Responsibilities and rights.
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Ethics, Medical↗
Biomedical subjects
D Silver
Publications and source records attributed to D Silver.
An overview of venous thromboembolism prophylaxis.
This symposium reviewed the risk factors and problems associated with venous thromboembolism in surgical patients, especially those patients having total hip replacement. The importance of venous thromboembolism prophylaxis was emphasized by a theoretical analysis indicating that venous thromboembolism in patients having hip replacement not only saves lives but is also effective. A discussion of the pharmacology of low-molecular-weight heparin (LMWH) included a review of its role, clinically and experimentally, in venous thromboembolism prophylaxis. Three of the discussants presented their favorable experiences with LMWH in reducing the incidence of venous thromboembolism in patients having hip replacement. It can be concluded that LMWH does reduce the incidence of venous thromboembolism in patients having hip replacement without causing an increase in blood loss. If its effectiveness and safety remain substantiated, LMWH may soon become the preferred agent for venous thromboembolism prophylaxis.
Humans↗
Mood variability in adolescents: a study of depressed, nondepressed and comorbid patients.
In a study to examine the variability of mood in psychiatrically disturbed adolescents, 30 inpatients aged 13-17 reported on current depressive symptoms three times a day for seven consecutive days, using a set of visual analog scales (the Adolescent Mood Scale: AMS) to record DSM-IIIR and other depressive symptoms. Ten of the patients had no depressive diagnosis; 11 had both a depressive and an 'externalizing' diagnosis (mainly conduct disorders and substance abuse disorders), and nine had depressive diagnoses but no externalizing disorder. Variability was defined in terms of (1) range of AMS scores; (2) amount of change from one test point to the next; (3) rhythmicity, measured by the autocorrelation function across 21 test points. All three groups had high levels of depressive symptoms throughout the week. On all measures of severity of depression, the depressed girls were more depressed than the depressed boys, irrespective of comorbidity. Measures of variability, however, showed no effect of sex, but comorbid patients were more likely to have a wide range of mood scores, and reported a 45% greater amount of mood change. Only five subjects had a significant lag1 autocorrelation function, and there was no indication of diurnal rhythmicity. Implications for research and diagnosis are discussed.
Adolescent↗
Recovery of neuromuscular function during reperfusion of the ischemic extremity: effect of mannitol and superoxide dismutase.
The ability of mannitol and superoxide dismutase (SOD) to improve the recovery of peripheral nerve and skeletal muscle function and to influence metabolism during reperfusion after 4 hours of complete ischemia was investigated in an autoperfused canine hind-limb model. Study groups included control subjects (n = 7), subjects given 5000 units/kg of SOD intra-arterial bolus immediately before reperfusion and 10,000 units/kg infusion during first hour of reperfusion (n = 7), and subjects given 150 mg/kg isosmolar mannitol intra-arterial bolus before reperfusion and 1 gm/kg intravenous infusion during the first hour of reperfusion. Function was evaluated by determining isometric twitch and tetanic contractile force of paw dorsiflexion by stimulating the peroneal nerve or the anterior tibial muscle. Metabolic responses (oxygen consumption and lactate clearance) and blood flow were not influenced by either treatment protocol. However, mannitol significantly reduced muscle damage and significantly improved neuromuscular contractile function compared to control and SOD treatment regimens.
Analysis of Variance↗
Complete external iliac artery disruption after percutaneous aortic valvuloplasty in two young children: successful repair with hypogastric artery transposition.
The majority of vascular injuries in young children are iatrogenic. This is a report of two complete external iliac artery disruptions occurring during percutaneous transfemoral balloon aortic valvuloplasty in a 2-year-old and a 5-year-old child. The damaged external iliac artery was bypassed by extensively mobilizing the hypogastric surgery and rotating it upward to anastomose it to the proximal common femoral artery. Normal limb pulses, function, and growth were noted in follow-up.
Anastomosis, Surgical↗
Children's understanding of private keys in referential communication.
