FACULTY OF ENGINEERING DEPARTMENT OF BIOMEDICAL ENGINEERING BME
FACULTY OF ENGINEERING DEPARTMENT OF BIOMEDICAL ENGINEERING BME 312 BIOMEDICAL INSTRUMENTATION II LECTURER: ALİ IŞIN LECTURE NOTE 2 BLOOD PUMPS BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Blood Pumps • Mechanical devices used to assist the heart in circulating the blood. • Aids the failing heart after a surgery • Reduces the load driven by heart • Some advanced pumps can completely replace the heart (Artificial Heart). BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Intra Aortic-Balloon Pump BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Intra Aortic-Balloon Pump. • Used to increase myocardial oxygen delivery by increasing coronary blood flow. • Consists of a long cylindrical polyethelene balloon that can be introduced into the aorta through a femolar (thigh related) artery and connected to an external drive apparatus. • It actively deflates in systole, increasing forward blood flow by reducing the load. It actively inflates in diastole, increasing blood flow to the coronary arteries. BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Intra Aortic-Balloon Pump. . • Pressurized CO 2 is applied to the balloon for inflating. • CO 2 is used because it is more soluble in blood than air. Thus, there is less risk of fatal gas embolism (obstruction of the circulatory system caused by an air bubble) if the balloon or its supply tubing leaks or rupture. BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Intra Aortic-Balloon Pump… • The device rely on electronic controls to detect ventricular contraction either from a pressure sensor at the arch of the aorta or from the ECG. • The signal then go through appropriate delay circuits to control the suction and pressurized CO 2 supplied to the balloon. • Appropriate sensors are included in the system to ensure that alarms are sounded if any leaks occur. BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Ventricular Assist Device (VAD) • A ventricular assist device (VAD) is a mechanical pump used for temporary blood circulation support. It decreases the workload of the heart while maintaining adequate flow and blood pressure. BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Purpose • A VAD is a temporary life-sustaining device. VADs can replace the left ventricle (LVAD), the right ventricle (RVAD), or both ventricles (BIVAD). They are used when the heart muscle is damaged and needs to rest in order to heal or when blood flow from the heart is inadequate. VADs can also be used as a bridge in patients awaiting heart transplantation or in patients who have rejected a transplanted heart. BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Example of one VAD device: Heart. Mate ® Implantable BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Ascending Aorta Apex Titanium Pump BME 312 -BMI II-L 2 -ALİ IŞIN 2015
The VAD consists of: • A pump unit, implanted in the abdomen (location of placement is based on the patient's past medical history, anatomy and surgeon preference) • An inflow tube (or conduit), attached to the bottom of the left ventricle (apex) • An outflow tube, attached to the aorta (the large artery that carries blood away from your heart) • Internal valves that allow for one-way blood flow through the system • Power leads, that pass from the internal device through the skin, and outside your body. The outside of the tube is covered with a special material so that skin cells grow into the material and aids healing. BME 312 -BMI II-L 2 -ALİ IŞIN 2015
The VAD consists of: • External controller and power base unit or battery pack that attaches to the power leads/cables. The controller is programmed to maintain a specific pump spread. It displays the status of the system and any alarm messages, and also sounds alarms if needed. The batteries are rechargeable and changed daily. • The controller and batteries can be worn in a belted waist pack or a holster under the arm. Or, it may be connected to a power base unit and plugged into a wall outlet. • The type of pump and other components depends on the type of VAD used BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Mobility and freedom • The VAD allows patients to be mobile, and return home. A detailed education program is provided to the patient and family, or patient support system, to ensure safety and proper use of each of the components. The patient must demonstrate independence with self care, and management of the device and potential emergency situations before leaving the hospital BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Patients who might be candidates for a VAD • Examples: • have suffered a massive heart attack • cannot be weaned from heart-lung bypass after treatment with intravenous fluids, medications, and insertion of a balloon pump in the aorta • have an infection in the heart wall that does not respond to conventional treatment • are awaiting a heart transplant and are unresponsive to drug therapy and intravenous fluids • are undergoing high-risk procedures to clear the blockages in a coronary artery BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Types of VADs • There are four types of VADs, each appropriate for a different condition. Surgery to install a VAD is performed under general anesthesia in a hospital operating room. An incision is made in the chest, then catheters are inserted into the heart and the correct artery. The surgeon sutures the catheters in place, then attaches tubing to connect the catheters to the pump. The pump stays outside the body. Once it is turned on, blood flows out of the diseased ventricle and into the pump, then is returned to the correct blood vessel leaving the heart. BME 312 -BMI II-L 2 -ALİ IŞIN 2015
After insertion • The patient is monitored in intensive care, with follow-up blood, urine, and neurological studies. Blood thinning medications are given to prevent blood clotting. • Except for those patients awaiting a heart transplant, patients are slowly and gradually weaned from the VAD. Even when patients no longer need the VAD, they will require supportive drug therapy and/or a balloon pump inserted in the aorta. BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Risks • Bleeding from surgery is common and occurs in as many as 30 -50% of patients. Other complications include the development of blood clots, partial paralysis of the diaphragm, respiratory failure, kidney failure, failure of the VAD, damage to the coronary blood vessels, stroke, and infection. • Sometimes when the left ventricle is supported, the right ventricle begins to need assistance. If VADs are inserted in both ventricles, the heart may become so dependent on their support that they cannot be removed. BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Roller Pump BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Roller Pump – Eccentric Shaft BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Multiple Finger Pumps BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Pumps • Roller pumps and Multiple-finger pumps are employed because the pump itself does not come in contact with the blood. • Disposable, flexible tubing are used to contain blood that is pinched between the propagating rollers or fingers. BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Reciprocating Pump BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Pulsatile Pumps • Pulsatile pumps - consisting of a chamber subjected to the reciprocating motion of a piston, membrane, or bladder - are also used with appropriate check valve to direct the flow. • Such pumps more closely follow the normal action of the heart and produce a pulsatile blood pressure. BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Pump Oxygenators • Can carry out both blood pumping and blood oxygenation. • Consists of • Pumps for maintaining arterial blood pressure • Oxygenators connected in series with the pump that increase blood O 2 content and remove CO 2. BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Pump Oxigenators BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Oxygenators • Used for patients who have severe lung diseases. • Two types of Oxygenators: • Film type • A large-surface-area film of blood is drawn into contact with a nearly 100% O 2 atmosphere by rotating disks. • Membrane Oxygenator • Blood flows through fine tubes of a membrane permeable to gas • Has a large exchange surface area to allow the gas transfer to take. BMEplace. 312 -BMI II-L 2 -ALİ IŞIN 2015
Total Artificial Heart BME 312 -BMI II-L 2 -ALİ IŞIN 2015
Total Artificial Heart • Blood pumps have been miniaturized and constructed of such materials that they can replace the natural hearts of patients • Implanted in the thoracic cavity and operate via pneumatic and electric connections to an external drive apparatus. BME 312 -BMI II-L 2 -ALİ IŞIN 2015
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