Cerebral Tissue Oxygen Saturation Research Articles

Effects of Synchronization during Noninvasive Intermittent Mandatory Ventilation in Preterm Infants with Respiratory Distress Syndrome Immediately after Extubation

Background: Noninvasive ventilation is increasingly used in very-low-birth-weight infants (VLBWI) to reduce complications that occur with invasive ventilation. However, the physiological effects of synchronization during noninvasive nasal intermittent mandatory ventilation (IMV) have not been tested in VLBWI immediately after extubation. Objective: We aimed to study the short-term effects of synchronized nasal IMV (S-NIMV) compared to nonsynchronized nasal IMV (NIMV) on breathing effort as measured by phasic esophageal pressure (Pe) deflection, spontaneous respiratory rate (RR), gas exchange, cerebral tissue oxygen saturation (StO₂) and intermittent episodes of bradycardia or hypoxemia in VLBWI recovering from respiratory distress syndrome (RDS). Methods: Fourteen VLBWI recovering from RDS were studied using a randomized cross-over design during both S-NIMV and NIMV (of 2 h each) immediately after extubation. Results: Phasic Pe deflection, spontaneous RR and transcutaneous PCO₂ decreased significantly while transcutaneous PO₂ and synchrony rate (defined as peak ventilator pressure delivered within the first half of spontaneous inspiration) increased significantly during S-NIMV compared to during NIMV. There was no difference in blood pressure, average arterial oxygen saturation (SpO₂), cerebral StO₂, fractional tissue oxygen extraction of the brain and severe bradycardia (defined as time with a heart rate <100 beats/min lasting ≥10 s) and in hypoxemic episodes (SpO₂ <80%) between the two modes. Conclusion: Synchronization during nasal ventilation immediately after extubation in VLBWI recovering from RDS improved gas exchange and decreased the respiratory effort, and it could therefore be considered to provide a more efficient respiratory support and synchrony.

0353 : Cerebral tissue oxygen saturation monitoring during balloon atrial septostomy in neonates with transposition of the great arteries. Preliminary data

Balloon atrial septostomy (BAS) increases peripheral oxygen saturation in neonates with transposition of the great vessels (TGV). Effect of BAS on cerebral oxygenation remains little known. We aimed to describe the modification of regional cerebral tissue oxygen saturation (rcSaO 2 ) during the catheterization. we prospectively included 6 neonates with TGV and restrictive inter-atrial shunt who required BAS. BAS was performed in catheterization laboratory by an interventional pediatric cardiologist. rcSaO 2 was measured using near-infrared spectroscopy (NIRS) during the whole procedure. Median rcSa0 2 at the beginning of the procedure was 52.5% ranging from 21% to 78%. Median rcSaSaO 2 after the BAS was 69.5% ranging from 64% to 94%. The rcSa0 2 increased significantly immediately after the BAS (p=0.0273 by Wilcoxon signed rank test). Median rcSa0 2 delta between before and after BAS was 19% ranging from 11 to 43%. The rcSaO 2 delta was higher although not significantly when rcSa02 before the BAS was less than 50% (31% vs 16%, p=0.14). Linear regression analysis revealed that the delta of rcSaO 2 was significantly inversely related to the rcSa0 2 at the beginning of the procedure (Delta= –0.45 x rcSaO 2 av + 45.8, p=0.37, R 2 =0.70). BAS improves cerebral oxygen saturation during the catheterization in neonates with TGV and restrictive inter-atrial shunt. The increase is proportional to the degree of alteration before the procedure.

Coupling between arterial pressure, cerebral blood velocity, and cerebral tissue oxygenation with spontaneous and forced oscillations

