Update: Analgesia and Sedation in the Intubated ED Patient
- Feb 21st, 2014
- Rachel Shard
Analgesia and sedation in the intubated emergency department patient is a very important, yet often overlooked element of critical care management in the ED. Patients, besides bearing the incredible discomfort of having a hard plastic tube sitting in their trachea, cannot be ventilated effectively or efficiently without adequate comfort measures. However, placing patients in deep sedation has been shown to possibly increase delirium, ventilator dependent days, and mortality in patients intubated for greater than 24 hours. Despite all of the differing diagnoses patients are intubated for, emergency clinicians often use the same drug regimens. What is the best strategy for the patient?
Step one is determining the depth of sedation / analgesia the patient requires. The most commonly used scale is the Richmond Agitation Sedation Score (RASS). +4 indicates the patient is combative, while -4 indicates the patient is in deep sedation. Current recommendations suggest the goal of sedation should be -2 to +1 (light sedation to mild restlessness). Targeting light sedation within the first twelve hours of intubation decreases morbidity and mortality. Furthermore, in one study, allowing light sedation has been shown to decrease delirium. This intervention has led to less physical restraint use and has not altered the incidence of self-extubation. These measures likely lead to improved patient safety.
The clinician’s primary strategy should be to optimize analgesia. This goal could ideally be achieved by bolus doses of opioids, coupled with an infusion at a lower basal rate. Increase the infusion rate slowly and with small increments while providing boluses of pain medication. This strategy will allow the clinician to achieve the lowest effective basal rate without overmedicating the patient. Current research recommends fentanyl or remifentanyl as first line, because these medications are quick-acting and their metabolites do not accumulate during renal failure (morphine, dilaudid). If a RASS of -2 to +1 can be achieved with analgesia alone, avoid sedative agents altogether.
If the clinician feels pain has been adequately treated, yet the patient continues to appear uncomfortable, sedatives should be employed. Commonly used sedatives include benzodiazepines, propofol, and dexmedetomidine. Benzodiazepines are cost-effective and widely available. However, they are also lipophilic, meaning they accumulate in fat. This quality, particularly in an increasingly obese patient population, can prolong sedative effects, leading to an increase in intubated days. These medications have also been cited as contributors toward ICU delirium and, if the patient has been on a prolonged infusion, may lead to withdrawal when stopped.
Many experts prefer propofol to benzodiazepines, as propofol has been shown to decrease intubated days. However, in bolus doses propofol may lead to hypotension. Propofol has also been known to cause an “infusion syndrome” in rare cases – more likely at high doses or when used for an extended period of time. If utilizing doses greater than 5 mg / kg/ hr or for greater than five days, be vigilant. This syndrome is characterized by hyperkalemia, hypotension, bradycardia, acidosis, and rhabdomyolysis (consider checking a pH, BMP, and CK).
Dexmedetomidine is a selective alpha-2 adrenergic agonist that produces both sedative and analgesic effects. It may also cause hypotension and bradycardia at higher doses. In one trial, dexmedetomidine was found to decrease the amount of ventilator days and found patients were more easily aroused and better able to communicate pain than with comparable doses of propofol or midazolam. Currently, dexmedetomidine has not been approved by the FDA for infusion lasting greater than 24 hours. However, this medication has been utilized for longer periods of time in both Europe and Japan and is likely safe to use for greater than 24 hours duration. Use caution in patients with hypotension, bradycardia, sick sinus syndrome, and heart blocks.
In short, after intubating the emergency patient, be sure to provide adequate analgesia. First line agents are fentanyl / remifentanyl. After the clinician has ensured analgesia, move on to sedative agents. Propofol and dexmedetomidine are likely better first line agents than benzodiazepines as they have been shown to decrease the amount of ventilator dependent days and ICU delirium. Aim for light sedation, ie RASS of -2 to +1. Targeting light sedation decreases morbidity and mortality, ventilator dependent days, and delirium. Light sedation also allows patients to better communicate pain and has not increased the rate of self-extubation.