. University hospital. One hundred and twenty-four adult patients undergoing cardiac surgery. In each patient, several CI measurements were taken, and NIRS values were collected simultaneously. We used a hierarchical linear regression model to assess the association between NIRS values and CI. We calculated a crude model with NIRS as the only factor included, and an adjusted model, where mean arterial pressure, end-tidal CO2 , and oxygen saturation were used as confounding factors. A total of 1301 pairs of NIRS and CI values were collected. The analysis of separate NIRS and CI pairs revealed a poor association, which was not statistically significant when adjusted with the chosen confounders. However, when the changes in NIRS from baseline or from the previous measurement were compared to those of CI, a clinically and statistically significant association between NIRS and CI was observed also in the adjusted model. Compared to the baseline and to the previous measurement, respectively, the regression coefficients with 95% confidence intervals were 0.048 (0.041-0.056) and 0.064 (0.055-0.073) in off-pump coronary artery bypass patients and 0.022 (0.016-0.029) and 0.026 (0.020-0.033) in patients who underwent cardiopulmonary bypass. In an unselected cardiac surgical population, the changes in NIRS values reflect those in CI, especially in off-pump coronary artery bypass patients. In this single-center post hoc analysis of data from a prospectively collected database of cardiac surgery patients, paired measurements of cardiac output and NIRS revealed that while there was a no correlation between individual paired measurements, a small correlation was found in changes in the two measurements from baseline values. This highlights a potential to utilize changes in NIRS from baseline to suggest changes in cardiac output in cardiac surgical populations.

Factors Predicting Early Major Adverse Events in the Intensive Care Unit After Successful Cardiac Surgery for Congenital Heart Disease in Full-Term Neonates.

In this study, we aimed to evaluate the factors affecting major adverse event (MAE) development after full-term neonatal cardiac surgery. This study was conducted retrospectively on newborns who underwent congenital heart surgery between June 1, 2020, and June 1, 2022. MAE was defined as the presence of at least one of the following: cardiac arrest, unplanned reoperation, emergency chest opening, admission to the advanced life support system, and death. The role of blood lactate level, vasoactive inotropic score (VIS), and cerebral near-infrared spectroscopy (NIRS) changes in predicting MAE was investigated. A total of 240 patients (50% male) were operated during the study period. The median age of patients was seven days (interquartile range 3-10 days). MAE was detected in 19.5% of the cases. Peak blood lactate levels >7 mmol/liter (area under the curve [AUC] 0.72, 95% confidence interval [CI] [0.62-0.82], P<0.001, sensitivity 76%, specificity 82%, positive predictive value [PPV] 88%) was an independent risk factor for MAE (odds ratio [OR] 2.7 [95% CI 1.3-6]). More than 30% change in NIRS value during the operative period (AUC 0.84, 95% CI [0.80-0.88], P<0.001, sensitivity 65%, specificity 85%, PPV 90%) was a strong predictor of MAE. VIS > 10 was an independent risk factor (AUC 0.75, 95% CI [0.70-0.84], P<0.001, sensitivity 86%, specificity 80%, PPV 84%) and strongly predicted MAE (OR 1.4 [95% CI 0.9-5]). Cerebral NIRS changes > 30%, high blood lactate levels, and VIS score within the 48 hours may help to predict the development of MAE in the postoperative period.

Relationship Between Brain Tissue Oxygen and Near-Infrared Spectroscopy in Patients with Nontraumatic Subarachnoid Hemorrhage.

Continuous monitoring of cerebral oxygenation is one of the diagnostic tools used in patients with brain injury. Direct and invasive measurement of cerebral oxygenation with a partial brain oxygen pressure (PbtO2) probe is promising but invasive. Noninvasive assessment of regional transcranial oxygen saturation using near-infrared spectroscopy (NIRS) may be feasible. The aim of this study was to evaluate the interchangeability between PbtO2 and NIRS over time in patients with nontraumatic subarachnoid hemorrhage. This retrospective study was performed in a neurocritical care unit. Study participants underwent hourly PbtO2 and NIRS measurements over 72h. Temporal agreement between markers was described by their pointwise correlation. A secondary analysis assessed the structure of covariation between marker trajectories using a bivariate linear mixed model. Fifty-one patients with subarachnoid hemorrhage were included. A total of 3362 simultaneous NIRS and PbtO2 measurements were obtained. The correlation at each measurement time ranged from - 0.25 to 0.25. The global correlation over time was - 0.026 (p = 0.130). The bivariate linear mixed model confirmed the lack of significant correlation between the PbtO2 and NIRS measurements at follow-up. NIRS was unable to detect PbtO2 values below 20mm Hg (area under the receiver operating characteristic curve 0.539 [95% confidence interval 0.536-0.542]; p = 0.928), and percentage changes in NIRS were unable to detect a decrease in PbtO2 ≥ 10% (area under the receiver operating characteristic curve 0.615 [95% confidence interval 0.614-0.616]; p < 0.001). PbtO2 and NIRS measurements were not correlated. There is no evidence that NIRS could be a substitute for PbtO2 monitoring in patients with nontraumatic subarachnoid hemorrhage.

