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The present study investigated the reliability and sensitivity of a wearable near-infrared spectroscopy (wNIRS) device in moderate and heavy exercise intensity domains. On three separate days, eleven males performed an incremental test to exhaustion, and in the following visits, four submaximal constant-load bouts (i.e., test and retest) were performed in the moderate-intensity domain (100 and 130 W) and heavy-intensity domain (160 and 190 W). The local tissue oxygen saturation index (SmO2) and pulmonary oxygen uptake (V̇O2) were measured continuously. The absolute SmO2 and V̇O2 values and the change (Δ) from the 3rd to 6th min of exercise were calculated. There was good reliability for SmO2 measurements, as indicated by the high intraclass correlation coefficient analysis (ICC ≥0.84 for all) and low coefficient of variation between the two trials (CV ≤4.1% for all). Steady-state responses were observed for SmO2 and V̇O2 from the 3rd to the 6th min in the two moderate-intensity bouts (P>0.05), whereas SmO2 decreased and V̇O2 increased from the 3rd to the 6th min in the two heavy-intensity bouts (P<0.05). Together, these findings suggested that the SmO2 measured with a wNIRS device is reliable and sensitive to track local metabolic changes provoked by slight increments in exercise intensity.
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Objective·To explore the effect of intracardiac shunts direction on preoperative cerebral tissue oxygenation in children with congenital heart disease. Methods·Sixty children aged from 4 to 24 months diagnosed with ventricular septal defect (VSD group), tetralogy of Fallot (TOF group) and indirect inguinal hernia (control group) undergoing elective surgeries were recruited, with 20 cases in each group. The NIRS cerebral oximeter was used to monitor TOI of patients. Two sensors were placed on the subject's forehead bilaterally for continuous monitoring of cerebral oximetry. Pulse oxygen saturation (SpO2), noninvasive blood pressure, heart rate were also measured and recorded. TOI and fractional tissue oxygen extraction (FTOE) were compared among the three groups and multiple linear regression analysis was used to evaluate the relationship between TOI and these parameters. Results·There was no significant difference in TOI between VSD group and control group (P>0.05). Both sides of TOI in TOF group were significantly lower than those in other two groups (P=0.000) and FTOE in TOF group were significantly higher than those in VSD group (P=0.005). Multiple linear regression analysis showed that only SpO2 was related to TOI in children with congenital heart disease (r=0.560, P=0.000). Conclusion·Different intracardiac shunts direction can affect cerebral tissue oxygenation through affecting systemic oxygen supply. Children with right-to-left shunt physiology have lower TOI and higher FTOE due to low systemic oxygenation.
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Objective To investigate the clinical significance of central venous oxygen saturation (ScvO2) monitoring in the patients after cardiac operation.Methods Fifty patients after cardiac operation were randomly selected into this study.After the patients entered ICU 2 h,ScvO2,mixed venous oxygen saturation (S(v)vO2),lactate (Lac) were detected at the same time and oxygen extraction rate (O2ER) was calculated.Fifty patients were divided into three groups according to the level of ScvO2,group A (ScvO2 ＜0.65,23 patients),group B (ScvO2 0.65-0.75,18 patients),group C (ScvO2 ＞ 0.75,9 patients).The correlation among ScvO2,S(v)vO2,O2ER were analyzed.The correlation between ScvO2 and Lac in each group were calculated.The level of Lac in three groups were compared.The incidence rate of complications,ventilator time and ICU stay time were compared.Results The level of ScvO2,S（v）O2,O2ER,Lac in 50patients were 0.656 ±0.086,0.639 ±0.081,0.356 ±0.084,(2.6 ± 1.3) mmol/L.The level of ScvO2 had significantly positive correlation with S(v)O2 (r =0.688,P ＜ 0.01),and had significantly negative correlation with O2ER (r =-0.640,P ＜0.01).In group A,the level of Lac had significantly negative correlation with ScvO2 (r =-0.772,P ＜ 0.01).In group C,the level of Lac had significantly positive correlation with ScvO2 (r =0.717,P ＜ 0.05).In group B,the level of Lac had no significant correlation with ScvO2 (r =-0.358,P ＞0.05).The level of Lac in group A and group C was significantly higher than that in group B [(2.0 ± 0.9),(4.8 ±2.1) mmol/L vs.(1.6 ±0.5) mmol/L] (P ＜0.05 or ＜0.01).The incidence rate of hyoxemia,low cardiac output syndrome and renal functional lesion in group A were significantly higher than those in group B (P ＜ 0.05).The incidence rate of liver functional lesion and renal functional lesion in group C were significantly higher than those in group B (P ＜ 0.05).The ventilator time and ICU stay time in group A andgroup C were significantly longer than those in group B (P ＜ 0.05).Conclusions ScvO2 is an ideal index to judge oxygen equilibrium in early period after cardiac operation.The lower and supranormal ScvO2 both suggest tissue hypoxia,resulting in increased postoperative complications and prolonged treatment.
