Pulseless electrical activity is the presence of electrical complexes without accompanying mechanical contraction of the heart. Potential mechanical causes should be diagnosed and treated, including severe hypovolemia, cardiac tamponade, tension pneumothorax, massive pulmonary embolus, MI, and toxic ingestions (eg, tricyclic antidepressants, calcium channel blockers, β-blockers). In addition, profound metabolic abnormalities such as acidosis, hypoxia, hypokalemia, hyperkalemia, and hypothermia also should be considered and treated.
After intubation and initiating CPR, administer epinephrine, 1 milligram IV/IO (1:10 000 solution) every 3 to 5 min. If giving via endotracheal tube, increase the dose 2 to 2.5 times and follow with several rapid ventilations to disperse the drug. Treatment is guided by rapid identification and treatment of the underlying cause. Use agents with α-adrenergic activity, such as norepinephrine and phenylephrine, to improve vascular tone when indicated. Electrical pacing is not effective.