小儿体外循环采用中度低温低流量灌注技术的临床研究

目的研究先天性心脏病患儿体外循环手术中采用中度低温合并低流量灌注技术的可行性。方法３０例手术患儿体外循环降温至肛温２５．６±０．８４℃，食管温度２４．１±１．３２℃，鼓膜温度２３．８±１．４１℃，维持流量１．２３±０．０９Ｌ／ｍｉｎｍ２，转流时间９５．４±３４．６分钟，主动脉阻断时间５１．４±２０．２分钟，低流量维持时间４５．７±２２．４分钟。结果低流量灌注时静脉血氧饱和度均在８０％以上，除１例外，其余均无缺氧酸中毒的血气表现，血乳酸值也未升高，术后恢复良好。结论中度低温体外循环选用低流量灌注可满足机体代谢的需要，有利于减少长时间高流量灌注的不良反应。     

Intrathoracic pressure fluctuations move blood during CPR: Comparison of hemodynamic data with predictions from a mathematical model

Whether blood flow during cardiopulmonary resuscitation (CPR) results from intrathoracic pressure fluctuations or direct cardiac compression remains controversial. We developed a mathematical model that predicts that blood flow due to intrathoracic pressure fluctuations should be insensitive to compression rate over a wide range but dependent on the applied force and compression duration. If direct compression of the heart plays a major role, however, the model predicts that flow should be dependent on compression rate and force, but above a threshold, insensitive to compression duration. These differences in hemodynamics produced by changes in rate and duration form a basis for determining whether blood flow during CPR results from intrathoracic pressure fluctuations or from direct cardiac compression. The model was validated for direct cardiac compression by studying the hemodynamics of cyclic cardiac deformation following thoracotomy in four anesthetized, 21–32-kg dogs. As predicted by the model, there was no change in myocardial or cerebral perfusion pressures when the duration of compression was increased from 15% to 45% of the cycle at a constant rate of 60/min. There was, however, a significant increase in perfusion pressures when rate was increased from 60 to 150/min at a constant duration of 45%. The model was validated for intrathoracic pressure changes by studying the hemodynamics produced by a thoracic vest (vest CPR) in eight dogs. The vest contained a bladder that was inflated and deflated. Vest CPR changed intrathoracic pressure without direct cardiac compression, since sternal displacement was <0.8 cm. As predicted by the model and opposite to direct cardiac compression, there was no change in perfusion pressures when the rate was increased from 60 to 150/min at a constant duration of 45% of the cycle. Manual CPR was then studied in eight dogs. There was no surgical manipulation of the chest. Myocardial and cerebral blood flows were determined with radioactive microspheres and behaved as predicted from the model of intrathoracic pressure, not direct cardiac compression. At nearly constant peak sternal force (378–426 N), flow was significantly increased when the duration of compression was increased from short (13%–19% of the cycle) to long (40%–47%), at a rate of 60/min. Flow was unchanged, however, for an increase in rate from 60 to 150/min at constant compression duration. In addition, myocardial and cerebral flow correlated with their respective perfusion pressures. Thus vital organ perfusion pressures and flow for manual external chest compression are dependent on the duration of compression, but not on rates of compression of 60 and 150/min. These data are of course similar to those produced by vest CPR, where intrathoracic pressure is manipulated without sternal displacement, and to those predicted for movement of blood by intrathoracic pressure changes. These data are, however, opposite to those produced by cardiac deformation and to those predicted for movement blood by direct cardiac compression. We conclude that intrathoracic pressure fluctuations generate blood flow during manual CPR.     

Spontaneous arterial baroreflex control of the heart rate during head-down tilt in heat-stressed humans

