Basic Hemodynamic Monitoring(Nurses Concept)

Muhammad Asim RanaBSc, MBBS, MRCP, MRCPS, EDIC, SF-CCM, FCCP

Intensive Care MedicineKing Saud Medical City

You said patient is the most important !

Objectives

• Review:– purposes of Hemodynamic Monitoring– indications for Hemodynamic Monitoring– Biological sensors and monitoring– Pulse oximetry– Automated blood pressure devices– Arterial, central venous, and pulmonary artery

catheters– Cardiac output and oxygen delivery variables

• Mrs. A. a 76 yrs old female with a previous history of congestive heart failure, is admitted with clinical and laboratory evidence of a urinary tract infection. Referred to ICU because of shock state.

► Goals– Confirm diagnosis – Initiate treatment– Monitor for

improvement or worsening in her condition

• What is shock?• How to treat the shock?• How to monitor?

Shock and its types• Failure to deliver and/or

utilize adequate amounts of Oxygen

• Types – Hypovolemic Shock– Cardiogenic Shock– Distributive Shock– Obstructive Shock

Circulation & Oxygen transport

Hemodynamics

• Hemodynamics are the forces which circulate blood through the body.

• Specifically, hemodynamics is the term used to describe the intravascular pressure and flow that occurs when the heart muscle contracts and pumps blood throughout the body.

Hemodynamic monitoring

refers to measurement of pressure, flow and oxygenation of blood within the cardiovascular system. ORUsing invasive technology to provide quantitative information about vascular capacity, blood volume, pump effectiveness and tissue perfusion.

OR Hemodynamic monitoring is the measurement and

interpretation of biological sytems that describes the performance of cardiovascular system

Purpose of monitoring

• Early detection, identification and treatment of life threatening conditions such as heart failure and cardiac tamponade.

• Evaluate the patient’s immediate response to treatment such as drugs and mechanical support.

• Evaluate the effectiveness of cardiovascular function such as cardiac output and index.

Indications

All types of shock:– Cardiogenic shock – Distributive shock – Obstructive shock– Hypovolemic shock

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Types of Hemodynamic Monitoring

• Non-invasive = clinical assessment & NBP• Direct measurement of arterial pressure• Invasive hemodynamic monitoring

►Continuous vs. intermittent►Invasive vs. noninvasive►Never therapeutic but may be diagnostic

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Noninvasive Hemodynamic Monitoring

• Noninvasive BP

• Heart Rate, pulses

• Mental Status

• Mottling

• Skin Temperature

• Capillary Refill

• Urine Output

• Pulse Oxymetry

Pulse Oxymetry

• Estimates Oxyhemoglobin as SpO2• Target SpO2 > 92%• Heart rate displayed should be same as pulse

rate captured by the probe

Oxyhemoglobin Saturation Curve

Oximeter Sensors

Pulse OximetrySources of error

• Physiological/ anatomical• Vasoconstriction• Poor perfusion• Abnormal hemoglobin• Skin pigmentation• Cold extremities• External causes• Motion artifact• Excessive external light

Automated Blood Pressure measuring devices

• Intermittent measurements • Appropriate cuff size necessary• Less accurate during hypotension, arrhythmias

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Proper Fit of a Blood Pressure Cuff

• Width of bladder = 2/3 of upper arm

• Length of bladder encircles 80% arm

• Lower edge of cuff approximately 2.5 cm above the antecubital space

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Why A Properly Fitting Cuff?

• Too small causes false-high reading

• Too LARGE causes false-low reading

Back to our patient

• Patient was persistently hypoxic, hypotensive so electively intubated and ventilated.

• What would you like to do for better monitoring of your patient ?

• Inotropes requirement is increasing.

• Oxygen requirement is varying.

Invasive BP monitoring

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Invasive Arterial Blood Pressure Monitoring

• Indications

• Frequent titration of vasoactive drips

• Unstable blood pressure

• Frequent ABGs or labs

• If unable to obtain Non-invasive BP

• Sites– Radial artery– Brachial artery– Femoral– Dorsalis pedis artery

• Complications– Hematoma/blood loss– Thrombosis– distal ischemia– Arterial injury– Infection

Tubing and transducer should be replaced every 96 hours.

