Differences In rSO2 Research Articles

The association of regional cerebral oximetry and neurologically intact survival in a porcine model of cardiac arrest

BackgroundThe objective of this study was to determine if regional cerebral oximetry (rSO2) assessed during CPR would be predictive of survival with favorable neurological function in a prolonged model of porcine cardiac arrest. This study also examined the relative predictive value of rSO2 and end-tidal carbon dioxide (ETCO2), separately and together. MethodsThis study is a post-hoc analysis of data from a previously published study that compared conventional CPR (C-CPR) and automated head-up positioning CPR (AHUP-CPR). Following 10 min of untreated ventricular fibrillation, 14 pigs were treated with either C-CPR (C-CPR) or AHUP-CPR. rSO2, ETCO2, and other hemodynamic parameters were measured continuously. Pigs were defibrillated after 19 min of CPR. Neurological function was assessed 24 h later. ResultsThere were 7 pigs in the neurologically intact group and 7 pigs in the poor outcomes group. Within 6 min of starting CPR, the mean difference in rSO2 by 95% confidence intervals between the groups became statistically significant (p < 0.05). The receiver operating curve for rSO2 to predict survival with favorable neurological function reached a maximal area under the curve value after 6 min of CPR (1.0). The correlation coefficient between rSO2 and ETCO2 during CPR increased towards 1.0 over time. The combined predictive value of both parameters was similar to either parameter alone. ConclusionSignificantly higher rSO2 values were observed within less than 6 min after starting CPR in the pigs that survived versus those that died. rSO2 values were highly predictive of survival with favorable neurological function.

Noninvasive Monitoring to Demonstrate Postoperative Differences in Regional Hemodynamics in Newborn Infants With d-Transposition of the Great Arteries and Hypoplastic Left Heart Syndrome.

The adequacy of tissue O2 delivery in infants receiving intensive care is difficult to measure directly. Regional O2 (rSO2) and fractional tissue O2 extraction (FTOE), the ratio of O2 consumption to O2 delivery, obtained from newer noninvasive tools, such as near-infrared spectroscopy (INVOS) and microvascular tissue oximetry (T-Stat) can provide important information on the adequacy of tissue oxygenation and aid in managing critically ill infants. We prospectively evaluated differences in rSO2 and FTOE in 26 infants with hypoplastic left heart syndrome (HLHS) (n = 12) or d-transposition of the great arteries (d-TGA) (n = 14). Continuous noninvasive monitoring of SpO2, heart rate, and perfusion index with pulse oximetry, cerebral-rSO2 and renal-rSO2 with INVOS, and buccal tissue oxygenation using T-Stat were performed during immediate postoperative period for 24 hours. The SpO2 and rSO2 in infants with d-TGA were higher compared with the infants with HLHS at all measured sites (buccal mucosa, cerebral, and renal). Significant regional differences were also observed in FTOE across all infants with the highest at the buccal mucosa tissue level, followed by cerebral and renal measurement sites. As compared with infants with d-TGA, infants with HLHS had higher regional FTOE and heart rate, with a lower arterial O2 content and perfusion index. Our study demonstrates the utility of noninvasive hemodynamic monitoring to assess regional oxygenation and perfusion, as evidenced by significant differences in infants with HLHS and d-TGA, conditions with different circulation physiologies. Such comprehensive monitoring can potentially aid in evaluating treatment strategies aimed at preventing organ damage from O2 insufficiency.

The use of 100% compared to 50% oxygen during ineffective experimental cardiopulmonary resuscitation improves brain oxygenation

IntroductionPerfusion pressure and chest compression quality are generally considered key determinants of brain oxygenation during cardiopulmonary resuscitation (CPR) and the impact of oxygen administration is less clear. We compared ventilation with 100% and 50% oxygen during ineffective manual chest compressions and hypothesized that 100% oxygen would improve brain oxygenation. MethodsVentricular fibrillation (VF) was induced electrically in anaesthetized pigs and left untreated for 5 minutes, followed by randomization to ineffective manual CPR with ventilation of 50% or 100% oxygen. The first defibrillation was performed 10 minutes after induction of VF, and CPR continued with mechanical chest compressions (LUCAS2™) and defibrillation every 2 minutes until 36 minutes or return of spontaneous circulation (ROSC). Brain oxygenation was measured with near-infrared spectroscopy (rSO2) and invasive brain tissue oxygen (PbtO2) with a probe (NEUROVENT-PTO, RAUMEDIC) inserted into frontal brain tissue. Cerebral oxygenation was compared between groups with Mann-Whitney U tests and linear mixed models. ResultsTwenty-eight pigs were included in the study: 14 subjects in each group. During ineffective chest compressions relative PbtO2 was higher in the group ventilated with 100% compared to 50% oxygen (5.2 mmHg [1.4–20.5] vs 2.2 [0.8–6.8], p = 0.001), but there was no difference in rSO2 (22% [16–28] vs 18 [15–25], p = 0.090). The use of 50% or 100% oxygen showed no difference in relative PbtO2 (p = 1.00) and rSO2 (p = 0.206) during mechanical CPR. ConclusionsThe use of 100% compared to 50% oxygen during ineffective manual CPR improved brain oxygenation measured invasively in brain tissue, but there was no difference in rSO2.

