Trauma Pain Management

Donald M. Yealy

I. Basic Principles of Analgesia

Six basic principles of analgesia apply in all types of pain management.

Individualize the route and dose of analgesic.
- Patients respond differently to painful stimuli based on the type and severity of injury, psychological make-up, and ethnicity. In addition, individual analgesic requirements vary based on the time of day and previous use of analgesics or recreational substances. Although we offer starting doses (Table 15-1), amount and timing should be altered based on the response.
- Patients may have expectations of being completely pain-free; these expectations are often unrealistic. Provide adequate analgesia, defined as enhancing comfort to a tolerable level without side effect. The expected level of relief should be discussed with each patient to ensure understanding by both the provider and the receiver.
- Intramuscular injection offers no analgesic advantage over oral or intravenous administration due to erratic absorption and pain on injection. The variable absorption with IM injection (due to hydration, sympathetic tone, muscle site and time of day factors) limits the ability to titrate analgesia to need in a timely fashion, forcing the physician to estimate the correct dose (which is inaccurate in up to two-thirds of cases). This route should rarely be used and can be replaced with subcutaneous injections (which are less painful) in those who cannot tolerate oral medicines and without intravenous access.
Offer analgesics on a time-contingent basis during acute pain phases.
- Time-contingent dosing affords steady blood levels of analgesia, avoiding the wide fluctuations with “prn” dosing. It also avoids making the patient request medication, still allowing for refusal if not needed; this increases the sense of empowerment and satisfaction, augmenting the perceived analgesia.
- Time-contingent dosing is best for all analgesic preparations, including NSAIDs, acetaminophen and opioid analgesics. When providing oral analgesics, offer the medication based on the pharmacologic profile (e.g., hydrocodone or oxycodone every 4 to 6 hours around the clock) in the acute phase of injury. Parenteral opioids should be administered on a time-contingent basis as well, by hourly infusion (e.g., morphine, 1 to 2 mg/hr in opioid naive patients) or via a patient-controlled analgesia (PCA) device.

Opioids are the cornerstone of acute severe pain management.

Intravenous opioids offer the best opportunity to deliver rapid, titrated, adequate analgesia. Opioids, given in small increments every 5 to 10 minutes (e.g., morphine 2 to 5 mg, hydromorphone 0.5 to 1 mg, or fentanyl 50 to 100 mcg for most opioid naive adults), based on the pain and physiologic responses, remain the best agents for severe injury or initial postoperative pain. Oral opioids are inexpensive, effective, and tolerated well by patients with ongoing moderate to severe pain in the postoperative period or after the initial injury.

Table 15-1 Opioid Analgesics

	Equianalgesic dose (mg)		Starting oral dose
	Oral	IV^a	Adults	Children
Name	(mg and hour interval in adults)		(mg and hour interval) (mg/kg)
Pure agonists
Morphine	30 q3–4	5 q1–2	15–30 q3–4	0.3
Hydromorphone (Dilaudid)
Codeine^b	4–6 q3–4	1 q3–4	2–4 q4–6	0.06
Oxycodone (Roxicodone, Percocet, others)	120–130 q3–4	—	30–60 q3–4	0.5–1
Hydrocodone (Lortab, Lorcet, Vicodin, others)	30 q3–4	—	10–20 q3–4	0.3
Methadone	30 q3–4	—	10–20 q3–4	—
Levorphanol (Levo-Dromoran)	20 q6–8	5 q6–8	5–10 q6–8	0.2
Mixed agonist– antagonists	—	0.05 q0.5–1 (50 μg)	—	—
Nalbuphine (Nubain)	—	5 q3–4	—	—
Butorphanol (Stadol)	—	1 q2–4	—	—
^aAfter initial titration, which is done using this dose at 10 min intervals based on response; these are not recommended final doses but equipotent initial doses. ^bSedating and constipating in doses >60–90 mg; oxycodone and hydrocodone preferred. q, every.

PCA—using small patient-triggered boluses of an opioid (usually morphine) every 6 to 10 minutes maximum, with “lock-out intervals” to prevent excess, allows safe and effective relief. PCA requires some initial “loading” – relief gained from bedside titration – before instituting patient maintenance. It can be combined with low dose infusions to decrease needs safely and augment relief. PCA care
paths/plans are best developed together with acute pain practitioners based on local resources.

Combination therapy affords the best analgesia, especially in mild to moderate pain syndromes and after acute severe pain is initially controlled.

Include an NSAID with an opioid whenever possible to provide analgesia by two different and synergistic methods. Avoid if neurologic surgery, existing bleeding disorder or large volume blood loss, or if other anticoagulant/antiplatelet agents are used. All NSAIDs have similar effects when given in equipotent doses—we recommend using the least expensive drug/route for the shortest interval (Table 15-2).

Ketorolac (30 to 60 mg i.m. or 15 to 30 mg i.v.) is the only NSAID available for parenteral use. It is no more effective than oral ibuprofen (600 mg) or indomethacin (50 mg), although much more expensive than these NSAIDs and generic morphine or hydromorphone. Ketorolac should be reserved for short-term use (<3 days) in those patients who are unable to take an inexpensive NSAID orally.
Newer selective oral NSAIDs (termed COX-2 inhibitors) offer analgesic and anti-inflammatory effects similar to traditional NSAIDs with a lower frequency of GI side effects and less anti-platelet effects. However, they are more expensive than traditional NSAIDs, and do not avoid GI or renal side effects; they should be reserved for those patients intolerant of traditional NSAIDs or at high risk for complications who need prolonged therapy. Finally, they increase the risk of cardiovascular events; given the complex issues and limited need in acute pain (compared to other agents), these are not recommended currently for acute pain management.

Table 15-2 Non-opioid Analgesics/NSAID

Drug	Usual adult dose	Usual pediatric dose	Comments
Oral
Acetaminophen	650–1,000 mg q4h	10–15 mg/kg q4h	Acetaminophen lacks anti-inflammatory activity
Aspirin	650–1,000 mg q4h	10–15 mg/kg q4h^a	The standard against which other NSAIDs are compared. Inhibits platelet aggregation irreversibly (lasts 2 wks); may cause postoperative bleeding
Ibuprofen (Motrin, others)	400–600 mg q4–6h	10 mg/kg q6–8h	Available as several brand names and as generic
Naproxen (Anaprox, Naprosyn others)	500–550 mg initial dose followed by 250–275 mg q6–8h	NA	Available as several brand names and as generic
Parenteral
Ketorolac tromethamine (Toradol)	30–60 mg i.m. or 15 mg i.v. initial dose followed by 15 or 30 mg q6h		Parenteral use should not exceed 5 d
^aContraindicated in presence of fever or other evidence of viral illness. With the possible exception of trisalicylate and salsalate, all NSAID exhibit reversible antiplatelet effects. Also, these doses are associated with peak analgesic effects, although increased doses cause increased anti-inflammatory affects along with more side effects. NSAID, nonsteroidal anti-inflammatory drug.