Comparison of blood pressure measurement by Doppler and by pulse oximetry techniques.
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Blood Pressure Determination↗
Biomedical subjects
J D Baker
Publications and source records attributed to J D Baker.
Relationship of extracranial carotid occlusive disease and central retinal artery occlusion.
Central retinal artery occlusion usually results in blindness. The association between central retinal artery occlusion and extracranial carotid disease has not been clearly delineated. We reviewed the case reports of 62 patients with central retinal artery occlusion, 25 of whom underwent carotid angiography as part of the diagnostic evaluation. Fourteen of the 25 (56 percent) were found to have ipsilateral extracranial carotid disease. These patients did not generally have carotid bruits and had normal noninvasive carotid tests. Ten patients underwent ipsilateral carotid endarterectomy; these patients had either embologenic ulcerated plaque or tight stenosis of the carotid artery. There were 11 patients who showed no abnormalities on angiography. Thirteen patients who did not undergo angiography showed clinical evidence of etiologic factors, including vasculitis, an embolism of cardiac origin, and trauma. The remaining 24 patients had no diagnostic workup. Follow-up data were available in six of those patients who underwent carotid endarterectomy for a mean of 34 months; no strokes were reported. In conclusion, over half of patients with central retinal artery occlusion who undergo carotid angiography will have a carotid lesion on the ipsilateral side. This suggests that central retinal artery occlusion is a significant marker for extracranial carotid disease and should be an indication for complete carotid evaluation.
Adolescent↗
The superiority of synthetic arterial grafts over autologous veins in carotid-subclavian bypass.
From May 1964 to June 1983, 36 carotid-subclavian bypasses were done in 36 patients who had symptomatic lesions at the origin of the common carotid and/or subclavian arteries at the Center for Health Sciences of the University of California, Los Angeles. Ages ranged from 28 to 82 years (mean, 58 years). Eighteen bypasses were done with prosthetic grafts, 13 done with autogenous vein, and five were transpositions with primary anastomosis of the subclavian and carotid arteries. Follow-up was available on all patients and ranged from 9 to 156 months (mean, 51.5 months). The graft patency rate at 5 years determined by actuarial methods and documented by clinical examination, noninvasive evaluation, and/or arteriography was 94.1% for prosthetic grafts and 58.3% for vein grafts (p less than 0.01). The 5-year cerebrovascular accident (CVA) rate for patients with carotid-subclavian bypass done with prosthetic grafts was 6% in contrast to 39% for those with vein grafts (p less than 0.0545). All reconstructions done by transposition and primary anastomosis remain patent and there have been no late CVAs. We conclude that prosthetic grafts are the arterial substitute of choice in carotid-subclavian bypass. Transposition and primary anastomosis between the carotid and subclavian artery, when technically feasible, may be preferable to the use of free grafts in carotid-subclavian reconstruction.
Actuarial Analysis↗
How vascular surgeons use noninvasive testing.
A questionnaire was used to determine the patterns of use of noninvasive testing by vascular surgeons. The 494 respondents had been in practice an average of 18 years. Many of the examinations were done outside the office; 85% of laboratories used were hospital facilities. In the area of cerebrovascular testing the ocular pneumoplethysmographic techniques and the periorbital Doppler test continued to be used extensively; however, the acceptance of new technology was confirmed by the finding that 71% used some form of imaging. Arterial insufficiency of the legs was most commonly evaluated with segmental Doppler pressures and stress testing was used only in selected cases. Noninvasive tests were widely used postoperatively for the follow-up of patients. Most venous testing was aimed at the detection of acute deep venous thrombosis, and venous Doppler examination and impedance phlebography were the most widely used techniques. The data from this study document the patterns of use of the vascular laboratory. Unexpected findings included the widespread use of imaging (especially duplex scanning) and the frequent use of multiple tests for cerebrovascular evaluation.
Arteries↗
Captopril enhances aminoglycoside nephrotoxicity in potassium-depleted rats.