Early Changes in Near-Infrared Spectroscopy Are Associated With Cardiac Arrest in Children With Congenital Heart Disease.

BackgroundThe association of near-infrared spectroscopy (NIRS) with various outcomes after pediatric cardiac surgery has been studied extensively. However, the role of NIRS in the prediction of cardiac arrest (CA) in children with heart disease has yet to be evaluated. We sought to determine if a model utilizing regional cerebral oximetry (rSO2c) and somatic oximetry (rSO2s) could predict CA in children admitted to a single-center pediatric cardiac intensive care unit (CICU).MethodsWe retrospectively reviewed 160 index CA events for patients admitted to our pediatric CICU between November 2010 and January 2019. We selected 711 control patients who did not have a cardiac arrest. Hourly data was collected from the electronic health record (EHR). We previously created a machine-learning algorithm to predict the risk of CA using EHR data. Univariable analysis was done on these variables, which we then used to create a multivariable logistic regression model. The outputs from the model were presented by odds ratio (OR) and 95% confidence interval (CI).ResultsWe created a multivariable model to evaluate the association of CA using five variables: arterial saturation (SpO2)- rSO2c difference, SpO2-rSO2s difference, heart rate, diastolic blood pressure, and vasoactive inotrope score. While the SpO2-rSO2c difference was not a significant contributor to the multivariable model, the SpO2-rSO2s difference was. The average SpO2-rSO2s difference cutoff with the best prognostic accuracy for CA was 29% [CI 26–31%]. In the multivariable model, a 10% increase in the SpO2-rSO2s difference was independently associated with increased odds of CA [OR 1.40 (1.18, 1.67), P < 0.001] at 1 h before CA. Our model predicted CA with an AUROC of 0.83 at 1 h before CA.ConclusionIn this single-center case-control study of children admitted to a pediatric CICU, we created a multivariable model utilizing hourly data from the EHR to predict CA. At 1 h before the event, for every 10% increase in the SpO2-rSO2s difference, the odds of cardiac arrest increased by 40%. These findings are important as the field explores ways to capitalize on the wealth of data at our disposal to improve patient care.

Percutaneous Common Carotid Artery Access for Cardiac Interventions in Infants Does Not Acutely Change Cerebral Perfusion.

Pediatric cardiac interventions via percutaneous common carotid artery (CCA) access have been shown to be safe and effective. However, the impact of placement of a sheath in the carotid artery for interventions on cerebral perfusion is unknown. In this study we used cerebral near-infrared spectroscopy (NIRS) to analyze the effects of percutaneous CCA access for cardiac interventions on cerebral perfusion. This study is a retrospective chart review carried out at a tertiary care center on all pediatric patients who underwent percutaneous cardiac catheterization via carotid artery access from January 2010 to January 2020. All patients who had ipsilateral NIRS recorded on the side of carotid artery access were included. Patients with only partial or no ipsilateral NIRS data were excluded. The primary outcome measure was the change in NIRS upon CCA access; the mean NIRS for 15min before obtaining access was compared to the mean NIRS during the procedure and to the mean NIRS 15min after removal of the CCA sheath. We hypothesized that there would be a significant drop in NIRS values on the side of CCA access. There were 48 catheterizations in the study period where percutaneous CCA was accessed. Of those, 21 catheterizations had complete data and were included in the study. 13 (62%) were of males. The median age was 23days (IQR 7-79). The indications for CCA access were patent ductus arteriosus stent implantation (n = 13; 62%), aortic valvuloplasty (n = 5; 24%), balloon angioplasty of coarctation of aorta (n = 2; 10%), and renal artery angioplasty (n = 1; 4%). In 16 patients (72%), the left common carotid artery was accessed. The median weight of the patients was 3.3kg (IQR 2.8-2.9). The most common sheath size used was 4F, in 16 patients (72%). The mean NIRS prior to the procedure was 67 ± 15%, during the procedure was 68 ± 20%, and after removal of sheath was 68 ± 21%. Paired t test of cerebral NIRS before, during, and after the procedure showed no significant change with CCA access (P = 0.08). No patient in the series had a documented neurologic deficit following the procedure. Percutaneous CCA access was not associated with a decrease in NIRS on the side of the access during the procedure, suggesting there was no significant acute change in cerebral perfusion with CCA access.

