Decrease In Cerebral Oxygen Saturation Research Articles

Effect of oxygen supplementation on cognitive performance among HEMS providers after acute exposure to altitude: the HEMS II randomized clinical trial

ImportanceEmergency medical services (EMS) providers transiently ascend to high altitude for primary missions and secondary transports in mountainous areas in helicopters that are unpressurised and do not have facilities for oxygen supplementation. The decrease in cerebral oxygen saturation can lead to impairment in attention and reaction time as well as in quality of care during acute exposure to altitude.ObjectiveThe primary aim of the current study was to investigate the effect of oxygen supplementation on cognitive performance in Helicopter EMS (HEMS) providers during acute exposure to altitude.Design, setting, and participantsThis interventional, randomized, controlled, double-blind, cross-over clinical trial was conducted in October 2021. Each trial used a simulated altitude scenario equivalent to 4000 m, in which volunteers were exposed to hypobaric hypoxia with a constant rate of ascent of 4 m/s in an environmental chamber under controlled, replicable, and safe conditions. Trials could be voluntarily terminated at any time. Inclusion criteria were being members of emergency medical services and search and rescue services with an age between 18 and 60 years and an American Society of Anesthesiologists physical status class I.ExposuresEach participant conducted 2 trials, one in which they were exposed to altitude with oxygen supplementation (intervention trial) and the other in which they were exposed to altitude with ambient air supplementation (control trial).Main outcomes and measuresMeasurements included peripheral oxygen saturation (SpO2), cerebral oxygenation (ScO2), breathing and heart rates, Psychomotor Vigilance Test (PVT), Digit-Symbol Substitution Test (DSST), n-Back test (2-BACK), the Grooved Pegboard test, and questionnaires on subjective performance, stress, workload, and positive and negative affect. Paired t-tests were used to compare conditions (intervention vs. control). Data were further analyzed using generalized estimating equations (GEE).ResultsA total of 36 volunteers (30 men; mean [SD] age, 36 [9] years; mean [SD] education, 17 [4] years) were exposed to the intervention and control trials. The intervention trials, compared with the control trials, had higher values of SpO2 (mean [SD], 97.9 [1.6] % vs. 86 [2.3] %, t-test, p = 0.004) and ScO2 (mean [SD], 69.9 [5.8] % vs. 62.1 [5.2] %, paired t-test, p = 0.004). The intervention trials compared with the control trials had a shorter reaction time (RT) on the PVT after 5 min (mean [SD], 277.8 [16.7] ms vs. 282.5 [15.3] ms, paired t-test, p = 0.006) and after 30 min (mean [SD], 276.9 [17.7] ms vs. 280.7 [15.0] ms, paired t-test, p = 0.054) at altitude. While controlling for other variables, there was a RT increase of 0.37 ms for each % of SpO2 decrease. The intervention trials showed significantly higher values for DSST number of correct responses (with a difference of mean [SD], 1.2 [3.2], paired t-test, p = 0.035). Variables in the intervention trials were otherwise similar to those in the control trials for DSST number of incorrect responses, 2-BACK, and the Grooved Pegboard test.Conclusions and relevanceThis randomized clinical trial found that oxygen supplementation improves cognitive performance among HEMS providers during acute exposure to 4000 m altitude. The use of oxygen supplementation may allow to maintain attention and timely reaction in HEMS providers. The impact of repeated altitude ascents on the same day, sleep-deprivation, and additional stressors should be investigated.Trial registration NCT05073406, ClinicalTrials.gov trial registration.

