Doppler flow velocity measurements in patients with intracranial hypertension

Summary In patients with severe brain lesions monitoring of the intracranial pressure as well as monitoring of cerebral blood flow can be of clinical value. While at the moment there is no atraumatic method for measuring cerebral blood flow in man, it is recommended to measure blood flow velocity with the ultrasound Doppler technic in the common carotid artery. On theoretical grounds a positive correlation between cerebral blood flow and blood flow velocity can be expected and the observations presented show that such a correlation exists in normal controls and in neurological patients. In many neurological patients the flow velocity in the common carotid artery decreases with increasing intracranial pressure. This suggests that the autoregulation is disturbed. The demonstration of such a disturbance can have clinical implications.

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Zusammenfassung Bei Patienten mit ernsten Läsionen im Gehirn kann Monitoring von sowohl intercraniellem Druck als auch der zerebralen Blutdurchströmung für die Klinik von Bedeutung sein. Da im Moment keine atraumatische Methode für die Messung der zerebralen Blutdurchströmung besteht, wird anempfohlen, die Durchströmungsgeschwindigkeit mit der Ultraschall-Doppler-Technik in der Arteria carotis communis zu messen. Theoretisch kann eine positive Korrelation zwischen der zerebralen Blutdurchströmung und der Strömungsgeschwindigkeit erwartet werden.Die beschriebenen Ergebnisse zeigen, daß tatsächlich ein solcher Zusammenhang besteht, sowohl bei gesunden Versuchspersonen als auch bei neurologischen Patienten.Bei vielen dieser Patienten nimmt die Durchströmungsgeschwindigkeit in der Arteria carotis communis ab bei einer Zunahme des intracraniellen Druckes. Dies suggeriert eine gestörte Autoregulation. Das Aufzeigen einer solchen Störung kann klinische Bedeutung haben.

     

Acute changes in forearm haemodynamics produced by cigarette smoking in healthy normotensive non-smokers are not influenced by propranolol or pindolol

Summary The aim of the present study was to examine the effect of cigarette smoking in healthy non-smokers on blood pressure and forearm haemodynamics after acute oral administration of non-selective -adrenoceptor blockers with and without intrinsic sympathomimetic activity, viz. pindolol 15 mg and propranolol 80 mg. A preliminary study was done to compare cigarette smoking and sham smoking to evaluate the time-course of the haemodynamic effects of cigarette smoking. The second experiment was then carried out in the same six volunteers, according to a double-blind randomized placebo-controlled crossover design, to evaluate the possible effect of pre-treatment with -adrenoceptor blockers on blood pressure, heart rate and forearm haemodynamics (forearm blood flow, brachial artery diameter and brachio-radial pulse-wave velocity) measured at baseline, during smoking and every five minutes up to 1 h afterwards.No major difference from placebo in blood pressure or forearm haemodynamics was found and pre-treatment with beta-blockers did not prevent the acute vascular effects of cigarette smoking.     

Systolic arterial pressure determination by a new pulse monitor technique

The Doppler ultrasound (DUS) technique is a widely accepted non-invasive technique to estimate systolic blood pressure (SBP) accurately in paediatric patients. The DUS has a number of limitations. A new pulse monitor, Mr Pulse (MP), operating on the principle of a finger plethysmograph, was developed to offer an alternative technique to estimate SBP. From 104 paired SBP measurements taken in 16 paediatric patients undergoing general anaesthesia, SBP determined by the MP technique correlated closely with that by the standard DUS technique (r2 = 0.98). Analysis of degree of agreement performed indicated that there was good agreement between SBP obtained by the MP and the DUS techniques. The mean +/- standard deviation of differences in paired SBP values between the two measurement techniques was 0.55 +/- 3.59 mmHg. Mr Pulse is as accurate as the DUS technique in estimating SBP and has the advantage of less critical sensor positioning as it is not subject to electrical interference. It has no electrical hazard.     

