Update on ICU sedation

April 03, 2020

The state of pharmacological sedation in the ICU is ever changing. Traditionally, patients who were mechanically ventilated in the ICU were kept deeply sedated with continuous depressant infusions to maximize ventilator synchrony and decrease discomfort that may arise during critical illness. "This convention of heavy depressant use contributed to a reflex familiar to many intensivists," says Dante N. Schiavo, M.D., Pulmonary and Critical Care Medicine at Mayo Clinic in Rochester, Minnesota. "After intubation of a patient in the ICU, the care team might ask, 'What are we going to use for sedation?'"

Data from the turn of this century suggested that continuous infusions of sedative medications were associated with worse clinical outcomes and more untoward effects compared with intermittent dosing.

Another practice in ICU sedation that developed in this century was daily sedation interruption (DSI), or "sedation holidays," as data suggested that use of DSI improved outcomes and further reduced untoward effects of depressant medications.

Subsequent data on DSI in patients already on sedation algorithms (as opposed to continuous infusions) with frequent assessments of necessity built in did not show as robust findings to support DSI. As reported in Critical Care in 2016, a head-to-head trial of DSI compared with sedation algorithms was even stopped early because of worse outcomes in the DSI group. "These data suggest that what is most critical is some compulsory tool to frequently assess whether sedation is needed, as opposed to the DSI itself," says Dr. Schiavo.

Also contributing to decreased enthusiasm for aggressive use of sedative medication in the ICU is a study published in 2020 in The New England Journal of Medicine that examined a strategy of no planned sedation versus a strategy of light sedation. In this well-designed, multicenter, randomized clinical trial, 710 adult patients in ICUs who were not severely hypoxemic and were expected to receive mechanical ventilation for more than 24 hours were randomized into a strategy of no sedation versus light sedation, defined as pursuit of a Richmond Agitation and Sedation Scale (RASS) score of -2 to -3.

The light sedation arm featured many of the tenets of ICU sedation learned from the prior 20 years of data:

Patients were not kept deeply sedated.
DSI was used.
A protocol was followed for sedation use and resumption after DSI.

Both groups were well balanced except for a higher Acute Physiology and Chronic Health Evaluation (APACHE) II score indicating a greater predicted mortality in the nonsedation group, and both groups of patients were permitted opioid narcotics for analgesia. Between the groups, there was no significant difference in mortality, length of hospital or ICU stay, ventilator-free days, or acute kidney injury.

Dr. Schiavo concludes: "At Mayo Clinic, the mechanical ventilation order set no longer includes mandatory use of sedative medications. When pharmacological sedation is required, the standard is light sedation with a protocolized goal RASS score of 0 to -2 with DSI or documentation of why it was forewent. We encourage our team to use the term "sedation-analgesia-anxiolysis," or SAA, rather than ICU sedation, to better emphasize that use of depressant medications should be in response to a specific type of discomfort rather than a routine ICU therapy.

"Furthermore, a clinical trial currently underway is examining whether a strategy of patient-controlled SAA versus usual protocolized SAA affects short-term (anxiety, delirium, duration of mechanical ventilation) and long-term (functional status, psychological well-being, health-related quality of life) outcomes. The correct answer to 'What are we going to use for sedation?' should be 'Only what the patient needs'. And for some patients that may be nothing at all."