Postoperative pain management
Aim
- minimise patient discomfort,
- facilitate early mobilisation and functional recovery
- prevent acute pain developing into chronic pain.
Mental health can affect a patient’s recovery and psychological vulnerability is predictive of severe postoperative pain.
Education before surgery reduces anxiety and improves patient satisfaction.
The choice of analgesia depends on the type of surgery the patient is having.
The choice of analgesic should be individualized based on the patient's pain severity, medical history, and potential risks.
Always consider a multimodal approach to pain management, combining different classes of analgesics to enhance pain relief while minimizing side effects.
Regional analgesic techniques eg Axillary Blocks, Forearm Blocks, are used routinely.
The amount of pain a patient suffers after surgery is related to the extent of tissue damage and the site of surgery.
Pain has both sensory and emotional components that interact to produce an overall 'pain experience'.
Unrelieved pain after surgery can interfere with sleep and physical functioning and can negatively affect a patient's well-being on multiple levels.
Good pain control is very important to prevent distress & avoid chronic pain.
Patients using opioids chronically can be identified because they may experience more pain than usual post operatively. Sometimes the “Pain Team” is consulted prior to surgery.
Predictors of postoperative pain
- Preoperative pain,
- Anxiety,
- Obesity,
- Fear of surgery,
- Psychological distress and type of surgery
- Previous Frozen Shoulder
- Restless leg Syndrome
Risk factors for chronic postsurgical pain
1. Preoperative factors
- Pain, moderate to severe, lasting more than a month
- Repeat surgery
- Fibromyalgia
- Irritable Bowel Syndrome
- Preoperative anxiety
- Female gender
- Younger age (adults)
- Workers’ compensation
- Genetic predisposition
- Catastrophising - magnifying the threat of pain
- Hypervigilance
2. Intraoperative factors
- Surgical approach with risk of nerve damage
3. Postoperative factors
- Pain (acute, moderate to severe)
- Radiation therapy to area
- Neurotoxic chemotherapy
- Depression
- Psychological vulnerability
Multimodal analgesia
Analgesics used in orthopaedic surgery range from non-opioid medications like paracetamol and NSAIDs to various opioids with differing potency and risk profiles.
Opioids delivered by patient-controlled analgesia (PCA) are the mainstay of systemic analgesia for the treatment of moderate to severe postoperative pain.
Unfortunately opioid-related adverse effects limit their use in many patients.
Analgesics that act by different mechanisms and at different receptor sites can be combined to produce additive or synergistic pain relief and can reduce opioid use.
- Include:
paracetamol
non-steroidal anti-inflammatory drugs (NSAIDs), including cyclo-oxygenase inhibitors
alpha2 agonists (clonidine, dexmedetomidine)
gabapentin and pregabalin13
ketamine
lignocaine infusions
peripheral nerve blocks, local anaesthetic wound infiltration and continuous wound infusion techniques.
Regional analgesia - Ultrasound-guided
-Axillary Blocks
- Forearm blocks
- Intermetacarpal Blocks
The duration of analgesia can be extended from hours to days
Procedure-specific analgesia
Each type of surgical procedure has its own unique postoperative pain characteristics and clinical consequences.
The choice of analgesia should be based on the evidence for that particular surgical procedure.
Pain management for day surgery patients remains the responsibility of the anaesthetist in consultation with Dr Myers.
The severity and likely duration of the pain should be assessed before discharge.
Analgesic regimens to address the pain include:
mild to moderate pain – paracetamol and/or ibuprofen
moderate to severe pain – oxycodone (5–10 mg 4–6 hourly) is preferable to codeine-containing medicines.
Neuropathic pain
Neuropathic pain can result from surgery
- is often difficult to treat
- may progress to persistent pain and disability.38
The diagnosis of neuropathic pain is based on the patient's description of pain (burning, shooting, spontaneous) and altered sensation (pins and needles, numbness), and on simple bedside tests for hyperalgesia (an exaggerated response to a painful stimulus) and allodynia (pain evoked by light touch or gentle pressure to deep tissues).
Intravenous ketamine (0.1 mg/kg/hour) or lignocaine (1–1.5 mg/kg/hour) can be used initially in patients who are 'nil by mouth'.
This can be followed by amitriptyline (10–25 mg orally) at night and gabapentin or pregabalin (Lyrica) titrated to response.
Acute postoperative pain can develop into chronic pain. This is defined as pain still present three months after surgery.
Reference P. Corke Australian Prescriber 2013 :36:205 2 December 2013