Effects on cerebral blood flow of position changes, hyperoxia, CO2 partial pressure variations and the Valsalva manoeuvre: A study in healthy volunteers.

Maintaining adequate blood pressure to ensure proper cerebral blood flow (CBF) during surgery is challenging. Induced mild hypotension, sitting position or unavoidable intra-operative circumstances such as haemorrhage, added to variations in carbon dioxide and oxygen tensions, may influence perfusion. Several of these circumstances may coincide and it is unclear how these may affect CBF. To describe the variation in transcranial Doppler and regional cerebral oxygen saturation (rSO2), as a surrogate of CBF, after cardiac preload and gravitational positional changes. Observational study. Operating room at Hospital Clínic de Barcelona. Ten healthy volunteers, white, both sexes. Measurements were performed in the supine, sitting and standing positions during hyperoxia, hypocapnia and hypercapnia protocols and after a Valsalva manoeuvre. Cardiac index (CI), haemodynamic and respiratory variables, maximal and mean velocities (Vmax, Vmean) (transcranial Doppler) and rSO2 were acquired. Results were analysed using a generalised estimating equation technique. CI increases more than 16% after a preload challenge were not accompanied by differences in rSO2 or Vmax - Vmean. With positional changes, Vmean decreased more than 7% (P = 0.042) from the supine to the seated position. Hyperoxia induced a cerebral rSO2 increase more than 6% (P = 0.0001) with decreases in Vmax, Vmean and CI values more than 3% (P = 0.001, 0.022 and 0.001) in the supine and standing position. During hypocapnia, CI rose more than 20% from supine to seated and standing (P = 0.0001) with a 4.5% decrease in cerebral rSO2 (P = 0.001) and a decrease of Vmax - Vmean more than 24% in all positions (P = 0.001). Hypercapnia increased cerebral rSO2 more than 17% (P = 0.001), Vmax - Vmean more than 30% (P = 0.001) with no changes in CI. After a Valsalva manoeuvre, rSO2 decreased more than 3% in the right hemisphere in the upright position (P = 0.001). Vmax - Vmean decreased more than 10% (P = 0.001) with no changes in CI. CBF changes in response to cerebral vasoconstriction and vasodilatation were detected with rSO2 and transcranial Doppler in healthy volunteers during cardiac preload and in different body positions. Acute hypercapnia had a greater effect on recorded brain parameters than hypocapnia.

The association between post-cardiac arrest cerebral oxygenation and survival with favorable neurological outcomes: A multicenter study

ObjectiveCerebral oximetry is a non-invasive system that uses near infrared spectroscopy to measure regional cerebral oxygenation (rSO2) in the frontal lobe of the brain. Post-cardiac arrest rSO2 may be associated with survival and neurological outcomes in out-of-hospital cardiac arrest patients; however, no studies have examined relationships between rSO2 and neurological outcomes following in-hospital cardiac arrest (IHCA). We tested the hypothesis that rSO2 following IHCA is associated with survival and favorable neurological outcomes. DesignProspective study from nine acute care hospital in the United States and United Kingdom. PatientsConvenience sample of IHCA patients admitted to the intensive care unit with post-cardiac arrest syndrome. InterventionsCerebral oximetry monitoring (Equanox 7600, Nonin Medical, MN, USA) during the first 48 h after IHCA. Measurements and Main ResultsSubject’s rSO2 was calculated as the mean of collected data at different time intervals: hourly between 1−6 h, 6−12 h, 12−18 h, 18−24 h and 24−48 h. Demographic data pertaining to possible confounding variables for rSO2 and primary outcome were collected. The primary outcome was survival with favorable neurological outcomes (cerebral performance scale [CPC] 1−2) vs severe neurological injury or death (CPC 3−5) at hospital discharge. Univariate and multivariate statistical analyses were performed to correlate cerebral oximetry values and other variables with the primary outcome. Among 87 studied patients, 26 (29.9%) achieved CPC 1−2. A significant difference in mean rSO2 was observed during hours 1−2 after IHCA in CPC 1−2 vs CPC 3−5 (73.08 vs. 66.59, p = 0.031) but not at other time intervals. There were no differences in age, Charlson comorbidity index, APACHE II scores, CPR duration, mean arterial pressure, PaO2, PaCO2, and hemoglobin levels between two groups. ConclusionsThere may be a significant physiological difference in rSO2 in the first two hours after ROSC in IHCA patients who achieve favorable neurological outcomes, however, this difference may not be clinically significant.

