SjvO2 Values Research Articles

Elevated jugular venous oxygen saturation after cardiac arrest

BackgroundWe performed a retrospective analysis of our earlier study on cerebral oxygenation monitoring by jugular venous oximetry (SjvO2) in patients of out-of-hospital cardiac arrest (OHCA). The study was focused on high SjvO2 values (≥75%) and their association with neurological outcomes and serum neuron-specific enolase (NSE) concentration. MethodForty OHCA patients were divided into (i) high (Group I), (ii) normal (Group II), and (iii) low (Group III) SjvO2, with the mean SjvO2 ≥ 75%, 55–74% and <55% respectively. The neurological outcome was evaluated using the Cerebral Performance Category scale (CPC) on the 90th day after cardiac arrest (post-CA). NSE concentration was determined after ICU admission and then at 24, 48, and 72 hours (h) post-CA. ResultsHigh mean SjvO2 occurred in 67% of patients, while no patients had low mean SjvO2. The unfavourable outcome was significantly more common in Group I than Group II (74% versus 23%, p < 0.01). Group I patients had significantly higher median NSE than Group II at 48 and 72 h post-CA. A positive correlation was found between SjvO2 and PaCO2. Each 1 kPa increase in CO2 led to an increase of SjvO2 by 2.2 %+/-0.66 (p < 0.01) in group I and by 5.7%+/-1.36 (p < 0.0001) in group II. There was no correlation between SjvO2 and MAP or SjvO2 and PaO2. ConclusionHigh mean SjvO2 are often associated with unfavourable outcomes and high NSE at 48 and 72 hours post-CA. Not only low but also high SjvO2 values may require therapeutic intervention.

Prophylactic measures to prevent cerebral oxygen desaturation events in elective beach-chair position shoulder surgeries: a systematic review and meta-analysis.

BackgroundProphylaxis for cerebral desaturation events (CDEs) during anesthesia in the beach chair position (BCP) for shoulder surgeries has not been evaluated. We systematically analyzed the effectiveness of various prophylactic measures used in this clinical setting.MethodsWe performed a meta-analysis (PROSPERO; no. CRD42020167285) of trials reporting CDEs and regional cerebral oxygen saturation (rSO2) and jugular venous oxygen saturation (SjvO2) values in anesthetized patients undergoing shoulder surgery in BCP. Considering the type of prophylactic measures used (pharmacological or non-pharmacological), a subgroup analysis was planned. Outcomes included (1) rSO2 and SjvO2 data with and without prophylactic measures for CDEs, recorded for different time intervals, and (2) the number of patients experiencing CDEs and hypotension. ResultsTwelve studies (786 patients) were included in the analysis. We observed lower absolute rSO2 values for early and all-time periods for vasoactive agent prophylaxis. The lowest achieved rSO2 values were also lower for vasoactive agent prophylaxis. Risk of CDEs was higher with vasoactive agent prophylaxis. Subgroup analysis identified targeted mild hypercarbia as effective in preserving cerebral oxygenation. Similarly, targeted mild hypercarbia prevented the fall in rSO2 with position change. Meta-regressions revealed statistically significant highest estimates for vasoactive agent prophylaxis in contrast to targeted mild hypercarbia. Likelihood of not developing CDEs was higher for targeted mild hypercarbia. In contrast to rSO2, most prophylactic methods reduced hypotensive episodes. ConclusionsTargeted mild hypercarbia can reduce BCP-related CDEs. Evidence does not favor prophylactic use of vasoactive agents for the prevention of cerebral desaturations irrespective of whether their use interferes with cerebral oximetry readings.

Koroner Arter Baypas Cerrahisinde Desfluranın Farklı MAK Değerlerinde Juguler Venöz Oksijen Saturasyonu Üzerine Etkileri

