A quantified description of the interactions between the native cardiovascular system and femoro-femoral versus femoro-axillary extracorporeal life support using descending thoracic aorta velocity time integral.

Extracorporeal life support (ECLS) is an important tool in managing severe cardio-circulatory and respiratory failures. The axillary and the femoral sites are the most frequently used for arterial cannulation. There is no current evidence favoring one site over the other. We tested the hypothesis that the axillary and femoral arterial cannulation site may have different effects on left ventricular (LV) outflow. Seven patients with femoro-axillary ECLS and 4 patients with femoro-femoral ECLS were prospectively studied using the Pulse-wave Doppler (PWD) velocity time integral (VTI) in the descending thoracic aorta (DTA VTI) at different short-time variations of ECLS flow rates during the ECLS weaning process. The measurements were safe and feasible in all patients. We found a directly proportional correlation between DTA VTI and ECLS flow rate for femoro-axillary cannulation (P < 0.05) and an inversely proportional correlation in the case of femoro-femoral cannulation (P < 0.05). This is the first reported utilization of DTA VTI during ECLS that could improve our understanding of the LV-aorta interactions in patients with ECLS. DTA VTI could be used as a tool, guiding weaning from ECLS.

Variations in the formation of the median nerve and its clinical correlation.

Variations in the formation of the median nerve are of interest to anatomists, radiologists, and surgeons. These variations may be vulnerable to damage in surgical operations, but their knowledge also helps in the interpretation of a nervous compression having unexplained clinical symptoms. We studied the variation in the formation of the median nerve in 87 cadavers, i.e. 174 upper limbs of formalin preserved cadavers at the department of Anatomy, Subharti medical college. We observed an additional root taking part in the formation of the median nerve in 26.4% of upper limbs, unusual low formation of the median nerve in the arm in front of the brachial artery in 18.4% of upper limbs, and median nerve formation medial to the axillary artery in 10.3% of upper limbs. Knowledge of such anatomical variations is of interest to the anatomist and clinician alike. Surgeons who perform procedures involving neoplasm or trauma repair need to be aware of these variations.

Bilateral superficial ulnar artery with high origin from the axillary artery: its anatomy and clinical significance.

The superficial ulnar artery (SUA) is a rare anatomical variant that usually arises either in the axilla or the arm and runs a superficial course in the forearm, enters the hand, and participates in the formation of superficial palmar arch. During the routine dissection of cadavers in the department of anatomy, whilst preparing the specimen for medical students, an unusual bilateral branch of the axillary artery was found in one of the cadavers: a rare variant of the artery known as SUA, which originates from the 2nd part of the axillary arteries of both sides. The SUA is a known anatomical variant, but the bilateral high origin from the 2nd part of the axillary artery is extremely unusual. Its occurrence is of great clinical importance to the surgical and radiological departments.

One-arm maximal strength training improves work economy and endurance capacity but not skeletal muscle blood flow.

Maximal strength training with a focus on maximal mobilization of force in the concentric phase improves endurance performance that employs a large muscle mass. However, this has not been studied during work with a small muscle mass, which does not challenge convective oxygen supply. We therefore randomized 23 adult females with no arm-training history to either one-arm maximal strength training or a control group. The training group performed five sets of five repetitions of dynamic arm curls against a near-maximal load, 3 days a week for 8 weeks. This training increased maximal strength by 75% and improved rate of force development during both strength and endurance exercise, suggesting that each arm curl became more efficient. This coincided with a 17-18% reduction in oxygen cost at standardized submaximal workloads (work economy), and a 21% higher peak oxygen uptake and 30% higher peak load during maximal arm endurance exercise. Blood flow assessed by Doppler ultrasound in the axillary artery supplying the working biceps brachii and brachialis muscles could not explain the training-induced adaptations. These data suggest that maximal strength training improved work economy and endurance performance in the skeletal muscle, and that these effects are independent of convective oxygen supply.

Predictors of ineffectual radial arterial pressure monitoring in valvular heart surgery.

