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Introduction to Critical Care Nursing in Cardiac Surgery

Presented by Kim Duong-Coburn

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Learning Objectives

Summarize indications for cardiac surgery

Analyze principles of cardiopulmonary bypass

Apply preload, afterload, contractility concepts to achieve optimal cardiac output/index

Identify interventions to achieve hemodynamic stabilities using nursing critical thinking processes,

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Looking back…

1892 Rehn in Frankfurt, Germany successfully repaired a L V stab wound with 3 sutures.

1925 Souttar performed digital exam mitral valve on a beating heart via L chest wall incision on a 15 y/o who had severe mitral stenosis.

1935 Beck rerouted the IMA to the surface of the heart to provide a collateral vascular bed on a 48 y/o coal miner suffering from debilitating cardiac pain.

1949 Bailey pioneered valve commisurotomy to treat mitral stenosis.

1954 John Gibbon from Philadelphia used “mechanical heart lung machine” on 18 y/o Cecilia BaVolek to repair her atrial septal defect.

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Cardiopulmonary Bypass

Principles of Cardiopulmonary Bypass:

Hemodilution
Hypothermia
Anticoagulation

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A=venous reservoir & blood filter

B=membrane oxygenator

C= heat exchanger coil

Cardiopulmonary Bypass Components

D= CPB console

E=cardioplegia reservoir

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Cannulation

Venous blood is drained into the oxygenator through 1-2 cannulas from R atrium ( or vena cava)

Arterial blood is returned via a single cannula in the ascending aorta

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Indications for Cardiac Surgery

CABG (coronary artery bypass grafting)
Valve repair / replacement
Thoracic aneurysm repair
Surgical management of arrhythmia
TMR (transmyocardial laser revascularization)
Ventricular reconstruction
Removal of myxoma
Surgical correction for congenital heart diseases
Insertion of ventricular assist device
Cardiac transplantation

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CABG

Successful grafts typically last 8-15 years.
Younger patients with no complicating disease_better prognosis.
Cognitive decline postop_multiple factors (CPB, hypoxia, high/low body T, hyper/hypotension, arrhythmia)
Long term lifestyle modification, control BP, cholesterol, DB.

The choice of conduits is highly dependent upon the particular surgeon and institution. Typically, the left internal thoracic artery (LITA) (previously referred to as left internal mammary artery or LIMA) is grafted to the left anterior descending) is grafted to the left anterior descending artery and a combination of other arteries and veins is used for other coronary arteries. The right internal thoracic artery (RITA), the great saphenous vein) is grafted to the left anterior descending artery and a combination of other arteries and veins is used for other coronary arteries. The right internal thoracic artery (RITA), the great saphenous vein from the leg and the radial artery) is grafted to the left anterior descending artery and a combination of other arteries and veins is used for other coronary arteries. The right internal thoracic artery (RITA), the great saphenous vein from the leg and the radial artery from the forearm are frequently used; in the U.S., these vessels are usually harvested endoscopically, using a technique known as endoscopic vessel harvesting) is grafted to the left anterior descending artery and a combination of other arteries and veins is used for other coronary arteries. The right internal thoracic artery (RITA), the great saphenous vein from the leg and the radial artery from the forearm are frequently used; in the U.S., these vessels are usually harvested endoscopically, using a technique known as endoscopic vessel harvesting (EVH). The right gastroepiploic artery) is grafted to the left anterior descending artery and a combination of other arteries and veins is used for other coronary arteries. The right internal thoracic artery (RITA), the great saphenous vein from the leg and the radial artery from the forearm are frequently used; in the U.S., these vessels are usually harvested endoscopically, using a technique known as endoscopic vessel harvesting (EVH). The right gastroepiploic artery from the stomach) is grafted to the left anterior descending artery and a combination of other arteries and veins is used for other coronary arteries. The right internal thoracic artery (RITA), the great saphenous vein from the leg and the radial artery from the forearm are frequently used; in the U.S., these vessels are usually harvested endoscopically, using a technique known as endoscopic vessel harvesting (EVH). The right gastroepiploic artery from the stomach is infrequently used given the difficult mobilization from the abdomen.

