Vasopressor of choice in hypotension produced during sub-arachnoidblock
A i.e. Ephedrine Most common complication of spinal anesthesia is hypotensionQ, which can be prevented by preloading with crystalloid. In spinal anesthesia autonomic preganglionic sympathetic fibresQ are the earliest blocked fibres. Block of sympathetic nerves causes vasodialation of venous capacitance vessels, pooling of blood and HypotensionQ (most common complication of spinal anesthesiaQ). It is prevented by preloading with crystalloid. Following spinal subarachnoid block most common complication is hypotensionQ. During sub-arachnoid block, there is sympathetic blockade producing decreased venous return & hence, cardiac output and BP falls. So the patient can be managed by all the four means but the least effective & most controversial mean is lowering head end. The specific gravity (baricity) of CSF is 1.003 - 1.008Q at 37degC. A hyper baric solution of LA is denser than CSF & hypobaric solution of LA is Lighter than CSF. A LA solution can be made hyperbaric by adding glucose & hypobaric by addition of sterile water. Most impoant factors affecting level of spinal anesthesia are: BaricityQ, Position of patient - during & immediately after injection,Q drug dose & site of injection. Thus with a head down position a hyperbaric solution spreads cephald & hypobaric solution moves caudad and vice versa. And in this Q baricity of LA & time passed after injecting spinal anesthesia is not mentioned, so lowering the head end is weakest option.
Ephedrine
Mephenteramine
Adrenaline
Dopamine