123rc/medical_text huggingface dataset:
Hemodynamic determinants of subdiaphragmatic venous return during closed-chest CPR in a canine cardiac arrest model. OBJECTIVE: To assess the hemodynamic determinates of peripheral subdiaphragmatic venous-to-right-heart return during closed-chest CPR. MODEL: Seven anesthetized dogs subjected to electrically induced ventricular fibrillation for five minutes. INTERVENTIONS: Conventional closed-chest CPR and closed-chest CPR with continuous abdominal binding at a chest compression rate of 60 per minute, a compression-to-relaxation ratio of 50:50, and a ventilation-to-compression ratio of 1:5. METHODS: Solid-state catheters were positioned in the ascending aorta, right atrium (RA), and inferior vena cava (IVC). Cannulating electromagnetic flow probes were inserted into the IVC and a carotid artery. Analog-to-digital conversion was performed electronically. Five minutes after ventricular fibrillation was induced, interventions were performed in an alternating sequence. Systolic, diastolic, and mean pressures and flows were measured and compared. STATISTICAL METHODS: Two-tailed, unpaired t test applied to equal sample size, linear regression analysis, and multiple regression analysis. RESULTS: Abdominal binding during CPR significantly increased (P less than .05) all measured systolic and diastolic CPR intravascular pressures compared with CPR without abdominal binding but did not affect IVC-to-right-heart venous return. During conventional CPR without abdominal binding, venous return was dependent on the diastolic IVC pressure (r = .86, P = .014), mean IVC pressure (r = .80, P = .03), and carotid blood flow (r = .99, P = .001) but not on the IVC-to-RA pressure gradient. With abdominal binding, venous return was not correlated with any study hemodynamic variable, including the peripheral venous-to-RA pressure gradient. CONCLUSION: Venous return from the subdiaphragmatic venous bed during CPR is dependent on venous pressure, not on the peripheral venous-to-right-heart pressure gradient. Abdominal binding during CPR does not affect venous return. Venous return during CPR diastole is highly dependent on central venous capacitance (left heart outflow during CPR systole).
Achalasia in the elderly. Effects of aging on clinical presentation and outcome. Clinical and manometric data from 13 elderly subjects with idiopathic achalasia (mean age 79 +/- 2 years) were compared with findings from younger subjects with the same disease (n = 79) to see if aging altered the presentation and outcome of this motor disorder. Fewer elderly subjects complained of chest pain (27% vs 53%), and the pain was significantly less severe (P less than 0.01). Other presenting features (including sex, duration of symptoms, and presence and severity of dysphagia) did not differ between the groups. Across all patients, age weakly and inversely correlated with residual postdeglutitive lower esophageal sphincter; (LES) pressure (R = -0.34), and residual pressure was significantly lower in the older subjects (8.0 +/- 1.3 mm Hg vs. 11.9 +/- 0.8 mm Hg; P = 0.02). No differences in basal LES pressure or esophageal-body contraction amplitudes were present between the groups. Initial success with pneumatic dilation was similar in the two subject groups, but the number of older subjects available for analysis was too small to draw strong conclusions. These results indicate that aging decreases the elevation of LES residual pressure that occurs with achalasia. As elderly achalasia patients also present with less chest pain, the findings may be interrelated.
Blood transfusion and recurrence of colorectal cancer: the role of platelet derived growth factors. Efforts to explain the possible effects of blood transfusion on the recurrence of colorectal cancer have been based entirely on the immunosuppressive effects of blood transfusion. However, the relationship between solid tumour development and the immune system is inconclusive. We have investigated an alternative mechanism involving the potential role of growth factors in this phenomenon. Using a human fibroblast: [125I]deoxyuridine uptake mitogenesis assay, the relative amounts of growth factor in the plasma of stored blood were measured. There was a progressive increase in mitogenesis from day 0 (n = 6) to day 28 (n = 6; P less than 0.001, Mann-Whitney U test). The effect of growth factors on the development of liver and intraperitoneal metastases was studied in Hooded Lister rats. Following an intraportal injection of 10(5) MC28 tumour cells, the experimental group (n = 25) received 2 ml of syngeneic serum intravenously for 4 days. Likewise, colonic anastomoses were performed on omentectomized rats and the peritoneal cavity seeded with 10(3) cells. The experimental groups (n = 20) received either 2 ml serum intravenously repeatedly or 3 ml serum intraperitoneally (n = 19). There was no significant increase in liver metastases or peritoneal disease following intravenous infusion of serum but serum delivered intraperitoneally resulted in a significant increase in tumour from 22 per cent in the controls to 89 per cent in the study group (P less than 0.01). Growth factors released from platelets following blood loss into the peritoneal cavity may be important in enhancing local recurrence of colorectal cancer.