Electroencephalography as a tool to predict cerebral oxygen metabolism during deep-hypothermic circulatory arrest in neonates with critical congenital heart disease

ObjectivesRecent research suggests that increased cerebral oxygen use during surgical intervention for neonates with congenital heart disease may play a role in the development of postoperative white matter injury. The objective of this study is to determine whether increased cerebral electrical activity correlates with greater decrease of cerebral oxygen saturation during deep hypothermic circulatory arrest. MethodsNeonates with critical congenital heart disease requiring surgical intervention during the first week of life were studied. All subjects had continuous neuromonitoring with electroencephalography and an optical probe (to quantify cerebral oxygen saturation) during cardiac surgical repair that involved the use of cardiopulmonary bypass and deep hypothermic circulatory arrest. A simple linear regression was used to investigate the association between electroencephalography metrics before the deep hypothermic circulatory arrest period and the change in cerebral oxygen saturation during the deep hypothermic circulatory arrest period. ResultsSixteen neonates had both neuromonitoring modalities attached during surgical repair. Cerebral oxygen saturation data from 5 subjects were excluded due to poor data quality, yielding a total sample of 11 neonates. A simple linear regression model found that the presence of electroencephalography activity at the end of cooling is positively associated with the decrease in cerebral oxygen saturation that occurs during deep hypothermic circulatory arrest (P < .05). ConclusionsElectroencephalography characteristics within 5 minutes before the initiation of deep hypothermic circulatory arrest may be useful in predicting the decrease in cerebral oxygen saturation that occurs during deep hypothermic circulatory arrest. Electroencephalography may be an important tool for guiding cooling and the initiation of circulatory arrest to potentially decrease the prevalence of new white matter injury in neonates with critical congenital heart disease.

The Effects of Carotid Endarterectomy Surgery on Cerebral Oxygenation, Randomized Clinical Trial

Purpose: The aim of this study is to assess how NIRS values changed with cross-clamp (CC) duration in carotis endarterectomy (CEA) surgeries. Materials and Methods: The study included 30 patients. Before induction of general anesthesia, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), peripheral oxygen saturation (SpO 2 ), and regional oxygen saturation(rSO 2 ) values were recorded as right and left sides. The same parameters were recorded before the carotid CC, at the 3rd, 5th, and 10th minutes of the carotid CC, and at the 1st and 5th minutes after the cross-clamp removal postoperatively. Results: When the rSO 2 values of the study participants were measured at different times, there was a significant difference (p<0.05) between the right-sided mean rSO 2 values of the patients who underwent right-sided surgery (n=11). There was also a significant difference (p<0.05) between the left-sided mean rSO 2 values of the patients who underwent left-sided surgery (n=19). Conclusion: We discovered that there was a significant decrease in cerebral oxygen saturation during CC in patients who had CEA surgery under general anesthesia and that cerebral oxygen saturation reached or exceeded the basal value after the CC was opened.

Intraoperative cerebral oxygen saturation and neurological outcomes following surgical management of necrotizing enterocolitis: Predictive factors of neurological complications following neonatal necrotizing enterocolitis: Predictive factors of neurological complications following neonatal necrotizing enterocolitis.

The goal of the present study was to investigate intraoperative factors associated with major neurological complications at 1year following surgery for necrotizing enterocolitis. The study consisted of a retrospective review of medical charts of patients operated for over one calendar year in one institution. Data collected included demographic data, cardiac resuscitation at birth, Bell classification, antibiotics usage, time of day of surgery, surgical technique, surgical duration, type of ventilation, intraoperative vasoactive agents, and albumin use, nadir cerebral saturation, the decrease in cerebral saturation from baseline, the time period when cerebral saturation was at least 20% below baseline, and the mean arterial pressure at nadir cerebral saturation. Reported follow-up complications were assessed during formal neonatologist consultation and additional imaging exploration as needed. Analyses included descriptive statistics, and univariable and multivariable statistics. The study included 32 patients with no prior clinical neurological complications, of which 25had normal cerebral imaging. Severe neurological complications occurred in nine patients at 1year: Intraventricular hemorrhage (N=2) and Periventricular leukomalacia (N=7). However, preoperative cerebral imaging was lacking in seven patients. Consequently, the observed neurological complications at 1year might be present before the surgery. Multivariable analysis found the decrease in cerebral saturation ≥36% from baseline as the only factor associated with the occurrence of those complications. Intraoperative decrease of cerebral oxygen saturation below ≥36% from baseline is associated with severe neurological complications in neonates undergoing surgery for necrotizing enterocolitis.

