Primary brachial vein transposition for hemodialysis access: Report of a case and review of the literature

The superiority of autogenous fistulae in patients with end‐stage renal disease, performing hemodialysis, is well established and largely accepted. However, in case that superficial veins in the upper arm are not available for fistula construction, brachial vein transposition may be a viable alternative prior to graft placement. This transposition could be done as a primary or staged procedure, depending on the vein size. We present the case of a 63‐year‐old male patient with a thrombosed arteriovenous graft in the forearm and a large brachial vein in the ipsilateral upper arm. A one‐stage (primary) brachial vein transposition was performed. The fistula, 10 months after its construction, is still patent. No complications have occurred.     

Anatomical factors associated with left innominate vein stenosis in hemodialysis patients

Central venous stenosis remains a challenge in hemodialysis patients. Venograms have shown that left innominate vein (LIV) stenosis often occurs in front of the trachea, where it crosses the aortic arch, suggesting that there may be an anatomical factor involved, such as iliac vein compression syndrome. The goal of this study was to determine whether LIV stenosis can be attributed to compression. From September 2008 to December 2011, 19 hemodialysis patients (ten women, nine men) with symptomatic venous hypertension of the upper‐left extremity were enrolled in this study. Venography and multidetector computed tomography were used to determine the location of the venous stenosis and to assess LIV anatomy. LIV diameter and the space between the sternum and aortic arch were compared between the LIV stenosis (LIVS) group (n = 9) and the non‐LIV‐stenosis (NLIVS) group (n = 10). The mean age of the cohort was 63 ± 17.3 years. The mean LIV diameter was 1.69 ± 1.55 mm in the LIVS group and 8.71 ± 2.33 mm in the NLIVS group. The space between the aortic arch and sternum was smaller in the LIVS group (4.55 ± 2.67 mm) than in the NLIVS group (15.25 ± 6.12 mm, P < 0.001). A contributing factor to LIV stenosis may be due to anatomical compression of the aortic arch behind the sternum. Preoperative noncontrast computed tomography is recommended for hemodialysis patients to exclude extrinsic compression.     

Dialysis adequacy and nutritional status of hemodialysis patients

To characterize the nutritional status of renal failure patients and its relationship with hemodialysis adequacy measured by Kt/V, a study was carried out with a population of 44 adult patients with renal failure and mean age 51+/-15 years. Anthropometric data, such as dry weight, height, arm circumference, triceps skinfold thickness, mid-arm muscle circumference, and body mass index were assessed, and biochemical tests were conducted for urea, potassium, creatinine, serum albumin, and phosphorus levels, in addition to hemogram and quarterly urea reduction rate average (Kt/V). In order to evaluate calorie intake, a dietary questionnaire on habitual daily food ingestion was administered, taking into consideration the hemodialysis date. The patients were divided into 2 separate groups for the statistical analysis, with 50% of the patients in each group: A (Kt/V<1.2) and B (Kt/V>1.2). The data were tabulated as mean and standard deviation, with differences tested by Student's t test. The correlations between variables were established by the coefficient p of Pearson. Most of the patients (43%) were considered eutrophic, based on the BMI, and presented inadequate calorie intake, corresponding to 88.5+/-24% (30.8 kcal/kg actual weight) of the total energy required and adequate protein intake, reaching 109.9+/-40% of the recommended daily allowance (1.24 g/kg of actual weight). There was a correlation of Kt/V with anthropometric parameters such as body mass index, arm circumference, and mid-arm muscle circumference. The biochemical parameters related to dialysis adequacy were albumin, ferritin, and urea (predialysis). Well-dialyzed patients presented better levels of serum albumin. There was an influence of gender and age on correlations of the analyzed variables. Female and younger patients presented better dialysis adequacy. The dialysis adequacy was related to the nutritional status and influenced by the protein intake and body composition. Gender and age had an important influence in the dialysis adequacy, as men presented lower dialysis adequacy and younger adults presented better dialysis adequacy. Further research is necessary to understand better how to facilitate effective and efficient techniques for the nutritional status assessment of hemodialysis patients.     