P1246CEREBRAL TISSUE REGIONAL OXYGEN SATURATION AND BLOOD PRESSURE IN HEMODIALYSIS PATIENTS

Abstract Background and Aims Patients undergoing hemodialysis (HD) often develop cerebral disease complications. Cerebral tissue regional oxygen saturation (rSO2) through near-infrared spectroscopy (NIRS) is a non-invasive method for cerebral tissue oxygenation monitoring. The aim of the study was to investigate the relationship between rSO2 and hemodialysis in stable HD patients. Additionally, we wanted to investigate how blood pressure during HD is associated with rSO2. Method This is a single centre cross-sectional study in clinically stable HD patients. Cerebral rSO2 was monitored at the forehead 10min before, during and 10min after HD, using an INVOS 5100C device (Medtronic, United Kingdom). Results Thirty-nine stable HD patients (23 men and 16 women; mean age, 62.4 ± 14.6 years were recruited. Dialysis vintage was 65.7 ± 72.1 months, 9 patients had diabetes mellitus, 12 had vascular disease while 14 were smokers. The baseline rSO2 levels (49.6±9.1 %) were significantly lower in HD patients compared with historic results on healthy subjects. We found no difference in rSO2 results in patients with diabetes mellitus, vascular disease or smoking. Although we found a decrease (figure) in rSO2 when patients start dialysis (10min before vs 10min after starting dialysis 49.6±9.1 vs 48.1±9.9 %, p=0.021) rSO2 value returned to baseline after dialysis (10min before vs 10min after dialysis 49.6±9.1 vs 49.9±5.9 %, p=ns. Systolic blood pressure scientifically dropped during the first hour of dialysis (146.7 ± 21.1 vs 137.3 ± 24.6, p=0.03) and systolic blood pressure drop correlated with rSO2. Three patients developed hypotensive episodes requiring iv fluids but these hypotensive episodes had no correlation with rSO2 variations. Conclusion Cerebral rSO2 decreases while patients are on dialysis but return to baseline after dialysis. Blood pressure variations correlate with rSO2 levels but rSO2 do not forecast hypotensive episodes on dialysis.

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.

Effect of Nalmefene on Delayed Neurocognitive Recovery in Elderly Patients Undergoing Video-assisted Thoracic Surgery with One Lung Ventilation.

The intravenous use of nalmefene has been found to exert neuroprotective effect in patients with severe traumatic brain injury and acute cerebral infarction; nonetheless, it is unknown whether nalmefene alleviates delayed neurocognitive recovery. Our purpose of the current research was to clarify the impact of nalmefene on delayed neurocognitive recovery in aged patients experiencing video-assisted thoracic surgery (VATS) with intraoperative use of one lung ventilation (OLV). The present study involved 120 patients undergoing selective VATS, randomized to accept low-dose nalmefene (N1 group, n=40), high-dose nalmefene (N2 group, n=40) or equal volume of physiologic saline (control group, n=40). A battery of neuropsychological tests were used to estimate cognitive function 1 day before surgery (t0) and 10 days after surgery or before discharge (t1). Regional cerebral oxygen saturation (rSO2) was detected 5 min before induction (t0), 5 min after induction (t1), 15 and 60 min after onset of OLV (t2 and t3), and 15 min after termination of OLV (t4). The plasma values of interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α and adiponectin (ADP) were also detected prior to induction of anesthesia (T0), 1 h, 2 h and 6 h after surgery (T1, T2, T3). On t1, delayed neurocognitive recovery occurred in 5/40 (12.5%) patients of N1 group, in 5/40 (12.5%) patients of N2 group and in 13/40 (32.5%) patients of control group (P0.05). There were no statistical differences in rSO2 among three groups at different time points. At T1, T2 and T3, IL-1β, IL-6 and TNF-α values significantly increased and ADP value significantly decreased (P0.05) in control group. In contrast, at T1, T2 and T3, IL-1β, IL-6 and TNF-α values decreased and ADP value decreased less in N1 and N2 groups (P0.05). At T1, T2 and T3, IL-1β, IL-6 and TNF-α concentrations presented a trend of N2 group N1 group control group and ADP presented a trend of N2 groupN1 groupcontrol group (P0.05). The result of our present research supports the hypothesis that the perioperative intravenous treatment with nalmefene to VATS with OLV ameliorates postoperative cognitive function and decreases the incidence of delayed neurocognitive recovery, most likely by suppression of inflammatory responses.

