Sunday, 21 June 2020

Dopller of middle cerbral artrry


Mother : Definition & Qualification of a mother??  Ans: In the vast world it is the own mother who first realizes that her son/daughter is unwell, irrespective of their age . Mother understands this even her son/ daughter is thousand Km away from her by listening to voice /video call.  Even if her sibling is at UK/US and I have no hesitation that irrespective of sibling’s age. The voice of her son/ daughter sends signals which can be picked up by mother earliest. I repeat earliest. This is untrue in case of MCA Doppler but possibly true in case Umb A Doppler.

 Q.1:-How best we can utilize “Middle  Cerebral  Artery”..Ans:-MCA offers us some signals which we the Obstretricins must be ready to interpretof  such warning ringing bail---something is  wrong in foetus.
Doppler   Velocimetry   interrogation    of the middle   cerebral artery   has received   particular   attention because   of observation that the hypoxic fetus attempts brain  sparing by reducing cerebrovascular impedance , cerebral A  dilatation , more blood flow to cerebrum due to systemic  anoxia and thus   increasing blood   flow to such a vital organ  like brain.
Such brain sparing in growth restricted fetuses   has been reflected by  USG to undergo reversal of PSV in MCA in the sense of more diast flow in MCA as anoxaemia progresses due to placental insuffinecy  . Many a investigators have reported   that about 50% of such  fetuses with  this kind of reversal died if such an important finding is  ignored .
Q.2:-:-Which one is a better method to pick up foetal anoxaemia? Modified BPP or MCA Doppler???  Ans:- With graet curiosity , the researchers have curiously randomized     women undergoing   a) modified   biophysical profile   evaluation    b)  MCA Doppler  or c)  combined   with   middle cerebral  and umbilical   artery  velocity flow   assessment   . There were no significant  differences in pregnancy outcomes  between  all these three    study groups.
 Q. 3:-What is Peak Systolic Velocity (PSV) ? Ans:-It is  the threshold values  >1.5   multiples   of the median  for given  gestational   ages correctly identified   all fetuses with moderate   or severe   anemia.  This provided a sensitivity of  100 percent with  a false positive   rate of  12 percent.
Q. 4:Cut off punt? Warning bell –at what point of time? What PSV findings will tell  is by carrying out for more frequent MCA Doppler follow up??  Ans:-The MCA   peak systolic velocity is to be followed serially and values are plotted on a curve. If the velocity is between 1.0   and 1.5  MoM   and the slope is  increasing -  such that the value  is approaching  1.5 MoM – surveillance is generally  increased to weekly  Doppler interrogation.
Q. 5:-Comparing serial “amniocentesis for measurement of bilirubin levels”    with “Serial  Doppler   measurement in MCA ?? Ans:-Researchers have  in last three decades confidently  used middle   cerebral  artery Doppler    Velocimetry in eiu of Liley curve of quantifying bilirubin in A fluid  to detect severe  fetal anemia  in    fetuses   with D alloimmunization ??
Ans:-. They   prospectively compared serial amniocentesis for measurement of bilirubin levels   with Doppler   measurement of peak  systolic velocity  in the middle   cerebral artery. These   investigator concluded that Doppler   could safely replace   amniocentesis in the management of allo immunized  pregnancies. Remind you my dear members that middle cerebral artery Doppler Velocimetry is useful for detection and management   of fetal anemia of any etiology  . The American College  of   Obstetricians  and Gynecologists   also concluded   that  such use of Doppler is appropriate  in centers  with personnel   trained in the procedure.

Q.6: When to proceed for Cordocentesis to estimate foetal anemia directly??  Ans:-If the MCA   peak systolic velocity    exceeds 1.5 MoM , and if one intends to continue the indexed pregancy then only further    evaluation by  fetal blood sampling is necessary . This complex invasive procedure is carried out to assess   need for fetal   transfusion. The false positive rate  increases   significantly   beyond 35   weeks due to the   normal increase   in cardiac   output that develops  at this gestational age Q.7:-At prsent time is there any indication of Cordocentesis to diagnose foetal  anemia with certainty  in cases of Rh iso immunization?? How best to diagnose Foeatal anemia, indirectly ?? Is it study of MCA??  Ans:-In most specialist centers , serial  measurement  of the peak  systolic velocity  of the fetal middle cerebral   artery has   replaced   amniocentesis   for the detection of fetal   anemia. The anemic fetus shunts blood   preferentially   to the brain to maintain adequate   oxygenation. The velocity increase because of increased cardiac output    and decreased blood viscosity (foetal anemia ) . But the   technique, as in other fields  of Obstet imaging  should be used only with adequate   training  and experience   .

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