Effect of pneumatic leg compression on post-induction hypotension in elderly patients undergoing robot-assisted laparoscopic prostatectomy: a double-blind randomised controlled trial

Post-induction hypotension is common and associated with postoperative complications. We hypothesised that pneumatic leg compression reduces post-induction hypotension in elderly patients undergoing robot-assisted laparoscopic prostatectomy. In this double-blind randomised study, patients were allocated randomly to the pneumatic leg compression group (n = 50) or control (n = 50). In the intervention group, pneumatic leg compression was initiated before induction of anaesthesia. In the control group, pneumatic leg compression was initiated 20 min after anaesthesia induction. The primary outcome was the incidence of post-induction hypotension in these groups. Post-induction hypotension was defined as systolic blood pressure < 90 mmHg during the first 20 min after induction. Haemodynamic variables and area under the curve of post-induction systolic blood pressure over time were assessed. Complications associated with pneumatic leg compression were recorded, including: peripheral neuropathy; compartment syndrome; extensive bullae beneath the leg sleeves; and pulmonary thromboembolism. The incidence of post-induction hypotension decreased in the pneumatic leg compression group compared with that in the control group; 5 (10%) vs. 29 (58%), respectively, p < 0.001. In the pneumatic leg compression group, the lowest systolic, diastolic and mean blood pressures 20 min after induction of anaesthesia were significantly greater than the control group. Pneumatic leg compression resulted in an increased area under the curve of systolic blood pressure in the first 20 min after induction, p = 0.001. There were no pneumatic leg compression-related complications. Pneumatic leg compression reduced post-induction hypotension in elderly patients undergoing robot-assisted laparoscopic prostatectomy, suggesting that it is an effective and safe intervention to prevent post-induction hypotension among elderly patients undergoing general anaesthesia.     

A Reminder of Methylene Blue's Effectiveness in Treating Vasoplegic Syndrome after On-Pump Cardiac Surgery

The inflammatory response induced by cardiopulmonary bypass decreases vascular tone, which in turn can lead to vasoplegic syndrome. Indeed the hypotension consequent to on-pump cardiac surgery often necessitates vasopressor and intravenous fluid support. Methylene blue counteracts vasoplegic syndrome by inhibiting the formation of nitric oxide.We report the use of methylene blue in a 75-year-old man who developed vasoplegic syndrome after cardiac surgery. After the administration of methylene blue, his hypotension improved to the extent that he could be weaned from vasopressors. The use of methylene blue should be considered in patients who develop hypotension refractory to standard treatment after cardiac surgery.     

Cerebral autoregulation is preserved in multiple system atrophy: A transcranial Doppler study.

Patients with multiple system atrophy (MSA) present large changes in blood pressure (BP) due to autonomic disturbances. We analyzed how this change may influence dynamic cerebral autoregulation (DCA). Simultaneous recordings of arterial BP (Finapres) and middle cerebral artery (MCA) blood flow velocity (BFV) (transcranial Doppler) were performed in 10 patients with MSA (61 +/- 12 yr of age) and 12 healthy volunteers (61 +/- 11 yr of age): cerebral BFV response to oscillations in mean BP was studied in the supine position by cross-spectral analysis of mean BP and mean MCA BFV. The DCA was also studied during the decrease in BP the first seconds when standing up from a sitting position by the assessment of the cerebrovascular resistance index (CR; mean BP/mean MCA BFV ratio). The MCA BFV/BP cross-spectral analysis showed a phase for the mid-frequency band (0.07-0.2 Hz) significantly larger in MSA, suggesting more active autoregulation in response to larger changes in BP. Changes in CR reflecting the rate of autoregulation, when standing did not differ between the two groups. These data suggest that dynamic cerebral autoregulation is preserved in MSA.     

常压及控制性降压下脊髓急性牵拉损伤比较研究

目的 评价控制性降压是否增加脊髓对牵拉损伤的易感性。材料与方法健康成年杂种犬6只，随机分为常压和控制性降压脊髓牵拉损伤组。观察常压及控制性降压水平下相同程度牵拉损伤后脊髓血流(SCBF)、体感诱发电位(SEP)、神经源性运动诱发电位(NMEP)改变的差异。结果 外周血有创动脉压(MABP)平均下降幅度为40．5％。经SSPS统计软件独立样本t检验，不同牵拉水平下，常压组及低压组的SCBF(％)、SEP波幅(Asep)(％)及NMEP波幅(％)无显著差异。结论 尼卡地平控制性降压不增加脊髓对牵拉损伤的易感性。     