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To evaluate the effect of thoracic epidural anesthesia (TEA) on tissue oxygen delivery and utilization in patients undergoing cardiac surgery. This prospective observational study was conducted in a tertiary referral heart hospital. A total of 25 patients undergoing elective off-pump coronary artery bypass surgery were enrolled in this study. All patients received thoracic epidural catheter in the most prominent inter-vertebral space between C7 and T3 on the day before operation. On the day of surgery, an arterial catheter and Swan Ganz catheter (capable of measuring cardiac index) was inserted. After administering full dose of local anesthetic in the epidural space, serial hemodynamic and oxygen transport parameters were measured for 30 minute prior to administration of general anesthesia, with which the study was culminated. A significant decrease in oxygen delivery index with insignificant changes in oxygen extraction and consumption indices was observed. We conclude that TEA does not affect tissue oxygenation despite a decrease in arterial pressures and cardiac output.
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Aged , Anesthesia, Epidural , Coronary Artery Bypass, Off-Pump , Female , Hemodynamics , Humans , Male , Middle Aged , Oxygen/metabolism , Oxygen Consumption , Prospective StudiesABSTRACT
Objective To observe the change of cerebral oxygen metablism and the level of blood lactate in early stage of sepsis in rats.Method Sixty-four SD rats were randomly(random number)divided into septic group and control group.The sepsis model of rat was made by lipopolysaccharide (LPS,10 mg/kg)injected intra-abdominally,and rats of control group were treated with the same amount of physiological saline instead.And each group was further divided into 4 sub-groups of4 h,6 h,12 h and 24 h after treatment.At each interval,blood samples were obtained via jugular vein for detecting blood oxygen saturation (Sjv02)and blood lactate(LA).The blood oxygen saturation(Sa02)of ventral aorta was also measured.Arteriovenous oxygen content difference (AVD02) and oxygen extraction fraction (OEF) were studied.These four variables were analyzed and compared between two groups.Results The AVD02 and OEF in sepsis group were higher than those in control groups of 3 h,6 h and 12 h (P0.05).LA in sepsis group was higher than that in control group in each interval (P<0.05).Conclusions In early stage of sepsis,cerebral perfusion,cerebral oxygen supply and cerebral oxygen extraction increase.The global oxygen metabolic variables(Sjv02,AVD02 and OEF)and the level of LA can be used to objectively and accurately evaluate the cerebral oxygen metabolic dysfunction in early stage of sepsis.
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@#BACKGROUND: High-volume hemofiltration (HVHF) is technically possible in severe acute pancreatitis (SAP) patients complicated with multiple organ dysfunction syndrome (MODS). Continuous HVHF is expected to become a beneficial adjunct therapy for SAP complicated with MODS. In this study, we aimed to explore the effects of fluid resuscitation and HVHF on alveolar-arterial oxygen exchange, the Acute Physiology and Chronic Health Evaluation II (APACHE II) score in patients with refractory septic shock. METHODS: A total of 89 refractory septic shock patients, who were admitted to ICU, the Provincial Hospital affiliated to Shandong University from August 2006 to December 2009, were enrolled in this retrospective study. The patients were randomly divided into two groups: fluid resuscitation (group A, n=41), and fluid resuscitation plus high-volume hemofiltration (group B, n=48). The levels of O2 content of central venous blood (CcvO2), arterial oxygen content (CaO2), alveolar-arterial oxygen pressure difference P(A-a)DO2, ratio of arterial oxygen pressure/alveolar oxygen pressure (PaO2/PAO2), respiratory index (RI) and oxygenation index (OI) were determined. The oxygen exchange levels of the two groups were examined based on the arterial blood gas analysis at different times (0, 24, 72 hours and 7 days of treatment) in the two groups. The APACHE II score was calculated before and after 7-day treatment in the two groups. RESULTS: The levels of CcvO2, CaO2 on day 7 in group A were significantly lower than those in group B (CcvO2: 0.60±0.24 vs. 0.72±0.28, P<0.05; CaO2: 0.84±0.43 vs. 0.94±0.46, P<0.05). The level of oxygen extraction rate (O2ER) in group A on the 7th day was significantly higher than that in group B ( 28.7±2.4 vs. 21.7±3.4, P<0.01). The levels of P(A-a)DO2 and RI in group B on the 7th day were significantly lower than those in group A. The levels of PaO2/PAO2 and OI in group B on 7th day were significantly higher than those in group A (P<0.05 or P<0.01). The APACHE II score in the two groups reduced gradually after 7-day treatment, and the APACHE II score on the 7th day in group B was significantly lower than that in group A (8.2±3.8 vs. 17.2±6.8, P<0.01). CONCLUSION: HVHF combined with fluid resuscitation can improve alveolar- arterial-oxygen exchange, decrease the APACHE II score in patients with refractory septic shock, and thus it increases the survival rate of patients.
