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Effect of a splint on measures of sustained grip exertion under different forearm and wrist postures.

Despite the facts that gripping tasks have been found to be highly correlated with CTS and that splints are gaining popularity as personal protective equipment, the influence of splints on grip performance has not been determined adequately. The present study intends to investigate the influence of splints without the volar parts as well as of forearm and wrist postures on grip performances including maximal volitional contraction (MVC), maximum acceptable sustained time (MAST), cumulated exertion output (CEO), and normalized exertion level (NEL). Twenty college-student volunteers, 10 males and 10 females, were recruited. The factors of interest were gender, forearm position, wrist deviation, and splint (with and without). The forearm positions were set at 30 degrees internal shoulder rotation, 0 degrees internal shoulder rotation, and 30 degrees external shoulder rotation, the angles being measured between the sagittal plane and the long axis of dominant forearm. The wrist deviations were extension 30 degrees , neutral, and flexion 30 degrees , the angles being measured between the sagittal plane and the long axis of the grip gauge. The results indicate that the gender effect is the most dominantly significant on all evaluated response variables. Males have more MVC (220 vs. 337N), longer MAST (20.2 vs. 10.5s), and greater CEO (4306 vs. 1638Ns), but less NEL (66.6 vs. 73.9%MVC). The forearm posture is shown to be significant only on MVC. In addition, the effect of wrist posture cannot shift all responses, nor can the effect of splints. In general, a splint without volar part seems to be recommended while performing infrequent and forceful gripping tasks under the consideration of prevention, but there should be more information about the application of a splint without volar part while performing a repetitively gripping task.

Adolescent↗

Moment arms of forearm rotators.

BACKGROUND: Rotation about a longitudinal axis of the forearm has been a matter of investigation for over 100 years. However, most studies were limited to only a few muscles and to their action in specific set positions of elbow and forearm rotation. This investigation aims at determining the moment arms of muscles that contribute to pronation and supination at three different angles of elbow flexion throughout the entire range of forearm rotation. METHODS: Muscle moment arms were derived from tendon excursions that were recorded on a full-size epoxy model of the radioulnar complex. The results were verified on a fresh cadaver specimen. FINDINGS: Moment arms of all major supinators exhibit peak values in 40-50 degrees of pronation, for all three positions of the elbow. These peak values vary with elbow position, the biceps muscle showing the highest dependency with its greatest moment arm in 90 degrees of elbow flexion. The pronators show a maximum of moment arm about the neutral position, with little dependency on elbow flexion. Brachioradialis brings the pronated, or supinated forearm into the neutral position. The bow of the radius is in function comparable to the 'throw' of a crankshaft, forming a greater lever arm between the point of insertion of the muscles and the axis of rotation of the radius. INTERPRETATION: The observations drawn from this study could be of eminent value in planning rotator muscle transplantation, in understanding functional disorders after injury, and in the physical treatment of forearm rotator muscle deficiency. Reconstruction of the physiological anatomical arrangement in the treatment of injuries is strongly recommended for restoration of function.

Cadaver↗

Giant-cell tumor of the distal forearm.

PURPOSE: Many authorities express concern that giant-cell tumors of the distal forearm are more frequently recurrent and difficult to treat chiefly because of the proximity to the carpus and the resultant diminished range of motion in the hand and forearm. We have studied the results from our institution for 49 patients with giant-cell tumors of the distal forearm treated from 2 to 28 years (mean, 14 +/- 7 years) and compared the results for different methods of treatment. METHODS: Through the computer database 49 patients with giant-cell tumors of the distal forearm (46 of the radius, 3 of the ulna) were identified. By using material from patient visits, chart review, and when necessary telephone interviews it was possible to gather demographic and outcome data for the 49 patients. For the radial lesions, 15 of the patients had a marginal resection of the distal radius along with the periosteum and ligamentous structures and implantation of cadaveric allografts. Twenty-six patients had intralesional curettage and insertion of polymethylmethacrylate (PMMA) and 5 had curettage and autograft insertion. The 3 patients with ulnar lesions were treated with Darrach resections. RESULTS: There were no deaths, infections, metastases, or amputations. In addition to the 49 original surgeries, the patients required 41 additional surgical procedures, 17 of which were for recurrent disease. The greatest numbers of recurrences were in the patients who underwent curettage with autograft or PMMA implantation. Only 2 recurrences were in patients who had a marginal resection and implantation of cadaveric allografts. The overall results for the patients showed that many had mostly minor complaints referable to function or pain and that only 18 of the 49 patients were asymptomatic. CONCLUSIONS: Although the patients with distal forearm giant-cell tumors have had a difficult course in terms of local recurrence and subsequent surgeries required for treatment failures, the ultimate outcomes for both allograft transplantation and curettage and insertion of PMMA are satisfactory. The patients with complete distal radial allografts had a better record for prevention of recurrence than the patients treated with curettage and PMMA insertion but the percentages of currently asymptomatic patients are approximately the same for both series (40% [6/15], 35% [9/26]). These data support the concept that marginal resection and complete distal radial allograft implantation should be used for patients with tumors that have destroyed much of the bone and have extensive soft tissue components and that curettage and PMMA insertion should be reserved for patients where the structural alteration of the bone is minimal.