Upper extremity interaction with a deploying side airbag: a characterization of elbow joint loading

Computer simulations, dummy experiments with a new enhanced upper extremity and small female cadaver experiments were used to analyze the small female upper extremity response under side airbag loading. After establishing a worst case initial position, three tests were performed with the fifth percentile female hybrid III anthropometric test dummy and six experiments with small female cadaver subjects. A new fifth percentile female enhanced upper extremity was developed for the dummy experiments that included a two-axis wrist load cell in addition to the existing six-axis load cells in both the forearm and humerus. Forearm pronation was also included in the new dummy upper extremity to increase the biofidelity of the interaction with the handgrip. Instrumentation for both the cadaver and dummy tests included accelerometers and MHD angular rate sensors on the forearm, humerus, upper and lower spine. In order to quantify the applied loads to the cadaver hand and wrist from the door mounted handgrip, the handgrip was mounted to the door through a five-axis load cell and instrumented with accelerometers for inertial compensation. All six of the cadaver tests resulted in upper extremity injuries including comminuted mid-shaft humerus fractures, osteochondral fractures of the elbow joint surfaces, a transverse fracture of the distal radius and an osteochondral fracture of the lunate carpal bone. The results from the 6 cadaver tests presented in this study were combined with the results from 12 previous cadaver tests. A multivariate logistic regression analysis was performed to investigate the correlation between observed injuries and measured occupant response. Using inertially compensated force measurements from the dummy mid-shaft forearm load cell, the linear combination of elbow axial force and shear force was significantly (P=0.05) correlated to the observed elbow injuries.     

Conservative management of a lymphocele that formed shortly after creation of an arteriovenous fistula for hemodialysis

Patients with end-stage renal disease require to establish vascular access for regular hemodialysis. The creation of arteriovenous fistula (AVF) is usually a safe procedure; however, there could be complications such as bleeding, hematoma, pseudoaneurysm, thrombosis, infection, and steal syndrome. A rare complication of such vascular manipulation could be formation of lymphocele. We present a case of a 67-year-old man who presented with a progressively enlarging mass 12 days after the surgery for AVF creation at the site of surgery in the right upper arm. Ultrasonographic examination revealed a fluid-filled cystic structure measuring about 4.2 × 3.6 × 1.9 cm under the skin just above the anastomosis. The fluid was aspirated using ultrasound-guided fluoroscopy that relieved the swelling. The analysis of aspirate suggested the cyst to be a lymphocele. The mass re-enlarged to its previous size in the next 3 days. While under observation for signs of complication, regular intermittent compression and a low-fat diet completely resolved the lymphocele over the subsequent 3 months. The less common occurrence of such lymphocele post AVF creation needs to be evaluated for its potential for complication, in the absence of which the lymphocele is amenable to conservative management using regular intermittent compression and low-fat oral diet.     

Asymmetric breast enlargement minus central venous thrombosis in a hemodialysis patient

A 76-year-old woman hemodialysis patient was hospitalized for community-acquired pneumonia complicating chronic obstructive pulmonary disease. End-stage renal disease secondary to hypertension had been diagnosed at the age of 64 for which the patient was initiated on maintenance hemodialysis. Then, she received a deceased donor kidney transplant at the age of 68 that succumbed to chronic rejection 4 years later when she was restarted on hemodialysis. Hemodialysis was performed via a right subclavian vein double lumen catheter for 2 months when a right brachio-axillary graft was inserted. Severe venous congestion, swelling, and nipple tenderness of her right breast noted on admission had been increasing for 6 weeks before hospital admission. No arm swelling was evident. Initial management of the patient's pneumonia and chronic obstructive pulmonary disease consisted of intravenous ceftriaxone and albuterol inhaler to which intravenous oxacillin (1 g q 6 hr) was added for presumed right mastitis. Radiological work-up for masses and malignancies was negative. An angiogram of the right upper extremity detected stenosis of the dialysis access graft at its anastomosis with the axillary vein. Angioplasty of the stenosis was performed without incident or evidence of central vein stenosis. Rapid resolution over 10 days of the unilateral breast congestion followed without complication.     

