Acute Disease ; Animals ; Female ; Hypoxia ; physiopathology ; Male ; Microcirculation ; physiology ; Rats ; Splanchnic Circulation ; physiology ; Superoxide Dismutase ; blood

The incidence of cerebral palsy has not decreased despite advances in neonatal care. Preterm infants are at a high risk of cerebral palsy. Moreover, preterm infants might experience permanent neurological sequelae due to injury in the preterm brain. Although the etiology of preterm brain injury is not fully understood, preterm brain injury is strongly associated with abnormal cerebral perfusion and oxygenation. Monitoring systemic blood pressure or arterial oxygen saturation using pulse oximetry is not enough to guarantee proper cerebral perfusion or oxygenation. Early detection of improper cerebral perfusion can prevent irreversible cerebral damage. To decrease brain injury through the early detection of under-perfusion and deoxygenation, other diagnostic modalities are needed. Near-infrared spectroscopy can continuously and noninvasively monitor regional oxygen saturation (rSO₂), which reflects the perfusion and oxygenation status of tissues at bedside. Near-infrared spectroscopy represents a balance between tissue oxygen supply and demand. Cerebral rSO₂ monitoring has been used most frequently in neonatal cardiac surgery to monitor cerebral oxygenation and prevent hypoxic damage or shock. Recently, cerebral, renal, or splanchnic rSO₂ in neonates is frequently monitored. The progression of a disease, brain injury, and death can be prevented by detecting changes in rSO₂ values using near-infrared spectroscopy. In this article, the basic principles, usefulness, and applications of near-infrared spectroscopy in neonates are discussed.
Blood Pressure ; Brain ; Brain Injuries ; Cerebral Palsy ; Cerebrovascular Circulation ; Humans ; Incidence ; Infant, Newborn ; Infant, Premature ; Oximetry ; Oxygen ; Perfusion ; Shock ; Spectroscopy, Near-Infrared ; Splanchnic Circulation ; Thoracic Surgery

No abstract available.
Aortic Coarctation/complications/physiopathology/*ultrasonography ; Aortography/methods ; Collateral Circulation ; Humans ; Hypertension/etiology/physiopathology/*ultrasonography ; Male ; Predictive Value of Tests ; Regional Blood Flow ; Renal Artery/physiopathology/*ultrasonography ; *Renal Circulation ; Tomography, X-Ray Computed ; *Ultrasonography, Doppler ; Young Adult

Animals ; Extremities ; blood supply ; Heparin ; pharmacology ; Male ; Mesentery ; blood supply ; Microcirculation ; drug effects ; Rats ; Rats, Wistar ; Reperfusion Injury ; Splanchnic Circulation ; drug effects

Autologous red blood cells (RBC) labeled with fluorescence were immitted into microvessel of SD rat and observed under microscope. The movement of each individual labeled RBC was recorded by microscope video camera system. The recorded videotape is replayed to sample dark background fluorescent images through frame grabber. Sampled frame images were separated into odd and even field sequence images. Then these sequence images were analyzed to get the flow rate. The error between the actual flow velocity value and the flow velocity value of fluorescent globules in the chamber measured under the same system was below 7%. The upper limit was 9.6 mm/s. There are no obvious differences (P > 0.05). This system has been applied in the research of rat microcirculatory disturbance, and the temporal flow rate change in microvessel was obtained.
Animals ; Blood Flow Velocity ; physiology ; Image Processing, Computer-Assisted ; Microcirculation ; physiology ; Microscopy, Fluorescence ; Rats ; Rats, Sprague-Dawley ; Splanchnic Circulation ; physiology ; Videotape Recording

OBJECTIVETo analyze the correlation between pressure-derived collateral coronary flow (PDCF) and Rentrop grade of patients with acute myocardial infarction (AMI).

METHODSPDCF, determined by the ratio of P(w)/P(a), was measured in 29 patients with AMI of the first onset who received primary percutaneous coronary intervention (PCI) within 12 h after the onset. Sufficient collateral flow (group A, n=19) was defined as PDCF>0.24 and insufficient collateral flow (group B, n=10) as PDCF< or =0.24. Rentrop grade of the collateral flow was evaluated by coronary angiography. Echocardiography was performed on the 3rd and 30th day after PCI. The left ventricular ejection fraction, end-systolic and end-diastolic volumes, and the related indexes were obtained.

RESULTRentrop grade was significantly related to PDCF (r=0.75, P<0.01), but a wide range of PDCF was observed in patients with Rentrop grade< or =1.

CONCLUSIONPDCF measurement allows quantitative evaluation of the collateral flow in patients with AMI.

Adult ; Aged ; Angioplasty, Balloon, Coronary ; Blood Pressure ; physiology ; Collateral Circulation ; physiology ; Coronary Angiography ; methods ; Coronary Circulation ; physiology ; Female ; Humans ; Male ; Middle Aged ; Myocardial Infarction ; diagnostic imaging ; physiopathology ; therapy ; Neovascularization, Physiologic ; Regional Blood Flow

Utilizing the third-order polynomial curve fitted to the experimental data, which represents the relationship between cerebral blood flow (CBF) and mean artery blood pressure (MABP), we constructed a lumped-parameter dynamic model with 5 elements. In this model; the resistance is not constants it is determined by the fitted curve. We simulated the process of CBF autoregulation numerically by solving the govern equation of this model and got quite accurate results. Furthermore, we studied the influence of hemodynamic parameters on the CBF autoregulation by this model and proved that the characteristic resistance is the most important factor.
Blood Flow Velocity ; Blood Pressure ; physiology ; Cerebrovascular Circulation ; physiology ; Homeostasis ; Humans ; Hypotension ; physiopathology ; Models, Biological ; Oxygen ; metabolism ; Regional Blood Flow

OBJECTIVETo evaluate the changes of cerebral blood flow (CBF) with real-time contrast-enhanced ultrasound (CEU) in a canine model of acute cerebral ischemia.

