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Volume Relationship (volume + relationship)
Selected AbstractsEffects of acute hyperglycaemia on anorectal motor and sensory function in diabetes mellitusDIABETIC MEDICINE, Issue 2 2004A. Russo Abstract Aims To determine the effects of acute hyperglycaemia on anorectal motor and sensory function in patients with diabetes mellitus. Methods In eight patients with Type 1, and 10 patients with Type 2 diabetes anorectal motility and sensation were evaluated on separate days while the blood glucose concentration was stabilized at either 5 mmol/l or 12 mmol/l using a glucose clamp technique. Eight healthy subjects were studied under euglycaemic conditions. Anorectal motor and sensory function was evaluated using a sleeve/sidehole catheter, incorporating a barostat bag. Results In diabetic subjects hyperglycaemia was associated with reductions in maximal (P < 0.05) and plateau (P < 0.05) anal squeeze pressures and the rectal pressure/volume relationship (compliance) during barostat distension (P < 0.01). Hyperglycaemia had no effect on the perception of rectal distension. Apart from a reduction in rectal compliance (P < 0.01) and a trend (P = 0.06) for an increased number of spontaneous anal sphincter relaxations, there were no differences between the patients studied during euglycaemia when compared with healthy subjects. Conclusions In patients with diabetes, acute hyperglycaemia inhibits external anal sphincter function and decreases rectal compliance, potentially increasing the risk of faecal incontinence. Diabet. Med. 21, 176,182 (2004) [source] Single-beat estimation of the left ventricular end-systolic pressure,volume relationship in patients with heart failureACTA PHYSIOLOGICA, Issue 1 2010E. A. Ten Brinke Abstract Aim:, The end-systolic pressure,volume relationship (ESPVR) constructed from multiple pressure,volume (PV) loops acquired during load intervention is an established method to asses left ventricular (LV) contractility. We tested the accuracy of simplified single-beat (SB) ESPVR estimation in patients with severe heart failure. Methods:, Nineteen heart failure patients (NYHA III-IV) scheduled for surgical ventricular restoration and/or restrictive mitral annuloplasty and 12 patients with normal LV function scheduled for coronary artery bypass grafting were included. PV signals were obtained before and after cardiac surgery by pressure-conductance catheters and gradual pre-load reductions by vena cava occlusion (VCO). The SB method was applied to the first beat of the VCO run. Accuracy was quantified by the root-mean-square-error (RMSE) between ESPVRSB and gold-standard ESPVRVCO. In addition, we compared slopes (EES) and intercepts (end-systolic volume at multiple pressure levels (70,100 mmHg: ESV70,ESV100) of ESPVRSB vs. ESPVRVCO by Bland,Altman analyses. Results:, RMSE was 1.7 ± 1.0 mmHg and was not significantly different between groups and not dependent on end-diastolic volume, indicating equal, high accuracy over a wide volume range. SB-predicted EES had a bias of ,0.39 mmHg mL,1 and limits of agreement (LoA) ,2.0 to +1.2 mmHg mL,1. SB-predicted ESVs at each pressure level showed small bias (range: ,10.8 to +9.4 mL) and narrow LoA. Two-way anova indicated that differences between groups were not dependent on the method. Conclusion:, Our findings, obtained in hearts spanning a wide range of sizes and conditions, support the use of the SB method. This method ultimately facilitates less invasive ESPVR estimation, particularly when coupled with emerging noninvasive techniques to measure LV pressures and volumes. [source] Impact of Left Ventricular Function on the Pulmonary Vein Doppler Spectrum:ECHOCARDIOGRAPHY, Issue 1 2003Nonsimultaneous Assessment with Load-Insensitive Indices Pulmonary vein Doppler spectrum is highly load-dependent and thus has been used to estimate left ventricular (LV) filling pressure. However, the impact of LV function on pulmonary vein Doppler spectrum remains obscure because only load-sensitive indices were studied previously. In the present study, measurements of the pulmonary vein Doppler spectrum were correlated with load-insensitive LV systolic (end-systolic elastance [Ees]) and diastolic (relaxation time constant [tau] and beta coefficient of the end-diastolic pressure volume relationship) function indices obtained from an invasive catheterization study nonsimultaneously. The peak velocity, velocity time integral, and duration of systolic forward spectrum were significantly correlated with Ees (r = 0.35, r = 0.36, andr = 0.41, respectively;P < 0.05). The pulmonary vein diastolic velocity time integral (PVDVTI) and duration of the diastolic forward spectrum were significantly correlated with Ees (r = 0.51andr = 0.57, respectively;P < 0.01). PVDVTI was correlated with tau and the end-diastolic pressure-volume relationship (EDPVR) (r = 0.42andr = 0.40respectively,P < 0.05). On the other hand, the systolic fraction of the forward spectrum was significantly correlated with ejection fraction (for peak velocity,r = 0.63, P < 0.01; for velocity time integral,r = 0.37, P < 0.05) but not with Ees, and the diastolic fraction of the forward spectrum was significantly correlated with minimum pressure derivative over time (for peak velocity,r = 0.48, P < 0.05; for velocity time integral,r = 0.44, P < 0.05, respectively) but not with tau or EDPVR. In summary, the systolic and diastolic components of the pulmonary vein Doppler spectrum are affected variably by LV systolic and diastolic function, independent of the loading condition. The systolic and diastolic fraction of pulmonary vein Doppler spectrum appears to depend more on the loading condition than the LV systolic or diastolic function. (ECHOCARDIOGRAPHY, Volume 20, January 2003) [source] Fluid challenge in patients at risk for fluid loading-induced pulmonary edemaACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 1 2004M. Matejovic Background:, This study evaluated the effects of protocol-guided fluid loading on extravascular lung water (EVLW) and