Aortic regurgitation pathophysiology
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This document discusses the pathophysiology of aortic regurgitation. In chronic aortic regurgitation, the left ventricle undergoes compensatory mechanisms to maintain cardiac output, including increasing end diastolic volume, chamber compliance, and total stroke volume. This results in eccentric left ventricular hypertrophy. Over time, increased afterload leads to concentric hypertrophy as well. In some patients, the compensatory mechanisms eventually fail, resulting in left ventricular systolic dysfunction and heart failure symptoms. Early afterload reduction therapy can potentially reverse the compensatory changes and reduce regurgitation severity.
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1. Pulmonary ventilation is the volume of air entering the lungs each minute, typically 500mL tidal volume at 12 breaths per minute for 6L/min total.
2. Alveolar ventilation is the volume of new air entering the alveoli each minute, calculated as tidal volume minus dead space.
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“The ratio of alveolar ventilation and the amount of blood that perfuse the alveoli”.
FORMULA
It is expressed as VA/Q.
VA is alveolar ventilation
Q is the blood flow (perfusion)
Normal value of ventilation perfusion ratio is about
0.8
VA is 4.2 L /min
Q is 5.5 L/min (Same as Cardiac output)
So VA/Q = 4.2/5.5 = 0.8
If VA becomes zero ratio becomes zero
If Q becomes zero ratio becomes infinite.
If ratio becomes zero or infinite then there is no gaseous exchange. So this ratio indicates the efficiency of gaseous exchange in lungs.
In standing or sitting position this ratio is not uniform in all parts of the lungs.
In standing position, in upper parts of lungs there is almost no blood flow so normally in upper parts of lungs the ratio is higher may be near 3.
In lower part of lungs, there is more blood flow so the ratio is decreased may be 0.6.
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When there is higher VA/Q ratio, PO2 and PCO2 in the alveolar air resembles the values in the inspired air.
When exchange is not occurring because of lack of perfusion, inspired air goes to alveoli, as there is no exchange occurring so the same values of PCO2 and PO2 as in inspired air.
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website: http://www.am-medicine.com
Facebook page : https://www.facebook.com/pages/Am-medicine/207726329406832
Facebook group: https://www.facebook.com/groups/1409138472653811/
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Ventilation and perfusion in the lungs are not evenly distributed. Ventilation is greater in the lung bases which are on the steeper part of the compliance curve, while perfusion is greatest in the bases due to the effects of gravity and the pulmonary arterial pressure gradient. The optimal ventilation to perfusion (V/Q) ratio is 1 to allow for efficient gas exchange, but V/Q ratios vary throughout the lungs from greater than 1 in the apices to less than 1 in the bases. Extreme V/Q mismatching occurs when areas have no ventilation (shunt) or no perfusion (dead space), worsening oxygen and carbon dioxide exchange.
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1. Pulmonary ventilation is the volume of air entering the lungs each minute, typically 500mL tidal volume at 12 breaths per minute for 6L/min total.
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Ventilation perfusion ratio is :
“The ratio of alveolar ventilation and the amount of blood that perfuse the alveoli”.
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It is expressed as VA/Q.
VA is alveolar ventilation
Q is the blood flow (perfusion)
Normal value of ventilation perfusion ratio is about
0.8
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Q is 5.5 L/min (Same as Cardiac output)
So VA/Q = 4.2/5.5 = 0.8
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If Q becomes zero ratio becomes infinite.
If ratio becomes zero or infinite then there is no gaseous exchange. So this ratio indicates the efficiency of gaseous exchange in lungs.
In standing or sitting position this ratio is not uniform in all parts of the lungs.
In standing position, in upper parts of lungs there is almost no blood flow so normally in upper parts of lungs the ratio is higher may be near 3.
In lower part of lungs, there is more blood flow so the ratio is decreased may be 0.6.
