Postoperative pain management

Learning objectives

Adequate postoperative pain management is essential to enable a quick return to normal function
Uncontrolled pain increases sympathetic activity and the stress response, leading to multisystem consequences (e.g., hyperglycemia, immunosuppression, increased risk of myocardial ischemia)
Pain after abdominal or thoracic surgery can lead to splinting of the diaphragm and chest wall, resulting in decreased lung volumes, atelectasis, poor cough, sputum retention, infection, and hypoxia
Pain can reduce mobility and increase the risk of thromboembolism
Psychological effects: anxiety, feeling of helplessness
Untreated or inadequately treated postoperative pain can lead to chronic pain
Traditionally, opioids were the standard treatment for postoperative pain
Today, multimodal approaches for pain management are the treatment of choice

Perform pain assessment at regular, frequent intervals and after every intervention
The severity of pain and the effectiveness of analgesia determine the frequency
Record pain as the fifth vital sign
Assessment includes:
- Site, circumstances associated with onset
- Character
- Intensity (at rest and on movement)
- Associated symptoms (e.g., nausea)
- Effect on activity and sleep
- Relevant medical history
- Other factors influencing the patient’s treatment
- Current and previous medications and analgesic strategies
Severity scales:
- Unidimensional
  - Numeric (numeric rating scales, visual analog scale)
  - Categorical (verbal descriptor scale)
- Multidimensional (less useful in acute postoperative pain)
  - McGill Pain Questionnaire
  - Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) can be used to identify those at risk of developing chronic neuropathic pain
- Pictorial and behavioral scales may be needed for children or cognitively impaired patients
  - FLACC scale
  - Abbey pain scale

Opioid-dependent patients (long-term opioids for chronic pain, opioids for cancer pain, recreational use)
- Manage patient expectations
- Provide adequate analgesia
- Prevent or manage withdrawal symptoms
Acute neuropathic pain after surgery
- Incidence depends on type of surgery (e.g., 85% following limb amputation)
- Pre-emptive analgesia (regional techniques, ketamine, administration before start of surgery) may be helpful
- Maintain a high index of suspicion for patients at high risk
- Treatment is extrapolated from chronic neuropathic pain treatment: Tricyclic antidepressants, ketamine, anticonvulsants, lidocaine, and tramadol may have a role