Effect of hemoglobin content on cerebral oxygen saturation during surgery for scoliosis in pediatric patients

BackgroundAlthough regional cerebral oxygen saturation (rScO2) monitoring has been widely used in clinical practice, the relationship between hemoglobin (dHB) content and rScO2 is incompletely understood. The aim of this study was to analyze the effect of hemoglobin content on rScO2 in pediatric patients undergoing general anesthesia for correction of scoliosis.MethodsNinety-two pediatric patients aged 3 to 14 years undergoing scoliosis correction surgery were enrolled. Continuous monitoring of bilateral regional cerebral oxygen saturation by near-infrared spectroscopy (NIRS, CASMED, USA) was performed after entering the operation room. rScO2 was recorded when the patients entered the operating room (T0, baseline), after anesthesia induced intubation (T1), and after radial artery puncture (T2). The lowest value of rScO2 during surgery was also recorded. The arterial blood pressure (ABP), heart rate (HR), pulse oxygen saturation (SpO2), end tidal carbon dioxide partial pressure (PetCO2) were continuously recorded. Patients were classified as low rScO2 or high rScO2 group according to whether the lowest intraoperative rScO2 was 15% lower than the baseline value. An analysis and comparison of differences in hemoglobin content in these two groups was carried out.ResultsThe preoperative hemoglobin-postoperative hemoglobin of patients in the high rScO2 group was significantly lower than that in the low rScO2 group (t = − 7.86, p < 0.01), the amount of bleeding during the operation was also less than that in the low rScO2 group (t = − 6.05, p < 0.01), and the systolic pressure of patients was higher than that in the low rScO2 group (t = 4.27, p < 0.01).ConclusionsThe decrease in hemoglobin level which occurs during surgery leads to a decrease in cerebral oxygen saturation. In order to ensure patient safety during surgery, it is necessary to carry out volume management and appropriate transfusion and fluid replacement in a timely manner.Trial registrationChinese Clinical Trial Registry, ChiCTR1800016359. Registered 28 May 2018.

The hidden consequence of intraventricular hemorrhage: persistent cerebral desaturation after IVH in preterm infants.

Background:Previous studies describe a short-term decrease in cerebral oxygen saturation (StO2) after intraventricular hemorrhage (IVH) in premature infants; little is known about long-term implications.Methods:Infants born <30 weeks gestational age (GA) were included. Clinical characteristics, hemoglobin measurements, highest grade of IVH, and white matter injury (WMI) were noted.NIRS monitoring occurred daily or every other day for four weeks; weekly through 36 weeks GA. Recordings were error-corrected before calculation of mean StO2 and fractional tissue oxygen extraction (FTOE). Mean StO2 and FTOE were plotted by postnatal age and injury group (IVH/no IVH; WMI/no WMI). Non-linear regression by locally-estimated scatterplot smoothing was used to generate the best-fit line and CI.Results:1237 recordings from 185 infants were included; mean length=6.5h; mean GA=26.3w; mean BW=951g; overall/severe IVH incidence was 29/8%, WMI incidence was 16%. IVH was independently associated with an acute drop in StO2 which remained lower for 68d. Severe IVH was associated with lower StO2 values than mild IVH. WMI was associated with early and persistent elevation of FTOE.Conclusion:IVH of any grade is associated with a prolonged cerebral desaturation, WMI is associated with prolonged elevation of FTOE. This finding is exacerbated for infants with severe IVH.

Decrease in Cerebral Oxygen Saturation During the 6-Minute Walk Test in Pediatric Pulmonary Arterial Hypertension.

