Effects of nitroglycerin on forearm haemodynamics in patients with cirrhosis

1. Basal forearm haemodynamics were studied by venous occlusion plethysmography in three groups of subjects: group I, healthy controls, group II, patients with cirrhosis age- and sex-matched with group I, and group III, an older group of patients with cirrhosis. Subsequently, responses to sublingual nitroglycerin were measured in group I and II subjects. 2. Controls responded to nitroglycerin with an increase in venous distensibility; group II patients had higher initial venous distensibility but did not respond to nitroglycerin. No other variables in either group were affected by nitroglycerin. 3. Group II and III patients differed in forearm blood flow and vascular resistance and venous distensibility. A significant inverse correlation was found between age and forearm blood flow (r = −0.57, P < 0.001) in all patients with cirrhosis. 4. We conclude that (a) venous tone is reduced in cirrhosis, possibly as a result of chronic venodilatation; (b) this venodilatation impedes further dilatory response to a small dose of nitroglycerin; (c) cirrhosis is also associated with age-related decreases in peripheral haemodynamics.

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Microvascular pressures measured by micropipettes in isolated edematous rabbit lungs

Journal of Applied Physiology ◽

10.1152/jappl.1986.60.2.539 ◽

1986 ◽

Vol 60 (2) ◽

pp. 539-545 ◽

Cited By ~ 22

Author(s):

J. U. Raj ◽

R. D. Bland ◽

S. J. Lai-Fook

Keyword(s):

Blood Flow ◽

Vascular Resistance ◽

Weight Ratio ◽

Dry Weight ◽

Pressure Profile ◽

Longitudinal Distribution ◽

Lung Edema ◽

Group Iii ◽

Group I ◽

Group Ii

To study the mechanical effects of lung edema on the pulmonary circulation, we determined the longitudinal distribution of vascular resistance in the arteries, veins, and microvessels, and the distribution of blood flow in isolated blood-perfused rabbit lungs with varying degrees of edema. Active vasomotor changes were eliminated by adding papaverine to the perfusate. In three groups of lungs with either minimal [group I, mean wet-to-dry weight ratio (W/D) = 5.3 +/- 0.6 (SD), n = 7], moderate (group II, W/D = 8.5 +/- 1.2, n = 10), or severe (group III, W/D = 9.9 +/- 1.6, n = 5) edema, we measured by direct micropuncture the pressure in subpleural arterioles and venules (20–60 micron diam) and in the interstitium surrounding these vessels. We also measured pulmonary arterial and left atrial pressures and lung blood flow, and in four additional experiments we used radio-labeled microspheres to determine the distribution of blood flow during mild and severe pulmonary edema. In lungs with little or no edema (group I) we found that 33% of total vascular pressure drop was in arteries, 60% was in microvessels, and 7% was in veins. Moderate edema (group II) had no effect on total vascular resistance or on the vascular pressure profile, but severe edema (group III) did increase vascular resistance without changing the longitudinal distribution of vascular resistance in the subpleural microcirculation. Perivascular interstitial pressure relative to pleural pressure increased from 1 cmH2O in group I to 2 in group II to 4 in group III lungs.(ABSTRACT TRUNCATED AT 250 WORDS)

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Ultrasound compared to Age Related Formulas for prediction of Pediatric Endotracheal Tube Size

QJM ◽

10.1093/qjmed/hcaa039 ◽

2020 ◽

Vol 113 (Supplement_1) ◽

Author(s):

A Abdelghany ◽

N Nasr ◽

S Talaat ◽

M Mansour ◽

T Shabana

Keyword(s):