Comparison of bilateral cerebral and somatic tissue oxygenation with near-infrared spectroscopy in cyanotic and acyanotic pediatric patients receiving cardiac surgery.

IntroductionCompromise of tissue oxygenation during surgery is associated with increased mortality and morbidity in the postoperative period in patients with congenital cardiac disorders. It may be monitored with near-infrared spectroscopy (NIRS). We aimed to evaluate the tissue oxygenation and factors which may affect it by bilateral cerebral and somatic NIRS levels during cardiopulmonary bypass and to compare the NIRS values of cyanotic and acyanotic patient groups.Material and methodsTwo groups of patients with cyanotic and acyanotic congenital heart diseases were included in the study. Each group consisted of 15 patients between 0 and 5 years of age. All data were collected following anesthesia induction (T1), the 10th (T2) and 30th min (T3) of cardiopulmonary bypass (CPB), every 30 min during CPB (T4, T5, T6) and 1 h after (TS). Bilateral and somatic NIRS, blood gases, mean arterial pressure, and temperatures were recorded.ResultsLeft and right somatic NIRS values in groups at all measurements did not differ significantly. Left and right cerebral NIRS values at T2 and T3 in cyanotic patients were significantly higher than in acyanotic patients. Mean arterial pressure and lactate levels at T1 and T3 measurements were responsible for left cerebral NIRS changes and mean arterial pressure on right cerebral NIRS values.ConclusionsMonitorization of tissue perfusion has critical importance during CPB of patients with congenital heart defects. Oxygenation may easily and reliably be measured with NIRS. Cerebral and somatic NIRS are more pronounced in cyanotic patients and cerebral NIRS is strongly associated with mean arterial pressure and circulating lactate levels.

Monitoring of Delayed Cerebral Ischemia in Patients with Subarachnoid Hemorrhage via Near-Infrared Spectroscopy.

We investigated the role of near infrared spectroscopy (NIRS) in identifying delayed cerebral ischemia (DCI) in patients with subarachnoid hemorrhage (SAH). We measured the cerebral regional oxygen saturation (rSO2) continuously for 14 days. The differences in rSO2 according to DCI were analyzed. We also compared the diagnostic accuracy of NIRS and transcranial Doppler ultrasonography (TCD) for DCI detection using the area under receiver operator characteristic (ROC) curve. Fifty-two patients treated with coil embolization were enrolled, including 18 with DCI (34.6%) and 34 without DCI (65.4%). Significant differences in rSO2 levels were observed from days 7 to 9. The rSO2 level was 60.95 (58.10–62.30) at day 7 in the DCI vs. 63.90 (62.50–67.10) in the non-DCI patients. By day 8, it was 59.50 (56.90–64.50) in the DCI vs. 63.30 (59.70–68.70) in the non-DCI cases. By day 9, it was 61.85 (59.40–65.20) in the DCI vs. 66.00 (62.70–68.30) in the non-DCI. A decline of >12.7% in SO2 rate yielded a sensitivity of 94.44% (95% CI: 72.7–99.9%) and a specificity of 70.59% (95% CI: 52.5–84.9%) for identifying DCI. Changes in NIRS tended to yield better diagnostic accuracy than TCD, but were not statistically significant. NIRS is a feasible method for real-time detection of DCI.

Near-infrared spectroscopy-derived total haemoglobin as an indicator of changes in muscle blood flow during exercise-induced hyperaemia

ABSTRACTBlood flow changes in response to exercise have been attributed, among other factors, to the effect of vasodilators factors on the microvasculature, suggesting a close relationship between small blood vessels and conducting arteries. The main purpose of this study was to determine the relationship between the changes in near infrared spectroscopy (NIRS)-derived total haemoglobin ([tHb]) and muscle oxygen saturation (SmO2) signals and femoral artery blood flow in response to resistance exercise at fast- and slow-velocity muscle contraction. The study randomised crossover design included twelve participants. NIRS and blood flow measurements were continuously monitored before, during, and 5 min after the exercise protocol. There was a significant correlation between [tHb] reperfusion slope ([tHb]slope) and peak blood flow (BFpeak) after slow- and fast-velocity muscle contraction (r = 0.83, p = 0.0008 and r = 0.72, p = 0.0080, respectively). No significant correlation existed between the SmO2 reperfusion slope (SmO2_slope) and BFpeak after both slow- and fast-velocity muscle contraction exercise (r = −0.46, p = 0.1253 and r = 0.33, p = 0.2841, respectively). This study demonstrated a strong relationship between the NIRS-derived [tHb] and Doppler ultrasound BF during the recovery period of dynamic resistance exercise at both slow- and fast-velocity contraction.

