postoperative pain

Etiology

• patients with cognitive impairment are at increased risk for development of postoperative chronic pain

Epidemiology

• usually underestimated & undertreated.
• ~70% of surgical patients experience moderate or severe post-operative pain

Complications

• stress response to surgery
  • retention of water & sodium
  • increase in metabolic rate
• respiratory complications
  • shallow breathing
  • cough suppression
  • lobular collapse
  • retention of pulmonary secretions
  • pneumonia
• cardiovascular complications
  • hypertension
  • tachycardia
  • increased myocardial work
    • yocardial ischemia
    • angina pectoris
    • myocardial infarction
• thromboembolic complications
  • reduced mobility due to inadequate pain management can lead to thromboembolism
• gastrointestinal complications
  • gastric stasis
  • paralytic ileus
• musculoskeletal complications related to prolonged confinement to bed
  • reduced mobility
  • muscle atrophy
• psychological complications
  • fear & anxiety
  • anger
  • resentment
  • hostility to medical & nursing personnel
  • insomnia
• opioids prescribed for postoperative pain often go unused or are unsafely stored & discarded

Management

• goals
  • to improve comfort & satisfaction of patient
  • to facilitate recovery & functionality
  • to reduce morbidity
  • to promote rapid discharge from hospital
• pharmaceutical agents
  • acetaminophen
    • reduces need for opioids
    • can alleviate mild post-operative pain as a single agent
  • NSAIDs
    • often effective after minor or moderate surgery
    • not sufficient as the sole analgesic agent after major surgery
    • often decrease the need for opioids
    • avoid long-term use in patients with atherosclerosis
    • ibuprofen is as effective as oral morphine, with fewer adverse effects, for home treatment of orthopedic postoperative pain in children
  • opioids
    • first-line treatment for severe post-operative pain
    • titrate dose against pain relief to minimize unwanted adverse effects
    • patient controlled analgesia more effctive than PRN or 'around the clock'
    • avoid in obese patients
    • avoid opiates in the immediate postoperative period
    • avoid unnecessary postoperative opiates in children
      • acetaminophen &/or NSAID use can minimized need for opiates
    • patient satisfaction with postoperative pain management not directly related to quantity of prescribed opioids
    • optimal duration of postsurgical opioid prescriptions 4-15 days depending upon procedure
      • 9 days for general surgical procedures (appendectomy, cholecystectomy, inguinal hernia repair)
      • days for women's health procedures (mastectomy, hysterectomy)
      • 15 days for musculoskeletal procedures (rotator cuff repair, anterior cruciate ligament repair, discectomy)
    • postoperative opioid prescribing diminished at University of Michigan after implementation of guidelines
    • opiates at hospital discharge only if patient required > 5 overnight opiate doses during hospitalization
      • 12 opioid tablets
      • 24 opioid tablets if patient required high opiate dose on last night of hospitalization
    • <=3 days of opiates is feasible for most postsurgical patients
      • may be associated with decreased chronic opioid use
    • tramadol with no fewer serious adverse effects than oxcodone or hydrocodone for treatment of postoperative pain after hip arthroplasty or knee arthroplasty
  • perioperative gabapentinoids of minimal benefit
    • time to resolution of postoperative pain is not shortened by gabapentin
    • coadministration of gabapentinoids with opioids associated with increased risk of opioid overdose & other opioid-related adverse events; however, absolute risk is low
    • perioperative gabapentin increases risk of delirium (RR=1.3), new antipsychotic use (RR=1.2), & pneumonia (RR=1.1) in elderly patients after major surgery
  • postoperative tramadol associated with higher risk for prolonged opioid use than postoperative hydrocodone or oxycodone
  • SSNRI benefit of moderate-certainty evidence
• regional analgesia
  • epidural analgesia, especially patient-controlled
    • provides superior post-operative analgesia, reducing complications & improving patient satisfaction
    • may diminish risk of post-operative delirium & respiratory complications (pneumonia) in elderly
  • neural blocks
  • wound infiltration with local anesthetic
  • continuous post-operative wound instillation of a local anesthetic via a multihole catheter placed intraoperatively by the surgeon
• multimodal anlagesia
  • synergistic effect of different analgesics &/or routes of administration
  • example: acetaminophen, NSAID, peripheral nerve block
  • may be technique of choice in the elderly
    • minimizes use of opioids
    • medication doses generally lower
• non-pharmaceutical approaches
  • periperative music, especially preoperative music reduces postoperative pain & postoperative analgesia use
    • does not reduce length of hospital stay

More general terms

• pain [odyn-]