METHODSCerebral perfusion was assessed in 6 dogs subjected to craniotomy with CEU at the time of 0, 30, 60, 90 and 120 min after occlusion of the left common carotid artery (LCCA). The microvascular volume (A) and blood flow velocity (beta) in the brain were measured from the time-versus-acoustic intensity plots, and the value of Axbeta were calculated. 99mTc-ECD brain single photon emission computed tomography (SPECT) was performed on the day before the experiment and at 120 min after LCCA occlusion. The radioactive counts on both sides of the cerebral cortex were calculated.

RESULTSA significant correlation was found between Axbeta from CEU and volume of the blood flow of the CCA from Doppler flowmetry. A, beta and Axbeta values varied significantly between the different time points (P>0.001). The ipsilateral hemisphere showed a low-perfusion state while the contralateral hemisphere showed a high-perfusion state immediately after the occlusion.

CONCLUSIONSThe changes of beta is the main regulation mechanism during acute cerebral ischemia in dogs.

Animals ; Blood Flow Velocity ; Brain ; blood supply ; Brain Ischemia ; diagnostic imaging ; Cerebrovascular Circulation ; Dogs ; Male ; Regional Blood Flow ; Ultrasonography

The current emphasis on the acquisition of physiological data by noninvasive means for mass medical screening and patient monitoring has increased interest in the use of electrical impedance for the measurement of physiological events. The technique has gained some degree of acceptance for monitoring respiration (Baker and Geddes, 1970), and much interest has been displayed recently in use of the technique to measure cardiac output including studies by Kubicek et al. (1966) Judy et al. (1969), and Mohapatra (1981). Other applications using the impedance technique include thoracic fluid accumulation, peripheral blood flow, cerebral blood flow, muscle contraction, eye movement, and uterine contraction, etc. The purpose of this article is to introduce the various impedance techniques for the measurement of physiological variables.
Cardiography, Impedance ; Cerebrovascular Circulation ; Extremities/blood supply ; Female ; Human ; *Plethysmography, Impedance ; Regional Blood Flow ; Respiration ; Uterine Contraction

BACKGROUND: Pulsatile pumps for extracorporeal circulation have been known to be better for tissue perfusion than non-pulsatile pumps but be detrimental to blood corpuscles. This study is intended to examine the risks and benefits of T-PLS(TM) through the comparison of clinical effects of T-PLS(TM) (pulsatile pump) and Bio-pump(TM) (non-pulsatile pump) used for coronary bypass surgery. MATERIAL AND METHOD: The comparison was made on 40 patients who had coronary bypass using T-PLS(TM) and Bio-pump(TM) (20 patients for each) from April 2003 to June 2005. All of the surgeries were operated on pump beating coronary artery bypass graft using cardiopulmonary extra-corporeal circulation. Risk factors before surgery and the condition during surgery and the results were compared. RESULT: There was no significant difference in age, gender ratio, and risk factors before surgery such as history of diabetes, hypertension, smoking, obstructive pulmonary disease, coronary infarction, and renal failure between the two groups. Surgery duration, hours of heart-lung machine operation, used shunt and grafted coronary branch were little different between the two groups. The two groups had a similar level of systolic arterial pressure, diastolic arterial pressure and mean arterial pressure, but pulse pressure was measured higher in the group with T-PLS(TM) (46+/-15 mmHg in T-PLS(TM) vs 35+/-13 mmHg in Bio-pump(TM), p<0.05). The T-PLS(TM)-operated patients tended to produce more urine volume during surgery, but the difference was not statistically significant (9.7+/-3.9 cc/min in T-PLS(TM) vs 8.9+/-3.6 cc/min in Bio-pump(TM), p=0.20). There was no significant difference in mean duration of respirator usage and 24-hour blood loss after surgery between the two groups. Plasma free Hb was measured lower in the group with T-PLS(TM) (24.5+/-21.7 mg/dL in T-PLS(TM) versus 46.8+/-23.0 mg/dL in Bio-pump(TM), p<0.05). There was no significant difference in coronary infarction, arrhythmia, renal failure and morbidity rate of cerebrovascular disease. There was a case of death after surgery (death rate of 5%) in the group tested with T-PLS(TM), but the death rate was not statistically significant. CONCLUSION: Coronary bypass was operated with T-PLS(TM) (Pulsatile flow pump) using a heart-lung machine. There was no unexpected event caused by mechanical error during surgery, and the clinical process of the surgery was the same as the surgery for which Bio-pump(TM) was used. In addition, T-PLS(TM) used surgery was found to be less detrimental to blood corpuscles than the pulsatile flow has been known to be. Authors of this study could confirm the safety of T-PLS(TM).
Arrhythmias, Cardiac ; Arterial Pressure ; Blood Cells ; Blood Pressure ; Cardiopulmonary Bypass ; Coronary Artery Bypass ; Extracorporeal Circulation ; Heart-Lung Machine ; Humans ; Hypertension ; Infarction ; Lung Diseases, Obstructive ; Mortality ; Perfusion* ; Plasma ; Pulsatile Flow ; Renal Insufficiency ; Risk Assessment ; Risk Factors ; Smoke ; Smoking ; Transplants ; Ventilators, Mechanical