Regional cerebral oximetry is consistent across self-reported racial groups and predicts 30-day mortality in cardiac surgery: a retrospective analysis.

Darker skin pigmentation appears to cause underestimation of regional oxygen saturation (rSO2) for certain cerebral oximetry devices. This presents a risk of triggering unindicated interventions and may limit its utility for predicting adverse outcomes. Our goal was to quantify the impact of self-reported race on oximetry measurements during cardiac surgery and elucidate whether race has a mediating role in the association of rSO2 with mortality. Data was extracted from our department's data warehouse for adult patients who underwent on-pump cardiac surgery between June 2014 and June 2018. Intraoperative rSO2 was recorded every 15s throughout all cases. After grouping patients by self-reported race, multiple linear regression modeling was utilized to assess the association between race and mean pre-bypass rSO2 while controlling for various perioperative variables. The role of mean pre-bypass rSO2 for predicting 30-day mortality was evaluated via multiple logistic regression, and the threshold for rSO2 was selected by maximizing F1 score. There were 4267 patients included. Compared to Caucasian patients, the unadjusted difference in mean pre-bypass rSO2 was - 0.6% (95% CI - 1.3 to 0.04) for African American patients, - 1.8% (- 2.7 to - 0.9) for Asian patients, 0.1% (- 0.8 to 1.0) for Hispanic patients, - 1.6% (- 3.0 to - 0.4) for Indian/South Asian patients, and - 1.4% (- 3.7 to 0.9) for Pacific Islander patients. After adjusting for perioperative variables, differences in rSO2 readings less than 2% were observed between racial groups. Mean pre-bypass rSO2 under 63% was an independent predictor of higher 30-day mortality risk (OR: 2.86, CI 1.39 to 5.53, p = 0.003), and the interaction variable between rSO2 and race was not statistically significant (p = 0.299). Cerebral oximetry measurements are more consistent across racial groups than previously reported, supporting its utility for intraoperative monitoring and risk stratification. Pre-intervention rSO2 is associated with increased 30-day mortality at a higher threshold than previously reported and was not significantly impacted by self-reported race.

Effect of End-Tidal Carbon Dioxide on Cerebral Dynamics in Infants With Ventricular Septal Defect: A Comparison Between Sevoflurane and Intravenous Anesthetics

The primary aim was to compare the changes in regional cerebral oxygen saturation (rSO2) and cerebral blood flow velocity (CBFV) during sevoflurane and intravenous anesthesia when the end-tidal carbon dioxide partial pressure (PETCO2) changed in infants undergoing ventricular septal defect (VSD) repair. Prospective, observational study. Tertiary care hospital. Patients younger than 6 months with VSDs. End-tidal carbon dioxide was increased by decreasing tidal volume or respiratory rate. The infants were randomly assigned to receive either sevoflurane (SA group) or midazolam-sufentanil based intravenous anesthesia (IA group). PETCO2 levels of 30 mmHg (T1), 35 mmHg (T2), 40 mmHg (T3), or 45 mmHg (T4) were obtained by adjusting the tidal volume and respiratory rate. There were no significant intergroup differences in rSO2. In the SA group, as PETCO2 increased from T1 to T4, rSO2 increased significantly from 68.8% ± 5.9% to 76.4% ± 6.0% (p < 0.001). CBFV increased linearly, whereas the pulsatility index and resistance index decreased linearly from T1 to T4 (p < 0.001). In the IA group, rSO2 showed a significant increase from 68.6% ± 4.6% to 76.1% ± 6.2% with the change in PETCO2 from T1 to T4 (p < 0.001). CBFV increased linearly, whereas the pulsatility index and resistance index decreased linearly from T1 to T4 (p < 0.001). Cerebrovascular response to different PETCO2 levels was preserved and similar during clinically relevant doses of sevoflurane anesthesia and midazolam-sufentanil based intravenous anesthesia in infants younger than 6 months old undergoing VSD repair.

