Interest of BIS monitoring to guide propofol infusion during the anhepatic phase of orthotopic liver transplantation

Objective

The anhepatic phase of orthotopic liver transplantation (OLT) is associated with significant changes in pharmacokinetics. The aim of this study was to compare the influence of this phase on propofol target concentrations during BIS guided target controlled infusion (TCI).

Study design

Prospective study.

Patients and methods

Eight patients aged 25 to 65 years, Child-Pugh status A-B scheduled for OLT were prospectively included. Anesthesia was performed using TCI of propofol (Diprifusor^®, Marsh pharmacokinetic model), sufentanil and cisatracurium. Propofol target concentration was adjusted to maintain BIS values between 40 and 50.

Results

To maintain stable BIS values, propofol target concentrations should be decreased during the anhepatic phase versus the dissection one (2.0 μg/ml ± 0.8 versus 3.0 μg/ml ± 0.9, p < 0.0001).

Conclusion

BIS could be useful to titrate propofol infusion during the anhepatic phase of OLT.     

Perioperative monitoring of the electrocardiogram during cerebral aneurysm surgery

Electrocardiographic (ECG) abnormalities occur frequently following a subarachnoid hemorrhage and may also occur intraoperatively and postoperatively in patients undergoing neurovascular procedures. The aim of this study was to assess the relationship between ECG changes and the neurological status of the patient, the size and the location of the aneurysm, and the influence of these changes on the cardiac and neurological outcome. The preoperative ECG was analyzed in 270 patients. Forty-five patients had intraoperative Holter monitoring. An immediate postoperative ECG was recorded in 120 patients and 60 patients had three consecutive postoperative ECGs. Preoperatively, 52% of the patients had an abnormal ECG and the incidence was highest in patients with a poorer neurological status. Most of the ECG changes involved the T wave or the ST segment. Intraoperative and postoperative changes occurred in 35 and 65% of the patients, respectively, and were independent of the studied factors. There were no documented cardiac events. The presence of an abnormal preoperative ECG did not influence the neurological outcome of the patient, but fluctuating postoperative changes were associated with a worse outcome.     

Right middle cerebral artery occlusion during endovascular embolisation of cerebral aneurysm by Guglielmi detachable coil: a case report

Right middle cerebral artery embolism by thrombus occurred in 63-year-old female during endovascular embolisation of cerebral aneurysm by Guglielmi detachable coil. Middle cerebral artery occlusion lasted for 60 minute, and haemodynamics was stable during this period. Middle cerebral artery occlusion was detected only by digital subtraction angiography and information from neurosurgeons. Middle cerebral artery blood flow was restored with thrombolytic agents. After tracheal extubation, transient confusion and seizure occurred, but cerebral infarction was not seen in postoperative CT and there was no complication. In case of endovascular embolisation of cerebral aneurysm by Guglielmi detachable coil, systemic heparinization is necessity to decrease the risk of embolism by thrombus, and anesthetist is required to pay attention to cerebral angiography to maintain, close relationship with neurosurgeons and to take measures for cerebral protection.     

异丙酚后处理对颅内动脉瘤夹闭术患者脑缺血再灌注时脑组织抗氧化作用的影响

目的 探讨异丙酚后处理对颅内动脉瘤夹闭术患者脑缺血再灌注时脑组织抗氧化作用的影响.方法 择期拟行颅内动脉瘤夹闭术患者30例,年龄26～64岁,体重53～73 ks,ASA Ⅰ或Ⅱ级,随机分为2组(n=15):对照组(C组)和异丙酚后处理组(P组).C组吸入0.5%～2.0%七氟烷,P组在开放载瘤动脉前吸入0.5%～2.0%七氟烷,开放载瘤动脉即刻靶控输注异丙酚至术毕,血浆靶浓度设为1.2μg/ml,同时下调七氟烷吸人浓度,维持BIS 40～60.于麻醉诱导前即刻(T_0)、阻断载瘤动脉即刻(T_1)、开放载瘤动脉即刻(T_2)、开放载瘤动脉后30min(T_3)、1 h(T_4)及术毕(T_5)时测定脑脊液压力,于T_0、T_3、T_5及术后24 h(T_6)时测定脑脊液F_2-异前列腺素(F_2-IsoPs)、α-生育酚(α-T)及γ-生育酚(γ-T)的浓度.结果 与T_0时比较,L_(4,5)时C组脑脊液压力降低,T_(3～5)时P组脑脊液压力降低,T_(3,5,6)时两组脑脊液α-T及γ-T的浓度降低,F_2-IsoPs浓度升高(P＜0.05);与C组比较,P组T_(3,4)时脑脊液压力降低,T_(3,5,6)时γ-T浓度升高,F_2-IsoPs浓度降低(P＜0.05).结论 异丙酚后处理可增强颅内动脉瘤夹闭术患者脑缺血再灌注时脑组织的抗氧化作用.     

