Retrograde cerebral perfusion versus selective cerebral perfusion as evaluated by cerebral oxygen saturation during aortic arch reconstruction.

BACKGROUND: Time limits for neuroprotection by retrograde cerebral perfusion (RCP) and selective cerebral perfusion (SCP) in aortic arch aneurysm repair or dissection are undergoing definition. METHODS: Using near-infrared optical spectroscopy, changes in regional cerebrovascular oxygen saturation (rSO2) were compared between the two perfusion methods. RESULTS: Immediately before cardiopulmonary bypass, baseline rSO2 was 63.9%+/-6.9% for the RCP and 66.1%+/-5.3% for the SCP group (no significant difference). As patients were core-cooled to 20 degrees C, rSO2 increased to 73.1%+/-8.8% and 74.1%+/-7.9% in the RCP and SCP groups, respectively. With circulatory arrest, rSO2 suddenly decreased. After starting cerebral perfusion, rSO2 returned to prearrest values in the SCP group but continued decreasing steadily in the RCP group, to levels below baseline after about 25 minutes. At the end of perfusion, rSO2 was 57.4%+/-12.2% for the RCP group and 71.7%+/-6.9% for the SCP group, and the ratio of rSO2 to baseline value was 0.89 for RCP and 1.08 for SCP despite a shorter brain perfusion time for RCP (38.8+/-18.0 versus 103.3+/-43.3 minutes). Three of 5 patients whose ratios of rSO2 to baseline at the end of brain protection were 0.7 or less had neurologic deficits. CONCLUSIONS: Although SCP showed no clinically important time limitation, rSO2 continued to decrease with time during RCP. An rSO2 ratio less than 0.7 could represent a critical lower limit.     

Effective cerebral protection using near-infrared spectroscopy monitoring with antegrade cerebral perfusion during aortic surgery

Abstract Objective: Antegrade cerebral perfusion (ACP) under moderate hypothermia may improve cerebral protection. Intraoperative measurement of cerebral regional oxygen saturations (rSO2) using near‐infrared spectroscopy (NIRS) can provide accurate monitoring of cerebral perfusion during ACP. We evaluated the role, outcomes, and advantages of using NIRS in providing effective cerebral protection with ACP. Methods: Between May 2006 and March 2009, 27 patients (mean age 60%, 93% elective) underwent ascending aorta replacement with ACP monitored by NIRS. ACP was established through the right axillary artery (n = 26). All patients had continuous intraoperative measurement of both anterior cerebral rSO2 using NIRS (INVOS; Somanetics Corporation, Troy, MI, USA). Posterior cerebral perfusion was measured using left radial artery pressures. Quality of life (QoL) was assessed using a Short Form 36 questionnaire. Results: Mean cardiopulmonary bypass and aortic cross clamp time were 169 ± 27 and 95 ± 22 minutes, respectively. Mean ACP rate of 1.27 ± 0.35 L/min provided a mean left radial artery pressure of at least 60 mmHg. All patients’ cerebral rSO2 were maintained above their baseline using NIRS. Mean ACP time was 14.3 ± 2.6 minutes at a mean core temperature of 23.4 °C ± 2.0 °C. Temporary neurological deficit was observed in two patients (7.4%). No permanent neurological dysfunction was observed. Thirty‐day mortality was 3.7%. At median follow‐up of 18.3 (interquartile range 10.8 to 23.3) months survival was 92% and mean norm‐based QoL score was above average at 52.5 ± 6.5. Conclusion: Cerebral rSO2 and left radial artery pressure monitoring with ACP during aortic surgery provides accurate measurement of cerebral perfusion resulting in minimal neurological and perioperative complications and good midterm QoL outcomes.     

Total arch replacement using antegrade selective cerebral perfusion with right axillary artery perfusion.

