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At least 415 records · Page 23Linked to original sources
PubMed1992

Hypertrophic scar: an interruption in the remodeling of repair--a laser Doppler blood flow study.

Soft-tissue dermal loss does not regenerate; instead, it is replaced with scar. The extent of scarring is directly related to the severity of tissue loss (in terms of volume and depth). Commonly, an acute dermal loss will heal with excessive scar, hypertrophic scar. A hypertrophic scar is elevated but is contained within the boundaries of the initial injury. Hypertrophic scars have a reddish appearance, indicating an elevated local circulation. A laser Doppler blood flow monitor was employed to measure blood flow changes in healed wounds. It was speculated that local circulation in a developing hypertrophic scar would be elevated. Patients with recently healed wound sites were monitored and exhibited an average blood flow reading of 365 +/- 325 mV (n = 131). This average value, ranging from 98 to 1450 mV, was 18 times greater than the average reading from normal skin, which was 43 +/- 13 mV (n = 212). Blood flow declined to 32 +/- 21 mV (n = 7) at 16 to 18 weeks (74 percent of normal skin values) in healed wounds that developed normal scar. However, a closed wound that developed into a hypertrophic scar had a blood flow reading of 148 +/- 78 mV (n = 59) at 16 to 18 weeks. This value was three times greater than in normal skin and four times greater than in normal scar. At 38 to 50 weeks postinjury, hypertrophic scar remained elevated (102 +/- 34 mV; n = 10). Hypertrophic scars sustain an elevated blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Effects of the Berlin Heart biventricular assist device on microvascular responses in pre-transplant patients.

Microcirculatory forearm cutaneous blood flow was monitored continuously and noninvasively by laser doppler flow-metry (LDF) in 15 patients treated with the Berlin Heart biventricular assist device system (BVAD) for end-stage heart failure under stable hemodynamic states (BVAD pts, n = 10) and norepinephrine therapy (BVAD nor pts, n = 5). Ten healthy human subjects served as controls (C). Cutaneous blood flow was measured before, during, and after external brachial artery occlusion to evaluate the post-occlusive reactive hyperemia (PORH) as a standardized response. To examine microvascular responses to macrohemodynamic changes, the cardiac output (CO) was decreased by a 20% reduction in BVAD pump rate. No significant differences in baseline LDF measurements (in millivolts) were observed among the three groups (C, 470.7 mV +/- 177.3; BVAD pts, 328.0 mV +/- 122.7; BVAD nor pts, 360.0 mV +/- 160.0). After cuff pressure release (1 min later), a significant (p < 0.004) three-fold to four-fold blood flow increase (PORH) occurred in each group (C, 1113.6 mV +/- 469.2; BVAD pts, 813.0 mV +/- 190.1; BVAD nor pts, 498.0 mV +/- 191.8). The difference in PORH between the BVAD pts and BVAD nor pts was significant (p < 0.01), and the time to peak PORH values was different (p < 0.05) among the three groups (C, 22.2 s +/- 10.7; BVAD pts, 11.3 s +/- 12.5; BVAD nor pts, 7.0 s +/- 5.8). A markedly delayed return to baseline occurred in the BVAD pts. The 20% reduction in BVAD pump rate decreased CO significantly (p < 0.05) and increased (p < 0.01) systemic vascular resistance (SVR).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Cordocentesis and evaluation of fetal wellbeing in a very high-risk population (a very reliable index)].

In a population of 57 very high-risk pregnant women (severe clinical history and/or compromised fetus). A total of 240 tests for antepartum fetal evaluation were performed: baseline cardiotocography (CTG), biophysical profile scoring (BPS), doppler-velocimetry of umbilical artery and determination of blood gas analysis in venous umbilical cord blood obtained by cordocentesis. The results of the CTG, BPS, and umbilical artery doppler velocimetry showed a significant relation with those of pH and pO2. The sensitivity, specificity, false-abnormal value, and false-normal value of the CTG, PBS, and doppler velocimetry, used for the diagnosis of fetal acidosis, hypoxia, and asphyxia were comparable. The rate of fetal (asphyxia) was high if present severe/terminal CTG (85.0%), abnormal (4) BPS (82.0%), or absent-end diastole in umbilical artery doppler velocimetry (74.0%). The immediate complication rate due to cordocentesis procedure was minimal.

Acidosis↗
PubMed1991

[The blood rheological and microcirculatory changes in the hypertensive patient].

