Home About us Contact
|
Home About us Contact | ||
|
|
||
Haemodynamic Profiles (haemodynamic + profile)
Selected AbstractsPredicting vascular access failure: A collective reviewNEPHROLOGY, Issue 4 2002Kevan R POLKINGHORNE SUMMARY: The maintenance of vascular access for haemodialysis contributes a large burden of morbidity and cost to any dialysis unit. Identifying vascular access at risk of thrombosis is an evolving and important aspect to the management of any haemodialysis patient. Haemodynamic profiles of native fistulas and arteriovenous grafts differ significantly, and, as such, the sensitivity of the specific monitoring techniques to detect dysfunction varies depending on access type. Multiple strategies are now available for monitoring vascular access including measuring intra-access pressure and access blood flow, or screening for significant stenoses with Doppler ultrasonography. the ability of each strategy to detect significant stenosis is reviewed by looking at the evidence for both arteriovenous fistula (AVF) and arteriovenous grafts (AVG), separately. the majority of published literature involves AVG, and measuring access blood flow is the modality of choice. the best method for measuring flow is not known. For AVF, much less is known, and it is not clear whether monitoring will decrease the thrombosis risk and prolong access life. Recommendations for AVF cannot be made until more evidence becomes available. [source] Measurement of cardiac output in normal pregnancy by a non-invasive two-dimensional independent Doppler deviceAUSTRALIAN AND NEW ZEALAND JOURNAL OF OBSTETRICS AND GYNAECOLOGY, Issue 2 2009Catharina C. M. KAGER Aims: To compose a normogram regarding cardiac output during pregnancy measured with ultrasonic cardiac output monitor (USCOM), a non-expensive simple continuous wave Doppler device and to investigate if this machine could be useful for haemodynamic monitoring during pregnancy. Methods: Cardiac output was measured in 172 pregnant women with a gestational age < 21 weeks (n = 59), 21,32 weeks (n = 48), and > 32 weeks' gestation (n = 48). Interobserver differences were determined by measuring 24 patients and comparing results between three different observers. Results: A good signal could be obtained in 155 (90.2%) pregnant women. Haemodynamic profiles were in line with data published in the literature. In 9.8 % of cases it was difficult to get a good result. Interobserver variations between the research officer (CK) and two clinicians were good (r = 0.9359 and r = 0.9609). Conclusion: USCOM appears to be a reliable and fast method to measure cardiac output compared with existing highly complex ultrasounds machines used in cardiology. It is easy to learn, cheap and quite reproducible between different observers. Further research is required to define its place in the management of hypertensive complications during pregnancy. [source] The effects of obstructive jaundice on the pharmacodynamics of propofol: does the sensitivity of intravenous anesthetics change among icteric patients?ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 10 2009J. C. SONG Background Some studies suggest that certain clinical symptoms of cholestasis, such as fatigue and pruritus, result from altered neurotransmission. Patients with obstructive jaundice also have labile blood pressure and heart rate. In the present study, the authors investigated whether obstructive jaundice affects a patient's sensitivity to hypnotics and the haemodynamic profile of propofol. Methods Thirty-six ASA physical status I/II/III patients with serum total bilirubin (TBL) from 7.8 to 362.7 ,mol/l scheduled for bile duct surgery were recruited. A computer-controlled propofol infusion programmed for effect site target was used to rapidly attain and maintain sequential increase of the compartment concentration (from 1 to 3 ,g/ml). Each target-controlled concentration was maintained for about 12 min, and arterial blood samples were drawn for propofol concentration determination. The bispectral index (BIS) and mean arterial pressures (MAP) were used as indices of the propofol effect. The relation between the concentration and the effects was described by the Hill equation. The pharmacodynamic parameters were optimized using a nonlinear mixed-effect model. Results TBL was not a significant covariate of EC50 for the pharmacodynamic model. For BIS and MAP, the parameters of the pharmacodynamic model were Emax=75.77%, EC50=2.34 ,g/ml, and ,=1.82, and Emax=47.83%, EC50=1.49 ,g/ml, and ,=1.88, respectively. Conclusions We demonstrated that obstructive jaundice with serum TBL from 7.8 to 362.7 ,mol/l had no effect on propofol pharmacodynamics observed by BIS and MAP. [source] Relevance of the C-terminal Arg-Phe sequence in ,2 -melanocyte-stimulating hormone (,2 -MSH) for inducing cardiovascular effects in conscious ratsBRITISH JOURNAL OF PHARMACOLOGY, Issue 7 2000M J M A Nijsen The cardiovascular effects by ,2 -melanocyte-stimulating hormone (,2 -MSH) are probably not due to any of the well-known melanocortin subtype receptors. We hypothesize that the receptor for Phe-Met-Arg-Phe-amide (FMRFa) or Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-amide (neuropeptide FF; NPFFa), other Arg-Phe containing peptides, is the candidate receptor. Therefore, we studied various Arg-Phe containing peptides to compare their haemodynamic profile with that of ,2 -MSH(6,12), the most potent fragment of ,2 -MSH. Mean arterial pressure (MAP) and heart rate (HR) changes were measured in conscious rats after intravenous administration of ,2 -MSH related peptides. Phe-Arg-Trp-Asp-Arg-Phe-Gly (,2 -MSH(6,12)), FMRFa, NPFFa, Met-enkephalin-Arg-Phe-amide (MERFa), Arg-Phe-amide (RFa), acetyl-Phe-norLeu-Arg-Phe-amide (acFnLRFa) and desamino-Tyr-Phe-norLeu-Arg-Phe-amide (daYFnLRFa) caused a dose-dependent increase in MAP and HR. ,2 -MSH(6,12) showed the most potent cardiovascular effects (ED50=12 nmol kg,1 for ,MAP; 7 nmol kg,1 for ,HR), as compared to the other Arg-Phe containing peptides (ED50=177,292 nmol kg,1 for ,MAP; 130,260 nmol kg,1 for ,HR). Peptides, which lack the C-terminal Arg-Phe sequence (Lys-Tyr-Val-Met-Gly-His-Phe-Arg-Trp-Asp-Arg-Pro-Gly (,2 -pro11 -MSH), desamino-Tyr-Phe-norLeu-Arg-[L-1,2,3,4 tetrahydroisoquinoline-3-carboxylic acid]-amide (daYFnLR[TIC]a) and Met-enkephalin (ME)), were devoid of cardiovascular actions. The results indicate that the baroreceptor reflex-mediated reduction of tonic sympathetic activity due to pressor effects is inhibited by ,2 -MSH(6,12) and that its cardiovascular effects are dependent on the presence of a C-terminal Arg-Phe sequence. It is suggested that the FMRFa/NPFFa receptor is the likely candidate receptor, involved in these cardiovascular effects. British Journal of Pharmacology (2000) 131, 1468,1474; doi:10.1038/sj.bjp.0703709 [source] Regional haemodynamic effects of cyclosporine A, tacrolimus and sirolimus in conscious ratsBRITISH JOURNAL OF PHARMACOLOGY, Issue 4 2004S M Gardiner The observation that the immunosuppressants, cyclosporine A (CsA) and tacrolimus, have pressor effects, but sirolimus does not, has led to an hypothesis that generalised sympathoexcitation, resulting from inhibition of calcineurin by CsA and tacrolimus underlies their pressor effects, because sirolimus does not inhibit calcineurin. It is unknown if sirolimus has haemodynamic actions not accompanied by a pressor effect, and whether or not the pressor effects of CsA and tacrolimus are accompanied by similar haemodynamic changes. Therefore, the first aim of our studies was to investigate these possibilities in conscious, chronically-instrumented, male, Sprague-Dawley rats. CsA (5.9 mg kg,1 bolus i.v.) caused rapid-onset, prolonged hypertension, tachycardia and mesenteric vasoconstriction. There was a slower onset renal vasoconstriction, but no significant change in hindquarters vascular conductance; all the effects of CsA were significantly greater than those of vehicle. CsA given by infusion (over 30 min or 2 h) caused changes qualitatively similar to those above. Repeated administration of CsA over 4 days did not enhance its cardiovascular effects. Pretreatment with the angiotensin (AT1) receptor antagonist, losartan, and the endothelin (ETA and ETB) receptor antagonist, SB 209670, reduced the pressor and mesenteric vasoconstrictor effects of CsA. Additional administration of the , -adrenoceptor antagonist, phentolamine, completely inhibited the cardiovascular effects of CsA. Tacrolimus (450 ,g kg,1 bolus i.v.) caused similar peak pressor and tachycardic effects to CsA, but these were much slower in onset, and were maximal when there were no significant regional vasoconstrictions, indicating that the pressor effect was probably due to a rise in cardiac output. However, although propranolol reversed the tachycardic effect of tacrolimus, it did not influence the pressor response. Sirolimus (450 ,g kg,1 bolus i.v.) had no tachycardic action, and only a modest, transient pressor effect, accompanied by equally brief reductions in renal, mesenteric, and hindquarters vascular conductances. The differences between the regional haemodynamic profiles of equipressor doses of CsA and tacrolimus, and the finding that sirolimus has significant cardiovascular actions, indicate that generalised sympathoexcitation, resulting from calcineurin inhibition (with CsA and tacrolimus), is unlikely to be the sole explanation of their pressor effects. British Journal of Pharmacology (2004) 141, 634,643. doi:10.1038/sj.bjp.0705659 [source] | ||||||||||