Power drills to fenestrate exposed bone to stimulate wound healing. Power drills can be used to stimulate the formation of granulation tissue over exposed cortical bone. These tools allow for the rapid fenestration and selective abrasion of large areas of exposed bone; fenestration and abrasion create the multiple bleeding points essential for the production of granulation tissue. The granulation tissue thus produced is allowed to grow out through the holes to cover bone. This procedure can be performed in an outpatient setting, usually without the need for either local or general anesthesia; it is particularly useful for patients considered to be poor risks for general anesthesia. Healing by granulation tissue is a somewhat slow process, but it has a high success rate, causes few complications, and produces very good cosmetic results. Two cases illustrate the method of fenestration of exposed cranial bone to stimulate granulation tissue. Specific instructions describe the needed care of exposed bone.
Recurrent thoracic outlet syndrome. Recurrent symptoms develop in 15% to 20% of patients undergoing either first rib resection or scalenectomy for thoracic outlet syndrome. Over the past 22 years 134 operations for recurrence were performed in 97 patients. Four operations were used: transaxillary first rib resection (26); supraclavicular first rib resection with neurolysis (15); scalenectomy with neurolysis (58); and brachial plexus neurolysis (35). Complications included temporary plexus injury (0.7%), temporary phrenic palsy (3.7%), and permanent phrenic palsy (1.4%). The combined primary success rate of all four operations for recurrence was 84% in the first 3 months. This fell to 59% at 1 to 2 years; 50% at 3 to 5 years; and 41% at 10 to 15 years. No significant difference was found in results between the four operations used for recurrence. When recurrence was caused by trauma the results of reoperations were better than when recurrence was spontaneous. The primary success rates of three initial operations for thoracic outlet syndrome were compared to their secondary success rates (improved after reoperation). By use of life-table methods, reoperation improved the 5- to 10-year success rate of transaxillary first rib resection from 69% to 86% and for scalenectomy from 69% to 84%. Reoperation is successful in most cases of recurrent thoracic outlet syndrome and better when recurrence is the result of a neck injury.
Angiographic progression to total coronary occlusion in hyperlipidemic patients after acute myocardial infarction. POSCH Group. The progression of coronary artery stenosis to total occlusion was assessed in 413 hyperlipidemic patients with a previous myocardial infarction. Coronary angiograms were recorded at baseline, 3 (n = 312), and 5 years (n = 248) after initial study and analyzed by 2 independent readers. There were 177 (43%) patients with 1-, 130 (31%) with 2-, and 61 (15%) with 3-vessel disease (greater than or equal to 50% diameter narrowing), whereas 45 (11%) did not have significant disease within a major coronary vessel at baseline. A new finding of total occlusion occurred in 4% (30 of 748) and 7% (40 of 605) of major coronary artery segments at 3 and 5 years, respectively. The risk of progression to total occlusion was higher if the initial stenosis was greater than 60% compared to lesions less than or equal to 60% both at 3 years (19 of 143 = 13% vs 11 of 605 = 2%; p less than 0.001) and 5 years (27 of 91 = 30% vs 13 of 514 = 3%; p less than 0.001). The frequency of occlusion was highest for the right coronary artery by 5 years (18 of 167 = 11% for right vs 8 of 225 = 4% for circumflex vs 14 of 213 = 7% for left anterior descending coronary arteries; p less than 0.02). Clinical and laboratory data revealed that myocardial infarction was associated with a new total occlusion in 23% of patients (7 of 30) at 3 years and in 64% (25 of 39) at 5 years.
