Absite topic PA

Nir Hus

Pulmonary Artery Flow-directed Catheter (Swan-Ganz)

Measurements obtainedPulmonary arterial Pressure(PAP)Pulmonary Capillary Wedge Pressure(PCWP)Central Venous Pressure(CVP)Cardiac Output measurementMixed Venous Blood gas measurementSaturation of venous oxygen

concentrations(SVO2)

Anatomy of the Catheter

Pulmonary Artery Flow-directed Catheter (Swan-Ganz)

four lumens proximal lumen-located in the right atrium and is

used for infusion of drugs or fluids as indicated per patient’s status. May also be used for CVP monitoring

Distal Lumen-lies in the pulmonary artery when correctly positioned and is used to monitor PA pressures, withdraw mixed venous blood specimens and deliver fluids.

Pulmonary Artery Flow-directed Catheter (Swan-Ganz) The distal lumen is also surrounded by

a balloon connected to an external valve via a second lumen. The balloon inflation has 2 purposesto allow moving blood to float the

catheter forward during insertionto allow measurement of PCWP

Pulmonary Artery Flow-directed Catheter (Swan-Ganz) Pulmonary artery pressure-systolic, diastolic and mean

pressures are usually monitored when a PA line is in place. PA measurement is obtained at the end of expiration of the Pt. so the intrathoracic pressure changes do not cause changes in the measurement

May measure systolic or diastolic Systolic-20-30’s diastolic 5-12

PAD-Referred to as Pulmonary artery diastolic pressure PAWP-Pulmonary artery wedge pressrue=PCWP

Are sensitive indicators of fluid volume status and cardiac function.

Thermodilution Cardiac Output Cardiac output-monitored in patients who are

hemodynamically unstable. Usually the PA catheter is used to measure CO

Thermodilution technique is often used-a known amount of solution(saline or d5w) of known temperature(room or chilled) is injected rapidly into the right atrial lumen of the PA catheter. A drop in blood temp is detected by a thermister embedded in the catheter tip in the pulmonary artery.

CO is then calculated by a computer from the temperature waveform

Normal CO should be 4-8 l/min CI-cardiac index = CO divided by BSA CO or CI will be decreased in hypovolemia, shock, heart

failure Increases may be associated with sepsis prior to septic shock

Mixed venous oxygen saturation

PA catheters have a sensor located on them which measures oxygen saturation of hemoglobin of pulmonary artery blood which is mixed venous blood

Normal SVO2 at rest is 60-80% Blood gases may also be drawn from the

PA line to determine mixed venous blood gas analysis and SVO2

Floating the Swan

Flush all ports, check balloon and zero Once catheter tip is passed the introducer

check pressure tracing and inflate balloon While watching the waveforms advance the

catheter smoothly The catheter is advanced until a PA “wedge”

is obtained (approximately 40-60 cm)

Floating the Swan

a wave – is the pressure wave seen in the jugular vein, as a result of the backward flow of blood produced after atrial contraction

c wave – depicts the pressure in the jugular as a result of the tricuspid valve closing after ventricular systole

x descent – occurs just after the c wave, and it depicts a significant drop in jugular pressure as a result of ventricular contraction and early atrial filling

v wave – is jugular pressure resulting from back-pressure from right atrial filling, occurring in late systole or in early diastole

y descent – follows the v wave and is a result of the tricuspid valve opening and passive filling of the ventricle

Measured Variables

Mean arterial blood pressure Heart rate Mean right atrial pressure Systolic and diastolic pulmonary artery

wedge pressures Cardiac output

Calculated Variables

Cardiac index Stroke index Systemic vascular resistance Pulmonary vascular resistance Left and right ventricular systolic work

index

Normal Cardiac Hemodynamics (Adult)

Pressure site Systolic pressure

Diastolic pressure

Mean Pressure

R atrium 0 – 8 mmHg

R ventricle 5 – 30 mmHg 0 – 8 mmHg

Pulmonary artery

15 – 30 mmHg 5 – 15 mmHg 10 – 18mmHg

Pulmonary art wedge

1 – 12mmHg

L ventricle 90 – 140 mmHg 2 – 12mmHg

Aorta 90 – 140 mmHg 60 – 90mmHg 70 – 105mmHg

Normal Cardiac Hemodynamics (Adult)