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Objective To evaluate the effects of fluid resuscitation and large-volume hemofiltration (HVHF) on the Alveolar-arterial oxygen exchange in patients with refractory septic shock. Method A total of 89 intensive care patients with refractory septic shock treated with fluid resuscitation and/or HVHF were enrolled between August 2006 and December 2009. All the patients were randomly divided into two groups. In group A, patients were treated with fluid resuscitation, n = 41 cases) and in group B, patients were treated with large-volume hemofiltration and fluid resuscitation, n =48). The O2 content of central venous blood(CcvO2), arterial oxygen content (CaO2), Alveolar-arterial oxygen pressure difference (P(A-a)DO2), the ratio of arterial oxygen pressure/alveolar oxygen pressure (PaO2/PAO2), respiratory index (RI) and oxygenation index (OI) were checked. The levels of oxygen exchange in two groups were detected by arterial blood gas analysis before treatnent, 24 hour, 72 hour and 7 days after treatment. The APACHE Ⅱ scores in patients with refractory septic shock were measured before and the 7th day after treatment with HVHF and/or fluid resuscitation respectively. Data were analyzed by using t -test and chi-square test to compare the differences and ratio between two groups and were expressed in mean ± standard deviation, and the analysis of variance was done with SPSS version 12.0 software. Results ① The differences in CcvO2 and CaO2 between two groups were[(0.60±0.24) vs. (0.72±-0.28), P ＜0.05 and (0.84±0.43) vs. (0.94±0.46), P ＜0.05]; and the oxygen extraction rates (O2ER) were significantly different between two groups [(28.7±2.4) vs. (21.7±3.4), P<0.01];② The levels of P(A-a)DO2、ratio of PaO2/PAO2、RI and OI in group B were reduced more significantly than in group A (P<0.05 or P<0.01);③The APACHE Ⅱ scores in both groups were gradually reduced after treatment for 7 days, and the APACHE Ⅱscore in group B on the 7th day of treatment were lower than that in group A[(17.2 ± 6.8) vs. (8.2 ± 3.8), P ＜ 0.01]. Conclusions Fluid resuscitation and HVHF could improve alveolar-arterial-oxygen exchange in patients with refractory septic shock, and at the same time decreased the APACHE Ⅱ scores, improving the survival rate of patients.
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BACKGROUND: During intracranial brain surgery, numerous factors may alter cerebral blood flow and the oxygen supply-demend balance. Continuous monitoring of the jugular bulb venous oxygen saturation (SjvO2) may help in the anesthetic management of such procedures. METHODS: Fiberoptic SjvO2 was continuously monitored and recorded 1, 3 and 5 min after the skin incision, skull bone craniotomy, dura open and dura closure in 20 patients. RESULTS: The SjvO2 was increased after the skin (scalp) incision at 1, 3 and 5 minutes and also after endotracheal suctioning for removal of secretions. CONCLUSIONS: Although the accuracy of Fibroptic SjvO2 determination is limited, it allows the detection of cerebral blood flow and oxygen supply-demend imbalance during brain surgery. The frequent occurance of SjvO2 elevations is suggestive of reactive hyperemia mechaniams.