Diastolic dysfunction in hypertrophic cardiomyopathy. Effect on active force generation during systole. We tested the hypothesis that intracellular Ca++ [( Ca++]i) overload underlies the diastolic dysfunction of patients with hypertrophic cardiomyopathy. Myocardial tissue was obtained at the time of surgery or transplantation from patients with hypertrophic cardiomyopathy and was compared with control myocardium obtained from patients without heart disease. The isometric contractions and electrophysiologic properties of all myocardial specimens were recorded by standard techniques and [Ca++]i was measured with the bioluminescent calcium indicator aequorin. In contrast to the controls, action potentials, Ca++ transients, and isometric contraction and relaxation were markedly prolonged in the hypertrophic myocardium, and the Ca++ transients consisted of two distinct components. At 38 degrees C and 1 Hz pacing frequency, a state of relative Ca++ overload appeared develop, which produced a rise in end-diastolic [Ca++]i, incomplete relaxation, and fusion of twitches with a resultant decrease in active tension development. We also found that drugs with increase [Ca++]i, such as digitalis, exacerbated these abnormalities, whereas drugs that lower [Ca++]i, such as verapamil, or agents that increase cyclic AMP, such as forskolin, prevented them. These results may explain why patients with hypertrophic cardiomyopathy tolerate tachycardia poorly, and may have important implications with regard to the pharmacologic treatment of patients with hypertrophic cardiomyopathy.
Intrahepatic arterioportal fistula after blunt hepatic trauma: case reports. Intrahepatic arterioportal fistula (APF) was found in five out of 65 consecutive patients following blunt hepatic trauma. In four patients the fistula was located peripherally and the blood flow was small. These fistulas closed spontaneously within 3 months. However, a centrally located fistula with early visualization of the trunk of the portal vein persisted in one patient and necessitated transcatheter embolization. The APF in this patient caused portal dilatation which was detectable by CT scan. We conclude that spontaneous closure can be expected when an APF is located peripherally and the shunt flow is small, while centrally located APF with large flow require active treatment, preferably by transcatheter embolization. An APF detectable by CT scan suggests the need of intervention.
Decreasing the risk of human immunodeficiency virus or hepatitis B virus infection during endoscopic surgery. The risk of transmission of human immunodeficiency virus and hepatitis B virus infection is small but finite. Urological surgeons are exposed through needle punctures in open surgery and splashes during endoscopic surgery. Safety glasses are difficult to use during endoscopic surgery and they do not offer complete protection. The Steri-Shield, a facial shield designed to be fixed to the endoscope, is described.
Morbidity, mortality, and quality of life for patients treated with levothyroxine In a population study of 1462 middle-aged women initiated in 1968 and 1969 we identified 29 women treated with levothyroxine from 1 to 28 years. In a 12-year follow-up in 1980 and 1981 we investigated the subjects for end-point myocardial infarction, diabetes mellitus, stroke, cancer, and death (the status of 99.7% of the initial participants was established). The women treated with levothyroxine showed no increase in morbidity or mortality. Of the 24 women still receiving levothyroxine in 1980 and 1981, 22 had serum thyrotropin and triiodothyronine concentrations with-in reference limits. These individuals were compared with the 968 women from the population study having no history of thyroid disease, and appeared identical as to laboratory and clinical data, with the exception of a slightly higher body mass, taller stature, and lower serum cholesterol concentration. The treated group did not differ in a life quality estimate based on 19 questions regarding life satisfaction and sensory function. We conclude that the levothyroxine-treated woman suffers no side effects from her life-long therapy.
Ischemic heart disease and platelet aggregation. The Caerphilly Collaborative Heart Disease Study. The Caerphilly Collaborative Heart Disease Study is based on a large cohort of men (2,398) aged 49-66 years at the time of study. Platelet aggregation induced by collagen, thrombin, and ADP was measured in fasting blood samples and was related to prevalent angina, past myocardial infarction, and electrocardiographic evidence of ischemic heart disease. A number of subjects had taken aspirin, other nonsteroidal anti-inflammatory drugs, or other drugs affecting platelet aggregation 7 days before blood sample collection; after the exclusion of these subjects, data were available for 1,811 men. No relations were demonstrated with angina, but significant relations were shown between past myocardial infarctions and electrocardiographic evidence of ischemia and ADP-induced aggregation (both primary and secondary) and between electrocardiographic evidence of ischemia and thrombin-induced aggregation. The strongest relation indicated more than a twofold increase in the odds of a past myocardial infarction in subjects of the highest fifth of ADP-induced primary platelet aggregation compared with the lowest fifth. No significant relations were detected with collagen-induced aggregation. Accounting for a number of possible confounding factors had a relatively small impact on the relations between platelet aggregation and ischemic heart disease. Other evidence, including the well-established effect of aspirin on reducing the incidence of ischemic heart disease, indicates that the relations we describe are unlikely to be simply an effect of IHD on platelets.