Measurement of cardiac output-transtracheal Doppler versus thermodilution

The ABCOM 1 transtracheal Doppler (TTD) has been developed as a non-invasive cardiac output monitor. With this device, cardiac output is continuously calculated from ascending aortic blood flow velocity and aortic diameter obtained via an ultrasound transducer incorporated into the tip of an endotracheal tube. We evaluated the clinical use of the ABCOM 1 monitor and compared cardiac outputs obtained using the TTD system with simultaneous thermodilution (TD) measurements. We found the operation of the ABCOM 1 monitor to be difficult and time-consuming. In our operating rooms, acceptable Doppler signal quality was difficult to obtain. There was no correlation between 36 simultaneously obtained TTD and TD cardiac output measurements. The average difference between measurement techniques and the limits of agreement were unacceptably large (mean difference = 3.04 L.min-1, mean +/- 2 SD = -6.04 to 12.48 L.min-1). Separately analyzing only those measurements during which Doppler signal quality was adequate did not improve agreement between TTD and TD measurements. On the basis of these findings, TTD cannot be recommended as a clinical cardiac output measurement technique.     

Echocardiographic and color flow Doppler assessment of systemic and pulmonary venous connection and drainage in the neonate with congenital heart disease

Systemic and pulmonary venous anomalies are frequently encountered either as isolated lesions or as a significant component of a more complex lesion in the newborn infant with congenital heart disease. Two-dimensional echocardiography and Doppler techniques (conventional and color flow) have become the primary diagnostic imaging modality in this setting. Precise pre-operative definition of these variable venous connection and drainage patterns is critical as the required surgical procedure may solely be based on exact understanding of the veins' anatomy and physiology. On the systemic venous site, anomalies of superior and inferior venae cavae, innominate vein, and coronary sinus can be equally well imaged with either echocardiography or angiography. However, on the pulmonary venous site, echocardiography and Doppler techniques including color flow mapping are superior to angiography for precise definition of the connection and drainage sites of the individual pulmonary veins.     

激光多普勒血流成像技术对针灸效果的观察

目的　应用激光多普勒血流成像系统显示艾灸的治疗效果 ,了解这一新的医学影象技术在针灸经络研究中的应用价值。方法　使用激光多普勒血流成像仪 ,对 12例健康人体艾灸前后体表出现的血流变化予以大范围地显像 ,分析体表血流分布与艾灸作用的关系。结果　 (1)艾灸内关穴后 ,手掌部血流的增加以大小鱼际和内关穴区为主。(2 )艾灸外关穴后 ,指根部的血流增加显著。 (3)不艾灸对照组在 30 min内前臂、手掌和手背血流的自然波动较小。结论　艾灸可以引起手部微循环血流量的增加 ,激光多普勒血流成像仪能够以大范围成像方式显示该过程 ;新的血流成像技术将在针灸经络的研究中具有实用价值     

The value of MRI in diagnosing vascular abnormalities causing stridor

In a 2 year period seven patients who presented with stridor, without respiratory compromise, and three patients without obstructive symptoms were prospectively selected, and underwent MRI. In eight patients with a vascular ring and a pulmonary sling, MRI delineated the vascular abnormality and normal great vessels were found in two patients. Conclusion MRI successfully delineates the great vessels and demonstrates the presence of a vascular ring and pulmonary sling. Received: 15 May 1996 / Accepted: 17 January 1997     

Echocardiographic assessment of patent ductus arteriosus shunt flow pattern in premature infants