Ephedrine and phenylephrine induce opposite changes in cerebral and paraspinal tissue oxygen saturation, measured with near-infrared spectroscopy: a randomized controlled trial.

While the effects of phenylephrine (PE) and ephedrine (E) on cerebral oxygen saturation (rScO2) already has been studied, the effect on paraspinal oxygen saturation (rSpsO2) is still unexplored. This study aims to assess the effect of PE and E on rScO2 and rSpsO2, measured with near-infrared spectroscopy. A randomized 4-treatment cross-over trial was designed in 28 patients under BIS-titrated anaesthesia with sevoflurane. If MAP decreased more than 20% from baseline, incremental doses of PE and/or E were given according to the randomization (group I: E-PE-E, group II: PE-E-PE, group III: E-E-E, group IV: PE-PE-PE). rScO2 and rSpsO2 on T3-T4, T9-T10 and L1-L2 were recorded. Differences in rSO2 (post-pretreatment) within each group were analyzed with paired Student's t test. Differences in effects of PE and E on rScO2 and rSpsO2 were analyzed with linear mixed-modelling. Following PE administration, rScO2 decreased significantly (- 2.7% ± 3.5), while it remained stable following E (- 0.6% ± 3.6). Contrastingly, rSpsO2 at T3-T4, T9-T10 and L1-L2 slightly increased following PE (0.4% ± 2.5, 0.7% ± 2.0 and - 0.1% ± 1.4, respectively), while it decreased after E administration (- 1.3% ± 3.4%, - 0.7% ± 2.6% and - 1.3% ± 2.7%, respectively). Compared to E, PE administration was associated with a significant decrease in rScO2 (- 2.1%, 95% CI [- 3.1%, - 1.2%], p < 0.001). In contrast, compared to PE, E was associated with a significant decrease in rSpsO2 at T3-T4, T9-T10 and L1-L2 (- 2.0%, 95% CI [- 2.8, - 1.1], p < 0.001; - 1.4%, 95% CI [- 2.4%, - 0.4%], p = 0.006; and - 1.5%, 95% CI [- 2.3%, - 0.8%], p < 0.001, respectively). An opposite effect on rScO2 and rSpsO2 was observed after bolus administration of PE and E.

Utility of a Finger-Mounted Tissue Oximeter with Near-Infrared Spectroscopy to Evaluate Limb Ischemia in Patients with Peripheral Arterial Disease.

Objective: To investigate whether a finger-mounted tissue oximeter is useful in evaluating limb blood flow in patients with peripheral arterial disease (PAD).Materials and Methods: Seventy-two patients with PAD were included, and the ankle-brachial index (ABI), transcutaneous oxygen pressure (TcPO2), and skin perfusion pressure (SPP) were measured. The regional tissue oxygenation saturation (rSO2) was measured using a finger-mounted tissue oximeter at the ankle, dorsal foot, and each dorsal and plantar toe. Correlations between rSO2 and ABI and between TcPO2 and SPP were analyzed. The patients were divided into three groups: Fontaine IIa (F-IIa), IIb (F-IIb), and III and IV (F-III/IV) groups. The difference in rSO2 between each group was analyzed.Results: Significant correlations were observed between rSO2 and TcPO2 and between rSO2 and SPP. TcPO2 and SPP in the F-III/IV group were significantly lower than those in the F-IIa group. rSO2 in the F-IIb and F-III/IV groups was significantly lower than that in the F-IIa group.Conclusion: The measurement of rSO2 using finger-mounted tissue oximetry is quick, simple, and painless. It can be used on any skin area and is useful to evaluate limb circulation in patients with PAD.

Vasopressor Infusion After Subarachnoid Hemorrhage Does Not Increase Regional Cerebral Tissue Oxygenation.

