Adverse pathophysiological consequences of poor pain management

Generally, if patient’s pain is well controlled they will recover quicker and be discharged sooner.


Misconceptions about post-operative pain

Pain Assessment

Principles of good pain management

Recommended Analgesics

Guidelines for post-operative intramuscular analgesia

Age Weight  Morphine Dose
 <70yrs  >65Kg  10mg
 <70yrs  <65Kg  7.5mg
 >70yrs  >65Kg  7.5mg
 >70yrs  <65Kg  5mg

Frequency : every 2 hours providing that:    

  1. Pain score 2 or 3
  2. Sedation score is 1 or 2
  3. Systolic BP >100mmHg
  4. Resp rate >10/min

Management of pain

  1. Pain score mild/no pain - consider change to oral analgesia
  2. Pain score moderate-severe - Repeat morphine dose 2 hourly for up to 3 doses and consider NSAID/paracetamol
  3. Pain score still remains moderate-severe - Clinical review +/- Acute Pain Service

Contraindications and side effects:

Guidelines for administration of all opioids via any route

Other methods of treating acute pain

Patient Controlled Analgesia (PCA)

PCAs are usually set up from theatre for patients undergoing intermediate - major surgery.  PCAs can also be set up for patients that are having regular IM injections of an opioid and NBM.  The system allows the patient to self-administer a small IV bolus of an opioid analgesic.  An IV loading dose needs to be given to establish analgesia before PCA is started.  The system has a lockout period built into it to allow the patient to re-assess their pain before administering a further dose.  The safety mechanism of the pump is that the patient MUST be the only person to press the button so if they become sedated they will not be able to press the button and overdose.

IV opioid infusions

A continuous infusion of opioid can be effectively used post-operatively, especially if patient is unable to use PCA.  Doses can be altered but it is not as safe as PCA and serious respiratory depression, regular monitoring required and may not be appropriate for general ward

Inhalation analgesia

Entonox (50% nitrous oxide and 50% oxygen) may be useful during short periods of post-operative pain (e.g. during physio, or removal of drains/dressings).  It cannot be used continuously because nitrous oxide causes bone marrow depression.

Local Anaesthesia

  1. Local Infiltration of wound site at the end of operation provides short term analgesia
  2. Nerve blocks are performed by the anaesthetist and require local anaesthetic to be injected around peripheral nerves and gives excellent pain relief
  3. Spinal anaesthesia blocks the nerves as they leave the spinal canal and before they separate into branches, resulting in analgesia in deep tissues as well as around the wound.  Hypotension is a serious side effect

Epidural analgesia

Complementary Therapies (to be used with analgesics)

  1. Reassurance.
  2. Education / Information.
  3. Relaxation.
  4. Imagery.
  5. Distraction.
  6. Hypnosis.
  7. Application of heat or cold.
  8. Massage.
  9. Aromatherapy.
  10. Exercise or Immobilisation.
  11. Transcutaneous Electrical Nerve Stimulation. (T.E.N.S.)
  12. Acupuncture.