BACKGROUND AND PURPOSE: External counterpulsation (ECP) is a noninvasive method used to enhance cerebral perfusion by elevating the blood pressure in ischemic stroke. However, the response of the beat-to-beat blood pressure variability (BPV) in ischemic stroke patients during ECP remains unknown. METHODS: We enrolled recent ischemic stroke patients and healthy controls. Changes in the blood flow velocities in bilateral middle cerebral arteries and the continuous beat-to-beat blood pressure before, during, and after ECP were monitored. Power spectral analysis revealed that the BPV included oscillations at very low frequency (VLF; <0.04 Hz), low frequency (LF; 0.04-0.15 Hz), and high frequency (HF; 0.15-0.40 Hz), and the total power spectral density (TP; <0.40 Hz) and LF/HF ratio were calculated. RESULTS: We found that ECP significantly increased the systolic and diastolic blood pressures in both stroke patients and controls. ECP decreased markedly the systolic and diastolic BPVs at VLF and LF and the TP, and the diastolic BPV at HF when compared with baseline. The decreases in diastolic and systolic BPV reached 37.56% and 23.20%, respectively, at VLF, 21.15% and 12.19% at LF, 8.76% and 16.59% at HF, and 31.92% and 23.62% for the total TP in stroke patients, which did not differ from those in healthy controls. The change in flow velocity on the contralateral side was positively correlated with the total TP systolic BPV change induced by ECP (r=0.312, p=0.035). CONCLUSIONS: ECP reduces the beat-to-beat BPV when increasing the blood pressure and cerebral blood flow velocity in ischemic stroke patients. ECP might be able to improve the clinical outcome by decreasing the beat-to-beat BPV in stroke patients, and this should be explored further in future studies.
Blood Flow Velocity ; Blood Pressure* ; Cerebrovascular Circulation* ; Counterpulsation* ; Humans ; Methods ; Middle Cerebral Artery ; Perfusion ; Stroke*

Pulsatile blood flow plays an important role in maintaining normal vascular endothelial function. Quantitative measurement of pulsatility of human arterial blood pressure and the influence of enhanced external counterpulsation (EECP) on the pulsatility were investigated in this study. Eight healthy young male volunteers aged 22 to 35 were included. A 4F tip transducer catheter was inserted under local anaesthesia into the radial artery up to the aortic arch. Intraarterial blood pressure was recorded before and during EECP. Blood pulse pressure, pulsatility index (ratio of peak pressure to end diastolic pressure) and standard deviation of blood pressure in 5 cardiac cycle was calculated to evaluate the pulsatility of arterial blood pressure. The results showed that blood pulse pressure, pulsatility index and standard deviation of blood pressure were elevated from 47 +/- 5 mmHg, 1.64 +/- 0.11 and 13.6 +/- 1.5 mmHg to 77 +/- 3 mmHg, 2.46 +/- 0.25 and 19.3 +/- 2.2 mmHg before and during EECP respectively (P < 0.05). Decreasing of systolic pressure and increasing of diastolic pressure during counterpulsation were also observed. EECP gives an elevation of pulsatility to human blood pressure.
Adult ; Blood Pressure ; physiology ; Blood Pressure Determination ; Counterpulsation ; Humans ; Male ; Pulsatile Flow

Pulsatile blood flow plays an important role in maintaining normal vascular endothelial function. Quantitative measurement of pulsatility of artery blood pressure and blood flow in dogs and effects of enhanced external counterpulsation (EECP) on the pulsatility were taken in this study. Common carotid artery blood pressure and blood flow were measured in 6 beagle dogs that had suffered from an acute myocardial infarction 6 weeks before. A 6F tip transducer catheter was inserted into the right common carotid artery to measure blood pressure, and blood flow was measured in the left common carotid artery by an electromagnetic blood flow probe under anesthesia before and during EECP. Blood pulse pressure, pulsatility index (ratio of peak pressure to end diastolic pressure) and standard deviation of blood pressure were calculated to evaluate the pulsatility of arterial blood pressure. Blood pulse flow, pulsatility index (ratio of peak flow to trough flow) and standard deviation of blood flow were calculated to evaluate the pulsatility of blood flow. Mean vascular resistance (MVR) was calculated as MVR = mean blood pressure/mean blood flow. Blood pulse pressure, pulsatility index and standard deviation of blood pressure were elevated from 30 +/- 9 mmHg, 1.26 +/- 0.05 and 8.7 +/- 2.5 mmHg to 43 +/- 8 mmHg (P < 0.05), 1.54 +/- 0.13 and 12.4 +/- 2.0 mmHg (P < 0.05) before and during EECP, respectively. Blood pulse flow, pulsatility index and standard deviation of blood flow were elevated from 317 +/- 48 ml/min, 2.85 +/- 0.21 and 96 +/- 21 ml/min to 447 +/- 88 ml/min, 4.56 +/- 0.90 and 131 +/- 39 ml/min before and during EECP (P < 0.05). MVR was decreased from 578 +/- 72 before EECP to 476 +/- 85 Wood units during EECP(P < 0.05). These data demonstrate that EECP gives an elevation of pulsatility to blood pressure and blood flow, thus it may lead to the decrease of vascular resistance.
Animals ; Blood Pressure ; Carotid Arteries ; physiology ; Counterpulsation ; Dogs ; Hemodynamics ; Pulsatile Flow ; Regional Blood Flow ; Vascular Resistance

OBJECTIVETo establish a pig model of chronic external counterpulsation.