We tested the hypothesis that transmission of arterial pressure to brain tissue oxygenation is low under conditions of arterial pressure instability. Two experimental models of hemodynamic instability were used in healthy human volunteers; (1) oscillatory lower body negative pressure (OLBNP) (N = 8; 5 male, 3 female), and; (2) maximal LBNP to presyncope (N = 21; 13 male, 8 female). Mean arterial pressure (MAP), middle cerebral artery velocity (MCAv), and cerebral tissue oxygen saturation (ScO2) were measured non-invasively. For the OLBNP protocol, between 0 and −60 mmHg negative pressure was applied for 20 cycles at 0.05 Hz, then 20 cycles at 0.1 Hz. For the maximal LBNP protocol, progressive 5 min stages of chamber decompression were applied until the onset of presyncope. Spectral power of MAP, mean MCAv, and ScO2 were calculated within the VLF (0.04–0.07 Hz), and LF (0.07–0.2 Hz) ranges, and cross-spectral coherence was calculated for MAP-mean MCAv, MAP-ScO2, and mean MCAv-ScO2 at baseline, during each OLBNP protocol, and at the level prior to pre-syncope during maximal LBNP (sub-max). The key findings are (1) both 0.1 Hz OLBNP and sub-max LBNP elicited increases in LF power for MAP, mean MCAv, and ScO2 (p ≤ 0.08); (2) 0.05 Hz OLBNP increased VLF power in MAP and ScO2 only (p ≤ 0.06); (3) coherence between MAP-mean MCAv was consistently higher (≥0.71) compared with MAP-ScO2, and mean MCAv-ScO2 (≤0.43) during both OLBNP protocols, and sub-max LBNP (p ≤ 0.04). These data indicate high linearity between pressure and cerebral blood flow variations, but reduced linearity between cerebral tissue oxygenation and both arterial pressure and cerebral blood flow. Measuring arterial pressure variability may not always provide adequate information about the downstream effects on cerebral tissue oxygenation, the key end-point of interest for neuronal viability.

Impact of Intraoperative Events on Cerebral Tissue Oximetry in Patients Undergoing Cardiopulmonary Bypass

Previous studies showed that decreased cerebral saturation during cardiac surgery is related to adverse postoperative outcome. Therefore, we investigated the influence of intraoperative events on cerebral tissue saturation in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). A total of 52 adult patients who underwent cardiac surgery using pulsatile CPB were included in this prospective explorative study. Cerebral tissue oxygen saturation (SctO2) was measured in both the left and right cerebral hemisphere. Intraoperative events, involving interventions performed by anesthesiologist, surgeon, and clinical perfusionist, were documented. Simultaneously, in-line hemodynamic parameters (partial oxygen pressure, partial carbon dioxide pressure, hematocrit, arterial blood pressure, and CPB flow rates) were recorded. Cerebral tissue saturation was affected by anesthetic induction (p &lt; .001), placement of the sternal retractor (p &lt; .001), and initiation (p &lt; .001) as well as termination of CPB (p &lt; .001). Placement (p &lt; .001) and removal of the aortic cross-clamp (p = .026 for left hemisphere, p = .048 for right hemisphere) led to changes in cerebral tissue saturation. In addition, when placing the aortic cross-clamp, hematocrit (p &lt; .001) as well as arterial (p = .007) and venous (p &lt; .001) partial oxygen pressures changed. Cerebral tissue oximetry effectively identifies changes related to surgical events or vulnerable periods during cardiac surgery. Future studies are needed to identify methods of mitigating periods of reduced cerebral saturation.

In preterm infants, ascending intrauterine infection is associated with lower cerebral tissue oxygen saturation and higher oxygen extraction.

Placental lesions are associated with neurological morbidity but the mechanism leading to morbidity is unclear. To provide insight into such a possible mechanism, we determined whether placental lesions were associated with regional cerebral tissue oxygen saturation (rcSO2) and fractional tissue oxygen extraction (FTOE) in preterm infants during their first 5 d after birth. We hypothesized that as a result of cerebral hypoperfusion, rcSO2 would be lower and FTOE would be higher. In a prospective, observational study of 42 preterm infants (gestational age <32 wk), the infants' placentas were examined for histopathology. We measured rcSO2 and transcutaneous arterial oxygen saturation (SpO2) on days 1-5. FTOE was calculated as FTOE = (transcutaneous SpO2 - rcSO2)/transcutaneous SpO2. Only three placentas showed no pathology. Ascending intrauterine infection (AIUI) (n = 16) was associated with lower rcSO2 and higher FTOE values on days 2, 3, and 4 (P ≤ 0.05). Other placental lesions were not associated with rcSO2 and FTOE. AIUI is associated with lower rcSO2, and higher FTOE shortly after birth. The effect it has on cerebral oxygenation might be the mechanism leading to neurodevelopmental problems.

The values shown on optical technology-based patient monitors must be cautiously interpreted: intravenous dye-induced errors.

