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Sequential pulse defibrillation in man: comparison of thresholds in normal subjects and those with cardiac disease. 人序贯脉冲除颤:正常人和心脏病患者阈值的比较
Medical instrumentation Pub Date : 1987-06-01
D L Jones, G J Klein, G M Guiraudon, A D Sharma, M J Kallok, W A Tacker, J D Bourland
{"title":"Sequential pulse defibrillation in man: comparison of thresholds in normal subjects and those with cardiac disease.","authors":"D L Jones,&nbsp;G J Klein,&nbsp;G M Guiraudon,&nbsp;A D Sharma,&nbsp;M J Kallok,&nbsp;W A Tacker,&nbsp;J D Bourland","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>We compared the parameters describing the defibrillation threshold in patients with normal hearts and in patients with ischemic heart disease, using a special electrode system and sequential pulses of current. Twenty-eight patients consented to the study (mean age: 36.6 +/- 10.1 years; mean mass: 80.7 +/- 13.8 kg). Twenty-one patients underwent surgery for Wolff-Parkinson-White syndrome (relatively normal hearts). Six patients had a history of previous myocardial infarction and aneurysm or coronary artery disease; and one patient had been resuscitated from an episode of sudden death, without evidence of consequent myocardial damage. For 26 patients, defibrillation thresholds were determined intraoperatively by passing sequential pulses through a catheter electrode and epicardial mesh electrode. For 2 patients defibrillation thresholds were determined during electrophysiologic study, after ventricular fibrillation was induced by programmed stimulation, by passing sequential pulses through a catheter and skin-patch electrode. Parameters for sequential pulse defibrillation thresholds between the two groups did not differ appreciably. Total energy for patients with normal hearts averaged 9.9 +/- 6.3 J compared to 8.9 +/- 4.6 J for patients with cardiac disease. No patient with cardiac disease had defibrillation parameters that exceeded the range of the normal patients. These results suggest that the presence of cardiac disease may not significantly alter the parameters necessary for successful defibrillation when using sequential pulses for delivery of energy.</p>","PeriodicalId":76133,"journal":{"name":"Medical instrumentation","volume":"21 3","pages":"166-9"},"PeriodicalIF":0.0,"publicationDate":"1987-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14735539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Lead configurations in esophageal electrocardiography. 食道心电图中的铅位。
Medical instrumentation Pub Date : 1987-06-01
H Jadvar, J M Jenkins
{"title":"Lead configurations in esophageal electrocardiography.","authors":"H Jadvar,&nbsp;J M Jenkins","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>There are many clinical situations that present the need for special purpose electrocardiography using standard equipment. These include monitoring cardiac activity from temporary myocardial leads implanted following cardiac surgery, detecting signals from intracardiac catheter leads, and noninvasive atrial recording from the esophagus. It is often difficult to connect nonstandard leads and access the individual amplifiers. In this article, we present the case for an esophageal electrode such as the Pill Electrode (Arzco Medical Electronics, Inc., Chicago, IL). We describe several configurations for connecting this electrode to electrocardiographs and comment on the merits and shortcomings of each method.</p>","PeriodicalId":76133,"journal":{"name":"Medical instrumentation","volume":"21 3","pages":"158-65"},"PeriodicalIF":0.0,"publicationDate":"1987-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14735538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
An aerosol generator system for inhalation delivery of pharmacologic agents. 一种用于吸入输送药理学制剂的气溶胶发生器系统。
Medical instrumentation Pub Date : 1987-06-01
A A Strong, M J Hazucha, D A Lundgren, E R Cerini
{"title":"An aerosol generator system for inhalation delivery of pharmacologic agents.","authors":"A A Strong,&nbsp;M J Hazucha,&nbsp;D A Lundgren,&nbsp;E R Cerini","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Most commercially available aerosol generators widely used in medical applications produce aerosols characterized by a large mass median diameter in the 4-8 micron range and the particle size in the 0.1-10.0 microns range. The desirable size of therapeutic and diagnostic aerosols, however, is about 2-4 microns mass median diameter, and less than 2.0 geometric standard deviation; this size increases the reproducibility of inhalation tests and enhances drug efficacy. We combined the commercially available DeVilbiss Model 65 nebulizer with a dilution/mixing chamber developed in our laboratory. The characteristics of this aerosol generator system were examined over a range of operating conditions and concentrations of solutions of three bronchoconstrictive agents--histamine, carbachol, and methacholine. The aerosol generator system produced a polydispersed aerosol with a mass median diameter range of 1.7-2.4 microns and geometric standard deviation of 1.5. The reliable and reproducible operation of the aerosol generator system greatly increases the power of bronchial challenge tests with bronchoconstrictive drugs.</p>","PeriodicalId":76133,"journal":{"name":"Medical instrumentation","volume":"21 3","pages":"189-94"},"PeriodicalIF":0.0,"publicationDate":"1987-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14429932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Continuous-wave Doppler for the noninvasive evaluation of aortic blood velocity and rate of change of velocity: evaluation in dogs. 连续波多普勒无创评价主动脉血流速度和速度变化率:犬的评价。