Investigation of the Relationship between Cerebral Near-Infrared Spectroscopy Measurements and Cerebrovascular Event in Coronary Artery Bypass Grafting Operation in Patients without Carotid Stenosis and Patients with Carotid Stenosis below Surgical Margins.

ObjectivesStroke is an important cause of mortality and morbidity in surgery. In the present study, we examined the cerebral oximetry values of patients with carotid artery stenosis who did not present surgical indications and those who did not present carotid artery stenosis in coronary artery bypass grafting (CABG) surgery by comparing their cerebral oximetry values with cerebrovascular disease (CVD).MethodsBetween January and May 2014, 40 patients who underwent isolated CABG were included in the study. Cerebral oximetry probes were placed prior to induction of anesthesia. Cerebral oximetry values were recorded before induction, in the pump (cardiopulmonary bypass) inlet period, in the post-clamp period, in the pump outlet period, and in the intensive care unit and neurological complications.ResultsThere was no difference between the groups in terms of demographic data and routine follow-up parameters. Intraoperative surgical data and early postoperative results were similar in both groups. When comparing the groups, there were no statistically significant results in cerebral oximetry values and CVD development. Only one patient in group 2 had postoperative CVD and this patient was discharged from the hospital with right hemiplegia. Mean arterial pressure (MAP)levels were significantly higher in Group 2 (P<0.05).ConclusionThe follow-up of cerebral perfusion with a method like near-infrared spectroscopy (NIRS) will ensure that MAP is adjusted with interventions that will be made according to changes in NIRS. Thus, it will be possible to avoid unnecessary medication and flow-rate increase with cerebral oxygen saturation (rSO2) follow-up.

Deviation From Personalized Blood Pressure Targets Is Associated With Worse Outcome After Subarachnoid Hemorrhage.

Background and Purpose- Optimal blood pressure (BP) management during the early stages of aneurysmal subarachnoid hemorrhage remains uncertain. Observational studies have found worse outcomes in patients with increased hemodynamic variability, suggesting BP optimization as a potential neuroprotective strategy. In this study, we calculated personalized BP targets at which cerebral autoregulation was best preserved. We analyzed how deviation from these limits correlates with functional outcome. Methods- We prospectively enrolled 31 patients with aneurysmal subarachnoid hemorrhage. Autoregulatory function was continuously measured by interrogating changes in near-infrared spectroscopy (NIRS)-derived tissue oxygenation-a surrogate for cerebral blood flow-as well as intracranial pressure (ICP) in response to changes in mean arterial pressure using time-correlation analysis. The resulting autoregulatory indices were used to identify the upper and lower limit of autoregulation. Percent time that mean arterial pressure exceeded limits of autoregulation was calculated for each patient. Functional outcome was assessed using the modified Rankin Scale at discharge and 90 days. Associations with outcome were analyzed using ordinal multivariate logistic regression. Results- Personalized limits of autoregulation were computed in all patients (age 57.5±13.4, 23F, mean World Federation of Neurological Surgeons 2±1, monitoring time 67.8±50.8 hours). Optimal BP and limits of autoregulation were calculated on average for 89.5±6.7% of the total monitoring period. ICP- and NIRS-derived optimal pressures strongly correlated with one another (P<0.0001). Percent time that mean arterial pressure deviated from limits of autoregulation significantly associated with worse functional outcome at discharge (NIRS, P=0.001; ICP, P=0.004) and 90 days (NIRS, P=0.002; ICP, P=0.003), adjusting separately for age, World Federation of Neurological Surgeons, vasospasm, and delayed cerebral ischemia. Conclusions- Both invasive (ICP) and noninvasive (NIRS) determination of personalized BP targets after aneurysmal subarachnoid hemorrhage is feasible, and these 2 approaches revealed significant collinearity. Furthermore, exceeding individualized limits of autoregulation was associated with poor functional outcomes.

Deviation from Dynamic and Personalized Optimal Blood Pressure Targets is Associated With Worse Functional Outcomes After Aneurysmal Subarachnoid Hemorrhage