富含血管的听神经瘤

目的探讨富含血管的听神经瘤的手术治疗。方法复习20年（1975—1995）手术治疗单侧听神经瘤90例，其中4例为富含血管的听神经瘤（HAT），与86例非富含血管的听神经瘤（NHAT），做回顾性分析，据临床表现、放射学检查、手术所见做比较。结果HAT较NHAT年轻（28±10与54±17岁）（P〈0．01），MRI显示HAT为实质性，无肿瘤囊变，多数较NHAT为大（P〈0．05）；MRI示HAT有多个代表较大引流静脉的流空效应；经皮股动脉、椎动脉造影显示HAT有广泛的肿瘤着色及早期引流静脉的充盈，并证实由椎基动脉供血。过去文献报道认为以分期手术为宜。作者在控制性低血压麻醉下，成功地完成了4例HAT的切除术，未输血，术后无明显伤残。结论HAT是一种实质性大型肿瘤，出现于青年期，血管造影能够提供特征性发现。MRI能显示肿瘤表面的流空效应而确诊。采用控制性低血压麻醉有望能一期全切除肿瘤。     

Cardiovascular collapse during anesthesia in a patient with preoperatively discontinued chronic MAO inhibitor therapy

We describe a patient in whom long-term monoamine oxidase (MAO) inhibitor therapy was discontinued 20 days before surgery with general anesthesia. This patient developed severe perioperative hypotension after administration of 10 mg of bupivacaine through an epidural catheter, which was corrected only after potent vasopressor therapy. We attribute this hemodynamic instability to attenuation of this patient's sympathetic tone based on several mechanisms: (1) residual effect of long-term administration of MAO inhibitor that caused a decrease in the number of β-adrenergic receptors (adrenergic subsensitivity due to receptor down-regulation), (2) recovered MAO activity causing effective degradation of sympathetic amines, and (3) combined attenuating effects of general and epidural anesthesia on sympathetic tone.     

Treatment Outcomes in Spontaneous Intracranial Hypotension: Do Epidural Blood Patches Stop the Leaks?

Abstract:   Spontaneous intracranial hypotension (SIH) is a postural headache syndrome unrelated to dural puncture. Because of the increasing failure of epidural blood patch (EBP) to relieve headache in SIH, we retrospectively investigated the epidemiological features and treatment outcomes in 55 cases of SIH. The study population was stratified by age and sex; continuous variables were compared for differences by t -tests; categorical variables were compared by Chi-squared analysis or Fisher exact tests. Significant differences were identified by P values of 0.05 or less. The mean age of the study population was 44 ± 12 years with a female to male ratio of 1.3:1.0. Men presented with subdural hematomas ( P  = 0.001) more often than women. Meningeal enhancement on contrast magnetic resonance imaging (MRI) was the most consistent radiographic finding. Radionuclide cisternography (RC) demonstrated thoracolumbar dural leaks in 16 of 22 patients. EBP failures were more common in patients aged 40 and younger than in older patients ( P  = 0.003). Postural headache from SIH was not uniformly responsive to EBP, and had significant comorbidities, especially in men. The management of postural headache in SIH by other techniques to restore brain position and cerebrospinal fluid dynamics should be investigated.     

贺斯预防骨水泥所致低血压的临床探讨

目的:观察6%贺斯预防骨水泥所致低血压的效果。方法:30例人工股骨头置换病人随机分为两组:Ⅰ组为6%贺斯组(n=15);Ⅱ组为平衡盐组(n=15)。在填充骨水泥前分别输入6%贺斯及平衡盐500ml,分别测定入室(基础)、填充骨水泥前1min收缩压、填充骨水泥后5min最低收缩压,并观察心率变化。结果:Ⅰ组用骨水泥后最低收缩压明显高于Ⅱ组(P<0.01)。I组低血压发生率仅为13.3%,而Ⅱ组为60%。结论:在填充骨水泥前输注胶体能有效预防骨水泥所致的低血压。     

Orthostatic blood pressure control and ageing*

Reflex haemodynamic responses to orthostatic stress are attenuated with ageing, the extent of attenuation increasing with advancing age. In 15–20% of individuals aged >65 years, the attenuation may be so marked that there is an excessive fall of blood pressure (BP) on assumption of the upright posture, sufficient on occasions to cause symptomatic cerebral hypoperfusion - this is known as ‘ageing-related’ orthostatic hypotension (AOH), a major risk factor for morbidity and mortality. Comparison of the cardiovascular responses to a variety of physiological and pharmacological stresses in healthy young and elderly subjects and in those with AOH suggests that the predominant site of the ageing-related change in cardiovascular reflex function is in the central connections of the arterial baroreflex, affecting particularly the BP buffering response. There is no evidence for ageing-related impairment of the efferent limb of the baroreflex, i. e. there is no significant ageing change in sympathetic vasomotor function or cardiac drive. Ageing-related impairment of baroreflex function also does not appear to result from either attenuation of arterial compliance or the presence of systolic hypertension, despite the epidemiological association between systolic hypertension and AOH. Better understanding of this important problem has the potential to improve the health of all elderly people.