Sam and I have had a few transports recently that have been challenging from a sedation standpoint, either because of difficulties at the sending facility, complex pathophysiology, or poor hemodynamics. So Scott Weingart’s most recent podcast entitled A New Paradigm for Post-Intubation Pain, Agitation, and Delirium is rather timely. There are numerous studies showing that what we have been doing, particularly in the transport setting, leads to delirium and thereby to poor outcomes along the lines of brain injury and mortality. Scott points out that much of the damage is done in the first four hours of care. It just so happens that this is generally the window within which we work.
Adapting Scott’s recommendations to our environment, we have a number of tools available. The first principle is that analgesia should be the first priority in intubated patients rather than sedation. Scott recommends a fentanyl drip (1-1.5 mcg/kg/hr) with boluses of 50 mcg titrated to patient comfort as the first part of an appropriate sedation and analgesia package. If a fentanyl drip is not practical, hydromorphone by bolus is a second choice. Scott talks about the relative merits of synthetics, but certainly morphine by bolus is an option here as well (as in, for example, a recent transport where a patient had received amiodarone for arrhythmia and we had specific orders not to administer fentanyl).
When pain is controlled, the next step is sedation. However we’re not talking about “snowing” our patients or paralyzing them. The target should be a Richmond Agitation Sedation Scale of a little less than 0. In more familiar terms, this is about equal to “V” on the AVPU scale–the patient should awaken to verbal stimulus. The idea is to preserve a degree of wakefulness so as to allow the patient to maintain their normal sleep architecture.
Midazolam or other benzodiazepines are not the agents of choice here, as they are associated with disruptions in sleep patterns and the aforementioned delirium. An agent known as dexmedetomidine is advocated at the first choice. While I am not familiar with this agent and certainly have never seen its use in the transport setting, there are some more familiar substitutions. Propofol is recommended as a second choice to dexmed, with pressor agents administered to support hemodynamics as necessary. In truly unstable patients who have poor hemodynamics despite pressor therapy, ketamine infusion is recommended.
Please see the podcast as it discusses these concepts in greater detail, and gives insight to the negative impact that delirium and oversedation is having on patient outcomes.
Here is the ICU Delirium and Cognitive Impairment Study Group’s recommended sedation protocol, for reference.