BACKGROUND AND AIM OF THE STUDY: Unexpected sustained underestimation of the central aortic pressure by the radial arterial pressure commonly develops following cardiopulmonary bypass (CPB) in valvular heart surgery (VHS), leading to an inappropriate use of vasopressors. The study aim was to identify clinical predictors leading to a sustained inappropriate difference between the radial and femoral arterial pressure (IDRF) in VHS. METHODS: A total of 200 patients undergoing VHS was studied prospectively. Those patients who developed sustained IDRF (systolic IDRF > or =10 mmHg and/or mean IDRF > or =5 mmHg) from immediately after discontinuation of CPB until the end of the surgery were compared with patients who did not develop any IDRF. RESULTS: Data from seven patients who required second aortic cross-clamping and re-CPB were excluded from the analysis; thus, data from 193 patients were analyzed. In total, 53 patients (27.5%) developed sustained IDRF, whereas 80 patients (41.4%) did not develop any IDRF. In multivariate analysis, female gender, the presence of atrial fibrillation and diuretic use were identified as independent preoperative predictors; longer-duration aortic cross-clamping and use of larger amounts of vasopressin during CPB were identified as independent operative risk factors of the sustained IDRF. CONCLUSION: When an erroneously low radial arterial pressure is suspected following CPB in this subset of patients undergoing VHS, monitoring of the femoral or axillary arterial pressure should be considered to guide hemodynamic management, as there is an increased risk of persistence of this phenomenon.

The subscapular artery and the thoracodorsal branch: an anatomical study.

The motive for this research was the use of the muscles of the scapular region in transposition, transplantation and reparative surgery and the need for more detailed knowledge of the blood supply to these muscles. In addition, the subscapular arterial tree may be used as a source of microvascular grafts to replace damaged or diseased portions of arteries, particularly in the hand and forearm. The research was conducted on 60 sides of corpses of adults of both sexes. It was noticed that the subscapular artery was present in 96.7% of cases and originated laterally to the pectoralis minor muscle in 76.7% of cases. The average calibre was 5.0 mm, and in 73.2% of cases it measured between 4.0 and 5.9 mm. The average length was 18.0 mm, ranging from 10.0 to 29.9 mm (76.7%). It presented in its course important relations with the axillary nerve (69%) and with the radial nerve (82.8%). Its branches were collateral (subscapular muscle - 61.3%) and terminal (except for the circumflex scapular artery), leading to the following muscles: serratus anterior (43.9%), latissimus dorsi (27.6%), and subscapular (23.3%). The thoracodorsal artery, one of the terminal branches, most frequently showed a calibre of between 2.0 and 3.9 mm (70.3%), collateral branches in 85.0%, was mainly distributed to the subscapular muscle (36.7%) and to the serratus anterior muscle (29.0%) and had terminal branches to the following muscles: latissimus dorsi (44.1%), serratus anterior (40.5%) and the subscapular (12.5%). The serratus anterior muscle received one branch in 39.5% and two branches in 41.9%, while the latissimus dorsi muscle received one branch in 66.7% and two branches in 23.1%.

[Specificity of hemodynamics and endothelium-dependent vasodilation in patients with congenital thrombocytopenia].

The goal of this research was to study some particular hemodynamic parameters and the endothelium-dependent vasodilation condition in patients with inherent forms of platelet dysfunction. The discovered changes in some particular hemodynamic blood stream characteristics increase the existing qualitative defect of platelets and have prohemorrhagic directivity.

Radiation therapy impairs endothelium-dependent vasodilation in humans.