Somatosensory evoked potential monitoring of temporary middle cerebral artery occlusion during aneurysm operation

Somatosensory evoked potentials (SEPs) in response to median nerve stimulation were used as a guide to cortical function during temporary occlusion of the distal M1 segment of the middle cerebral artery (MCA) in the surgical treatment of five large aneurysms of the MCA bifurcation. MCA occlusion times ranged from 8 to 19 minutes under moderate hypothermia at 28.8 degrees to 30.3 degrees C. SEPs were preserved for variable times during MCA occlusion, ranging from no increase in latency after 13 minutes of occlusion to severe deterioration after 6 minutes. In no case was MCA occlusion maintained for longer than 3 minutes in the presence of a severely disturbed SEP. Recovery of the SEP to its preoperative relationship with that of the nonoperated hemisphere was seen in all cases before the end of operation. All patients were awake after rewarming at the end of operation without any neurological deficit. Monitoring the SEP pertaining to the territory of a cerebral artery during its temporary occlusion can help avoid ischemic damage and will allow the surgeon to take advantage of the several benefits of this technique in aneurysm surgery.     

Continuous monitoring of regional cerebral blood flow during temporary arterial occlusion in aneurysm surgery

OBJECT: Temporary arterial occlusion (TAO) during aneurysm surgery carries the risk of ischemic sequelae. Because monitoring of regional cerebral blood flow (rCBF) may limit neurological damage, the authors evaluated a novel thermal diffusion (TD) microprobe for use in the continuous and quantitative assessment of rCBF during TAO. METHODS: Following subcortical implantation of the device at a depth of 20 mm in the middle cerebral artery or anterior cerebral artery territory, rCBF was continuously monitored by TD microprobe (TD-rCBF) throughout surgery in 20 patients harboring anterior circulation aneurysms; 46 occlusive episodes were recorded. Postoperative radiographic evidence of new infarction was used as the threshold for failure of occlusion tolerance. The mean subcortical TD-rCBF decreased from 27.8+/-8.4 ml/100 g/min at baseline to 13.7+/-11.1 ml/100 g/min (p < 0.0001) during TAO. The TD microprobe showed an immediate exponential decline of TD-rCBF on clip placement. On average, 50% of the total decrease was reached after 12 seconds, thus rapidly indicating the severity of hypoperfusion. Following clip removal, TD-rCBF returned to baseline levels after an average interval of 32 seconds, and subsequently demonstrated a transient hyperperfusion to 41.4+/-18.3 ml/l 00 g/min (p < 0.001). The occurrence of postoperative infarction (15%) and the extent of postischemic hyperperfusion correlated with the depth of occlusion-induced ischemia. CONCLUSIONS: The new TD microprobe provides a sensitive, continuous, and real-time assessment of intraoperative rCBF during TAO. Occlusion-induced ischemia is reliably detected within the 1st minute after clip application. In the future, this may enable the surgeon to alter the surgical strategy early after TAO to prevent ischemic brain injury.     

大脑状态指数在老年人丙泊酚靶控输注镇静深度监测中的应用

目的在丙泊酚靶控输注(TCI)镇静的老年患者,评价大脑状态指数(CSI)在无手术刺激条件下监测镇静深度的准确性及年龄的影响。方法ASAⅠ～Ⅲ级患者40例,按年龄分为老年组(E组),年龄65～79岁;中青年组(Y组),年龄20～55岁,每组20例。所行手术不限,诱导插管前均予以丙泊酚TCI镇静,直至改良清醒/镇静评分(OAA/S)为0分后5min停止,每20秒作改良OAA/S,记录CSI和TCI系统预测效应部位浓度值(CE)每变化0.1μg/ml时的数值及时间。计算在丧失语言反应及意识消失时的CE的CE05、CE50、CE95以及CSI05、CSI50、CSI95。结果随着丙泊酚预测效应部位浓度增加,两组CSI逐渐降低,并与OAA/S有较好的相关性,两组比较差异无统计学意义。当OAA/S≤3分时,E组的CSI明显高于Y组(P<0.05)。结论CSI与预测效应部位浓度、改良OAA/S呈高度相关性,可以较好地监测老年人与中青年人的镇静深度,在相同意识状态下,老年人的预测效应室浓度要低于中青年人,其CSI高于中青年人。     