The purpose of this study was to elucidate the effect of raised body temperature per se during acute heat stress on the spontaneous arterial baroreflex control of heart rate (f _c) in humans. To investigate whether unloading of cardiopulmonary baroreceptors during whole-body heating would alter the arterial baroreflex control of f _c, we controlled loading of the cardiopulmonary baroreceptors by head-down tilt (HDT) at angles of 5°, 10°, 15°, and 30° during heat stress produced by hot-water-perfused suits. The sensitivity of the arterial baroreceptor-cardiac reflex was calculated from the spontaneous changes in beat-to-beat arterial pressure and f _c. As an index of cardiopulmonary baroreceptor loading, the left atrial diameter (LAD) was measured by echocardiography. During whole-body heating, the LAD decreased with the rising body core temperature and increased with the HDT. The decreased LAD during heating almost recovered to the normothermic control level by 10° HDT. In the supine position, cardiac baroreflex sensitivity remained unchanged during heating. Arterial pressure, f _c and cardiac baroreflex sensitivity were not changed by HDT ranging from 5° to 30° during heating. These results suggest that cardiac baroreflex sensitivity remain unchanged during graded loading of the cardiopulmonary baroreceptors in heat-stressed humans. Also, we conclude that the sensitivity of the spontaneous arterial baroreflex controlling the f _c is not influenced by raised body temperature per se during acute heat stress. Electronic Publication     

Morphological inspection of 80 consecutive Gyro pumps after cardiopulmonary bypass

 We have been using the Gyro centrifugal pump C1E3 for cardiopulmonary bypass in anticipation of high efficiency, low hemolysis, and antithrombogenicity of this pump. However, the clinical evaluation of this pump remains to be clarified, because it has been a short time since the pump appeared in clinical situations. The aim of the present study is to inspect and analyze the Gyro pumps morphologically after clinical use. We examined 80 consecutive pumps after cardiopulmonary bypass for 186 ± 67 min with a mean flow rate of 2.52 ± 0.22 l/min/m² at a mean rotational speed of 2485 ± 81.1 rpm. Although no abnormal findings were present in 79 pumps, one pump was found to contain effusion at the connection between the impeller body and the shaft. The extudate was supposed to be blood, based upon the results of X-ray spectrometer analysis. The cause was determined to be the upward deviation of the shaft off the impeller body. Scanning electron microscopy showed scratches on a part of the bottom housing and a smooth surface of both the male and female pivots of the pump. Surface profile measurement revealed that the deformity of the female pivots was 0.14 mm (top) and 0.05 mm (bottom). These observations suggest that the floating force and vibration by the rotating impeller acted on the joint zone between the alumina ceramic shaft and the polycarbonate impeller body, resulting in dissection of the adhesive agent from the polycarbonate. Although this abnormality may be rare, the structural design still may need to be improved. Received: November 9, 2001 / Accepted: February 4, 2002     

深低温体外循环对犬趾蹼微循环指标的研究

本研究表明,深低温体外循环时,犬趾蹼微循环发生的变化与温度有关。平均动脉压(MAP)的变化不能反映组织灌注的优劣情况。毛细血管内的血流速度与灌注流量的高低有关。     

不同类型心脏患者心内直视手术期间呼气末CO2分压与动脉血CO2分压及其差值的变化

目的探讨不同类型心脏患者心内直视手术期间呼气末二氧化碳分压（PETCO2）与动脉血二氧化碳分压（PaCO2）的相关性及二者差值[P（a-ET）、CO2]的临床意义。方法45例患者分成3组，每组15例。A组：左向右分流组；B组：无分流组；C组：右向左分流组。3组分别于术前（T0）、插管后15min（T1）、手术开始时（T2）、转流前（T3）、转流停止后15min（T4）、术毕时（T5）共6个时点，用旁气流法监测PETCO2，同时抽动脉血测定PaCO2，应用直线回归分析3组各时点PETCO2与PaCO2的相关性，同时计算并分析各组不同时点的P（a-ET）CO2。结果（1）A组、B组各时点PETCO2与PaCO2呈正相关，A组r为0．70—0．85（P〈0．01），B组r为0．71—0．79（P〈0．01）；C组麻醉开始至转停后PETCO2与PaCO2均无相关（0．46—0．54，P〉0．05），而到术毕时则呈正相关（r=0．66，P〈0．05）。（2）3组患者转流前的P（a-ET）CO2变化不大，停转流后A组、B组P[a-ET）CO2增加，其中以A组增加较明显（P〈0．01），而C组P（a-ET）CO2显著减少（P〈0．05）。结论无分流或左向右分流心脏患者在体外循环转流前后PETCO2与PaCO2的相关性较好；右向左分流心脏患者转流前的相关性较差，心内畸形纠正后其相关性可发生变化。P（a-ET）CO2在不同的心脏患者之间差异较大，必须与PaCO2相结合，才能正确指导临床。     

Why did persons invited to train in cardiopulmonary resuscitation not do so?