A private key is a referential utterance used to inform selectively. The ambiguity of the utterance conceals meaning from nonselected audience members. The purpose of this study was to examine three aspects of children's understanding of the use of private keys. Experiment 1 concerned children's sensitivity to information in the context of utterance (i.e., the common ground). Experiment 2 examined appreciation of audience design and the speaker's intent. Experiments 3, 4, and 5 explored some reasons for children's problems in understanding private keys. The results show that even first graders are sensitive to common ground information and the speaker's intent. However, audience design is troublesome even for second graders in some situations, probably because they fail to assess the knowledge of the audience members. Private keys are important theoretically because they represent an aspect of referential communication involving the uses of ambiguous utterances that have been ignored by developmental researchers.
Attention↗
The relation between item identification difficulty and elaborative conceptual processing for children and adults.
The four experiments concerned the relation between the difficulty of item identification processes, elaborative conceptual processing, and developmental differences in cued recall. Elaborative conceptual processing was manipulated by asking related ("How many are related?"), category ("How many are vehicles?"), and analytic ("How many usually carry freight?") orienting questions about four-word stimuli in which the words were categorically related (Bus-Airplane-Car-Train). The measures of elaborative processing were the speed and accuracy of question answers. Cued recall for the targets (Train) was assessed for one-word (Bus) or two-word (Bus-Airplane) cues, which were varied to determine if elaborative processing affected cue discriminability or constructability, or both. The difficulty of item identification was varied in several ways. In Experiment 1, the graphemic information was degraded in the acquisition stimuli, or the retrieval cues, or the stimulus words were intact. In Experiments 2 and 3, acquisition presentation time was varied and the stimuli were read by the experimenter or the subject. Experiment 4 featured pictures to determine generalizability. The results showed that elaborative conceptual processing facilitates recall. Most important, item identification processes limit elaborative conceptual processing for both words and pictures, and more for children than for college students.
Adolescent↗
Hypercoagulable states.
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Blood Coagulation Disorders↗
Heparin-induced thrombocytopenia in patients who undergo open heart surgery.
To determine whether heparin-dependent antiplatelet antibodies (HAAb) have an effect on morbidity and/or mortality rates, we reviewed the cases of 3438 patients who underwent open heart surgery from 1981 to 1989. Forty-six patients (1.3%) had HAAb. The patients were divided into two groups: those patients who were known to have HAAb before surgery (group I) and those patients who were diagnosed with HAAb after surgery (group II). Group I patients (n = 5) were pretreated with platelet-inhibiting drugs before reexposure to heparin during cardiopulmonary bypass and were maintained with strict abstinence from heparin afterward. Their lowest observed platelet counts ranged from 42,000/mm3 to 89,000/mm3 (median, 63,00/mm3). Thromboembolic complications did not occur, and all patients survived. Group II patients (n = 41) who were diagnosed to have HAAb after surgery had not been pretreated with platelet-inhibiting drugs before surgery. Lowest platelet counts ranged from 11,000/mm3 to 128,000/mm3 (median, 42,000/mm3). Bleeding complications occurred in 21 patients (51%), and thromboembolic complications occurred in 13 patients (32%). Hospital mortality in group II patients was 37%. Late recognition of HAAb was associated with an increase in morbidity and mortality rates. Thromboembolic complications of HAAb, which had been diagnosed before surgery, were eliminated, and bleeding was reduced by pretreatment with platelet-inhibiting drugs and strict abstinence from heparin after surgery.
Acute Kidney Injury↗
Concept availability in the causal inferences of children and adults.
What supplies the concepts in causal inferences in story comprehension? This question was examined in 5 experiments. Elementary school children and college students listened to stories containing a "premise" sentence describing a character's intent in initiating a series of actions, followed by an unexpected "outcome." After each story, the subjects were asked inference questions about the reason for the outcome (Experiments 1-4) or asked to explain the outcome (Experiment 5). In the various experiments, the availability of object concepts for an inference was manipulated by providing 0 or 2 clues preceding the outcome, additional filler information that diluted the clue information, a mention of an object in the premise or no mention, and an object title for each story or no title. The results suggested that the availability of an object concept in sentences prior to the outcome was a critical determinant of whether an object inference occurred, especially for children. Given availability, the thematic prominence of the object influences whether the object will be used in an inference.