We demonstrated that potassium depletion significantly increased gentamicin nephrotoxicity in Sprague-Dawley rats (100 mg X kg-1 X day-1). To determine whether this enhanced toxicity was mediated by renin secretion, we evaluated the effect of a converting enzyme inhibitor in this model. When we administered the combination of captopril (100 mg X kg-1 X day-1) and gentamicin in potassium-depleted rats, we observed a surprising and significant adverse effect of this combination on the clearances of inulin (CIn) and PAH (CPAH) and renal blood flow (RBF). Pretreatment with indomethacin significantly improved CIn and CPAH, and potassium repletion abolished this effect entirely. In potassium-depleted animals that received both gentamicin and captopril, the intra-arterial administration of imidazole, a thromboxane synthetase inhibitor, significantly reduced urinary TXB2 excretion and significantly improved RBF and CIn in vivo. In the same group of animals, administration of the kallikrein antagonist aprotinin also significantly increased both RBF and CIn. To measure total renal thromboxane B2 production (TXB2), we perfused kidneys ex vivo with cell-free perfusate. Three groups of animals were studied: potassium-repleted control animals, potassium-depleted control animals, and potassium-depleted animals treated with gentamicin alone, captopril alone, or the combination of gentamicin and captopril. We measured TXB2 in renal venous effluent by radioimmunoassay. Ex vivo perfused kidneys from potassium-depleted control animals produced significantly more TXB2 than potassium-repleted controls. Kidneys from potassium-depleted animals that received both gentamicin and captopril produced significantly greater amounts of TXB2 than did kidneys from potassium-depleted animals treated with captopril alone, gentamicin alone, or control potassium-depleted kidneys. The administration of imidazole ex vivo at a rate equivalent to in vivo administration (10 microM/min) reduced TXB2 production by potassium-depleted kidneys that received the combination of gentamicin and captopril to that of potassium-repleted control kidneys. These results suggest that the deleterious effect of captopril in potassium-depleted rats that received gentamicin is due at least in part to kinin-stimulated renal TXB2 production.
Aminoglycosides↗
Analysis of learning style.
Analysis of learning style, a relatively new technique in the field of education, is being used in grade school and college, as well as in graduate and postgraduate training programs. The trend in the health professions to emphasize continuing education has created a need for individual practitioners to understand the principles of self-education. Analysis of learning style is useful in this regard. It also provides a basis for teaching task-specific cognitive skills to those in residency training. In this article we review the conceptual evolution of learning style analysis, especially its use in the health professions, and describe the Kolb Learning Style Inventory (LSI), which we use to study 205 anesthesia personnel.
Allied Health Personnel↗
Acute renal dysfunction after major arteriography.
The incidence of acute renal dysfunction (ARD) after major arteriography was evaluated by assessment of the change in serum creatinine in 364 patients undergoing arteriography. Major arteriography was defined as abdominal aortography, abdominal aortography with lower-extremity runoff, aortic arch studies, or aortic arch plus selective carotid angiography. The influence of the volume of contrast material received, hydration, and associated risk factors was evaluated. In the entire group, the frequency of postarteriographic ARD was 7.1%. Although most patients recovered, 1.4% required renal dialysis. The frequency of renal dysfunction was significantly higher in patients with preexisting renal disease (14.8%), and 3.7% of these patients went on to require dialysis. In the total group and in those with normal renal function prearteriographically, the frequency of ARD was found to be related to the volume of iodinated contrast material received. Hydration before, during, and after angiography did not prevent this complication. Several risk factors, namely preexisting renal disease, advanced age, volume of contrast material used, type of study performed, diabetes mellitus, and coexistent heart disease were found to be associated with a statistically significant increased risk of postangiographic ARD.
Acute Kidney Injury↗
Research projects. Obtaining AORN endorsement and funding.
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Budgets↗
Local anesthesia.
In summary, many surgical procedures may be safely and comfortably performed utilizing regional anesthesia if only a few guidelines are followed as to choice and usage of local anesthetics. The success of a regional block will always be dependent upon correct needle placement by an experienced physician with good technical skills. However, the safety of the patient is not solely a function of experience. Modern local anesthetic preparations are reliable enough and simple enough to use that all physicians should be capable of achieving optimal patient safety at all times. If placed in a position which seems to require unfamiliar knowledge or expertise, the practitioner need only seek a consultant anesthesiologist for assistance. Plastic surgery is recognized as a specialty that frequently utilizes local anesthetics for office and outpatient procedures. The manner in which these drugs are used or abused determines their clinical reputation as well as that of the physician. It is important to promote a correct understanding of local anesthetic compounds, not only among ourselves as physicians, but also among our patients, who are becoming ever more knowledgeable of medical practice as time goes on.
Anesthesia, Local↗
Evaluation of impotence in older men.
