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Biomedical subjects

R W Barnes

Publications and source records attributed to R W Barnes.

At least 163 records · Page 9Linked to original sources
PubMed1977

Doppler ultrasound and supraorbital photoplethysmography for noninvasive screening of carotid occlusive disease.

Doppler ultrasound and supraorbital photoplethysmography were 95 per cent accurate in identifying or excluding significant carotid obstruction in 156 vessels of seventy-six consecutive patients undergoing arteriography. Plethysmography was more sensitive but less specific than Doppler ultrasound. These technics provide simple, rapid, and accurate detection of significant carotid occlusive disease.

Carotid Artery Thrombosis↗
PubMed1977

Prospective screening for deep vein thrombosis in high risk patients.

In 257 patients undergoing total hip replacement, gastric bypass for morbid obesity, major abdominal surgery, and major leg amputation, Doppler ultrasonic screening revealed only five instances of deep vein thrombosis. The present study suggests that Doppler screening of high risk patients is a useful alternative to routine anticoagulant prophylaxis of venous thromboembolic disease.

Abdomen↗
PubMed1977

Tactile litholapaxy--safe and efficient.

Tactile litholapaxy is a safe procedure and is not difficult to learn. It can be used for stones up to 5 cm. in diameter unless the stone is very hard. The bladder is distended with irrigating fluid, the lithotrite passed, the jaws opened, and the lower jaw depressed against the floor of the bladder and vibrated to allow the stone to roll on to it. The upper jaw is depressed against the stone, the threads at the handle are meshed, and the stone is crushed. Fragments are crushed in like manner and are then washed out through a resectoscope sheath. It is easier to do and more efficient in both length of operating time, absence of complications, and shorter hospital stay when compared with visual litholapaxy and cystolithotomy.

Humans↗
PubMed1977

Sequential circulatory changes in the circumferentially burned limb.

To assess the hemodynamic alterations in the circumferentially burned extremity, Doppler arterial examinations and Xenon-133 washout determinations of muscle blood flow (MBF) were obtained in 27 limbs. In this laboratory normal resting MBF was 2.82+/-0.86 cc/min/100 gm (mean +/- S.E.M., N=26) with no value less than 1.60 cc/min/100 gm. In 27 circumferentially burned limbs, the maximum decrement in MBF occurred by 36 hours following thermal injury. The lowest MBF value in the 11 extremities not requiring escharotomy was 1.50cc/min/100gm. Escharotomy was done in 16 extremities. Mean MBF immediately prior to escharotomy was 1.30+/-0.26cc/min/100gm and improved to 4.43+/-0.52cc/min/100gm following escharotomy (p less than 0.01). Correlation between MBF and Doppler examinations was present in 63% of all studies and in 88% of studies performed immediately before or after escharotomy. The diagnostic sensitivity of Doppler examination required audible recognition of abnormal velocity signals as well as absent velocity signals. Because the intial MBF determination or Doppler examination is not helpful in predicting which extremities will eventually require escharotomy, sequential studies should be done during the first 36-48 hours following thermal injury.

Adolescent↗
PubMed1977

The cerebrovascular Doppler examination in patients with non-hemispheric symptoms.

The cerebrovascular Doppler examination indicated a significant stenosis in only 19 of 53 patients with non-hemispheric TIA'S. There were no false negative or false positive examinations. Fourteen of 19 patients with an abnormal examination and 23 of 31 patients with a normal examination became asymptomatic after a carotid endarterectomy. Eleven patients were improved and two were unchanged. Therefore the cerebrovascular Doppler examination can not be used to predict therapeutic success or failure of carotid endarterectomy for non-hemispheric TIA's.

Adult↗
PubMed1977

Xenon-133 determination of muscle blood flow in electrical injury.

Xe-133 washout determination of muscle blood flow (MBF) was used to detect muscle ischemia in electrical injury of an experimental animal model and three patients. The control MBF of rabbit hindlimbs, which averaged 11.29 +/- 1.07 cc/min/100 gm, was significantly reduced by electrical injury, to 5.82 +/- 1.49 cc/min/100 gm (p less than 0.001). An electrical injury of 4,000 watt-seconds or greater was associated with uniform MBF less than 1.00 cc/min/100 gm and with histopathologic alterations of muscle necrosis. Thenar MBF less than 1.00 cc/min/100 gm in two patients was associated with muscle necrosis requiring distal arm amputation. The remaining patient with sequential muscle blood flows above this level had uneventful healing of hand electrical injuries. Xe-133 determination of MBF may be a useful objective technique to determine the extent of electrical injury in muscle.

Adult↗
PubMed1977

Thromboembolic complications of angiography for peripheral arterial disease: prospective assessment by Doppler ultrasound.