Supplies to Gather

• Arterial Catheter• Pressure Tubing• Pressure Cable• Pressure Bag• Flush – 500cc NS

• Sterile Gown • Sterile Towels • Sterile Gloves• Suture (silk 2.0)• Chlorhexidine Swabs• Mask

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Leveling and Zeroing

• Leveling – Before/after insertion– If patient, bed or transducer

move

• Zeroing – Performed before insertion

& readings

• Level and zero at the insertion site

• Phlebostatic Axis

•Re-level the transducer with any change in the patient’s position

•Referencing the system 1 cm above the left atrium decreases the pressure by 0.73 mm Hg•Referencing the system 1 cm below the left atrium increases the pressure by 0.73 mm Hg

Angles 45°

30°

0°

Importance of zeroing

Arterial pressure measurement• The systolic pressure is

measured at the peak of the waveform.

• 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

Important Concepts

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.

Dampening

Dampening

Dampening and Flush test

Underdampening

Normal Dampening

Invasive BP monitoring

• 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

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Documentation

• Insertion procedure note

• Arterial BP readings as ordered

• Neurovascular checks every two hours(in musculoskeletal assessment of HED)

• Pressure line flush amounts (3ml/hr)

• Tubing and dressing changes

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

Let’s see our patient

• Arterial BP being monitored.

• Fluid challenge given• Inotropes and

vasopressors support augmented.

• Physician asked for CVP & Mixed venous oxygen saturation….

• What is mixed venous oxygen saturation?

• Difference between SVO2 and ScVO2

• How to measure them?• Concept of cardiac

pressures and management strategies

Central Venous Pressure

• Indications– Measure central venous pressure– Access for resuscitation– Selected drug administration– Placement of pulmonary artery catheter

• Complications– Hematoma/vessel injury/blood loss– Pneumothorax/hemothorax– Cardiac arrhythmias– Infection

Central Venous catheter position

Central Venous catheter position

Central venous pressure measurement

Patient position & transducer level

Factors affecting CVP waves

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

• CVP is measured at end expiration

Right Atrial Pressure MonitoringIndications

• Measure right atrial pressure (RAP)• Same as Central Venous Pressure (CVP)

• Assess blood volume; reflects preload to the right side of the heart

• Assess right ventricular function• Infusion site for large fluid volume• Infusion site for hypertonic solutions

Reasons for elevated RA pressure:

• decreased right (or single) ventricle compliance

• tricuspid valve disease

• Intravascular volume overload

• cardiac tamponade

• tachyarrhythmia

Right Atrial PressureMean: 1 to 7 mm Hg

Reasons for reduced RA pressure:

• low intravascular volume status

• inadequate preload

Right Atrial PressureMean: 1 to 7 mm Hg

Right Atrial Pressure MonitoringComplications

• Pneumothorax• Hemothorax• Hemorrhage• Cardiac tamponade• Vessel, RA, or RV

perforation

• Arrhythmias• Air embolism• Pulmonary embolism• Thromboembolism• Infection

Right Atrial Pressure MonitoringWaveform Analysis

• a wave: rise in pressure due to atrial contraction• x decent: fall in pressure due to atrial relaxation• c wave: rise in pressure due to ventricular contraction and

closure of the tricuspid valve• v wave: rise in pressure during atrial filling• y decent: fall in pressure due to opening of the tricuspid valve

and onset of ventricular filling

Right Atrial Pressure MonitoringWaveform Analysis

• Elevated RAP• RV failure• Tricuspid regurgitation• Tricuspid stenosis• Pulmonary hypertension• Hypervolemia• Cardiac tamponade• Chronic LV failure• Ventricular Septal Defect• Constrictive pericarditis

• Decreased RAP• Hypovolemia• Increased contractility

Nursing HOURLY assessment:

1. Air in line or stopcocks 2. Precipitates3. Leaking at site4. Increasing resistance5. Condition of entrance sites

Dressing change policy at LPCHArterial line prn (when seal is broken, wet, old blood, etc)Non-tunneled CVC Q 7 days & prn (Tegaderm & biopatch)Tunneled CVC Q7 days & prn (Tegaderm & biopatch)Intracardiac catheter Q 7 days & prn (Tegaderm & biopatch)

Our patient Mrs A.

• The CVP > 12• FiO2 requirement has

increased.• ScVO2 < 50%• Physician has concern

about cardiac status.• Need to distinguish

between cardiogenic and septic shock…

• Role of cardiac out put in oxygen delivery?

• How to determine the cardiac status?