CABG associated

Postperfusion syndromePostperfusion syndrome (pumphead), a transient neurocognitive impairment associated with cardiopulmonary bypassPostperfusion syndrome (pumphead), a transient neurocognitive impairment associated with cardiopulmonary bypass. Some research shows the incidence is initially decreased by off-pump coronary artery bypass, but with no difference beyond three months after surgery. A neurocognitive decline over time has been demonstrated in people with coronary artery disease regardless of treatment (OPCAB, conventional CABG or medical management). However, a 2009 research study suggests that longer term (over 5 years) cognitive decline is not caused by CABG but is rather a consequence of vascular disease.^[32]

NonunionNonunion of the sternumNonunion of the sternum; internal thoracic artery harvesting devascularizes the sternum increasing risk.

Myocardial infarctionMyocardial infarction due to embolism, hypoperfusion, or graft failure.

Late graft stenosisLate graft stenosis, particularly of saphenous veinLate graft stenosis, particularly of saphenous vein grafts due to atherosclerosisLate graft stenosis, particularly of saphenous vein grafts due to atherosclerosis causing recurrent anginaLate graft stenosis, particularly of saphenous vein grafts due to atherosclerosis causing recurrent angina or myocardial infarction.

Acute renal failure due to embolism or hypoperfusion.

Stroke, secondary to embolism or hypoperfusion.

Vasoplegic syndrome, secondary to cardiopulmonary bypass and hypothermia

Grafts last 8 – 15 years, and then need to be replaced.

Pneumothorax: An air collection around the lung that compresses the lung

Hemothorax: Blood in the space around the lungs

Pericardial TamponadePericardial Tamponade: Blood collection around the heart that compresses the heart and causes poor body and brain perfusion. Chest tubesPericardial Tamponade: Blood collection around the heart that compresses the heart and causes poor body and brain perfusion. Chest tubes are placed around the heart and lung to prevent this. If the chest tubesPericardial Tamponade: Blood collection around the heart that compresses the heart and causes poor body and brain perfusion. Chest tubes are placed around the heart and lung to prevent this. If the chest tubes become clogged in the early post operative period when bleeding is ongoing this can lead to pericardial tamponadePericardial Tamponade: Blood collection around the heart that compresses the heart and causes poor body and brain perfusion. Chest tubes are placed around the heart and lung to prevent this. If the chest tubes become clogged in the early post operative period when bleeding is ongoing this can lead to pericardial tamponade, pneumothoraxPericardial Tamponade: Blood collection around the heart that compresses the heart and causes poor body and brain perfusion. Chest tubes are placed around the heart and lung to prevent this. If the chest tubes become clogged in the early post operative period when bleeding is ongoing this can lead to pericardial tamponade, pneumothorax or hemothorax.

Pleural EffusionPleural Effusion: Fluid in the space around the lungs. This can lead to hypoxia which can slow recovery.

Postop AF

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Valvular Heart Disease

Stenosis vs. regurgitation

Repair vs. replacement

Biological vs. mechanical valve

Anticoagulation therapy for prosthetic valve Type of valve Antithrombotic therapy Duration Mechanical Valve

Mechanical prosthetic valve Warfarin or Nicoumalone�Target INR 2.5 to 3.5 life long Mechanical valve + Systemic embolism / dilated LA/depressed LV function / chronic AF As above + Aspirin 100-160 mg per day or Dipyridamole 100 mg TDS life long Mechanical Prosthetic valve and high risk of bleeding Warfarin or Nicoumalone �Target INR of 2-3 life long Tissue Valve

Bioprosthetic (mitral or aortic) Warfarin or Nicoumalone �Target INR of 2-3 3 months Bioprosthetic + Chronic AF or atrial thrombus As above long term Bioprosthetic with system embolism As above 1 year Uncomplicated bioprosthetic after first 3 months Aspirin 325 mg per day life long

www.heartonline.org/Coronary%20Bypass%20Surge...