OBJECTIVE: Right axillary artery (AxA) perfusion, which can prevent cerebral embolism caused by retrograde perfusion via the femoral artery (FA), was used for selective cerebral perfusion (SCP) as well as cardiopulmonary bypass (CPB) in aortic arch repair. We review the outcome of aortic arch surgery using SCP with right AxA perfusion to clarify its efficacy. METHOD: Between 1998 and 2002, 120 patients underwent aortic arch repair using SCP with right AxA perfusion. The mean age was 69+/-10 years. Aneurysms were atherosclerotic in 79, dissecting in 32, and others in nine patients. Twenty of them (16.7%) required emergency surgery. CPB was initiated with right AxA and FA perfusion, and following SCP was established using right AxA and left common carotid artery perfusion. RESULTS: With right AxA perfusion, hospital mortality was 5.8%. Multivariate analysis showed only ruptured aneurysm was an independent determinant for hospital mortality. Permanent neurological dysfunction developed in one patient (0.8%), while seven (5.8%) suffered from temporary one. In univariate analysis, SCP time, stenosis of the carotid arteries, past history of cerebrovascular events, and atherosclerotic aneurysm were not related to temporary neurological deficits CONCLUSION: Right AxA perfusion in conjunction with SCP is a safe and useful alternative for brain protection in total arch replacement.     

Comparative clinical study between retrograde cerebral perfusion and selective cerebral perfusion in surgery for acute type A aortic dissection.

OBJECTIVE: Selection of a brain protection method is a primary concern for aortic arch surgery. We performed a retrospective study to compare the respective advantages and disadvantages of retrograde cerebral perfusion (RCP) and selective cerebral perfusion (SCP) in patients who underwent surgery for acute type A aortic dissection. METHODS: The study reviewed 166 patients who underwent surgery at Nagoya University or its eight branch hospitals between January 1990 and August 1996. There were 91 patients who received SCP and 75 patients who underwent RCP. Results for these two groups were compared. RESULTS: There were no significant differences in age, gender, Marfan syndrome rate, DeBakey classification, or emergency operation rate. Rates of various preoperative complications were similar except for aortic valve regurgitation. Arch replacement was performed more often in SCP than in RCP patients (49% vs. 27%, P = 0.0028). There were no significant differences between groups in cardiac ischemic time or visceral organ ischemic time. However, RCP group showed shorter cardio-pulmonary bypass time (297+/-99 vs. 269+/-112 min, P = 0.013) and lower the lowest core temperature (21.6+/-3.1 degrees C vs. 18.7+/-2.1 degrees C, P = 0.0001). SCP duration was longer than RCP duration (103+/-56 vs. 54+/-24 min, P < 0.0001). Despite these differences, RCP patients were not significantly different from SCP patients with regard to any postoperative complication, neurological dysfunction (16 vs. 19%), or operative mortality (all deaths within the hospitalization; 24 vs. 21%). Regarding neurologic dysfunction, there were six cases of coma, six of motor paralysis, two of paraplegia and one of visual loss among SCP patients, and eight cases of coma, three of motor paralysis, and three of convulsion in the RCP group. The incidence of motor paralysis was higher in the SCP group, while the incidence of coma was higher in the RCP group. CONCLUSIONS: RCP can be performed without clamping or cannulation of the cervical arteries, which is an advantage in reducing the chances of arterial injury or cerebral embolization. RCP is comparable to SCP in terms of clinical outcome.     

Clinical implication of orbital ultrasound monitoring during selective cerebral perfusion

BACKGROUND: We evaluated clinical relevance of orbital ultrasound (OUS) monitoring to neurological events in aortic surgery associated with selective cerebral perfusion (SCP). METHODS: In 24 consecutive cases, blood flow was monitored at central retinal artery (CRA) and retrobulbar vessels. The threshold perfusion pressure for detecting CRA flow in the color Doppler mode (BPt) was determined in individual eyes. RESULTS: The BPt ranged from 25 to 71 mm Hg. Events (infarction, anisocoria, delirium) occurred in 8 cases. Infarction occurred in all 3 cases when retrobulbar flow was severely impaired for 40 minutes or longer, while none of the remaining 21 cases had infarction (p = 0.0005). Among the latter cases, perfusion pressure was below BPt for longer than 100 minutes in all 5 cases with events, and in 5 of 16 cases without events (p = 0.0124). No significant difference was found in age, duration of cardiopulmonary bypass, SCP, and circulatory arrest, and duration of blood pressure below 50 mm Hg. CONCLUSIONS: Sustained hypoperfusion detected with OUS monitoring is related to an occurrence of neurological events.     