汽车转向节臂端部冷精整工艺优化

目的 得到单向压缩冷精整的精整量与预变形孔半径和深度之间的变化规律,以及摩擦因数大小同回弹量之间的关系。方法 对转向节臂端部锻件上下表面进行预变形凹槽孔处理,并建立锻件单向压缩冷精整的弹塑性有限元模型,利用ABAQUS有限元软件进行数值模拟仿真,分析摩擦因数对表面质量的影响,得到优化后的工艺参数,并进行实验验证模拟结果的准确性。结果 摩擦因数越大,冷精整后的转向节臂端部锻件的鼓形越明显。在精整量为1 mm的情况下,当预变形凹槽孔的半径为4 mm、深度为0.3 mm、单向压缩量为1.1 mm、摩擦因数为0.2时,能够得到最好的表面质量。结论 当摩擦因数相同时,预变形凹槽孔的半径越大,径向位移越小,而回弹量基本保持不变。     

N‐acetylcysteine may improve residual renal function in hemodialysis patients: A pilot study

Clinical outcomes in chronic dialysis patients are highly dependent on preservation of residual renal function (RRF). N‐acetylcysteine (NAC) may have a positive effect on renal function in the setting of nephrotoxic contrast media administration. In our recent study, we showed that NAC may improve RRF in peritoneal dialysis patients. The aim of the present study was to investigate the effect of NAC on RRF in patients treated with chronic hemodialysis. Prevalent chronic hemodialysis patients with a residual urine output of at least 100 mL/24 hours were included. The patients were administered oral NAC 1200 mg twice daily for 2 weeks. Residual renal function was assessed at baseline and at the end of treatment using a midweek interdialytic urine collection for measurement of urine output and calculation of residual renal Kt/V and glomerular filtration rate (GFR). Residual GFR was measured as the mean of urea and creatinine residual renal clearance. Each patient served as his own control. Twenty patients were prospectively enrolled in the study. Administration of NAC 1200 mg twice daily for 2 weeks resulted in significant improvement in RRF: urine volume increased from 320 ± 199 to 430 ± 232 mL/24 hours (P < 0.01), residual renal Kt/V increased from 0.19 ± 0.12 to 0.29 ± 0.14 (P < 0.01), and residual GFR increased from 1.6 ± 1.6 to 2.4 ± 2.3 mL/minute/1.73 m² (P < 0.01). N‐acetylcysteine may improve RRF in patients treated with chronic hemodialysis.     

Effect of high‐protein supplemental therapy on subjective global assessment of CKD‐5D patients

Adequate nutrition in patients on hemodialysis is an important step for improving the quality of life. This prospective study was undertaken to monitor the nutritional status of patients who were given high‐protein supplements on malnutrition inflammation score (MIS) and to correlate with biochemical parameters in maintenance hemodialysis (MHD) patients. This prospective study was conducted on 55 chronic kidney disease patients on MHD (37 women, 18 men), aged between 21 and 67 years. Of the 55 patients, 26 patients received high‐protein commercial nutritional supplements, whereas 29 patients received high‐protein kitchen feeding. Every patient had their MIS, 24‐hour dietary recall, hand grip, mid arm circumference, triceps skin‐fold thickness at 0, 3, and 6 months. Each of the above parameters was compared between the high‐protein commercial nutritional supplement cohort and high‐protein kitchen feeding cohort, and the data were analyzed. Of the 55 patients, 82.61% of patients on high‐protein kitchen feeding group and 66.67% in high‐protein commercial nutritional supplement group were nonvegetarian (P = 0.021). According to the MIS, improvement was observed in malnutrition status from 3‐ to 6‐month period in 38.1% of patients in high‐protein commercial supplement group, whereas only in 8.7% in high‐protein kitchen feeding group (P = 0.04). Assessment showed improvement in malnutrition status with high‐protein commercial nutritional supplement, which was marked in patients with age group >65 years (P = 0.03) and in those in whom serum albumin is <35 g/L (P = 0.02). Both high‐protein kitchen feeding and high‐protein commercial nutritional supplement cohorts were observed to have improvement in overall nutritional status. Older patients >65 years with lower serum albumin levels (<3.5 g/dL) were observed to have significant improvement in nutritional status with high‐protein commercial nutritional supplements.     