The incidence of thromboembolic arterial complications related to percutaneous angiography done for patients with arterial disease was assessed in 101 cases (105 procedures). There were 2 instances of anterior tibial artery obstruction and 3 of a decline in ankle pressure greater than 20 mmHg in patients with preexisting leg arterial disease. No patient evidenced symptoms of the complications. This incidence of thromboembolic accident, detected by Doppler ultrasound, is significantly less than those incidence rates noted previously, although the reasons for this difference have not yet been established.

Adult↗
PubMed1977

Choice of ophthalmic artery branch for Doppler cerebrovascular examination: advantages of the frontal artery.

One hundred normal young adult volunteers were assessed by directional Doppler ultrasound to determine which branch of the ophthalmic artery was most suitable for assessment of the patency of the extracranial internal carotid artery. Each frontal artery of all subjects had normal flow direction and response to compression of the temporal, facial, and common carotid arteries. One supraorbital artery of 2 subjects had reversed flow supplied by the ipsilateral temporal artery and was probably a palpebral artery in each of these individuals. The nasal artery carried reversed flow in 39% of the individuals and was undetectable unilaterally in 2 subjects. From these data we conclude that the frontal artery is the most suitable branch of the ophthalmic artery for Doppler ultrasonic examination. Evaluation of directional flow in the frontal artery and of the influence of compression of all branches of the external carotid artery as well as the common carotid artery is a highly reliable technique to identify significant obstruction of the extracranial internal carotid artery.

Adult↗
PubMed1977

Detection of deep vein thrombosis with an automatic electrically calibrated strain gauge plethysmograph.

A new strain gauge plethysmography was developed to permit accurate electrical calibration and automatic calculation of limb blood flow from a panel meter. This instrument was used to quantitate maximum venous outflow (MVO) in both limbs of 20 normal volunteers and 387 limbs of 195 patients with clinically suspected leg vein thrombosis. The MVO of normal subjects averaged 45 +/- 18 cc/minute/100 cc of calf tissue (mean +/- 1 SD). In 69 limbs with deep vein thrombosis documented by Doppler ultrasound and/or phlebography, the MVO averaged 17 +/- 13 cc/minute/100 cc, which was significantly less than that of normal limbs (p less than 0.001). Only three of 31 limbs with venous thrombosis above the knee had MVO above 20 cc/minute/100 cc, the lower limit of normal, for a diagnostic sensitivity of 90%. The specificity of a normal MVO in excluding deep vein thrombosis was 81%, with only a 1% rate of false-negative diagnoses above the knee. This automatic strain gauge plethysmograph has the attribute of providing rapid quantitation of limb venous hemodynamics which facilitates noninvasive diagnosis and follow-up assessment of venous disease.

Doppler Effect↗
PubMed1977

Carotid endarterectomy: is an indwelling shunt necessary?

Three hundred and four consecutive endarterectomies were performed with general anesthesia and without a temporary indwelling shunt. Eight patients (2.6%) awoke from anesthesia with a new neurological deficit. Eight additional patients later developed neurological symptoms, suggesting that the absence of a shunt did not contribute to their complication. Of these 16 patients, two (0.6%) died, nine (3.0%) had a temporary neurological deficit, and five (1.6%) had a permanent neurological deficit. A prolonged occlusion time, a stump pressure of less than 50 mm Hg, or the presence of additional carotid lesions did not show a significant statistical relationship to postoperative neurological deficit.

Adult↗
PubMed1977

Noninvasive assessment of collateral blood flow of the cerebral hemisphere by Doppler ultrasound.

Directional flow in the frontal artery, a terminal branch of the ophthalmic artery, was assessed nonivasively by Doppler ultrasound druing brief digital compression of the ipsilateral common carotid artery in 62 patients. Directional frontal artery flow during carotid compression was compared with mean distal internal carotid back pressure measured at subsequent carotid endarterectomy. Mean carotid back pressure in 28 patients with normal frontal artery flow direction during carotid compression, 68 +/- 14 millimeters of mercury, was significantly higher than that observed in 24 patients in whom frontal artery flow was completely obliterated and ten in whom frontal artery flow was reversed. Distal internal carotid back pressure exceeded 48 millimeters of mercury in all patients with normal frontal artery flow direction during carotid compression. Conversely, carotid back pressure was below 41 millimeters of mercury in all but one patient in whom frontal artery flow was obliterated or bliterated or reversed during carotid compression. The results of this study indicate that Doppler ultrasound assessment of frontal artery flow direction during simultaneous carotid compression provides a rapid, sale noninvasive estimate of the adequacy of collateral hemispheric circulation.

Arteries↗