Milrinome is superior to epinephrine as treatment of myocardial depression due to ropivacaine in pigs

Purpose: To determine whether milrinone is more effective than epinephrine in the resuscitation of ropivacaine induced cardiotoxicity in pigs. Methods: Arterial, pulmonary, and LVdP/dt catheters were placed in 12 anesthetized, intubated and mechanically ventilated pigs. They received ropivacaine iv to cardiovascular toxicity: 50% decrease in LVdP/dt, cardiac output and mean arterial pressure (MAP). Group 1 (n=6) was treated with 100 μg·kg^-1 milrinone iv, and Group II (n=6) received 0.5 mg epinephrine iv. Resuscitation was successful if cardiac output returned to baseline, and MAP reached 80% of baseline. Results: After ropivacaine, MAP decreased from 88 ± 7 to 49 ± 8 mmHg (P < 0.05), CO decreased from 2.8 ± 0.4 to 1.2 ± 0.2 L·min^-1 (P < .05), HR decreased from 103 ± 8 to 74 ± 7 beats·min (P < 0.05) and LVdp/dt decreased from 1950 ± 130 to 755 ± 125 mmHg (P < 0.05). The LV EDP increased from 5 ± 1 to 8 ± 1 mmHg (P < 0.05) and SVR from 2317 to 3000 ± 120 developed arrhythmias. In contrast, epinephrine produced severe hypertension and tachycardia. There was no improvement in CO or SV, and SVR increased. Epinephrine caused A-V dissociation and ventricular arrhythmias in three animals. [[Conclusion: Milrinone, was more successful than epinephrine in resuscitating anesthetized pigs from ropivacaine-induced cardiovascular toxicity.