METHODSTwelve pigs were anaesthetized with sodium pentobarbital (< or =30 mg/kg.b.w.) and 846 mixture (< or =0.1 ml/kg.b.w.) and counterpulsed in a lateral position for 2 h every two days (totally 36 h) with 0.025 to 0.04 MPa/cm(2) pressure.

RESULTSExternal counterpulsation was successfully completed in all the animals. Combined administration of sodium pentobarbital and 846 mixture resulted in good anesthetic effect with reduced anesthetic dosage and minimal side effect on the viscera (the liver, kidney and heart, etc).

CONCLUSIONThe pig model of chronic external counterpulsation has been successfully established. Combined use of sodium pentobarbital and 846 mixture is recommended for chronic external counterpulsation.

Anesthesia, General ; methods ; Animals ; Animals, Newborn ; Assisted Circulation ; Counterpulsation ; methods ; Models, Animal ; Pentobarbital ; administration & dosage ; Swine

OBJECTIVE: To investigate the effect of enhanced external counterpulsation (EECP) on plasma nitric oxide (NO), Endothelin 1 (ET1), high sensitive C-reactive protein (HSCRP) and quality of life (QoL) in patients with coronary artery disease (CAD). METHODS: We conducted a pilot randomized clinical trial in order to evaluate plasma NO, ET1, HSCRP and QoL before and after twenty sessions of EECP (group A) and cardiac rehabilitation (CR, group B) in 42 patients with CAD (21 in each group). RESULTS: Forty-two patients (33 male and 9 female) were included in the study. The mean age was 58.2+/-10 years. The mean HSCRP was 1.52+/-0.7 in the EECP group and it was reduced to 1.27+/-0.4 after intervention. The reduction in HSCRP was not statistically significant in EECP and CR groups with p=0.33 and p=0.27, respectively. There was not significant improvement of NO, ET1, and QoL in the EECP and CR groups shortly after therapy (p>0.05). CONCLUSION: Although the short-term EECP treatment in CAD patients improved HSCRP, NO, ET1, and QoL compared with the baseline those improvements are not statistically significant. Further studies are necessary with large study groups and more sessions.
C-Reactive Protein ; Coronary Artery Disease* ; Counterpulsation* ; Endothelin-1* ; Endothelins ; Humans ; Male ; Nitric Oxide* ; Pilot Projects* ; Plasma* ; Quality of Life* ; Rehabilitation*

Intraaortic balloon counterpulsation (IAB) has been shown to prolong survival in the critically ill cardiac patients. Originally developed for use in the patients with cardiogenic shock, the indications have been expanded. But despite technical advances, the complication rate associated with IAB remains high. The most commonly reported complications include damage to the femoral artery and distal embolization. Other reported major complications are balloon rupture, limb loss, bleeding, systemic infection and bowel infarction. We report a patient complicated by ischemic colitis causing stenosis and intestinal obstruction after IAB insertion.
Colitis, Ischemic* ; Constriction, Pathologic* ; Counterpulsation* ; Critical Illness ; Extremities ; Femoral Artery ; Hemorrhage ; Humans ; Infarction ; Intestinal Obstruction ; Rupture ; Shock, Cardiogenic