Dissection of hepatic artery aneurysm after gastrectomy

Dissection of hepatic artery aneurysm is a rare but eventually lethal complication, after gastrectomy associated with ganglionic clearing out. A 72-year-old woman, who has sought such a surgery three weeks before, presented high digestive haemorrhage and hypotension. Endoscopic and scanographic investigation could not assess obvious diagnosis. Three days later, the patient had again haemoglobin depletion and collapsus, leading to hemorrhagic shock and death. Autopsy showed up hemoperitoin and dissected hepatic artery aneurysm. The main aetiology of hepatic artery aneurysm is atherosclerosis, but an abdominal surgery can be involved. Surgery and embolisation are the two possible treatments to be discussed and managed in the meantime.     

Recurrence of ruptured cerebral aneurysm during hospitalization

Summary We review 36 patients with recurrent attacks before radical surgery during hospitalization and evaluate various factors which seem to contribute to the recurrence of haemorrhage.     

异丙酚中对中低温体外循环脑氧合的影响

目的 观察异丙酚对中低温体外循环心肺转流术（CPB）期间脑氧合的影响。8方法 心内直视手术患者17例随机分为芬太尼组和异丙酚组,通过监测动脉、颈内静脉血和混合静脉血氧含量以及乳酸浓度,计算全身和脑动静脉氧含量差、氧摄取率和动静脉乳酸浓度差,分析异丙酚对CPB期间脑氧合的影响。结果 两组复温过程中动静脉氧含量差和氧摄取率均较低温时升高;异丙酚组在CPB过程中动脉－颈内静脉血氧含量差和脑的氧摄取率要高于芬太尼组（P＜0．05）,动脉－混合静脉血氧含量差和全身的氧摄取率两组差异无显著意义（P＞0．05）。CPB全过程中两组血乳酸浓度均进行性升高。结论 CPB期间应用异丙酚麻醉并不能明显改善脑氧合。CPB期间脑保护机理有其复杂性一面,不能仅停留于氧代谢平衡方面。     

Use of computerized electroencephalographic monitoring during aneurysm surgery

The clinical usefulness of intraoperative electroencephalographic (EEG) monitoring of cerebral perfusion during aneurysm surgery has received little attention, primarily due to problems with electrode placement over the operative site, which is the area of maximal risk. In this report, 27 patients undergoing surgery for anterior circulation aneurysms were monitored intraoperatively with a two-channel computerized EEG complex using a bilateral frontal-occipital montage. In 16 patients, a normal EEG pattern was observed throughout surgery; all 16 awoke neurologically intact and their postoperative angiograms did not reveal cerebral vasospasm. In the other 11 patients, one of two patterns of persistent EEG abnormalities was identified. 1) In six of these patients a marked attenuation of EEG activity was observed ipsilaterally which coincided with various intraoperative events including brain retraction, hypotension, and aneurysm dissection/clipping. Five of these six patients awoke with new neurological deficits which persisted beyond 12 hours in two, both of whom had angiographically proven vasospasm 24 hours after surgery. 2) In the remaining five patients, a distinct abnormal EEG pattern consisting of marked hyperactivity in the delta, theta, and alpha frequency ranges was observed ipsilaterally. Four of these five patients had a poor neurological outcome and vasospasm on their angiogram 24 hours after surgery. Thus, EEG monitoring which spans the operative area during aneurysm surgery is practicable and appears to be of value in the detection of compromised cerebral perfusion during aneurysm surgery. The possible significance of the two abnormal EEG patterns identified in this report is discussed.     