Objective: Desflurane is used in cardiac anesthesia because it provides hemodynamic stability and rapid recovery. In this study, the effects of using different minimal alveolar concentrations (MAC) of desflurane on jugular venous oxygen saturation (SjvO2) and hemodynamic parameters in coronary artery bypass surgery (CABG) were investigated. Methods: Sixty patients who were scheduled for CABG were divided into 3 groups after obtaining the hospital ethics committee and patient consent. Desflurane was used in these groups at 0.5, 1.0 and 1.5 MAC values, respectively. In addition to routine invasive catheterization, a retrograde jugular venous catheter was inserted. Hemodynamic data, SjvO2, other parameters and blood gas values were recorded before, during and after CPB. Results: SjvO2 values in all groups were not within the desaturation limit. Glucose, lactate, partial arterial O2 saturation (PaO2) and partial jugular venous O2 saturation (PjvO2) values remained normal. In each group, a decrease was observed in arterial and jugular venous O2 content difference O2CT (a-jv) values due to hypothermia and hemodilution at admission to CPB (p&lt;0.05). Conclusion: SjvO2 reflects the balance between cerebral blood flow and cerebral oxygen metabolic rate and the adequacy of cerebral perfusion. In previous studies; The effects of isoflurane, sevoflurane and desflurane on SjvO2 at 0.5 MAC level during CABG were investigated. The effects of the three inhalation agents on SjvO2 were similar. It was determined that cerebral autoregulation was not impaired and SjvO2 values did not decrease in 3 different MAC values of desflurane used in our study. However, it was observed that 0.5 MAC dose, which was also reflected in the hemodynamic findings, did not suppress the stress response sufficiently, and higher MAC values provided hemodynamic stability, especially in hypertensive patients. 1.5 MAC causes hypotension in some patients and vasopressor drugs may be needed. Hemodynamic stability is provided at a MAC value of 1.0.

Comparison of propofol and sevoflurane on cerebral oxygenation using juglar venous oximetery (SjVo2) in patients undergoing surgery for traumatic brain injury

Background:Traumatic brain injury (TBI) induces major insult to the normal cerebral physiology. The anesthetic agents may infrequently produce deleterious effects and further aggravate damage to the injured brain. This study was conducted to evaluate the effects of propofol and sevoflurane on cerebral oxygenation, brain relaxation, systemic hemodynamic parameters and levels of interleukin-6 (IL-6) in patients with severe TBI undergoing decompressive craniectomy.Methods:A prospective randomized comparative study was conducted on 42 patients undergoing surgery for severe TBI. Patients were randomized into two groups, Group P received propofol and Group S received sevoflurane for maintenance of anesthesia. All patients were induced with fentanyl, propofol, and vecuronium. The effect of these agents on cerebral oxygenation was assessed by jugular venous oxygen saturation (SjVO2). Hemodynamic changes and quality of intraoperative brain relaxation were also assessed. The serum levels of IL-6 were quantitated using enzyme-linked immunosorbent assay technique.Results:SjVO2 values were comparable and mean arterial pressure (MAP) was found to be significantly lower in Group P as compared to those in Group S (P < 0.05). Brain relaxation scores were comparable between the groups. The level of IL-6 decreased significantly at the end of surgery compared to baseline in patients receiving sevoflurane (P = 0.040).Conclusions:Cerebral oxygenation measured by SjVO2 was comparable when anesthesia was maintained with propofol or sevoflurane. However, significant reduction in MAP by propofol needs attention in patients with severe TBI. The decrease in IL-6 level reflects anti-inflammatory effect and probable neuroprotective potential of propofol and sevoflurane.

Effect of Combination of Ketamine and Propofol (Ketofol) on Cerebral Oxygenation in Neurosurgical Patients: A Randomized Double-Blinded Controlled Trial.

Background:The effects of ketofol (a combination of ketamine and propofol) on systemic hemodynamics and requirement of opioids/Propofol have already been studied and published. However, there is paucity in the literature on the effects of ketofol on cerebral oxygenation. This study aims to compare the effects of ketofol (ketamine + propofol [1:5]) with propofol on cerebral oxygenation using jugular venous oxygen saturation (SjVO2), in patients undergoing surgical clipping of intracranial aneurysms.Materials and Methods:A total of 40 World Federation of Neurosurgeons I and II patients were randomized into ketofol (n = 20) and propofol (n = 20) groups. Postinduction, SjVO2 catheter was inserted, and anesthesia was maintained with propofol and fentanyl in the propofol group and ketofol and fentanyl in the ketofol group. Jugular venous oxygen saturation (SjVO2) was obtained at baseline, 1 h and 2 h intraoperatively, and at 6 h after the surgery. Intraoperative hemodynamics and brain relaxation scores were also noted.Results:Entire SjVO2 values in both groups were within the normal limits. Higher SjVO2 values were observed in ketofol group compared to propofol at 1 and 2 h after starting of the drug and at 6 h after surgery (P < 0.05). In propofol group, a significant fall in SjVO2 was recorded at 2 h after beginning the drug as compared to the baseline (P = 0.001). More than 20% fall in mean arterial pressure (MAP) compared to baseline MAP was noted in 75% of patients in propofol group and 15% of patients in ketofol group (P = 0.002). In propofol group, 55% of patients required rescue drug phenylephrine to treat hypotension, whereas only 15% of patients required it in ketofol group (P = 0.02). Fentanyl requirement in ketofol group was less as compared to the propofol group (P = 0.022). Brain relaxation scores were comparable in both the study groups (P = 0.887).Conclusion:Maintenance of anesthesia with ketofol provides better cerebral oxygenation and hemodynamic stability compared to propofol in neurosurgical patients.

