Inadvertent intrathecal injection of large dose magnesium sulfate
The case was a 35-year-old man whom presented with a strangulated inguinal hernia. He had been brought to the operating room at 3 AM in an emergent situation when the operating room personnel were tired and sleepy because of a previous busy night. Anesthesiologist chose spinal anesthesia in a sitting position with 3 ml of bupivacaine (0.5%). Immediately after drug injection, the patient laid himself down on a supine position. The anesthesiologist tilted his body about 10-15 degrees to a head-down position to reach a sensory block level up to T4-6. About five minutes later, the patient suffered respiratory distress, bradycardia, hypotension and loss of consciousness. He was intubated and simultaneously 1 mg intravenous atropine was injected. In spite of atropine injection, hypotension and bradycardia continued, which resulted in rapid infusion of normal saline and bolus injection of 100 μg epinephrine. Subsequently, IV epinephrine infusion (20-30 μg/min) was established because of unstable cardiovascular status. Searching for the source of problem revealed that 3 ml of magnesium sulfate 50% (1.5 g) was injected mistakenly instead of bupivacaine.\nThis mistake occurred because of two reasons: First, the similarity of the shape of drug containers and its labels [] and second, the anesthesiologist was sleepy and careless.\nAfter about one hour, his hemodynamic status became more stable while epinephrine drip at a lower infusion rate was continuing. However, he was totally paralyzed and unconscious; hence, the surgeon performed the herniorrhaphy, and epinephrine drip gradually was tapered and stopped up to the end of operation. At the end of the surgery, in spite of stable hemodynamic status, because of continuing unconsciousness and muscle paralysis, the intubated patient was transferred to intensive care unit (ICU). Hemodynamic monitoring and respiratory support at the ICU went on and morphine–midazolam infusion (1-2 mg/h) was established for preparing an acceptable sedation. After 24 h, he became fully conscious but because of residual muscle paresis, the patient couldn’t be weaned from mechanical ventilation. Thus, he remained intubated and sedative drug infusion was continued up the next morning.\nIn the third day, the muscle power became better and finally the patient was successfully extubated. Thereafter, a lower limb physiotherapy was performed for about two days and he was able to walk on day 4. After taking an MRI of spinal cord which was normal, the patient was discharged on the fifth day. Three weeks later, an electromyography and a nerve conducting velocity study were performed that showed a normal result. The patient followed up for 6 months and fortunately he didn’t show any obvious complication during that period. Permission for publication was obtained from the patient.