In the USA, there are two types, not one. You have the 45X that you are familiar with, and then you have the 36.83X (the bicarbonate consists of NaHCO3 + Na and is paired with an acid bath that has a lower sodium content than the 45X) that is also used, but it is slowly fading out due a major inability to easily sodium profile when compared to the 45X. 35X can also be done in the US, but is more commonly used Internationally. India have their own unique baths, and I do mean unique. And I do think there was a 33X at one time. Lastly, the use of Acetate for dialysis (treatment without a bicarbonate buffer) has largely been eliminated because hemodialysis machines can now properly control three stream processing of the dialysate mixture (water, acid, and bicarbonate).
"The nine most terrifying words in the English language are: I'm from the Government, and I'm here to help." - Ronald Reagan