Abstract INTRODUCTION Effective blood pressure (BP) management after aneurysmal subarachnoid hemorrhage (aSAH) is critical for maintaining optimal cerebral perfusion and protecting the brain from further injury. How to best manage BP during the early stages of aSAH remains uncertain. In this study, we calculated individualized BP thresholds at which cerebral autoregulation was best preserved. We analyzed how deviating from these limits correlates with functional outcome. METHODS We prospectively enrolled 31 patients with aSAH. Autoregulatory function was continuously measured by interrogating changes in near-infrared spectroscopy (NIRS)-derived tissue oxygenation – a surrogate for cerebral blood flow – as well as intracranial pressure (ICP) in response to changes in mean arterial pressure (MAP) using time-correlation analysis. The resulting autoregulatory indices were used to trend BP ranges at which autoregulation was most preserved. The percent time that MAP exceeded limits of autoregulation (LA) was calculated for each patient. Functional outcome was assessed using the modified Rankin Scale (mRS) at discharge and 90 d. Associations with outcome were analyzed using ordinal multivariate logistic regression. RESULTS Personalized LA were computed in all patients (age 57.5, 23F, mean WFNS 2, monitoring time 67.8 h). Optimal BP and LA were calculated on average for 89.5% of the total monitoring period. ICP- and NIRS-derived optimal pressures and LA strongly correlated with one another (P &lt; .0001). Percent time that MAP deviated from LA significantly associated with worse functional outcome at discharge (NIRS P = .001, ICP P = .004) and 90 d (NIRS P = .002, ICP P = .003), adjusting separately for age, WFNS, vasospasm, or delayed cerebral ischemia. CONCLUSION Both invasive (ICP) and non-invasive (NIRS) determination of personalized BP thresholds for aSAH patients is feasible, and these 2 approaches revealed significant collinearity. Exceeding individualized autoregulatory thresholds may increase the risk of poor functional outcomes.

Cerebral NIRS—How low is low?

Cerebral near-infrared spectroscopy (NIRS), a noninvasive means of monitoring cerebral oxygenation, is inferred to reflect the balance between tissue oxygen delivery and consumption. Although some studies have demonstrated an association between cerebral NIRS and intellectual outcome in special populations, such as those with hypoplastic left heart syndrome (J Thorac Cardiovasc Surg 2016;151:1358-66), questions remain regarding broader applicability. Although frequently used during anesthesia for congenital heart surgery, use in a broader surgical population is not established, including in adult patients (Anesth Analg 2012;115:1373-83). With this in mind, the report by Gómez-Pesquera et al in this volume of The Journal is intriguing, but raises as many questions as it answers. This was an observational study of 198 children undergoing non-cardiac surgery. A validated questionnaire was administered on post-operative day 7, and an association was found with negative behaviors (including anxiety, eating disturbances, and apathy/withdrawal) for every 1% decrease from baseline in cerebral oxygenation by NIRS. A similar association was found when comparing the degree of preoperative anxiety as measured by the modified Yale Preoperative Anxiety Scale with post-operative behaviors. General anesthesia is, of course, unavoidable at times, but these findings should prompt further inquiry into the consequences of anesthetic exposure to the developing brain. This study does not address the severity of behavioral changes nor whether there are any long-term consequences, because the only reported outcome is a survey at 7 days. And although it challenges the notion of extrapolating adult thresholds to children, it remains difficult to assess to what degree of decrement is worrisome, since, unlike systemic oxygen saturation, there are no hard and fast cutoffs for cerebral NIRS. All reports are expressed as change from baseline, with a wide biologic variability in that baseline. An additional concern is whether changing management in response to cerebral NIRS changes outcomes, as evidenced by a growing body of literature in neonates (Curr Opin Pediatr 2018;30:209-15) (Acta Paediatr 2019;108:275-81). So, although premature to advocate for specific indications or thresholds for use of cerebral NIRS during pediatric surgery, this report should encourage further investigations into the nature and consequences of anesthesia and the most effective monitoring of the developing brain. Article page 207▶ Cerebral Oxygen Saturation and Negative Postoperative Behavioral Changes in Pediatric Surgery: A Prospective Observational StudyThe Journal of PediatricsVol. 208PreviewTo evaluate if an intraoperative cerebral regional oxygen saturation (crSO2) decrease, less pronounced than 20% below baseline (the current threshold believed to be associated with cognitive dysfunction in adults), is associated with negative postoperative behavioral changes (NPOBC) in the pediatric population after noncardiac surgeries. Full-Text PDF

Abstract 95: Exceeding Personalized Blood Pressure Targets After Endovascular Stroke Therapy is Associated With Hemorrhagic Transformation and Worse Functional Outcome