This observational study aimed to investigate the relationship between regional cerebral oxygen saturation (rSO2) during the 6-minute walk test (6-MWT) and the demographic/clinical features of patients with pulmonary arterial hypertension (PAH). Cerebral oxygenation was evaluated during the 6-MWT in 20 pediatric patients with PAH aged ≥ 7years [13 male, 7 female; median age 12.25 (range 7-18) years]. In all patients, regional cerebral oxygen saturation (rSO2), arterial oxygen saturation (SpO2), and heart rate (HR) were measured using near-infrared spectroscopy (NIRS) for 2min before the test, during the 6-MWT test, and 2min after the test. The relationship between the changes in rSO2, heart rate, and SpO2 values and clinical and laboratory features was compared statistically. The mean pulmonary arterial pressure (mPAP) was 77 (range 25-126) mmHg, and the median 6-minute walk distance (6-MWD) was 427.5 (300-570) m. The changes in rSO2 measurements ranged between 3.41 and 21.8%, and 70% of the patients had a greater than 10% decrease in rSO2 during the test compared with baseline. Eight patients showed a decrease in rSO2 without SpO2 changes. The present study demonstrated a significant decrease in cerebral oxygenation in pediatric patients with PAH during the 6-MWT. We hypothesized that using a combination of the 6-MWT and regional cerebral oxygenation monitoring in pediatric patients with PAH in order to evaluate exercise capacity, as a reflection of reduced daily activities, would provide more precise predictive values than the 6-MWT alone.

Pencil Beam Presaturation Magnetic Resonance Imaging Helps to Identify Patients at Risk for Intolerance to Temporary Internal Carotid Artery Occlusion During Carotid Endarterectomy and Carotid Artery Stenting

There has been no effective method to predict ischemic intolerance to temporary internal carotid artery (ICA) occlusion during carotid artery reconstruction. Pencil beam presaturation (BeamSAT) pulse suppresses the flow signal of the target vessel in magnetic resonance angiography (MRA). Applying this method, we constructed ICA-selective MRA images. The aim of this study was to identify patients at risk for ischemic intolerance by ICA-selective MRA. By evaluating flow of anterior communicating artery (Acom) and A1 portion of anterior cerebral artery with ICA-selective MRA and posterior communicating artery (Pcom) with conventional MRA, we investigated associations of these collateral flow patterns with ischemic intolerance and decrease of regional cerebral oxygen saturation. The study included 58 patients who underwent carotid endarterectomy or carotid artery stenting. Six of 7 patients without Acom flow and Pcom flow demonstrated ischemic intolerance, whereas all patients (n= 51) with Acom and/or Pcom flow demonstrated tolerance. The accuracy of this prediction model according to Acom and Pcom flow patterns for ischemic intolerance was 0.98 (P=0.01, binomial test). Regional cerebral oxygen saturation decrease after ICA occlusion was significantly larger in patients without Acom flow and Pcom flow (12.0%± 6.0%) than in patients with Acom flow and Pcom flow (3.0% ± 3.1%, P < 0.01) and in patients with Acom flow but no Pcom flow (2.4% ± 5.2%, P < 0.01). These findings support the importance of Acom flow as a collateral route. ICA-selective MRA enables prediction of ischemic intolerance to temporary ICA occlusion during carotid endarterectomy or carotid artery stenting. This method provides valuable information regarding probability of an ischemic complication.

Cerebral Oxygenation Under General Anesthesia Can Be Safely Preserved in Patients in Prone Position: A Prospective Observational Study.

The effects of prone position (PP) on cerebral tissue metabolism are not well known. The aim of this investigation was to evaluate regional cerebral oxygen desaturation in patients undergoing lumbar spine surgery in PP during routine anesthesia management. Between July 2013 and October 2013, 50 consecutive patients undergoing lumbar spine surgery under general anesthesia in PP were enrolled. The anesthetic technique was standardized. Using near-infrared spectroscopy, bilateral regional cerebrovascular oxygen saturation was recorded during the surgery. After 30 and 60 minutes of prone repositioning, significant decreases in bilateral regional cerebral oxygen saturation were observed compared with the values in the supine position (from 76.24% to 73.18% at 30 min and 72.76% at 60 min on the right side and from 77.06% to 73.76% at 30 min and 72.92% at 60 min on the left side; P<0.05). These changes were not clinically important and returned to supine values after 90 minutes of prone positioning. Decreases in cerebral oxygen saturation were accompanied by reductions in heart rate and mean arterial pressure (P<0.05). Older age and higher perioperative risk had a significant effect on the reduction of cerebral oxygen values (P<0.05). The results of our study show that margin of safety against impaired cerebral oxygenation can be maintained in PP. Preventing bradycardia and arterial hypotension is crucial. Older patients and those at higher perioperative risk need more meticulous attention.