Endotracheal Tube ◽

Airway Pressure ◽

Ultrasound Measurement ◽

Outer Diameter ◽

Transverse Diameter ◽

Tube Size ◽

Group Iii ◽

Age Related ◽

Group I ◽

Group Ii

Abstract Background In pediatric patients, having proper size of endotracheal tube (ETT) is crucial. The practice of using age-based formulas to calculate the ETT size is easy, practical and commonly used today. However, the incidence of inappropriate tube size is still judicious, hence increasing risk from changing tube such as trauma and aspiration. Recent studies found that measuring the narrowest transverse subglottic diameter may guide the proper tube size Aim This study was aimed to proof that selecting ETT size using ultrasound measurement of subglottic diameter is a reliable method and lead to less frequency of changing tube size than age-based formula especially in older children Materials and Methods 60 children aged between 2 to 12 years, of both genders, American society of anesthesiologists (ASA) I or II physical status scheduled for day case surgery under general endotracheal anesthesia. Children were divided randomly according to age into three groups: group I included children aged between 2 to < 5 years, group II included children aged between 5 to < 9 years, and group III included children aged between 9 to 12 years. In all childern, the size of the ETT was determined according to both ultrasonography and modified cole's formula. The size of the ETT initially inserted was based on ultrasonographic calculation. Ultrasonography is done using high–resolution linear ultrasound probe. The probe was positioned at the anterior aspect of neck in the midline with the head extended and neck flexed (sniffing position). The minimal transverse diameter of the subglottic airway (MTDSA) was estimated at the level of cricoid cartilage at zero cmH2O airway pressure. After measurement of the subglottic diameter, uncuffed ETT with the nearest outer diameter (OD) corresponding to the measured subglottic diameter was selected for intubation. If there was resistance to ETT passage into the trachea, or there was no audible leak when the lungs were inflated to a pressure of 20–30 cm H2O, the tube was exchanged with one that is 0.5 mm smaller. In contrast, the ETT was exchanged for one that is 0.5 mm larger if leaks occurred at an inflation pressure less than 10 cm H2O. Optimal tube size was clinically determined by leakage at airway pressure of 10-20 cmH2O. Results Linear correlation study showed that Ultrasonography was a better predictor for optimal ETT size in pediatrics than Cole's formula for all studied groups especially in older age groups (although both were significant); being 0.669 Vs. 0.613 among group I; 0.955 Vs. 0.808 among group II and 0.863 Vs. 0.707 among group III. Multi-regression analysis showed that both Ultrasonography & Cole's formula were highly sensitive independent predictors that can predict Optimal ETT size in pediatrics (F-Ratio = 524.7, p < 0.001); The prediction formula is: Optimal ETT size ID = -0.091 + 0.814(ID obtained by US) + 0.192(ID obtained by Cole's formula). Conclusion Ultrasound is a safe, reliable, non-invasive tool for selection of appropriately sized endotracheal tube for clinical use. Our study validates the reliability of ultrasound to measure subglottic diameter which avoids intubation related complications of either trauma or inefficient ventilation.

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Different Bleeding Patterns with the Use of Levonorgestrel Intrauterine System: Are They Associated with Changes in Uterine Artery Blood Flow?

BioMed Research International ◽

10.1155/2014/815127 ◽

2014 ◽

Vol 2014 ◽

pp. 1-6 ◽

Cited By ~ 5

Author(s):

Carlo Bastianelli ◽

Manuela Farris ◽

Stefania Rapiti ◽

Roberta Bruno Vecchio ◽

Giuseppe Benagiano

Keyword(s):