Fisk CO CO 3.5 – 8.5 L/min CI 2.5 – 4.5 L/min/sq m

Vascular resistance SVR 640 - 1200 dyne-sec-cm PVR 45 -120 dyne-sec-cm

Valve gradients Aortic <10 mmHg Mitral Negligible

Valve area Aortic 2.0 - 3.0 sq cm Mitral 4.0 - 6.0 sq cm

EF 40 – 60 %

Oxygen Parameters

Parameter Normal RangePartial pressure of arterial O2 (PaO2) 80-100 mm Hg

Partial pressure of arterial CO2 (PaCO2)

35-45 mm Hg

Bicarbonate (HCO3) 22-28mEq/L

pH 7.38-7.42

Arterial oxygen saturation (SaO2) 95-100%

Mixed venous saturation (SvO2) 60-80%

Oxygen consumption (VO2) 200-250 ml/min

Oxygen consumption index 120-160 ml/min/m sq

Principal Indications for Swan-Ganz Catheter Acute myocardial infarction Acute left ventricular failure Shock Cardiac tamponade Pulmonary embolism Acute respiratory failure Cardiac surgery

Hypotension

Hypovolemic Cardiogenic Vasogenic

Low CVP High CVP Low CVP

Low CI Low CI High CI

High SVR High SVR Low SVR

Shock

Heart Failure Cardiogenic

High CVP High CVP

Low CI Low CI

High SVR High SVR

Normal VO2 Low VO2

Right Atrial Pressure

Abnormally lowTrue hypovolemia (hemorrhage)Relative hypovolemia (vasodilators)Negative intrathoracic pressure

Pulmonary Artery Wedge Pressure Abnormally low

Identical to those listed for right atrial pressure (low)

True hypovolemia (hemorrhage)Relative hypovolemia (vasodilators)Negative intrathoracic pressure

Pulmonary Artery Wedge Pressure Abnormally high

True or relative hypervolemia Systolic or diastolic left ventricular dysfunction Hindrance to left atrial emptying Mitral regurgitation Cardiac tamponade Constrictive pericarditis Positive intrathoracic pressure Venous occlusive disease

Cardiac Output

Three main methods of measurementFlick method Indicator-dilution methodAngiographic method

Flick Method The principal is that the amount of oxygen

extracted by the lungs from air is equal to the amount taken up by blood in its passage through the lungs. Therefore, by measuring the rate of lung oxygen extraction and the oxygen content of the pulmonary arterial and pulmonary venous blood, the rate of pulmonary blood flow can be calculated. Unless there is a shunt, pulmonary blood flow equals cardiac output.

The Indicator-dilution Technique

Is based on the principle that the dilution of an indicator is proportional to the volume of fluid to which it is added

If the amount and concentration of an indicator is known the volume of fluid in which it is diluted can be calculated

There are several specific indicator methods available, however, until several years ago, only two were used clinically. The most common is the thermodilution method.

Cardiac Output (High)

Acute Acute hypervolemia ARDS, severe pneumonia Septic shock Drugs Acute intoxications Fever, heat stress, malignant hyperthermia Anxiety, emotional stress Delirium tremens (DT’s)

Cardiac Output (High)

Chronic Severe chronic anemia Cirrhosis Chronic renal failure Pregnancy Thyrotoxicosis Polycythemia vera Labile hypertension Congenital heart disease (PDA)

Cardiac Output (Low)

Acute Acute hypovolemia (absolute or relative) Acute severe pulmonary hypertension Acute myocardial pump failure

extensive MI myocardial toxic injury (ethanol, CO poisoning, septic shock) Following cardiopulmonary bypass

Acute impairment of ventricular filling Increased intrathoracic pressure Cardiac tamponade Stunned myocardium Acute ischemia

Cardiac Output (Low)

AcuteArrhythmias

Sustained VT Extreme bradycardia

Acute inotropic changes in a failing myocardium Beta-blockers Ischemia Acidosis

Cardiac Output (Low)