Does the degree of beach chair position during shoulder arthroscopy affect cerebral oxygenation? A prospective comparative study

Background: The aim of this prospective cohort study was to determine the incidence of cerebral desaturation events (CDE) in patients undergoing shoulder arthroscopy in the beach chair position (BCP) compared to patients undergoing shoulder arthroscopy in the semi-upright sitting position (SSP). Methods: This prospective study included 220 patients, 150 men (68.18%) and 70 women (31.82%). The average age was 46 yr (24-68) years. Patients under 18 yr of age, those with uncontrolled diabetes, a previous cerebral stroke, a myocardial infarction, rheumatoid arthritis, congestive heart failure, severe cervical disc prolapsed, or severe obesity (body mass index &gt;30) were excluded from the study. The patients were divided into two groups (110 patients in each group). Group A patients had shoulder arthroscopy done in the 60-degree beach chair position and Group B had shoulder arthroscopy done in a semi-upright sitting position at 90 degrees. Mean arterial blood pressure and cerebral oxygen saturation were measured at different stages: before induction of anesthesia (T0), after induction (T1 [baseline]), after positioning (T2), after induction of hypotension (T3), and 1 hr after final position (T4). Cerebral desaturation was defined as a reduction in regional cerebral oxygen saturation to less than 80% of baseline value for 15 sec or longer. Each stage was compared with others in the same group and with the other group. Results: In both groups, the mean arterial blood pressure (MAP) values at T2 were significantly lower than at T1. The MAP values at T3 and T4 were significantly lower than those at T1 and T2. There was a significant decrease in regional cerebral oxygen saturation in stage T3 when compared to previous stages in the same group. Without any significant decrease in stage T4 compared to T3 in the same group. We found no significant difference in regional cerebral oxygen saturation when comparing each stage in both groups. Conclusions: No significant difference was noted in regional cerebral oxygen saturation between patients operated on in the beach chair position and those operated on in the semi-upright sitting position. A direct relation was noted between the decrease in mean arterial pressure and decrease in cerebral oxygen saturation.

Decrease in cerebral oxygen saturation with phenylephrine indicates a functional cerebral autoregulation mechanism

Decrease in cerebral oxygen saturation with phenylephrine indicates a functional cerebral autoregulation mechanism

Acute decrease of cerebral oxygen saturation during rapid ventricular and supraventricular rhythm: a pilot study.

Monitoring of cerebral tissue oxygen saturation (SctO2 ) reflects cerebral microcirculation. We sought to characterize the decrease in SctO2 during supraventricular tachycardia (SVT) and ventricular tachycardia (VT) in adults. Twenty patients (mean age: 46.3 ± 18.1 years, 40% men) were included. Rapid atrial and ventricular pacing (200/min) was used as a model for VT and SVT. Near-infrared spectroscopy (NIRS) was used to measure SctO2 . Atrial stimulation decreased right (P = 0.014) and left (P = 0.019) hemispheric SctO2 compared to baseline. Ventricular stimulation also decreased right (P < 0.001) and left (P < 0.001) hemispheric SctO2 . A negative correlation between age and minimal value under stimulation was found for atrial (right SctO2 r = -0.641, P = 0.034; left SctO2 r = -0.694, P = 0.018) and ventricular pacing (right SctO2 r = -0.564, P = 0.01; left SctO2 r = -0.604, P = 0.005). A positive correlation was found between left ventricular ejection fraction (LVEF) and minimal value under ventricular stimulation (right SctO2 r = 0.567, P = 0.009; left SctO2 r = 0.471, P = 0.036). Cerebral perfusion decreased during simulated SVT and VT and is influenced by age and LVEF. Clinicians can consider NIRS monitoring in patients during ablation procedures and in critical care. NIRS may especially be appropriate for the elderly and for patients with impaired LVEF.