Etiology and mechanisms of acute infectious diarrhea in infants in the United States. Infectious diarrhea, caused by a wide variety of viral, bacterial and parasitic pathogens, is a common reason for morbidity and hospitalization for children in the United States. Overall, rotavirus is the most common cause of acute diarrheal disease in infants. Salmonella, Shigella, and Campylobacter are the most frequently isolated bacterial pathogens, and Giardia and Cryptosporidium are the parasites that most commonly produce acute infectious diarrhea. The mechanisms by which these enteropathogens cause diarrhea are highly variable, and include crypt cell proliferation, cellular invasion, elaboration of enterotoxins or cytotoxins, and enteroadhesion. In infants the incidence of diarrheal disease is higher and the severity of the illness is greater than in older children and adults. An increased rate of exposure to enteropathogens, as a result of fecal-oral contamination, may explain some of the increased incidence of diarrhea in infants. However, age-specific differences in host defense mechanisms may also account for the increased susceptibility to and severity of certain enteric infections in infants.
Therapeutic considerations in the elderly hypertensive. The role of calcium channel blockers. Hypertension is an extremely common problem in the elderly. The optimum antihypertensive agent to use in this population is not certain. In this paper, the factors influencing the choice of antihypertensive therapy are reviewed. They include efficacy, safety, comorbidity, utility in special populations, drug interaction, dosage schedule, cost, the mechanisms of action of the drug, and the pathophysiology of the patient's hypertension. Calcium channel blockers are effective and safe in the elderly. They improve other conditions frequently seen in that population and, with the exception of cardiac conduction abnormalities associated with some calcium channel blockers, do not adversely affect other comorbid diseases. They work well together with other antihypertensives and as vasodilators, they may be specifically appropriate in elderly hypertensives, whose hypertension is associated with reduced cardiac output and increased peripheral vascular resistance. Once- and twice-a-day preparations are available to foster compliance, but calcium channel blockers are expensive.
Antiepileptic drug intoxication: factors and their significance. A retrospective chart review (1979-1985) was performed to identify probable causes of intoxication with antiepileptic drugs (AEDs). We identified 141 patients meeting clinical and laboratory criteria for intoxication and 17 with clinical signs but with serum concentrations within the therapeutic range. The majority were epileptic patients; almost half were treated with monotherapy, most with phenytoin (PHT). The causes of intoxication in the epileptic patients were iatrogenic (41%), inappropriate dose self-adjustment (34%), suicide attempt (18%), inappropriate caretaker dose adjustment (9%), accidental ingestion (8%), unrecognized drug interaction (6%), and association with intercurrent illness (2%). Twenty-two patients had more than one probable cause of intoxication. In nonepileptic patients the causes were suicide attempt (50%), accidental ingestion (27%), and iatrogenic (23%). Most patients had signs of ocularmotor and vestibulocerebellar dysfunction. Rarely described manifestations of intoxication, such as seizures or choreoathethosis, were observed in a few patients. The average hospital stay was 6.9 days; there was no mortality, and all patients recovered fully. We conclude that AED intoxication is a major but preventable cause of morbidity and that suicide attempts are an important and underrecognized contributor in both epileptic and non-epileptic patients.
Modified technique of Pringle's maneuver in resection of the liver. Crushing of the hepatic parenchyma with hepatic clamps to minimize blood loss during resection of the liver leads to mechanical damage of hepatocytes. Pringle's maneuver may precipitate liver failure by hepatic warm ischemia as well. Therefore, we controlled bleeding from the surface of the resection by using light compression on the hepatic parenchyma with a band while applying a hepatic arterial clamp at the hepatic hilus. This vascular control method can be done because the portal pressure is about one-tenth of the hepatic artery pressure and provides an efficient and harmless transection of the liver.
