医院综合效益评价中的权数（三）——估计权数

在医院综合效益评价中，估计权数由评价专家根据经验对评价指标的重要程度的一种评估，这类数据通常用的ＡＨＰ法进行处理。本文用ＡＨＰ的递推算法计算估计权数，这种算法不仅计算简单，而且易达到一致性的要求，其估计的剩余误差小于ＡＨＰ法。     

Extracorporeal membrane oxygenation (ECMO) as lung or heart assist

Extracorporeal membrane oxygenation (ECMO) may serve as extracorporeal lung assist (ECLA) in patients with acute respiratory failure (ARF) or as extracorporeal heart assist (ECHA) in patients with low output syndrome (LOS) after open heart surgery. From 1988 to 1992 seven patients underwent ECMO in our hospital; four suffered from ARF and three from LOS. Various bypass techniques were employed. Two ARF patients, aged 58 and 18 years, had veno-venous bypass; in the latter, ECMO was reinstituted as a veno-arterial bypass one week after weaning. In a three-year-old boy, the ECMO outflow tubing was primarily connected to the pulmonary artery, and shortly afterwards relocated to the common carotid artery. In a 31-year-old man with ARF, and three LOS patients, a 56-year-old woman, and two men aged 68 and 70 years, ECMO was veno-arterial with direct access to the ascending aorta. A heparin-coated system was used, and all but one patient, who was treated with warfarin, received a daily low dose of heparin, which was withdrawn after from one to nine days.
Six patients were weaned off ECMO after 4.5 to 21 days. Three ARF patients recovered completely; the child died. In one LOS patient, ECMO was withdrawn due to a poor general condition. Two others were weaned off ECMO and the intra-aortic balloon pump, and the inotropic support was significantly reduced, but both died of multiple system organ failure. Although no firm conclusions can be drawn from these few case reports, the heparin-coated system used as ECLA appears promising, whereas ECHA seems to imply a poor prognosis in patients who are not candidates for cardiac transplantation.     

The cold pressor test: Vascular and myocardial response patterns and their stability

The purposes of the present study were to compare the cardiovascular response patterns evoked by three versions of the cold pressor test (either forehead stimulation or hand or foot immersion) and to determine the reproducibility of the responses over a 2-week interval. Blood pressure, heart rate, stroke volume, cardiac output, total peripheral resistance, and systolic time intervals were obtained during rest and during the cold pressor test in 42 young men. Across conditions, the pressor response was supported by peripheral resistance increases with concomitant stroke volume decreases. Although the response panerns were generally similar across sites, exceptions were apparent for heart rate. Forehead stimulation was characterized by no significant change in heart rate, whereas limb (hand or foot) immersion was associated with significant heart rate acceleration. The responses elicited by the three cold pressor test conditions were reliable and showed little evidence of attenuation over the test-retest interval.     

动脉波形分析计算心排出量及临床应用

动脉波形分析技术用于测量心排出量(arterial pressure-based cardiac output,APCO)和每搏输出量变异指数(stroke volume variation,SVV)是一项新的微创血流动力学技术,它能够连续通过对外周动脉的波形特征结合患者的基本信息(年龄、性别、身高、体重等)进行分析测定心排出量(CO),并且不需要通过其他方法来校准.临床上已经显示出可以接受的准确性和良好的即时性和方便性,但也存在一定的局限性,如在一些心脏疾病如主动脉返流、二尖瓣返流或给予α1受体激动药,APCO并不能准确反映心排血量.     

医德重建:传统医德危机及其解决途径探析

目前,我国面临的医德危机是非常严重的。如何解决这一危机就成了一个不容回避的重大课题,不少学者提出要用传统医德来规范医务人员,并以此作为解决该危机的良方。然而,这种以人格伦理为特质的传统医德尽管有其一定的合理性,但其在实践中的有效性却受到了人们的质疑。为此,试图从传统医德自身的局限性、医务人员利益意识的觉醒以及因社会失范而导致的越轨三个方面来分析我国医德危机产生的根源,并为此提出了三条对策。     