Blood Flow ◽

Uterine Artery ◽

Endometrial Thickness ◽

Power Doppler ◽

Artery Blood Flow ◽

Group Iii ◽

Group I ◽

Significant Difference ◽

Before And After ◽

Group Ii

Objective. Evaluate if different bleeding patterns associated with the use of the levonorgestrel intrauterine system (LNG-IUS) are associated with different uterine and endometrial vascularization patterns, as evidenced by ultrasound power Doppler analysis.Methodology. A longitudinal study, with each subject acting as its own control was conducted between January 2010 and December 2012. Healthy volunteers with a history of heavy but cyclic and regular menstrual cycles were enrolled in the study. Ultrasonographic examination was performed before and after six months of LNG-IUS placement: uterine volume, endometrial thickness, and subendometrial and myometrial Doppler blood flow patterns have been evaluated.Results. A total of 32 women were enrolled out of 186 initially screened. At six months of follow-up, all subjects showed a reduction in menstrual blood loss; for analysis, they were retrospectively divided into 3 groups: normal cycling women (Group I), amenorrheic women (Group II), and women with prolonged bleedings (Group III). Intergroup analysis documented a statistically significant difference in endometrial thickness among the three groups; in addition, mean pulsatility index (PI) and resistance index (RI) in the spiral arteries were significantly lower in Group I and Group III compared to Group II. This difference persisted also when comparing—within subjects of Group III—mean PI and RI mean values before and after insertion.Conclusions. The LNG-IUS not only altered endometrial thickness, but—in women with prolonged bleedings—also significantly changed uterine artery blood flow. Further studies are needed to confirm these results and enable gynecologists to properly counsel women, improving initial continuation rates.

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Effect of norepinephrine on diaphragm contractility and blood flow

Journal of Applied Physiology ◽

10.1152/jappl.1990.69.6.2019 ◽

1990 ◽

Vol 69 (6) ◽

pp. 2019-2028 ◽

Cited By ~ 10

Author(s):

G. S. Supinski ◽

A. F. DiMarco ◽

J. Gonzalez ◽

M. D. Altose

Keyword(s):

Blood Flow ◽

Group Iv ◽

Arterial Flow ◽

Force Frequency ◽

Group Iii ◽

Arterial Blood ◽

Group I ◽

Intramuscular Electrodes ◽

Phrenic Artery ◽

Group Ii

Recent studies have shown that diaphragm fatigue can be reversed by mechanical augmentation of phrenic arterial flow. The purpose of the present experiment was to determine whether it was possible to pharmacologically augment diaphragm blood flow and reverse fatigue by the administration of norepinephrine. Four groups of studies were performed, all employing our previously described in situ isometric canine diaphragm strip preparation (Supinski et al., J. Appl. Physiol. 60: 1789-1796, 1986). Group I studies examined the effects of norepinephrine on the contractility of the nonfatigued diaphragm in normotensive dogs, group II studies examined the effects of this drug on the contractility of the fatigued diaphragm in normotensive animals, and group III studies examined the effect of this drug on the contractility of the fatigued diaphragm in hypotensive animals. Group IV studies examined the effect of norepinephrine in normotensive animals in which the phrenic artery was cannulated and pump perfused at constant flow. Fatigue was induced in group II, III, and IV studies by rhythmically stimulating the diaphragm via intramuscular electrodes. Norepinephrine had no effect on the contractility of the nonfatigued diaphragm (group I). In normotensive (group II) and hypotensive animals (group III), norepinephrine elicited dramatic increases in arterial blood pressure and phrenic arterial flow and produced a significant upshift in the force-frequency curve of the fatigued diaphragm. However, when phrenic flow was held constant (group IV experiments), norepinephrine failed to augment the contractility of the fatigued diaphragm. These results indicate that 1) norepinephrine can increase phrenic blood flow and augment the contractility of the fatigued diaphragm in both normotensive and hypotensive conditions and 2) this effect of norepinephrine to partially reverse fatigue is secondary to its action to augment diaphragmatic blood flow.