Adolescent↗

Forearm compartment syndrome in the newborn: report of 24 cases.

PURPOSE: Isolated cases of ischemia, compartment syndrome, or Volkmann's ischemic contracture in the forearm of the newborn infant have been reported in the past. The purpose of this study is to review a large series of patients with neonatal forearm compartment syndrome and to report the important clinical features. METHODS: A search of medical records from 1980 to 2000 identified 24 children with evidence of ischemia of the forearm at the time of birth. Records and images were reviewed for prenatal and birth history, maternal factors, medical conditions, pattern of involvement, treatment, and outcomes. Patients were grouped according to the extent of initial soft-tissue involvement. RESULTS: All patients presented with a sentinel forearm skin lesion. Patterns of involvement ranged from mild skin and subcutaneous lesions to dorsal and volar compartment syndrome with or without distal tissue loss. Early treatment intervention was limited to a single case in which the diagnosis of compartment syndrome was made and an emergency fasciotomy was performed with a good outcome. In other cases tissue loss, compressive neuropathy, muscle loss, and late skeletal changes were responsible for impaired function. Distal bone growth abnormality was common. CONCLUSIONS: Forearm compartment syndrome in the newborn is not as uncommon as previously thought. The skin lesion was the common, salient, initial diagnostic finding. Early diagnosis and appropriate referral led to the salvage of a functional limb in 1 of the patients in this series. The severity of the initial insult correlated with the degree of impairment in growth and function. The delayed diagnosis and treatment of an evolving compartment syndrome may compromise further final function.

Compartment Syndromes↗

Impaired forearm blood flow and vasodilator reserve in healthy postmenopausal women.

BACKGROUND: The natural process of cessation of ovarian estrogen production is associated with an increasing incidence of cardiovascular disease. OBJECTIVE: We aimed to determine whether postmenopausal women had menopause-associated vasomotor disturbances develop. METHODS: We studied the vascular forearm function using strain-gauge venous occlusion plethysmography in 12 healthy postmenopausal women (mean age +/- SD, 47 +/- 3 years; time-lapse from menopause >1 year). Twelve premenopausal subjects matched for age and biophysical characteristics were used as a control group. RESULTS: No differences were observed in heart rate or mean blood pressure between the 2 groups of women. Forearm blood flow at supine resting was lower in postmenopausal than in premenopausal women (2.4 +/- 0.8 vs 3.1 +/- 0.5 mL/100 mL/min; P <.05). Local vascular resistance was higher in postmenopausal than in premenopausal women (43.5 +/- 17.5 vs 31.1 +/- 4.3 mm Hg/mL/100 mL/min; P <.05). Moreover, peak forearm flow in response to forearm ischemia was 20.8 +/- 7.9 mL/100 mL/min in postmenopausal women and 26.6 +/- 9.7 mL/100 mL/min in premenopausal women (P <.01). Plasma concentration of noradrenaline in the supine position was significantly higher in postmenopausal than in premenopausal women (286 +/- 22 pg/mL vs 195 +/- 33 pg/mL; P <.01). Finally, a significant positive relation was revealed in postmenopausal women between the amount of vasodilator reserve (D flow) in local peripheral circulation and levels of circulating estradiol-17beta. CONCLUSIONS: Abnormalities observed in forearm blood flow and vasodilator capacity in postmenopausal women may be attributed to a critical loss of the vasodilating property of physiologic estrogen. Our data support the possibility that reduction in dilator capacity of the vasculature may contribute to the increase of cardiovascular disease after menopause.

Blood Pressure↗

Use of the radial forearm free tissue flap to treat persistent stricture after esophagogastrectomy.