Cardiovascular responses in paraplegic subjects during arm exercise

Summary The purpose of this study was to examine cardiovascular responses during arm exercise in paraplegics compared to a well-matched control group. A group of 11 male paraplegics (P) with complete spinal cord-lesions between T6 and T12 and 11 male control subjects (C), matched for physical activity, sport participation and age performed maximal arm-cranking exercise and submaximal exercise at 20%, 40% and 6070 of the maximal load for each individual. Cardiac output (Q _c) was determined by the CO₂ rebreathing method. Maximal oxygen uptake was significantly lower and maximal heart rate (f _c) was sigificantly higher in P compared to C. At the same oxygen uptakes no significant differences were observed inQ _c between P and C; however, stroke volume (SV) was significantly lower andf _c significantly higher in P than in C. The lower SV in P could be explained by an impaired redistribution of blood and, therefore, a reduced ventricular filling pressure, due to pooling of venous blood caused by inactivity of the skeletal muscle pump in the legs and lack of sympathetic vasoconstriction below the lesion. In conclusion, in P maximal performance appears to have been limited by a smaller active muscle mass and a lower SV despite the higher _c,max. During submaximal exercise, however, this lower SV was compensated for by a higherf _c and, thus at the same submaximal oxygen uptake,Q _c was similar to that in the control group.     

Frequency and Output-Dependent Change in Conduction Over Slow Pathways in a Patient with Sustained Ventricular Tachycardia Unrelated to Coronary Artery Disease

In a patient with sustained ventricular tachycardia, we obtained two different paced QRS morphologies from a single pacing site. In one QRS morphology the stimulus to the QRS complex was long, 150 msec, and in the other it was 100 msec. At the paced cycle length of 600 msec and the stimulus output of 4 V, one QRS morphology with the stimulus to the onset of QRS activation (St-QRS) interval of 150 msec was observed. At the paced cycle length of 400 msec, the other QRS morphology with a St-QRS interval of 100 msec was observed alternatively with the former. At the paced cycle length of 353 msec or 316 msec, the latter with a shorter St-QRS interval was exclusively observed. When the stimulus output was increased from 4 to 10 V, keeping with the paced cycle length at 400 msec, the St-QRS interval was shortened from 100 to 80 msec. For the two QRS morphologies with two St-QRS intervals, two slowly conducting pathways would be responsible. The site of the block in the faster pathway must be located at the proximity of the pacing site and the conduction at a shorter paced cycle length would be explained by "supernormal conduction."     

A new closed-system using partially frozen injectate for thermodilution cardiac output determinations

The FI (partially frozen injectate) system, a new closed-system devised by the authors for thermodilution cardiac output determinations, has two major features: 1) it needs no ice-filled receptacle to keep injectate cold because it uses partially frozen injectate, and 2) it can go without monitoring the injectate temperatures during the whole process of cardiac output determinations. The author evaluated the accuracy and reproducibility of cardiac output determinations with the FI system in 10 critically ill patients, as compared with another closed-system (which is commercially available) and the standard open method. The injectate temperatures in the FI system were also measured in vitro. The mean injectate temperature in the FI system was 0.71 ± 0.26°C and 80% of the injectate temperatures were lower than 1.0°C. Even when no monitoring of injectate temperatures was made, the predicated error in the calculated cardiac output resulted as low as 2% with the FI system. The mean cardiac output values were not statistically different between the FI system and the other two systems.(Maruta H, Usuda Y, Okutsu Y et al.: A new closed-system using partially frozen injectate for thermodilution cardiac output determinations. J Anesth 3: 35–39, 1989)     

Changes in the blood supply of the gastrointestinal tract in rats with age

Summary Regional blood flow of the gastrointestinal (GI) tract and cardiac output have been determined in male Sprague-Dawley rats weighing from 30–726 g. The cardiac output (ml/min per kg) was highest in rats weighing 80–100 g. In heavier rats the cardiac output decreased proportionally with the body weight. The gradient of blood flow to the different parts of the GI tract develops step by step. In the weaning period the blood flow (ml/min per g tissue) through the stomach was less than that through the distal parts of the GI tract. However, the blood flow through the small intestine, cecum and large intestine was uniform at this age. In rats weighing 80–100 g the blood flow through both the cecum and large intestine was less than that through the small intestine. The gradient in blood flow through the various segments of small intestine developed last.     

Variability of thoracic impedance cardiograms in man

The variability of thoracic impedance cardiogram signals was studied in a normal population with the objective of determining the effect of different respiratory manoeuvres and the optimal criteria for acquisition of this type of physiological signal. The variability of the first derivative of the thoracic impedance signal (dZ/dt) was determined at each 5ms intervals along the signal as the ensemble confidence limits of 3% and 97% around the coherent average. The results obtained indicate that: (a) signal variability is minimum during respiratory apnea (p<0.05) as compared with apneusis or normal respiration, (b) signal patterns are different during apnea and apneusis, and (c) during normal respiration the cardiac component of the thoracic impedance signal can be extracted from the respiratory noise by coherent average yielding a signal with the same pattern obtained during apnea.