Background: Effective blood pressure (BP) management after endovascular stroke therapy (EVT) is critical for maintaining optimal cerebral perfusion and to protect the brain from hyperperfusion. A single, universal BP target below 180/105 mmHg is likely inadequate in this highly heterogeneous patient population. We calculated individualized BP thresholds at which cerebral autoregulation was best preserved and analyzed how exceeding these limits correlates with hemorrhagic transformation (HT) and functional outcome. Methods: 51 patients with large-vessel occlusion (LVO) stroke who underwent EVT were prospectively enrolled. Autoregulatory function was continuously measured by interrogating changes in near-infrared spectroscopy and mean arterial pressure (MAP). The resulting autoregulatory index was used to identify and trend the BP range at which autoregulation was most preserved (Figure 1A). The percent time that MAP exceeded the upper limit of autoregulation (ULA) was calculated for each patient. HT was identified on CT imaging at 24 hours. Functional outcome was assessed using the modified Rankin Scale (mRS). Associations among percent time above ULA, HT and mRS were analyzed using ordinal or logistic regression, adjusting for age, TICI score and baseline NIHSS. Results: Personalized limits of autoregulation could be computed in 36 patients (mean age 71±15, 12 F, mean admission NIHSS 15±6, average monitoring time 26±19 hours, HT=17). Optimal BP and limits of autoregulation were calculated for 83±11% of the total monitoring period. Percentage of time with MAP above ULA was associated with HT (p=0.016, OR 1.15, 95% CI 1.02-1.29) and worse functional outcome at discharge (p&lt;0.004, OR 1.13, 95% CI 1.04-1.22) and 90 days (p=0.003, OR 1.22, 95% CI 1.06-1.38) (Figure 1B - D). Conclusions: Non-invasive determination of personalized BP thresholds for LVO stroke patients is feasible; exceeding these limits may increase the risk of HT and worse clinical outcomes.

Effects of hypnotics on prefrontal cortex activity during a verbal fluency task in healthy male subjects: A near-infrared spectroscopy study.

To assess the effects of hypnotics on prefrontal cortex activity in healthy subjects using near-infrared spectroscopy (NIRS) in a double-blind, placebo-controlled crossover trial. Eighteen healthy males received acute doses of ramelteon (8mg), triazolam (0.125mg), or placebo in a predetermined randomization schedule, with a washout period of more than 1week. All subjects performed a verbal fluency task during NIRS assessments at baseline and at 1 and 4hr post-dose. The number of words correctly generated during the task (behavioral performance) and scores on the Stanford Sleepiness Scale (SSS) were also recorded at each test time. Compared with the placebo, triazolam (0.125mg) significantly decreased oxyhemoglobin (oxy-Hb) concentration change in NIRS during the posttask period and significantly increased behavioral performance, whereas triazolam (0.125mg) and ramelteon (8mg) significantly increased SSS scores. The differential effects of two types of hypnotics on oxy-Hb change measured by NIRS were observed in acute dosing, suggesting that when assessing brain activity of patients with psychiatric disorders, researchers should consider how certain types of hypnotics can influence brain function. This would also provide useful information to clinicians when prescribing hypnotics suitable for their patients' conditions.

Multi-modal pain assessment: are near-infrared spectroscopy, skin conductance, salivary cortisol, physiologic parameters, and Neonatal Facial Coding System interrelated during venepuncture in healthy, term neonates?

BackgroundImproving pain and stress assessments in neonates remains important in preventing the short- and long-term consequences. We aimed to identify the relationships between different pain assessment parameters by simultaneously measuring changes in cortical, autonomic, hormonal, physiological, and behavioral evoked responses to venepuncture in healthy, full-term neonates.MethodsThis observational, prospective study (ancillary to the ACTISUCROSE trial) included 113 healthy, 3-day old, full-term neonates who underwent venepuncture for systematic neonatal screening, from July to October 2013, in a tertiary-level maternity ward of a university hospital. During venepuncture, we simultaneously measured the cortical single-channel near-infrared spectroscopy (NIRS) signals, foot skin conductance, salivary cortisol, physiological responses, and behavioral (Neonatal Facial Coding System [NFCS]) evoked responses.ResultsRegarding the NIRS analysis, the highest correlation was between the NFCS at venepuncture and the change in NIRS integrated values of total hemoglobin (r=0.41, P<0.001) or oxygenated hemoglobin (r=0.27, P<0.001). The NFCS at venepuncture was moderately positively correlated with changes in salivary cortisol (r=0.42, P<0.001) and skin conductance (r=0.29, P<0.001). Salivary cortisol and skin conductance changes were not correlated; the latter parameters were not correlated with heart rate, respiratory rate, or SpO2.ConclusionDuring venepuncture, NFCS was mildly or moderately correlated with salivary cortisol, skin conductance, and cortical NIRS changes.

Changes in Near-Infrared Spectroscopy After Congenital Cyanotic Heart Surgery.

