Pain Management The management of pain is important not just for humanitarian also to improve and reduce postoperative complications. Pain assessment: visual, verbal, numerical, Faces pain scale.
World Health Organization (WHO) Step Ladder Approach • Severe Pain 7-10/10 • Potent opioids (e.g. • morphine) +/- • non-opioids • Moderate Pain 4-6/10 • Weak opioids +/- non- • opioids (e.g. paracetamol) • Mild Pain 1-3/10 • ASA, Paracetamol, • NSAIDS
Routes of analgesic delivery Oral: • Simplest route available • The bioavailability is limited to 1st pass metabolism • The oral route is not suggested following major surgery due to potential delays in gastric emptying
The non-steroidal anti-inflammatory drugs are probably the most widely used group of drugs in the world. Indications for their use are: • acute pain following surgery • renal colic • chronic pain arising from inflammation • opioid-sparing • prophylactic treatment of cardiovascular and thrombotic related diseases • antipyretic effect. Side-effects 1. Gastric toxicity. 2. Renal complications. 3. Haemostatic impairment. 4. CNS toxicity. 5. Dermatological effects. 6. Aspirin-induced asthma. 7. Haematological effects. 8. Hepatotoxicity. 9. Teratogenic effects. 10. Drug interactions.
Intermittent subcutaneous or intramuscular injection Advantages: • Safe if it administered more regularly • Familiar practice • Gradual onset of side-effects • Inexpensive.
Disadvantages: • Painful injections • Fluctuating plasma concentration • Delayed onset of analgesia
Intravenous bolus • For the management of severe acute pain. • It gives the quickest onset and repeated doses can be titrated against effect. • Close supervision of the patient is required. • This method is not appropriate for continuing pain management at ward level
Intra nasal bolus • Efficacy and speed of action are similar to that I.M. • It offers an alternative method of administration for areas such as emergency department and pediatric units
Continuous intravenous infusion Advantages: • Rapid onset of analgesia • Steady-state plasma concentrations • Painless • Pain control may be superior to PCA spc. For major surgery
Disadvantages: • Fixed dose not related to pharmacodynamic variability • Errors may be fatal • Expensive fail-safe equipment required • Close monitoring of the patient is important to detect respiratory depression or over-sedation
Patient-controlled analgesia (PCA) • Intravenous PCA is now a standard method of providing postoperative analgesia in many hospital worldwide • PCA can give high-quality analgesia but can fail if not applied appropriately • PCA can be used for most surgery where moderate to severe postoperatively pain is expected
With PCA the patient determines the rate of i.v. administration of the drug thereby providing feedback control. • PCA equipment comprises an accurate source of infusion, coupled to an i.v. cannula and controlled by patient-machine interface device. Safety features are incorporated to limit the preset dose, the number of doses which may be administered and the lock out period between doses. The drug that has been most commonly used with PCA is morphine
Advantages: • Dose matches patient’s requirements and therefore compensates for pharmacodynamic variability • Doses given are small and therefore fluctuations in plasma concentrations are reduced • Reduces nurses’ workload • painless
Disadvantages: • Technical errors may be fatal • Expensive equipment • Requires ability to cooperate and understand
Epidural • Its superior to i.v. PCA for the management of pain following major abdominal surgery and lower limb amputation • Its safe to use at ward level, but this dependent on adequate monitoring and on nursing staff who have received specific training in caring for patient with epidural infusions
Used mainly for the management of pain during child birth and following major abdominal, thoracic orthopedic and vascular surgery • Opioids exhibit 10 times the potency when administered via the epidural route as opposed to the intravenous route • A combination of local anesthetic and opioid is usually administered the two drugs act synergistically resulting in superior analgesia and improved side effect profile
Contraindication to epidural: • Anticoagulation or coagulopathy • Hypovolemia • Local infection, septicemia • Lack of patient consent In addition to its analgesic effects, the utilization of epidural analgesia may decrease the incidence of DVT following orthopedic surgery and improve circulation following vascular surgery