reaction with bone cement ??????!!!!!!!!

[kalpesh shah]

hi, i have observed mild to moderate change in pulse and B.P. immediately after cementing in major orthopedic surgery specially femur. almost 20 % of pt showes such responce !!!!
  what is your experience ?????

[Dr. Mian]

Bone cement is made up of polymethyl methacrylate.  Different theories exist as to why there can be hypotension with cementing.  These include microemboli and reaction to the chemical in the cement.  I think it is also important to note that the process of cementing is also temporally related to the process of reaming (pounding the intramedullary cavity) which I have found to often trigger vagal response.

[kalpesh shah]

thanks for responce.
my observation is tachy and hypotension...., with out any other signs of anaphylactiod reaction.!!!!
is there any evidance of microembolisum related hypotension after cementing????
any prophylactic staps to prevent this ????


want's to have comments from more members .....


thank you.

[jafo1964]

Apart form  microemboli, methyl acrylate releases vasoactive mediators of inflammation which produce vasodilatation and decrease in SVR. So BP  falls leading to hypotension. The blood volume gets held up in the peripheries, so Preload drops, and heart tries to compensate the CO decreases by increasing heart rate, hence tachycardia. Although these vasoactive amines by themselves can produce tachycardia.

Till a few years ago, 200 mg of Hydrocortisone was being given prior to placement of cement claiming that it decreased the inflammatory material release. Recent evidence proves that this practice is unscientific and hence has been dropped, although quite a few anaesthetists still continue this practice.
I have have totally stopped with steroids.


what is recommended now

Before placing cement give adequate fluids and make sure hypotension is corrected and preload is optimal.
Doses of vasopressors like phenylephrine and ephedrine may be used to prevent hypotension.
True anaphlaxis is rare but possible, must be recognized and treated appropriately
Also remember the cement is placed immediately after reaming of bone hence blood loss and hypotension may already be present and this may further compound the problem

regs

[Pingwin]

I agree with jafo1964. We treat bone cement reaction with fluids (given prior to cementing), ephedrinum and - of course - oxygen.