hemodynamics in a group of patients at high risk for volume expansion-induced pulmonary and systemic edema. Methods:, Nine acutely admitted septic patients with acute lung injury (ALI) were prospectively studied. In addition to sepsis and ALI, the following criteria indicating increased risk for edema formation had to be fulfilled: increased vascular permeability defined as microalbuminuria greater than fivefold normal and hypoalbuminemia <30 g l,1. Two hundred-ml boluses of a 10% hydroxyethyl starch (HES) was titrated to obtain best filling pressure/stroke volume relation. Extravascular lung water and intrathoracic blood volume (ITBV) were measured using a transpulmonary double-indicator dilution technique. Baseline data were compared with data at the end of fluid loading and 3 h postchallenge. Results:, At study entry the mean EVLW was 13 ml kg,1, and the mean EVLW/ITBV ratio (indicator of pulmonary permeability) was 0.72 (normal range 0.20,0.30). To attain optimal preload/stroke volume relation 633 ± 240 ml of HES was needed. Fluid loading significantly increased preload (CVP, PAOP and ITBV), and stroke volume. Effective pulmonary capillary pressure (Pcap) rose only slightly. As a result, the Pcap,PAOP gradient decreased. Despite increased cardiac output, EVLW did not change by plasma expansion. Conclusion:, In this selected group of at-risk patients, the optimization of cardiac output guided by the concept of best individual filling pressure/stroke volume relationship did not worsen permeability pulmonary edema. [source] Structural and mechanical remodelling of the common bile duct after obstructionNEUROGASTROENTEROLOGY & MOTILITY, Issue 2 2002B. U. DUCH Biliary obstruction in man, most often caused by cholelithiasis, induces remodelling of the bile ducts. Obstruction-induced structural remodelling of the common bile duct (CBD) has been previously described. The mechanical changes that accompany the structural remodelling, however, have not been studied in detail. The aim of this study is to quantify the structural and mechanical changes in the CBD at different time intervals after acute obstruction. The CBD was ligated in the pig, near the duodenum, and studied after 3 h, 12 h, 2 days, 8 days and 32 days (n=5 in each group). One additional animal in each group was sham-operated. At each scheduled time, the CBD was mechanically tested in vitro with a computer-controlled volume infusion system to study the pressure,volume relationship of the CBD segment. A video camera provided simultaneous measurements of the outer dimensions of the CBD at the various pressures. The diameter and wall thickness of the CBD increased about three-fold in the 32-day group compared to the sham group (P < 0.001). The circumferential stress,strain relationship differed between groups (P < 0.001); it was shifted to the right, indicating softening, in the 3-h, 12-h, and 2-day groups and to the left, indicating stiffening, in the 8-day and 32-day group, compared to the sham group. The longitudinal stress,strain curves were all shifted to the left of the circumferential stress,strain curves (P < 0.05). The collagen area increased during obstruction (P < 0.001) but no correlation between the size of the collagen area and the biomechanical parameters was found. A practical implication of the present study serves as a warning to surgeons. A reduction in the wall stiffness in the first several days of obstruction along with an increased duct diameter and a decreased wall thickness suggest that operative procedures such as suturing, anastomosis and procedures related to ERCP must be performed with special care to avoid damage to the CBD. [source] Effects of combined inhibition of the Na+,H+ exchanger and angiotensin-converting enzyme in rats with congestive heart failure after myocardial infarctionBRITISH JOURNAL OF PHARMACOLOGY, Issue 5 2005Hartmut Ruetten We investigated the single vs the combined long-term inhibition of Na+,H+ exchanger-1 (NHE-1) and ACE in rats with congestive heart failure induced by myocardial infarction (MI). Rats with MI were randomized to receive either placebo, cariporide (3000 p.p.m. via chow), ramipril (1 mg kg,1 day,1via drinking water) or their combination for 18 weeks starting on day 3 after surgery. Cardiac morphology and function was assessed by echocardiography and by means of a 2.0 F conductance catheter to determine left ventricular (LV) pressure volume relationships. MI for 18 weeks resulted in an increase in LV end-diastolic diameter (LVDed) in the placebo-treated group when compared to sham (placebo: 1.1±0.04 cm; sham: 0.86±0.01; P<0.05). Combined inhibition of NHE-1 and ACE, but not the monotherapies, significantly reduced LVDed (1.02±0.02 cm). Preload recruitable stroke work (PRSW), dp/dtmax (parameter of systolic function) and end-diastolic pressure volume relationship (EDPVR, diastolic function) were significantly impaired in placebo-treated MI group (PRSW: 39±7 mmHg; dp/dtmax: 5185±363 mmHg s,1; EDPVR: 0.042±0.001 mmHg ,l,1; all P<0.05). Cariporide treatment significantly improved PRSW (64±7 mmHg), dp/dtmax (8077±525 mmHg s,1) and EDPVR (0.026±0.014 mmHg ,l,1), and reduced cardiac hypertrophy in rats with MI. Combined inhibition of NHE-1 and ACE had even a more pronounced effect on PRSW (72±5 mmHg) and EDPVR (0.026±0.014 mmHg ,l,1), as well as cardiac hypertrophy that, however, did not reach statistical significance compared to cariporide treatment alone. The NHE-1 inhibitor cariporide significantly improved LV remodeling and function in rats with congestive heart failure induced by MI. The effect of cariporide was comparable or tended to be stronger (e.g. systolic function) compared to ramipril. Combined treatment with cariporide and ramipril tended to be more effective on LV remodeling in rats with heart failure than the single treatments. Thus, inhibition of the NHE-1 may be a promising novel therapeutic approach for the treatment of congestive heart failure. British Journal of Pharmacology (2005) 146, 723,731. doi:10.1038/sj.bjp.0706381 [source] | ||||||||||