BACKGROUND: Persistent stricturing or anastomotic leakage at the cervical esophagogastric anastomosis can be a troublesome complication of gastric pull-up procedures. When the stricture is the result of ischemia of the stomach, the strictures are long and often not responsive to dilatation and require large operations such as jejunal interposition or replacement with colonic pull-up. In this report we describe the use of a radial forearm flap to patch strictures. METHODS: The radial forearm flap is a fascia cutaneous flap taken from the forearm and based on the radial artery and its venae comitantes. The advantages of this flap are that it is thin and pliable, conforms easily, has excellent reliability due to the size of the feeding vessels, and has a relatively long pedicle. The vascular anastomosis can be made to several arteries and veins within the neck. The epithelial component can be made in sizes up to 10 by 20 cm. RESULTS: We have used the radial forearm flap to patch strictures in 6 patients with persistent complex strictures in the cervical region after esophagectomy. Results were excellent in 4 patients (able to eat liquids and solids without problems) and good in 1 patient (liquids okay, some problem with solids), and 1 patient died postoperatively. Follow-up is 4 months to 7 years. CONCLUSIONS: The radial forearm flap is an excellent option for handling persistent stricture after esophagogastrectomy. In many instances, this flap can be used in lieu of a jejunal interposition flap and obviates a laparotomy to harvest jejunum. The flap fits easily into the neck and conforms to the space.

Adult↗

The radial forearm free flap for head and neck reconstruction: a review.

BACKGROUND: The radial forearm free flap has become a workhorse flap in head and neck reconstruction. Its lack of bulk, ease of dissection, vascularity, and malleability are among its many advantages. PATIENTS AND METHODS: A review of 157 radial forearm free flaps performed in 155 patients between March 1988 and June 1994 at The University of Texas M.D. Anderson Cancer Center was undertaken to determine outcome. Patient age ranged from 22 to 80 years (mean 56). There were 79 men and 76 women. Follow-up ranged from 2 to 75 months. The most prevalent neoplasm was squamous cell carcinoma (n = 129). RESULTS: The most frequent tumor staging was T3, N0, M0. Various defects were observed; however, those requiring floor-of-mouth coverage were most common (n = 95). Partial or segmental mandibular resection was seen in 42. An osseous component was included in the radial forearm flap in 9 patients, and 64 patients had undergone some form of previous tumor resection. Fifty-seven patients received preoperative irradiation and 52, postoperative. The internal jugular vein (n = 131) and the external carotid artery (n = 134) were the most frequent recipient sites for microvascular anastomosis. Vein grafts were needed in 4 cases, and end-to-side anastomoses were most commonly performed. Total flap loss occurred in 7 cases (4.5%) and partial flap loss in 1 (0.6%). For total flap loss, salvage was accomplished by a second radial forearm free flap in 2 cases and alternative rotational flaps in 5. Other complications (infection, hematoma, fistula formation, etc.) were seen in 34%. Donor-site difficulties were seen in 21 cases. CONCLUSION: The radial forearm free flap offers a variety of reconstructive options for the head and neck. Its low flap loss and complication rates offer the best choice for oral lining restoration if bulk is not required.

Adult↗

Ultradistal and distal forearm bone mineral density in postmenopausal women.

OBJECTIVES: A cross-sectional study was conducted to evaluate bone mineral density of the forearm in older women. METHODS: Eight hundred and thirty-two women who had received a routine distal forearm bone mineral density screening measurement were included. Data were collected on age, age at menopause, duration of menopause, body height, body weight, and duration of hormone replacement therapy. RESULTS: After menopause the incidence of osteoporosis increased markedly with age, from 5.8% in the distal site and 3.9% in the ultradistal site less than 5 years after menopause to 61.1% and 44.4%, respectively, 25 years or later after menopause. Hormone replacement therapy markedly reduced the incidence of osteoporosis. CONCLUSIONS: After menopause, the incidence of osteoporosis in the forearm increased markedly with years. Women with higher body weight had higher forearm bone mineral density, and postmenopausal hormone replacement therapy prevented bone loss in the forearm.

Absorptiometry, Photon↗

Influence of aging and menopause in determining vertebral and distal forearm bone loss in adult healthy women.