Vasopressors are commonly used after aneurysmal subarachnoid hemorrhage (aSAH) to sustain cerebral pressure gradients. Yet, the relationship between vasopressors and the degree of cerebral microcirculatory support achieved remains unclear. This study aimed to explore the changes in cerebral and peripheral regional tissue oxygen saturation (rSO2) as well as blood pressure (BP) before and after vasopressor infusion in patients with aSAH. Continuous noninvasive cerebral and peripheral rSO2 was obtained using near-infrared spectroscopy for up to 14 days after aSAH. Within-subject differences in rSO2 before and after the commencement of vasopressor infusion were analyzed controlling for Hunt and Hess grade and vasospasm. Of 45 patients with continuous rSO2 monitoring, 19 (42%) received vasopressor infusion (all 19 on norepinephrine, plus epinephrine in 2 patients, phenylephrine in 4 patients, and vasopressin in 2 patients). In these 19 patients, their vasopressor infusion times were associated with higher BP (systolic [b = 15.1], diastolic [b = 7.3], and mean [b = 10.1]; P = .001) but lower cerebral rSO2 (left cerebral rSO2 decreased by 4.4% [b = -4.4, P < .0001]; right cerebral rSO2 decreased by 5.5% [b = -5.5, P = .0002]). Despite elevation in systemic BP during vasopressor infusion times, cerebral rSO2 was concurrently diminished. These findings warrant further investigation for the effect of induced hypertension on cerebral microcirculation.

Decreased tissue oxygenation in newborns with congenital heart defects: a case-control study.

AimTo compare regional tissue oxygenation (rSO2) in the brain, intestine, and kidney between newborns with and without congenital heart defects (CHD).MethodsThis observational case-control study was conducted at the Neonatal Deparetment of Children's Hospital Ljubljana between December 2012 and April 2014. It included 35 newborns with CHD and 30 healthy age- and sex-matched controls. CHD were assessed echocardiographically and divided into acyanotic and cyanotic group. RSO2 in the brain, intestine, and kidney was measured using near-infrared spectroscopy (NIRS). Simultaneously, heart rate (HR), breathing frequency (BF), mean arterial blood pressure (MAP), and arterial oxygen saturation (Sao2) were recorded.ResultsNewborns with CHD had significantly lower rSO2 in the left brain hemisphere (67 ± 11% vs 76 ± 8%, P = 0.004), right brain hemisphere (68 ± 11% vs 77 ± 8%, P < 0.001), and the kidney (68 ± 13% vs 77 ± 10%, P = 0.015). RSO2 in the intestine did not significantly differ between the groups. HR, MAP, and Sao2 also did not differ between the groups, whereas BF was significantly higher in the CHD group (57 ± 12 vs 39 ± 10 breaths/min, P < 0.001). Between cyanotic and acyanotic group, we found no significant differences in rSO2 of any tissue.ConclusionsMonitoring tissue oxygenation by NIRS could enable a timely detection of hemodynamically important CHD.

Effects of ultrasound-guided stellate-ganglion block on sleep and regional cerebral oxygen saturation in patients undergoing breast cancer surgery: a randomized, controlled, double-blinded trial.

Numerous factors could contribute to sleep disturbances in women with breast cancer. We hypothesized that stellate ganglion block (SGB) during surgery would preserve sleep after surgery and increase intraoperative regional cerebral oxygen saturation (rSO2) on the blocked side in patients undergoing breast cancer surgery. A randomized, double-blinded, controlled trial was conducted at the First Hospital of China Medical University from January 2016 to September 2016. Ninety-six patients who underwent radical breast cancer surgery requiring general anaesthesia were randomly assigned to one of two study groups: a control group that received a saline SGB and a block group that received a 0.25% ropivacaine hydrochloride SGB. The primary outcome measure was the postoperative sleep profile, which was assessed using the bispectral index on the first postoperative night. The secondary outcome measure was the intraoperative rSO2, monitored was throughout surgery using near-infrared spectroscopy. A total of 91 female patients (mean age: 45years; range 24-51years) were included in the study. The duration of sleep was significantly increased by 66.3min in the ropivacaine-SGB group compared with the saline-SGB group. No differences in rSO2 were observed on either the left or right side of the patients in either group 50min after anaesthesia induction. We conclude that ropivacaine-SGB combined with general anaesthesia might increase the first postoperative sleep duration without influencing the intraoperative rSO2 in female patients undergoing elective breast cancer surgery. Clinical trials.gov identifier NCT02651519.

Differences in tissue oxygenation and changes in total hemoglobin signal strength in the brain, liver, and lower-limb muscle during hemodialysis.