Background anaesthetic agents do not influence the impact of arginine vasopressin on haemodynamic states and cerebral oxygenation during shoulder surgery in the beach chair position: a prospective, single-blind study

BackgroundAdministration of arginine vasopressin (AVP) is associated with reducing jugular venous (SjvO2) and regional cerebral (rScO2) oxygen saturation under propofol-remifentanil (P/R) anaesthesia. We determined whether background anaesthetics modulate the effect of AVP on cerebral oxygenation and haemodynamics.MethodsWe randomly allocated 60 adult patients scheduled for shoulder surgery in the beach chair position (BCP) into 4 groups, to receive either an intravenous bolus of saline (groups PR-S and SN-S) or 0.05 U/kg AVP (groups PR-AVP and SN-AVP) under P/R or sevoflurane-nitrous oxide (S/N) anaesthesia (n = 15 each). Haemodynamic variables, SjvO2 and rScO2 were measured.ResultsAVP significantly increased mean arterial blood pressure (MAP) and decreased rScO2 in either anaesthetic group. AVP also decreased SjvO2 in the P/R groups but not in the S/N groups. The AVP-treated groups showed higher MAP and cerebral desaturation (>20% rScO2 decrease from baseline), along with lower HR and rScO2 in the BCP than those in the saline-treated groups. In contrast, AVP did not affect SjvO2 values or the incidence of SjvO2 < 50%. Baseline SjvO2 was lower and the magnitude of its reduction in the BCP was greater in the PR-AVP group than in the SN-AVP group, and the lowest SjvO2 values were 37 ± 6 and 57 ± 8%, respectively (P < 0.001).ConclusionsThe choice of anaesthetic regimen did not affect cerebral oxygenation or haemodynamics of AVP in the BCP. However, the negative effect of AVP on cerebral oxygenation should be considered, especially under P/R anaesthesia.Trial registrationClinicalTrials.gov identifier: NCT01687894, registered on September 18, 2012.

Jugular venous oximetry

AbstractThe measurement of saturation of venous blood as it drains out of brain by sampling it from the jugular bulb provides us with an estimate of cerebral oxygenation, cerebral blood flow and cerebral metabolic requirement. Arterio-jugular venous difference of the oxygen content (AVDO2) and jugular venous oxygen saturation (SjVO2) values per se helps clinicians in identifying the impairment of cerebral oxygenation due to various factors thereby prompting implementation of corrective measures and the prevention of secondary injury to the brain due to ischaemia. SjVO2 values are also used for prognostication of patients after traumatic brain injury and in other clinical situations. Sampling and measuring SjVO2 intermittently or continuously using fibreoptic oximetry requires the tip of the catheter to be placed in the jugular bulb, which is a relatively simple bedside procedure. In the review below we have discussed the relevant anatomy, physiology, techniques, clinical applications and pitfalls of performing jugular venous oximetry as a tool for measurement of cerebral oxygenation.

Impact of warming blood transfusion and infusion toward cerebral oxygen metabolism and cognitive recovery in the perioperative period of elderly knee replacement

ObjectiveThis study aims to observe the impact of the temperature of blood transfusion and infusion toward the perioperative cerebral oxygen metabolism and the postoperative cognitive recovery.MethodsEighty patients of knee replacement under epidural and general anesthesia were randomly divided into warming blood transfusion and infusion (WBI) group (n = 40) and control group (n = 40). The changes of nasopharyngeal temperature, middle cerebral artery blood flow, CERO2, and SjVO2 of the two groups were recorded at each time point for the assessment of the postoperative overall quality of recovery and cognitive recovery situation.ResultsThe nasopharyngeal temperatures of the two groups at different time points after transfusion were significantly lower than that at T1, and there was a significant difference between the two groups (P < 0.05). The CERO2 values of the two groups at T3 were significantly higher than at T1, while the SjVO2 values were significantly decreased (P < 0.01).ConclusionThe WBI can significantly reduce the occurrence of the perioperative hypothermia, while it has no significant effect toward cerebral oxygen metabolism, postoperative overall recovery, and recovery of cognitive function.

