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Living Without a Pulse
SteamyMobile writes "Can you live without a pulse? Yes, now you can. The reason why we have a pulse is because it's hard for evolution to result in turbines or continuously spinning things. The next generation of artificial hearts may have no pulse. They also have no bearings, so they should last much longer than previous attempts. In fact, engineers don't give a predicted lifespan on these models. How would your life be different without a pulse?"
While ths scenario is pretty funny...most CPR certified professionals check for breathing, not a pulse. And if they didn't, then they shouldn't be certified. Yes, they also check for a pulse, but not before they check for breathing. Depending on the body fat on a person, the pulse isn't always easily detected.
"Time is long and life is short, so begin to live while you still can." -EV
Actually, current pacemakers can only be set to one speed, so people who have these devices already have the limitation of non-variable heartrate. While this is a setback for the pacemaker-using crowd, almost all agree that having a non-variable heart rate is better than having no heart rate at all.
Only arteries have a pulse. The blood flow is as follows: heart -> arteries -> capillaries -> veins -> heart. By the time the blood gets thru the capillaries to the veins the blood pressure is vastly reduced and the pulsatile flow generated by the heart is not felt in the veins. Hence veins do not have a pulse. The valves in the veins have nothing to do with the pulsatile flow of the heart and hence a constant flow heart will not affect the functioning of the veins in any way. Venous problems like varicose veins, cirrose like vena portalis deformities are not related to how the heart pumps.
I'll bite: I'm not golfing because I don't have the patience. IAAS (I am a Surgeon) and it would not be that difficult to measure a continuous flow generated pressure instead of a pulsed pressure. Plus you wouldn't have to teach us about turbines and such. For example, currently a patient in the ICU may have their blood pressure measured with an indwelling arterial line rather than a transduced cuff. We follow Mean Arterial Pressure (MAP) in this setting. Here's a quick definition: http://www.globalrph.com/map.htm (It was easier to google than find a textbook but this is short and sweet)- "Equation: MAP = [(2 x diastolic)+systolic] / 3 Diastole counts twice as much as systole because 2/3 of the cardiac cycle is spent in diastole. An MAP of about 60 is necessary to perfuse coronary arteries, brain, kidneys. Usual range: 70-110." We could still measure the equivalent of a MAP with a continuous pump. Some of the bioengineers who commented above probably know better, but whatever the range of pressure in the system from continuous pumping (whether it's always the same or if there's a smaller variation than the normal systolic/diastolic) it could still be accounted for and easily monitored and used to guide therapy. Probably the bigger problems are those already mentioned: baroreceptors that will now be in a new range, changes in coagulation, and destruction of blood borne cellular elements.