The authors examined the microcirculatory system alterations which are present in case of arterial hypertension. These alterations consist of an increase in capillary peripheral resistances and in total blood viscosity, of a reduction in red cell deformability and of a vasomotion alteration. The authors evaluated the opportunities of a therapeutic intervention with hypotensive treatments also affecting the microcirculatory system in hypertensive patients with or without associated diabetes mellitus.

Blood Viscosity↗
PubMed1991

[Vena caval flow patterns in patients with constrictive pericarditis: analysis by catheter-tip Doppler flowmetry].

Changes in superior and inferior vena caval flow patterns were analyzed in 5 patients with constrictive pericarditis and were compared with those of 10 normal control subjects. Caval flows were measured using catheter-tip Doppler flowmeters. The normal controls showed biphasic M-shaped flow patterns; the peaks of the first forward flow (S wave) and of the second forward flow (D wave) appeared coincident with mid-systole and mid-diastole, respectively. Reverse flows fell during the atrial contraction period (A wave) and late systole (V wave). In the normal controls, the ratios of the S wave to the D wave (S/D ratio) and the A wave to the S wave (A/S ratio) were 2.15 +/- 0.41 and 0.18 +/- 0.10, respectively, and there was a disproportionate respiratory variation in the S and D waves in the normal controls. In constrictive pericarditis, superior and inferior vena caval flow velocities were lower than those in the normal controls. The S/D and A/S ratios were 1.46 +/- 0.27 (p < 0.05 vs control) and 0.66 +/- 0.15 (p < 0.01 vs control), respectively, with the A wave increasing in proportion to the severity of constrictive pericarditis. In addition, there was only a minimal respiratory variation in constrictive pericarditis. In conclusion, recognition of the patterns of the superior and inferior vena caval flow velocities may be useful for diagnosing constrictive pericarditis.

Adult↗
PubMedDate not supplied

[Central and cerebral hemodynamics during general anesthesia in intracranial interventions in a sitting position].

Cerebral bloodflow and central hemodynamics were studied during general anesthesia in patients with tumors of the posterior cranial fossa operated on in a sitting posture. A sitting posture during general anesthesia is conductive to a marked reduction of the stroke volume and linear velocity of the cerebral bloodflow, this creating a risk of cerebral tissue ischemia under conditions of intracranial hypertension and a hardly adequate short-term compensatory increase of the total vascular resistance and "paradoxical" increase of cerebrovascular tone. Since the neurogenous mechanisms of cerebral bloodflow autoregulation are disordered during anesthesia, one should admit that stabilization of central hemodynamics at all stages of anesthesia is a most important condition for optimizing brain tissue perfusion.

Adult↗
PubMed1995

[Resistance index of anterior cerebral artery in the diagnosis of hypoxic ischemic encephalopathy in neonates].

OBJECTIVE: To study the relationship between the resistance index (RI) of the anterior cerebral artery and hypoxic ischemic encephapathy (HIE) in neonates for the purpose of finding out a method of diagnosing and predicting HIE and its prognosis. METHOD: The anterior cerebral artery blood flow velocity waveform (aCAFV) of neonates was recorded by a continuous Doppler technique and RI value was measured. 230 observations on 67 cases of high risk neonates and 534 on 182 normal neonates were performed. The mean value of RI and its standard deviation in normal neonates chosen served as control. The relationship between the standardized incidence of abnormal RI of the anterior cerebral artery and HIE was studied in high risk neonates. RESULT: In normal neonates (control group), RI was 0.62 +/- 0.09, and was in positive correlation (r = 0.72, P < 0.05) with the days after birth. The normal aCAFV was a regular waveform. In high risk neonates, the standardized incidence of abnormal RI in the neonates most likely to be attacked by HIE (A group) was significantly higher than that in control group (P < 0.001), but there was no significant difference between the other babies (B group) and control group (P > 0.05). However, the standardized incidence of abnormal RI in the A group was also significantly higher than that in the B group (P < 0.001). In the cases who were severely attacked by HIE, the standardized incidence of irregular waveform was the highest. Furthermore, when irregular aCAFV waveform appears, the incidence of pernicious complication of HIE and mortality of neonates were significantly increased in all cases. CONCLUSION: The abnormal RI value of anterior cerebral artery implies the existence of HIE in neonates. The prognosis is poor when irregular blood flow waveform appears.