Medical instrumentation Pub Date : 1987-06-01
P D Stein, H N Sabbah, D E Albert, J E Snyder
{"title":"Continuous-wave Doppler for the noninvasive evaluation of aortic blood velocity and rate of change of velocity: evaluation in dogs.","authors":"P D Stein,&nbsp;H N Sabbah,&nbsp;D E Albert,&nbsp;J E Snyder","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>A new continuous-wave Doppler device is described, which has the capability of measuring peak aortic blood velocity and acceleration noninvasively in the ascending aorta of patients. To test the accuracy of the device, blood velocity and acceleration in the ascending aorta were compared with measurements obtained using an electromagnetic flowmeter in 16 open-chest anesthetized dogs. The Doppler probe was hand held directly on the aorta. Aortic flow was measured with a cuff electromagnetic flow transducer placed at the root of the aorta. Isoproterenol and propranolol, sometimes in combination with lidocaine, were administered intravenously to augment or reduce left ventricular contractile performance. Values of peak velocity, measured with the Doppler, corresponded closely to values measured with the electromagnetic flowmeter (r = 0.95). Values of peak acceleration also corresponded closely with the electromagnetic flow measurements (r = 0.96). The results indicate that valid measurements of blood acceleration in the ascending aorta, as well as blood velocity, can be obtained with continuous-wave Doppler.</p>","PeriodicalId":76133,"journal":{"name":"Medical instrumentation","volume":"21 3","pages":"177-82"},"PeriodicalIF":0.0,"publicationDate":"1987-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14090816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A pocket microprocessor-controlled ECG with LCD display: description, evaluation, and perspectives. 一个袖珍微处理器控制的心电图与液晶显示:描述,评估,和观点。
Medical instrumentation Pub Date : 1987-06-01
D Adler, Y Mahler
{"title":"A pocket microprocessor-controlled ECG with LCD display: description, evaluation, and perspectives.","authors":"D Adler,&nbsp;Y Mahler","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":76133,"journal":{"name":"Medical instrumentation","volume":"21 3","pages":"195-8"},"PeriodicalIF":0.0,"publicationDate":"1987-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14429933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The cardiac ventricular defibrillation threshold: inherent limitations in its application and interpretation. 心室除颤阈值:其应用和解释的固有局限性。
Medical instrumentation Pub Date : 1987-06-01
W C McDaniel, J C Schuder
{"title":"The cardiac ventricular defibrillation threshold: inherent limitations in its application and interpretation.","authors":"W C McDaniel,&nbsp;J C Schuder","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>A quantity termed the \"threshold\" has been used to describe the results of electrical ventricular defibrillation studies, with the implication of a clear distinction between ineffective and effective shock intensities. Although several definitions of the threshold have been suggested, and various methods have been used to quantify it, no comparison of the accuracies of the various methods could be found in the literature. This article, after presenting a method of applying basic probability theory to an assumed distribution relating probability of successful defibrillation to current amplitude, uses the method to examine several popular algorithms for defibrillation-threshold determination. The results show that where a sharp transition exists from ineffective to effective current amplitudes, most algorithms yield fairly good results. Where that transition is gradual (as it appears to be in all of the published reports examined), the algorithms are shown to be inadequate.</p>","PeriodicalId":76133,"journal":{"name":"Medical instrumentation","volume":"21 3","pages":"170-6"},"PeriodicalIF":0.0,"publicationDate":"1987-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14735540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Rationale for coronary venous bypass grafting in patients with diffuse coronary artery disease. 弥漫性冠状动脉疾病患者冠状静脉旁路移植术的基本原理。
Medical instrumentation Pub Date : 1987-06-01
M S Hochberg
{"title":"Rationale for coronary venous bypass grafting in patients with diffuse coronary artery disease.","authors":"M S Hochberg","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":76133,"journal":{"name":"Medical instrumentation","volume":"21 3","pages":"200-3"},"PeriodicalIF":0.0,"publicationDate":"1987-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14619821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Adapting personal computers for use by high-level quadriplegics. 调整个人电脑以供高级四肢瘫痪者使用。
