Pulmonary Hypertension Pathophysiology

As this disease progresses and the workload of the heart is consistently increased, ventricular hypertrophy occurs. At first, the hypertrophied heart muscles will increase contractility, thus increasing cardiac output; however, as hypertrophy of the ventricular myocardial cells continues, it begins to have poor contractility, requires more oxygen to perform, and has poor circulation from the coronary arteries. This can result in heart tissue ischemia and lead into cardiac dysrhythmias (Lewis et al. 2014, 768).

Pulmonary hypertension is a lung disorder. The arteries that carry blood from the heart to the lungs become narrowed, making it very hard for the blood to get through the vessels, this then causes the pressure in the arteries to increase more than usual (high blood pressure). Scientists think that the procedure starts with injury to the layer of cells that line the small blood vessels of the lungs.

et al. 2017). Pulmonary hypertensions occurs in about 8-23% of premature infants (Vyas-Read S et. al. 2017). One method of determine if a patient has pulmonary arterial hypertension is by lung function test (Davis R and Mychaliska G, 2013). One current method used to help treat pulmonary arterial hypertension is assisted ventilation, the method helps lower blood pressure (Davis R and Mychaliska G, 2013). However assisted ventilation can not be used in all preterm infants some extracorporeal life support which will provide respiratory and veno-arterial support (Davis R and Mychaliska G, 2013).

The increased resistance of blood flow through the pulmonary semilunar valve from the right ventricle backs up the pressure of blood

Right ventricular hypertrophy is where the muscle of the right ventricle is thicker than usual and causes the heart to work harder than normal to move blood through the narrowed pulmonary valve.

Long-term hypertension can result in a variety of consequences. These consequences are the result of the heart having to adapt and work harder, i.e. against an increased afterload due to the increased systolic pressure. The heart adapts via hypertrophy of the smooth muscle. Chronic hypertension can also lead to a disruption of the endothelium, thus increasing the

Right pulmonary artery has normal arborization, capillary and levophase. Except in the atelectatic area of the right upper lobe where the distal branches seem to be crowded as expected.

Pulmonary embolism (PE) accounts for up to 30,000 deaths each year. (Beckman, 2014). It has been estimated that nearly one-third of deaths stemming from pulmonary embolism occur within the first hour. (Muckart, 2010). It can prove to be extremely difficult to diagnose pulmonary embolism due to the wide range of symptoms and presentations, or lack there of. (Muckart, 2010; Tarbox & Swaroop, 2013). Some patients with acute pulmonary embolism, possibly as many as 50%, are completely asymptomatic. (Muckart, 2010). Although the clinical presentation can vary dramatically, some of the main symptoms include tachycardia, sub-sternal chest pain, dyspnea, hypoxemia, hypotension and even possibly shock. (Tarbox & Swaroop, 2013). There are several risk factors attributed to PE, including but not limited to, recent immobilization, previous myocardial infarction or cerebral vascular accident, prior surgery or recent trauma. (Tarbox & Swaroop, 2013). Initial symptoms primarily present with severe respiratory distress, but the main adverse effects of PE effect the cardiovascular system due to the fact that the embolus causes an occlusion in the pulmonary vasculature. (Muckart, 2010). The obstruction within the pulmonary artery vastly increases vascular resistance, which results in right ventricular failure; therefore the left ventricular preload is minimized and cardiac output collapses. (Muckart, 2010).

Firstly, the hemodynamics model centers around the heart as a pumping organ, utilizing changes in heart rate and stroke volume or both, as explained by Frank and Starling, to respond and adapt to changes in pressure or volume exerted on it, with pathological ventricular remodeling as the compensatory outcome of long-term increases in preload and excessive pressure (Johnson, 2014). Heart rate is up- and down-regulated by the sympathetic, respectively parasympathetic nervous system, and stroke volume is controlled by preload, the blood volume in the ventricles right before systole, by afterload, the ejection force determined from systemic vascular resistance and ventricular wall tension, and by the contractile ability of the heart muscle (Porth, 2015). The contractility of the actin and myosin filaments is dependent on adenosine triphosphate (ATP) as energy source and on intracellular calcium release, and the diffusion of extracellular calcium ions across L-type calcium channels mediated through beta-adrenergic receptors to signal the chemical reaction leading to muscle shortening, as well as the removal of calcium through cell-membrane pumps to avoid signal overload (Porth, 2015). Pressure and volume overload will lead to ventricular hypertrophy, myocardial stiffness, restricted stroke volume, ventricular dilation and further

The pulmonary vasculature contains arteries and arterioles, which branch in the lungs to create a dense capillary bed to provide blood flow. The pulmonary capillary bed is a high-volume, low-pressure, low-resistance system that delivers blood to and from the lungs via the arterial and venous circulation systems. The right ventricle of the heart is responsible for pumping blood to the pulmonary artery and to the lungs so it can be oxygenated while the left ventricle pumps oxygenated blood to the tissues. Typically, hypertension refers to high blood pressure in the systemic circulation, however, an increase in blood pressure may also occur in pulmonary circulation. The pulmonary artery supplying blood to the lungs can become narrowed,

Congestive heart failure (CHF) is a weakness of the heart that has an insufficient circulation of blood throughout the body, which leads to the build-up of fluid in the lungs and edema in the surrounding tissues of the body. “As the intravascular pressure increases along with the amount of extravascular liquid, the lungs become less compliant and less permeable to oxygen, leading to respiratory discomfort (dyspnea), hypoxemia and tachypnea” (Garcia and Wright, 2010). As the condition deteriorates, the capacity of the interstitial space is exceeded, the fluid floods the alveoli and airways resulting in full blown CPE, an acute respiratory distress and a major medical emergency in heart failure patients” (Guyton 1991). There are two types of

Pulmonary edema is excessive fluid in the lungs. The fluid accumulates in several air sacs in the lungs causing dyspnea. Heart problems can lead to pulmonary edema, but the accumulation of fluid can be caused by several things such as medications, injury to the chest cavity, among other things (Mayo Clinic Staff).

Nurse Vincent M. Vacca, Jr. aptly described in this issue of the Nursing Journal the significance of early detection and health management of people who are or are maybe suffering from Pulmonary Arterial Hypertension. He described PAH as a condition wherein a patient is having a mean pulmonary arterial (PA) pressure of greater than 25 mm

Pulmonary Fibrosis is a condition where the lung tissue becomes thick and scarred, but it is more serious than just thinking you have scarring on your lungs. The thickening and scarring of the lungs makes it hard for the oxygen supply to be delivered throughout the body. This disease can develop slowly or quickly and can stay the same for years. Pulmonary fibrosis occurs in a variety of clinical settings, is a major cause of mortality, and represents an enormous medical need. However, the disease is heterogeneous and the failure to distinguish different types of fibrosing lung diseases can lead to inaccurate treatments. Pulmonary fibrosis occurs in the context of connective tissue diseases that are often characterized by a distinct pattern

Symptoms of pulmonary hypertension do not usually occur until the condition has progressed. The first symptom of pulmonary hypertension is shortness of breath with everyday activities, such as climbing stairs. Fatigue, dizziness, and fainting spells can also be symptoms. Swelling in the abdomen, ankles or legs, bluish lips and skin, and chest pain may occur as strain on the heart increases. Symptoms range