THE HEART-LUNG MACHINE

An excerpt from Os Doran’s first thriller, Nudge Nudge Wink Wink Die

Copyright © 2017 Riis Marshall and Turfhill Court Press


The senior surgeon spoke to Bill without turning from his work: ‘Let’s go on bypass.’

Bill unclamped the venous line and adjusted the flow, then: ‘We’re on bypass.’

Venous blood returning to the heart from the body through two major veins, the superior and inferior venae cavae now flowed into cannulae inserted in these veins then into flexible plastic tubing leading to a reservoir mounted on Bill’s pump console. From the reservoir it flowed into an oxygenator where, as in the lungs, adding oxygen and removing carbon dioxide turned it from venous into arterial blood. A roller pump returned it to the patient through more plastic tubing; here it re-entered the patient’s body through another cannula inserted in the femoral artery. It coursed ‘backwards’ up the descending aorta and the aortic arch as far as the aortic valve. During its ascent it streamed from this major artery into the entire arterial system, delivering oxygen to the body.

The heart-lung machine—an amazing creation of the human mind. Pundits refer to it simply as ‘the pump’. It replaces a patient’s heart and lungs during operations so surgeons can make repairs to the heart or surrounding major blood vessels. On bypass these major organs are isolated completely from the patient’s cardiovascular system while the pump maintains full blood flow to the entire body, but especially to the brain that cannot survive without irreparable damage if deprived of oxygen for more than about three minutes.

Apart from more effective oxygenation technology and some electronic gadgetry, this machine has changed very little since it began to see service in operating theatres in the late fifties and early sixties in the last century. And the one element unchanged over these sixty years is the perfusionist, sometimes referred to as the ‘pump technician’, sometimes as the ‘heart-lung machine operator’ and sometimes most grandly as an ‘extracorporeal circulation technician’. Although surrounded very closely by a dozen of the most thoroughly competent individuals regularly gathered in one room and totally committed to their joint work, his job is one of the loneliest in the world.

Bill changed into scrubs at six forty-five in the morning on a typical workday and trundled the console and perfusion system into the operating theatre. There is nothing really impressive or even vaguely interesting about the console other than to the uninitiated—a stainless steel box on wheels comprising roller pumps, a few switches, dials and gauges.

He positioned the console out of the way of people going about their various duties. Then he set the perfusion system—clearly more impressive than the console—on top of it. The perfusion system is a thoroughly complicated assembly of mostly transparent plastic components in various sizes and shapes, some enclosing bits of arcana relevant to their functions. Flexible, clear plastic tubing, part of it concealed within sterile wrappers, joins all these components.

Bill primed his machine with one and one-half litres of an isotonic fluid: Hartmann’s solution, sometimes called ‘CSL’. He removed a unit of CSL from a supply cabinet and recorded the batch number in his notebook. Before he emptied this unit into the reservoir, he held up both the unit and the entry in his notebook for inspection by the circulating nurse. After she confirmed the information he recorded agreed with the information on the label, he transferred the solution to the machine. The nurse repeated this confirmation for all three units. By now surgeons had entered the theatre, were gowned and gloved, arranged themselves at the table and began the operation.

He moved the pump to directly behind the senior surgeon then arranged a stool, sat down comfortably, turned on the oxygen and one of the pumps circulating fluid through the machine then noted the level in the reservoir.

Now his workday truly began. He quietly said to the senior surgeon: ‘We’re ready to go on bypass,’ then sat back and waited until they were ready.

Later the surgeon turned to him: ‘We’re ready for the lines.’

Bill reached for the one part of this system still enshrouded in a sterile wrapper, opened it and carefully exposed a coil of plastic tubing with fluid coursing through it. The surgeon manoeuvred it up and onto the table with no danger to the integrity of the sterile field. Bill placed a clamp on the venous line and sat back again. He said nothing; he was asked no questions.

It was a simple as this: from the time the surgeon ordered him to go on bypass until the patient came off, anywhere from ten minutes to eight hours according to the severity of the defect and the nature of the repair, he sat silently attending his machine. He and his machine were a unit with one aim: to maintain the patient’s blood pressure and volume. And in spite of the apparent complexity of this mass of gleaming stainless steel, pumps, plastic gadgets and tubing, he achieved this doing nothing more than maintaining the fluid level in the reservoir by making minor adjustments to the speed of the roller pumps. He might have opted for an electronic monitoring system to do this automatically but preferred to do it manually, arguing this kept him alert.

Later the surgeon spoke, again without looking away from the field: ‘Let’s come off bypass.’

Bill clamped the venous line: ‘We’re off bypass.’

When they were satisfied the heart was functioning normally, they removed the lines and handed them back to him. He wheeled the pump into the corridor, took a break then began the rest of his work for the day.

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