Subject(s)
Humans , Brain , Craniotomy , Hyperemia , Ischemia , Oxygen , Skin , Skull , SuctionABSTRACT
BACKGROUND: The cerebral vascular response to CO2 has been reported to be preserved during isoflurane and propofol anesthesia. This study compared the cerebral oxygen extraction ratio during normoventilation versus hyperventilation in propofol anesthesia and isoflurane anesthesia. METHODS: 28 patients undergoing cerebral aneurysmal surgery were studied following informed consent. In the isoflurane group (n = 14), anesthesia was induced with thiopental 5 mg/kg, and maintained with isoflurane and nitrous oxide (N2O) in oxygen (FiO2 0.33). In the propofol group (n = 14), anesthesia was induced with propofol 2 mg/kg, and maintained by infusion of propofol and N2O-O2 (FiO2 0.33). Monitoring included measurement of mean arterial blood pressure, heart rate, body temperature, end-tidal CO2 (PetCO2), jugular bulb O2 saturation (SjO2) and arterial O2 saturation (SaO2). Mechanical ventilation was adjusted to achieve PetCO2 levels of 40 and 25 mmHg. Ten minutes of equilibration were allowed at each PetCO2 level. Blood was sampled from the jugular bulb and radial artery at each PetCO2 level (40 and 25 mmHg). The cerebral oxygen extraction ratio was calculated as (CaO2 CjO2) / CaO2 (CaO2; arterial oxygen content, CjO2; jugular bulb oxygen content). RESULTS: The cerebral oxygen extraction ratio was higher in hyperventilation (PetCO2 25 mmHg) compared to normoventilation (PetCO2 40 mmHg) in each group (P < 0.05) and higher in the propofol group compared to the isoflurane group (P < 0.05). CONCLUSIONS: The increased cerebral oxygen extraction ratio in hyperventilation during both isoflurane and propofol anesthesia showed that cerebral vascular CO2 reactivity was maintained during both isoflurane anesthesia and propofol anesthesia. The cerebral oxygen extraction ratio was higher during propofol anesthesia compared to isoflurane anesthesia in both normoventilation and hyperventilation, therefore this data showed that cerebral blood flow was lower during propofol anesthesia compared to isoflurane anesthesia.
Subject(s)
Humans , Anesthesia , Arterial Pressure , Body Temperature , Heart Rate , Hyperventilation , Informed Consent , Intracranial Aneurysm , Isoflurane , Nitrous Oxide , Oxygen , Propofol , Radial Artery , Respiration, Artificial , ThiopentalABSTRACT
In order to learn the tissuse perfusion and oxygenization in the patient with septic shock (SS) in Qinghai plateau,25 cases having suffered from SS in Xining,the capital of Qinghai province, were divided into death group (group D) and survival group(group S), and the data of oxygen dynamics, determined by Swan-Ganz cathter and thermodilution methods,were analyzed retrospectively. The results showed that the oxygen delivery (DO_2) and oxygen consumption (VO_2) increased to varying degrees in all of cases;VO_2 was positively correlated with DO_2, and in group D the correlation remained significant during whole duration of disease,but in group S it became unsignificant as DO_2 was above 700 ml?min~(-1)?m~(-2); the oxygen extraction rate decreased markedly in both groups,but much more in group D. These suggest that the insufficient oxygenization of general tissuse in patient with SS results from the dysfunction of oxygen extraction,and increasing DO_2 is helpful for the shock resuscitation except VO_2 is persistently and positively correlatded with DO_2.
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Thoracic epidural combined with general anesthesia is used for thoracic and upper abdominal surgery and postoperative pain control. This technique has advantages of reducing the hemodynamic demand on the heart because of cardiac sympathetic block and stable intraoperative hemodynamics, but it may have a potential hazard of reducing coronary perfusion pressure due to hypotension. Decreased coronary perfusion pressure may be critical hazard to coronary insufficiency patients, but coronary vascular resistance may be decreased also due to blockade of sympathetic coronary constriction. This study was done to investigate the effect of thoracic epidural anesthesia on myocardial and systemic circulation during coronary occlusion limiting flow to 50% of preocclusive value. Comnary occlusion of left circumflex coronary artery was achieved with hydraulic vascular occluder with blood flow meter distal to occluder in 20 dogs. Five of them were dead during preparation. Coronary stenosis was maintained for 30 minutes, then epidural anesthesia was done with 0.5% bupivacaine (bupiva group) or saline (saline group) 5 ml through the surgically introduced epidural catheter. Arterial, mixed venous and coronary sinus blood was collected for the measurement of metabolites and myocardial and systemic oxygen comsumption and extraction ratio. Hemodynamic parameters and blood samples were obtained before(control), 30 minutes after stenosis(stenosis), 15, 30, 60, 90 and 120 minutes after epidural blockade. The results were as follows; The thoracic epidural block caused decrease in blood pressure, heart rate, cardiac index, level of free fatty acid and glucose, and increase in lactic acid level of mixed veous and coronary sinus blood, myocardial oxygen extraction ratio, arterio-venous oxygen content difference, and systemic oxygen extraction ratio. In conclusion the high thoracic epidural block may cause hypotension thus decrease oxygen supply to myocardium but the degree of which is less than that of total body, in the dogs with acute coronary stenosis. The reason is that the high thoracic epidural block decrease myocardial oxygen consumption, and make effective distribution of blood flow in ischemic myocardium, but the normal myocardium has the highest oxygen extraction in the body, so the high thoracic epidural block in coronary stenosis may cause ill effect on myocardial oxygen equlibrium.