Perfusion Tech I Midterm

American Society of Extracorporeal Technology (AmSECT)

Founded in 1964

American Board of Cardiovascular Perfusion (ABCP)

Protects the public through establishment and maintenance of CVP standards

American Academy of Cardiovascular Perfusion

Incorporated in 1979

Accreditation Committee - Perfusion Education (AC-PE)

Consists of 14 members appointed by its 7 sponsor organizations

Michael DeBakey

Developed medical roller pump in 1930s for blood circulation

Chargaff and Olson

Demonstrated in 1937 that protamine sulfate neutralizes heparin

May 6, 1953

First successful open heart operation using CPB performed by John Gibbon

Walt Lillehei

Performed the first successful controlled cross-circulation operations using human donor parents in the 1950s

Robert DeWall

Developed the inexpensive bubble oxygenator for CPB in the 1950s

Jay McLean

Discovered heparin as an anticoagulant

Wilfred Bigelow

Demonstrated that hypothermia could safely lengthen tolerated circulatory arrest time

3/16”

Venous line inner diameter for a patient < 4kg

1/4”

Venous line inner diameter for a patient 4-15 kg

3/8”

Venous line inner diameter for a patient 15-70kg

1/2”

Venous line inner diameter for a patient >70kg

Clear polycarbonate

Rigid, non-wettable plastic used to manufacture transparent circuit connectors

Fluted or barbed connections

Placed on circuit connectors to create a tight connection that prevents blood leakage when exposed to positive pressure

Polyvinyl chloride (PVC) tubing

Preferred for CPB due to its durability under continuous mechanical roller compression

Spallation

Mechanical breakdown and release of microparticles from inner tubing walls caused by roller pump compression

Durometer

Measures material hardness of circuit materials

open hard-shell venous reservoir advantages

Allows electronic level monitoring, integrates cardiotomy return, and allows entrained venous air to rise up and out

open hard-shell venous reservoir disadvantages

Larger blood-air interface and increased risk of pumping air to patient when volume runs low

Closed soft-shell venous reservoir

Utilizes a pliable plastic bag that collapses when empty under negative pressure, preventing air entry into pump. Capacity = 1000 - 3000mL

Closed soft-shell venous reservoir disadvantages

Cannot process cardiotomy suction return or defoam aspirated blood, so they require a separate hard-shell cardiotomy reservoir. Cannot support vacuum assist due to collapsability

air removal from closed soft-shell reservoir

Must be manually purged through stopcocks at the top of the bag

Aortic cross-clamp

Isolates the heart by blocking systemic blood entry and keeping cardioplegia solution confined to coronary circulation

Antegrade cardioplegia cannula

Inserted into the aortic root proximal to the cross-clamp

Retrograde cardioplegia cannula

Positioned in the coronary sinus

LV vent

Removes residual blood to prevent left ventricular distension

Aortic root vent

Evacuates pooled blood and air from the aortic root

2-stage cavoatrial venous cannula

Inserted through the RA appendage into IVC

indications for bicaval over 2-stage cavoatrial cannulation

Need for a completely bloodless field on the right side of the heart

Arterial cannula

Usually the narrowest portion of the extracorporeal circuit

Roller pump

Positive-displacement flow is determined by pump RPM, tubing inner diameter, and raceway contact length

importance of proper occlusion

Over-occlusion causes hemolysis and spallation while under-occlusion causes internal backflow

Centrifugal pump

Relies on an in-line flow meter to measure delivery as its flow is afterload-dependent and not directly proportional to pump rotation speed

One-way check valve or flow-interlocked safety device

Safety feature that must be incorporated downstream of a centrifugal pump to prevent retrograde flow

Gravity venous drainage

Determined by central venous pressure (CVP), height differential between patient and reservoir, and line resistance

Chattering or fluttering of venous line

Caused by excessive negative pressure causing vein walls to collapse around cannula tip

Correction of venous line chattering

Partially clamp venous line, add circulating volume, or administer vasoconstrictors

Air lock in gravity venous drainage line

Accumulation of air in the venous line cancels the siphon effect and stops drainage

Kinetic-assisted vs Vacuum-assisted venous drainage

KAVD utilizes a mechanical centrifugal pump in the line while VAVD applies regulated negative pressure to a hard-shell reservoir

Max negative pressure for VAVD

-60 to -100 mmHg

Bubble transgression

When vacuum is applied without active blood flow, air is pulled across the oxygenator membrane into the blood path

Max acceptable pressure gradient across an arterial cannula at peak flow

100 mmHg

Dispersion or diffusion cannula tips

Mitigate the jetblasting effect of a small arterial cannula

Alternate aortic cannulation sites

Femoral, axillary, subclavian, or innominate arteries

2 locations for bubble detector - Gravlee

Between reservoir and pump, or between oxygenator outlet and arterial filter

Cardiotomy suction

Primary source of microemboli because it gets intense contact with atmospheric air, tissue debris, and mechanical shear forces