In order to assess the relative influence of aging and menopause in determining the decrease of bone mass in adult women, two groups of normal subjects were examined in this retrospective, cross-sectional study. In group A, bone mineral density (BMD) was evaluated at spine (L2-L4) by dual X-ray absorptiometry (DXA) (Hologic QDR-1000); in group B, BMD was measured at the distal forearm by single photon absorptiometry (SPA) (Osteometer DT 100). Both groups were further divided into two subgroups: A1 and B1 included women with the same postmenopausal, but different chronological age; A2 and B2 included women with the same chronological, but different postmenopausal age. BMD and BMI-corrected BMD (cBMD) were plotted versus age and years since menopause, respectively. Mathematical analysis of the correlation curves between BMD and chronological age showed that the decrease of BMD is very similar at spine and forearm, and is better fitted by a quadratic function. Age-related fractional bone diminution shows a progressive increase with aging (at spine: -0.38%/year at 45 years, -0.81%/year at 50, -1.3%/year at 55 and -1.9%/year at 60. At forearm: -0.5%/year at 50 years, -1.1%/year at 55 and -1.68%/year at 60). On the other hand, menopause-related BMD decrement is very evident during the first year since menopause (at spine: -8.1%/year; at forearm: -3.4%/year), and progressively decreases, according to a logarithmic function. Ten years later, yearly diminution of BMD is below 1%/year and 0.4%/year at spine and forearm, respectively. At this time, age contributes to determine bone loss for 2/3 and menopause for 1/3.

Absorptiometry, Photon↗

Three-dimensional video analysis of forearm rotation before and after combined pronator teres rerouting and flexor carpi ulnaris tendon transfer surgery in patients with cerebral palsy.

The effect of combined pronator teres rerouting and flexor carpi ulnaris transfer on forearm rotation was prospectively studied by comparison of pre- and postoperative three-dimensional analysis of forearm range of motion in ten patients with cerebral palsy. One year postoperatively, surgery had improved maximal supination of the forearm in all patients by an average of 63 degrees, but there was also a mean loss of 40 degrees pronation. Forearm range of motion increased by a mean of 23 degrees. The centre of the range of motion on average shifted 52 degrees in the direction of supination. Based on these results of objective forearm range of motion analysis, we conclude that the common combination of pronator teres rerouting and flexor carpi ulnaris transfer in patients with cerebral palsy effectively facilitates active supination but impairs active pronation.

Adolescent↗

Functional results of dynamic splinting after transmetacarpal, wrist, and distal forearm replantation.

The results of replantation at the wrist and distal forearm are reported to be better than at the metacarpal level, in part because the latter involve direct injury to the intrinsic muscles. This study evaluates a new post-operative protocol for replantation at the metacarpal, wrist and distal forearm levels. 3 days after replantation, the patient was placed in a dynamic crane outrigger splint with MP joint control, compensating for intrinsic muscle function loss. From 4 to 12 weeks, an anticlaw splint alternated with the outrigger splint. After 12 weeks, a dynamic wrist extension orthosis was added to the anti-claw splint. 11 patients (four replantations at the transmetacarpal level, three at the wrist and four in the distal forearm) had this protocol between 1988 and 1993. For distal forearm replantation, TAM of fingers averaged 216 degrees, grip strength 42 lb, and pinch strength 7.2 lb with 75% good or excellent results. For wrist replantations, TAM of fingers averaged 243 degrees, grip strength 37 lb and pinch strength 10.6 lb with 100% good or excellent results. For transmetacarpal replantations, TAM of fingers averaged 189 degrees, grip strength 37 lb and pinch strength 5.6 lb, with 75% good and excellent results. Early protected mobilization, as described here, preserves tendon gliding, muscle strength and excursion. Our results support this protocol for wrist and distal forearm replantation and especially for transmetacarpal replantation, the results of which tend to be poor according to the medical literature.

Adult↗

Comparison of forearm endothelial function between premenopausal and postmenopausal women with or without hypercholesterolemia.

We sought to determine whether menopausal status or postmenopausal hypercholesterolemia affects forearm resistance artery endothelial function. We studied the forearm resistance artery endothelial function in 75 Japanese women: 25 premenopausal volunteers, 25 postmenopausal women with normal serum low-density lipoprotein (LDL) cholesterol concentrations, and 25 hypercholesterolemic postmenopausal women. Excluded from the study were patients with hypertriglyceridemia, hypertension, or diabetes, cigarette smokers. The forearm blood flow (FBF) during reactive hyperemia and after sublingual nitroglycerin (NTG) administration was measured by strain-gauge plethysmography. The serum concentrations of lipoprotein (a) [Lp(a)] were significantly higher in the hypercholesterolemic postmenopausal group than in the other two groups (P<0.01). These lipid parameters were similar between the premenopausal and postmenopausal women with normal cholesterol. The FBF responses to reactive hyperemia were significantly lower in the postmenopausal hypercholesterolemic women than in the other two groups (P<0.01). The reactive hyperemia also was impaired in the postmenopausal group with normal cholesterol as compared with the premenopausal group (P<0.01). Increases in FBF after NTG were similar between the three groups. By stepwise multivariate analysis, menopausal status and serum LDL cholesterol was the significant predictor of forearm endothelial function. These findings suggest that reactive hyperemia is impaired in forearm resistance arteries after menopause, especially in postmenopausal women with hypercholesterolemia.