All citizens (N = 22066) aged 16 to 65 of a medium-sized Belgiantown were personally invited to CPR training sessions held intheir neighbourhood. 1152 responded by attending a trainingsession. Those who did not so respond were surveyed (randomsample N=600) for reasons of their not coming. The sample fittedwell with census data for gender, age and suburb location butnot for job, because retired persons and women at home wereover represented. 123 persons did not want to answer the questions. 116 personssaid they were already trained in CPR, 276 said they would accepton a future occasion and 82 said they would not. Three personsdid not answer this question. There was no discrimination for job, gender and suburb locationbetween those who did and did not accept a future training opportunity,nor was the existence of a heart patient among relatives. Theolder the person, the less inclined was that person to participatein CPR training (age effect x² = 17.17, d.f. = 9, P<0.05).The 276 who accepted future training, chose their workplace(221) and/or their social meeting place (club etc.) as the placewhere this future training should be held. We suggest that CPR training is well accepted and that the trainingopportunities should be given at places of work and social gatherings.     

Endobronchiale Applikation von Adrenalin in der kardiopulmonalen Reanimation Pharmakokinetische und -dynamische Untersuchungen beim Hund

Zusammenfassung Das Ziel der vorliegenden Untersuchungen bestand darin, das pharmakokinetische Profil von Adrenalin bei endobronchialer (e.b.) und intravenöser (i.v.) Applikation zu erarbeiten und die gemessenen Adrenalin-Plasmaspiegel mit hämodynamischen Messungen zu korrelieren. Die e.b. Applikation von 100 g/kg Adrenalin erwies sich als ebenso effektiv, wie die i.v.-Gabe von 10 g/kg. Dabei war der Wirkungseintritt der e.b.-Gabe von Adrenalin nur geringfügig um einige Sekunden verzögert. Die Bioverfügbarkeit für e.b. verabreichtes Adrenalin lag zwischen 80 und 85%. Der therapeutische Effekt blieb nach e.b.-Applikation von 100 g/kg Adrenalin wesentlich länger erhalten (ca. 30 min) als nach i.v.-Gabe von 10 g/kg (ca. 3–5 min). Aus den Ergebnissen wird geschlossen, daß die tiefe endobronchiale Instillation von 2–3 mg Adrenalin (verdünnt in 5–10 ml Kochsalzlösung) als alternative Dosierungstechnik bei klinischen Reanimationen betrachtet werden kann.

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Pharmacokinetics and -dynamics of epinephrine administered endobronchially

Summary The present animal study was designed to investigate the pharmacokinetic behavior of epinephrine after endobronchial (e.b.) and intravenous (i.v.) administration and its correlation to pharmacodynamic measurements. We found the effectiveness of e.b.-epinephrine (100 g/kg BW) to be in the same magnitude as i.v.-epinephrine (100 g/kg BW) with only a slight delay in the pharmacodynamic onset of a few seconds. The bioavailability of e.b.-administration of epinephrine was in the range of 80–85%. The therapeutic effect of e.b.-epinephrine (100 pg/kg BW) lasted much longer (30 min) when compared to i.v.-epinephrine (10 g/kg BW) where the pharmacodynamic effect was terminated after 3 to 5 min. For the clinical situation of cardiopulmonary resuscitation a dose of 2–3 mg epinephrine in 5–10 ml of physiological saline instilled deeply into the bronchial system should be considered as alternative administration technique with fast onset and good effectiveness.

Herrn Prof. Dr. Dr. h.c. F. Stelzner zum 65. Geburtstag gewidmet     

美国医保支付制度改革对我国康复护理服务的启示

梳理了美国医保支付制度改革进程,总结了捆绑支付模式内涵及其对康复护理服务的影响。结合我国国情,借鉴美国医保支付制度改革经验,认为我国应建立基于价值评价的康复护理服务医保支付制度,充分发挥医保基金的引导和保障作用,健全多元化的复合型医保支付体系,创建“以人民的健康为中心”的连续型医疗服务保障体系。