Management of Acute Pain in Trauma 1
By Dr. Saman Nanayakkara
It is well accepted that effective management of pain in the acute trauma setting enhances recovery of patients and reduces morbidity and mortality. Injured patients often experience considerable pain while it goes unnoticed by the emergency team attending to critical injuries of the patient. When trauma patients reaches the hospital their level of consciousness may be impaired, they may be bleeding, may be hypovolemic, coagulopathic, hemodynamically unstable and may have compromised airway or breathing. All these will distract the physicians from the fact that the patient is in excruciating pain and needs immediate pain relief. A patient in severe pain may be very anxious, agitated, uncooperative with history taking, examination and investigations or various procedures. Pain will hinder mobilization and proper positioning, which can affect achieving hemostasis, propping up for better oxygenation, splinting limb fractures, log rolling, gaining intravenous access, bladder catheterization etc. Therefore, pain should be objectively evaluated in all trauma patients soon after assessing airway, breathing, circulation and disability and should be treated promptly.
This chapter focuses on means of providing analgesia with its practical aspects and implications etc. after admission to the OPD or a surgical casualty ward in the context of facilities available in Sri Lanka.
Deleterious effects of pain on an acutely injured patient are:
1. Tachycardia, hypertension and tachypnoea due to activation of the sympathetic nervous system.
2. Arrhythmias and angina in patients who are at risk. E.g. patients with ischemic heart disease
3. Exaggerated stress response to trauma including increased release of catecholamine, cortisol, antidiuretic hormone, growth hormone, adrenocorticotrophic hormones and activation of renin-angiotensin system. This response would activate various metabolic and neurohormonal mechanisms including release of cytokines and acute phase reactants finally leading to hyperglycemia, protein catabolism, lipolysis, immunosuppression and impaired coagulability etc.
4. Reduced mobilization with increased tendency for deep venous thrombosis and pulmonary embolism.
5. Decreased depth of breathing leading to basal lung atelectasis, ventilation-perfusion mismatch, hypoxia and increased nosocomial lung infections.
6. Reduced gastrointestinal motility.
7. Salt and water retention
8. Later leading to development of chronic disabling neuropathic pain, post-traumatic stress disorder etc.
Reasons for poor management of pain in trauma patients
1. Under assessment of pain.
2. Lack of training to emergency staff on pain management.
3. Concerns about hypotension and respiratory depression due to analgesics.
4. Concerns about the interference with the assessment of level of consciousness in head injury patients, especially by opioids.
5. Undue worries about addiction to analgesics, especially opioids.
Advantages of effective pain relief in trauma patients
1. Avoidance of pain related complications mentioned above
2. Enhanced recovery and reduced hospital stay
3. Decreased incidence of post-traumatic stress disorders (PTSD) and various chronic pain syndromes
4. Early rehabilitation and early return to normal life
Stages in Trauma
Analgesia is needed in all stages of trauma management including extrication from the site of trauma, during transfer to the hospital, in emergency departments/ outpatient departments of the hospitals, in the pre-operative stage in the surgical casualty ward and in the post-operative setting.
In the developed world, trained paramedics of rescue teams who have specialized in extricating trauma victims use intramuscular ketamine and Entonox inhalation when necessary during extrications. During transportation, strong opioids like morphine can be used subcutaneously or intramuscularly. If the patient’s airway is secured, breathing is adequate and attended, intravenous access is established and haemodynamically stable intravenous morphine or fentanyl can be used.
Multi-Disciplinary and Multi Modal Analgesia
Achieving effective pain relief is a challenge in the setting of trauma. Medical staff is confronted with an unknown patient in whom they have several concerns like, not knowing all possible injuries, haemodynamic and respiratory instability, anxious and worried patient and family members and restlessness and agitation of patient etc. In a situation like this, a single dose of a single analgesic is not going to take care of pain, especially because acute pain is very intense and disabling. The attending staff needs to integrate available resources (pharmacological and nonpharmacological strategies) to carry out efficient pain relief.
Non Pharmacological Strategies
Four strategies described below are useful adjuncts to pharmacological methods of analgesia. However, the expertise and instruments necessary for those are not freely available in the trauma setting in the OPDs in Sri Lanka. Patients also need to have some awareness and belief in these methods if they are to be useful in them. These needs should be addressed in future training of emergency staff in Sri Lanka.
1. Psychological interventions
Anxiety, fear and apprehension contribute significantly to psychological stressors associated with pain and all these can contribute to development of post-traumatic stress disorders. Therefore, explaining the nature of injuries and the analgesic plan, and allaying anxiety are essential steps in pain management. These would not take a lot of time and do not need sophisticated medical equipment. Moreover, it will make the initial management much easier.
Cognitive approach allows patients to view inner thoughts as modifiable behavior which can affect perception of pain. Distraction strategies like teaching the patient to imagine that he is comfortable or in an imaginated happy-relaxed location is an accepted strategy.
Relaxation techniques like muscle relaxation and deep regular breathing will help to reduce the sympathetic nervous system outflow.
