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Is the effectiveness of cardiac ventricular defibrillation dependent upon polarity? 心室除颤的有效性取决于极性吗?
Medical instrumentation Pub Date : 1987-10-01
J C Schuder, H Stoeckle, W C McDaniel, M Dbeis
{"title":"Is the effectiveness of cardiac ventricular defibrillation dependent upon polarity?","authors":"J C Schuder,&nbsp;H Stoeckle,&nbsp;W C McDaniel,&nbsp;M Dbeis","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Studies involving 240 fibrillation-defibrillation episodes via epicardial patch electrodes in 21-27-kg dogs and 480 transthoracic episodes in 100-kg calves are reported. In dogs, 120 episodes involving shocks by a 3.7-A, 5-ms unidirectional rectangular wave of one polarity were interlaced with 120 similar episodes of the reverse polarity. When the upper right ventricular patch was positive with respect to the left ventricular apex patch, 85% of the episodes yielded defibrillation; 78% defibrillated with the reverse polarity. In one series in calves, 120 episodes involving shocks by a 42-A, 4-ms unidirectional rectangular wave of one polarity were interlaced with 120 similar episodes involving the reverse polarity. In a second series, 59-A, 4-ms shocks were employed. In the 42-A series, 38% of the episodes were successful when the upper right electrode was positive with respect to the electrode over the apex, and 28% were successful with the reverse polarity. Corresponding results in the 59-A series were 80% and 68%, respectively. On an unpaired basis, the three p values were 0.19, 0.14, and 0.04, respectively. On a paired basis, all three comparisons yielded significant differences (p less than 0.05). We conclude that in these cases, at least, there is a moderate dependence upon electrode polarity and that our results appear to warrant clinical studies.</p>","PeriodicalId":76133,"journal":{"name":"Medical instrumentation","volume":"21 5","pages":"262-5"},"PeriodicalIF":0.0,"publicationDate":"1987-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14803793","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
Laserthermia: a computer-controlled contact Nd:YAG system for interstitial local hyperthermia. 激光热疗:一种计算机控制的接触Nd:YAG系统，用于间质性局部热疗。
Medical instrumentation Pub Date : 1987-10-01
N Daikuzono, S N Joffe, H Tajiri, S Suzuki, H Tsunekawa, M Ohyama
{"title":"Laserthermia: a computer-controlled contact Nd:YAG system for interstitial local hyperthermia.","authors":"N Daikuzono,&nbsp;S N Joffe,&nbsp;H Tajiri,&nbsp;S Suzuki,&nbsp;H Tsunekawa,&nbsp;M Ohyama","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Contact Nd:YAG laser surgery is assuming a role of greater importance in endoscopic and open surgery, allowing coagulation, cutting, and vaporization with greater precision and safety. A synthetic sapphire probe allows a wider angle of irradiation and diffusion of low power laser energy (less than 5 W) using an interstitial technique for producing local hyperthermia. Sensors placed directly into surrounding tissue or tumor continuously monitor temperature, and a pertinent computer program produces a controlled and stable temperature (e.g., 42 degrees C) over a period of time (e.g., 20-40 min). The Laserthermia system (Surgical Laser Technologies, Inc., Malvern, PA), using the Nd:YAG laser, offers many advantages in the experimental and clinical treatment of carcinoma by local interstitial hyperthermia.</p>","PeriodicalId":76133,"journal":{"name":"Medical instrumentation","volume":"21 5","pages":"275-7"},"PeriodicalIF":0.0,"publicationDate":"1987-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14803795","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
Treatment of port-wine stains: analysis. 酒斑的治疗:分析。
Medical instrumentation Pub Date : 1987-08-01
M J van Gemert, A J Welch
{"title":"Treatment of port-wine stains: analysis.","authors":"M J van Gemert,&nbsp;A J Welch","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Port-wine stains (PWS) are bluish red skin stains that are caused by enlarged, ectatic blood vessels in the dermis. Laser treatment of PWS is analyzed from computation of the spatial distribution of heat production by direct absorption of the laser light and subsequent heat conduction. The absorption and scattering caused by oxyhemoglobin, epidermis, and dermis as a function of wavelength are utilized in this analysis. Ideal treatment is defined as coagulating the ectatic blood vessels without irreversible damage to the epidermis and dermis. The analysis shows that a millisecond pulsed, yellow dye laser at 577 nm (one of the large absorption bands in blood) is the laser of choice to treat PWS, offering as close to the \"ideal treatment\" as possible. The blue-green argon laser, which is currently the most frequently used laser for this purpose, is strongly recommended with irradiation times in milliseconds. Other lasers that are in clinical use, such as the red ruby and near-infrared Nd-YAG lasers, can provide selective treatment only when the epidermis is cooled concurrently. The CO2 laser, on the other hand, can coagulate the blood vessels only through heat conduction from the hot epidermis; hence, it has neither the treatment selectivity nor any other physical option to force this selectivity.</p>","PeriodicalId":76133,"journal":{"name":"Medical instrumentation","volume":"21 4","pages":"213-7"},"PeriodicalIF":0.0,"publicationDate":"1987-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14574906","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 physical properties of tissue ablation with excimer lasers. 准分子激光组织烧蚀的物理性质。