Intradialytic changes of serum magnesium and their relation to hypotensive episodes in hemodialysis patients on different dialysates

Magnesium is a crucial mineral, involved in many important physiological processes. Magnesium plays a role of maintaining myocardial electrical stability in hemodialysis patients. Intradialytic hypotension is a common complication of dialysis and it is more common with acetate dialysate. The significance of the intradialytic changes of magnesium and their relation to parathyroid hormone (PTH) level and calcium changes during dialysis, and their relation to hypotensive episodes during dialysis are interesting. The aim of this work is to investigate the intradialytic changes of serum magnesium in chronic hemodialysis patients with different hemodialysis modalities and the relation to other electrolytes and to PTH, and also the relation to intradialytic hypotension. The present study was conducted on 20 chronic renal failure patients. All patients were on regular hemodialysis thrice weekly 4 hr each using acetate dialysate (group I). To study the effect of an acetate-based dialysate vs. a bicarbonate-based dialysate on acute changes of magnesium, calcium, phosphorus, and PTH during a hemodialysis session, the same patients were shifted to bicarbonate dialysis (group II). All patients were subjected to full history and clinical examination, predialysis laboratory assessment of blood urea nitrogen (BUN), serum creatinine, albumin, and hemoglobin, serial assessment of magnesium, calcium, phosphorus, and parathyroid hormone at the start of the hemodialysis session, 2 hr later, and at the end of the session, blood pH, and electrocardiogram (ECG) presession and postsession. All patients were urged to fix their dry weight, diet, and current medications. None of the patients had diabetes, neoplasia, liver disease, or cachexia, nor had they been recently on magnesium-containing drugs or previously parathyroidectomized. Hemodialysis sessions were performed by volumetric dialysis machines using the same electrolyte composition. Magnesium level significantly increased in the bicarbonate group at the end of dialysis (0 hr: 2.73+/-0.87, 2 hr: 3.21+/-1.1, and at 4 hr: 5.73+/-1.45 mg/dL, p value <0.01), while it significantly decreased in the acetate group (0 hr: 3.00+/-0.58, 2 hr: 2.26+/-0.39, 4 hr: 1.97+/-0.33 mg/dL, p value <0.01). Calcium level significantly increased in the bicarbonate group (p=0.024) but not in the acetate group. Phosphorus level significantly decreased in both acetate and bicarbonate groups. PTH level did not significantly change in either group, p value > or =0.05. Blood pH significantly increased, changing from acidic to alkaline pH, with both modalities of hemodialysis. ECG showed no significant changes during sessions with either type of dialysate. Hypotension was significantly higher in group I compared with group II (p=0.01), and this hypotension was positively correlated with a decrease in serum magnesium level in group I. Intradialytic changes in serum magnesium have no correlation with intradialytic changes in serum calcium or with PTH level. However, it was significantly correlated with hypotension during the dialysis session, especially with acetate dialysate. Further investigations are needed to determine whether or not this is true in patients using bicarbonate dialysis.     

Vascular Access in the Hemodialysis Patient – Personal Experience and Review of the Literature

There is consensus that arteriovenous (AV) fistulae represent the best choice for initial vascular access in patients suffering from chronic renal insufficiency (CRI) or end‐stage renal disease (ESRD) approaching the need of initiating hemodialysis therapy.
However, this is a challenging task in the rapidly growing population of diabetic, aged, and hypertensive patients. The preexisting damage of the vascular anatomy and the high cardiovascular comorbidity hinder construction of a well functioning arteriovenous fistula. Late referrals to the nephrologist delay access surgery and increase the use of temporary and cuffed tunneled catheters with all their potential risks.
Nevertheless, various strategies and tools exist to overcome these problems. Early referral results in venous preservation and early selection of side, site, and type of initial vascular access. Ultrasound findings are essential components of preoperative investigations. Special attention should be paid to the quality of the arteries at each section along the forearm, the elbow region, and the upper arm. Dedicated, meticulous surgery is mandatory. Fistula monitoring and elective revision of the failing AV fistula will result in increasing longevity of the blood access, and will reduce morbidity and costs.     

飞行员手臂侧向抗拉耐力的研究

此项研究使用了特殊设计的拉力装置，机械模拟在应急弹射时作用在飞行员上肢的侧向气流吹袭力，测量了１１９名飞行员在拉中央环姿态下，右手臂对侧向拉力的耐受限度。使用拉力传感器记录了脱手时作用在手上和前臂的力。测量了飞行员手的握力、身高、体重、上肢长、上臂长、前臂长和手长等参数。实验结果表明，手的握力和在手上测量的脱手力，随着飞行员年龄的增加而减少。握力对作用在手上的侧向脱手力有影响。脱手力随着飞行员握力的增加而增加。飞行员手臂对侧向拉力的耐受限度的平均值是５７４Ｎ。此项结果为设计飞行员上肢的气流吹袭防护装置提供了科学的依据。     