OBJECTIVES: The objective of this study was to test the hypothesis that external-beam radiation induces a chronic impairment of endothelium-dependent vasodilation. BACKGROUND: Radiation therapy is used commonly in the treatment of cancer and is associated with an increased incidence of adverse vascular events related to the field of radiation, including stroke and myocardial infarction. As endothelial injury is central to the pathogenesis of vascular diseases, we hypothesized that radiotherapy induces arterial endothelial dysfunction. METHODS: Sixteen women with unilateral breast cancer who underwent standard external-beam radiation therapy to the breast and axilla >3 years before enrollment and ten healthy women were studied. Vascular ultrasonography was used to image both the artery exposed to radiation and the contralateral artery. Flow-mediated, endothelium-dependent vasodilation and endothelium-independent vasodilation to nitroglycerin of both axillary arteries were measured. RESULTS: Endothelium-dependent vasodilation was significantly impaired in the irradiated axillary arteries compared with the contralateral, nonirradiated arteries (-0.4 +/- 0.4% vs. 3.2 +/- 0.8% p < 0.001) and also compared with control subjects' arteries (-0.4 +/- 0.4% vs. 2.5 +/- 0.6%, p < 0.001). In contrast, endothelium-independent vasodilation was greater in the arteries that received radiation compared with the contralateral arteries (3.8 +/- 0.5% vs. 2.0 +/- 0.4%, p < 0.05) and also compared with control arteries (3.8 +/- 0.5% vs. 2.5 +/- 0.4%, p < 0.05). CONCLUSIONS: External beam radiation therapy impairs endothelium-dependent vasodilation of conduit arteries, implicating a decrease in the bioavailability of nitric oxide. These abnormalities may contribute to the development of arterial occlusive disease and associated clinical events.

Axillary arterial monitoring of pediatric patients.

Use of the axillary artery for hemodynamic monitoring has gained acceptance in critically ill adults. However, there is little information concerning the safety and complications of such catheters in the pediatric population. Sixteen pediatric patients who had axillary lines placed for pressure monitoring were evaluated for neurologic and vascular function, by comparing the arm with the axillary line with the contralateral arm. There were no major complications during axillary artery monitoring. After decannulation, systolic blood pressure did not differ between arms. In a pediatric critical care environment with skilled ongoing nursing care, the axillary artery can be used as a site for intraarterial monitoring in pediatric patients without a detrimental effect on concurrent or future blood pressure monitoring.

Oxygenation of the cerebral and coronary circulation with right axillary artery perfusion during venoarterial bypass in primates.

The effectiveness of right axillary artery perform in delivering oxygenated blood to the cerebral and coronary circulation during venoarterial bypass in primates was studied. Both right and left common carotid flow measurements and arterial gas measurements revealed high flows and elevated PO2 levels. Incomplete mixing in the ascending aorta was observed from cineangiograms taken at various pump oxygenator flows in 1 animal. The results demonstrated that the brain receives excellent oxygenation at all bypass levels. However, the coronary circulation is perfused primarily by blood ejected from the left ventricle and receives only minimal contribution of well-oxygenated blood from the pump oxygenator circuit. Therefore, the heart may suffer prolonged hypoxemia during long-term venoarterial bypass for acute respiratory insufficiency.

Arterial inflow via an axillary artery graft for the severely atheromatous aorta.

BACKGROUND: Strategy for severe aortic atheromatous disease identified by intraoperative epiaortic ultrasound remains to be determined. We used axillary artery inflow through graft interposition in an attempt to avoid potential embolization. METHODS: Between July 1995 and June 1997, axillary artery inflow was used in 29 patients. Procedures performed were coronary artery bypass in 21 patients (3 with combined carotid endarterectomy), aortic valve replacement in 2, valve replacement plus coronary artery bypass in 4, atrial septal defect repair in 1, and arch replacement in 1 patient. Fibrillatory arrest was used in 16 patients and circulatory arrest was used in 16 patients for excision of mobile atheroma or arch reconstruction. Antegrade cerebral perfusion through the axillary artery graft was carried out in 11 patients. RESULTS: There were no brachial neurovascular complications. Two operative deaths occurred. Two patients had operative strokes and 2 more had postoperative stroke, all with resolution at late follow-up. There were no strokes in the subset of patients who had antegrade cerebral perfusion during circulatory arrest. CONCLUSION: The axillary artery is an excellent site for arterial inflow. Furthermore, antegrade cerebral perfusion is easily accomplished during periods of circulatory arrest. Finally, graft placement avoids potential local neurovascular complications.

Ultrasound recorded axillary artery blood flow during elbow-flexion exercise.