The Neurological Wake-up Test Does not Alter Cerebral Energy Metabolism and Oxygenation in Patients with Severe Traumatic Brain Injury

The neurological wake-up test (NWT) is used to monitor the level of consciousness in patients with traumatic brain injury (TBI). However, it requires interruption of sedation and may elicit a stress response. We evaluated the effects of the NWT using cerebral microdialysis (MD), brain tissue oxygenation (PbtiO2), jugular venous oxygen saturation (SjvO2), and/or arterial-venous difference (AVD) for glucose, lactate, and oxygen in patients with severe TBI. Seventeen intubated TBI patients (age 16-74 years) were sedated using continuous propofol infusion. All patients received intracranial pressure (ICP) and cerebral perfusion pressure (CPP) monitoring in addition to MD, PbtiO2 and/or SjvO2. Up to 10 days post-injury, ICP, CPP, PbtiO2 (51 NWTs), MD (49 NWTs), and/or SjvO2 (18 NWTs) levels during propofol sedation (baseline) and NWT were compared. MD was evaluated at a flow rate of 1.0 μL/min (28 NWTs) or the routine 0.3 μL/min rate (21 NWTs). The NWT increased ICP and CPP levels (p < 0.05). Compared to baseline, interstitial levels of glucose, lactate, pyruvate, glutamate, glycerol, and the lactate/pyruvate ratio were unaltered by the NWT. Pathological SjvO2 (<50 % or >71 %; n = 2 NWTs) and PbtiO2 (<10 mmHg; n = 3 NWTs) values were rare at baseline and did not change following NWT. Finally, the NWT did not alter the AVD of glucose, lactate, or oxygen. The NWT-induced stress response resulted in increased ICP and CPP levels although it did not negatively alter focal neurochemistry or cerebral oxygenation in TBI patients.

Changes in Cerebral Oxygenation in Patients With Pulmonary Dysfunction After Lung Resection

Lung resection would be associated with lower jugular bulb oxygen saturation (SjvO₂) values in patients with moderate to severe pulmonary dysfunction. We aimed to study the effects of lung resections on the postoperative changes in SjvO₂, incidence of SjvO₂ < 50%, pulmonary functions, cerebral blood flow equivalent (CBFE), and arterial to jugular difference in oxygen content (AjvDO₂) in the patients with pulmonary dysfunction. Fifty-three patients scheduled for lung resection were allocated on the basis of forced vital capacity (FVC %) and forced expiratory volume in 1 second (FEV(1)%) into the following: good FVC and FEV₁ (n = 14), mild (n = 14), moderate (n = 13), and severe (n = 12) pulmonary dysfunction groups. After lung resections, patients with pulmonary dysfunctions had significantly lower SjvO₂, CBFE, FEV₁, and FVC (P < .001), higher AjvDO₂ (P < .001), and frequent episodes with SjvO₂ < 50% (P < .03). Perioperative changes in FEV₁ had a significant negative correlation with SjvO₂ desaturation (P < .002). Patients with pulmonary dysfunction showed significant SjvO₂ < 50% after lung resection, which is correlated to the perioperative changes in FEV₁.

Arterial lactate above 2 mM is associated with increased brain lactate and decreased brain glucose in patients with severe traumatic brain injury.

Lactate fuels cerebral energy-consuming processes and it is neuroprotective. The impact of arterial lactate on brain metabolism determined by microdialysis was investigated retrospectively in patients with severe traumatic brain injury (TBI). Cerebral microdialysis (glucose, lactate), neuromonitoring (ICP, CPP, ptiO2, SjvO2) and blood gas data collected in 20 patients during pharmacologic coma were grouped within predefined arterial lactate clusters (<1, 1-2, >2 mM). Microdialysis samples were only taken from time points characterized by normoventilation (paCO2 34.5-42 mmHg), sufficient oxygenation (paO2 >75 mmHg) and hematocrit (≥24%) to exclude confounding influences. Elevated arterial lactate ≥2 mM was associated with significantly increased brain lactate which coincided with markedly decreased brain glucose despite significantly increased arterial glucose levels and sufficient cerebral perfusion indirectly determined by normal SjvO2 and ptiO2 values. At elevated arterial lactate levels signs of significantly increased cerebral lactate uptake coincided with markedly decreased cerebral glucose uptake. Infused lactate above 50 mM per 24 hours was associated with significantly decreased cerebral glucose. Increased arterial lactate levels were associated with increased cerebral lactate uptake and elevated brain lactate. At the same time brain glucose uptake and brain glucose were significantly reduced. It remains unclear whether arterial lactate is the driving force for the increased cerebral lactate levels or if the reduced glucose uptake also contributed to the increased cerebral lactate levels. Further studies are required to assess the impact of lactate infusion under clinical conditions.