Medical instrumentation Pub Date : 1987-04-01
M J Kilgallon, D P Roberts, S Miller
{"title":"Adapting personal computers for use by high-level quadriplegics.","authors":"M J Kilgallon,&nbsp;D P Roberts,&nbsp;S Miller","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>A communication instrument has been developed for use by a quadriplegic person who is limited solely to eye motion as a control input. The instrument uses an infrared-emitting diode/phototransistor sensor mounted on the frame of a pair of eyeglasses to transform deliberate lateral eye motion into a contact-closure output form. A software program has also been developed for use with this instrument to display letters of the alphabet in a series of six lines. The lines are slowly scrolled until the desired line is reached, then stopped by a lateral eye motion. The scrolling then continues for each character in that line until the desired character is reached. Again, lateral eye movement causes the scrolling to stop and the character becomes part of a string. This process continues until a command character is selected whereby the string can be sent to a printer, spoken through a speech synthesizer, or erased.</p>","PeriodicalId":76133,"journal":{"name":"Medical instrumentation","volume":"21 2","pages":"97-102"},"PeriodicalIF":0.0,"publicationDate":"1987-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14090815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Comparison of the efficacy of defibrillation with the damped sine and constant-tilt current waveforms in the intact animal. 在完整动物体内,阻尼正弦和恒倾斜电流波形除颤效果的比较。
Medical instrumentation Pub Date : 1987-04-01
M Hinds, G M Ayers, J D Bourland, L A Geddes, W A Tacker, N Fearnot
{"title":"Comparison of the efficacy of defibrillation with the damped sine and constant-tilt current waveforms in the intact animal.","authors":"M Hinds,&nbsp;G M Ayers,&nbsp;J D Bourland,&nbsp;L A Geddes,&nbsp;W A Tacker,&nbsp;N Fearnot","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The efficacy of defibrillation using the damped sine and constant-tile (60%) truncated exponential waveforms was determined in each of nine dogs. Two measures of efficacy were used to compare the two waveforms: 1) threshold defibrillation current and 2) percent successful defibrillation. For both measures of efficacy, shock strength was expressed in terms of delivered energy. Mean threshold energy was 0.98 J/kg for the damped sine wave and it was 1.24 J/kg for the truncated exponential waveform. Percent successful defibrillation versus energy/kg curves were constructed for each of the waveforms and were found to be essentially the same. Percent successful defibrillation increased with increasing shock intensity. For 50% success, the energy for the damped sine wave was 1.16 J/kg; for the truncated exponential wave, the corresponding value was 1.15 J/kg. A shock of threshold intensity successfully defibrillated in approximately 50% of the defibrillation attempts, i.e., defibrillation threshold corresponds to about 50% successful defibrillation.</p>","PeriodicalId":76133,"journal":{"name":"Medical instrumentation","volume":"21 2","pages":"92-6"},"PeriodicalIF":0.0,"publicationDate":"1987-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14735537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A technique for localized tumor hyperthermia in small animals. 小动物局部肿瘤热疗技术。
Medical instrumentation Pub Date : 1987-04-01
C F Gottlieb, N L Block
{"title":"A technique for localized tumor hyperthermia in small animals.","authors":"C F Gottlieb,&nbsp;N L Block","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Hyperthermia, the intentional elevation of tissue temperature above 41 degrees C, is being intensely researched as a therapeutic modality for cancer, especially when used in combination with radiation therapy and/or chemotherapy. A serious impediment to laboratory progress in this area has been the lack of affordable equipment providing control and reproducibility when faced with highly variable factors including tumor size and shape, blood flow, heat conduction, and tissue dielectric discontinuity. Our solution has been the development of a laboratory microwave hyperthermia system, dedicated to the treatment of small, superficial tumors. This system uses a 2.45-GHz microwave generator and custom applicator to noninvasively heat a mass of tissue about 2 cm in diameter and 1.5 cm in depth. Tissue temperature at up to four locations is measured using miniature. Teflonencased thermocouples. The microwave generator and the thermometry are interfaced to a personal computer which provides fully automated hyperthermia treatment reproducible to +/- 0.2 degrees C.</p>","PeriodicalId":76133,"journal":{"name":"Medical instrumentation","volume":"21 2","pages":"75-80"},"PeriodicalIF":0.0,"publicationDate":"1987-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14735534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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