• Non-invasive – Echo

• Invasive – Swan-Ganz (PAC)– Picco

Some common terminologies…

• Preload• Afterload• Cardiac Output• Cardiac Index• Systemic Vascular

Resistance [SVR]• Pulmonary Vascular

Resistance [PVR]

Understanding basic terms

Preload• Is the degree of muscle fiber

stretching present in the ventricles right before systole

• Is the amount of blood in a ventricle before it contracts; also known as “filling pressures”

• Left ventricular preload is reflected by the PCWP

• Right ventricular preload is reflected by the CVP [RAP]

Afterload• Any resistance against which

the ventricles must pump in order to eject its volume

• How hard the heart [either side left or right] has to push to get the blood out

• Also thought of as the “ resistance to flow” or how “clamped” the blood vessels are

Understanding basic terms

Cardiac output/Index• Is the amount of blood

ejected from the ventricle in one minute

• Two components multiply to make the cardiac output: heart rate and stroke volume [amount of blood ejected with each contraction]

• Cardiac index is the cardiac output adjusted for body surface area (BSI)

Vascular Resistance• Systemic Vascular

Resistance – reflects left ventricular afterload

• Pulmonary Vascular Resistance – reflection of right ventricular afterload

• Many of the drugs we administer will affect Preload, Afterload, SVR/PVR, Cardiac Output

Normal Cardiac Pressures

Concept of right and left sides

Equipment NeededSET-UP FOR HEMODYNAMIC

PRESSURE MONITORING

1. Obtain Barrier Kit, sterile gloves, Cordis Kit and correct swan catheter. Also need extra IV pole, transducer holder, boxes and

cables. 2. Check to make sure signed consent is in chart, and that patient

and/or family understand procedure.3. Everyone in the room should be wearing a mask!4. Position patient supine and flat if tolerated. 5. On the monitor, press “Change Screen” button, then select “Swan Ganz” to allow physician to view catheter waveforms while inserting.6. Assist physician (s) in sterile draping and sterile setup for cordis and swan insertion.

Equipment Needed7. Set up pressure lines and transducers 8. Please level pressure flush monitoring system and transducers to

the phlebostastic axis. Zero the transducers. Also check to make sure all connections are secure.

9. Connect tubings to patient [PA port and CVP port] when physician

is ready to flush the swann. Flush all ports of swann before inserting.10. While floating the swann, observe for ventricular ectopy on the monitor, and make physician aware of frequent PVC’s or runs of VT !11. After swann is in place, assist with cleanup and let patient know

procedure is complete.

Measuring Cardiac output11. Obtain your RA [CVP], PAS/D, PAM, and

wedge. For Cardiac Outputs, inject 10 mLs of D5W

after pushing the start button, repeat X 3. Delete outputs not within 1 point of the mean value.

Can use 0.9% NS instead, but affects the accuracy of the output reading.

12. Before obtaining the cardiac output, please check the computation constant [should read 0.692 for regular yellow swans; 0.692 for SVO2 or blue swanns]

13. Perform hemocalculations (enter today’s height and weight).14. Document findings on the ICU flowsheet.

PA Insertion Waves

Pulmonary Capillary Wedge Pressure (PCWP)• Zero the transducer to the patient’s phlebostatic axis.• Measure the PCWP at end expiration• PCWP should not be higher than PA diastolic• PCWP is an indirect measurement of left ventricular end

diastolic pressure.

Possible Complications• Increased risk of infections – same as with any central venous

lines—use occlusive dressing and Biopatch to prevent• Thrombosis and emboli-- air embolism may occur when the

balloon ruptures, clot on end of catheter can result in pulmonary embolism

• Catheter wedges permanently—considered an emergency, notify MD immediately, can occur when balloon is left inflated or catheter migrates too far into pulmonary artery (flat PA waveform)…can cause pulmonary infarct after only a few minutes!

• Ventricular irritation – occurs when catheter migrates back into RV or is looped through the ventricle, notify MD immediately…can cause VT

Troubleshooting• Dampened waveform –can occur with physical

defects of the heart or catheter; can be caused by kinks, air bubbles in the system, or clots Solution: Check your line for kinks & air bubbles, aspirate (not flush) for clots, straighten out tubing or patient as much as possible

• No waveform – can occur with non-perfusing arrhythmias or line disconnection Solution: Check your line for disconnection, check your patient for pulse, could also be wet transducer or broken cable or box

Back to our patient Mrs A.• A pulmonary artery catheter passed and

following values obtained.RA LA

RV LV

CI and MAP

Impression: Cardiac

• Cardiac Inotropic support added.• Hemoglobin raised to 10.• Mrs. A’s blood pressure responds to further Rx, urine

output improves, mental status returns to normal, and she recovers uneventfully.

Monitoring and therapy based upon information carefully obtained allowed appropriate responses to measured/calculated abnormalities and prevented other inappropriate treatment.

Thank you