Comparison between Regional Cerebral Oxygen Saturation and Jugular Bulb Venous Oxygen Saturation in Patients Undergoing OPCAB Surgery

Background: Hypoperfusion during manipulation of the heart in off-pump coronary artery bypass (OPCAB) surgery may lead to postoperative neurological complications. Therefore, it will be necessary to monitor cerebral function during OPCAB surgery. In this study, we compared regional cerebral oxygenation (rSO2) by near-infrared spectroscopy (NIRS) with jugular bulb venous oxygen saturation (SjvO2) and assessed whether rSO2 measured by NIRS could be an alternative method of SjvO2 during OPCAB surgery. Methods: A total of 20 patients who underwent OPCAB surgery were studied. A fiberoptic catheter was placed in the right jugular bulb to measure SjvO2 while a cerebral oximeter based on NIRS, INVOS 5100B was used to monitor rSO2. Radial arterial and jugular bulb blood samples were drawn simultaneously from baseline every hour during operation. The values of rSO2 were compared with SjvO2 values. Results: For all data points (n = 78) for all patients combined, rSO2 values were significantly correlated with SjvO2 values (r = 0.513, P ＜ 0.0001). There were significant correlations between arterial carbon dioxide and values of SjvO2 (r = 0.393, P = 0.0002) and rSO2 (r = 0.432, P ＜ 0.0001). Conclusions: We concluded that NIRS correlates with SjvO2 in this patient population. These findings suggest that near-infrared spectroscopy may be useful in assessing cerebral oxygenation during OPCAB surgery. (Korean J Anesthesiol 2008; 54: 47～52)

Effects of use of Thiopental + Mannitol or Etomidate + Mannitol on Cerebral Ischemia During Temporary Occlusion of Middle Cerebral Artery in Intracranial Aneurysm Surgery

Temporary vessel occlusion is an effective technique used by microvascular surgeons to facilitate dissection and permanent clipping of cerebral aneurysms. Prolonged temporary occlusion carries the risk of infarction in the territory distal to the point of occlusion. The risk of infarction can be reduced by reducing the oxygen requirements of the brain and by maintaining collateral circulation by means of blood pressure control. We studied the effects in 90 patients of etomidate + mannitol or thiopental + mannitol usage during temporary clipping in aneurysm surgery on SjVO2. group 1 received thiopental + mannitol and group 2 received etomidate + mannitol for protection before temporary clipping. After normalization of blood pressure (mild hypertension, mean arterial pressure 90-110 mm Hg) a temporary clip was used. Blood samples were taken from the jugular venous bulb catheter to assess SjVO2 at intervals during the procedure. Postoperative radiologic and clinical ischemia were evaluated with a CT scan and neurologic examination. In group 1, 6 patients were given inotropic agent infusion to maintain mean arterial pressure. However, in group 2, the inotropic agent was not required. SjVO2 values increased more than 80% in 1 patient in group 1 and in 2 patients in group 2. A new radiographic stroke was observed in 2 patients in group 2. When etomidate + mannitol was used for protection before temporary clipping, cerebral infaction appeared to be permanent as a result of the prolonged occlusion time. The results of this clinical study need further investigation.