Near-infrared spectroscopy has been used to measure regional saturation of oxygen (rSO2) based on the total hemoglobin (t-Hb) signal strength. To date, few studies have investigated the changes of systemic oxygenation and t-Hb signal strength during hemodialysis (HD). This study aimed to (1) monitor rSO2 and t-Hb signal strength in the brain, liver, and lower-limb muscle during HD and (2) clarify the differences in rSO2 and t-Hb signal strength in each compartment. Fifty-three patients receiving 4-h HD were included and divided into three groups according to the compartments in which tissue oxygenation was measured as follows: brain (n=44), liver (n=42), and lower-limb muscle (n=40). The rSO2 and t-Hb signal strength was monitored using an INVOS 5100c (Covidien Japan, Tokyo, Japan). The rSO2 levels were significantly lower in the brain than in the liver from HD initiation to the end (HD initiation: rSO2 in the brain and liver, 46.5±1.3 and 52.4±1.7%, respectively, p=0.031). Furthermore, compared to the t-Hb signal strength ratio [value at t (min) during HD/initial value before HD] in the brain during HD, there were significant increases in the liver and lower-limb muscle, respectively. In conclusion, deterioration of cerebral oxygenation was remarkable compared to the hepatic oxygenation in HD patients. Our results, which revealed significant differences among the t-Hb signal strength ratios in the brain, liver, and lower-limb muscle during HD, might reflect the non-uniform body-fluid reduction within systemic tissues induced by ultrafiltration.

The effect of the beach-chair position angle on cerebral oxygenation during shoulder surgery

Although the safety of the beach-chair position (BCP) is widely accepted, rare devastating neurologic complications have been reported and attributed to cerebral hypoperfusion. Cerebral oxygenation (regionaloxygensaturation [rSO2]) can be monitored noninvasively using near-infrared spectroscopy. The purpose of this study was to determine the effect of BCP angle on cerebral oxygenation in patients undergoing shoulder surgery in the BCP. Fifty patients undergoing shoulder arthroscopy were prospectively enrolled to participate. Following induction of general anesthesia, each patient's rSO2 was recorded at 0° of elevation and again at 30°, 45°, 60°, and 80° of elevation. Mean rSO2 values and mean differences in rSO2 were reported. An average total decrease of 5% in rSO2 was seen when comparing 0° with 80° (P < .001). There were statistically significant differences in rSO2 values at beach-chair angles of 0° versus 30° (P <.001), 30° versus 45° (P = .007), and 45° versus 60° (P <.001) but not between 60° and 80° (P = .12). The decrease in rSO2 was similar between each progressive increase in the beach-chair angle, leading to a linear decline in rSO2 as the BCP increased (regression slope of -0.060%/°, P <.001). No patient's cerebral oxygenation dropped greater than 20% from baseline. Neither body mass index nor American Society of Anesthesiologists score had a significant impact on the relation of rSO2 to BCP angle. The average drop in rSO2 is significantly less than the threshold of 20% used as an identifier for a cerebral deoxygenation event. This study illustrates the direct effect the BCP angle has on cerebral oxygenation.

Relationship between intraoperative regional cerebral oxygen saturation trends and cognitive decline after total knee replacement: a post-hoc analysis

BackgroundBilateral regional brain oxygen saturation (rSO2) trends, reflecting intraoperative brain oxygen imbalance, could warn of brain dysfunction. Various types of cognitive impairment, such as memory decline, alterations in executive function or subjective complaints, have been described three months after surgery. Our aim was to explore the potential utility of rSO2 values as a warning sign for the development of different types of decline in postoperative psychological function.MethodsObservational post-hoc analysis of data for the patient sample (n = 125) of a previously conducted clinical trial in patients over the age of 65 years undergoing total knee replacement under spinal anesthesia. Demographic, hemodynamic and bilateral rSO2 intraoperative values were recorded. An absolute rSO2 value of <50% or a reduction of >20% or >25% below baseline were chosen as relevant cutoffs. Composite function test scores were created from baseline to three months for each patient and adjusted for the mean (SD) score changes for a control group (n = 55). Tests were used to assess visual-motor coordination and executive function (VM-EF) (Wechsler Digit Symbol-Coding and Visual Reproduction, Trail Making Test) and memory (Auditory Verbal Learning, Wechsler Memory Scale); scales were used to assess psychological symptoms.ResultsWe observed no differences in baseline rSO2 values; rSO2 decreased significantly in all patients during surgery (P < 0.0001). Seventy-five patients (60%) had no sign of cognitive decline or psychological symptoms. Twenty-one patients (16.8%) had memory decline, 3 (2.4%) had VM-EF decline, and 33 (26.4%) had psychological symptoms. Left and right rSO2 values were asymmetric in patients who had memory decline (mean [SD] left-right ratio of 95.03 [8.51] vs 101.29 [6.7] for patients with no changes, P = 0.0012). The mean right-left difference in rSO2 was also significant in these patients (-2.87% [4.73%], lower on the right, P = 0.0034).ConclusionsDetection of a trend to asymmetry in rSO2 values can warn of possible postoperative onset of memory decline. Psychological symptoms and memory decline were common three months after knee replacement in our patients over the age of 65 years.

