Heart-Lung Machine – A Key Device in Cardiac Surgeries

A heart-lung machine is a medical apparatus which renders cardiopulmonary bypass (CPB), or mechanical circulatory support of the lungs and heart. It is a medical device used in an open heart surgery to hold up the body at the time surgical procedure when the heart is stopped. It temporarily does the function of the lungs and heart and thereby maintaining the blood circulation and the oxygen content of the patient’s body.  A more technical term of the heart-lung machine is cardiopulmonary bypass (CPB) pump or ‘the pump’. The machine comprises of arterial cannula (tubes) and venous, reservoir (to hold blood), polyvinyl chloride (PVC) or silicone tubing, cardiotomy (filtered reservoir), bubbler or membrane oxygenator, arterial line filter pumps, heat exchanger(s), inline blood gas and electrolyte analyzer, flow meter and pressure-monitoring devices. The heart-lung machine has a chamber which receives blood from the body (something that a heart’s right atrium does) and the machine then pumps the blood with an oxygenator, which right ventricle of the heart does. This procedure eliminates the carbon dioxide from the blood and adds oxygen. It also maintains the temperature of the blood and pumps the blood back to the body. The heart-lung machine is connected by sequential tubes which the surgical team places on the patient. Lastly, when the surgical procedure is over, the surgeon in a very gradual manner lets the patient’s heart to recommence its normal function, and the hear-lung machine is weaned-off.

The Heart Lung Machine market study states a fact that the first ever successful open heart surgery by using a heart-lung machine was carried out on 6^th of May, 1953. The machine is used for two primary reasons – (1) Heart can be stopped for a surgery, (2) Help an individual with heart failure.

Several surgical conditions wherein heart-lung machine is put to use:

·         Cardiac valve replacement or repair

·         Coronary artery bypass surgery

·         Transplantation

·         Repair of congenital heart defects

·         Repair of large aneurysms

·         Ventricular septal defects

·         Pulmonary thromboendarterectomy (PTE)

·         Pulmonary thrombectomy

Lastly, a heart-lung machine consists of a pump, cannulae, reservoir, temperature control, and oxygenator, filter, roller/centripetal pump, and connected by a series of PVC or silicone tubes.