Intravenous dyes such as indocyanine green (ICG), indigo carmine, and methylene blue are commonly used during various surgical procedures. The intraoperative administration of intravenous dyes can result in misreadings of the actual values measured by optical technology-based patient monitors (i.e., cerebral oximeters and pulse oximeters) because they interfere with the amount of the specific infrared or red wavelength detected by each device. Therefore, clinicians would benefit from a narrow review of the effects of intravenously administered dyes on regional cerebral tissue oxygen saturation and percutaneous oxygen saturation readings. The pulse oximeter was developed based on the fact that oxygenated and reduced hemoglobin have different rates of absorption of red and infrared light (Lambert-Beer law). Oxyhemoglobin absorbs more infrared light (990 nm), whereas deoxyhemoglobin absorbs more red light (660 nm). The device detects the difference in the extent of absorption of two wavelengths of light (660 and 925 nm) in arterial blood. The value is automatically calculated as an absorption ratio (extent of light detected at 660 nm/extent of light detected at 925 nm) and is represented as the arterial oxygen saturation (SaO2). Similar to pulse oximetry, cerebral near-infrared spectrometry measures the absorption ratio of two different wavelengths of near-infrared light (730 and 805 nm) in venous, capillary, and arterial blood and represents the value as the regional cerebral tissue oxygen saturation (SctO2). In clinical practice, intraoperative ICG is commonly used during neurosurgery to confirm the patency of the anastomosed vessels after middle cerebral artery-superficial temporal artery bypass surgery or carotid endarterectomy and the completeness of the secured aneurysm after cerebral aneurysmal clipping. The peak absorption wavelength of ICG is 805 nm [1]. A clinical study published in this issue of the Korean Journal of Anesthesiology demonstrates that the intravenous injection of ICG can produce false increases in SctO2 readings in a dosedependent fashion [2]. This finding can be partly explained by an increase in the absorption ratio of two different wavelengths of light: 730 and 805 nm. In other words, ICG absorbs light with a wavelength of 805 nm, falsely decreasing the amount of 805 nm light detected by the cerebral oximeter; this light is displaced as an increased SctO2 reading. Another recent study showed that intravenous ICG administration caused a false decrease in SaO2 readings [2,3]. ICG acts similarly to deoxyhemoglobin in arterial blood; this falsely decreases the absorption ratio of red and infrared wavelengths detected by the pulse oximeter, resulting in a decreased SaO2 reading. Indigo carmine is commonly used during urologic surgical procedures to identify the ureteral orifices in the bladder. Indigo carmine is a blue dye with peak absorption at around 620 nm [1]. Therefore, intravenous indigo carmine administration, like ICG injection, causes a false decrease in SaO2 readings by decreasing the amount of red light (660 nm) detected by the pulse oximeter. In contrast to ICG, however, indigo carmine administration results in a false reduction in SctO2 readings by decreasing the amount of light with a wavelength of 730 nm detected by the cerebral oximeter [4]. Methylene blue, which is used to treat vasoplegic syndrome in clinical practice [5,6], has an absorption peak at 668 nm and shows a dose-dependent effect on plasma light absorbance, resulting in falsely low values on pulse oximeters and cerebral oximeters [7,8]. In conclusion, clinicians should be aware that the intraoperative administration of various dyes can cause misreadings of the actual values measured by optical technology-based patient monitors, including cerebral oximeters and pulse oximeters, by interfering with the amount of the specific infrared or red wavelength detected by each device.

Effects of intravenously administered indocyanine green on near-infrared cerebral oximetry and pulse oximetry readings.

Background Intravenously administered indocyanine green (ICG) may cause misreadings of cerebral oximetry and pulse oximetry in patients undergoing carotid endarterectomy under general anesthesia. The present study determined the effects of two different doses (12.5 mg vs. 25 mg) of ICG on regional cerebral tissue oxygen saturation (SctO2) and percutaneous peripheral oxygen saturation (SpO2).MethodsTwenty-six patients receiving ICG for videoangiography were divided into two groups according to the dosage (12.5 mg and 25 mg, n = 13 in each group). Heart rate, arterial blood pressure, SctO2, and SpO2 were measured before and after an intravenous bolus administration of ICG.ResultsFollowing the dye administration, no changes in heart rate or arterial blood pressure were noted in either group. SctO2 was increased in both groups; however, the magnitude of the increase was greater (21.6 ± 5.8% vs. 12.6 ± 4.1%, P < 0.0001) and more prolonged (28.4 ± 9.6 min vs. 13.8 ± 5.2 min, P < 0.0001) in the 25 mg group than in the 12.5 mg group. In contrast, SpO2 was decreased in both groups; the magnitude of the decrease was greater in the 25 mg group than in the 12.5 mg group (4.0 ± 0.8% vs. 1.6 ± 1.0%, P < 0.0001). There were no differences in the time to reach the peak SctO2 or to reach the nadir SpO2 between the two groups.ConclusionsIn patients given ICG for videoangiography, a 25 mg bolus results in a greater and more prolonged increase in SctO2 and a greater reduction in SpO2 than a 12.5 mg bolus, with no differences in the time to reach the peak SctO2 or to reach the nadir SpO2.