Intra-aortic ballon pump(IABP) has been widely used since 1968 when Kantrowitz reported its design and clinical application for the patient with cardiogenic shock. However, information regarding clinical effectiveness of this device in terms of hemodynamic status had been limited. Consequently, using a simple random sampling method we retrospectively selected 23( 65+/-9.7 yr, mean+/-S.D.) out of 223 cases in which IABP had been inserted for a period of 13 months (from September, 1986 through October, 1987) in Yale-New Haven Hospital and evaluated their hemodynamic parameters. Six of 23 cases had IABP inserted in the coronary care units(CCU) and 17 had undergone cardiopulmonary bypass(CPB) for coronary artery bypass graft(CABG) except one case for aneurysmectomy and VSD repair. Nine of these 17 had IABP inserted for improvement of their preoperative cardiovascular functions and eight of then for successful weaning from CPB following CABG. While the diastolic pressure, cardiac output and cardiac index(CI) had increased from 62+/-11.0mmHg, 4.4+/-1.40 I/min, and 2.5+/-0.80 I/min/m2 to 69+/-10.8, 5.1+/-1.34, and 2.8+/-0.83, respectively, pulmonary arterial diastolic pressure(PAD) and pulmonary capillary wedge pressure(PCWP) decreased from 22+/-9.7 and 19+/-4.9 to 20+/-4.5 and 16+/-5.9 mmHg, respectively, after IABP counterpulsation. Despite their poor preoperative hemodynamic function (ASA Class IV or V), 18 out of these 34 (78.3%) had survived during hospitalization. Under the condition of our study IABP appears to be an alternative beneficail therapeutic aid for the patient with cardiogenic shock.
Blood Pressure ; Capillaries ; Cardiac Output ; Coronary Artery Bypass ; Counterpulsation ; Hemodynamics* ; Hospitalization ; Humans ; Retrospective Studies ; Shock, Cardiogenic ; Weaning

Noise of ECP (external counterpulsation) comes from the frequent movement of the electromagnetic valve iron core hitting the top of the valve body and the orifice of the bottom, and the high pressure and large air stream rubbing the orifice. This article studies the method to reduce mechanical noise of the electromagnetic valve core, that is to reduce the above movement energy and the hitting force. The method is used in ECP devices with grafying results. This noise controlling technology may reduce the noise of the electromagnetic valve from higher than 50dB to less than 25dB.
Counterpulsation ; instrumentation ; Electromagnetic Phenomena ; instrumentation ; Electronics ; instrumentation ; Equipment Design ; Equipment Failure ; Humans ; Microcomputers ; Noise ; prevention & control ; Software

Electrocardiac signal is one of the most important signals which is used to trigger ventricular assist device (VAD), and the delay time of VAD assistance is very important to get a satisfied result. Proper delay will give VAD relatively enough time to assist, avoiding left heart failure caused by the collision of the heart and VAD during systolic phase. This becomes much more important when the left atrium drainage is insufficient. The aim of our study is to set up an equation to calculate the delay time by RR interval. We try to set up an equation about RR and R-Ao like: R-Ao = A x (RR)n + B(A and B are constant). RR represents the RR interval and R-Ao represents the duration of the period between the peak point of QRS and the point of aortic valve closing; First, calculate RR according to weighting average method, and then, calculate the anticipant R-Ao according to the before-mentioned equation. After adjustment, R-Ao will be used as assistance delay time. R-R interval was measured in 457 selected pediatric patients who were undergiong left heart catheterization and who did not have arrhythmias. From the ECG recording during catheterization, R-R interval was measured while R-Ao was obtained from aortic pressure wave chart; Plot graphs with R-Ao as dependent variable and (RR)n as independent variable; find out correlating model and calculate the arguments A and B of R-Ao = A x (RR)n + B. The results showed that the relation between (RR)1/3 and R-Ao is the most significant, the relation coefficient is 0.733, the regress coefficient is -0.182 (P < 0.001) and the interception is 1.070. This means that R-Ao = (-0.182) (RR) 1/3 + 1.070. The likelyhood degrees of different sections differ markedly. When heart rate is less than 120 beats per min. The relation argument is about 0.733 while 0.45 when heart rate is more than 120 beats per min, Therefore, we can use the equation R-Ao = (-0.182) (RR)1/3 + 1.070 to calculate R-Ao when heart rate is less than 120 beats per min.
Adolescent ; Algorithms ; Child ; Child, Preschool ; Counterpulsation ; methods ; Electrocardiography ; Heart ; physiology ; Heart-Assist Devices ; Humans ; Signal Processing, Computer-Assisted

The development of external counterpulsation (ECP) local area network system and extensible markup language (XML)-based remote ECP medical information system conformable to digital imaging and communications in medicine (DICOM) standard has been improving the digital interchangeablity and sharability of ECP data. However, the therapy process of ECP is a continuous and longtime supervision which builds a mass of waveform data. In order to reduce the storage space and improve the transmission efficiency, the waveform data with the normative format of ECP data files have to be compressed. In this article, we introduced the compression arithmetic of template matching and improved quick fitting of linear approximation distance thresholding (LADT) in combimation with the characters of enhanced external counterpulsation (EECP) waveform signal. The DICOM standard is used as the storage and transmission standard to make our system compatible with hospital information system. According to the rules of transfer syntaxes, we defined private transfer syntax for one-dimensional compressed waveform data and stored EECP data into a DICOM file. Testing result indicates that the compressed and normative data can be correctly transmitted and displayed between EECP workstations in our EECP laboratory.
Computer Communication Networks ; standards ; Counterpulsation ; methods ; Humans ; Information Storage and Retrieval ; Medical Records Systems, Computerized ; standards ; Programming Languages