Adult↗

Leg versus forearm flow: 24 h monitoring in 14 normotensive subjects and in 14 age-matched hypertensive patients confined to bed.

A circadian blood pressure rhythm has been demonstrated in the majority of subjects, even if inactive during daytime. A rhythm of leg blood flow and peripheral resistance, with higher values during sleep than during waking, has also been recently shown in subjects confined to bed. Doubts still persist on whether such a rhythm also exists in the forearm, and whether or not its trend is similar to that found in the leg. In this study, leg and forearm blood flow and resistance were monitored noninvasively every 15 min for 22 h in 14 normotensives and 14 age-matched hypertensives confined to bed. A significant blood pressure fall (normotensives, -4.8%/-6.1%; hypertensives, -7.1%/-6.3%; all P <.0001), heart rate decrease (-14.9 in the former, -10% in the latter; both P <.0001) and leg flow increase (normotensives, +47.4%, hypertensives, +36.1%; both P <.0001) were found during sleep in all subjects, because of a blood redistribution probably attributable to activation of the cholinergic system. Forearm flow was significantly higher during sleep (+26.1%, P <.0001) in the normotensives, whereas in the hypertensives a slight nocturnal decrease (-1.9%) was found. In conclusion, the hypertensives had lower leg and forearm flow than the normotensives during sleep and similar during daytime. Peripheral resistance measured in the leg and in the forearm was greater in the former than in the latter, both during sleep and during waking.

Blood Pressure↗

An anatomical study on the forearm vascular system.

The purpose of the present study was to establish the clinicoanatomical basis for the radial forearm flap. We conducted a morphometric investigation on 52 Japanese cadavers, of forearm vessels, for use in free forearm flaps. The mean inner diameter of the cephalic and median cubital veins at the interepicondylar line was 1.9 +/- 1.2 mm and 1.8 +/- 1.1 mm, respectively. Mean inner diameter of the radial artery and venae comitantes 1 cm distal to the origins of the radial and ulnar arteries was 2.3 +/- 0.5 mm and 1.6 +/- 0.5 mm, respectively. The longest segment of a superficial vein was 28.7 +/- 4.6 cm, it was measured between the basilic vein 5 cm proximal to the interepicondylar line and the cephalic vein at Lister's tubercle. The length of the radial artery was 18.1 +/- 1.7 cm. There were fewer valves in the basilic vein and cephalic vein proximal to the median cubital vein and in the brachial veins than in the distal antebrachial veins. From these results some of the clinicoanatomical considerations of forearm vessels which will form the clinicoanatomical basis of the free forearm flap should be clarified.

Adult↗

Reliability of range-of-motion measurement in the elbow and forearm.

The purpose of this study was to examine intratester, intertester, and interdevice reliability of range of motion measurements of the elbow and forearm. Elbow flexion and extension and forearm pronation and supination were measured on 38 subjects with elbow, forearm, or wrist disease by 5 testers. Standardized test methods and a randomized order of testing were used to test groups of patients with universal standard goniometers, a computerized goniometer, and a mechanical rotation measuring device. Intratester reliability was high for all 3 measuring devices. Meaningful changes in intratester range of motion measurements taken with a universal goniometer occur with 95% confidence if they are greater than 6 degrees for flexion, 7 degrees for extension, 8 degrees for pronation, and 8 degrees for supination. Intertester reliability was high for flexion and extension measurements with the computerized goniometer and moderate for flexion and extension measurements with the universal goniometer. Meaningful change in interobserver range of motion measurements was expected if the change was greater than 4 degrees for flexion and 6 degrees for extension with the computerized goniometer compared with 10 degrees and 10 degrees, respectively, if the universal goniometer was used. Intertester reliability was high for pronation and supination with all 3 devices. Meaningful change in forearm rotation is characterized by a minimum of 10 degrees for pronation and 11 degrees for supination with the universal goniometer. Reliable measurements of elbow and forearm arm movement are obtainable regardless of the level of experience when standardized methods are used. Measurement error was least for repeated measurements taken by the same tester with the same instrument and most when different instruments were used.