This includes suggestions to alter the perception or cognition of pain and suggestions to dissociate from pain and discomfort.
3. Transcutaneous Electrical Nerve Stimulation (TENS)
This has been very effective in alleviating somatic pain especially with burns and uncomplicated rib fractures. It also helps to reduce the dose of other analgesics.
4. Acupuncture : Not discusses in details
Different groups of drugs used as analgesics and adjuvant drugs are discussed in Chapter 2 in Pain Management: Current Concepts Part I. Only the applications in acute pain management setting will be discussed here. The analgesics and the adjuvant drugs can be classified broadly into several categories.
1. Simple analgesics like paracetamol and non-steroidal anti-inflammatory drugs – NSAIDs (non-selective NSAIDs like ibuprofen, aspirin, diclofenac sodium, and selective COX-2 inhibitor NSAIDs like celecoxib etc.)
2. Intermediate potency analgesics like tramadol and codeine
3. Strong analgesics like morphine, pethidine and fentanyl
4. Local anesthetics
5. Regional anesthesia
8. Adjuvant drugs
When used in the correct dosage, regularly every 6 hours, paracetamol acts as an effective pain reliever. It can be given oral, nasogastric or rectal routes (intravenous form is not available in Sri Lanka) 60mg/kg/day in 4 divided doses. Paracetamol can be started on all trauma patients regardless of the site, severity or complexity of the trauma. It can be given with other oral analgesics even to a patient awaiting general anesthesia for surgery with a sip of water. Paracetamol is very cheap, freely available and has only a very few absolute contraindications (in known hypersensitivity and liver impairment /failure). For children, it can be given at 10-15mg/kg/dose every 6 hours.
NSAIDs work very well for mild to moderate somatic pain (skin, muscle, tendons, joints and bone pain), especially when combined with paracetamol. These again are cheap, freely available, have the added advantage of anti-inflammatory property and can be given to most of the trauma patients. Common contraindications for non-selective NSAIDs are known allergy, peptic ulcer disease, gastritis, renal impairment, severe heart failure and, increased bleeding tendency. If the oral route cannot be used diclofenac sodium is available in the rectal form. Rectal insertion needs patient’s consent. COX2 selective NSAIDs like celecoxib (200mg twice a day) are associated with a lower risk of serious upper gastro-intestinal side effects. COX2 selective NSAIDs are contraindicated in ischemic heart disease, cerebrovascular disease, peripheral arterial disease and moderate to severe heart failure.
Ibuprofen can be administered at a dose of 200-400mg 3 times a day (max. 2.4g/day) and for children 5-10mg/kg /dose, 3 times a day. Diclofenac sodium can be given orally/rectally 0.75-1mg/kg/dose, 2-3 times a day, both for adults and children.
Paracetamol and NSAIDs are usually not sufficient by themselves to treat severe pain. However, their safety profile makes them very helpful adjuncts in handling pain due to trauma especially when the two are combined. Care should be taken not to use two NSAIDs together and to select the best NSAID that would suit a particular patient. Among NSAIDs, ibuprofen has the best side effect profile but it is the least effective, and hence, would be ideal for minor injuries combined with paracetamol. Aspirin and diclofenac are stronger analgesics but are associated with more side effects.
Intermediate potency analgesics
This is a weak opioid agonist and also acts on serotonin receptors in the spinal cord. Tramadol also has effects on adrenergic pathway. It is good for moderate and moderately severe pain due to trauma. It is available as oral, rectal and parenteral forms. With parenteral administration it acts within a few minutes, peak effect comes in about 15-30 minutes and acts for about 3-6hrs. There is no respiratory depression and cardiovascular side effects are minimal. It causes less constipation and has less addiction potential compared to conventional opioids. Dizziness, dry mouth, sedation, nausea, sweating and vomiting are some unpleasant effects of tramadol.
Tramadol is the preferred analgesic for spontaneously breathing head injury patients as it has very little respiratory depressant effect. A dosage of 0.15mg/kg can be given every 3-5 minutes till the patient is comfortable. For postoperative patients, even oral tramadol can be given 25-50mg every 30 minutes till the patient is comfortable. It should not be used with pethidine and HT3 antagonists like ondansetron because of the risk of serotoninergic syndrome (characterized by autonomic symptoms like tachycardia, hypertension, mydriasis, sweating, mental symptoms like confusion, hallucinations, disorientation, agitation and musculoskeletal symptoms like shivering, hypertonia and tremors etc). These side effects can occur with rapid IV injection also.
Codeine is a low-efficacy opioid effective for mild to moderate pain and is available in oral and IM forms. (IM preparation is not available in Sri Lanka.) The dose is 30-60mg every 4-6hrs up to a daily maximum of 240mg. Codeine is an ingredient of some compound analgesic preparations like panadeine and can be given as 2 tablets every 6 hourly for an adult. Constipation is common with long term use.
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Sri Lanka Association for the Study of Pain
The Sri Lankan Chapter of the International Association for the Study of Pain