Slow rewarming improves jugular venous oxygen saturation during rewarming

There have been many studies regarding the etiology of postoperative cognitive dysfunction after coronary artery bypass graft (CABG) surgery. Although its etiology remains unresolved, one possible factor related to postoperative cognitive dysfunction is a reduced internal jugular venous oxygen hemoglobin saturation (SjvO2) during the rewarming period. The purpose of this study was to examine the effect of rewarming rates on SjvO2 during rewarming. One-hundred patients scheduled for elective CABG surgery were randomly divided into two groups; control group (0.48 +/- 0.09 degrees C, n = 50), slow rewarming group (0.24 +/- 0.09 degrees C, n = 50). After the induction of anesthesia, a fiberoptic oximetry oxygen saturation catheter was inserted into the right jugular bulb to monitor SjvO2 continuously. Hemodynamic parameters, arterial and jugular venous blood gases were measured at nine time-points. Cerebral desaturation (defined as a SjvO2 value below 50%) during rewarming was more frequent in the control group than in the slow group. Cerebral desaturation time (duration when SjvO2 was less than 50%) and the ratio of the cerebral desaturation time to the total CPB time in the control group differed significantly from those in the slow group (control group: 17 +/- 11 min, 12 +/- 4%, slow group: 10 +/- 8 min, 7 +/- 4%, respectively, P < 0.05). There was no significant difference in mini-mental state examination on the day before the operation nor at 1 month after the surgery among four values (the day before the operation: control group; 48 +/- 8, slow group; 48 +/- 7, at one month after the surgery: control group; 46 +/- 7, slow group; 45 +/- 9). A slow rewarming rate could reduce the chance of a decrease in SjvO2 during rewarming.

Increasing Mean Arterial Blood Pressure Has No Effect on Jugular Venous Oxygen Saturation in Insulin-Dependent Patients During Tepid Cardiopulmonary Bypass

Preexisting diabetes mellitus is one of the major factors related to adverse postoperative neurological disorders after cardiac surgery. In previous reports, we found that diabetic patients more often experienced cerebral desaturation than nondiabetic patients during normothermic cardiopulmonary bypass (CPB). The purpose of this study was to examine the effects of increasing mean arterial blood pressure (MAP) by the administration of phenylephrine on internal jugular venous oxygen hemoglobin saturation (Sjvo2) during tepid CPB in diabetic patients. We studied 20 diabetic patients scheduled for elective coronary artery bypass graft surgery and, as a control, 20 age-matched nondiabetic patients. After the induction of anesthesia, a fiberoptic oximetry catheter was inserted into the right jugular bulb to monitor Sjvo2. After measuring the baseline partial pressure of the arterial and jugular venous blood gases and cardiovascular hemodynamic values, MAP was increased by the repeated administration of a 10-μg bolus of phenylephrine until it reached 100% of baseline values. There was a significant difference in Sjvo2 value between the Diabetic and Control groups after the administration of phenylephrine (Diabetic group, 56% ± 6%; Control group: 60% ± 4%) (P < 0.05). There was a significant difference in the arterial-jugular oxygen content difference value between the Diabetic and Control groups after the administration of phenylephrine (diabetic group, 4.9% ± 0.6%; Control group, 4.5% ± 0.4%) (P < 0.05). We subdivided the Diabetic group into three groups (Diet Therapy group [n = 4], Glibenclamide group [n = 10], and Insulin-Dependent group [n = 6]). There was a significant difference in the mean slopes of Sjvo2 versus cerebral perfusion pressure for increasing cerebral perfusion pressure between the Insulin-Dependent group and the other groups (Dunnett test:P = 0.04). Increasing MAP had no effects on the Sjvo2 value in insulin-dependent patients during tepid CPB.

Slow Rewarming Has No Effects on the Decrease in Jugular Venous Oxygen Hemoglobin Saturation and Long-Term Cognitive Outcome in Diabetic Patients

The purpose of this study was to examine the effects of rewarming rate on internal jugular venous oxygen hemoglobin saturation (Sjvo2) during the rewarming period, and long-term cognitive outcome in diabetic patients. We studied 30 diabetic patients scheduled for elective coronary artery bypass graft surgery. As a control, 30 age-matched nondiabetic patients were identified. The diabetic patients were randomly divided into two groups: the Slow Rewarming group (n = 15) (mean rewarming speed: 0.22° ± 0.07°C/min, mean ± sd) or the Standard Rewarming group (Standard group) (n = 15) (mean rewarming speed: 0.46° ± 0.09°C/min, mean ± sd). After the induction of anesthesia, a fiberoptic oximetry catheter was inserted into the right jugular bulb to monitor Sjvo2 continuously. Hemodynamic variables and arterial and jugular venous blood gases were measured at nine time points. All patients underwent a battery of neurologic and neuropsychologic tests on the day before the operation and at 4 mo after surgery. The Sjvo2 values in the Standard group were decreased during the rewarming period compared with at the induction of anesthesia (P < 0.05). There was a significant difference in the Sjvo2 value in the Control group between standard rewarming and slow rewarming during rewarming periods (Standard Control group: 51% ± 8%, Slow Control groups: 58% ± 5%) (P < 0.05). However, there was no difference in the Sjvo2 value in diabetic patients between standard rewarming and slow rewarming during the rewarming period. The rewarming rates (odds ratio: 0.8; 95% confidence interval: 0.5–1.3;P = 0.6) had no correlation with cognitive impairment at 4 mo after the surgery. Diabetes (odds ratio: 1.6; 95% confidence interval: 0.9–2.6;P = 0.04) was a factor in relation to cognitive impairment at 4 mo after the surgery. We concluded that a slow rewarming rate had no effects on the reduction in Sjvo2 value and long-term cognitive outcome in diabetic patients.

