Hemodynamics Basic Concepts 1204053445109897 4
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Transcript of Hemodynamics Basic Concepts 1204053445109897 4
Understanding AdultHemodynamicsTheory, Monitoring, Waveforms and MedicationsVicki Clavir RN
PurposeThe primary purpose of invasive hemodynamic monitoring is the early detection, identification, and treatment of life-threatening conditions such as heart failure and cardiac tamponade. By using invasive hemodynamic monitoring the nurse is able to evaluate the patient's immediate response to treatment such as drugs and mechanical support. The nurse can evaluate the effectiveness of cardiovascular function such as cardiac output, and cardiac index.
Objectives Understands basic cardiac anatomy
Verbalizes determinates of Cardiac Output and their relationships to each other
List indications for hemodynamic monitoring
Demonstrates monitor system and set up
Describe pharmacologic strategies that manipulate the determinates of cardiac output
Indications for Hemodynamic Monitoring:One of the obvious indications for hemodynamic monitoring is decreased cardiac output. This could be from dehydration, hemorrhage, G. I. bleed, Burns, or surgery. All types of shock, septic, cardiogenic, neurogenic, or anaphylactic may require invasive hemodynamic monitoring. Any deficit or loss of cardiac function: such as acute MI, cardiomyopathy and congestive heart failure may require invasive hemodynamic monitoring.
Coronary ArteriesRCA-RA, RV&LV Inf,Inf SeptumSA node 65%AV node 80%PDA 80-90%CX-LA,LV (side/back)SA node 40%AV node 20%LAD LV (front/bottom)SeptumBundle branches Left Main
Cardiac Cycle Diastole Phase
Early DiastoleVentricles relax. Semilunar valves close. Atrioventricular valves open. Ventricles fill with blood.Mid DiastoleAtria and Ventricles are relaxed. Semilunar valves are closed. Atrioventricular valves are open. Ventricles continue to fill with blood.Late DiastoleSA node contracts. Atria contract. Ventricles fill with more blood. Contraction reaches AV node.
Cardiac Cycle Systole Phase
SystoleContraction passes from AV node to Purkinje fibers and ventricular cells. Ventricles contract. Atrioventricular valves close. Semilunar valves open. Blood is pumped from the ventricles to the arteries.
Electrical Conduction systemSA node Atrial muscleInternodal fibers AV node AV bundle right and leftbundle branchesVentricular muscle
Autonomic Nervous SystemThe autonomic nervous system stimulates the heart through a balance of sympathetic nervous system and parasympathetic nervous system innervations.The sympathetic nervous system plays a role in speeding up impulse formation, thus increasing the heart rateThe parasympathetic nervous system slows the heart rate.
The Cardiac Cycle
Coronary Arteries FillThe Cardiac Cycle
The Cardiac Cycle
The Cardiac Cycle
Normal CO 4-8 litersNormal Cardiac Index is 2.5 to 4.5 liters
Heart Rate Works with Stroke VolumeCompensatoryTachycardia BradycardiaDysrhythmias
Factors Causing Low Cardiac Output Inadequate Left Ventricular FillingTachycardia Rhythm disturbanceHypovolemiaMitral or tricuspid stenosisPulmonic stenosisConstrictive pericarditis or tamponade Restrictive cardiomyopathy Inadequate Left Ventricular EjectionCoronary artery disease causing LV ischemia or infarctionMyocarditis, cardiomyopathyHypertension Aortic stenosisMitral regurgitation Drugs that are negative inotropes Metabolic disorders
Hemodynamic termsPreload- Stretch of ventricular wall. Usually related to volume. (how full is the tank?) Frank Starlings Law
Hemodynamic termsIncreased preload seen in Increased circulating volume (too much volume)Mitral insufficiencyAortic insufficiencyHeart FailureVasoconstrictor use- (dopamine)Decreased Preload seen inDecreased circulating volume (bleeding,3rd spacing)Mitral stenosis Vasodilator use ( NTG)Asynchrony of atria and ventricles
Normal Value - 2-8 mm Hg
Or LVEDPPAOP = 8-12 mm Hg PAD = 10-15 mm Hg
Hemodynamic termsContractility-How well does the ventricular walls move? How good is the pump? Decreased due toDrugs certain drugs will decrease contractilityLido, Barbiturates, CCB, Beta-blockersInfarction, CardiomyopathyVagal stimulationHypoxia
Hemodynamic termsContractility- IncreasedPositive inotropic drugsDobutamine, Digoxin, EpinephrineSympathetic stimulationFear, anxietyHypercalcemia ( high calcium)
CONTRACTILITY - PRECAUTIONS
Do Not use Inotropes until volume deficiency is corrected
Correct Hypoxemia and electrolyte imbalance.
