Author: Thomas Rosenthal
Although there was a statistically significant difference between daytime and nighttime use of sedatives and analgesics among mechanically ventilated ICU patients, this difference was not clinically meaningful.
The retrospective cohort study, presented at the 2018 annual meeting of the Society of Critical Care Medicine (abstract 57), found that adult patients admitted to the medical and surgical ICUs at Beth Israel Deaconess Medical Center, in Boston, between 2008 and 2012, received more benzodiazepines and opioids at night, while propofol and dexmedetomidine use was higher during the day.
The single-center study included 2,277 adult patients who were mechanically ventilated for more than 48 hours. Sedative/analgesic drug use was computed for each shift (7 a.m.-6:59 p.m. and 7 p.m.-6:59 a.m.) and reported as opioids (morphine equivalents), benzodiazepines (lorazepam equivalents), propofol and dexmedetomidine.
“We feel that this is likely a reflection of institutional adoption of targeted sedation strategies, adoption of validated sedation assessment scales, and overall recognition of the adverse effects associated with deeper levels of sedation and excessive use of these medications,” said Somnath Bose, MD, an anesthesiologist at Beth Israel Deaconess Medical Center, and an instructor of anesthesiology at Harvard Medical School, Boston, who was the lead author of the study.
Dr. Bose said it has been shown repeatedly that excessive sedation is associated with bad outcomes. “So, all centers should be proactive about minimizing use of sedatives,” he said. “Having a protocol reflective of such an approach might not only empower the caregivers at the bedside but also aid in implementation of the strategy.”
The study compared daytime and nighttime use of each drug and reported cumulative differences. However, Dr. Bose said, “We cannot definitively rule out subtle day–night differences.”
Nicholas Sich, MD, a general surgeon at Abington Hospital, in Abington, Pa., who was not associated with the study, said researchers indicated that they found no clinical difference, and the findings can be related to other considerations, such as choosing one drug over another due to its inherent properties. “Even though patients do receive more medication at night, this is likely because of their intubation times and drug choice,” Dr. Sich explained.
For example, physicians may turn to one drug for its faster metabolizing time. “Using propofol extensively, even if you oversedate a patient, will likely not translate to a clinical manifestation because, once you turn it off, patients will still wake up in the next hour or two, if not sooner,” Dr. Sich continued. “So, for 48 to 72 hours, propofol is the go-to drug of choice for many intensivists.”
Dr. Sich said if the researchers had used continuous benzodiazepines from the start to the end of the study, “I believe they would have seen the same diurnal effect of oversedation at night, and it would have certainly manifested clinically. This is why no one uses continuous benzodiazepine infusions anymore.”
Dr. Bose agreed that propofol is the most common go-to sedative, despite its side effects at high doses. “Prolonged infusion of propofol can lead to propofol infusion syndrome and hypertriglyceridemia. However, these have not been seen commonly if used in modest doses. Although patients on prolonged propofol infusions usually wake up relatively quickly, practitioners should still be cognizant of the increased context-sensitive half-time of the drug following prolonged usage. The proven deliriogenic potential of benzodiazepines is another reason for practitioners to avoid their long-term use for sedation.”
Dr. Sich said he suspected one of the leading causes of oversedation at night is patients are “asleep,” and they are not awoken every hour for a thorough assessment of pain control and sedation levels. “That makes sense for a lot of reasons from a practical standpoint,” he said. “Why wake a patient you are not planning to extubate from sleep at night if they’re sleeping comfortably without pain or complaint?” However, he said, in practice this often means leaving their continuous infusions running, which almost certainly oversedates patients and keeps them out of the target Richmond Agitation–Sedation Scale -1 range.
Although some believe that high sedation levels at night can be equivocated to sleep, for Dr. Bose, it’s really a sign to reduce sedative medications. “This is a commonly held belief among nighttime staff that more sedation at night leads to much needed restorative sleep,” he said. “However, it must be noted that sedation and sleep are not exactly interchangeable—another reason to minimize sedation overnight and maintain a lighter depth of sedation.”