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Heart Valves

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�Mitral Stenosis

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Postop Care

“all postop cardiovascular patients are considered unstable during the first 6 hours unless proven otherwise”

(Cabral et al. Manual of Postoperative Management in Adult Cardiac Surgery)

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Postop Care

5 “headaches”

Hypothermia
Hypovolemia
Hypotension
Hypertension
Hemorrhage

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Hypothermia

Rewarming: T raised to 36-37 C before end of CPB
After drop: 45 min postop in CCU
Overshoot: 8-12 hrs postop, up to 38.3 C
Shivering
Rewarm acidosis: “wash out” of lactic acid
Rewarming shock

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Hypovolemia

Volume replacement: crystalloid,colloids,blood products

Frequent causes= hemmorhage,diuresis, third spacing

Compensatory responses to hypovolemia= increase SVR, increase HR, increase myocardial contractility, shifting fluid into intravascular compartment

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Hypotension

Volume replacement: albumin, LR, blood products
Inotropic supports
Prevention of warming shock
Control postop hemorrhage
Treat warming acidosis
Improve cardiac measures

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Hypertension

Paroxymal postop hypertension: immediate postop to 4-6 hrs after
Parameters: SBP>130-160, DBP>90-100, MAP>90-110 mmHg
Intervention: pharmacology support, correct hypoxia/hypercapnia, adequate volume
Nipride metabolized into cyanogen which is converted to thiocyanate in liver, excreted by kidney

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Hemmorhage

Sequalae of CPB on coagulation
Systemic Inflammatory Response Syndrome
Bleeding 3ml/kg/hr
Keep SBP 90-100, MAP 60-65 unless hx CVA, carotid disease
Peep at 10 cm if CO,CI adequate
Auto transfusion
Blood products and pharmacolgical support

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Other consideration

Goal = maintain adequate tissue perfusion to prevent end organ failure
Keep adequate CO,CI (pace,preload,afterload,contractility)
Maintain adequate elctrolyte
Prevent arrhythmia
Tight control hyperglycemia
Early extubation as tolerated

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Cardiac output

CO = a measure of the amount of blood that is ejected by the heart each minute.
SV = represents the amount of blood that is ejected from the LV with one contraction.
CO = SV X HR

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Cardiac output

SV is influenced by amount of blood in the ventricle and the force of contraction by the ventricle.

SV also affected if aortic valve restricted the outflow of the LV

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Ejection fraction (EF)

EF = is the percentage of the volume of the LV that is ejected with each contraction.

Normal EF = 65-70%

EF reflects the efficiency of LV to pump blood forward into the systemic circulation

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Hemodynamic Parameters	Formula	Normal Ranges
Cardiac Output CO CI	HR X SV CO/BSA	4-8 L/min 2.5-4 L/min./m2
Preload Indicators CVP Wedge LA		2-6 mmHg 8-12 mmHg 4-12 mmHg
Afterload Indicators PVR SVR	(PAM-PAWPX80)/CO (MAP-CVPX80)/CO	37-250 dynes/sec/cm5 800-1200 dynes/sec/cm5
Contractility Indicators SI (Stroke Volume Index) RVSWI LVSWI	SV/BSA (PAM-CVP)SV x 0.0136/BSA (MAP-PAD)SVx0.0136/BSA	33-47 cc/m2/beat 7-12 g/m2/beat 38-85g/m2/beat

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Key Concepts in Measuring CO

Accuracy depend on functioning tricuspid, no ventricular septal defect,and a stable rhythm

Correlate CI with a tissue oxygenation parameter (Svo2(60-70%),lactate(1-2 mEQ/L), pH(7.35-7.45),HCO3 (22-26 mEQ/L)

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