Orthostatic hypotension in internal medicine wards

Objectives: Most studies of orthostatic hypotension (OH) have focused on community-dwelling and institutionalized patient populations. Less is known about OH in hospitalized patients. Moreover, a comprehensive review of OH in internal medicine wards has not been published in the English literature. Our purpose is to provide current information regarding OH in internal medicine inpatients.

Methods: A comprehensive search of medical databases was performed for potentially relevant articles, using the following keywords: postural or orthostatic hypotension, with the combination of hospitalization or internal medicine. Inclusion criteria were: population of patients hospitalized for acute disorders in internal medicine or geriatric wards with a sample size of ≥50 and publication as an original full-length article in the English language. Data from 14 selected studies are reviewed, including: pathophysiology, evaluation, prevalence, manifestations, risk factors, prognosis, and management.

Results: OH is a common and often symptomatic disorder in elderly internal medicine patients. The prevalence of OH in this population ranges from 22–75%. There are substantial discrepancies between the studies reviewed regarding definitions and means of evaluating OH. OH in internal medicine wards is largely non-neurogenic and multifactorial. The main predisposing factors for OH are prolonged bed rest, hypertension, and heart failure. OH in internal medicine wards is managed mainly with non-pharmacologic interventions, and is frequently reversible.

Conclusions: In internal medicine inpatients, OH warrants attention because this disorder is common, potentially dangerous, and treatable. In the hospital setting, OH should be routinely assessed on ambulation, following the current guidelines for OH definition and meaning.     

步进式控制性低血压技术在视神经管微 创减压手术的应用

目的 探讨如何减少实施控制性低血压对视神经管减压手术患者带来的不良影响。方法 选择40例择期行视神经管减压手术的患者，随机分为A组（持续控制性低血压组）和B组（步进控制性低血压组），n =20。检测并计算手术开始时（T0）、切蝶窦前1 min（T1）、切开视神经鞘膜后1 min（T2）和送入术后恢复室后10 min（T3）的动脉-静脉乳酸含量差（Da-jvL），并进行鼻内镜术野质量评分（SESFQ）、手术时间（OT）及观察统计术后24 h内有肌肉酸痛和头痛等不良反应的患者人数。结果 两组患者T1、T2和T3时点的Da-jvL较T0均有明显增加（P <0.05），A组T1、T2和T3时点的Da-jvL明显高于B组（P <0.05），B组T2时点的Da-jvL较T1和T3有明显增加（P <0.01）；B组T1和T2时点的SESFQ评分明显高于A组（P <0.05），且B组T3时点的SESFQ评分明显低于T1和T2时点（P <0.05）；A组患者术后不良反应明显高于B组（P <0.05）。结论 步进式控制性低血压技术能有效改善围术期组织细胞不良代谢，降低不良事件的发生率，能提高视神经管减压手术患者的安全性。     

维持性血液透析患者自主神经功能异常与透析中低血压的关系

目的以心率变异性(heart rate variability,HRV)为观察指标,分析维持性血液透析(maintenance hemodialysis,MHD)患者的自主神经功能异常与透析中低血压(intradialytichypotension,IDH)的关系.方法在透析过程中同步监测患者的血压和动态心电图,依据是否发生IDH将60例患者分为2组(血压下降组和对照组),比较2组的HRV指标,其中LFn代表交感神经活性,HFn代表迷走神经活性,LF/HF代表2者之间的平衡状态.以发生IDH为结果变量,以性别、年龄、透析龄、原发病是否糖尿病、心脏指数、中心血容量占体质量百分比、超滤量占体质量百分比和透析前LFn为预测变量,建立Logistic回归模型分析LFn对IDH的预测价值.结果对照组在透析过程中LFn水平和LF/HF比值逐渐升高,且升高趋势稳定(LFn中位数:透析开始时65.47nu,210min时73.79nu,P=0.001;LF/HF中位数:开始时2.17,210min时3.98,P＜0.001),HFn的水平则逐渐减低(HFn中位数:透析开始30.06nu,210min时19.43nu,P=0.002),而血压下降组的上述指标变化趋势不稳定,其中LFn在整个透析过程中都始终低于对照组.logistic回归模型显示,在校正了上述人口学特征和临床基础情况后,LFn对IDH的发生仍有预测价值,OR值为0.943(95%CI0.894～0.966).结论维持性血液透析患者交感神经活性在透析过程不能随血容量的下降持续、稳定的增高,与IDH的发生有密切关系;透析前交感神经活性的基础水平减低是IDH的独立危险因素,表明自主神经功能异常是导致透析中低血压的重要原因之一.     

A Combination of Nifedipine and OctreotideTreatment in an HyperinsulinemicHypoglycemic Infant

Hyperinsulinemic hypoglycemia (HH) is the commonest cause of persistent hypoglycemia in the neonatal and infancy periods. Mutations in the ABCC8 and KCNJ11 genes, which encode subunits of the ATP-sensitive potassium channel in the pancreatic beta cell, are identified in approximately 50% of these patients. The first-line drug in the treatment of HH is diazoxide. Octreotide and glucagon can be used in patients who show no response to diazoxide. Nifedipine, a calcium-channel blocker, has been shown to be an effective treatment in a small number of patients with diazoxide-unresponsive HH. We report a HH patient with a homozygous ABCC8 mutation (p.W1339X) who underwent a near-total pancreatectomy at 2 months of age due to a lack of response to diazoxide and octreotide treatment. Severe hypoglycemic attacks continued following surgery, while the patient was being treated with octreotide. These attacks resolved when nifedipine was introduced. Whilst our patient responded well to nifedipine, the dosage could not be increased to 0.75 mg/kg/day due to development of hypotension, a reported side effect of this drug. Currently, our patient, now aged 4 years, is receiving a combination of nifedipine and octreotide treatment. He is under good control and shows no side effects. In conclusion, nifedipine treatment can be started in patients with HH who show a poor response to diazoxide and octreotide treatment.     

Vasopressin release induced by hypothension is blunted in patients with diabetic autonomic neuropathy

The response of arginin-vasopressin (AVP) to baroreceptor activation (tilt testing) was investigated in patients with diabetic autonomic neuropathy (DAN). The present data show that hypothension induced by upright position showed a slight increase of AVP in patients with DAN in comparison with normal subjects and diabetic patients without DAN. These findings suggest that the blunted AVP response to hypothension may be due to lesions of afferent autonomic pathways present in DAN and plays a role in the pathogenesis of postural hypothension.