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Comparative Study on the Effect of Adipose tissue derived Mesenchymal Stem Cells versus Metformin on Age-related Structural Changes of the Cerebellum in Albino Rat

QJM ◽

10.1093/qjmed/hcab099.003 ◽

2021 ◽

Vol 114 (Supplement_1) ◽

Author(s):

M. M Doaa Karem ◽

Soheir K Ahmed ◽

Hanan A Saleh ◽

Ghada Galal Hamam

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Adipose Tissue ◽

Purkinje Cells ◽

Structural Changes ◽

Female Rats ◽

Group Iii ◽

Age Related ◽

Group I ◽

Group Ii

Abstract Introduction Aging is a normal physiological process that affects all organs in the body including the cerebellum. Metformin is an anti-diabetic drug that is used in some age-related diseases. Regenerative medicine using adipose tissue derived mesenchymal stem cells (ADMSCs) is an emerging promising strategy. Aim to compare between the role of ADMSCs and metformin on the age-related structural changes of the cerebellum in female albino rats. Materials and methods Fifty-five female rats of different ages (4, 12 and 24 months) were included in this study. They were divided into three groups according to their ages: Group I (Adult rats), Group II (Old rats) and Group III (Senile rats). Group II and Group III were subdivided into three subgroups, Subgroup a: rats were left without treatment, Subgroup b: rats were given a single dose of 1X106 ADMSCs via tail vein. Subgroup c: Rats received300 mg/kg metformin/day orally. Rats were sacrificed after four weeks. The cerebellum was collected and processed for H&E, Toluidine blue and immuno-histochemical reaction using glial fibrillary acidic protein (GFAP). Results Histological examination of the cerebellum of the subgroups IIa and IIIa revealed age-related structural changes in comparison to group I. Purkinje cells appeared distorted with irregular outline. Some Purkinje cells were seen shrunken while others appeared ballooned. Focal loss of Purkinje cells was also noticed. Granular layer contained small widely separated granule cells. GFAP reaction revealed an apparent decrease in number of astrocytes and their processes. The structural changes were more obvious in subgroup IIIa. In ADMSCs treated subgroups (IIbandIIIb); more noticeable improvement of these changes was noticed compared to the corresponding metformin treated subgroups (IIc and IIIc). Conclusion ADMSCs was more effective than metformin in preventing some age-related structural changes of the cerebellum.

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Ageing is associated with impairment of nitric oxide and prostanoid dilator pathways in the human forearm

Clinical Science ◽

10.1042/cs1020595 ◽

2002 ◽

Vol 102 (5) ◽

pp. 595-600 ◽

Cited By ~ 50

Author(s):

Nivedita SINGH ◽

Sanjay PRASAD ◽

Donald R.J. SINGER ◽

Raymond J. Mac ALLISTER

Keyword(s):

Nitric Oxide ◽

Blood Flow ◽

Forearm Blood Flow ◽

Area Under The Curve ◽

Venous Occlusion ◽

Response Curves ◽

Age Related ◽

Older Subjects ◽

Synthase Inhibitor ◽

Dose Dependent

Ageing is associated with endothelial dysfunction and increased cardiovascular risk. We assessed the activity of nitric oxide (NO) and prostaglandin pathways in older subjects. Bilateral venous occlusion plethysmography was used to measure forearm blood flow during intra-arterial infusion of the NO synthase inhibitor, NG-monomethyl-l-arginine (l-NMMA; 1, 2 and 4μmol/min), the cyclo-oxygenase inhibitor, aspirin (3, 9 and 30μmol/min), and the smooth muscle constrictor, noradrenaline (60, 120 and 240pmol/min); each dose infused for 5min. Eighteen young and 15 healthy older subjects (mean age±S.E.M., 32±1 and 65±1 years respectively) were studied. Effects of treatment were calculated from the ratio of blood flow in the infused to control arm, expressed as a percentage. Dose-response curves were compared by analysis of the area under the curve (AUC) using independent samples t test. All agents caused dose-dependent decreases in basal forearm blood flow. AUC values for noradrenaline, aspirin and l-NMMA in younger and older subjects were 162±24, 173±24 and 170±17, and 138±22, 70±22 and 89±22 respectively. Effects of aspirin and l-NMMA, but not noradrenaline, were reduced in older subjects (P = 0.004, 0.007 and 0.461 respectively). Our findings suggest a generalized abnormality of basal endothelial function in older people, with similar impairment of NO and prostanoid dilator pathways. Defects in both pathways could contribute to the development of age-related cardiovascular disease.