Chronic Chronic severe pulmonary hypertension Chronic myocardial pump failure

Ischemia Hypertensive or dilated cardiomyopathy Severe valvular heart disease

Chronic impairment of ventricular filling Constrictive pericarditis Restrictive cardiomyopathy Mitral or tricuspid stenosis Atrial myxoma

Vascular Resistance

Factors affecting blood-flow within the vascular treeFrictionTurbulent flowPulsatile flowVessel elasticity

Systemic Vascular Resistance (SVR) Most useful in the management of

critically ill patients with shock

Cardiac Tamponade

Fluid accumulation in the pericardium causes elevation of intrapericardial pressure and a decrease in the transmural pressure of all four cardiac chambers

Abnormally high and equalized right atrial pressure and pulmonary wedge pressures

Heart rate increases Cardiac output decreases

Treatment of Cardiac Tamponade Evacuation of pericardial fluid

PericardiocentesisMedian sternotomy

Shunts

Demonstrated by a absence of an expected pressure difference

With a significant ASD the left and right mean atrial pressures are within 5 mm of Hg. of one another

With VSD’s the ventricular pressures may also equilibrate

Shunts

Evaluation of shunts requires:DetectionClassificationLocalizationQuantitation

Left to Right Shunts

Characterized by two basic abnormalitiesMixing of saturated (systemic arterial or

pulmonary venous) with desaturated (systemic venous or pulmonary arterial) blood on the right side of the circulation

Increased pulmonary blood-flow relative to the systemic blood-flow

Right to Left Shunts

Characterized by two basic abnormalitiesMixing of desaturated (systemic venous or

pulmonary arterial) with saturated (systemic arterial or pulmonary venous) blood on the left side of the circulation, thus creating a oxygen step-down

Decreased pulmonary blood flow relative to systemic blood flow

Complications Associated With venipuncture Accidental arterial puncture Pneumothorax Gas embolism Hemothorax Chylothorax

Complications Associated With Catheter Insertion Arrhythmias Knots Injury to the tricuspid or pulmonary valve Cardiac tamponade

Q1- Conditions necessary for PA pressure to equal L. atrial pressure include all of the following except

A. High levels of positive end-expiratory pressure are being delivered

B. PA pressure is greater than alveolar pressure

C. Pulmonary venous pressure is greater than alveolar pressure

D. PA cath is wedged.

Q2- Before accurate pressure can be obtained with PA cath., the pressure transducer must be calibrated and zeroed to the level of the:

A. R. atrium

B. R. ventricle

C. Main PA

D. L. atrium

Q3 - Most common complication associated w/ the passage of a PA cath is:

A. Development of dysrhythmia

B. Hematoma at entry site

C. Knotting in R. ventricle

D. PTX

Q4 – All of the following values can be derived from direct measurment during blood-gas analysis EXCEPT:

A. Arterial blood oxygen tension (Pao2)

B. Arterial hemoglobin oxygen saturation (Sao2)

C. Mixed venous blood oxygen tension (Pvo2)

D. Mixed venous hemoglobin oxygen saturation (Svo2)

E. Cerebral oxygen consumption (Cvo2)

Q5 - The oxyhemoglobin dissociation curve is shifted to the Left by:A. Decrease blood pH

B. Increased erythrocyte 2,3-diphosphoglycerate (DPG) concentration

C. Increased body temp

D. Methemoglobinemia

E. Carboxyhemoglobinemia

Q6 - The oxyhemoglobin dissociation curve is shifted to the Right by:A. Decrease blood pH

B. Increased H+ concentration

C. Increased erythrocyte 2,3-DPG

D. Increased body temp

E. Rising PCo2

Q7 – A Swan ganz cath in a 70 kg male was placed through the Left subclavian vein and a wedge pressure is obtained. The approximate distance into the pt. should be?

A. 45cm

B. 50cm

C. 55cm

D. 60cm

Q8 – Which sample of blood will have the lowest O2 tension

A. Coronary sinus

B. Femoral vein

C. Portal vein

D. Renal vein

Q9 – Which sample of blood will have the highest O2 tension

A. Coronary sinus

B. Femoral vein

C. Portal vein

D. Renal vein