AIMS—To identify the patent ductus arteriosus (PDA) shunt flow pattern using Doppler echocardiography; and to assess whether it could be used to predict the development of clinically significant PDA.
METHODS—Premature infants weighing under 1500 g, who required mechanical ventilation, and in whom daily echocardiography could be performed from day 1 until the ductus closed, and on day 7 to confirm closure, were studied. The PDA shunt flow was identified from four Doppler patterns, and the closed pattern of a closed duct was also presented. Clinically significant PDA was diagnosed when there was colour Doppler echocardiographic evidence of left to right ductal shunt associated with at least two of the following clinical signs: heart murmur (systolic or continuous); persistent tachycardia (heart rate>160/min); hyperactive precordial pulsation; bounding pulses; and radiographic evidence of cardiomegaly or pulmonary congestion.
RESULTS—Of 68 infants enrolled into this study, clincally significant PDA developed in 31. The most recordable sequence of transition change of shunt flow pattern for clinically significant PDA was: pulmonary hypertension pattern, to growing pattern, to pulsatile pattern, to closing pattern, to closed pattern. And that for non-clinically significant PDA was: pulmonary hypertension pattern, to closing pattern, to closed pattern. The growing and the pulsatile patterns were mostly documented in infants with clinically significant PDA. The first documented growing pattern to predict clinically significant PDA gave a sensitivity of 64.5% and a specificity of 81.1%; the first documented pulsatile pattern gave a sensitivity of 93.5% and a specificity of 100%.
CONCLUSION—Doppler echocardiographic assessment of PDA shunt flow pattern during the first 4 days of life is useful for predicting the development of clinically significant PDA in premature infants. At that stage, the closing or closed Doppler pattern indicates that infants are not at risk of developing clinically significant PDA; the growing or pulsatile Doppler pattern indicates a continuing risk of developing clinically significant PDA.

     

米非司酮用于足月妊娠引产时脐动脉血流的测定

目的：评价米非司酮用于足月妊娠引产时对胎盘血液供应的影响。方法：将９７例妊娠３８～４２周具有引产指征的孕妇随机分为两组：治疗组（４９例）给予口服米非司酮，每次５０ｍｇ１２小时１次连续２天后，阴道置米索前列醇２５μｇ，１２小时１次；对照组（４８例）予静脉推注蒂洛安２００ｍｇ，每日１次连续３天后，静脉点滴催产素引产。两组孕妇均在用药前及用药后３６～４８小时行脐动脉血流速度测定，以收缩期血流速度峰值（Ｓ）与舒张末期血流速度峰值（Ｄ）的比值（Ｓ／Ｄ）为测定参数，观察用药前及用药后３６～４８小时的脐血流Ｓ／Ｄ值的改变。结果：两组用药前及用药后３６～４８小时的脐血流Ｓ／Ｄ值比较，差异无显著性（Ｐ＞０．０５）。结论：米非司酮５０ｍｇ１２小时１次连续２天口服用于足月妊娠引产不仅效果良好，且对胎盘血流动力学无显著影响。     

阴道彩超检测卵巢动脉主干血流对卵巢肿瘤定性诊断的研究

目的：研究用阴道彩色超声多普勒血流显象（ＴＶＳ－ＣＤＦＩ）技术检测卵巢动脉主干血流定性诊断卵巢肿瘤。方法：应用ＴＶＳ—ＣＤＦＩ技术检测正常妇女５６例、卵巢良性肿物６２例及卵巢恶性肿瘤３２例卵巢动脉总干血流的Ａ（收缩期末血流速度峰值）、Ｂ（舒张期末血流速度峰值）、ＰＩ（搏动指数）、ＲＩ（阻力指数）值，并观察其图型特点。结果：卵巢恶性肿瘤的Ｂ、ＰＩ、ＲＩ与正常卵巢及良性肿瘤测值差异有显著性（Ｐ＜０．０５）；恶性卵巢肿瘤内血管为低阻力血管，卵巢动脉主干也随之发生变化，致ＰＩ、ＲＩ降低；将ＰＩ＝１．２０，ＲＩ＝０．６２作为诊断卵巢恶性肿瘤的界值，其灵敏度、特异度、阳性预测值、阴性预测值指标与声像图诊断相比，均明显提高。结论：ＴＶＳ－ＣＤＦＩ检测卵巢动脉总干血流对鉴别卵巢肿瘤的良、恶性具有重要的意义。