Careful evaluation was carried out in 93 men older than 50 with erectile dysfunction. Their mean age was 61 years and the disorder had been present for a mean of 4.5 years. While 14 men (15%) had psychosocial factors that may have been pertinent, only 2 scored poorly on an Affect Balance Scale and 3 were receiving psychoactive medications. Results of nocturnal penile tumescence were abnormal in 91%. In 39% penile-brachial pressure indices were suggestive of pelvic vascular disease and in 9% were consistent with a pelvic "steal syndrome." Pelvic or peripheral nerve conduction disorders were also commonly seen in 54%. Endocrinopathy may have contributed to the dysfunction in 35%. Twenty-one men had diabetes mellitus, two new cases of hypothyroidism were discovered and hypogonadism was diagnosed definitely in four and considered likely in five others. Coexisting medical conditions were found in more than 90% of the men, especially hypertension, use of antihypertensive medications and atherosclerotic disease. Previous prostatectomies (19%) and vasectomies (30%) were common in the surgical histories. Given the wide range of disorders uncovered in older men complaining of impotence, diagnostic study of potential causes may lead to a more rational approach for the evaluation and management of these men.
Aged↗
Learning style analysis in surgical training.
Learning style analysis is being used at many educational levels to individualize the instructional process. The Kolb Learning Style Inventory (LSI) in particular has been employed to determine the learning preferences of medical students and physicians in family practice, internal medicine, and anesthesiology. This investigation was undertaken to discover whether there exists a characteristic learning profile for surgery as a specialty. The Kolb LSI was administered to 39 surgical personnel. Kolb's Converger was the preferred learning style type of the study group (46%). Accommodator (26%) and Assimilator (20%) were next, followed by Diverger (8%). These results suggest that there is an identifiable surgical learning style that can provide a referential basis for teaching and counseling during residency training.
Education, Medical↗
Polytetrafluoroethylene grafts as the first-choice arterial substitute in femoropopliteal revascularization.
We studied a series of femoropopliteal bypass operations in which polytetrafluoroethylene (PTFE) grafts were used as the first choice, regardless of the availability of saphenous vein. From Jan 1, 1979 to Dec 31, 1982, 63 PTFE femoropopliteal bypass grafts were placed in 55 patients without exploration of the saphenous vein. Forty-three grafts were placed for limb salvage, and 20 grafts were placed for disabling claudication. Patients were followed up for nine to 53 months (average, 23 months). The operative mortality was 1.8%. There were no infections. The overall patency at 30 months was 76.1%. The 30 months' cumulative patency rate for patients with claudication was 89.3%, and there were no amputations. The cumulative 30-month patency for limb salvage was 70.1%, and there was a limb salvage rate of 81.2%. Because the 30-month results were comparable with reported series using autogenous saphenous vein, we concluded that PTFE conduits may be considered the first-choice arterial substitute for femoropopliteal reconstruction. Until longer follow-ups are available, reversed autogenous saphenous vein should probably be the graft of first choice in younger patients (less than 60 years of age) without coronary artery disease who are undergoing femoropopliteal revascularizations.
Aged↗
Determinants of failure in the treatment of ruptured abdominal aortic aneurysm.
One must identify those fatal errors in the treatment of patients with ruptured abdominal aortic aneurysms (AAAs) to improve future treatment and reduce mortality. Our vascular registry identified 29 patients with ruptured AAAs who died following admission to the UCLA Hospital, Los Angeles, and the Sepulveda (Calif) Veterans Administration Hospital between 1971 and 1981. Review of the records identified four categories of error that contributed to death. These included failure to proceed with elective aneurysmectomy in 12 patients with known AAAs, error in the diagnosis of aortic rupture that led to delay in getting nine patients to the operating room, intraoperative technical error that produced venous injury in eight patients, and undue delay in anesthetic induction in four patients. Following the outline of a careful treatment approach should further reduce the mortality in the treatment of patients with ruptured AAAs.
Aged↗
Analysis of femoral artery Doppler signals by LaPlace transform damping method.
The LaPlace transform damping (LTD) method of common femoral artery Doppler waveform analysis is a new method for assessing aortoiliac stenosis. A microcomputer was used to analyze the waveform to determine the value of the damping parameter, which is related to inflow stenosis. The study included 60 limbs with arterial disease and 20 limbs in normal control subjects. With a damping value of 0.60 used as the cutoff point between nonocclusive lesions and iliac stenoses of greater than 50% diameter reduction, we found a sensitivity of 100% and a specificity of 93% (overall accuracy 95%). Unlike Doppler waveform analysis by the pulsatility index method, the accuracy of the LTD method is not affected by occlusion of the superficial femoral artery. The Doppler signal processor and the computer currently used for the LTD analysis are simple to operate and fully suitable for routine use in a clinical vascular laboratory. Our experience indicates that the LTD method of waveform analysis provides the best noninvasive method for detection of significant inflow disease.
