经皮腔内冠状动脉成形术对心脏自主神经活动的影响

目的：观察经皮腔内冠状动脉成形术（ＰＴＣＡ）后心率变异（ＨＲＶ）的变化,探讨ＰＴＣＡ和ＨＲＶ的影响。方法：ＰＴＣＡ患者１２０例,２４ｈ动态心电图（ＤＣＧ）记录ＰＴＣＡ术前１周、术后１周、术后６个月的心电信息并进行ＨＲＶ分析。结果：ＰＴＣＡ术后６个月ＨＲＶ指标中的２４ＲＲ间期标准差（ＳＤＮＮ（和高频段的功率谱密度（ＨＦＰ）较术前明显增高（Ｐ分别不小于０．０５及０．０１）;ＰＴＣＡ术后冠状动脉再狭窄患     

动态血压检测临床意义的探讨

目的 :探讨动态血压检测在临床应用的意义。方法 :采用动态血压检测 (ABPM) ,被检查者分二组 :无高血压病史 ,常规测血压高于正常值 (140 / 90 mm Hg)为 A组 4 0例 ,有高血压病史者为 B组 10 4例。结果 :A组常规测血压平均值为 16 3± 7.3/ 115± 4 .5mm Hg,ABPM平均值为 12 8± 8.2 / 85± 5.0 mm Hg;血压高于 140 / 90 mm Hg超过 50 %占 10 % (4 / 4 0 ) ;杓形曲线占 90 % (36 / 4 0 )。 B组 :常规测血压平均值为 158.5± 10 .6 / 95± 5.5mm Hg,ABPM平均值为 135± 6 .5/ 88± 4 .5mm Hg,血压高于140 / 90 mm Hg,超过 50 %占 19.2 % (2 0 / 10 4 )非杓形曲线占 16 .3% (17/ 10 4 )。结论 :ABPM能更真实地反应被检查者的血压 ,也可以作为评价高血压病人降压疗效的一种方法。     

羊水过少102例临床分析

目的：探讨及早发现和正确地处理羊水过少的方法。方法：对１０２例羊水过少病例,从孕龄,分娩方式与彩超和电子胎心监护的关系及围产儿质量,进行多方面分析。结果：初产妇羊水过少的发生率,明显高于经产妇,晚期妊娠随着孕周的增加,羊水渤少的发生率增高,羊水过少者,胎儿宫内窘迫,新生儿低Ａｐｇａｒ评分发生的危险性增加。结论：晚期妊娠应动态监测羊水量,正确选择分娩时机和方式。     

Monitoring normal and aberrant electrocardiographic activity from an endotracheal tube: Comparison of the surface,esophageal, and tracheal electrocardiograms

Introduction. We designed an endotracheal (ET) tube with orthogonally spaced ECG cuff electrodes. This ET tube was evaluated in dogs and sheep to determine (1) whether ECGs recorded from our tube were sufficient to make accurate clinical decisions concerning heart rate and rhythm; and (2) whether metallic cuff electrodes in direct contact with the trachea could induce mucosal burn injury during episodes of defibrillation.Methods. Using experimental animals, we obtained ECGs from their tracheae and compared our findings with ECGs obtained from surface and esophageal electrodes. The electrical activity of the heart was modified by increasing the depth of anesthesia, occluding the left coronary artery, and administering beta-adrenergic drugs. Before the dogs were euthanized, they were subjected to episodes of transthoracic and intrathoracic defibrillation at energy levels of 200 to 400 J. A postmortem pathological examination of the trachea was performed to determine the incidence of mucosal burn injury.Results. Tracheal electrocardiography provided valid information on heart-rate monitoring and certain morphology profiles. The R-R, PR, QRS, and QT intervals measured from the trachea had a correlation of 1.0, 0.96, 0.83, and 0.98, respectively, when compared with the same intervals obtained from surface electrodes. Two tracheae subjected to intrathoracic defibrillation at >300 J revealed evidence of minor burn injury. Some localized epithelium loss was displayed in all tracheae; we attributed this to tracheal intubation.Conclusion. Tracheal electrocardiography may be useful in trauma patients who require intubation where injury precludes placement of chest ECG electrodes.     

