MANAGEMENT OF PATIENTS WITH COMPLICATIONS FROM HEART DISEASES

CARDIAC HEMODYNAMICS

Cardiac Output – is the amount of blood pumped out of the heart in 1 minute.Stroke Volume – the amount of blood pumped out of the ventricle with each contraction

FACTORS THAT REQUIRE HEMODYNAMIC MONITORING

Preload – the amount of myocardial stretch just before systole caused by the volume of blood presented to the ventricle. Venous return – the volume of blood that enters the

ventricle Compliance - the elasticity or the amount of “give”

when blood enters the ventricle. Afterload – the amount of resistance to ejection of

blood from a ventricle Contractility – the force of ventricular contraction;

related to the status of myocardium.

The determinants of stroke volume.

The SV is determined by the amount of preload presented to the ventricle, the amount of afterload or resistance to ventricular ejection, and the strength of cardiac contractility.

NONINVASIVE ASSESSMENT OF CARDIAC HEMODYNAMICS

1. Measuring jugular venous distention – estimates right ventricular preload

2. Positive hepatojugular test – identifies elevated left ventricular preload

3. Mean arterial blood pressure - an approximate indicator of left ventricular afterload

4. Activity tolerance – may be used as an indicator of overall cardiac functioning.

JUGULAR VENOUS DISTENTION POSITIVE HEPATOJUGULAR TEST

Mean arterial blood pressure

where:

•is cardiac output•is systemic vascular resistance•is central venous pressure

INVASIVE ASSESSMENT OF CARDIAC HEMODYNAMICS

Pulmonary artery catheter - is diagnostic procedure used to detect heart anomalies, monitor therapy, and evaluate the effects of drugs.- It allows direct, simultaneous measurement of pressures in the right atrium, right ventricle, pulmonary artery, and the filling pressure ("wedge" pressure) of the left atrium.

PULMONARY ARTERY CATHETER

AD…

CARDIAC ARREST

- Occurs when the heart ceases to produce an effective pulse and circulate blood.

- It may be caused by a cardiac electrical event such as ventricular fibrillation, progressive profound bradycardia, or when there is no heart rhythm at all (asystole).

- It may follow respiratory arrest

- It may also occur when electrical activity is present but there is ineffective cardiac contraction or circulating volume, called pulseless electrical activity (PEA).

- PEA can be caused by hypovolemia, hypoxia, hypothermia, hyperkalemia, massive pulmonary embolism, myocardial infarction and medication overdose.

CAUSES OF CARDIAC ARREST

CLINICAL MANIFESTATIONS

Loss of consciousness, pulse and BP Ineffective respiratory gasping may

occur The pupils of the eyes begin dilating

within 45 sec Seizures may or may not occurTake note:

For adult and child: carotid pulse is assessed

For infant: brachial pulse is assessed

EMERGENCY MANAGEMENT

Cardiopulmonary resuscitation (CPR)- Provides blood flow to vital organs until effective

circulation can be re-established.

- It consists of the following steps:1. Airway – maintaining an open airway.2. Breathing – providing artificial ventilation by

rescue breathing3. Circulation – promoting artificial circulation by

external cardiac compression; administer medication therapy.

4. Defibrillation with standard defibrillator or autonomic external defibrillator (AED) for ventricular tachycardia and ventricular fibrillation.

MEDICATIONS USED IN CPR1. Oxygen – improves tissue oxygenation

and corrects hypoxemia. Nursing considerations:

• Use 100% FiO2 during resuscitation.• Recognize that no lung damage

occurs when used for less than 24 hours.

• Monitor dose by pulse oximeter.

2. Epinephrine (Adrenalin) – increases systemic vascular resistance and blood pressure; improves coronary and cerebral perfusion and myocardial contractility.

Nursing considerations:• Administer 1 mg every 3 – 5 minutes by IV

push or through the ET tube.• Avoid adding to IV lines that contain

alkaline solution (eg. Bicarbonate)

3. Vasopressin (Pitressin) – increases systemic vascular resistance and BP

Nursing considerations:• Give 40 U IV one time only

4. Atropine – blocks parasympathetic action; increases SA node automaticity and AV conduction.

Nursing considerations:• Give rapidly as 2.0 to 2.5 mg IV push or

through the ET tube• Be aware that less than 0.5 mg in the adult

can cause the heart rate to decrease to a worse bradycardia.

• Monitor patient for reflexive tachycardia.

5. Sodium bicarbonate (NaHCO3) – corrects metabolic acidosis.

Nursing considerations:• Administer initial dose of 1 mEq/kg IV; then

administer the dose based on the base deficit calculated from arterial blood gas values.

• Recognize that to prevent development of rebound metabolic alkalosis, complete correction of acidosis is not indicated.

6. Magnesium – promotes adequate functioning of the cellular sodium-potassium pump.

Nursing considerations:• May give diluted over 1 – 2 minutes or

IV push.• Monitor for hypotension, asystole,

bradycardia, respiratory paralysis.