Search results for "Vascular resistance"
showing 10 items of 130 documents
Changes in the adrenergic mechanisms of cerebral arteries after subarachnoid hemorrhage in goats.
1994
We have examined the effects of experimental subarachnoid hemorrhage (SAH), induced by delivering autologous blood into the subarachnoid space, on the adrenergic mechanisms of the goat cerebrovascular bed. To achieve this, the response to noradrenaline was recorded both in vivo, by measuring cerebral blood flow in unanesthetized animals, and in vitro, by recording isometric tension in isolated cerebral arteries. In addition, we checked the function of adrenergic innervation by measuring the tritium efflux evoked by electrical stimulation in cerebral arteries preloaded with [3H]-noradrenaline, and we examined this innervation by using both fluorescent and electron transmission microscopy. Al…
Normal Doppler Reference Values of the Pericallosal Artery
2015
Purpose: To provide the normal reference values of the Doppler flow of the pericallosal artery in relation to gestational age from 18 to 41 weeks of gestation. Materials and Methods: The pericallosal artery (PCA) was studied in 466 normal pregnancies. The pulsed Doppler evaluation of the pericallosal artery was done in A3 and A4 segments, and records from PI, RI and Vmax were studied. Results: The resistance index of the pericallosal artery in A3 / A4 segments exhibits a plateau from 18 to 31 weeks of gestation. After 31 weeks, a marked decrease becomes apparent. The pulsatility index of the pericallosal artery in A3 / A4 segments shows a plateau until 36 weeks of gestation. During the fina…
Pulmonale Thrombendarteriektomie bei thromboembolischer pulmonaler Hypertonie: Indikationen und Frühergebnisse
2008
Pulmonary thrombendarterectomy was performed in 32 patients (14 men and 18 women; mean age 38 +/- 15 years) with thromboembolic pulmonary hypertension (New York Heart Association stage III: n = 22; stage IV: n = 10). The preoperative arterial pO2 averaged 59 +/- 11 mm Hg; pulmonary vascular resistance (PVR) and mean pressure (MPAP) were increased to 1,045 +/- 430 dyn.s.cm-5 and 53 +/- 12 mm Hg, respectively. The perioperative death rate was 22% (7 of 32). In the 25 survivors the pulmonary hypertension was reduced to a PVR of 194 +/- 75 dys.s.cm-5, MPAP of 28 +/- 6 mm Hg. Subsequent re-examination in 15 patients (NYHA stage I: n = 14, stage II: n = 1) after a mean of 17 +/- 5 months demonstr…
Changes of Hemodynamic Parameters, Pulmonary Gas Exchange, and Extravascular Lung Water During Esophageal Cancer Surgery
1988
Esophagectomy is often connected to postoperative pulmonary complications with a high mortality rate [1, 3,4]. From 1980 to 1985 we treated 19 patients after esophagectomy in our intensive care unit. Nine patients (47%) died of pulmonary complications. From the literature [3] and from our own observations we came to the conclusion that the first pulmonary changes start during the operative procedure.