Cerebral tissue PO2 and SjvO2 changes during moderate hyperventilation in patients with severe traumatic brain injury.

The aim of this study was to investigate the effects of moderate hyperventilation on intracranial pressure (ICP), jugular venous oxygen saturation ([SjvO2], an index of global cerebral perfusion), and brain tissue PO2 (an index of local cerebral perfusion). Ninety-four tests consisting of 20-minute periods of moderate hyperventilation (27-32 mm Hg) were performed on different days in 36 patients with severe traumatic brain injury (Glasgow Coma Scale score < or = 8). Moderate hyperventilation resulted in a significant reduction in average ICP, but in seven tests performed in five patients it was ineffective. The response of SjvO2 and brain tissue PO2 to CO2 changes was widely variable and unpredictable. After 20 minutes of moderate hyperventilation in most tests (79.8%), both SjvO2 and brain tissue PO2 values remained above the lower limits of normality (50% and 10 mm Hg, respectively). In contrast, in 15 tests performed in six patients (16.6% of the studied population) brain tissue PO2 decreased below 10 mm Hg although the corresponding SjvO2 values were greater than 50%. The reduction of brain tissue PO2 below 10 mm Hg was favored by the low prehyperventilation values (10 tests), higher CO2 reactivity, and, possibly, by lower prehyperventilation values of cerebral perfusion pressure. In five of those 15 tests, the prehyperventilation values of SjvO2 were greater than 70%, a condition of relative hyperemia. The SjvO2 decreased below 50% in four tests; the corresponding brain tissue PO2 values were less than 10 mm Hg in three of those tests, whereas in the fourth, the jugular venous O2 desaturation was not detected by brain tissue PO2. The analysis of the simultaneous relative changes (prehyperventilation - posthyperventilation) of SjvO2 and brain tissue PO2 showed that in most tests (75.5%) there was a reduction of both SjvO2 and brain tissue PO2. In two tests moderate hyperventilation resulted in an increase of both SjvO2 and brain tissue PO2. In the remaining 17 tests a redistribution of the cerebral blood flow was observed, leading to changes in SjvO2 and brain tissue PO2 in opposite directions. CCONCLUSIONS. Hyperventilation, even if moderate, can frequently result in harmful local reductions of cerebral perfusion that cannot be detected by assessing SjvO2. Therefore, hyperventilation should be used with caution and should not be considered safe. This study confirms that SjvO2 and brain tissue PO2 are two parameters that provide complementary information on brain oxygenation that is useful to reduce the risk of secondary damage. Changes in SjvO2 and brain tissue PO2 in opposite directions indicate that data obtained from brain tissue PO2 monitoring cannot be extrapolated to evaluate the global cerebral perfusion.

Time course of changes in jugular venous oxygen saturation during hypothermic or normothermic cardiopulmonary bypass in patients with diabetes mellitus

Preexisting diabetic mellitus is a risk factor determining postoperative neurological disorders. The present study assesses the effects of normothermic and hypothermic cardiopulmonary bypass (CPB) on jugular venous oxygen saturation (SjvO2)in patients with preexisting diabetic mellitus. Sixteen diabetic patients who underwent elective coronary artery bypass grafting surgery were randomly divided into two groups: Group DN (n=8, diabetic patients) underwent normothermic CPB (>35 degrees C), and group DH (n=8, diabetic patients) underwent hypothermic CPB (32 degrees C). Controls were 16 age-matched non-diabetic patients (normothemic group, CN: n=8; hypothemic group, CH: n=8). A 4.0 F fiberoptic oximetry oxygen saturation catheter was inserted into the right jugular bulb to continuously monitor SjvO2 values. Hemodynamic parameters and arterial and jugular venous blood gases were measured seven times. Cerebral desaturation, which was defined as SjvO2 values below 50%, was observed during normothermic CPB in diabetic patients (at the onset of CPB: 46+/-3%, at 20 min after onset of CPB: 49+/-3%, means+/-SD, respectively). No cerebral desaturation occurred in diabetic and control patients during hypothermic CPB. Patients with preexisting diabetes mellitus experienced cerebral desaturation during normothermic CPB.

