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Pregnancy Induce Hypertension Case Study

Posted: 07 Mar 2010 10:10 PM PST

Introduction:

Pregnancy Induced Hypertension (PIH) is a condition in which vasospasms occur during pregnancy in both small and large arteries. Signs of hypertension, proteinuria, and edema develop. It is unique to pregnancy and occurs in 5% to 7% of pregnancies in the united states. Despite years of research, the cause of the disorder is still unknown. Originally it was called toxemia because researchers pictured a toxin of some kind being produced by a women in response to foreign protein of the growing fetus, the toxin leading to the topical symptoms. No such toxins have ever been identified.

A condition separate from chronic hypertension, PIH tends to occur most frequently in women of color or with a multiple pregnancy; primiparas are younger than 20 years of age or older than 40 years, women from low socio economic backgrounds, those who have an underlying disease such as heart disease, diabetes with vessel or renal involvement and essential hypertension.

PIH is classified as gestational hypertension, mild preeclampsia, severe preeclampsia and eclampsia, depending on how far development advances. Gestational hypertension when develops an elevated blood pressure but has no proteinuria or edema. Perinatal mortality is not increased with simple gestational hypertension, so no drug therapy is necessary; and blood pressure returns to normal after birth. Mild preeclampsia when blood pressure rises to 140/90 mmHg or systolic pressure elevated 15 mmHg above pregnancy level; mild edema in upper extremities or face. Severe preeclampsia when blood pressure has risen to 160 mmHg systolic and 110 mmHg diastolic; proteinuria; pulmonary or cardiac involvement; extensive peripheral edema; hepatic dysfunction; theombocytopenia. Eclampsia is the most severe classification of PIH and seizure or coma Accompanied by s/s of preeclampsia. Any woman who falls into one of the high-risk categories for PIH should be observed carefully for symptoms at prenatal visits. She needs instructions about what symptoms to watch for so she can alert her clinician if additional symptoms occur between visits.

Anatomy and Physiology:

When most people hear the term cardiovascular system, they immediately think of the heart. We have all felt our own heart "pound" from time to time, and we tend to get a bit nervous when this happens. The crucial importance of the heart has been recognized for a long time. However, the cardiovascular system is much more than just the heart, and from a scientific and medical standpoint, it is important to understand why this system is so vital to life.

Most simply stated, the major function of the cardiovascular system is transportation. Using blood as the transport vehicle, the system carries oxygen, nutrients, cell wastes, hormones, and many other substances vital for body homeostasis to and from the cells. The force to move the blood around the body is provided by the beating heart. The cardiovascular system can be compared to a muscular pump equipped with one-way valves and a system of large and small plumbing tubes within which the blood travels.

HEART:

The heart is a muscular organ found in all vertebrates that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions.
The heart is enclosed in a double-walled sac called the pericardium. The superficial part of this sac is called the fibrous pericardium. This sac protects the heart, anchors its surrounding structures, and prevents overfilling of the heart with blood. It is located anterior to the vertebral column and posterior to the sternum. The size of the heart is about the size of a fist and has a mass of between 250 grams and 350 grams. The heart is composed of three layers, all of which are rich with blood vessels. The superficial layer, called the visceral layer, the middle layer, called the myocardium, and the third layer which is called the endocardium. The heart has four chambers, two superior atria and two inferior ventricles. The atria are the receiving chambers and the ventricles are the discharging chambers. The pathway of blood through the heart consists of a pulmonary circuit and a systemic circuit. Blood flows through the heart in one direction, from the atrias to the ventricles, and out of the great arteries, or the aorta for example. This is done by four valves which are the tricuspid atrioventicular valve, the mitral atrioventicular valve, the aortic semilunar valve, and the pulmonary semilunar valve.
Systemic circulation is the portion of the cardiovascular system which carries oxygenated blood away from the heart, to the body, and returns deoxygenated blood back to the heart. The term is contrasted with pulmonary circulation.

Pulmonary circulation is the portion of the cardiovascular system which carries oxygen-depleted blood away from the heart, to the lungs, and returns oxygenated blood back to the heart. The term is contrasted with systemic circulation. A separate system known as the bronchial circulation supplies blood to the tissue of the larger airways of the lung.