Robotic assisted prostatic surgery in the Trendelenburg position does not impair cerebral oxygenation measured using two different monitors

Robotic assisted prostatic surgery is frequently used because of its reduced side-effects compared with conventional surgery. During surgery, an extreme Trendelenburg position and CO2 pneumoperitoneum are necessary, which may lead to cerebral oedema, can potentially reduce brain perfusion and therefore could impair cerebral oxygenation. Cerebral oxygen saturation can be measured non-invasively using near-infrared spectroscopy (NIRS). The hypothesis of the present study was that steep Trendelenburg positioning during robotic assisted prostatic surgery impairs cerebral oxygen saturation measured using two different NIRS monitors. Clinical observational study. Primary care university hospital, study period from March 2012 to February 2013. A total of 29 patients scheduled for robotic assisted prostatic surgery in a steep Trendelenburg position. Cerebral oxygen saturation was measured throughout anaesthesia using the INVOS sensor (a trend monitor using two infrared wavelengths) for one hemisphere and the FORE-SIGHT sensor (a monitor using four wavelengths of laser light to calculate absolute oxygen saturation) for the other hemisphere in an alternate randomisation. Changes in cerebral oxygenation of more than 5% during surgery in the Trendelenburg position. The median duration of Trendelenburg positioning was 190 (interquartile range 130 to 230) min. Cerebral oxygen saturation decreased with INVOS from 74 ± 5% at baseline to a lowest value of 70 ± 4% with a slope of -0.0129 min(-1) (P < 0.01) and with FORE-SIGHT from 72 ± 5% at baseline to a nadir of 70 ± 3% with a slope of -0.008 min(-1) (P < 0.01). Comparing INVOS with FORE-SIGHT, there was a good association, with a slope of 0.86 ± 0.04 (P < 0.01). Both monitors showed a clinically irrelevant decrease in cerebral oxygen saturation of less than 5% over 4 h in a steep Trendelenburg position combined with CO2 pneumoperitoneum in patients undergoing robotic assisted prostatic surgery. This extreme positioning seems to be acceptable with regard to cerebral oxygenation. clinicaltrials.gov Identifier: ID NCT01275898.

Cesarean delivery under spinal anesthesia is associated with decreases in cerebral oxygen saturation as assessed by NIRS: an observational study

Objectives:To investigate the effect of spinal anesthesia on cerebral rSO2 during elective cesarean delivery (CD).Methods:Thirty-four women scheduled for elective CD under spinal anesthesia were recruited. In the operating room rSO2 of the left and right frontal area and right thigh was recorded using three disposable sensors. A combination of 1.8–2.0 ml of 0.75% ropivacaine plus 10 μg of fentanyl were injected intrathecally. Systolic and diastolic blood pressure, heart rate, SpO2 as well as rSO2 of the left and right forehead areas and right thigh were recorded before, 5, 10, and 25 to 50 minutes after spinal injection, after uterine incision and placenta delivery, and analyzed with ANOVA repeated measures. The study was approved by the Aretaieio Hospital Institutional Review Board and registered with ClinicalTrials.gov (ID: NCT01669135).Results:The rSO2 left and right frontal area values decreased significantly from baseline (p = 0.0001 and p = 0.0001 respectively), with most remarkable decreases 5 and 10 minutes after spinal injection, from 65 (SD 8.7) % to 56 (SD 9.3) % and 56 (SD 9.5) % (p = 0.0001 and p = 0.0001) for the left and from 63 (SD 7.7) % to 55 (SD 9.3) % and 56 (SD 8.9) % (p = 0,0001 and p = 0.0001) for the right frontal area respectively. The rSO2 right thigh values increased significantly during the study period (p = 0.0001).Key limitations:Contribution of extracranial circulation to the rSO2, lack of PaCO2 and cardiac output measurements.Conclusions:Women undergoing CD under spinal anesthesia may present decreases in cerebral rSO2. The clinical impact of these results remains to be determined.Trial registration: ClinicalTrials.gov identifier: NCT01669135.