Since oxygen saturation from pulse oximetry (SpO2) and partial pressure of arterial oxygen (PaO2) are observed to improve immediately after surgical correction of cyanotic congenital heart disease (CHD), we postulate that cerebral (CrO2) and somatic (SrO2) oximetry also improves immediately post-correction. We aim to prospectively examine CrO2 and SrO2, before, during, and after surgical correction as well as on hospital discharge in children with cyanotic CHD to determine if and when these variables increase. This is a prospective observational trial. Eligibility criteria included children below 18 years of age with cyanotic CHD who required any cardiac surgical procedure. CrO2 and SrO2 measurements were summarized at six time-points for comparison: (1) pre-cardiopulmonary bypass (CPB); (2) during CPB; (3) post-CPB; (4) Day 1 in the pediatric intensive care unit (PICU); (5) Day 2 PICU; and (6) discharge. Categorical and continuous variables are presented as counts (percentages) and median (interquartile range), respectively. Twenty-one patients were analyzed. 15 (71.4%) and 6 (28.6%) patients underwent corrective and palliative surgeries, respectively. In the corrective surgery group, SpO2 increased immediately post-CPB compared to pre-CPB [99 (98, 100) vs. 86% (79, 90); p < 0.001] and remained in the normal range through to hospital discharge. Post-CPB CrO2 did not change from pre-CPB [72.8 (58.8, 79.0) vs. 72.1% (63.0, 78.3); p = 0.761] and even decreased on hospital discharge [60.5 (53.6, 62.9) vs. 72.1% (63.0, 78.3); p = 0.005]. Post-CPB SrO2 increased compared to pre-CPB [87.3 (77.2, 89.5) vs. 72.7% (65.6, 77.3); p = 0.001] but progressively decreased during PICU stay to a value lower than baseline at hospital discharge [66.9 (57.3, 76.9) vs. 72.7% (65.6, 77.3); p = 0.048]. CrO2 and SrO2 did not increase after corrective surgery of cyanotic CHD even up to hospital discharge. Future larger studies are required to validate these findings. (This study is registered with ClinicalTrials.gov ID: NCT02417259.).

Pulse Pressure Analysis to Guide Intraoperative Phlebotomy Prior to Cardiac Surgery.

BackgroundThe aim of this study was to evaluate the response of the LiDCO-rapid™ during intraoperative phlebotomy in anesthetized children prior to surgery for congenital heart disease.MethodsAfter the induction of general anesthesia and endotracheal intubation, baseline vital signs were recorded, along with pulse pressure variability (PPV) and stroke volume variability (SVV) from the LiDCO-rapid™ and cerebral oxygenation (rSO2) using near-infrared spectroscopy (NIRS). Phlebotomy was performed over 5 - 10 min with the volume of blood removed calculated to achieve a hematocrit of 24-28% on cardiopulmonary bypass. The primary outcome was a decline in rSO2 ≥ 5 between the baseline value and the end of phlebotomy. At that time, the correlation of the starting and ending values of SVV and PPV with the NIRS was determined.ResultsThe study cohort included 30 patients (mean age of 21 ± 11 years). Statistically significant changes during the study period were observed in rSO2, but not in the LiDCO-rapid™ parameters. In analysis of continuous NIRS data, the change in NIRS did not correlate with either baseline (r = 0.10, P = 0.644) or final (r = 0.02, P = 0.914) SVV. Likewise, the change in NIRS did not correlate with baseline (r = 0.01, P = 0.953) or final (r = 0.00, P = 0.982) PPV.ConclusionBaseline values as well as changes in the PVV and SVV from the LiDCO-rapid™ did not predict or correlate with changes in cerebral oxygenation measured by NIRS during intraoperative phlebotomy. Our preliminary data suggest that these parameters (PVV and SVV) are not useful in monitoring patient stability or the need for volume replacement during intraoperative phlebotomy prior to cardiac surgery.

Changes in Brain Oxygenation in Response to Inhaled 100% Oxygen Are Different in Sickle Cell Disease Patients