Cerebral oxygen saturation monitoring during hypotensive anesthesia in shoulder arthroscopy: A comparative study between dexmedetomidine and esmolol

BackgroundBeach chair position (BCP) is used in arthroscopic shoulder operations for its advantages. The BCP together with deliberate hypotension used to decrease intraoperative blood loss during arthroscopic shoulder procedures, this may have risk to cause postoperative neurological insults. Dexmedetomidine and esmolol are used to induce deliberate hypotension. Near-infrared spectroscopy (NIRS) provides a non-invasive technique of continuous monitoring of regional cerebral tissue oxygen saturation (rScO2). In this study we evaluate the prevalence of rScO2 during hypotensive anesthesia induced by intra-operative infusion of either dexmedetomidine or esmolol in patients undergoing elective arthroscopic shoulder surgery in the BCP.Patients and methodsFifty patients scheduled for elective arthroscopic shoulder surgery under general anesthesia with hypotensive technique in BCP, randomly assigned into two equal groups, dexmedetomidine group (D Group) and esmolol group (E Group) according to the drug used for deliberate hypotension. MAP, HR, BIS and rScO2 were recorded before induction of anesthesia T0, post-induction of anesthesia T1 as baseline, 5 min after BCP T2, 5 min after starting the studied drug T3, 30 min T4, 60 min T5, 90 min T6, 5 min after stopping the studied drug T7, 5 min after return to supine T8 and after extubation T9.ResultsIn D group there was significant decrease in Lt.rsco2 and Rt.rsco2, at T2 to T7 compared to T1. In E group there was significant decrease in Lt.rsco2 and Rt.rsco2 at T2, to T7 compared to T1. In D group two patients had CDEs compared to five patients in E group.ConclusionIn patients undergoing shoulder arthroscopic surgery under general anesthesia, the BCP significantly decreases rScO2, with further slight decrease of rScO2 with dexmedetomidine and esmolol induced hypotension with no affection of postoperative cognitive function with both drugs. Dexmedetomidine and esmolol are safe drugs with better safety of dexmedetomidine over esmolol.

Intravenously Administered Indocyanine Green May Cause Falsely High Near-Infrared Cerebral Oximetry Readings

Near-infrared spectroscopy assesses cerebral tissue oxygen saturation (Scto2) based on the absorption spectra of oxygenated and deoxygenated hemoglobin. It has been reported that IV-administered dyes including methylene blue, indigo carmine, and indocyanine green (ICG) may cause falsely low-pulse oximetry readings (Spo2). Although methylene blue and indigo carmine may also decrease Scto2, the effect of ICG has not been documented. Simultaneous changes in the heart rate, arterial blood pressure, Scto2, and Spo2 were measured after IV administration of ICG (12.5 mg diluted in 5.0 mL 0.9% NaCl) in 15 patients undergoing carotid endarterectomy under sevoflurane-remifentanil anesthesia. After the dye administration, no change in heart rate or arterial blood pressure was observed in any patient. Scto2 increased by 13.3±4.0 percentage points, reaching the peak at 42.0±28.4 seconds after the administration, whereas Spo2 decreased by 1.9±1.2 percentage points, reaching the peak at 64.0±42.5 seconds (P<0.0001 both). ICG falsely increases the spectroscopy-determined cerebral oxygen saturation for up to 12 minutes but dampens pulse oximetry readings.

Cerebral Oxygenation during Intermittent Hypoxemia and Bradycardia in Preterm Infants

Background: Episodes of hypoxemia and bradycardia frequently occur with apnea of prematurity in preterm infants. Little is known about the impact of different event types on the brain. Objectives: To describe the influence of hypoxemia and bradycardia, either isolated or in combination, on cerebral oxygenation. Methods: In 16 preterm infants with intermittent hypoxemia and/or bradycardia, cerebral tissue oxygen saturation (StO₂, as measured by near-infrared spectroscopy), heart rate and pulse oximetric saturation (SpO₂) were recorded simultaneously for 16 h. Events were classified as isolated bradycardia (type 1), isolated hypoxemia (type 2) or combined (simultaneous, type 3; bradycardia first, type 4; hypoxemia first, type 5). Primary outcome was a score representing the area below baseline for cerebral StO₂ desaturation during an event. Secondary outcomes were duration and depth of cerebral desaturation. Results: Patients had a median (range) gestational age of 25.9 (22.6-30.4) weeks and a postnatal age of 32.5 (7-58) days. The median (quartiles) number of events was 49 (34-58). Isolated hypoxemias were the most frequent events (24; 9-36) and isolated bradycardias the least common (0; 0-1). Cerebral StO₂ baseline was not different between event types. Cerebral desaturation score, duration of event and depth of cerebral desaturation were smallest for isolated bradycardias and largest for combined events, especially for those starting with hypoxemia followed by bradycardia. Regardless of event type, 12/16 infants maintained cerebral StO₂ >60% despite severe SpO₂ desaturations. Conclusions: Isolated bradycardias had the lowest impact on cerebral desaturation, and combined events had the highest. Most infants preserved cerebral oxygenation >60% during events.