In certain diseases the VA/Q ratio is higher which means perfusion is inadequate i.e. in some parts of lungs the alveoli are non functional or partially functional. This is seen in cases of pulmonary thrombosis or embolism.
When there is higher VA/Q ratio, PO2 and PCO2 in the alveolar air resembles the values in the inspired air.
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website: http://www.am-medicine.com
Facebook page : https://www.facebook.com/pages/Am-medicine/207726329406832
Facebook group: https://www.facebook.com/groups/1409138472653811/
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3. The muscles of respiration including the diaphragm and intercostal muscles which contract to inhale and exhale air.
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The increase in pulmonary vascular resistance (PVR) in ARDS can be secondary either to « structural » mechanisms related to lung injury per se and to « functional » mechanisms related to the effects of mechanical ventilation with positive end expiratory pressure (PEEP). The latter mechanism is enhanced when PEEP overdistends more than it recruits lung volume and when tidal volume (VT) is high. The recommended protective ventilation with low VT and PEEP adjusted to driving pressure can also reduce the RV afterload. A reduced central blood volume can also play a role in the increase in PVR (extension of the West’s zone 2). In this case, volume administration can reduce the PVR and improve the RV function. Finally, prone positioning also exerts a beneficial effect on RV afterload through a decrease in PVR (lung recruitment, decrease in hypoxic vasoconstriction, increase in central blood volume with decrease in the extent of zone 2).
In acute PE, RV dysfunction is associated with poor outcome. Thrombolytic treatment, which is indicated in cases of severe PE with shock, prevents hemodynamic decompensation in patients with intermediate risk PE, but also results in increased risk of severe hemorrhage and stroke. In the case of PE with low cardiac output and no RV dilatation, fluid administration can be indicated to improve cardiac output. In cases of systemic arterial hypotension, vasopressors such as norepinephrine can be indicated to restore adequate RV perfusion pressure. Indication of inotropic agents such as dobutamine, which improves the RV-pressure artery coupling should be evaluated individually. Surgical pulmonary embolectomy can be indicated when the thrombolytic therapy is contra-indicated in acute PE with shock. Constrictive pericarditis
- Constrictive pericarditis results from scarring and loss of elasticity of the pericardial sac, typically due to chronic inflammation and sometimes calcification. This causes the pericardium to thicken and lose its ability to expand and contract normally.
- The inelastic pericardium prevents normal filling of the heart chambers, especially in mid to late diastole. Inspiration does not decrease pressure in the left ventricle as it normally would due to the thickened pericardium isolating the heart.
- Diagnosis involves physical exam findings like elevated JVP, hepatomegaly, and Kussmaul's sign combined with echocardiography findings like sept
Hemodynamics - paradigm shifts
Paradigms have been shifting.
Flow-centered ideas, ventriculo-arterial coupling and redistributions between compartments with different time constants.
Control of-respiration
website: http://www.am-medicine.com
Facebook page : https://www.facebook.com/pages/Am-medicine/207726329406832
Facebook group: https://www.facebook.com/groups/1409138472653811/
Duplex assessment of venous hemodynamics 3 oct 13th, 2011, morning 20mn2
This document discusses duplex assessment of venous hemodynamics. It describes how duplex ultrasound can be used to assess venous hemodynamic changes through maneuvers like Valsalva and Parana. This allows for evaluation of valve competence and incompetence, as well as identifying different hemodynamic configurations like closed and open shunts. Understanding venous hemodynamics through duplex assessment is important for accurate diagnosis and treatment of venous disease.
Essential Hypertension
Hypertension, or high blood pressure, affects over 1 billion people worldwide and is a major risk factor for heart attacks and strokes. It is defined as a systolic blood pressure over 140 mmHg or a diastolic blood pressure over 90 mmHg. Essential or primary hypertension accounts for 90-95% of hypertension cases and results from an interaction of environmental and genetic factors, though the specific causes are unknown. If left untreated, hypertension can damage organs like the heart, brain, and kidneys, potentially leading to heart attacks, strokes, kidney failure or other complications. Treatment involves lifestyle modifications and medication to control blood pressure and reduce health risks.