A cardiopulmonary bypass perfusion technique for the surgical repair of aortic type I dissections requiring the elephant trunk procedure

The effect of cerebral and spinal cord protection by a modified perfusion technique during the elephant trunk procedure was assessed. Between 1997 and 1998, six patients underwent selective cerebral perfusion (SCP) and lower half of the body perfusion (LBP), in which the right subclavian and left femoral arteries were separately cannulated and perfused by individual pump heads. Moderate systemic cooling was used (nasal temp. 20-30 degrees C; rectal temp. 23-26 degrees C). The open distal aortic repair was performed using only the selective cerebral perfusion; while the aortic arch reconstruction was performed using both selective cerebral and lower half of the body simultaneous perfusion. Blood oxygen saturation of the left jugular vein (SjO2) and regional oxygen saturation cerebral (rSO2) in the front region of the brain, was monitored along with the pressure of the left temporal superficial and femoral artery. The mean cardiopulmonary bypass time was 136 minutes, with a mean arrest time of 92 minutes. Mean duration of isolated selective cerebral perfusion was 23 minutes, with flow rates of 5-8 mL/kg/min; a left temporal superficial artery pressure of 50 mmHg; SjO2 65-80%, and rSO2 58-72%. Mean duration of simultaneous selective cerebral and lower half of the body perfusion was 27 minutes; cerebral flow rates 5-8 mL/kg/min; the left temporal superficial artery pressure of 45-50 mmHg; SjO2 70-85% and rSO2 55-76%. At the same time, lower half of the body flow rates were maintained within 30-50 mL/kg/min; with a femoral artery pressure 50-80 mmHg. Mean extubation time was 28 hours; mean ICU time was 4.5 days. There were no neurologic complications in any patient. All patients survived the operation and were discharged from the hospital. This modified perfusion technique of SCP and LBP worked well and provided satisfactory cerebral and spinal cord protection.     

Impact of organ malperfusion on mortality and morbidity in acute type A aortic dissections

BACKGROUND: Organ malperfusion is a serious complication of acute type A aortic dissection. Management and outcome of malperfusion has been discussed in this study. METHODS: Between November 1994 and May 2003, 118 patients with acute type A aortic dissections were operated. Fifty-seven patients (48.3%) were complicated with organ malperfusion, which is considered as group I. Seventy-three ischemic events were seen in 57 patients with organ malperfusion. Patients in group I were divided into four subgroups according to affected organ system including limb (38 events), coronary (9 events), renal (2 events), visceral (9 events), and cerebral (15 events) ischemia. Sixty-one patients without organ malperfusion constitute group II. RESULTS: The hospital mortality rate was 42.1% (24 of 57) in patients with malperfusion, 14.75% (9 of 61) in group II (p = 0.001), and 27.9% (33 of 118) in all patients. Postoperative complications such as mediastinal hemorrhage, low cardiac output, gastrointestinal system complications, acute renal failure, and multiple organ failure were higher in group I. Mesenteric and limb ischemia associated with high mortality. Multivariate analysis reveals that visceral malperfusion is the strongest predictor of postoperative mortality (odds ratio: 25.09, p = 0.000). Isolated coronary malperfusion had the lowest mortality (one patient, 16.6%) among the patients with organ malperfusion. CONCLUSIONS: Acute type A aortic dissections with organ malperfusion has higher postoperative mortality and morbidity. Immediate aortic repair is our management strategy in patients with limb, coronary, and neurological malperfusion. To reduce the extremely high mortality with mesenteric malperfusion, new strategies should be investigated such as surgical delay with interventional procedures.     

A retrospective study of changes in cerebral oxygenation using a cerebral oximeter in older patients undergoing prolonged major abdominal surgery

BACKGROUND AND OBJECTIVE: The objective was to carry out a retrospective study of changes in regional cerebral oxygen saturation (rSO2) using the Somanetics Invos Cerebral Oximeter (SICO) in older patients undergoing prolonged major abdominal surgery. Since evidence is accumulating that detection and correction of falls in rSO2 may be associated with a reduced incidence of postoperative cognitive dysfunction, the study assessed the incidence and possible predisposing factors for significant falls in rSO2 and strategies for correction. METHODS: Data from 46 consecutive patients aged 55 yr or above undergoing major abdominal surgery were collected and studied. A SICO electrode was placed over the right forehead prior to commencement of anaesthesia and values of rSO2 were recorded automatically on a floppy disk at 20 s intervals throughout the procedure and until transfer of the patient to the postanaesthesia care unit. Anaesthesia and physiological data were routinely collected by the author on an anaesthetic record computer and transferred to an Excel spreadsheet for analysis. RESULTS: Average duration of the surgery exceeded 7 h. Average blood loss was 1363 mL (interquartile range 500-2000). In 11 of the 46 patients the rSO2 drop exceeded 20%, and in six, there was a significant temporal association of rSO2 drop with ongoing major haemorrhage. In 23 of the 46 patients, a maximum drop in rSO2 occurred, which was about 15% or more. Fall in rSO2 in the 46 patients significantly correlated with blood loss (P < 0.05) and percentage fall in haemoglobin (Hb) (P = 0.01) but not with lowest Hb. Despite maintenance of conventional haemodynamic parameters such as systolic blood pressure (BP) in most patients, the fall in rSO2 seemed only reversible by blood transfusion. In five of the six patients who experienced the greatest decline in rSO2 during haemorrhage, there was no correlation between fall in rSO2 and systolic BP. CONCLUSIONS: This retrospective study confirms that a significant reduction in rSO2 is a common accompaniment to prolonged major abdominal surgery in elderly patients, especially if associated with blood loss, and is correctable by blood transfusion. In most cases, these changes would have gone unnoticed with conventional monitoring.     