Transient hyperoxia does not affect regional cerebral tissue oxygen saturation in moderately preterm or term newborns.

Even short periods of hyperoxia may induce prolonged cerebral vasoconstriction in newborn infants, and this could theoretically lead to cerebral ischaemia even once normoxia is re-established. This study aimed to investigate the effect of brief hyperoxic exposures on regional cerebral tissue oxygen saturation (rStO2 ) and to evaluate whether any observed prolonged cerebral vasoconstriction was related to maturity. The study included 30 infants with a postmenstrual age of more than 32 weeks, who were treated with nasal continuous positive airway pressure and a fraction of inspired oxygen of ≤0.3. The INVOS 5100C oximeter was used to measure rStO2 before, during and after two hyperoxic exposures. If hyperoxia induced a prolonged cerebral vasoconstriction, posthyperoxic rStO2 would be expected to decrease. rStO2 increased slightly after the first hyperoxic exposure, with a mean difference of 1.37% (95% CI 0.15, 2.6). After the second oxygen exposure, rStO2 remained unchanged with a mean difference of -0.4% (95% CI -1.6, 0.78). Differences in rStO2 were not related to gestational age in either of the two hyperoxic episodes. We found no evidence to support the theory that transient hyperoxia induces prolonged cerebral vasoconstriction in infants with a postmenstrual age above 32 weeks.

Abstract 105: Changes in NIRS-Measured Cerebral Tissue Oxygen Saturation During Hyperventilation: A Comparison Between NIRO™ and INVOS™

Introduction: Cerebral tissue oxygen saturation measured with transcranial near-infrared spectroscopy (NIRS) has been reported to predict neurological outcome of cardiac arrest patients. Because NIRS values are confounded by extracranial tissues, there can be considerable inter-device variation in the measured values. We compared hyperventilation-induced changes in NIRS values measured with 2 commercially available devices in healthy volunteers. Methods: After obtaining an approval from the ethics committee at Iseikai hospital and written informed consents, 29 healthy volunteers joined the study. Probes of NIRO™ 200NX (Hamamatsu Photonics, Japan) and INVOS™ 5100C (Covidien, USA) were applied respectively on the right and left side of the volunteers’ forehead. After obtaining the baseline values, the volunteers were asked to hyperventilate for 40 seconds attempting to reduce the end-tidal CO 2 by ~20 mmHg. Measurements were repeated, after 20 minutes of resting interval, with the probes applied on the contralateral sides. Hyperventilation-induced response of the NIRS value was categorized as “correct” when the average value over the 5 second period toward the end of the hyperventilation decreased by &gt;15% the baseline or “erroneous” otherwise. Results: The mean (± SD) end-tidal CO 2 decreased from the baseline value of 36 ± 5.1 mmHg to 15.2 ± 4.4 mmHg during hyperventilation. Out of 58 measurements with each of the devices, NIRO values were “correct” in 54 (93.1%) measurements, whereas INVOS values were “correct” in 32 (52.2%) measurements. NIRO presented “erroneous” values on both sides of the forehead in no volunteers whereas INVOS presented “erroneous” values in 7 (35%) of 29 volunteers. Discussion: Hyperventilation consistently decreases cerebral blood flow in healthy subjects. Thus, the results of the present study suggest that NIRS devices may fail to reflect correct changes in cerebral tissue oxygen saturation in ~7% of measurements with NIRO and in ~48% with INVOS. The bilateral “erroneous” measurements with INVOS in 7 (35%) volunteers may suggest that INVOS is subject to confounding by extracranial tissues. A potential source of confounding may include the scalp where blood flow increases during hyperventilation.