Medical instrumentation Pub Date : 1987-08-01
F W Cross, T J Bowker
{"title":"The physical properties of tissue ablation with excimer lasers.","authors":"F W Cross,&nbsp;T J Bowker","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The current controversy regarding the interaction between the output of the excimer laser and human tissue concerns the relative importance of photothermal and photoablative effects. Two experiments using an excimer laser on vascular tissue, aimed at defining the precise laser-tissue interaction, were performed. The experiments argue strongly in favor of photoablative effects that result from multiple photon interactions with ablated tissue.</p>","PeriodicalId":76133,"journal":{"name":"Medical instrumentation","volume":"21 4","pages":"226-30"},"PeriodicalIF":0.0,"publicationDate":"1987-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14574909","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
Treatment of port-wine stains at 577 nm: clinical results. 577 nm处理葡萄酒色斑:临床结果。
Medical instrumentation Pub Date : 1987-08-01
O T Tan, T J Stafford
{"title":"Treatment of port-wine stains at 577 nm: clinical results.","authors":"O T Tan,&nbsp;T J Stafford","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>A pulsed, dye laser at 577 nm was used to treat 65 patients with port-wine stains. Results clearly indicate that the laser parameters of dose, wavelength, and pulse duration contribute to the outcome of laser treatment of port-wine stains.</p>","PeriodicalId":76133,"journal":{"name":"Medical instrumentation","volume":"21 4","pages":"218-21"},"PeriodicalIF":0.0,"publicationDate":"1987-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14574907","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
Laser applications in clinical medicine. 激光在临床医学中的应用。
Medical instrumentation Pub Date : 1987-08-01
J A Pearce
{"title":"Laser applications in clinical medicine.","authors":"J A Pearce","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Laser energy sources have been used in a wide range of clinical applications over the last decade to obtain cutting, coagulation, and denaturization of tissue. The therapeutic effect depends on complex interaction among the optical and thermal properties of tissue and damage accumulation. In applications where localized white coagulum is required, there are trade-offs between continuous activation using a large spot size and repetitive pulses with a small spot size as well as between a highly scattered, deep penetration source and a highly absorbed, shallow penetration laser source. For applications involving ablation of tissue, high intensity, pulsed, shallow penetration sources have many advantages over continuously activated penetrating sources. In this article, the range of applications is reviewed with particular attention to the underlying physical phenomena that influence the choice of treatment parameters.</p>","PeriodicalId":76133,"journal":{"name":"Medical instrumentation","volume":"21 4","pages":"209-12"},"PeriodicalIF":0.0,"publicationDate":"1987-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14574905","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
Tissue welding using a low energy microsurgical CO2 laser. 使用低能显微外科CO2激光进行组织焊接。
Medical instrumentation Pub Date : 1987-08-01
S Thomsen, J R Morris, C R Neblett, J Mueller
{"title":"Tissue welding using a low energy microsurgical CO2 laser.","authors":"S Thomsen,&nbsp;J R Morris,&nbsp;C R Neblett,&nbsp;J Mueller","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>A low energy, CO2 laser adapted specifically for microsurgery can be used to assist in anastomosis by \"welding\" tissue through thermal coagulation. Which tissue constituents contribute to the bond are not known, and different constituents may be important in welding different organs.</p>","PeriodicalId":76133,"journal":{"name":"Medical instrumentation","volume":"21 4","pages":"231-7"},"PeriodicalIF":0.0,"publicationDate":"1987-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14574910","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 new device for continuous ambulatory central venous pressure measurement. 一种连续动态中心静脉压测量装置。
Medical instrumentation Pub Date : 1987-08-01
J C Buckey, R L Goble, C G Blomqvist