Adolescent↗

[Endoscopic aponeurotomy for chronic exertional compartmental syndrome of the forearm: report of 41 cases].

INTRODUCTION: Chronic exertional compartment syndrome of the forearm is probably underdiagnosed as a cause of forearm pain in the sportsman. Its pathological basis is a critical elevation of extracellular pressure. The clinical diagnosis is confirmed by measurements of intracompartmental pressures. We described a reliable original method of endoscopically assisted superficial fasciotomy for treating chronic exertional compartment syndrome of the forearm. The goal of the study is the physiological and clinical validation of this technique. STUDY DESIGN: Retrospective cohort study after the anatomical assessment of the feasibility of our endoscopically assisted fasciotomy. METHODS: Review of 41 forearm decompressions in 25 patients (23 sportsmen and 2 musicians). Follow-up of 6 months to 9 years. RESULTS: Eighty-eight percent reported an excellent or good outcome with significant reduction of pain during exercise. Three patients noted the return of their compartment syndrome and this was confirmed by new measurements of intramuscular pressure. Two of them underwent fasciectomy with excision of a hypertrophic scar of the superficial aponevrosis to good effect. COMPLICATIONS: Two hematomas and 2 lateral epicondylitis with no adverse effect on the final result. DISCUSSION: Endoscopically assisted fasciotomy is a reliable technique for reducing pain in chronic compartment exertional syndromes. It allows the large majority of patients to return to sports. It is our first choice indication in young sportsmen for syndromes of the forearm (anterior and/or posterior compartment). The limit of the technique is the current knowledge of collagenic tissues pathology as a cause of recurrence with hypertrophic aponevrotic scars.

Adolescent↗

Systemic and forearm haemodynamic and metabolic effects of racemic propranolol or D-propranolol in healthy subjects.

1. The immediate haemodynamic and metabolic effects of intravenous administration of DL-propranolol and D-propranolol were studied in healthy male subjects at rest and during dynamic forearm exercise. The dose of DL-propranolol and of D-propranolol was 0.1 and 1.0 mg/kg body weight respectively. 2. DL-Propranolol reduced heart rate significantly at rest, during forearm exercise and post-exercise, whereas D-propranolol had a lesser effect on heart rate which was significant only at the end of the exercise period. Arterial blood pressure and forearm blood flow were unchanged after either drug. 3. Both drugs reduced the release of lactate from the exercising forearm. Forearm exchange of oxygen, glucose, free fatty acids and triglycerides remained unchanged. 4. The arterial blood glucose concentration increased after D-propranolol, but was unchanged after DL-propranolol. The arterial serum free fatty acid concentration decreased after DL-propranolol, but was not changed after D-propranolol. Arterial concentrations of lactate and triglycerides were not influenced by the drugs. 5. The chronotropic response to beta-adrenoceptor blockade appears to be stereoselective, suggesting specific blockade of beta-adrenoceptors. Metabolic responses to beta-adrenoceptor blockade are difficult to explain in terms of the known adrenoceptor system and may be due to non-specific actions of beta-adrenoceptor antagonists. An exception is inhibition of lipolysis, which is probably mediated via beta-adrenoceptors.

Adult↗

Haemodynamic and metabolic effects of alpha-adrenoceptor blockade with phentolamine at rest and during forearm exercise.

The pre- and post-junctional alpha-adrenoceptor blocking agent, phentolamine, was given by intravenous infusion to eight healthy volunteers during rest, forearm exercise and post-exercise. Phentolamine produced a sustained increase in heart rate. The diastolic blood pressure decreased slightly whereas systolic and mean blood pressures remained unchanged. Phentolamine caused a marked increase in the forearm blood flow and a decrease in vascular resistance at rest and post-exercise, but did not influence the blood flow or vascular resistance in the exercising forearm. There was a small increase in arterial blood glucose concentration, and a decrease in blood alanine concentration during drug infusion. Blood lactate was not affected by phentolamine. The arterial concentrations of free fatty acids and glycerol increased, and the concentration of triglycerides decreased during phentolamine infusion. Forearm exchange of glucose, lactate, alanine, glycerol, free fatty acids, triglycerides and forearm oxygen consumption were not changed significantly. These findings corroborate the concept that alpha-adrenoceptor induced vasoconstriction plays a subordinate role in exercising skeletal muscle. All of the metabolic findings might be explained as secondary to an increased noradrenaline release during phentolamine infusion.

Adult↗