Blood Flow Velocity↗
PubMed1995

[An experimental study of blood supply to the bile duct under arterio-portal shunting].

The aim of this study is to show whether arterio-portal shunting (APS) improves the blood supply to the bile duct (BD) subsequent to clamping of the arterial blood supply to the liver and the BD. A constant flow APS model was undertaken using beagles. The procedure involved arterio-portal shunting by performing a bypass from the femoral artery to the portal vein (PV) following clamping, assisted by a roller-pump. In one group (Clamp group: n = 6) the shunt flow was kept at 0 ml/min/kg resulting in a reduction in the tissue oxygen saturation level of the BD (%BDISO2) to 28%, and a reduction in the tissue blood flow of the BD (%BDBF) to 17%, of the pre-clamped values. The %BDISO2 and %BDBF were measured by a Tissue-Spectrophotometer and Laser Doppler Flowmeter, respectively. The %BDISO2 and %BDBF decreased rapidly and thereafter were constant. In the other group (Shunt group: n = 6) the shunt flow was kept at 14 ml/min/kg. An increase in the %BDISO2 and %BDBF to 57% and 47%, respectively, was observed. A flow-controlled APS model was also carried out (n = 6). It was found that by periodically increasing the shunt flow from 0 to 7, 14, and 28 ml/min/kg, the %BDISO2, %BDBF, PVSO2 (PV oxygen saturation), and PVF (PV flow) all gradually increased. Statistically, positive correlations were found between the %BDISO2 and PVSO2 (p < 0.0001) and the %BDBF and PVF (p = 0.0002). Twenty additional beagles were divided into a Control group (n = 9) and an APS group (n = 11). In the Control group, a choledochojejunostomy was performed. In the APS group however, in addition to a choledochojejunostomy, one end of the hepatic artery was anastomosed to the side of the PV following ligation of the common hepatic artery, the gastro-duodenal artery and the right gastric artery. The survival ratio, concentration levels of serum total bile acid, total bilirubin, ALP, LAP, and gamma GTP, as well as, histological findings were not significantly different between the Control and the APS group. This study indicates that the blood supply is significantly improved by APS accompanied by clamping of the arterial blood supply to the liver and the BD. This procedure would therefore be useful in the preservation of the bile duct's viability and the bilioenteroanastomosis in clinical practice.

Anastomosis, Surgical↗
PubMedDate not supplied

[The effect of degenerative cervical spine lesions and blood flow velocity in vertebrobasilar system in Doppler measurement].

The purpose of the study was to establish the effect of degenerative lesions of cervical vertebrae on blood flow velocity in the vertebrobasilar system measured by means of Doppler phenomenon using Transpect--TCD device according to generally accepted principles. The study was carried out in 20 healthy controls and 40 individuals with these lesions (aged 16-60 years). It was found that blood flow velocity in this arterial system is highly variable individually. In patients with degenerative changes pathological reduction of this velocity was found in this system which is an unquestionable evidence of the influence of these lesions on blood flow in vertebral arteries.

Adolescent↗
PubMed1995

Changes of motor evoked potentials in global and focal ischemic models of cats.

In order to evaluate the significance of motor evoked potentials (MEPs) in central nervous system monitoring, the authors conducted two sets of experiments using feline ischemic models. Twenty-three adult mongrel cats were divided into two groups: global (n = 9) and focal ischemic (n = 14) groups. In the case of global ischemia, which was induced by hypovolemic hypotension due to blood letting, deterioration of the D wave began when the mean arterial blood pressure (MABP) approached 45 mmHg, and regional cerebral blood flow (rCBF) dropped to 40% of control. Complete disappearance of the D wave was observed below 30 mmHg in MABP and 20% of control in rCBF. In the case of focal ischemia, which was induced by transorbital occlusion of the middle cerebral artery, the percentages of rCBF at which the D wave disappeared ranged from 9 to 20%. Changes in the amplitude of the D wave--an increase and following decrease--preceded the prolongation of its latency. In contrast with the D wave I waves were too easily affected by ischemia. Moreover, rCBF at the point of disappearance of the I wave varied greatly. In conclusion, the D wave is stable in mild ischemia and is a reliable indicator of critically profound ischemia (%rCBF < 40%). Monitoring the D wave of MEPs seems to be a useful method for avoiding the deterioration of motor function by ischemic insult.

Animals↗
PubMed1992

[Microcirculatory changes in mitral prolapse as an expression of a systemic change in the connective tissue].