Aorta, Abdominal↗
Bacteriologic and surgical determinants of survival in patients with mycotic aneurysms.
Mycotic aneurysms are a fulminant infectious process frequently resulting in rupture and death if not properly treated. A review of the University of California, Los Angeles, medical records identified 10 patients with extrathoracic, extracranial mycotic aneurysms. In addition, a search of the English literature revealed 178 patients with 243 mycotic aneurysms. These patients were reviewed to identify the aneurysm location, etiology, bacteriology, and modality of treatment in order to determine the relationship between these factors and the outcome. The femoral artery was the most common site (38%), followed by the abdominal aorta (31%). Arterial trauma was the primary etiology in 42% of mycotic aneurysms. In 25% no clear source of infection could be identified. Staphylococcus aureus was cultured from 28% of mycotic aneurysms, and Salmonella from 15%. A trend toward the involvement of more gram-negative aerobes and anaerobes is noted. Aortic aneurysms were repaired with in situ Dacron in 61% of patients with a 32% mortality rate and 16% reinfection rate. Simple ligation of femoral artery mycotic aneurysms resulted in a 34% incidence of ischemia necessitating amputation. Methods of treatment of superior mesenteric, carotid, iliac, and peripheral arteries are also analyzed. On the basis of these data, specific surgical procedures are recommended for the treatment of mycotic aneurysms.
Adolescent↗
Variability of carotid bruit spectral analysis.
The reproducibility of determination of stenosis of the carotid artery by bruit spectral analysis was studied in 20 patients with 29 cervical bruits. The tests were performed with the Spectraview, a dedicated microcomputer which performs the analysis by the method of Lees. The estimated residual lumen was calculated from the break frequency of the power spectrum at peak systole. Each patient was studied on five separate occasions during a week. The lowest day-to-day variation was found with those lesions with the smallest residual lumen diameter. Six patients with wide ranges had major swings of blood pressure or pulse. When the bruit analysis results from days with similar blood pressure and pulse were compared, there was a low variability. The lesser stenoses had a wider spread of break frequency, but in this range, the variation represented only small differences in lumen diameter. The results of this study indicate that bruit spectral analysis can estimate the residual lumen diameter with an acceptable day-to-day variation.
Aged↗
The limitations of predictability of success of femoral-popliteal bypass grafts.
This study was carried out to determine whether we could develop a model to identify predictive factors for success of femoral-popliteal (FP) bypass grafts. In a retrospective review of 199 operations, 24 factors influencing outcome were selected by stepwise logistic regression analysis, a sophisticated, multifactorial computer program. The top five indicators (excluding intraoperative technical problems) were runoff status, previous ipsilateral FP bypass, preoperative prediction of potential amputation level, concurrent proximal vascular reconstruction, and site of the distal anastomosis. We chose to validate the predictive model developed before applying it clinically. Data from 67 subsequent cases were presented to the computer without the known outcome, and the probability of 30-day patency was calculated. The model predicted 11 failures; there were actually eight thromboses in the 67 grafts. However, only three of the failures were predicted correctly, and eight cases of computer-anticipated thromboses were patent at 30 days. The high false positive rate makes the clinical application of the predictive model inappropriate. The success of FP bypass grafts appears to be related to factors that cannot be assessed preoperatively, such as technical problems during surgery. Even those which seem to have a poor runoff and other high-risk factors may succeed; thus an aggressive approach is justified in lower extremity reconstructions.
Blood Vessel Prosthesis↗
Clinical comparison of midazolam hydrochloride and midazolam maleate for anesthesia induction.
The current study was undertaken to determine whether the same doses (mg/kg) of 5 mg/ml of midazolam hydrochloride and 2.5 mg/ml of midazolam maleate are required for the induction of anesthesia. Midazolam hydrochloride and midazolam maleate were compared in a prospective double-blind fashion, in which both cardiopulmonary and sedative effects were measured in 12 patients who required repeated anesthesia for serial gynecologic radium insertions. The results showed no significant differences in clinical activity between midazolam maleate and the newer preparation, midazolam hydrochloride. Time of onset, recovery time, lack of venous irritation, and stability of cardiopulmonary variables when using the hydrochloride were essentially the same with the maleate.
Adult↗