Author: Thomas Rosenthal
Using neuromuscular blocking agents (NMBAs) does not allow surgeons to close the abdomen of trauma patients after damage control laparotomy (DCL) any faster than for those who are not given NMBAs, a study has concluded.
Abdominal closure was achieved in a median of two days for both the 125 patients who received continuous NMBAs in the first 24 hours after DCL and for the 97 patients who did not receive the agents, according to a retrospective cohort study at an adult trauma center.
In addition, using NMBAs increased the use of sedative agents, which were associated with a higher risk for delirium, according to research presented at the 2018 annual meeting of the Society of Critical Care Medicine (abstract 1582).
Dr. Smith added, “We would recommend initially attempting to sedate trauma patients with open abdomens without the aid of NMBAs.” NMBAs increased sedation requirements; propofol and fentanyl were the primary sedatives used.
If clinicians are unable to keep the patient adequately sedated and they are visibly uncomfortable, for example, pushing abdominal contents out against a vacuum-assisted closure dressing or becoming agitated, then NMBAs may be a useful adjunctive strategy—but only for some patients, Dr. Smith said.
The study was performed between 2009 and 2015. The NMBA group received higher cumulative doses of propofol (54mg; interquartile range [IQR], 16-106) compared with the non-NMBA group (20mg; IQR, 0-69; P<0.0001) for the first seven days after undergoing DCL. The two groups received comparable fentanyl dosages (NMBA+ group, 11mg; IQR, 7-16 vs. NMBA– group, 9mg; IQR, 5-16; P=0.085). “Richmond Agitation Sedation Scale (RAss) scores were significantly lower in the NMBA+ group on the first 5 days following DCL, despite a median duration of NMBA of 26 hours,” the authors noted.
“While there was no direct association between NMBA use and delirium/coma, the association between sedation and delirium/coma-free days confirms a known adverse effect of propofol and highlights the importance of considering the effect of sedation on delirium and awakening following damage control laparotomy,” Dr. Smith said.
“This study provides valuable insight into the effects of neuromuscular blockade on sedation requirements and delirium in patients undergoing damage control laparotomy,” said Matthew E. Lissauer, MD, a critical care surgeon at Rutgers Robert Wood Johnson Medical School, in New Brunswick, N.J., who was not associated with the study.
Dr. Lissauer said the researchers demonstrated that NMBAs affect sedation beyond the duration of paralysis. “While median duration of neuromuscular blockade use was only 26 hours, there was a significantly higher percentage of patients with RAss scores in the –4 to –5 range (deeply sedated) out to five days. This effect was primarily due to an increased usage of propofol in the chemically paralyzed group,” he said.
Dr. Lissauer added: “While neuromuscular blockade has been found to be efficacious in disease processes such as ARDS [acute respiratory distress syndrome], the same cannot necessarily be said for management of the open abdomen to improve closure metrics. Neuromuscular blockade did not change time to closure, which is often the primary reason for its use in this population. Based on these results, consideration should to be given to the adverse effects of the extra sedation use associated with neuromuscular blockade in this patient population, and clinicians absolutely need to be cognizant of its risks and benefits.”
Dr. Smith said, “For patients not on NMBAs, we tend to rely more on clinical assessments to determine adequacy of sedation. For our patients on NMBAs, we are unable to assess them clinically. Therefore, we intentionally targeted higher sedation goals to limit patient agitation and distress with being paralyzed and inadequately sedated. This most likely accounts for the higher sedation requirements in the NMBA group.”