Cardiopulmonary exercise testing.pptx
Cardiopulmonary exercise testing (CPET) provides an integrated evaluation of the cardiorespiratory system during exercise. It has several indications including undiagnosed exercise intolerance, assessment of exercise tolerance in known cardiac or pulmonary diseases, and preoperative evaluation. CPET evaluates various cardiovascular and respiratory responses to exercise including oxygen uptake, ventilatory threshold, and heart rate. It has clinical applications in assessing heart failure, dyspnea, and other cardiac and pulmonary conditions.
Failing Right Ventricle in PAH , How to manage?
The document discusses the management of a failing right ventricle in pulmonary arterial hypertension (PAH). It begins by describing the natural history of idiopathic PAH and the predictors of survival. It then discusses the physiology of the right ventricle, how it is linked to the left ventricle, and the determinants of right ventricular function. The document concludes by outlining the goals and general management strategies for chronic and acute right ventricular failure in PAH.
ascites
This document discusses ascites, which is free fluid in the abdominal cavity. It describes the pathophysiology of ascites, which can be due to increased hydrostatic pressure (e.g. in cirrhosis), increased osmotic pressure, or impaired fluid resorption. The diagnosis involves history of increased abdominal size and physical exam findings like shifting dullness. Imaging studies like ultrasound can detect small amounts of fluid. Treatment involves dietary sodium restriction, diuretics, and paracentesis for symptomatic relief. Surgical options include shunt procedures for refractory ascites.
Fluid responsiveness in critically ill patients
This document discusses fluid responsiveness in critically ill patients. It begins by defining fluid responsiveness as an increase in cardiac index after fluid infusion. It then describes three scenarios involving fluid resuscitation: patients with acute blood or fluid loss requiring immediate resuscitation, patients with suspected septic shock where early goal-directed therapy with fluids is important, and ICU patients who have already received fluids and their fluid responsiveness needs to be assessed. The document discusses various methods of assessing preload and preload dependence, including filling pressures, volumes, respiratory variations in inferior vena cava diameter, inspiratory drops in right atrial pressure, and predicting responsiveness through respiratory variations in parameters related to cardiac index. It emphasizes that preload alone
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Management of acute right heart failure by Professor Jean- Louis Teboul
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Unlocking the mysteries of reproduction: Exploring fecundity and gonadosomati...
The pygmy halfbeak Dermogenys colletei, is known for its viviparous nature, this presents an intriguing case of relatively low fecundity, raising questions about potential compensatory reproductive strategies employed by this species. Our study delves into the examination of fecundity and the Gonadosomatic Index (GSI) in the Pygmy Halfbeak, D. colletei (Meisner, 2001), an intriguing viviparous fish indigenous to Sarawak, Borneo. We hypothesize that the Pygmy halfbeak, D. colletei, may exhibit unique reproductive adaptations to offset its low fecundity, thus enhancing its survival and fitness. To address this, we conducted a comprehensive study utilizing 28 mature female specimens of D. colletei, carefully measuring fecundity and GSI to shed light on the reproductive adaptations of this species. Our findings reveal that D. colletei indeed exhibits low fecundity, with a mean of 16.76 ± 2.01, and a mean GSI of 12.83 ± 1.27, providing crucial insights into the reproductive mechanisms at play in this species. These results underscore the existence of unique reproductive strategies in D. colletei, enabling its adaptation and persistence in Borneo's diverse aquatic ecosystems, and call for further ecological research to elucidate these mechanisms. This study lends to a better understanding of viviparous fish in Borneo and contributes to the broader field of aquatic ecology, enhancing our knowledge of species adaptations to unique ecological challenges.