Many authors hypothesize that mitral valve prolapse (MVP) can be, in most cases, only a clinical sign of a primitive and systemic disorder of the connective tissue, like in Marfan Syndrome (MS). In our previous works we supported the presence of morphological and functional alterations of the microcirculation in patients affected by MS. In order to characterize a possible common denominator between these pathologies we have studied the cutaneous microcirculation in a group of patients affected by MVP, divided into 2 groups: anatomic MVP (MVP) and MVP syndrome (MVPS). The morphologic parameters have been investigated by nailfold capillaroscopy while digital laser-Doppler was used to study skin flowmetry. The results have been compared with a control group. Capillaroscopic remarkers showed an architecturally disorganized microvasculature with aspects related to a reduced compactness of the microvasculature unit with a significatively higher score compared with controls (7.3 +/- 2.9 vs 3.6 +/- 1 p less than 0.0005). Laser-Doppler flowmetry showed a significatively reduced rest flow; ischemic test showed: spike time 48.9 +/- 36.9 vs 15.3 +/- 7.7 s (p less than 0.0005), hyperemic acme 6.6 +/- 2.7 vs 12.5 +/- 8.4 UP (p less than 0.002); % increase 32.1 +/- 20.2 vs 51.5 +/- 15.4 (p less than 0.002). Thermic test showed a significatively higher thermic acme 8.7 +/- 4.2 vs 12.6 +/- 9.11 UP (p less than 0.05). These results appeared to be correlated with stage pathology as it was observed a severe microvasculature disorders in MVPS. Therefore we suppose that a phenotypic continuum may exist between MS and MVP.

Adult↗
PubMed1982

Current status of noninvasive tests in the diagnosis of peripheral arterial disease.

In this review of the current status of the vascular laboratory, the major emphasis has been upon those tests that have become well-established and documented, including resting pressure, pulse volume measurements, velocity studies, and three stress measurements--exercise ankle pressure, postocclusive reactive hyperemia, and the toe pulse reappearance time. Additional technology that may have application to peripheral arterial disease includes photoplethysmography, transcutaneous oxygen tension, laser-Doppler velocimetry, fluorescein angiography, infrared thermography, and transcutaneous electromagnetic flowmetry. These techniques, which are currently in development and experimental trial, were not discussed but are likely to provide significant additional information. The future role of the vascular diagnostic laboratory in the area of peripheral arterial occlusive disease appears clear. It has already become a standard resource of the community hospital and tertiary referral center. Its functions will become more and more generally accepted with time as newly graduating physicians who have been exposed to this technology enter the practice of medicine. It should permit obtaining an evaluation of all patients at the expert level, aid in the education of all physicians concerned with peripheral arterial disease, and play an important part in guaranteeing a higher level of patient care than has heretofore been available.

Arterial Occlusive Diseases↗
PubMed1988

Partitional measurement of capillary and arteriovenous anastomotic blood flow in the human finger by laser-Doppler-flowmeter.

This study was made to see whether changes in blood flow through the capillaries and arteriovenous anastomoses (AVA's) of the human finger can be measured by noninvasive flowmetry. Total finger blood flow (FBF) was measured by venous occlusion plethysmography; blood flow was measured by a laser-Doppler flowmeter (ADVANCE, ALF-2100, Tokyo, Japan) using probes with optic fiber separations of 0.3 mm (LDF-0.3) and 0.7 mm (LDF-0.7). The maximum sensitivities for LDF-0.3 and LDF-0.7 were at depths of 0.8 and 1.2 mm from the tissue surface respectively. Two series of experiments were performed on separate days. In the first series the test hand was immersed in a water bath whose temperature (Tw) was 25 degrees C at an ambient temperature (Ta) of 25 degrees C. Tw was raised to 35 degrees C (local hand warming), which was then followed by an increase in Ta to 35 degrees C (whole body warming). FBF, LDF-0.3, and LDF-0.7 increased during these thermal stimulations. However, the relationship of FBF to LDF-0.3 showed two different regression lines. In contrast, the relationship of FBF to LDF-0.7 showed a single regression line. In the second series, with Ta at 35 degrees C, the test hand was immersed in a water bath at Tw 35 degrees C. Tw was then raised every 10 min by 2 degrees C steps from 35 to 41 degrees C. At Tw 39-41 degrees C, FBF and LDF-0.7 in the test hand were significantly decreased compared with those at Tw 35 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