握力对前臂肌肉活动水平的影响

目的：评价不同强度的握力与前臂肌肉活动水平的相关性。方法：8名健康被试者参加实验,分别完成了最大自主收缩力80%MVC,60%MVC,40%MVC及20%MVC,实验记录了指浅屈肌和腕长伸肌的表面肌电信号,采用均方根的方法分析并提取表面肌电信号的幅度特征参数;运用统计分析方法比较握力水平与指浅屈肌、腕长伸肌的表面肌电的相关性,并且使用线性回归分析握力水平与相对特征值之间是否存在线性关系。结果表明指浅屈肌和腕长伸肌的表面肌电信号幅度随握力强度的增加而增加。握力水平与前臂肌肉表面肌电信号幅值存在正相关性,屈肌和伸肌对握力都有贡献,这种特征对于肌电假肢及其他应用的研究有一定帮助。     

Late‐onset Pompe's disease in a hemodialysis patient: A first case report

A 37‐year‐old hemodialysis patient appeared with unusual somnolence during 2 successive hemodialysis sessions. Blood gas analysis revealed hypercapnic respiratory failure and spirometry restrictive lung disease. After exclusion of other causes of restrictive lung disease with chest CT‐scan and cerebrum MRI, electrophysiological study revealed myopathy. Because besides lordosis and limb‐girdle gait the patient was ambulant the possibility of late‐onset Pompe's disease was set and confirmed with evaluation of α‐glucosidase activity and genetic analysis. Enzyme replacement therapy (ERT) with aglucosidase alfa was started. Due to inaccessibility of veins in the arm without the arteriovenous fistula, during the last 1 year, the patient received the ERT through the venous line of the hemodialysis circuit. Three years later the patient remains ambulant without the need of any assistant device and preserved his pulmonary function. This is the first described case of late‐onset Pompe's disease in a hemodialysis patient treated with ERT.     

Comparing frozen saphenous vein with Gore-tex in vascular access for chronic hemodialysis

Performing chronic hemodialysis in patients suffering from end‐stage renal disease needs a suitable vascular access like arteriovenous fistula in the upper limbs and bridge fistula in the upper or lower limbs, and also use of permanent and temporary catheters. The purpose of this study is to compare frozen saphenous vein versus using synthetic Gore‐tex vascular graft for A–V fistula. In the prospective randomized study, 70 patients needing for dialysis access were randomly divided into two groups. We performed the frozen saphenous vein A–V fistula in the test group and the Gore‐tex fistula in the control group. An assessment included function criteria (fistula thrill and murmur) and complications (infection and thrombosis) in planned intervals. At the end of the follow‐up period, the flow rates of all fistulas were assessed by Doppler sonography. The data were compared. Comparing the function criteria (fistula murmur and thrill) and the flow rate of the test group (frozen saphenous A–V fistula) and the control group (Gore‐tex method) showed no significant difference and also no significant difference between two groups in thrombosis. Infection rate of the Gore‐tex method was significantly high (p < 0.05). Arteriovenous fistula was an acceptable alternative in chronic hemodialysis, and frozen saphenous vein arteriovenous fistula was superior to Gore‐tex arteriovenous graft in some aspects.     

Brachial‐cephalic fistula recovered with drainage for the basilic vein: Case report

Vascular access is essential for the implementation of hemodialysis (HD). The arteriovenous fistula (AVF) can be constructed in various locations using various veins. However, the quality of the veins will influence the construction site, as well as the functioning of the AVF. Careful analysis of the vascular network allows options for the development of new fistulas presentations. We present and discuss the case of a woman aged 69 years in HD in which a brachial‐cephalic fistula with drainage to basilic vein was created, through rotation of the cephalic vein on the forearm level. This kind of access serves to prolong the time spent dialyzing through native fistulae, with their reduced complications and greater cost‐effectiveness.     