Foramen ovale perméable et migraine

Observational studies indicate an increased prevalence of patent foramen ovale (PFO) in migraineurs with aura and an increased prevalence of migraine and migraine with aura in patients with PFO but a recent stratified meta-analysis does not support pairwise association between PFO and migraine. There are conflicting data regarding causal relationship between these two conditions. According to recent studies, microembolization might provoke a decrease in cerebral oxygen saturation, thus triggering cortical spreading depression and, thereafter, migraine with aura attack. Release of vasoactive substances by activated platelets or atrial natriuretic factor are other pathophysiological explanations. Retrospective analyses of PFO closure suggest clinically significant improvements in migraine patterns. The MIST study is the only prospective study available with a good design but this study gave a negative response about cure of migraine with aura and revealed a high morbidity for such a benign condition. Although PFO closure sometimes appears to affect migraine patterns favorably, the very low grade of available evidence to support this association precludes definitive conclusions. To date, PFO closure in migraineurs with aura is not recommended in daily practice.

Evaluation of Autonomic Reserves in Cardiac Surgery Patients

Autonomic nervous system dysfunction is a well-recognized but rarely evaluated risk factor for patients undergoing cardiac surgery. By measuring autonomic reserves in patients scheduled for cardiac surgery, the authors aimed to identify those with autonomic dysfunction and to evaluate their risk of perioperative complications. This was a prospective, observational study. The study was conducted in a single academic center. Sixty-seven patients completed the study. Autonomic reserves were evaluated using analysis of heart rate variability (HRV) and blood pressure variability (BPV) after a Valsalva maneuver. The patients were divided into 2 groups depending on their response to the autonomic challenge, a group with autonomic reserves (AR, n = 38) and a group with negligible autonomic reserves (NAR, n = 29). The groups were compared for baseline psychologic distress, demographic and medical profiles, autonomic response to morphine premedication and the induction of anesthesia, hemodynamic instability, the occurrence of decreases in cerebral oxygen saturation, and postoperative complications. Patients in the NAR group had significantly higher psychologic distress scores (p < 0.001), a higher baseline parasympathetic tone (p = 0.003), were unable to increase parasympathetic tone with morphine premedication, had more severe hypotension at the induction of anesthesia (p < 0.001), more episodes of decreases in cerebral saturation (p = 0.0485), and a higher overall complication rate (p = 0.0388) independent of other variables studied. Patients with diminished autonomic reserves can be identified before cardiac surgery using analysis of HRV and BPV of the response to the Valsalva maneuver, and some evidence suggests that they may be at increased risk of perioperative complications.

Postoperative cognitive deficit after cardiopulmonary bypass with preserved cerebral oxygenation: a prospective observational pilot study

BackgroundNeurologic deficits after cardiac surgery are common complications. Aim of this prospective observational pilot study was to investigate the incidence of postoperative cognitive deficit (POCD) after cardiac surgery, provided that relevant decrease of cerebral oxygen saturation (cSO2) is avoided during cardiopulmonary bypass.MethodscSO2 was measured by near infrared spectroscopy in 35 patients during cardiopulmonary bypass. cSO2 was kept above 80% of baseline and above 55% during anesthesia including cardiopulmonary bypass. POCD was tested by trail making test, digit symbol substitution test, Ray's auditorial verbal learning test, digit span test and verbal fluency test the day before and 5 days after surgery. POCD was defined as a decline in test performance that exceeded - 20% from baseline in two tests or more. Correlation of POCD with lowest cSO2 and cSO2 - threshold were determined explorative.ResultsPOCD was observed in 43% of patients. Lowest cSO2 during cardiopulmonary bypass was significantly correlated with POCD (p = 0.015, r2 = 0.44, without Bonferroni correction). A threshold of 65% for cSO2 was able to predict POCD with a sensitivity of 86.7% and a specificity of 65.0% (p = 0.03, without Bonferroni correction).ConclusionsDespite a relevant decrease of cerebral oxygen saturation was avoided in our pilot study during cardiopulmonary bypass, incidence of POCD was comparable to that reported in patients without monitoring. A higher threshold for cSO2 may be needed to reduce the incidence of POCD.