PURPOSE: To characterize and evaluate the repeatability of ultrasound recorded blood flow in the axillary artery during one-arm dynamic elbow flexion. METHOD: 11 healthy women (23 +/- 0.9 yr, 168 +/- 1.7 cm, 63 +/- 1.1 kg) performed 90 degrees elbow flexion in supine position. Mean maximum blood velocity was recorded by ultrasound during and after two submaximal loads, representing 16 and 24% of maximal voluntary contraction, and after exhaustion (.VO(2peak))Axillary artery diameter was measured after each workload. Each subject was examined two times 8 wk apart. Oxygen uptake was measured during exercise. Values are mean +/- SE. RESULTS: Flow was not different in the two tests. Flow was 25% higher immediately after than during exercise at the submaximal workloads. Flow immediately after .VO(2peak) was 1420 +/- 79 mL.min(-1). Axillary artery diameter after .VO(2peak) was 8% larger than at rest. Coefficient of variation ranged from 11 to 23%, coefficient of repeatability ranged from 230 mL.min(-1) at rest to 940 mL.min(-1) after exercise. Coefficient of repeatability for artery diameter was 0.09 cm; coefficient of variation for diameter was about 4% at all recording times. CONCLUSION: The present study showed that ultrasound recordings of blood flow during dynamic elbow-flexion exercise were reproducible. The method can be used to study training-induced flow changes and can detect differences of about 130 mL.min(-1). Artery diameter seemed to increase as flow and load increased.

Revascularized diabetic limbs: positional changes in regional perfusion index.

We measured pre- and postoperative ankle:brachial index (ABI), regional perfusion index (RPI = foot/chest transcutaneous oxygen tension [TcpO2]), and variation in RPI with limb elevation in 22 ischemic lower extremities of 20 patients to compare ABI and RPI measurements for quantifying limb perfusion and analyze perioperative positional changes in RPI. Measurements were compared, using t tests, with all limbs grouped according to severity of clinical ischemia and, again, according to presence or absence of diabetes. Preoperative mean and mean post-revascularization increases in ABI values ranged from 0.27 to 0.48 and 0.40 to 0.54, respectively; corresponding RPI values ranged from 0.18 to 0.45 and 0.48 to 0.60, respectively. Pre- and postoperative decreases in RPI with elevation ranged from 0.07 to 0.11 and 0.11 to 0.23, respectively. ABI and RPI values were equally effective in assessing clinical ischemia preoperatively and increased perfusion postoperatively, regardless of degree of ischemia or diabetes. Upon elevation, all limbs exhibited larger decrements in blood flow to the skin postoperatively compared to preoperatively, as estimated by RPI. However, postoperative positional decrease in RPI was greater in diabetics compared with nondiabetics (0.23 +/- 0.12 vs 0.12 +/- 0.06; P < 0.05), suggesting postoperative elevation of diabetic limbs with ischemic skin lesions may be unadvisable.

Percutaneous electrode guidance using the insulated needle for prelocation of peripheral nerves during axillary plexus blocks.

BACKGROUND AND OBJECTIVES: Short reports have noted that percutaneous prelocation is helpful in determining the anatomic course of a peripheral nerve, and, thereby, may serve as a guide for block needle insertion. We prospectively studied percutaneous electrode guidance to assist axillary brachial plexus blocks. METHODS: In 131 consecutive patients, the tip of an insulated needle emitting 5 mA was placed on the skin above and below the axillary artery to obtain a hand motor response characteristic of the median, ulnar, and radial nerves in succession. The current was reduced until all movement had ceased. The needle was then inserted toward the nerve to be blocked, decreasing the intensity from 2 mA to 0.5 mA, so that the same selected motor response was still obtained. The length of the needle inserted was noted, and 1.5% lidocaine was injected. Pain verbal analogic score (VAS) values were noted during both procedures. Complete sensory blockade was evaluated at 30 min. RESULTS: Rates of successful percutaneous electrode guidance were 94.6% for the median nerve, 89.4% for the radial nerve, 88.5% for the ulnar nerve, and 85.5% for all 3 nerves together. A significant correlation was found between the lowest percutaneous current applied and the depth of the nerve stimulated at 0.5 mA. Pain VAS values were significantly lower during percutaneous stimulation than during needle insertion (P <.05). Sensory block for all 3 nerves was noted in 92% of patients. CONCLUSIONS: Percutaneous electrode guidance using the insulated needle enabled clinicians to locate the terminal branches of the plexus in the axilla and appreciate their depth. This method could, therefore, minimize patient discomfort and perhaps the risk of nerve trauma.