Hollow-fiber membrane oxygenator

Has replaced bubble and film oxygenators in modern CPB

standard blood sampling port positioning

Venous blood is sampled pre-oxygenator and arterial blood is sampled post-oxygenator

Left atrial or proximal to distal aorta bypass

Procedures that are arterial-to-arterial bypasses using only a pump for distal flow

indications for peripheral cannulation

Pre-sternotomy bypass, aortic surgery, minimal access surgery, or ECMO

John Gibbon’s 1937 prototype HLM

Used a vertical rotating cylinder that formed a thin film of blood exposed to oxygen

Dr. Charles Hufnagel

Developed the plastic ball valve implanted into the descending aorta to treat aortic insufficiency in 1951

Dr. Charles Bailey

Performed the first recorded cardiac valve surgery in 1940

Dr. Albert Starr

Developed the caged-ball mechanical heart valves series

Increasing internal diameter

Reduces flow resistance and pressure gradients but increases circuit prime volume

In-line hemoconcentrator

Removes excess fluid and plasma water via ultrafiltration to raise HCT during CPB

epiaortic probe

Used with TEE to directly examine the ascending aorta for atheroma before cannulation

1972 and 1973

AmSECT administered the first certification examinations to practicing perfusionists

1975

Responsibility for administering perfusion certification exams transferred from AmSECT to ABCP

Azygos principle

Resting body functions can be maintained on dramatically reduced blood flow (10% of normal) supplied solely by the azygos vein while both the superior and inferior venae cavae are temporarily occluded. Applied by Lillehei to cross-circulation

M-number

Describes the pressure-flow performance characteristics of a cannula

fetal circulation shunts

specialized structures diverting blood away from the non-functional high-resistance fetal lungs and liver

foramen ovale

Interatrial opening allowing oxygenated blood from the placenta to shunt directly from RA to LA. Closes after birth to form fossa ovalis

Ductus arteriosus

Vascular conduit connecting PA trunk to descending aorta. Closes after birth to form ligamentum arteriosum

Ductus venosus

Vascular shunt directing oxygenated blood from the placenta, past the liver, directly into the IVC.

Azygos venous system

Venous network running along posterior chest wall that drains the thoracic cavity, abdominal walls, esophagus, bronchi, and trachea directly into SVC

Circle of willis

arterial ring at the base of the brain connecting anterior and posterior cerebral circulations, allowing collateral blood flow between L and R hemispheres during bypass or localized occlusion

coronary dominance

Based on which artery gives rise to the posterior descending artery (PDA/posterior interventricular branch). Majority of the population = right

sinus venarum

smooth-walled posterior region of RA where SVC, IVC, and coronary sinus enter, separated from the anterior pectinate muscle ridges by the crista terminalis

cardiac conduction

SA node, posterior middle & anterior internodal tracts, Bachmann’s bundle (LA), Bundle of His (AV), L and R bundle branches, purkinje fibers (accessory fibers or subendocardial branches)

median sternotomy

Standard approach for open heart surgery - vertical midline incision through the sternum from sternal notch to xiphoid process

reciprocating sternal saw

Fwd/bkwd blade motion featuring a guarded toe piece for opening virgin sternums from bottom to top

oscillating sternal saw

Side to side spinning blade used for redo sternotomies. Cuts through bone without grabbing retrosternal adhesions or old grafts

arterial conduits for CABG

LIMA/RIMA (internal mammary) or radial artery. Offer higher long-term patency

venous conduits for CABG

greater saphenous vein (SVG)

end-to-side anastomosis

joins the end of a bypass conduit to the side of the target vessel

side-to-side anastomosis

Sequential grafting method allowing one continuous conduit to bypass multiple lesions on the same vessel branch

aortic dissection

Tear in the aortic intima allowing pressurized blood to separate wall layers and form a false lumen

Stanford A/B classification of aortic dissection

A involves ascending aorta, B involves descending aorta distal to the L subclavian artery

DeBakey I/II/III classification of aortic dissection

I involves ascending, arch, and descending aorta, II involves ascending only, III involves descending only

aortic aneurysm

Abnormal, permanent dilation of aortic wall exceeding 50% of normal diameter. Surgery indicated when diameter exceeds 5 cm

Karl Landsteiner

Discovered human ABO blood groups in 1901

Charles Lindbergh & Alexis Carrel

Mechanically designed and built a glass organ perfusion pump in 1935 that kept harvested organs viable for up to 21 days

Werner Forssman

Performed the first cardiac catheterization on himself in 1929 by inserting a urethral catheter through his arm vein into RA

Dwight Harken

Pioneered intracardiac surgery during WWII by removing shell fragments and bullets from inside heart chambers

Rene Favaloro

Pioneered and popularized the routine use of saphenous vein grafts for CABG in 1967

Christiaan Barnard

Performed the first successful human-to-human heart transplant in 1967

Denton Cooley

Implanted the first Total Artificial Heart (TAH) into a human in 1969