Arteries are blood vessels that carry blood away from the heart. All arteries, with the exception of the pulmonary and umbilical arteries, carry oxygenated blood.

Pulmonary arteries
The pulmonary arteries carry deoxygenated blood that has just returned from the body to the heart towards the lungs, where carbon dioxide is exchanged for oxygen.

Systemic arteries
Systemic arteries can be subdivided into two types – muscular and elastic – according to the relative compositions of elastic and muscle tissue in their tunica media as well as their size and the makeup of the internal and external elastic lamina. The larger arteries (>10mm diameter) are generally elastic and the smaller ones (0.1-10mm) tend to be muscular. Systemic arteries deliver blood to the arterioles, and then to the capillaries, where nutrients and gasses are exchanged.

The Aorta
The aorta is the root systemic artery. It receives blood directly from the left ventricle of the heart via the aortic valve. As the aorta branches, and these arteries branch in turn, they become successively smaller in diameter, down to the arteriole. The arterioles supply capillaries which in turn empty into venules. The very first branches off of the aorta are the coronary arteries, which supply blood to the heart muscle itself. These are followed by the branches off the aortic arch, namely the brachiocephalic artery, the left common carotid and the left subclavian arteries.

Aorta the largest artery in the body, originating from the left ventricle of the heart and extends down to the abdomen, where it branches off into two smaller arteries (the common iliacs). The aorta brings oxygenated blood to all parts of the body in the systemic circulation.

The aorta is usually divided into five segments/sections:

Ascending aorta—the section between the heart and the arch of aorta
Arch of aorta—the peak part that looks somewhat like an inverted "U"
Descending aorta—the section from the arch of aorta to the point where it divides into the common iliac arteries
o Thoracic aorta—the half of the descending aorta above the diaphragm
o Abdominal aorta—the half of the descending aorta below the diaphragm

Arterioles
Arterioles, the smallest of the true arteries, help regulate blood pressure by the variable contraction of the smooth muscle of their walls, and deliver blood to the capillaries.
Veins are blood vessels that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the lungs; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood. Veins differ from arteries in structure and function; for example, arteries are more muscular than veins and they carry blood away from the heart.
Veins are classified in a number of ways, including superficial vs. deep, pulmonary vs. systemic, and large vs. small.

Superficial veins
Superficial veins are those whose course is close to the surface of the body, and have no corresponding arteries.

Deep veins
Deep veins are deeper in the body and have corresponding arteries.

Pulmonary veins
The pulmonary veins are a set of veins that deliver oxygenated blood from the lungs to the heart.

Systemic veins
Systemic veins drain the tissues of the body and deliver deoxygenated blood to the heart.
Atrium sometimes called auricle, refers to a chamber or space. It may be the atrium of the lateral ventricle in the brain or the blood collection chamber of a heart. It has a thin-walled structure that allows blood to return to the heart. There is at least one atrium in animals with a closed circulatory system.

Right atrium is one of four chambers (two atria and two ventricles) in the human heart. It receives deoxygenated blood from the superior and inferior vena cava and the coronary sinus, and pumps it into the right ventricle through the tricuspid valve. Attached to the right atrium is the right auricular appendix.

Left atrium is one of the four chambers in the human heart. It receives oxygenated blood from the pulmonary veins, and pumps it into the left ventricle, via the atrioventricular valve.
Ventricle is a chamber which collects blood from an atrium (another heart chamber that is smaller than a ventricle) and pumps it out of the heart.
Right ventricle is one of four chambers (two atria and two ventricles) in the human heart. It receives deoxygenated blood from the right atrium via the tricuspid valve, and pumps it into the pulmonary artery via the pulmonary valve and pulmonary trunk.

Left ventricle is one of four chambers (two atria and two ventricles) in the human heart. It receives oxygenated blood from the left atrium via the mitral valve, and pumps it into the aorta via the aortic valve.