Understanding intent to treat analyses: An important lesson from the international cooperative study on the timing of aneurysm surgery

Background and purposeIntent-to-treat analyses (ITT) are the best way to analyze randomized clinical trials because they preserve the benefits of randomization: to provide an unbiased assessment of relative treatment effects. Yet they play a more fundamental role, which can be demonstrated with observational studies.MethodsWe use a hypothetical RCT to explain why ITT analyses are more appropriate to analyze RCT results. We review the International Cooperative Study on the Timing of Aneurysm Surgery (ICSTAS), a landmark observational study on the management of ruptured aneurysm patients. We discuss the impact of the ICSTAS lesson on the interpretation of future observational studies using Big Data.ResultsPer-protocol (or as-treated) analyses can be misleading: The ICSTAS study provided ‘as-treated’ results clearly in favour of delayed surgery, while overall management or ITT results showed no difference between early and delayed surgery. A contemporary RCT showed that early surgery was best. ICSTAS’ lesson is that observational studies can provide misleading results when intent-to-treat categories are not predefined in the first place.ConclusionIntent-to treat analyses are the most appropriate way to analyze data, whether from randomized trials or observational studies. This observation has momentous consequences. A science of medical practice is impossible without predefined questions regarding optimal care.     

Risk factors of cerebral aneurysm re-rupture during angiography

Although re-rupture of cerebral aneurysm during angiography has been reported occasionally, we have encountered 13 such patients during eight years since 1974, the incidence corresponding to 4.4 percent of 295 consecutive aneurysm patients on whom a total of 467 angiographies were performed. Extravasation on angiogram was noticed in 10 of these patients. We carefully analyzed the following factors to determine which one is significantly related to aneurysm re-rupture during cerebral angiography. The factors we investigated were sex, age, sites of ruptured aneurysm, surgical risk grade and time interval between the latest rupture of aneurysm and angiography. Our procedures of angiography were standardized as such that contrast material was injected by means of power injector and the injection pressure was adjusted at 2.5 kg/cm2 in vertebral angiography, 3 kg/cm2 in carotid angiography and 4 kg/cm2 in retrograde brachial angiography. Volume of contrast material was 6-8 ml, 10-12 ml and 30-32 ml, respectively. An incidence of re-rupture during angiography when performed within the initial 24 hours after the latest bleeding episode was 12 out of 123 angiographies (9.8%), whereas 1 out of 344 angiographies (0.3%) which were performed later than 24 hours. This difference was significant (p less than 0.001). These data were further analyzed every one hour period. It was learned that re-rupture rate was significantly high, 9 out of 45 patients (20.0%) when angiography was done within 5 hours after the latest aneurysm rupture (p less than 0.01), particularly, 8 out of 27 patients (29.6%) within 3 hours (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

七氟醚与异丙酚对颅内动脉瘤夹闭术患者脑能量代谢影响的比较

目的 比较七氟醚与异丙酚对颅内动脉瘤夹闭术患者脑能量代谢的影响.方法 择期拟行颅内动脉瘤夹闭术的患者68例,ASA分级Ⅱ级或Ⅲ级,年龄22 ～ 62岁,体重52～81 kg,Hunt- Hess 分级Ⅱ或Ⅲ级,采用随机数字表法,将其随机分为2组(n=34):异丙酚组(P组)和七氟醚组(S组).麻醉诱导时P组靶控输注异丙酚,血浆靶控浓度2.0 μg/ml,S组吸入8％七氟醚.麻醉维持时P组靶控输注异丙酚,血浆靶浓度1.5 μg/ml,S组吸入2％七氟醚.于临时阻断前5 min(T0)、临时阻断5 min(T1)、10min(T2)、15 min(T3)、动脉瘤夹闭10 min (T4)、20 min (T5)和40 min (T6)时,收集脑组织微透析液,采用邻苯二甲醛柱前衍生反相高效液相色谱分析法结合荧光法检测微透析液葡萄糖、乳酸和丙酮酸浓度,计算乳酸/丙酮酸比(L/P比).结果 与P组比较,S组T1～ T6时微透析液葡萄糖、乳酸和丙酮酸浓度升高,T2～T4时L/P比降低(P＜0.05).与T0时比较,两组T1～T6时微透析液葡萄糖浓度降低,乳酸浓度升高,T1～T4时丙酮酸浓度降低,T5、T6时丙酮酸浓度升高,T1～T5时L/P比升高(P＜0.05);与T3时比较,两组T～T6时微透析液葡萄糖浓度和丙酮酸浓度升高,L/P比降低,T5、T6时乳酸浓度降低(P＜0.05).结论 七氟醚改善颅内动脉瘤夹闭术患者脑能量代谢的效果优于异丙酚.     