An evaluation of bilateral monitoring of cerebral oxygen saturation during pediatric cardiac surgery

Cerebral oximetry is a technique that enables monitoring of regional cerebral oxygenation during cardiac surgery. In this study, we evaluated differences in bi-hemispheric measurement of cerebral oxygen saturation using near-infrared spectroscopy in 62 infants undergoing biventricular repair without aortic arch reconstruction. Left and right regional cerebral oxygen saturation index (rSO2i) were recorded continuously after the induction of anesthesia, and data were analyzed at 12 time points. Baseline rSO2i measurements were left 65 +/- 13 and right 66 +/- 13 (P = 0.17). Mean left and right rSO2i measurements were similar (< or =2 percentage points/absolute scale units) before, during, and after cardiopulmonary bypass, irrespective of the use of deep hypothermic circulatory arrest. Further longitudinal neurological outcome studies are required to determine whether uni- or bi-hemispheric monitoring is required in this patient population.     

Bilateral monitoring of cerebral oxygen saturation results in recognition of aortic cannula malposition during pediatric congenital heart surgery

Congenital heart surgery is associated with a 2-25% reported incidence of neurological complication. Near-infrared spectroscopy (NIRS) can detect changes in regional cerebral saturation index (rSO2i) during cardiac surgery. If rSO2i decreases significantly, treatment algorithms are used to restore baseline values, potentially avoiding neurological complications. The efficacy of bilateral NIRS monitoring in pediatric congenital heart surgery has been debated. We report a case in which bilateral NIRS monitoring detected an abrupt decrease in rSO2i (right greater than left) after initiation of bypass without abnormalities detected by standard monitors. This resulted in prompt surgical intervention that restored rSO2i, potentially preventing neurological injury.     

Predictor of neurologic dysfunction after elective thoracic aorta repair using selective cerebral perfusion

OBJECTIVES: This study was undertaken to determine the factors that influence postoperative neurological dysfunction after selective cerebral perfusion (SCP). DESIGN: From 1995 to August 2004, 60 patients were evaluated for the presence of cerebro-vascular disease (CVD), and then underwent thoracic aortic operations using SCP. Perioperative factors were evaluated by multivariate analyses. RESULTS: Hospital mortality rate was zero. Sixteen patients (26.7%) proved to have CVD. Permanent neurological dysfunction (PND) appeared in three patients (5.0%) and transient neurological dysfunction (TND) in two (3.3%). Univariate analysis revealed superficial temporal artery (STA) pressure during SCP (p = 0.0410) to be a significant risk factor for PND. Variables that achieved values of p < 0.2 (aortic cross-clamp time, presence of CVD, old cerebral infarction, presence of clots or atheroma) were examined with multivariate analysis and the presence of CVD (p = 0.038) and STA pressure during SCP (p = 0.032) were independent risk factors for PND. Multivariate analysis for TND did not show any risk factor. CONCLUSIONS: The presence of CVD was indicated as an independent risk factor for PND after thoracic aortic operations using SCP.     

Arch and descending aortic aneurysms: influence of perfusion technique on neurological outcome.