Pathophysiology of Pregnancy Induced Hypertension (PIH):

Clinical Manifestations:

A. Mild Preeclampsia

BP of 140/90
1+ to 2+ proteinuria on random
weight gain of 2 lbs per week on the 2nd trimester and 1 lb per week on the 3rd trimester
Slight edema in upper extremities and face

B. Severe Preeclampsia

BP of 160/110
3-4+ protenuria on random
Oliguria (less than 500 ml/24 hrs)
Cerebral or visual disturbances
Epigastric pain
Pulmonary edema
Peripheral edema
Hepatic dysfunction

C. Eclampsia is an extension of preeclampsia and is characterized by the client experiencing seizures.

Diagnostic Evaluation:

Based on the presenting symptoms. Often the disease process has been developing and affecting the renal and vascular system
Frequently a sudden weight gain will occur, of 2 lb. or more in 1 week, or 6 lb. or more within 1 month. This often occurs before the edema is present.

Medical Treatment and Evaluation:

Magnesium Sulfate (Pregnancy risk category B)
muscle relaxant, prevent seizures
loading dose 4-6g, maintenance dose 1-2g/h IV
infuse IV dose slowly over 15-30 min.
   •Always administer as a piggy back infusion.
   •Assess PR, urine output, DTR, and clonus every hour.
   •Observe for CNS depression and hypotonia in infant at birth.
Hydrazaline (Apresoline) Pregnancy risk category C
anti hypertensive (peripheral vasodilator) use to decrease hypertension
5-10mg/IV
Administer slowly to avoid sudden fall of BP
•Maintain diastolic pressure over 90 mmHg to ensure adequate placental filling.
Diazepam (Valium) Pregnancy risk category D
halt seizures
5-10mg/IV
administer slowly. Dose may be repeated every 10-15 min. (up to 30mg/hr)
•Observe for respiratory depression for both mother and infant at birth.
Calcium Gluconate (Pregnancy risk category C)
antidote for Magnesium Sulfate
1g/IV (10 mL of a 10% solution)
have prepared at bed side when administering Magnesium Sulfate
administer at 5mL/min.

Complications of PIH:

Intrauterine growth restriction (IUGR) – an abnormally restricted symmetric or asymmetric growth of fetus
Oligohydramnios – abnormally low volume of amniotic fluid
Risk of placental abruption – premature separation of a normally situated placenta from the wall of uterus
Risk of preterm delivery (often iatrogenic) – delivery before 37 weeks of gestation
Coagulopathy
Stillbirth
Seizures
Coma
Renal failure
Maternal hepatic damage
Hemolysis
Elevated liver enzymes levels
Low platelet count (HELLP syndrome)

Nursing Interventions:

Intervention for mild PIH:	Rationale:
1. Assess maternal VS and fetal heart rate.	-to detect any increase which is warning that a women's condition is worsening.
2. Encourage elevation of edematous arms and legs.	-to increase venous blood return.
3. Encourage compliance with bed rest in a lateral recumbent position.	-to increase evacuation of sodium and encouraging diuresis and lateral recumbent position can avoid uterine pressure on the vena cava and prevent supine hypotension syndrome.
4. Provide emotional support.	-this can make a women underestimate the severity of the situation.
5. Support patient with bed rest and darken the room if possible.	-because a bright light can trigger seizures.
6. Obtain daily hematocrit levels as ordered.	-to monitor blood concentration and help to the extent of plasma loss to interstitial space or extent of the edema.
7. Obtain blood studies (CBC, platelets count, liver function, BUN and creatinine, and fibrin degregation).	-to assess for renal and liver function and the development of disseminated intravascular coagulation which often accompanies severe vasospasms.
8. Obtain daily weights at the same time each day.	-to evaluate tissue fluid retention.
9. Raise side rails.	-to help prevent injury if seizure should occur.
10. Support nutritious diet of moderate to high in protein and moderate in sodium.	-to compensate for protein she is losing in her urine.
11. An indwelling catheter may be inserted as ordered.	-to allow accurate recording of output and comparison with intake.
12. Oxygen administration to the mother may be given as ordered.	-to maintain adequate fetal oxygenation and prevent fetal bradycardia.
13. Administer medication for seizures and hypertension episodes as ordered.	-to prevent seizures and hypertension.

Intervention for severe PIH:

Rationale:

1. Maintain patient's airway by not putting a tongue blade between a women's teeth during seizures.

-to prevent broken of teeth which could then be aspirated.

2. Turn a woman on her side.

-to allow secretions to drain from her mouth.