The application of near-infrared oximetry to cerebral monitoring during aneurysm embolization: a comparison with intraprocedural angiography

Near-infrared spectroscopy (NIRS) has been used to monitor regional cerebral oxygen saturation (rSO2) in patients at risk of cerebral desaturation during surgical and neurointerventional procedures. However, the quantitative capabilities of the method have been questioned, as has its validation compared with jugular bulb oximetry. Here, we compare NIRS data acquired during coil embolization procedures with incidence of vasospasm as detected from angiography. Thirty-two subarachnoid hemorrhage patients underwent embolization. Bilateral SomaSensor strips (Invos 4100, Somanetics) were affixed to the forehead at constant anatomic positions, avoiding frontal sinuses and scalp hair. Mean arterial pressure, SaO2, end-tidal pCO2, temperature and Hb were held within a narrow range during the procedure. Ipsilateral angiography was performed every 10 to 15 minutes. An independent neuroradiologist classified any vasospasm in the parent vessel as mild (25% baseline), moderate (50%), severe (75%), or total (100%). Of all, 15/32 (46.9%) patients developed spasm; in 2 it was severe or total. There was no significant association between World Federation of Neurological Surgeons grade and baseline rSO2 signal (either ipsilateral or contralateral to the side of the aneurysm) (P=0.598). There was no significant association between side of aneurysm and baseline rSO2 signal (P=0.243). However, episodes of angiographic spasm were strongly associated with reduction in trend ipsilateral NIRS signal (P<0.001); furthermore, the degree of spasm (especially more than 75% vessel diameter reduction) was associated with a greater reduction in same-side NIRS signal (P<0.001) (2-level random effects regression model, Stata 8.2, Stata Corp, TX). NIRS may have a useful role to play in the detection of cerebral desaturation secondary to vasospasm during neuroendovascular procedures.     

不同麻醉深度指标在全麻镇静和镇痛监测中的比较

目的评价脑电双频指数(BIS)和电刺激-循环反应在全麻镇静和镇痛监测中的价值。方法20例择期手术全麻病人,将丙泊酚血浆靶浓度依次设定为1、2、3、4和5μg/ml,记录每一靶浓度下的BIS、SBP、DBP和HR值。维持意识消失时的效应室靶浓度,给予一次60mA强直电刺激,随后将雷米芬太尼效应室靶浓度依次设定为1、2、3、4和5ng/ml,达到每一靶浓度后给予一次同样电刺激,计算每次电刺激前后各指标的变化值(△BIS、△SBP、△DBP和△HR)。结果丙泊酚靶浓度依次增加,BIS值依次减少(P<0.05),两者之间呈负相关(r=-0.789,P<0.01)。不同雷米芬太尼靶浓度时,电刺激均未引起BIS的变化,但引起SBP、DBP和HR增加(P<0.05或P<0.01)。随着雷米芬太尼靶浓度增加,△SBP、△DBP和△HR呈下降趋势。雷米芬太尼靶浓度与△SBP和△HR之间呈负相关(r=-0.386和-0.302,P<0.05)。结论BIS对镇静药浓度变化敏感,对疼痛刺激反应差,电刺激-循环反应能够灵敏地反映镇痛水平,所以麻醉深度监测应该针对不同成分进行多指标、多方法的综合监测。     

Thermal diffusion blood flow monitoring during aneurysm surgery

Summary Cortical blood flow (CoBF) monitoring with a thermal diffusion flow probe was performed during the clipping of aneurysms of the ICA and MCA regions, on a series of patients during the acute stage of subarachnoid haemorrhage. Emphasis was placed on the CoBF recovery after temporary clip release. Since the absolute value in this technique is unreliable, recovery of blood flow after temporary clipping is represented as %CoBF according to the following equation: %CoBF recovery = (CoBF_post-CoBF_intra)/(CoBF_pre-CoBF_intra)Presumably, this parameter checks the patency of the concerned cerebral vessels during clipping and/or release. Percent recovery of more than 100%, indicating postischaemic reactive hyperaemia, was observed immediately after release of the temporary clips in 8 of the 9 cases evaluated. In one case, with prolonged temporary clipping (37 min), no immediate recovery was observed after clip release, suggesting no-reflow phenomenon. The value slowly recovered after local administration of papaverin and returned to the pre-occlusion level within 20 minutes.Thermal diffusion CoBF monitoring may be useful in detecting the possible no-reflow phenomenon, that may lead to ischaemic complication, even after successful aneurysm clipping.