Hemodynamic termsAfterload resistance the blood in the ventricle must overcome to force the valves open and eject contents to circulation.
Hemodynamic termsFactors that increase afterload areSystemic resistance or High Blood pressureAortic stenosis Myocardial Infarcts / CardiomyopathyPolycythemia Increased blood viscosity
Hemodynamic termsFactors that decrease AfterloadDecreased volumeSeptic shock- warm phaseEnd stage cirrhosisVasodilators
Normal PVR is 120 to 200 dynes
Normal SVR - 800-1200 dynes
Mean Arterial PressureMAP is considered to be the perfusion pressure seen by organs in the body.It is believed that a MAP of greater than 60 mmHg is enough to sustain the organs of the average person under most conditions.If the MAP falls significantly below this number for an appreciable time, the end organ will not get enough blood flow, and will become ischemic.Calculated MAP = 2x diastolic + systolic 3
1.PRELOAD-venous blood return to the heart Controlled by;.Blood Volume PRBCs Albumin Normal Saline Diuretics- lasix,bumex Thiazides Ace inhibitors . Venous Dilation Nitroglycerine Ca+ channel blockers clonidine (Catapress) methyldopa trimethaphan (arfonad) Dobutamine Morphine2. CONTRACTILITY-forcefulness of contractilityCa+ channel blockersDigoxinDopamine/DobutamineMilrinone/amrinone3.AFTERLOAD work required to open aortic valve and eject blood resistance to flow in arteries Dopamine (at higher doses) Ace inhibitors Nipride/lesser extent Nitro Calcium channel blockers LabetalolDrugs of Hemodynamics4. HEART RATE Beta blockersCalcium channel blockers Atropine Dopamine Dobutamine
O2 O2 O2O2O2O2O2ToBODYFrom Body
Factors that make up SVO2 are Cardiac output SaO2 VO 2 (oxygen consumption) Hemoglobin
Causative FactorsClinical Conditions O2 Delivery Hb concentration- Anemia- HemorrhageOxygen saturation (SaO2)- Hypoxemia Lung disease Low FIO2 Cardiac Output- LV dysfunction (cardiac disease, drugs)- Shock cardiac/septic (late) Hypovolemia Cardiac Dysrhythmias Oxygen consumption Fever, infection Seizures, agitation Shivering Work of Breathing Suctioning, bathing, repositioning
Increased SVO2Most common cause is - Sepsis
Wedged PA catheter
Functions of PA Catheter Allows for continuous bedside monitoring of the following Vascular tone, myocardial contractility, and fluid balance can be correctly assessed and managed.Measures Pulmonary Artery Pressures, CVP, and allows for hemodynamic calculated values. Measures Cardiac Output. (Thermodilution) SvO2 monitoring (Fiber optic). Transvenous pacing. Fluid administration.
PA CatheterKEEP COVEREDKEEP LOCKEDYELLOWClearBLUEREDMarkings on catheter. 1. Each thin line= 10 cm. 2. Each thick line= 50 cm.
Description of PA Catheter Ports/lumens.
CVP Proximal (pressure line - injectate port for CO)-BLUE PA Distal (Pressure line hook up)- Yellow Extra port - usually- ClearThermistor Red Cap
Continuous Cardiac Output and SVO2 monitoring
Indications for PA catheterThe pulmonary artery catheter is indicated in patients whose cardiopulmonary pressures, flows, and circulating volume require precise, intensive management.MI cardiogenic shock - CHFShock - all typesValvular dysfunctionPreoperative, Intraoperative, and Postoperative MonitoringARDS, Burns, Trauma, Renal Failure
PRESSURE TRANSDUCER SYSTEMS SET UP
500 ml Premixed Heparinized bag of NS
PHLEBOSTATIC REFERENCE POINT
Re-level the transducer with any change in the patients positionReferencing the system 1 cm above the left atrium decreases the pressure by 0.73 mm HgReferencing the system 1 cm below the left atrium increases the pressure by 0.73 mm Hg
Remove cap and keep sterileTurn stopcock towards pressure bagZero monitorReplace cap
SQUARE WAVE TEST- Determines the ability of the transducer to correctly reflect pressures.- Perform at the beginning of each shiftABC
Thermodilution Cardiac OutputsCardiac Outputs reading should be within .5 of each other for averaging purposes.
Except in patients with atrial fibrillation- just average 3 to 4 readings. (due to loss of atrial kick output changes from minute to minute)
Cardiac Outputs should be obtained at the end of respiration - at the same point each time
RN magazine April, 2003 - PA catheter refresher course.
ALL PA measurements are calculated at end expiration because the lungs are at their most equal -(negative vs. positive pressures)
a, c,& v Waves and their Timing to the ECG tracing