Advanced Nursing ConceptsPart 1: Hemodynamic Monitoring

Sandra Lewis, ARNP-BC-ADM

What Comes First? The PATIENT!!! View the patient first, the

equipment is merely an adjunct.

Anatomical review http://www.blaufuss.org/tutorial/#

Go to Start tutorial

Cardiovascular System Review Heart- pumps blood forward through the

vasculature Arteries- carry oxygenated blood from the

heart to the body. (Constriction and Dilation regulate the blood flow delivered)

Capillaries-microscopic vessels that allow for exchange of gases, nutrients and metabolic waste between plasma and the body cells

Hemodynamics Basic tenet is the control of adequate

oxygen delivery to the tissues. Interrelationship of various dynamic

forces that affect the blood’s circulation through the body.

Knowledge of pressure, flow and resistance provide the foundation of understanding.

Continued… The ability to anticipate

hemodynamic deterioration or detect adverse changes early is a major factor in preventing hemodynamic crisis, thus the major reason for hemodynamic monitoring.

Indications for Hemodynamic Monitoring Dehydration Hemorrhage GI Bleed Burns Surgery Acute MI Cardiomyopathy

Shock: all types: septic, cardiogenic, neurogenic, anaphylactic

Congestive Heart Failure

Cont.. Veins return deoxygenated blood to the heart.

About 70% of circulating blood volume is in the venous system at any one time.

Blood has both a cellular and fluid component. About 60% of blood is plasma. The remainder consists of RBC’s, WBC’s,

platelet’s. ERYTHROCYTES make up about 99% OF THE

CELLULAR COMPONENTS AND ARE RESPONSIBLE FOR OXYGEN TRANSPORT.

An increase in RBC’s increases viscosity of blood. Increased viscosity makes blood flow through

smaller vessels more difficult.

Pressure, Flow and Resistance Basic physics law:Pressure=Flow X Resistance

Pressure=the force exerted Blood Flow= the amount of fluid

moved per unit of time Resistance=the opposition to force

or flow (influenced by the size, length and viscosity of the fluid)

Cardiac Cycle Both the atria and the ventricles have

filling phases (diastole) and contraction phases (systole)

During diastole the left and right ventricles receive blood from the atria

During systole the ventricles squeeze blood from the heart to the aorta and the pulmonary artery. See figure 7.4 p.131

Atrial Kick Final contraction of the atrium

filling the ventricle…

Preload Left ventricular end-diastolic VOLUME. The VOLUME left in the ventricle when the

mitral valve closes determines the amount of blood ejected into the systemic circulation. The ventricle never ejects its entire volume…just a portion of it…usually 60-70%( this is the EF..(ejection fraction)

The volume of blood EJECTED with each beat is referred to as Stroke Volume (SV).

Arterial Blood FlowArterial blood pressure=measure of

force exerted on the arterial walls by the blood

Afterload =The pressure or resistance of

blood flow out of the ventricle. So, if arterial BP is high, the left

ventricle must exert more force to pump blood out effectively…this increases myocardial oxygen requirements.

Contractility A measure of how forcefully the

ventricle contracts to eject its volume.

It is the intrinsic ability of the muscle fibers to shorten.

Systemic Vascular Resistance (SVR) THE major factor that influences

SVR is the lumen (diameter) of the vessel.

This is an important concept, often in the critical care setting, medications are used to alter the lumen size of systemic vessels (primarily the arterioles).

Hemodynamic Monitoring Equipment All contain: a transducer, monitor,

and fluid filled catheter, tubing and flush system

Swan-Ganz Cath Normally has four ports (can have another

proximal lumen for fluids or medication infusion)

The thermistor lumen is used to measure cardiac output.

The proximal port is used to measure right atrial pressure

Distal lumen measures pulmonary artery pressure

The balloon port has a special 1.5 ml syringe connected…this is used to measure PCWP

Functions of the Catheter Continuous hemodynamic

monitoring, assessing vascular tone, myocardial contractility, and fluid balance.

Measures PAP, CVP, and allows hemodynamic calculations. Cardiac output can be determined using thermodilution.

Transvenous pacing

Complications of a Swan/Ganz Infection Dysrhytmias Air Embolism Pulmonary thromboembolism Pulmonary artery rupture Pulmonary Infarction See table 7-1 p. 147

Arterial Monitoring An invasive technique for

monitoring arterial blood pressure. Preferred in unstable patients

because it is accurate and continuous

Allen's test

A test for integrity of the radial and ulnar arteries at the wrist. The examiner compresses the patient's radial and ulnar arteries at the wrist. The patient is then asked to open and close the hand rapidly until the palm appears white. The examiner then releases either the radial or the ulnar artery and looks for return of pink color and circulation to the hand. The test is then repeated releasing the other artery. The hand should return to its pink color within 6 seconds if circulation through that artery is adequate.

Indications for arterial Monitoring Patients requiring frequent ABG’s

or lab work Patients with low flow states,

hypotensive Patients with severe hypertension Patients with severe

vasoconstriction or vasodilation.

Arterial Lines Placed in an artery, usually the

radial, but can use femoral, or brachial.

Connected to a pressurized source Complications include: thrombosis,

embolism, blood loss, infection Tubing and transducer replaced

every 96 hours.

Continued, Caveats Invasive monitoring is more accurate Invasive BP should by higher than cuff BP If cuff BP is higher look for equipment

malfunction or technical error A dampened wave form can indicate a

move toward hypotension…an immediate cuff pressure should be obtained

Nursing Implications Prevent or reduce the potential for

complications. Maintain 300mmHg on bag Maintain continuous flow through tubing Aseptic dressing change Sterile caps on openings Change tubing q 96 hrs. 5 min hold on discontinued site

Arterial Measurements The systolic pressure is measured

at the peak of the waveform. See fig. 7-10 p137 This pressure reflects the function

of the left ventricle. NORMAL value=100-130 mmHg

The LOWEST point on the waveform represents the end diastolic pressure.

This pressure reflects systemic resistance.

Normal diastolic pressure is 60-90 mmHg

Dicrotic notch The small notch on the downstroke

of the wave form. It represents the closure of the

aortic valve. This is the reference point between

the systolic and diastolic phases of the cardiac cycle.

Mean Arterial Pressure/MAP Is a calculated pressure that closely

estimates the perfusion pressure in the aorta and its branches.

It represents the average systemic arterial pressure during the ENTIRE CARDIAC CYCLE.

Normal MAP = 70-100 mmHg MAP MUST be maintained above 60 for

the major organs to perfuse.

CVP/ Right Atrial Pressure Monitoring A direct measure of the right atrium

pressure Clinical significance: REFLECTS RIGHT

VENTRICULAR DIASTOLIC PRESSURE Abnormalities in RAP are caused by

conditions that alter venous tone, blood volume, or right ventricular contractility

Cont… Low RAP indicates hypovolemia

that may be attributed to dehydration, acute blood loss, extreme vasodilation (as in sepsis)

High RAP indicates severe vasoconstriction, fluid overload, pulmonary hypertension