Adolescent↗
Reexposure to heparin of patients with heparin-associated antibodies.
Four patients with heparin-associated antiplatelet antibodies who were not receiving platelet function-inhibiting agents received heparin during surgery, angiography, or hemodialysis. Three of the four patients had complications that were attributed to heparin-induced platelet aggregation. The complications included a superficial femoral artery thrombosis, a thrombotic stroke after a carotid endarterectomy, and recurring thrombosis of a graft inserted for dialysis. Nine patients received aspirin (325 mg b.i.d.) or dipyridamole (Persantine) (200 to 300 mg daily) before reexposure to 5000 to 12,000 units of heparin during 11 vascular procedures. The procedures included two carotid endarterectomies, three aortofemoral bypasses, one femoropopliteal bypass, two femorotibial in situ saphenous vein bypasses, one iliofemoral thrombectomy, one bilateral iliac artery angioplasty, and one axillobifemoral bypass. Platelet counts averaged 173,000/mm3 before heparin reexposure, fell to an average of 86,000/mm3 within 24 hours of heparin reexposure, and returned to normal within 48 hours after the reexposure. None of these patients had a thromboembolic or hemorrhagic complication. Patients with heparin-associated antiplatelet antibodies are at risk for developing thrombocytopenia and thromboembolic complications on reexposure to heparin. The platelet function-inhibiting agents, aspirin and Persantine, protect the patients from the thromboembolic complications but not the thrombocytopenia associated with limited heparin reexposure.
Angiography↗
How black and Latino community organizations respond to the AIDS epidemic: a case study in one New York City neighborhood.
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Acquired Immunodeficiency Syndrome↗
Transaxillary or supraclavicular decompression for the thoracic outlet syndrome. A comparison of the risks and benefits.
The difficult exposure with the transaxillary resection of the first rib (TAR) prompted an analysis of the TAR versus the supraclavicular approach (SCR) for decompressing the thoracic outlet in patients with thoracic outlet syndrome (TOS). Thirty-seven patients underwent 30 TAR and 15 underwent SCR for TOS. The operating time was similar for the two groups. Mean blood loss was 61 cc for the SCR group and 218 cc for the TAR group. There was one complication in the SCR group, a urinary tract infection, whereas the TAR group had 21 complications including pneumothorax (13), laceration of subclavian vessel (3), winged scapula (3), pleural effusion (1), and wound infection (1). Postoperative hospitalization averaged 3 and 5 days, respectively, for the SCR and TAR patients. All SCR patients and all but one TAR patient were improved or asymptomatic immediately postoperatively. Ninety-three per cent and 81 per cent, respectively, of SCR and TAR patients were improved at 2 months, whereas 100 per cent and 83 per cent, respectively, remained improved at a mean follow-up of 3 years. The significantly fewer complications, decreased blood loss and shorter postoperative hospitalization, noted in the SCR patients supports this approach as the preferred form of management for TOS.
Adult↗
Thrombocytopenia associated with heparin-coated catheters in patients with heparin-associated antiplatelet antibodies.
Thrombocytopenia was associated with the presence of heparin-coated pulmonary artery catheters in 12 patients with heparin-associated antiplatelet antibodies. The thrombocytopenia persisted so long as the heparin-coated catheters were in place, even when all other sources of heparin were discontinued. The high morbidity and mortality associated with heparin-induced thrombocytopenia mandates that heparin administration cease and that all heparin-coated catheters be removed from patients with heparin-associated antiplatelet antibodies.
Aged↗
Surgical management of refractory venous stasis ulceration.
