<prompt> All are true about thiopentone exceptNa2CO3 is a preservativecontraindicated in porphyriaAgent of choice in shockHas cerebroprotective action  <response>: In situations where the baroreceptor response will be blunted or absent eg, hypovolemia, congestive hea failure, b-adrenergic blockade, cardiac output and aerial blood pressure may fall dramatically due to uncompensated peripheral pooling of blood and direct myocardial depression. So, sodium thiopental is contraindicated in shock. Ref: Morgan Mikhails clinical anesthesiology 6e 