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Venous Constriction in Response to Head-Up Tilt in Man

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y72-047 ◽

1972 ◽

Vol 50 (4) ◽

pp. 317-320 ◽

Cited By ~ 2

Author(s):

Lars O. Boréus ◽

Norman K. Hollenberg

Keyword(s):

Blood Flow ◽

Forearm Blood Flow ◽

Marked Decrease ◽

Technical Difficulty ◽

Venous Occlusion ◽

Venous System ◽

Postural Stress ◽

Venous Distensibility ◽

Head Up Tilt

There has been disagreement about the role of the peripheral venous system in cardiovascular adjustments to postural stress in man. In part this seems to be due to the technical difficulty in determining venous distensibility by plethysmographic techniques in situations where concomitant changes in blood flow occur. We have demonstrated in this study that rapid and consistent increases in forearm venous tone assessed by venous occlusion plethysmography do occur on head-up tilt in man, and that they can be readily masked by the parallel marked decrease in forearm blood flow. It is concluded that the peripheral venous system in man is not designed to function only in states of severe stress but rather plays an important role in moment-to-moment adjustments of cardiovascular activity.

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Treatment and Prevention of Diaphragm Fatigue Using Low-Dose Dopamine

Biological Research For Nursing ◽

10.1177/1099800402003003004 ◽

2002 ◽

Vol 3 (3) ◽

pp. 140-149 ◽

Cited By ~ 9

Author(s):

Janet D. Pierce ◽

Richard L. Clancy ◽

Nan Smith-Blair ◽

Robert Kraft

Keyword(s):

Blood Flow ◽

Intensive Care ◽

Intensive Care Units ◽

Low Dose ◽

Aortic Blood Flow ◽

Group Iii ◽

Aortic Blood ◽

Group I ◽

Group Ii ◽

Diaphragm Fatigue

There is increasing evidence that diaphragm fatigue is a major cause of failure in weaning patients frommechanical ventilation. Patients in intensive care units are often administered dopamine to improve renal blood flow without regard to its effect on diaphragmblood flow. The aimof this study was to investigate if intravenous low-dose dopamine, equivalent to the dose used in intensive care units, can treat and prevent diaphragmfatigue. Diaphragmfatigue was produced in anesthetized rats by inspiratory resistance loading (IRL). The effect on diaphragmshortening, diaphragmblood flow, and aortic blood flow was determined. When diaphragm fatigue was attained, group I was given saline for 30 min while maintaining IRL. At the time of diaphragm fatigue, group II was given low-dose dopamine (2 μg/kg/min) for 30 min while maintaining IRL. In group III, dopamine administration was started before and continued throughout the period of IRL. Administering dopamine after the development of diaphragm fatigue (group II) increased diaphragm performance as measured by increased diaphragmshortening and was accompanied by an increased diaphragmblood flow. Administering dopamine prior to and throughout IRL (group III) prevented diaphragmfatigue. Low-dose dopamine can prevent and/or reverse diaphragmfatigue in rats without a significant change in aortic blood flow. This effect of dopamine may be due to increased oxygen delivery associated with the increased diaphragm blood flow, resulting in less free radical formation and thus less muscle damage.

