Tackling The Most Commonly Abnormal ED "Vital Sign"

The Gist:  Pain is subjective and ubiquitous in the emergency department (ED).  Treatment of pain in the ED varies widely between practitioners and is often not formally taught as part of the curriculum, lending this aspect of EM to often be characterized as "art."  I came up with a rough pain control algorithm for acute pain or recurrent pain as I get started in Emergency Medicine, roughly based on an evidence based template from Lipp et al (note: I'm not an expert and this is far less useful for complex pain complaints such as migraine and does not address procedural sedation).

Check out this article by Dr. Leon Gussow of The Poison Review on the darker side of the emphasis of pain as a Joint Commission mandated vital sign in the ED.  

Regional Analgesia - It appears that, with the aid of ultrasound, nerve blocks are increasingly common in the ED. These are great for orthopedic and soft tissue injuries, and there seems to be a movement to increase utilization for hip fractures (Haslam et al, Haines et al)

Upsides:   Patient may not need sedation or sedating analgesics, thereby preserving mentation, respiratory drive, and hemodynamics.  Great, targeted analgesia 

Downsides: Potentially time consuming, invasive, disrupts neuro exam, potential for systemic toxicity (use ultrasound!).  

Pearls: 

• Practice these on an anesthesia rotation. 
• Use ultrasound:  Ultrasound Guided Nerve Block Education, Part I, Part II, Femoral Nerve Blocks, Sonoguide.com.  Sonospot.com has many useful posts on publications and tipstricks for ultrasound guided nerve blocks (searchable).
• Perform a solid neurovascular exam before performing the block.  Monitor patients afterward. 
• Work with consultants (ex: ortho for blocks for femur and hip fractures).

Non-opioid Analgesics - Acetaminophen (APAP) and Nonsteroidal anti-inflammatory drugs (NSAIDs) are effective for mild to moderate pain (2).

Upsides:  NSAIDs are especially useful in prostaglandin-potentiated conditions, such as dysmenorrhea, gout, rheumatoid arthritis, and ureteral colic (1, 2).  APAP is safe in pregnancy (1,3).

Downsides: 

• Dose-limiting adverse effects on the gastrointestinal tract (NSAIDS). Must be cognisant of total APAP load across all medications so 4g/day is not exceeded  (1,2).
• NSAIDS may have untoward effects in patients on other medications including: warfarin (bleeding), diuretics/lithium/ACE-I/methotrexate (renal insufficiency and subsequent therapeutic index issues) (1).
• NSAIDS may induce or worsen renal insufficiency in elderly patients, those with pre-existing renal disease, or in the setting of dehydration (3).

Pearls:

• Ceiling dose for analgesia from ibuprofen lies in a 400mg dose (higher ceiling dose for anti-inflammatory effect), discussed in this blog post by Dr. Chris Bond. 
• Parenteral keterolac offers no better analgesia compared with ibuprofen or naproxen, and costs much more (Dr. Bond's post, Arora et al, 2, 4).
• IV APAP, used internationally with success, has made an appearance in the US over the past couple of years, but comes at a cost of more than $10 USD per 1g dose without drastically better analgesia.  The focus on IV APAP is the potential opioid sparing effect (Kwiatkowski et al)

Opioid Analgesia - These get the most attention in the ED, partially due to the focus on abuse.  There are many drugs in this category but they tend to fall into groups:  

• Opiates (derived from the opium plant) - morphine, codeine
• Semi-synthetics - hydrocodone, oxycodone, hydromorphone, oxymorphone, buprenorphine, heroin 
• Synthetics - fentanyl, alfentanil, sufentanil, remifentanil, methadone, tramadol, propoxyphene, meperidine

Upsides: 

• Good analgesia for visceral and somatic pain
• Many opioids are titratable

Downsides:  

• Respiratory depression
• Histamine release - pruritus, flushing, hives, and/or hypotension.
• Released from mast cells, may be mistaken for allergic reaction (which has an immunologic component). 
• Opiates tend to cause more histamine release than the semi-synthetics and synthetics (6).
• Potential for abuse/dependence

Pearls:

• IV morphine starting dose for moderate-to-severe pain = 0.1 - 0.15 mg/kg. 
• Patients in severe pain or opioid-tolerant, will not obtain adequate analgesia with a single 0.1-mg/kg dose and may require additional doses.
• Oral opioids (hydrocodone) may take 30-60 min to achieve analgesia (3). 
• This may be off-set by time to establish an IV, etc (Miner et al)
• Oxycodone starting dose 0.125 mg/kg (Miner et al) in most patient populations.
• IV hydromorphone starting dose 1mg, with an additional 1mg dose if analgesia not achieved (5).
• less renal clearance so may be better in patients with renal insufficiency (2,4)
• less histamine release (6).
• When discharging a patient home with opioids, consider checking the state monitoring program online (ACEP clinical policy, Level C).  This can be time consuming and is generally limited to a single state.  Listen to Dr. Scott Weingart's Practical Evidence podcast on this.
• When prescribing, prescribe a short course (ex: 3 days).
• It's widely accepted that analgesia doesn't "mask" surgical pathology, which was a historic concern in patients with suspected intra-abdominal pathology (1-4).

Poppies in Turkey

References:

1.  Miner J, Paris P, Yealy D.  "Pain Management."  Rosen's Emergency Medicine.  7th ed. p 2410-2428.  
2.  Lipp C, Dhaliwal R, Lang E.  Analgesia in the emergency department: a GRADE-based evaluation of research evidence and recommendations for practice.  Critical Care 2013, 17:212 
3.  Ducharme, J.  "Acute Pain Management in Adults."  Tintinalli's Emergency Medicine.  7th ed.  p 259-265.

4.  Heins, Alan. Focus On: Effective Acute Pain Management.  October 2005.  ACEP. 

5.  Chang AK, et al. Randomized clinical trial of the 2 mg hydromorphone bolus protocol versus the "1 + 1" hydromorphone titration protocol in treatment of acute, severe pain in the first hour of emergency department presentation. Ann Emerg Med. 2013 May 16. 

6.  Li, F.  Pharmacologically Induced Histamine Release: Sorting Out Hypersensitivity Reactions to Opioids