Introduction: The prevalence of silent stroke increases monotonically with age in SCD patients, with more than 50% developing detectable white matter hyperintensities on MRI by adulthood. We are exploring the use of inhaled oxygen as a contrast agent to try to identify individuals at risk for silent stroke and to better understand how the brain regulates its own oxygen delivery. In this study, we report changes of brain Blood Oxygen Level Dependent (BOLD) signal and frontal Near Infrared Spectroscopy (NIRs) to 5 minutes of inhaled 100% oxygen in patients with sickle cell disease (SCD), non sickle anemia (ACTL), and control subjects.Method: The study was approved by the institutional review board and performed at Children’s Hospital Los Angeles (CHLA); all patients provided informed consent. Patients with previous stroke, pregnancy, and acute chest pain and crisis hospitalization within one month were excluded. 19 SCD patients (age = 20.7 ± 8.8), 12 patients with non sickle anemia syndromes (age = 25.1 ± 6.9) and 20 ethnicity matched control (CTL) subjects (age = 30.5 ± 12.7) were studied. Peripheral oxygen saturation (SpO2%) was measured by MRI compatible pulse oximeter. A five minute BOLD sequence was acquired with the patient breathing room air for 50 seconds, followed by 100% oxygen for 250 seconds. NIRS recordings of oxygenated hemoglobin change (DOHB), deoxygenated hemoglobin change (DDHB) and tissue oxygenation index (TOI) were recorded from the patient’s forehead. Average BOLD signal was from a 6 cm slab in the middle of the brain. CBC, hemoglobin electrophoresis, and markers of hemolysis were also measured.Results: A representative frontal DOHB signal, and the parameters used to characterize its time-course, are shown in Figure 1. DOHB remained stable until oxygen was administered and then increased over several minutes to a maximum. In many patients, the DOHB signal subsequently declined back toward baseline, representing the effects of compensatory cerebral vasoconstriction. The delay time was shorter in anemic subjects because of increased cerebral blood flow, but the rise times were not different. Peak DOHB increase was greater in SCD patients than in ACTL or non anemic control subjects (1.4 mM ± 0.2mM, 0.8 mM ± 0.2 mM and 0.6 mM ± 0.4 mM, respectively, p <0.0001 by ANOVA). There was no difference in the DOHB vasoconstriction response among the three patient groups.DOHB was highly correlated with DDHB and DTOI in all three patient groups. Consequently, both DDHB and DTOI changes were also larger in SCD patients. All three NIRs signal changes were larger in non-transfused SCD patients than in patients on chronic transfusions. Non-transfused SCD patients had more significant increases in SpO2% than chronically transfused subjects and the effect was proportional to hemoglobin F%, suggesting a p50 effect. After controlling for SpO2%, SCD patients still exhibited larger NIRs changes than ACTL or CTL patients, but the differences between transfused and non transfused SCD patients disappeared.Whole brain %BOLD was also correlated with changes in DOHB, DDHB, TOI, and SpO2%. The relationship between DOHB versus %BOLD is illustrated in Figure 2. %BOLD changes were also significantly higher in SCD patients. However, unlike the NIRS changes, whole brain %BOLD differences could entirely be explained by differences in SpO2% with hyperoxia.Conclusion:100% oxygen administration increases brain oxygenation in SCD patients to a greater degree than in control subjects or patients with anemia of other etiologies. Some of the differences can be explained by differences in resting oxygen saturations but disparities between BOLD and NIRs response suggest regional variation of brain oxygenation in response to this challenge. [Display omitted] [Display omitted] DisclosuresWood:Apopharma: Consultancy; AMAG: Consultancy; World Care Clinical: Consultancy; AMAG: Consultancy; Celgene: Consultancy; Apopharma: Consultancy; Biomed Informatics: Consultancy; Celgene: Consultancy; Ionis Pharmaceuticals: Consultancy; Vifor: Consultancy; Vifor: Consultancy; Ionis Pharmaceuticals: Consultancy; Biomed Informatics: Consultancy; World Care Clinical: Consultancy.

Influence of Adjuvant Therapy in Cancer Survivors on Endothelial Function and Skeletal Muscle Deoxygenation.

The cardiotoxic effects of adjuvant cancer treatments (i.e., chemotherapy and radiation treatment) have been well documented, but the effects on peripheral cardiovascular function are still unclear. We hypothesized that cancer survivors i) would have decreased resting endothelial function; and ii) altered muscle deoxygenation response during moderate intensity cycling exercise compared to cancer-free controls. A total of 8 cancer survivors (~70 months post-treatment) and 9 healthy controls completed a brachial artery FMD test, an index of endothelial-dependent dilation, followed by an incremental exercise test up to the ventilatory threshold (VT) on a cycle ergometer during which pulmonary and changes in near-infrared spectroscopy (NIRS)-derived microvascular tissue oxygenation (TOI), total hemoglobin concentration ([Hb]total), and muscle deoxygenation ([HHb] ≈ fractional O2 extraction) were measured. There were no significant differences in age, height, weight, and resting blood pressure between cancer survivors and control participants. Brachial artery FMD was similar between groups (P = 0.98). During exercise at the VT, TOI was similar between groups, but [Hb]total and [HHb] were significantly decreased in cancer survivors compared to controls (P < 0.01) The rate of change for TOI and [HHb] relative to were decreased in cancer survivors compared to controls (P = 0.02 and P = 0.03 respectively). In cancer survivors, a decreased skeletal muscle microvascular function was observed during moderate intensity cycling exercise. These data suggest that adjuvant cancer therapies have an effect on the integrated relationship between O2 extraction, and O2 delivery during exercise.