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Enhanced Platelet Thromboxane Synthesis In Normotensive And Hypertensive Pregnancies With Insufficient Fetal Growth

10.1055/s-0038-1653378 ◽

1981 ◽

Author(s):

H C S Wallenburg ◽

P Rotmans

Keyword(s):

Blood Flow ◽

Platelet Aggregation ◽

Fetal Growth ◽

Gestational Age ◽

Control Group ◽

Group Iii ◽

Group I ◽

Group Ii ◽

Generating System ◽

Platelet Thromboxane

In normal pregnancy platelet aggregation and blood flow in the uterine arteries could be modulated by the balance between the prostacyclin-generating system in the uterine arterial walls and the thromboxane-generating system in platelets. Since hypertensive pregnancies and pregnancies complicated by insufficient fetal growth are characterized by a diminished uteroplacental blood flow,the present study was performed to investigate platelet thromboxane synthesis in these conditions.Material and methods. The study was performed in a control group of 27 women with uncomplicated pregnancies and adequate-for-gestational age (AGA)infants(group I),23 women with uncomplicated pregnancies but small-for-gestational age(SGA) infants(group II); 18 women with pregnancy-induced hypertension (PIH) and AGA-infants(group III); 16 women with PIH and SGA infants(group V).All women were investigated in the last trimester of pregnancy. Venous blood was obtained in EDTA. Platelet aggregation was induced with thrombin( l I.U./ml final concentration)in platelet-rich plasma, and the amount of malondehyde(MDA)generated was measured spectrophotometrically after reaction with thiobarbituric acid. The amount of MDA is equivalent to that of HHT and a measure of the formation of thromboxane.Results. The amount of MDA (mmol/109 platelets ± S.D.)formed in group I was 5.35±0.8, in group II 6.32± 1.4,in group III 6.3 ± 1.5, and in group IV 6.4 ± 1.8. Groups II, III and IV were not different from each other, but were all significantly higher than group I(p < 0.01).Conclusion. The results indicate that pregnant women with a high incidence of a compromised uterine circulation-normotensive with SGA, hypertensive with AGA or SGA- as a group exhibit a more active platelet thromboxane-synthesis. This might be due to defective production of PGI2 by the uterine arterial wall.

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The Impact of Blood Flow Rate and Duration of Dialysis Session on Nutritional Status in Hemodialysis Patients

Global Journal of Health Science ◽

10.5539/gjhs.v12n11p106 ◽

2020 ◽

Vol 12 (11) ◽

pp. 106

Author(s):

Nur Samsu ◽

Fatmawati Fatmawati ◽

Aurora Permatasari ◽

Kartin Kartin ◽

Wahyu Wulandari

Keyword(s):

Blood Flow ◽

Nutritional Status ◽

Flow Rate ◽

Blood Flow Rate ◽

Group Iii ◽

Class A ◽

Group I ◽

Group Ii ◽

The Impact ◽

Dialysis Time

BACKGROUND: Blood flow rate (BFR) and time of dialysis are important determinants of dialysis adequacy. This study aimed to determine the impact of higher BFR and longer dialysis time on nutritional status in chronic hemodialysis (HD) patients. METHODS: Real-world evidence (RWE) studies of 3 HD units in different hospitals that differ in BFR and/or dialysis time. Group I, HD 5 hr and BFR 200-250 mL/min; group II, HD 4 hr and BFR 270-320 mL/min, and group III, HD 4 hr and BFR 200-250 mL/min. All HD units use the same dialysate flow and dialysis frequency. Nutritional status was assessed using a 3-point scale Subjective Global Assessment. RESULTS: A total of 233 chronic HD patients were included, mean of age was 52 ± 12.9 years, 46.5% were male. There are 69.5% on SGA class A, 27.5% on SGA class B, and 3% on SGA class C. The proportion of SGA class A in group II was highest compared to group II and III (93.5% vs 79.0% vs 32.1% (p <0.05). There was no SGA class C in group II, whereas 2.4% in group I and 7.4% in group III. In group II there was lower interdialytic weight gain (IDWG) and less use of anti-hypertensive drugs compared to group III (p <0.05). CONCLUSION: Our study showed that higher BFR and longer dialysis time are associated with better nutritional status in chronic HD patients. A higher BFR seems to have a more substantial impact compared to a longer dialysis time. Keywords: blood flow rate, dialysis time, subjective global assessment, nutritional status

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