OBJECTIVE: Although cannulation of the femoral artery is used routinely for thoracic aortic operations with hypothermic circulatory arrest, retrograde perfusion through the descending aorta carries the risk of cerebral malperfusion or embolism. We have, therefore, routinely used a central cannulation technique for distal arch and descending aortic operations since 1995. In this study, we compared neurological outcome in consecutive patients undergoing femoral versus ascending aortic perfusion for these aneurysms. METHODS: Between 1987 and 1998, 61 patients underwent aortic resection with circulatory arrest, but without retrograde cerebral perfusion, for lesions of the aortic arch and descending aorta. Thirty-one patients had fusiform true aneurysms, 19 had aortic dissection and 11 had extensive saccular or false aneurysms. Thirty-two patients (52%) were perfused via the femoral artery (group A), and 29 patients (48%) from the ascending aorta (group B). Operative mortality and morbidity, and neurological outcome, were reviewed. RESULTS: There were no differences between the groups in mean age, pathology, abdominal and peripheral vascular disease, net perfusion time, or circulatory arrest time. There were four hospital deaths (three in group A and one in group B; P = 0.61), including one neurological death in group A, group A suffered a higher incidence of neurological events (nine patients: 28%) than group B (two patients: 7%; P = 0.03). Temporary focal neurological deficits occurred in both groups (two patients in group A, 6% and two patients in group B, 7%; P > 0.99), but permanent injury occurred exclusively in group A (seven patients: four with monoplegia, one with hemiplegia, and two with diffuse cerebral injury with one death; P = 0.01). CONCLUSIONS: Anterograde perfusion using a proximal aortic cannula provides a low risk of cerebral embolism and allows extensive aortic resection with low morbidity.     

局部脑氧饱和度监测在老年患者术中应用的研究进展

背景 局部脑氧饱和度(regional cerebral oxygen saturation,rSO2)监测是一种新型无创监测脑氧平衡的方法,老年患者术中实时监测rSO2可以优化老年患者围手术期的管理,降低术后神经系统并发症的发生. 目的 为rSO2监测的相关研究和临床应用提供参考. 内容 主要介绍rSO2的基本原理、影响因素及rSO2在老年患者心脏手术、神经外科手术、胸外科、腹外科及骨科中的应用. 趋向 积极探索rSO2在老年患者中的应用价值,减少老年患者术后并发症.     

Monitoring cerebral oxygen saturation in elderly patients undergoing general abdominal surgery: a prospective cohort study

BACKGROUND AND OBJECTIVES: The aim of this prospective, observational study was to evaluate changes in regional cerebral oxygen saturation (rSO2) and incidence of intraoperative cerebral desaturation in a cohort of elderly patients undergoing major abdominal surgery. METHODS: rSO2 was continuously monitored on the left and right sides of the forehead in 60 patients older than 65 yr (35 males and 25 females; ASA II-III; age: 72 +/- 5 yr; without pre-existing cerebral pathology, and baseline Mini Mental State Examination (MMSE) score >23) undergoing sevoflurane anaesthesia for major abdominal, non-vascular surgery >2 h. RESULTS: Baseline rSO2 was 63 +/- 8%; cerebral desaturation (rSO2 decrease <75% of baseline or <80% in case of baseline rSO2 <50%) occurred in 16 patients (26%). The MMSE decreased from 28 +/- 1 before surgery to 27 +/- 2 on 7th postoperative day (P = 0.05). A decline in cognitive function (decrease in MMSE score > or = 2 points one week after surgery as compared to baseline value) was observed in six patients without intraoperative cerebral desaturation (13.6%) and six patients who had intraoperative cerebral desaturation (40%) (P = 0.057) (odds ratio: 4.22; CI95%: 1.1-16). Median (range) hospital stay was 14 (5-41) days in patients with an area under the curve of rSO2 <50% (AUCrSO2<50%) >10 min%, and 10 (4-30) days in those with an AUCrSO2<50% <10 min% (P = 0.0005). CONCLUSIONS: In a population of healthy elderly patients, undergoing non-vascular abdominal surgery cerebral desaturation can occur in up to one in every four patients, and the occurrence of cerebral desaturation is associated with a higher incidence of early postoperative cognitive decline and longer hospital stay.     

Advantages of subclavian artery perfusion for repair of acute type A dissection.