Thoracic outlet arterial compression: prevalence in normal persons.

The prevalence of thoracic outlet compression of the subclavian or axillary artery was determined in both upper extremities of 130 normal individuals. Photoplethysmographic (PPG) recordings were made simultaneously in each index finger during performance of Adson, Costoclavicular, and hyperabduction maneuvers. Significant arterial obstruction resulted from one or more of these maneuvers in 78 subjects (60%) and was bilateral in 43 individuals (33%). Thoracic outlet arterial compression is common in normal persons and thus has little diagnostic value in symptomatic patients.

Transpulmonary thermodilution cardiac output measurement using the axillary artery in critically ill patients.

STUDY OBJECTIVE: To compare cardiac output (CO) as measured by the arterial thermodilution technique using only a central venous catheter and an arterial catheter inserted into the axillary artery, with conventional CO measurement with thermodilution using a pulmonary artery (PA) catheter (PAC). DESIGN: Prospective clinical study in which each patient served as his/her own control. SETTING: General ICU of a large tertiary-care teaching hospital. PATIENTS: 22 patients who required invasive hemodynamic monitoring in the ICU. INTERVENTIONS AND MEASUREMENTS: CO measurements made using the PAC (COpa) were compared to bolus arterial thermodilution measurements (COax). The significance of acute changes in the continuous CO measurements during acute hemodynamic episodes was observed. MAIN RESULTS: The correlation between the two techniques (COpa and COax) was R(2) = 0.82. There was a tendency for 5% overestimation of COpa by the COax. The SEM% (SEM/average CO) for COax and COpa was 2.6% and 3.2%, respectively. The bias between measurements was 0.27 +/- 0.67 L/min, and the limits of agreement (mean difference +/- 2 SD) from minus 1.07 L/min to 1.63 L/min. CONCLUSIONS: In critically ill patients, in whom the measurement of CO is required, arterial thermodilution, using a central vein and the axillary artery is accurate and reproducible.

[Clinical, flowmetric and radiologic study of the thoracic outlet in 95 healthy subjects: physiologic limitations and practical impact]. / Etude clinique, vélocimétrique et radiologique de la traversée thoraco-brachiale chez 95 sujets témoins: limites physiologiques et incidences pratiques.

Ninety-five healthy subjects have been examined regarding the presence of symptomatic compression of the brachial plexus and subclavian vessels (Thoracic Outlet Syndrome: TOS). Each subject was examined clinically and by Doppler flowmetry during performance of Adson, hyperabduction and abduction-external-rotation manoeuvres. In all subjects Roos test and X-ray examinations of the cervical spine and thoracic aperture were performed. The response was considered positive when the radial pulse disappeared for the clinical test, and when the flow was totally arrested for the Doppler flowmetry. Adson's manoeuvre showed a 1% clinical positive response and a 0% doppler positive response. Hyperabduction at 45 degrees showed a 0% positive response both clinically and by Doppler flowmetry; at 90 degrees, it showed positive response of 6% and 1% respectively, and at 180 degrees it showed positive responses of 40% and 11%. Abduction-external-rotation manoeuvres showed 14% clinical and 7% Doppler positive responses. The Roos test was positive for 8% of the subjects and X-ray was abnormal for 13% of the subjects. We conclude that: Doppler flowmetry is useful for the TOS diagnosis only when the clinical evaluation is abnormal. Total arrest of flow is sometimes temporary; arterial flow must be examined at least 20 seconds. Total arrest of flow is never seen during Adson manoeuvre or hyperabduction at 45 degrees or 90 degrees in healthy subjects. Clinical or Doppler perturbation is not significantly higher for healthy subjects presenting an X-ray abnormality.