Jugular venous bulb oxygen saturation in patients with preexisting diabetes mellitus or stroke during normothermic cardiopulmonary bypass.

The authors hypothesized that patients with cerebrovascular abnormalities or metabolic disorders may experience abnormality in cerebral circulation more frequently than patients without these risks. The current study attempted to assess jugular venous bulb oxygen saturation (SjvO2) in patients with preexisting diabetes mellitus or stroke undergoing normothermic cardiopulmonary bypass. Thirty-nine patients undergoing elective coronary artery bypass graft surgery were studied, including 19 age-matched control patients, 10 diabetic patients, and 9 patients with preexisting stroke A 4.0-French fiberoptic oximetry oxygen saturation catheter was inserted into the right jugular bulb to continuously monitor internal SjvO2. Hemodynamic parameters and arterial and jugular venous blood gases were measured at seven time points: (1) after the induction of anesthesia and before the start of surgery, (2) just after the beginning of cardiopulmonary bypass, (3) 20 min after the beginning of bypass, (4) 40 min after the beginning of bypass, (5) 60 min after the beginning of bypass, (6) just after the cessation of bypass, and (7) at the end of the operation. No significant differences were seen in mean arterial pressure, arterial carbon dioxide tension (PaCO2), or hemoglobin concentration among the three groups during the study. The SjvO2 value did not differ among the three groups after anesthesia induction and before surgery, just after the beginning of cardiopulmonary bypass, 60 min after the beginning of bypass, just after the end of bypass, or at the end of the operation. Significant differences between the control group and the diabetic and stroke groups were observed, however, at 20 min and 40 min after the beginning of bypass (at 20 min: control group 62.2 +/- 6.8%, diabetes group 48.4 +/- 5.1%, stroke group 45.9 +/- 6.3%; at 40 min: control group 62.6 +/- 5.2%, diabetes group 47.1 +/- 5.2%, stroke group 48.8 +/- 4.1% [values expressed as the mean +/- SD]; P < 0.05). Also, values in the diabetes and stroke groups were decreased at 20 min and 40 min after the beginning of bypass compared with before the start of surgery. A reduced SjvO2 value was observed more frequently in patients with preexisting diabetes mellitus or stroke during normothermic cardiopulmonary bypass. It is possible that cerebral circulation during normothermic bypass is altered in patients with risk factors for cerebrovascular disorder.

Effects of hypothermic and normothermic cardiopulmonary bypass on brain oxygenation

Background. In this study, we assessed the effects of normothermia and hypothermia during cardiopulmonary bypass (CPB) both on internal jugular venous oxygen saturation (SjvO2) and the regional cerebral oxygenation state (rSO2) estimated by near infrared spectroscopy (NIRS).Methods. Thirty patients scheduled for elective coronary artery bypass graft surgery (CABG) were randomly divided into two groups. Group 1 (n = 15) underwent surgery for normothermic (> 35°C) CPB, and group 2 (n = 15) underwent surgery for hypothermic (30°C) CPB, and alpha-stat regulation was applied. A 4.0-French fiberoptic oximetry oxygen saturation catheter was inserted into the right jugular bulb to continuously monitor the SjvO2 value. To estimate the rSO2 state, a spectrophotometer probe was attached to the mid-forehead. SjvO2 and rSO2 values were then collected simultaneously using a computer.Results. Neither the cerebral desaturation time (duration during SjvO2 value below 50%), nor the ratio of the cerebral desaturation time to the total CPB time significantly differed (normothermic group: 18 ± 6 min, 15 ± 6%; hypothermic group: 17 ± 6 min, 13 ± 6%, respectively). The rSO2 value in the normothermic group decreased during the CPB period compared with the pre-CPB period. The rSO2 value in the hypothermic group did not change throughout the perioperative period.Conclusions. These findings suggest that near infrared spectroscopy might be sensitive enough to detect subtle changes in regional cerebral oxygenation.