OBJECTIVE: Arterial perfusion through the right subclavian artery is proposed to avoid intraoperative malperfusion during repair of acute type A dissection. This study evaluated the clinical and neurological outcome of patients undergoing surgery of acute aortic type A dissection following subclavian arterial cannulation compared to femoral artery approach. METHODS: From 1/97 to 1/03, 122 consecutive patients underwent surgery for acute type A aortic dissection. Subclavian cannulation was performed in 62 versus femoral cannulation in 60 patients. Clinical characteristics in both groups were similar. Mean age was 61 years (SD+/-14 years, 72% male) and mean follow-up was 3 years (+/-2 years). Patient outcome was assessed as the prevalence of clinical complications, especially neurological deficits, mortality at 30 days, perioperative morbidity and time of body temperature cooling and analyzed by nominal logistic regression analysis for odds ratio calculation. RESULTS: Arterial subclavian cannulation was successfully performed without any occurrence of malperfusion in all cases. Patients undergoing subclavian cannulation showed an odds ratio of 1.98 (95% CI 1.15-3.51; P=0.0057) for an improved neurological outcome compared to patients undergoing femoral cannulation. Re-exploration rate for postoperative bleeding was significantly reduced in the subclavian group (P<0.0001), as well as occurrence of myocardial infarction (P<0.0001) and duration for body temperature cooling (P=0.004). The 30-day mortality of patients with femoral cannulation was significantly higher compared to patients with subclavian artery cannulation (24 versus 8%; P=0.0179). CONCLUSIONS: Arterial perfusion through the right subclavian artery provides an excellent approach for repair of acute type A dissection with optimized arterial perfusion body perfusion and allows for antegrade cerebral perfusion during circulatory arrest. The technique is safe and results in a significantly improved clinical and especially neurological outcome.     

Use of near-infrared spectroscopy to monitor regional cerebral oxygen saturation during infrarenal aortic crossclamping in piglets

PURPOSE: The hemodynamic changes induced by infrarenal aortic crossclamping have been well documented, but the effects of such crossclamping on cerebral perfusion are unknown. To investigate these effects, we used near-infrared spectroscopy (NIRS) to monitor regional cerebral oxygen saturation (rSO2) during infrarenal aortic crossclamping in a piglet model. METHODS: The study involved 19 piglets, each weighing 7.8 +/- 1 kg. The NIRS sensor was placed on each animal's forehead. General anesthesia was induced, and the infrarenal abdominal aorta was mobilized through a laparotomy. After heparin (1 mg/kg) was administered, crossclamps were applied proximally and distally. A 2 mm segment was resected from the proximal aortic stump, and an aorto-aortic anastomosis was performed. RESULTS: Crossclamping lasted for 30.6 +/- 6.7 min. Between the time of baseline measurement and clamp application, the rSO2 did not decrease significantly (65.4%+/- 8.9% vs. 62.4%+/- 7.8%). However, significant decreases in the rSO2 occurred between baseline measurement and clamp removal (65.4%+/- 8.9% vs. 55.7%+/- 8.9%; P<0.01), between baseline measurement and the end of surgery (65.4%+/- 8.9% vs. 57.7%+/- 7.5%; P<0.01), and between clamp application and removal (62.4%+/- 7.8% vs. 55.7%+/- 8.9%; P<0.01). At these same intervals, no intergroup differences occurred in the temperature, heart rate, or mean arterial pressure. CONCLUSION: Infrarenal aortic crossclamping significantly decreases the rSO2. NIRS, which has the advantages of being non-invasive and continuous, may be useful for monitoring this variable intraoperatively.     

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 degrees C) CPB, and group 2 (n = 15) underwent surgery for hypothermic (30 degrees 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.     

长时间CO2气腹和Trendelenburg体位对中老年患者直肠癌根治术中脑氧饱和度的影响

目的评估腹腔镜下直肠癌根治术中长时间CO2气腹和Trendelenburg体位对中老年患者脑氧饱和度(rSO2)的影响。方法选择拟行腹腔镜下直肠癌根治术患者38例,男19例,女19例,年龄45~80岁,BMI 18~25kg/m2,ASAⅠ或Ⅱ级。根据年龄分为两组:45~64岁为中年组(M组),65~80岁为老年组(O组)。两组均常规全麻插管,记录诱导结束后10 min(T0)、Trendelenburg体位后30 min(T1)、1 h(T2)和2 h(T3)的HR、MAP、PETCO2、PaCO2、PaO2、rSO2等。采用Pearson检验分析rSO2与年龄的相关性。记录术后3 d内急性脑卒中和术后谵妄(POD)等神经系统相关不良反应的发生情况。结果与T0时比较,T1-T3时两组rSO2均明显升高(P<0.05)。T0时M组rSO2明显高于O组(P<0.05)。不同时点两组HR、MAP、PETCO2、PaCO2、PaO2差异无统计学意义。T0时rSO2与年龄呈明显负相关(r=-0.650,P<0.05)。T1、T2时rSO2与年龄未见明显相关性。T3时rSO2和年龄之间呈明显正相关(r=0.488,P<0.05)。两组术后无一例急性脑卒中和POD等神经系统相关不良反应发生。结论在需要Trendelenburg体位的腹腔镜手术中,尤其对于老年患者,应该加强rSO2监测,避免脑氧供氧需失衡带来的神经系统并发症。     