Chronische thromboembolische pulmonale Hypertonie: Hämodynamische Auswirkungen der selektiven Pulmonalis-DSA mit nicht-ionischem Kontrastmittel
1998
PURPOSE This study evaluates the effects of pulmonary bolus injection of nonionic contrast medium on pulmonary artery pressure and resistance in patients with chronic thromboembolic pulmonary hypertension. METHODS In 39 patients (age 52 +/- 15) haemodynamic measurements were performed during bolus injection of nonionic contrast medium in a control group (I), in moderately severe (II) and severe pulmonary hypertension (III). RESULTS Initial inspiratory arrest caused significant pressure increase in all groups prior to bolus injection (delta PAsyst: 7.1 +/- 6.7 [I], 6.8 +/- 3.9 [II] und 7.2 +/- 7.9 mmHg p < 0.05). However, contrast bolus injection (25.1 +/- 2.3 ml iopamidol, 13.0 ml/s) caused…
Effects of Tolazoline and Prostacyclin on Pulmonary Hypertension in Infants After Cardiac Surgery
1992
Objective To evaluate the hemodynamic effects of tolazoline and prostacyclin in infants with pulmonary vasospasm after cardiac surgery. Design Prospective cohort study. Setting Pediatric ICU. Patients The cohort consisted of 42 infants and children with congenital heart disease and pulmonary hypertension who underwent corrective surgery and were monitored postoperatively using pulmonary artery catheters. Fourteen infants (2 to 12 months old) in this group required postoperative treatment with tolazoline or prostacyclin. Interventions Tolazoline was administered as a bolus of 0.5 mg/kg for treatment of persistent pulmonary hypertension or acute pulmonary hypertensive crisis. If its effective…
Interleukin-32 in systemic sclerosis, a potential new biomarker for pulmonary arterial hypertension
2020
Abstract Background Pulmonary arterial hypertension (PAH) is a severe complication of systemic sclerosis (SSc), associated with a progressive elevation in pulmonary vascular resistance and subsequent right heart failure and death. Due to unspecific symptoms, the diagnosis of PAH is often delayed. On this basis, it is of great value to improve current diagnostic methods and develop new strategies for evaluating patients with suspected PAH. Interleukin-32 (IL-32) is a proinflammatory cytokine expressed in damaged vascular cells, and the present study aimed to assess if this cytokine could be a new biomarker of PAH during SSc. Methods The IL-32 expression was evaluated in the sera and skin sam…
Thrombendarteriektomie bei chronischer thromboembolischer pulmonaler Hypertonie: Hämodynamik und Rechtsherzfunktion im Langzeitverlauf
2008
OBJECTIVE To find out whether pulmonary thromboendarterectomy (PTE) can achieve lasting reduction of pulmonary vascular resistance in patients with pulmonary arterial hypertension due to chronic thromboembolism. PATIENTS AND METHODS 45 patients (25 women, 20 men; mean age 45 +/- 24 [19-67] years) were re-investigated a mean of 21 (13-32) months after successful PTE. Two patients had then been in New York Heart Association (NYHA) stage II, 26 in stage III, and 17 in stage IV. In addition to clinical examination and chest radiogram 36 patients had right heart catheterization, 28 pulmonary angiography and 44 echocardiography. RESULTS Definite improvement of symptoms had occurred in all. 34 wer…
The Effects of Epinine on Arterial Blood Pressure and Regional Vascular Resistances in Anesthetized Rats
1998
1. We carried out experiments in anesthetized rats to study the hemodynamic effects of intravenous injections of epinine. 2. Epinine (1-320 micrograms/kg) produced a biphasic effect on mean arterial blood pressure (n = 30). At doses lower than 40 micrograms/kg, arterial blood pressure decreased (by as much as 21.5 +/- 3.4%), though at higher doses it increased dose dependently (by as much as 73.2 +/- 14.5%). Epinine also produced bradicardia in a dose-dependent manner (by as much as 26.4 +/- 4.9%). Sulpiride (100 micrograms/kg) suppressed the hypotensive effect of epinine but did not change the hypertensive effect. In the presence of prazosin (1,000 micrograms/kg), arterial blood pressure r…
Dilation of the ductus venosus by stent implantation increases placental blood perfusion in fetal sheep.
2006
The reduction of resistance to flow in the ductus venous (DV) and a decrease of blood supply to the liver serve for the survival of the fetus during hypoxia. The present study investigated the influence of the increased diameter of the DV on placental blood perfusion.In 15 ewes with twin pregnancies at gestational ages of 117 +/- 4 days, a stent (4 or 5 mm) was placed into the DV of 1 twin (DV(stent) group) under ultrasound guidance. Blood flow rates in the umbilical vein (UV) and DV of both fetuses were measured using Doppler ultrasound. Eight pairs of twin fetuses were included for the final analysis.The dilatation of the DV increased the blood flow volume rate passed through the DV from …