Patients on extracorporeal membrane oxygenation (ECMO) received relatively low doses of sedatives and analgesics while at a light level of sedation in a single-center prospective study of 32 patients.

In addition, patients rarely required neuromuscular blockade, investigatorsreported online in the Journal of Critical Care.

This finding contrasts with current guidelines on the management of pain, agitation, and delirium in patients on ECMO. The guidelines are based upon previous research that indicated the need for significant increases in sedative and analgesic doses, as well as the need for neuromuscular blockade, wrote Jeremy R. DeGrado, PharmD, of the department of pharmacy at Brigham and Women’s Hospital, Boston, and his colleagues (J Crit Care. 2016 Aug 10;37:1-6. doi: 10.1016/j.jcrc.2016.07.020).

“Patients required significantly lower doses of opioids and sedatives than previously reported in the literature and did not demonstrate a need for increasing doses throughout the study period,” the investigators said. “Continuous infusions of opioids were utilized on most ECMO days, but continuous infusions of benzodiazepines were used on less than half of all ECMO days.”

Their 2-year, prospective, observational study assessed 32 adult intensive care unit patients on ECMO support for more than 48 hours. A total of 15 patients received VA (venoarterial) ECMO and 17 received VV (venovenous) ECMO. Patients received a median daily dose of benzodiazepines (midazolam equivalents) of 24 mg and a median daily dose of opioids (fentanyl equivalents) of 3,875 mcg.

The primary indication for VA ECMO was cardiogenic shock, while VV ECMO was mainly used as a bridge to lung transplant or in patients with severe acute respiratory distress syndrome. The researchers evaluated a total of 475 ECMO days: 110 VA ECMO and 365 VV ECMO.

On average, patients were sedated to Richmond Agitation Sedation Scale scores between 0 and −1. Across all 475 ECMO days, patients were treated with continuous infusions of opioids (on 85% of ECMO days), benzodiazepines (42%), propofol (20%), dexmedetomidine (7%), and neuromuscular blocking agents (13%).

In total, patients who received VV ECMO had a higher median dose of opioids and trended toward a lower dose of benzodiazepines than those who received VA ECMO, Dr. DeGrado and his associates reported.

In total, patients in the VA arm, compared with those in the VV arm, more frequently received a continuous infusion opioid (96% vs. 82% of days) and a benzodiazepine (58% vs. 37% of days). These differences were statistically significant.

Adjunctive therapies, including antipsychotics and clonidine, were administered frequently, according to the report.

“We did not observe an increase in dose requirement over time during ECMO support, possibly due to a multi-modal pharmacologic approach. Overall, patients were not deeply sedated and rarely required neuromuscular blockade. The hypothesis that patients on ECMO require high doses of sedatives and analgesics should be further investigated,” the researchers concluded.

The authors reported that they had no disclosures.