Effects of Automated Adjustment of the Inspired Oxygen on Fluctuations of Arterial and Regional Cerebral Tissue Oxygenation in Preterm Infants with Frequent Desaturations

To assess the effect of automated adjustment of the inspired oxygen fraction (FiO2) on arterial oxygen saturation (SpO2) and cerebral tissue oxygen saturation (SctO2) in very low birth weight infants with frequent fluctuations in oxygenation. Fifteen infants (median gestational age, 25 weeks [range, 23-28 weeks]; median age, 34 days [range, 19-74 days]) were assigned in random sequence to 24 hours of automated adjustment of FiO2 or manual adjustment of FiO2. Primary outcome measurements were time within the SpO2 target range and the area under the curve above and below a defined SctO2 range. Percentage of time within the SpO2 target range increased during automated FiO2 control (76.3% ± 9.2% vs 69.1% ± 8.2% for manual; P < .01). Prolonged episodes with SpO2 <88% of >60 seconds duration (median, 115 episodes [range, 67-240] vs 54 episodes [range, 7-184]; P < .01) and of >180 seconds duration (median, 13 episodes [range, 6-39] vs 2 episodes [range, 0-5]; P < .01) decreased significantly during the automated period. Percentage of time with SpO2 >96% decreased during automated control (6.6% ± 4.4% vs 10.4% ± 3.3%; P < .02). There was no significant difference in FiO2 exposure. The area (deviation × time) below and above the defined SctO2 threshold did not differ between the 2 periods (median, 59.7%*seconds [range, 17.2%-208.3%] for manual vs 49.0%*seconds [range, 4.3%-193.7%] for automated; P = .36). Automated FiO2 control in preterm infants with frequent SpO2 fluctuations significantly increased the time within the SpO2 target range and reduced the incidence of prolonged hypoxemic events compared with manual FiO2 adjustment, but did not significantly affect cerebral tissue oxygenation.

Cerebral tissue oxygen saturation is associated with N-terminal probrain natriuretic peptide in preterm infants on their first day of life.

This prospective observational study investigated if N-terminal probrain natriuretic peptide (NT-proBNP), a cardiac biomarker, correlated with cerebral tissue oxygen saturation (crSO2) in preterm infants on their first day of life. Using near infrared spectroscopy (NIRS), crSO2 was measured on the right forehead of preterm infants for 24 h. We also recorded arterial oxygen saturation (SpO2 ) and calculated fractional tissue oxygen extraction (cFTOE) values. At the end of the NIRS measurement, blood was taken to analyse NT-proBNP. Mean values for the 24-h period were calculated for crSO2 , cFTOE, SpO2 and these values were correlated to NT-proBNP. An echocardiography was performed in all infants during the measurement period. We analysed 35 preterm neonates (33 ± 2 weeks, 1965 ± 523 g). NIRS measurements started at 3 ± 1 h and blood samples were taken at 24 ± 5 h postnatal. Echocardiography showed an open ductus arteriosus in all infants. Mean NT-proBNP was 4978 ± 3566 pg/mL, crSO2 was 76 ± 8%, and cFTOE was 0.20 ± 0.08. NT-proBNP correlated negatively with crSO2 (r = -0.75; p ≤ 0.001) and positively with cFTOE (r = 0.731; p ≤ 0.001). These results emphasise that crSO2 is influenced by cardiac function, in addition to oxygen consumption, arterial oxygen saturation and vascular resistance, and this can be measured by NT-proBNP.

Cerebral oxygenation is associated with neurodevelopmental outcome of preterm children at age 2 to 3 years.

The aim of the study was to determine whether regional cerebral tissue oxygen saturation (r(c)SO2) and fractional tissue oxygen extraction (FTOE), using near-infrared spectroscopy, are associated with neurodevelopmental outcome of preterm infants. We measured rc SO2 on days 1, 2, 3, 4, 5, 8, and 15 after birth in 83 preterm infants (<32wks gestational age), and calculated FTOE=(SpO2 -r(c)SO2)/SpO2. Cognitive, motor, neurological, and behavioural outcomes were determined at 2 to 3 years using the Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III), an age-specific neurological examination, and the Child Behavior Checklist (CBCL) respectively. Multiple linear regression analyses were used to determine whether r(c)SO2 and FTOE contributed to outcome. We followed up 67 infants. The lower quartile (P(25-50)) and highest quartile (P(75-100)) of r(c)SO2 on day 1 were associated with poorer cognitive outcome (p=0.044 and p=0.008 respectively). A lower area under the curve (AUC; over 15d) of r(c)SO2 was associated with poorer cognitive outcome (p=0.014). The lower quartile (P(25-50)) AUC of r(c)SO2 was associated with poorer fine motor outcome (p=0.004). The amount of time r(c)SO2 <50% on day 1 was negatively associated with gross motor outcome (p=0.002). The highest quartile of FTOE on day 1 was associated with poorer total motor outcome (p=0.041). Cerebral oxygen saturation during the first 2 weeks after birth is associated with neurodevelopmental outcome of preterm infants at 2 to 3 years. High and low r(c)SO2 on day 1 were associated with poorer neurodevelopmental outcome.

