week 13 pain

Opioids

• Tramadol inhibits noradrenaline reuptake, with minimal serotonin effect and active metabolites, which require caution in renal impairment.
• Tapentadol has minimal serotonin effect, no active metabolites, and is safer with MAOIs, SSRIs, SNRIs, and high-dose TCAs, with a lower risk of seizures.

Opioid-Induced Ventilatory Impairment (OIVI)

• Increasing sedation is a better clinical indicator of respiratory depression than oxygen saturation.
• The risk of OIVI increases with concurrent administration of sedating medications.

Regional Analgesia for Chest Wall Trauma

• Erector Spinae Plane Block (ESPB) is a regional anesthesia technique where a local anesthetic is injected between two layers of fascia.
• Serratus Anterior Plane (SAP) Block and Sub-Pectoral Plane Block are other regional anesthesia techniques.

Local Anesthetic Systemic Toxicity (LAST)

• Administering oxygen, stopping bolus, initiating medical emergency response, seizure management, and using ACLS protocols, and 20% lipid emulsion are used to manage LAST.

Epidural Infusions

• Ropivacaine 0.2% can be used for epidural infusions up to 14 ml/hr.
• Peripheral nerve block (continuous or intermittent) can be used up to 10 ml/hr.

Types of Pain

• Acute pain is recent onset, limited duration, and has an identifiable cause, with a predictable course.
• Chronic pain is persistent for more than 3 months, with a cause that is sometimes obscure or non-specific, and has an unpredictable course.
• Nociceptive pain arises from actual or threatened damage to non-neural tissue and is due to the activation of nociceptors.
• Neuropathic pain is caused by a lesion or disease of the somatosensory nervous system.
• Nociplastic pain arises from altered nociception despite no clear evidence of actual or threatened tissue damage.

Pain Management

• The Bio-Psycho Social Model of Pain considers the physical, psychological, and social aspects of pain.
• Prolonged injury response and sympathetic response can lead to various complications, including hyperglycemia, increased risk of infection, and prolonged hospital admission.

Measuring Pain

• Verbal Numerical Rating Scale, Verbal Descriptor Scale, and FACES pain scale are used to measure pain.
• Functional Activity Score (FAS) is used to assess the level of function and pain scores.

Non-Pharmacological Management

• Physical methods include rest, positioning, compression, and elevation.
• Psychological methods include explanation, reassurance, distraction, and managing expectation.

Analgesic Management

• Paracetamol reduces the need for opioids in stronger pain situations and is processed by the liver and removed by the kidneys.
• Non-selective NSAIDs (e.g., Ibuprofen) affect both COX-1 and COX-2, while selective NSAIDs (e.g., Celecoxib) mainly affect COX-2.
• Ketamine is effective in controlling severe and persistent pain by blocking NMDA receptors.
• Adjuvants, such as TCAs (e.g., Amitriptyline), Anticonvulsants (e.g., Pregabalin), and Alpha-2 Agonists (e.g., Clonidine), can be used to manage pain.

Opioids

• Morphine has active metabolites M3G and M6G, which are renally excreted, and caution is required in elderly and renal impairment patients.
• Fentanyl has no active metabolites, making it safer in renal impairment patients.
• Oxycodone is a semi-synthetic opioid derivative of thebaine, with no harmful metabolites, making it safer in renal impairment patients with dose adjustment.