Discharge Plan:

Exercise

encourage patient's on deep breathing exercises.
move extremities when lying.
elevate the head part when sleeping, to promote increase peripheral circulation
encourage overall passive and active exercises program during pregnancy to prevent need for cesarean birth.
exercises like tailor sitting, squatting, kegel exercise, pelvic rocking, and abdominal muscle contraction will promote easy delivery.

Treatment:

use of drugs
catheterization
obtaining labs. (CBC, platelets count, liver function, BUN and creatinine, and fibrin degregation)

Health Teaching:

Encourage patient foe sodium restriction.
Encourage to avoid foods rich in oil and fats.
Encourage patient to limit her daily activities and exercises.

Ongoing Assessment:

Observe carefully for symptoms at prenatal visit.
Give instruction about what symptoms to watch for so she can alert her clinician if additional symptoms occur between visits.

Diet:

low fats and sodium diet, restriction if possible.
high in protein, calcium and iron.
Adequate fluid intake

Sex:

limit sexual activity
sexual intercourse at 2nd trimester should be avoided.

View Nursing Care Plan – Pregnancy Induced Hypertension (PIH)

References:

Maternal and child health nursing by Adele Pillitteri 5th edition;volume 1 page 426-433;page 329-332
All-in-one care planning resource page 748; by Pamela L. Swearlngen, RN
Maternal neonatal nursing;page 30 by Lippincott Williams and Wilkins
Luckman and Sorensen's Medical-Surgical Nursing a Physiologic Approach 4th edition Volume 1 page 734
http://wikipedia.org
http://nursingcrib.com

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Pathoyphysiology of Pregnancy Induced Hypertension (PIH)

Posted: 07 Mar 2010 10:09 PM PST

Preeclampsia is a characterized, by vsospasms, changes in the coagulation system, and disturbances in systems related to volume and BP control. Vasospasms results from an increased sensitivity to circulating pressors, such as angiotensin II, and possibly an imbalance between the prostaglandins prostacyclin and thromboxane A1.

Endothelial cell dysfunction, believed to result from decreased placental perfusion, may account for many changes in preeclampsia. Arteriolar vasospasm may cause endothelial damage and contribute to an increased capillary permeability. This increase edema and further decreases intravascular volume, predisposing the woman with preeclampsia to pulmonary edema.

Immunologic factors may play an important role in the development of preeclampsia. The presence of a foreign protein, the placenta, or the fetus maybe perceived by the mother's immune system as an antigen. This may then trigger an abnormal immunologic response. This theory is supported by the increased incidence of preeclampsia or eclampsia in first-time mothers or to multiparous woman pregnant by a new partner. Preeclampsia maybe an immune complex disease in which the maternal antibody system is overwhelmed from excessive fetal antigens in the maternal circulation. This theory seems compatible with the high incidence of preeclampsia among women exposed to a large mass of trophoblastic tissue as seen in twin pregnancies or hydatidiform moles.

Genetic predisposition maybe another immunologic factor. Dekker reported a greater frequency of preeclampsia and eclampsia among daughters and granddaughters of women with a history of eclampsia, which suggests an autosomal recessive gene controlling the maternal immune response. Paternal factors are also examined.

Diets in inadequate nutrients, especially protein, calcium, sodium, magnesium, and vitamin E and C, maybe an etiologic factor in preeclampsia. Some practitioners prescribed high-protein diets (90 mg supplemental protein) without caloric restriction and moderate sodium intake in the prevention and treatment of this disorder. However, data are limited regarding the association between diet and preeclampsia.

Preeclampsia progress along a continuum from mild disease to severe preeclampsia, HELLP syndrome, or eclampsia. The pathophysiology of preeclampsia reflects alteration in the normal adaptations of pregnancy. Normal physiologic adaptations to pregnancy include increase blood plasma volume, vasodilation, and decreased systemic vascular resistance, elevated cardiac output, and decreased colloid osmotic pressure. Pathologic changes in the endothelial cells of the glomeruli are uniquely characteristic of preeclampsia, particularly in nulliparous women. The main pathogenic factor is not an increase in BP but poor perfusion as a result vasospasm. Arteriolar vasospasm diminishes the diameter of blood vessels, which impedes blood flow to all organs and raises BP. Function in organs such as the placenta, kidneys, liver and brain is deceased by as much as 40% to 60%.