Cerebral tissue oxygenation during the initiation of venovenous ECMO.

In an acute respiratory distress syndrome, venovenous extracorporeal membrane oxygenation (vvECMO) can rapidly normalize arterial hypoxemia and carbon dioxide tension (PaCO2). Considering the positive relationship between PaCO2 and cerebral blood flow, the aim of the current study was to evaluate cerebral regional tissue oxygen saturation (rSO2) during the implementation of vvECMO. Fifteen acute respiratory distress syndrome patients with recordings of cerebral rSO2 by near-infrared spectroscopy before vvECMO implementation until the optimization of the ECMO/ventilator settings were retrospectively studied. median (interquartile range). The cerebral rSO2 increased significantly (p < 0.05) from 69(61-74) to 75(60-80)% after ECMO was started, concomitant to the arterial oxygenation. Until the end of the observation period after 83(44-132) minutes, cerebral rSO2 decreased significantly to 61(52-71)%. PaCO2 decreased from 70(61-87) to 43(38-54) mm Hg and the pH increased from 7.23(7.14-7.29) to 7.39(7.34-7.43). The baseline arterial oxygen saturation and tension as well as the actual bicarbonate concentration were negatively correlated with the absolute change in cerebral rSO2 (ΔrSO2). In the 11 nonhypoxemic patients (arterial oxygen saturation ≥90%) ΔPaCO2 was significantly correlated with ΔrSO2. Patients receiving vvECMO treatment are at risk for a decrease in cerebral rSO2. This decrease is more distinct in patients with normal baseline arterial oxygenation and high actual bicarbonate.

Cerebral oxygenation measured by near-infrared spectroscopy and jugular vein oxygen saturation during robotic-assisted laparoscopic radical prostatectomy under total intravenous anaesthesia.

The effects of total intravenous anaesthesia (TIVA) on cerebral oxygenation in patients undergoing robot-assisted laparoscopic radical prostatectomy (RALP) have not been investigated. We examined the changes in jugular venous oxygen saturation (SjvO2 ) and regional cerebral tissue oxygen saturation (rSO2 ) during RALP under TIVA. Whether rSO2 could reflect SjvO2 was also examined. Forty patients (ASA 1-2) undergoing RALP were enrolled. Measurements were obtained at eight time points during the operation. SjvO2 did not decrease at any measurement point, whereas rSO2 fell significantly 120 min after pneumoperitoneum in a steep Trendelenburg position (p <0.01). There was a weak correlation between SjvO2 and rSO2 (Pearson correlation coefficient =0.34; p <0.01). Bland-Altman analysis showed a wide interval for the limit of agreement (47%) between the two measurements. These findings suggested that TIVA could be safely used for RALP. It was also demonstrated that rSO2 did not accurately reflect SjvO2 during RALP. Copyright © 2014 John Wiley & Sons, Ltd.

PS-026 Cerebral And Renal Oxygen Saturation And Extraction In Neonates With Left Ventricular Outflow Tract Obstruction

Background and aim Neonates with left ventricular outflow tract obstruction (LVOTO) are at risk of developing brain damage, due to either ischemia or hypoxemia. Our aim was to explore the differences in cerebral and renal tissue oxygen saturation (rSO 2 ) and extraction (FTOE) between neonates with LVOTO with or without compromised antegrade ascending aortic flow. Methods We included fourteen neonates with LVOTO and categorised them into neonates with compromised antegrade ascending aortic flow (hypoplastic left heart syndrome (n = 6)) and neonates without compromised antegrade ascending aortic flow (coarctatio aortae (n = 7)/non-critical aortic valve stenosis (n = 1)). We measured cerebral and renal rSO 2 using near-infrared spectroscopy during 72 h. Simultaneously, we measured preductal arterial oxygen saturation (SpO 2 ) and calculated FTOE. Results On day 1, neonates with compromised antegrade ascending aortic flow had lower cerebral rSO 2 than neonates without compromised antegrade ascending aortic flow (median rSO 2 68.5% vs. 79.4%, p-value = 0.032). Furthermore, cerebral FTOE tended to be higher in neonates with compromised antegrade ascending aortic flow on day 1 (median FTOE 0.30 vs. 0.14, p-value = 0.086). Significant differences in cerebral rSO 2 and FTOE disappeared the following days. There were no differences in SpO 2 , renal rSO 2 and FTOE between both groups. Conclusions Because there were no differences in SpO 2 between both groups, and cerebral FTOE tended to be higher in neonates with compromised antegrade ascending aortic flow, the lower cerebral oxygen saturation might be due to ischemia rather than hypoxemia. Furthermore, in neonates with antegrade ascending aortic flow, cerebral oxygenation might be spared.