{"title":"A new device for continuous ambulatory central venous pressure measurement.","authors":"J C Buckey,&nbsp;R L Goble,&nbsp;C G Blomqvist","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>We have developed a device for continuous direct measurement of human central venous pressure (CVP) during space flight. Normal resting CVP is typically in the range of 5-10 mmHg; in zero gravity, the expected changes are +/- 5 mmHg or less. A 1-mm Hg change in CVP can represent a substantial intravascular fluid shift. The device is small, battery powered, and designed to run for at least 24 hr. Pressure is measured in a saline solution-filled catheter inserted into a central vein. The transducer is placed in the axilla at the level of the catheter tip to offset hydrostatic gradients. A pump and an electronic system mount on the leg. This assembly provides a slow, continuous infusion of heparinized saline solution to maintain the patency of the catheter. The electronic system generates a digital display in mm Hg, an analog output, and a visible and audible alarm for excessive pressure. An air-filled syringe allows for a two-point calibration (zero and a positive pressure generated by measured compression of a known gas volume). A two-failure tolerant system minimizes electric shock hazards. Two latex diaphragms separate the saline solution from the transducer surface, and the electronic system and pump chamber are in separate enclosures. A clear polycarbonate case allows bubbles to be seen. The unit has been tested for pump function, temperature stability, drift, and accuracy. We conclude that this approach provides a unit with sufficient stability, accuracy, and temperature insensitivity for measuring ambulatory CVP for up to 28 hr. The design may be suitable for ambulatory measurement of other intravascular and intracardiac pressures.</p>","PeriodicalId":76133,"journal":{"name":"Medical instrumentation","volume":"21 4","pages":"238-43"},"PeriodicalIF":0.0,"publicationDate":"1987-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14574911","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
Development of controlled Nd:YAG laser for medical applications. 医用可控Nd:YAG激光器的研制。
Medical instrumentation Pub Date : 1987-08-01
S R Mordon, A H Cornil, B Buys, J P Sozanski, J M Brunetaud, Y Moschetto
{"title":"Development of controlled Nd:YAG laser for medical applications.","authors":"S R Mordon,&nbsp;A H Cornil,&nbsp;B Buys,&nbsp;J P Sozanski,&nbsp;J M Brunetaud,&nbsp;Y Moschetto","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Several medical fields are concerned with applications of thermal lasers such as neodymium-doped, yttrium aluminum garnet (Nd:YAG), argon, and CO2. However, quantification of the necrotic volume of Nd:YAG laser-induced damage is not possible at the time of treatment. Mathematic models and feedback control can help to optimize Nd:YAG laser treatments. We therefore formulated mathematic models for coagulation processes and developed an intelligent Nd:YAG laser system with closed-loop feedback control. Surface temperature evolution proved to be valuable data for real-time control of coagulation and ablation. Infrared thermometry provided the noncontact measurement of temperature. A computer stored the temperature data calculated by the mathematic model. Deviations of surface temperature during the treatment beyond established tolerances causes the Nd:YAG laser system to adjust the laser power automatically.</p>","PeriodicalId":76133,"journal":{"name":"Medical instrumentation","volume":"21 4","pages":"222-5"},"PeriodicalIF":0.0,"publicationDate":"1987-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14574908","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
Simultaneous comparison of three noninvasive oximeters in healthy volunteers. 三种无创血氧仪在健康志愿者中的同时比较。
Medical instrumentation Pub Date : 1987-06-01
Y Mendelson, J C Kent, A Shahnarian, G W Welch, R M Giasi
{"title":"Simultaneous comparison of three noninvasive oximeters in healthy volunteers.","authors":"Y Mendelson,&nbsp;J C Kent,&nbsp;A Shahnarian,&nbsp;G W Welch,&nbsp;R M Giasi","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Noninvasive monitoring of arterial hemoglobin oxygen saturation (SaO2) from the Nellcor N-100 and the Ohmeda-Biox 3700 pulse oximeters were compared with SaO2 measured simultaneously by the Hewlett-Packard 47201A ear oximeter. A total of 868 pairs of data points ranging in saturation from 55-100% were obtained from 31 healthy adult volunteers of different ages, sex, skin pigmentation, height, weight, hematocrit, and smoking habits. Steady state and rapidly changing hypoxic conditions were achieved by varying the inspired O2 concentration between 10 and 100%. Measurements were analyzed by means of linear regression. The equations for the best fitted linear regression line between the Nellcor and the Ohmeda-Biox pulse oximeters as compared to the reference Hewlett-Packard ear oximeter readings were Y = 0.92X + 7.45 and Y = 1.10X - 10.73, respectively. Our study showed that despite a very close correlation among these three oximeters (r = 0.98), when compared to the Hewlett-Packard ear oximeter, the Nellcor pulse oximeter overestimates SaO2 by 2-4%, whereas the Ohmeda-Biox pulse oximeter underestimates SaO2 by 3-6% for SaO2 levels between 70 and 55%.</p>","PeriodicalId":76133,"journal":{"name":"Medical instrumentation","volume":"21 3","pages":"183-8"},"PeriodicalIF":0.0,"publicationDate":"1987-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14735346","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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