The Intermittent Sequential Compression Device on the Lower Extremities Attenuates the Decrease in Regional Cerebral Oxygen Saturation During Sitting Position Under Sevoflurane Anesthesia

The sitting position has potential for serious complications such as cerebral ischemia and venous air embolism. This study investigated the effects of intermittent sequential compression device (SCD) on the changes in regional cerebral oxygen saturation (rSO2) during the sitting position. Sixty-six healthy patients undergoing shoulder arthroscopy in sitting position were randomly assigned to either control (N = 33) or SCD (N = 33) groups. Hemodynamic variables and the rSO2 were measured 5 minutes after the induction of anesthesia (Tsupine, baseline values), and 1, 3, and 5 minutes after raising the patient to a 70-degree sitting position (T1, T3, and T5). The incidence of hypotension was recorded. The incidence of hypotension was significantly higher in the control group (8/33) than that in the SCD group (1/33) (P = 0.027, odds ratio 0.170, 95% CI 0.042-0.684). The rSO2 was significantly higher in the SCD group compared with those in the control group at T3 and T5. Within the group, rSO2 decreased significantly only in the control group compared with baseline value at T1, T3, and T5. The % change in rSO2 from T0 to T1, T3, and T5 were significantly lower in the SCD group compared to those in the control group. The application of SCD to the lower extremities during sitting position under sevoflurane anesthesia was a simple and effective method to attenuate the decrease in cerebral oxygen saturation.

Microembolic Air Load During Contrast‐Transcranial Doppler: A Trigger for Migraine With Aura?

There is a well-known association between migraine with aura (MA) and right-to-left shunt (RILES) because of patent foramen ovale (PFO). The occurrence of MA attacks after microbubble (MB) injection during contrast-enhanced transcranial Doppler (ce-TCD) has been recently described. The aim of this study was to analyze the prevalence of RILES in a consecutive cohort of MA patients and to characterize the occurrence of MA attacks after diagnostic ce-TCD. A total of 159 consecutive MA patients underwent ce-TCD with air-mixed saline to disclose RILES. RILES was characterized in terms of MB amount (small-moderate or large) and occurrence at rest and/or during Valsalva maneuver (permanent or latent). RILES was revealed in 79/159 patients (∼ 50%). Permanent RILES were detected in 56/79 (71%) and latent RILES in 23/79 (29%) MA patients. The occurrence of a typical MA attack was overall observed in 12/159 patients (7.5%; 95% CI: 4-12.8%), but arose only in RILES-positive ones, immediately after ce-TCD (12/79; 15.2%; P< .001). All 12 patients had permanent RILES (12/56; 21.4%; P= .015) and MA attack was mostly observed in large RILES-positive patients, even without statistical significance (P= .118). Microembolic air load could act as a trigger of MA attack. According to recent studies and to the clinical characteristics observed in our patients, microembolization because of MB injection might provoke a decrease in cerebral oxygen saturation, thus triggering cortical spreading depression and, thereafter, MA attack. Larger and prospective studies will be necessary to confirm our data and observe a wider correlation.

Acute peripheral oxygen desaturation does not result in significant decreases in cerebral oxygen saturation

Acute peripheral oxygen desaturation does not result in significant decreases in cerebral oxygen saturation