Effects of pressure and volume of the receiving chamber on the spatial distribution of regurgitant jets as imaged by color Doppler flow mapping. An in vitro study. Regurgitant jet dimensions imaged by color Doppler flow mapping have been used to evaluate the severity of valvular insufficiency in clinical studies. To study the effect of pressure and volume within the receiving chamber on the magnitude of spatial distribution of regurgitant jets assessed by color Doppler techniques, we designed a simple constant-flow model in which a jet was driven through a known orifice (1.5 mm2) into a compliant receiving chamber by a steady-flow pump. A distal tube at the outflow closed the system and maintained the volume of the chamber constant during pump operation. We varied flow rate from 60 to 270 ml/min into elastic balloons with different static compliances of 1, 2, 4.5, and 9 ml/mm Hg (pressures of 57, 28, 18, and 8 mm Hg, respectively); the balloons served as receiving chambers at the constant volume of 150 ml. We also evaluated the effect of different volumes of a receiving chamber (110, 130, and 150 ml and pressures of 5, 15, and 24 mm Hg) with a static compliance of 2 ml/mm Hg over the same range of flow rates. For each of the different balloons, jet area correlated linearly with the jet velocity across the orifice (r = 0.98, 0.99, 0.98, and 0.97) and also with flow rate (r = 0.97, 0.99, 0.98, and 0.99). At the same flow rate and volume of receiving chamber, however, the jet area imaged by color Doppler decreased as the pressure in the receiving chamber increased, although receiving-chamber volume was constant.
A detachable balloon procedure for a traumatic internal carotid-internal jugular fistula: report of a case A case of a traumatic fistula between the internal carotid artery and the internal jugular vein is reported. The fistula was treated by detachable balloon occlusion and clipping of the internal carotid artery.
Endoscopic laser arytenoidectomy revisited. Arytenoidectomy is currently the most reliable method of treating patients with bilateral vocal cord paralysis. Although both endoscopic and external approaches have been described, the endoscopic laser technique is more desirable because it requires no incision and allows for the immediate assessment of airway size. Eleven patients with bilateral vocal cord paralysis treated by endoscopic laser arytenoidectomy were presented in 1984. At that time, 10 of the 11 patients had been successfully decannulated. Follow-up on that group of patients revealed that 7 of the 10 successfully treated patients remain decannulated with a good airway, although 2 of these patients required a revision procedure to excise a granuloma. One patient failed at 15 months and has failed two subsequent revision operations, and 2 patients have been lost to follow-up. Since 1984, 17 additional patients with bilateral vocal cord paralysis have been treated by the authors using the same endoscopic laser arytenoidectomy technique; all have been successfully managed, with a minimum follow-up of 3 years. The technique of this operation will be reviewed. This study demonstrates the clinical usefulness of endoscopic laser arytenoidectomy in the treatment of bilateral vocal cord paralysis.
Quantification of biomedical findings of chronic pain patients: development of an index of pathology. Difficulties in assessing and quantifying the biomedical signs and symptoms that may be related to patients' reports of pain are well recognized. Although there appears to be some consensus among physicians as to the potential utility of examination and diagnostic tests frequently used to evaluate chronic pain patients, little attention has been paid to the reliability of interpreting the results of these procedures. Moreover, the integration of biomedical findings to form a general index of pathology associated with chronic pain has been a difficult problem to solve because not all biomedical procedures used to evaluate pain patients are necessarily relevant or indicated for a specific patient. Two studies are presented that were designed to evaluate the reliability of 23 biomedical procedures commonly used to evaluate chronic pain patients and to determine if findings on these procedures can effectively be combined to form a reliable index of physical pathology. The results of study 1 suggest that 17 of the 23 procedures can be applied in clinical setting with acceptable levels of reliability. Study 2 provides evidence that an innovative weighted scoring approach, based on current medical consensus, can be used to produce a reliable, general index of pathology that is independent of the number of procedures used to evaluate patients. The utility of this quantification approach to biomedical findings for clinical and research purposes is discussed.