BREEDING METHODS FOR DISEASE RESISTANCE.pptx
Plant breeding for disease resistance is a strategy to reduce crop losses caused by disease. Plants have an innate immune system that allows them to recognize pathogens and provide resistance. However, breeding for long-lasting resistance often involves combining multiple resistance genes
Bob Reedy - Nitrate in Texas Groundwater.pdf
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Nucleophilic addition is the most important reaction of carbonyls. Not just aldehydes and ketones, but also carboxylic acid derivatives in general.
Carbonyls undergo addition reactions with a large range of nucleophiles.
Comparing the relative basicity of the nucleophile and the product is extremely helpful in determining how reversible the addition reaction is. Reactions with Grignards and hydrides are irreversible. Reactions with weak bases like halides and carboxylates generally don’t happen.
Electronic effects (inductive effects, electron donation) have a large impact on reactivity.
Large groups adjacent to the carbonyl will slow the rate of reaction.
Neutral nucleophiles can also add to carbonyls, although their additions are generally slower and more reversible. Acid catalysis is sometimes employed to increase the rate of addition.
如何办理(uvic毕业证书)维多利亚大学毕业证本科学位证书原版一模一样
原版纸张【微信：741003700 】【(uvic毕业证书)维多利亚大学毕业证】【微信：741003700 】学位证，留信认证（真实可查，永久存档）offer、雅思、外壳等材料/诚信可靠,可直接看成品样本，帮您解决无法毕业带来的各种难题！外壳，原版制作，诚信可靠，可直接看成品样本。行业标杆！精益求精，诚心合作，真诚制作！多年品质 ,按需精细制作，24小时接单,全套进口原装设备。十五年致力于帮助留学生解决难题，包您满意。
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留信网认证的作用:
1:该专业认证可证明留学生真实身份
2:同时对留学生所学专业登记给予评定
3:国家专业人才认证中心颁发入库证书
4:这个认证书并且可以归档倒地方
5:凡事获得留信网入网的信息将会逐步更新到个人身份内，将在公安局网内查询个人身份证信息后，同步读取人才网入库信息
6:个人职称评审加20分
7:个人信誉贷款加10分
8:在国家人才网主办的国家网络招聘大会中纳入资料，供国家高端企业选择人才
bordetella pertussis.................................ppt
Bordettela is a gram negative cocobacilli spread by air born drop let
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...
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Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/Thornton ESPP slides UK WW Network 4_6_24.pdf
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When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
Perhaps most importantly, Thermodynamics rapidly became a primary tool in the advance of applied science/engineering/technology, spanning micro-tech, to aerospace and cosmology. I can think of no better a story to illustrate the breadth of scientific methodologies and applications at their best.
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(Work in progress.)
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Micronuclei test.M.sc.zoology.fisheries.
Current Ms word generated power point presentation covers major details about the micronuclei test. It's significance and assays to conduct it. It is used to detect the micronuclei formation inside the cells of nearly every multicellular organism. It's formation takes place during chromosomal sepration at metaphase.
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
The use of Nauplii and metanauplii artemia in aquaculture (brine shrimp).pptx
Although Artemia has been known to man for centuries, its use as a food for the culture of larval organisms apparently began only in the 1930s, when several investigators found that it made an excellent food for newly hatched fish larvae (Litvinenko et al., 2023). As aquaculture developed in the 1960s and ‘70s, the use of Artemia also became more widespread, due both to its convenience and to its nutritional value for larval organisms (Arenas-Pardo et al., 2024). The fact that Artemia dormant cysts can be stored for long periods in cans, and then used as an off-the-shelf food requiring only 24 h of incubation makes them the most convenient, least labor-intensive, live food available for aquaculture (Sorgeloos & Roubach, 2021). The nutritional value of Artemia, especially for marine organisms, is not constant, but varies both geographically and temporally. During the last decade, however, both the causes of Artemia nutritional variability and methods to improve poorquality Artemia have been identified (Loufi et al., 2024).
Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry (Mozanzadeh et al., 2021). Culture and harvesting of brine shrimp eggs represents another aspect of the aquaculture industry. Nauplii and metanauplii of Artemia, commonly known as brine shrimp, play a crucial role in aquaculture due to their nutritional value and suitability as live feed for many aquatic species, particularly in larval stages (Sorgeloos & Roubach, 2021).
Sharlene Leurig - Enabling Onsite Water Use with Net Zero Water
Sharlene Leurig - Enabling Onsite Water Use with Net Zero WaterTexas Alliance of Groundwater Districts
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bordetella pertussis.................................ppt
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3D Hybrid PIC simulation of the plasma expansion (ISSS-14)
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Applied Science: Thermodynamics, Laws & Methodology.pdf
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8.Isolation of pure cultures and preservation of cultures.pdf
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EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
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The use of Nauplii and metanauplii artemia in aquaculture (brine shrimp).pptx
Sharlene Leurig - Enabling Onsite Water Use with Net Zero Water
Sharlene Leurig - Enabling Onsite Water Use with Net Zero Water
Aortic regurgitation pathophysiology
- 1. AORTIC REGURGITATION - PATHOPHYSIOLOGY Dr Kunwar Sidharth Saurabh
- 3. ETIOLOGY
- 6. PATHOPHYSIOLOGY • VOLUME LOAD – COMPENSATORY MECHANISMS – LV END DIASTOLIC VOLUME INCREASES TO ACCOMMODATE REGURGITANT VOLUME – ALONG WITH INCREASE IN CHAMBER COMPLIANCE – HENCE, THERE IS NO INCREASE IN DIASTOLIC FILLING PRESSURE
- 7. Cont.. – INCREASE IN EDV INCREASE TOTAL STROKE VOLUME – HENCE, FORWARD STROKE VOLUME MAINTAINED WITHIN NORMAL RANGE – ALSO, ADAPTATION TO VOLUME OVERLOAD IS BY NEW SARCOMERES CAUSING “ECCENTRIC LV HYPERTROPHY”
- 8. Cont.. LV PRELOAD INCREASES PRELOAD AT SACRCOMERE LEVEL IS NEAR NORMAL CONTRACTILE FUNCTION PRESERVED ENHANCED TOTAL STROKE VOLUME
- 9. Cont.. LV PRELOAD RESERVE MAINTAINED LV EJECTION PERFORMANCE MAINTAINED FRACTIONAL SHORTENING REMAINS IN NORMAL RANGE
- 10. Cont.. AUGMENTED CHAMBER VOLUME INC SYSTOLIC WALL STRESS AND AFTERLOAD AFTERLOAD INCREASE IN STIMULUS FOR CONCENTRIC HYPERTROPHY
- 11. Cont.. • THUS “AR – CHRONIC” IS A CONDITION OF COMBINED – VOLUME OVERLOAD – PRESSURE OVERLOAD • HENCE THERE IS BOTH – – ECCENTRIC HYPERTROPHY – CONCENTRIC HYPERTROPHY
- 12. POINTS TO NOTE - • DUE TO COMPENSATORY PROCESSES- – PATIENT MAY REMAIN ASYMPTOMATIC FOR DECADES – AFTER LOAD REDUCTION THERAPY HAS POTENTIAL TO REDUCE DEGREE OF REGURGITATION VIA – • REDUCES AFTERLOAD AND COMPENSATORY DILATATION AND HYPERTROPHY
- 13. Cont.. • In some patients compensatory process cannot be maintained for long • Results in LV systolic dysfunction • Symptoms of dyspnoea and fatigue often develops at this transition point. • Process is mostly insiduos
- 14. IMPORTANT TO NOTE LV SYSTOLIC DYSFUNCTION AFTERLOAD MISMATCH REVERSIBLE AVR CAUSES COMPLETE REVERSAL IMPAIRED MYOCARDIAL CONTRACTILITY IRREVERSIBLE