LAS VEGAS—Managing profound hypotension in the critically ill can be complex. Peter M. DeBlieux, MD, FACEP, urged attendees to apply situational awareness—avoiding a “fixed recipe” dogmatic approach to these patients.
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Dr. DeBlieux, a Louisiana State University Health Science Center, professor of emergency medicine and professor of pulmonary and critical care medicine in New Orleans, shared his experiences on common treatment plans for cardiogenic, obstructive, septic, and spinal shock. He also noted the surprisingly limited science supporting the complex treatment and management of these patients.
For the patient in cardiogenic shock presenting with primary pump failure, limited cardiac output, reduced coronary perfusion pressure with reduced mean arterial blood pressure (MABP), and increased heart rate corresponding to raised myocardial oxygen demand, the first line of defense is dobutamine, said Dr. DeBlieux.
According to current advanced cardiovascular life support (ACLS) practice, a patient with a systolic blood pressure (SBP) of less than 90 mm Hg should receive dobutamine. If the SBP is less than 80 mm Hg, dopamine is the best choice. Anything less than 70 mm Hg requires levophed. However, Dr. DeBlieux is dismissive of this last recommendation. “It’s based on next to zero evidence,” he said.
A 2006 study recommends using dobutamine with or without norephinephrine for first line therapy and dopamine and epinephrine as second and third line agents.
He warned that, in these cases, phenylephrine is “not your friend;” stating that it offers pure alpha stimulation that can cause an increased afterload without improving contractibility resulting in reflex bradycardia.
He suggested assessing volume status in order to identify the benefit of fluid boluses. Also, consider the patient’s heart rate. If the patient is tachycardic, choose an agent with reduced beta. Finally, keep a drip at a minimum to maintain a blood pressure of 75 mm Hg or more. “Our goal of 65 is not the goal for acute coronary events,” he said.
In the case of pulmonary embolus or shock with acute pulmonary hypertension, Dr. DeBlieux said the best vaso-active agent is norepinephrine. Although there is no human data, limited animal studies support that norephinephrine is associated with improved survival, improved cardiac output and coronary blood flow, and minimal changes in pulmonary vasculature. “Be cautious with fluid application,” he said.
Norepinephrine is also the agent of choice for patients in septic shock, Dr. DeBlieux said—although dobutamine and epinephrine can also be helpful. “Vital signs are not the marker here. Lactate is more important,” he said. Serial lactate measurements should guide ongoing resuscitation efforts.