An anesthesia resident was givnig spinal anesthesia when the patient had sudden aphonia and loss of consciousness. What could have happened?

C i.e. Vaso vagal attack Total spinal anesthesia - Ocurs if the large volume of LA used for epidural -anesthesia is injected into subarachnoid space i.e. it occurs following epidural/caudal anesthesia, if there is inadveent intrathecal injection of large volume of drugs. - It occurs after (not during injection) Vasovagal attack or emotional fainting (Syncope) Likely to occur paicularly in an anxious patient with a rapidly ascending spinal block. It may occur instantaneously even during the procedure (e.g. spinal)Q. Pallor, nausea and (neurocardiogenic) bradycardia or asystole are a/w hypotension and fainting. Rapid resolution results from placing the patient in head down position and administration of iv ephedrine or atropine. Systemic toxicity - If large amount of LA reach the tissues of hea and brain they exe the same membrane stabilizing effect as on nerve resulting in progressive depression of function. The earliest feature is numbness or tingling of tongue and circumoral area; b/o rich blood supply to these tissue depositing enough drug to have an effect on nerve endings. The patient may beome light headed, anxious, drowsy and or complain of tinnitus. Convulsions, loss of consciousness, coma and apnoea may develop subsequently. Cardiovascular collapse may result from direct myocardial depression and vasodilation or hypoxemia d/t apnoea. - The most ommon cause is accidental intravascular injectionQ but it may also result from absolute overdose during blocks. System absorption of LA is greatest after intercostal nerve block and caudal anesthesia; intermediate after epidural anesthesia > brachial plexus > sciatic & femoral nerve block; and least after infiltration anesthesia.