An expert system to teach troubleshooting of common problems associated with the automated anesthesia recordkeeper

Automated anesthesia recordkeepers have been used to monitor patients during surgery in up to 90% of cases at The Ohio State University. The record-keeping devices are complex and can be difficult to troubleshoot. The 1st-CLASS Fusion Program, an expert system shell-program, has been programmed to allow the resident or nurse anesthetist to solve the two most common types of problems associated with the recordkeeper: printer problems and patient monitor problems. Use of this program allows the resident or nurse anesthetist to troubleshoot the recordkeeper quickly and accurately and promotes in the user a sense of competence and control over the technology.     

Cardiac output measurement by the thermodilution method: An in vitro test of accuracy of three commercially available automatic cardiac output computers

Objective To describe the accuracy and the reproducibility of the thermodilution flow measurements obtained using 3 commercially available cardiac output computers commonly used in intensive care units.Design An experimental in vitro study. Twelve different values of control flow (Qctr) were measured (Qmsr) using 3 different cardiac output computers (Abbott Critical Care System, Oximetrix 3 SvO₂/CO Computer, Baxter Oximeter/Cardiac Output Computer SAT-1^TM; American Edwards Laboratories, 9520 A Cardiac Output Computer). Standard equipment and techniques were employed, taking account of the specific weight and heat of warm water relative to blood. In addition, separate sets of measurements were performed in order to investigate the effect on Qmsr of some variables which may influence the indicator loss (time for injection, depth of immersion of the catheter, temperature of the injected fluid).Setting Our laboratory, inside the intensive care unit.Measurements and results The analysis of the linear regression of Qmsr versus Qctr (r values between 0.992 and 0.984; residual standard deviation values comprised between 0.24 and 0.49 l/min; intercepts and slopes not significantly different from identity line), the values of the percentage errors (PE=[Qctr–Qmsr]·100/Qctr; PE mean values 7.9, 5.0 and 13.1), and those of the coefficients of variability (CV=standard deviation mean value, %; CV mean values 5.4, 5.8 and 4.6), show a good level of accuracy and reproducibility of the measurements. Our data confirm previously reported results. Furthermore, the cumulative effect of variables capable of influencing the indicator loss, even if corrected according to the calculation constant the manufacturers provide, was found to result in statistically significant changes of Qmsr.Conclusion The accuracy and reproducibility of the automatic cardiac computers tested is sufficient for practical clinical purpose. It may also depend on the modality of injection of the cooling bolus, which may significantly influence the effective indicator losses.     

A method for the follow-up of clusters of adverse reproductive outcomes

Clusters of adverse reproductive outcomes are reported with increasing frequency to public health authorities. Most are random events and only a very small proportion is likely due to identifiable environmental agents. Often, a preliminary study confirms the existence of a spatial and temporal excess but no biologically plausible cause is found. These cases require a follow-up of incidence to identify any continuing excess. A conceptually simple fixed window technique of follow up is proposed. The power of the test is mainly influenced by the magnitude of the increase in rate, the number of adverse outcomes selected for observation and the acceptable false alarm rate. This technique has several advantages compared with other currently used methods. From a public health point of view, two important factors are to be considered in setting the parameters of the test: the delay in providing an answer for the community and the availability of resources for conducting environmental investigations.     