Continuous monitoring of cerebral oxygen saturation in elderly patients undergoing major abdominal surgery minimizes brain exposure to potential hypoxia

Elderly patients are more prone than younger patients to develop cerebral desaturation because of the reduced physiologic reserve that accompanies aging. To evaluate whether monitoring cerebral oxygen saturation (rSO(2)) minimizes intraoperative cerebral desaturation, we prospectively monitored rSO(2) in 122 elderly patients undergoing major abdominal surgery with general anesthesia. Patients were randomly allocated to an intervention group (the monitor was visible and rSO(2) was maintained at > or =75% of preinduction values; n = 56) or a control group (the monitor was blinded and anesthesia was managed routinely; n = 66). Cerebral desaturation (rSO(2) reduction <75% of baseline) was observed in 11 patients of the treatment group (20%) and 15 patients of the control group (23%) (P = 0.82). Mean (95% confidence intervals) values of mean rSO(2) were higher (66% [64%-68%]) and the area under the curve below 75% of baseline (AUCrSO2(2)< 75% of baseline) was lower (0.4 min% [0.1-0.8 min%]) in patients of the treatment group than in patients of the control group (61% [59%-63%] and 80 min% [2-144 min%], respectively; P = 0.002 and P = 0.017). When considering only patients developing intraoperative cerebral desaturation, a lower Mini Mental State Elimination (MMSE) score was observed at the seventh postoperative day in the control group (26 [25-30]) than in the treatment group (28 [26-30]) (P = 0.02), with a significant correlation between the AUCrSO(2) < 75% of baseline and postoperative decrease in MMSE score from preoperative values (r(2)= 0.25, P = 0.01). Patients of the control group with intraoperative cerebral desaturation also experienced a longer time to postanesthesia care unit (PACU) discharge (47 min [13-56 min]) and longer hospital stay (24 days [7-53] days) compared with patients of the treatment group (25 min [15-35 min] and 10 days [7-23 days], respectively; P = 0.01 and P = 0.007). Using rSO(2) monitoring to manage anesthesia in elderly patients undergoing major abdominal surgery reduces the potential exposure of the brain to hypoxia; this might be associated with decreased effects on cognitive function and shorter PACU and hospital stay.     

Prediction of cognitive dysfunction and patients' outcome following valvular heart surgery and the role of cerebral oximetry.

OBJECTIVE: Postoperative cognitive dysfunction (POCD) commonly develops after cardiac surgery affecting patients' outcome. Cerebral oximetry noninvasively measures regional cerebral oxygen saturation (rSO(2)) and significant correlation has been reported between intraoperative cerebral desaturation and POCD, as well as patients' outcome following coronary artery bypass grafting. However, evidence is limited in valvular heart surgery (VHS). We investigated the relationship of intraoperative rSO(2) values with POCD and length of postoperative hospitalization in patients undergoing VHS. METHODS: One hundred patients undergoing elective VHS were enrolled. Neurocognitive evaluation was performed with Mini-Mental State Examination, Trail-Making Test (Part A), and Grooved Pegboard Test at 1 day before and 7th day after surgery. During surgery, rSO(2) was continuously monitored and the incidence and duration of decrease in rSO(2) values for five consecutive minutes were recorded as follows; (1) decrease in absolute rSO(2) values to less than 50%, (2) 40%, and (3) a 20% decrease compared to baseline value. RESULTS: Twenty-three patients (23%) demonstrated POCD. We could not observe any significant differences in either the incidence or duration of decrease in rSO(2) values between patients with and without POCD. Low education level and higher baseline temperature had significant correlation with POCD. Patients with cerebral desaturation required significantly longer postoperative hospitalization. CONCLUSION: In patients undergoing VHS, POCD could not be predicted with cerebral oximetry. However, patients with intraoperative cerebral desaturation required significantly longer postoperative hospitalization and cerebral oximetry appears to be promising in terms of monitoring the brain as the index organ for systemic perfusion and improving patients' outcome.