Abstract 278: A Pilot Study Examining the Role of Regional Cerebral Oxygen Saturation Monitoring as a Marker of Return of Spontaneous Circulation in the Shockable and Nonshockable Causes of Cardiac Arrest

Background: To date there has been no reliable “real time” monitoring available to determine the adequacy of oxygen delivery and cerebral perfusion during cardiac arrest. Although, we have previously demonstrated that the mean regional cerebral oxygen saturation (rSO2) measured by cerebral oximetry can be used to determine return of spontaneous circulation in cardiac arrest, the rSO2 level that corresponds with ROSC in the 3 main different subtypes of cardiac arrest (VF/VT, PEA, asystole has not been examined. Objectives: To investigate the level of rSO2 that corresponds with ROSC in 1) VF/VT, 2) PEA and 3) asystole subtypes of cardiac arrest using a commercially available cerebral oximeter (Equanox, Nonin, USA) Methods: Cerebral oximetry was applied to 34 in-hospital cardiac arrest patients and continuous data was collected until either ROSC was achieved or CPR was terminated. Results: Overall 20 patients achieved ROSC, whereas 14 did not. There was a significant overall difference in mean±SD rSO2% in patients who achieved ROSC (49.7 ± 11.3% vs. 33.9 ± 15.0% p=&lt;0.001) compared to those who did not. Examination of the cardiac arrest subtypes revealed that while this difference was observed in the PEA (n=13) 54.6 ± 8.7 vs. 36.8 ± 20.4 (p=&lt;0.05) and asystole (n=16) 46.6 ± 11.4 vs. 27.4 ± 10.8 (p=&lt;0.05) subgroups, there was no difference in rSO2 in patients with and without ROSC in the VF/VT subgroup (n=5) 41.6 ± 18.5 vs. 45.0 ± 11.6 (p=0.8). Conclusions : Although cerebral oximetry may be used as a real-time non-invasive marker of ROSC during cardiac arrest, the main difference in rSO2 between patients achieving ROSC and those without ROSC applies to the asystole and PEA sub groups of cardiac arrest, rather than VF/VT. This likely reflects the different dominant physiological disorders between shockable and non-shockable causes of cardiac arrest. Whereas recovery from PEA and asystole is dependent on the adequacy of oxygen delivery, recovery from VF/VT predominantly relates to the timing of defibrillation.

Mortality and Regional Oxygen Saturation Index in Septic Shock Patients: A Pilot Study

Peripheral muscle tissue oxygenation determined noninvasively using near-infrared spectroscopy may help to identify tissue hypoperfusion in septic patients. The aim of this study was to investigate regional oxygen saturation index (rSO2) in the brachioradialis (forearm) muscle by comparing measurements in healthy subjects and in intensive care unit (ICU) septic shock patients, and determine whether brachioradialis muscle rSO2 is associated with poor outcome in ICU septic shock patients. We conducted a prospective observational study in healthy volunteers (n = 50) and ICU septic shock patients (n=19). Brachioradialis (forearm) rSO2 measurements in healthy volunteers at rest and in ICU septic shock patients were compared. Pulmonary artery catheter monitoring was used in ICU patients. Significant differences in rSO2 were observed between healthy volunteers and ICU septic shock patients at ICU admission (68.7±4.9 vs. 55.0±13.0; p<0.001). When comparing septic shock survivors and nonsurvivors, significant differences were observed in rSO2 at baseline (64.5±8.9 vs. 47.5±10.7; p<0.01), 12 hours (67.3±9.6 vs. 45.0±14.9; p<0.01), and 24 hours (65.7±7.0 vs. 50.1±10.3; p<0.01). Lactate concentration was lower in survivors than nonsurvivors at 24 hours (12.0±7.5 mmol/L vs. 23.2±12.5 mmol/L; p<0.04). Cardiac index was greater in nonsurvivors than survivors at baseline (4.6+1.9 L/min/m vs. 3.0+0.9 L/min/m; p<0.05) and 12 h (3.9+0.5 L/min/m vs. 3.1+0.3 L/min/m; p<0.05). We observed that septic shock patients with forearm skeletal muscle rSO2≤60% throughout first 24 hours after ICU admission had significantly greater mortality rate than patients with forearm skeletal muscle rSO2>60% throughout this critical time.