Biventricular Bypass: Alternative to Univentricular Bypass and Total Artificial Heart–Bridge

Left ventricular and biventricular bypasses (LVBs, BVBs) were performed in 102 experiments in sheep, goats, and donkeys. Biventricular bypass was performed in the assisted circulation mode or in the paracorporeal artificial heart bridge (PCAHB) mode when the natural heart fibrillates. During implantation of artificial ventricles instead of a heart-lung bypass, counterpulsation was used. Several types of connective conduits were developed and tested in experiments. The conduits included bifurcational connective pipes that permit "intake" of blood into artificial ventricles from atria and ventricles of the natural heart simultaneously and consequently provide effective blood flow through shunts not depending on the state of the natural heart (acute cardiac weakness or asystole). Monitoring gas content (PO2, PCO2, and pH) in the myocardium of both ventricles suggested development of right ventricular failure under conditions of LVB before hemodynamic changes occurred and confirmed the preferability of BVB over other methods of assisted circulation, as it is most effective and capable of normalizing short-term cardiac disturbances in the course of the 1st 2 days. Survival time of experimental animals (2-3 days for dogs, 5-12 days for sheep, goats, and donkeys) is sufficient to overcome acute cardiac insufficiency. This suggests that BVB in the assisted circulation mode or PCAHB mode can serve as a bridge for cardiac transplantation for the time of search for the available organ.     

Correlated, simultaneous, multiple-wavelength optical monitoring in vivo of localized cerebrocortical NADH and brain microvessel hemoglobin oxygen saturation

Current forms of brain monitoring, such as electroencephalography (EEG), have had limited clinical utility. The EEG records spontaneous cerebrocortical activity and thus is an indirect indicator of metabolic demand and, to a lesser extent, an indicator of mismatch of supply versus demand. Ischemia modulates EEG activity in ways that can usually be detected, but EEG patterns can be similarly modulated by many other factors, including temperature and pharmacologic manipulation. This in vivo study in physiologically monitored animals evaluated the use of correlated optical spectroscopy, performed with an instrument having a fiberoptic light-guide bundle in contact with the cerebral cortex, for the simultaneous monitoring of cerebrovascular oxygen availability and intracellular oxygen delivery. A highly specific monitor of cerebral intracellular oxygen supply, the cerebrocortical intramitochondrial NADH redox state, was monitored in vivo with a fluorescence technique. Absorption spectroscopy was used concurrently to monitor hemoglobin content (blood volume) and oxygen saturation in the microcirculation. Correlated changes in optical signals from cerebrocortical NADH and hemoglobin were studied in a swine model (n=7) of nitrogen hypoxia. Measurements were made at four wavelengths with a time-division, multiplexed fluorometer/reflectometer. Because the NADH fluorescence signal at 450 nm is affected by local changes in blood volume, a corrected fluorescence signal is usually calculated. In previous studies, where only two wave lengths have been measured, attempts at correction were based on reflectance at the excitation wavelength (366 nm). We compared estimators of changes in microcirculatory blood volume using reflection at two wavelengths: 366 nm and 585 nm, the wavelengths for maximum and isobestic absorption. The results of the studies were as follows: (1) during transient hypoxia, NADH and local hemoglobin saturation signals changed in concert with arterial pulse oximetry, with changes in NADH lagging behind changes in saturation by an average of 5.3 seconds; (2) after hypocapnic ventilation to a mean Paco ₂ of 20.2 ± 0.8 mm Hg, NADH increased by 11.5 ± 8.7% (as compared with maximal change during anoxia), local hemoglobin saturation decreased by 7.7 ± 6.4%, and local blood volume decreased by 12.5 ± 13%, while arterial SpO₂ was unchanged; (3) our two measures of local blood volume were closely correlated during carbon dioxide perturbations, but poorly correlated during hypoxic perturbation; and (4) NADH fluorescence provided a more rapid, sensitive indicator of oxygen deprivation than did the EEG. During transient hypoxia, EEG changes occurred 57.4 ± 10.4 seconds after the onset of decline in local hemoglobin saturation, after NADH had completed 50% of its maximal increase.This work was supported in part by research grants from the NIH (GM34767), the Academic Senate of the University of California, and the UCSF Anesthesia Research Foundation.