PO-0509 Functional Echocardiography And Multisite Tissue Oxygenation Monitoring In Preterm Infants With Clinical Sepsis

<h3>Background</h3> Diagnosing circulatory failure in preterm infants with sepsis is challenging. Multisite Near-infrared spectroscopy (NIRS) monitoring and functional echocardiography are non-invasive tools to assess micro- and macro circulation. Our aim was to assess the correlation between both monitoring methods in preterm infants with clinical sepsis. <h3>Methods</h3> Prospective exploratory cohort study. We included preterm infants with clinical sepsis. Functional echocardiography was performed twice, once within 48 h of sepsis work-up and once at least 24 h later. We measured cerebral, renal, and intestinal tissue oxygen saturation using NIRS during an hour of stable measurements directly preceding or following echocardiography and calculated fractional tissue oxygen extraction (FTOE) in each tissue. We determined Spearman’s correlation coefficients between the FTOE and right ventricular output (RVO), left ventricular output (LVO), superior vena cava flow (SVC-flow), ductus arteriosus flow (DA-flow) and patent foramen ovale flow (PFO-flow). <h3>Results</h3> We included 24 infants (median GA=27.7 wks, BW=928g, PNA=11.8d). In seven infants only the first echocardiography was performed. Correlation coefficients between (changes in) NIRS-measurements and (changes in) functional echocardiography measurements are displayed in Table 1. <h3>Conclusion</h3> RVO-PFO and LVO-DA flow, indicators of systemic blood flow in preterm infants with shunts, were negatively associated with intestinal FTOE, but not with renal and cerebral FTOE. This indicates that a compromised macro circulation in preterm infants with clinical sepsis is associated with low intestinal but not cerebral or renal perfusion. Furthermore, our results suggest that macro circulatory changes during sepsis do not co-occur with changes in microcirculatory indices in various organs.

PO-0465 Regional Cerebral Tissue Oxygen Saturation During Neonatal Transition: Is There An Influence Of Gender?

Objective Gender definitely plays an important role for mortality and morbidity in preterm infants. Furthermore, recent studies have shown gender-specific differences favouring females with the use of supplemental oxygen during resuscitation. Female preterm infants showed less oxidative stress and increased antioxidant activity. Therefore, the aim of the present study was to investigate, whether there are differences due to gender in the course of regional cerebral tissue oxygen saturation (crSO 2 ) during transition after birth. Material and methods In a prospective observational study during 2009–2012, crSO 2 was measured using near infrared spectroscopy (NIRS) (Invos 5100 cerebral/somatic oximeter monitor; Somanetics Corp, Troy, Michigan) during the first 15 min after birth for term and preterm neonates requiring no medical support and/or supplemental oxygen. The NIRS sensor was placed on the left forehead. Peripheral oxygen saturation (SpO 2 ) and heart rate (HR) were continuously measured by pulse oximetry. Cerebral fractional oxygen extraction (cFTOE) was calculated. Data were analysed regarding gender for all study groups (term/vaginally delivered-VD term ; term/caesarean delivered-CD term ; preterm/caesarean delivered-CD preterm ). Results Out of a total of 479 measured infants during the study period, 374 were considered for further analysis. In the group of term infants, there was a gender difference in those with cesarian delivery (CD term group, n = 268): males showed significantly higher values for SpO 2 (p = . 009) and crSO 2 (p = . 009); whereas no difference was seen in HR. FTOE values were lower in males, very close to significance (p = 0.055). There was no significant difference in any parameter in vaginally delivered term infants (VD term group, n = 80), as well as in preterm infants (CD preterm group, n = 26). The power analysis showed, that in these two groups the number of infants was too small to draw significant conclusions. Conclusion There was a significant difference in course of crSO 2 and SpO 2 due to gender in term infants after cesarian section delivery, male infants did show significantly higher oxygen saturation values compared to female infants.