[Blood flow measurement in palmar arterial arch of hand and digital arteries]. / Opredelenie krovotoka v ladonnoi arterial'noi duge i arteriiakh pal'tsev kisti.

As a result of examination of 20 healthy people by the method of ultrasound dopplerography normal values of blood flow in palmar arterial arch of the hand and digital arteries were established. In the course of examination by this method of 50 patients with various diseases of arteries of upper extremities hemodynamically responsible areas for lowering of blood flow were revealed. These were axileary artery, bifurcation of the brachial artery, both arteries of the forearm and arterial arch of the hand. Blood flow intensity in the arteries of the hand and fingers refleds the condition of collateral blood flow in the upper extremity.

Anatomic and flow dynamic considerations for safe right axillary artery cannulation.

OBJECTIVES: Neuroprotection is of paramount interest in cardiac surgery. Right axillary artery cannulation is well established in aortic surgery because it significantly improves survival and outcome, but malperfusion of the right brain after direct cannulation has been reported. Anatomically, 4 vessel segments are potentially amenable for cannulation of the subclavian and axillary arteries. Clinical studies vary widely in dissection sites and cannulation techniques. We investigated critical flow dynamics in the right brain caused by arterial inflow after direct cannulation and specified cannulation positions that provide optimal cerebral perfusion. METHODS: Distances from the lateral margin of the axillary artery and the subclavian artery to the origin of the vertebral artery were measured in 14 human corpses by a flexible ruler. We calculated the hemodynamics within the vertebral artery, depending on different positions of the cannula tip, in a computer-calculated model. RESULTS: The mean distance from the axillary artery to the vertebral artery was 8.5 cm, and the mean distance from the subclavian artery to the vertebral artery was 6.7 cm. Computed flow calculations demonstrated reversed flow in the vertebral artery when the cannula tip was positioned too close to its orifice. To ensure safe supra-aortic flow, a cannula can be inserted securely up to 6.0 cm into the axillary artery and 4.2 cm into the subclavian artery. CONCLUSIONS: Direct cannulation of the right axillary artery can lead to cerebral malperfusion, caused by an obstruction of the vertebral artery's orifice by the arterial cannula or a subclavian steal phenomenon due to flow reversal. The safety of direct axillary artery cannulation can be improved by a well-considered dissecting site and insertion length of the cannula.

Abnormal origin of posterior circumflex humeral artery and subscapular artery: case report and review of the literature / Origem anômala das artérias circunflexa posterior do úmero e subescapular: relato de caso e revisão de literatura

The subscapular, anterior circumflex, and posterior circumflex arteries arise from the third part of the axillary artery. During dissection of the right upper limb of the cadaver of a 70-year-old male, a common trunk was observed arising from the third part of the axillary artery which, after traveling for 0.5 cm, bifurcated into subscapular and posterior circumflex humeral arteries. The common trunk was crossed anteriorly by the radial nerve. The medial nerve was formed by medial and lateral roots on the medial side of the third part of the axillary artery, remaining medial to the brachial artery up to the cubital fossa and then following its usual course thereafter. Awareness of the vascular variations observed in the present case is important when conducting surgical procedures in the axilla, for radiologists interpreting angiographs, and for anatomy-pathologists studying rare findings

As artérias subescapular, circunflexa anterior e circunflexa posterior se originam da terceira parte da artéria axilar. Durante a dissecção de membro superior direito de um cadáver humano com 70 anos de idade, do sexo masculino, um tronco comum foi observado originando-se da terceira parte da artéria axilar, após um percurso de 0,5 cm, bifurcando-se em artéria subescapular e artéria circunflexa posterior do húmero. O tronco comum era cruzado anteriormente pelo nervo radial. O nervo medial era formado por raízes medial e lateral, no lado medial da terceira parte da artéria axilar, permanecendo em posição medial à artéria braquial até a fossa cubital e seguindo seu curso usual a partir de então. Conhecimento das variações vasculares observadas neste caso é importante ao executar procedimentos cirúrgicos na axila, para radiologistas que interpretam radiografias, e também para anatomo-patologistas que estudam achados raros