A 15-year experience with 27 patients, 20 to 75 years of age, with refractory venous stasis ulcers is presented. All patients had been managed with support hose, elevation, elastic wraps, Unna's paste boots, and graduated compression stockings. Because of multiple recurrences of their ulcers, the patients were offered surgical treatment to reduce the venous hypertension in the areas of ulceration. The 27 patients had 32 modified Linton procedures. Five had bilateral procedures. At the time of operation, 18 limbs had medial malleolar ulcers, five had bimalleolar ulcers, four had lateral ulcers, three had posterior ulcers, and two patients were free of ulcer. Medial incisions were used in 20 limbs, lateral incisions in six, medial and lateral incisions in three, and midposterior incisions in three. Split-thickness skin grafts were placed on six limbs the day of surgery and on 22 limbs 4 to 7 days later. Postoperative complications included deep venous thrombosis in two, partial flap necrosis in three, and cellulitis of the lower leg in three patients. Follow-up has ranged from 6 months to 10 years. During the most recent clinic visits, 21 limbs were completely healed, whereas six limbs had a recurrence of the ulcer. Five patients have been lost to follow-up. The good long-term results in 78% of the cases indicate that patients with recurrent venous stasis ulcers may receive lasting benefit from modified Linton procedures.
Adult↗
Heparin-coated catheters and heparin-induced thrombocytopenia.
Ten patients with heparin-coated pulmonary artery catheters had heparin-induced thrombocytopenia, which persisted after all other sources of heparin were discontinued. The thrombocytopenia occurred in approximately 0.4% of the patients receiving heparin-coated catheters and remitted when the catheters were removed. The platelet counts averaged 59,000/mm3 at the time of the diagnosis and recovered to an average of 143,000/mm3 by 3 days (range 2 to 4 days) after removal of the heparin-coated catheters. One patient required a second catheter 31 days after the first catheter had been removed. When the second heparin-coated catheter was inserted, the platelet count decreased from 307,000/mm3 to 102,000/mm3 in 4 days. Segments of heparin-coated pulmonary artery catheters were placed in platelet-rich plasma and incubated with serum from patients with known heparin-associated antiplatelet antibodies or with serum from volunteers with no exposure to heparin. The heparin-coated catheters induced platelet aggregation in all samples containing serum from patients with heparin-induced thrombocytopenia. However, platelet aggregation did not occur when the catheters were incubated with the serum of the volunteers. Non-heparin-coated catheters failed to produce platelet aggregation when incubated with either sera. The high mortality and morbidity rates associated with heparin-induced thrombocytopenia mandate that afflicted patients receive no more heparin, at least until the heparin-associated antiplatelet antibodies are no longer detectable. Patients with heparin-coated catheters who have thrombocytopenia should be tested for the presence of heparin-associated antiplatelet antibodies. If heparin-induced thrombocytopenia is confirmed, the catheters must be removed if the thrombocytopenia is to be reversed and complication avoided.
Aged↗
Lower extremity edema from bladder compression of the iliac veins.
Two elderly men were referred to our vascular clinic for the management of bilateral lower extremity edema of 2 to 3 months' duration. Their evaluation included phlebograms, which demonstrated external compression of their iliac veins. CT scans of the pelvis suggested that large bladders caused the compression. Each patient had mild symptoms of prostatism. Transurethral resection of the prostate was recommended to and accepted by each patient. Decompression of the bladder was accompanied by complete relief of the lower extremity venostasis in both patients. Review of the literature yielded only eight similar cases of this unusual cause of lower extremity edema.
Aged↗
Aneurysms and pseudoaneurysms of the superficial temporal artery caused by trauma.
Superficial temporal artery (STA) aneurysms as a result of trauma represent less than 1% of reported aneurysms. During the past 200 years only the type of trauma and the preferred treatment have significantly changed. Patients are generally young men with a recent history of blunt head trauma. They may complain of a mass, headache, or other vague symptoms. Neurologic defects are rare; however, if a neurologic deficit exists, the physician should consider either arteriography or a head CT scan to search for intracranial pathologic conditions. In most cases the diagnosis may be made by obtaining a complete history and physical examination. The treatment of choice is ligation and resection, which may be accomplished with the patient under local or general anesthesia. In rare instances, arteriography with selective embolization may be useful when the traumatic aneurysm is complicated by severe facial trauma. Three cases of STA aneurysms are presented. The history, pathophysiology, origin, presentation, diagnosis, differential diagnosis, and treatment of STA aneurysms are reviewed.
Adolescent↗