Catheter tip malposition after percutaneous placement of tunneled hemodialysis catheters

The percutaneous catheterization of central veins is increasingly used in nephrological practice as a temporary or permanent vascular access. The aim of our study was to present and to analyze episodes of catheter tip malposition during percutaneous tunneled hemodialysis catheter insertion in the large, unselected group of patients. All patients who underwent the procedure of catheter insertion in our department during year 2012 were analyzed retrospectively. One hundred four tunneled hemodialysis catheters were inserted in 101 patients. In 58 patients, the catheter was inserted at the initiation of hemodialysis therapy as the first access and in 46 the catheter was placed because of the failure of the existing one. In 68 patients, the catheter was inserted into the right internal jugular vein and in 20 patients into the left internal jugular vein (LIJV). Subclavian veins were used in five cases and femoral veins in 11 cases. Malposition of the catheter tips occurred in six patients. In all cases, the LIJV was cannulated. In two cases, the catheter tip malposition was in the right innominate vein and in four cases in the azygos vein. Our data demonstrate that with the blind insertion of tunneled hemodialysis catheters, the risk of catheter tip malposition is significantly higher with the left side insertion. As catheter insertion through the LIJV holds very high (30%) risk of the tip malposition, it should always be performed under the fluoroscopic control.     

Practical guidance for dialyzing a hemodialysis patient following acute brain injury

The incidence of acute brain injury in chronic hemodialysis patients is increasing, as the dialysis population is becoming increasingly older, often hypertensive, at risk of ischemic and/or hemorrhagic stroke, and subdural hemorrhage. Standard intermittent hemodialysis treatments typically lead to an increase in cerebral swelling, which can exacerbate underlying cerebral damage. In critically ill patients, continuous modes of renal replacement therapy may be required, but depending upon the clinical condition, simple modifications to standard intermittent therapies may suffice, and allow effective delivery of renal replacement therapy, but ensure that patient outcomes both in terms of mortality and residual functional brain damage is no different between those with normal renal function and those on the chronic dialysis program.     

Results of Daily Hemodialysis in Catanzaro: 12-Year Experience With 22 Patients Treated For More Than One Year

Since 1985, we have been treating patients with daily hemodialysis (D-HD). We report our results with 22 patients treated on D-HD and daily home hemodialysis (DHHD) for a long-term period. Patients had very good survival of native forearm arteriovenous fistula access, and upper arm access with superficialized basilic vein. One access survived 18 years: 8 years on standard hemodialysis (STND-HD) and 10 years on D-HD. Only two fistulas failed. Blood pressure control in 12 hypertensive patients was obtained without antihypertensive drugs in 8 and with fewer medications in 4. Hematocrit and hemoglobin improved in all patients. Cardiothoratic index decreased in all patients, and we noticed a reduction in the most important echocardiographic indices in 12 patients with cardiac hypertrophy: intraventricular septum thickness, left ventricle posterior wall thickness, left ventricle internal diastolic diameter, and left atrium diameter. Data also showed improvement in nutritional status. For the most part, the levels of hormones normalized, with regular menstrual cycles in women and good sexual function in men. In our experience both elderly and young patients with severe cardiovascular diseases, severe hypertension or hypotension, anemia, and nutritional problems can, with D-HD, achieve good quality of life and start work again. D-HD, in our opinion, is the treatment of choice for patients without comorbid conditions, because good metabolic control, good nutrition, and a more normal hormonal status allow them to feel well and to have an almost normal lifestyle.     

Development of the anthropomorphic robot with carbon fiber epoxy composite materials

The material for the robot structure should have high specific stiffness (stiffness/density) to give positional accuracy and fast maneuverability to the robot. Also, the high material damping is beneficial because it can dissipate the structural vibration induced in the robot structure. This cannot be achieved through conventional materials such as steel and aluminum because these two materials have almost the same specific stiffnesses which are not high enough for the robot structure. Moreover, steel and aluminum have low material dampings.

Composites which usually consist of very high specific modulus fibers and high damping matrices have both high specific stiffnesses and high material dampings. Therefore, in this work, the forearm of an anthropomorphic robot which has 6 degrees of freedom, 70 N payload and 0·1 mm positional accuracy of the end effector was designed and manufactured with high modulus carbon fiber epoxy composite because the magnitudes of the mass and moment of inertia of the forearm of an anthropomorphic robot are most important due to its farthest position from the robot base.

Two power transmission shafts which deliver the power of the motors positioned at the rear of the robot forearm to the wrist and the end effector were also designed and manufactured with high modulus carbon fiber epoxy composite to reduce weight and rotational inertia. The mass reduction of the manufactured composite forearm was 15·9 kg less than the steel forearm.

The natural frequencies and damping capacity of the manufactured composite arm were measured by the fast Fourier transform method and compared to those for the steel arm. From the test, it was found that both the fundamental natural frequency and damping ratio of the composite arm of the robot were much higher than those of the steel arm.