The Effects and Dose Response of Dexamethasone on Intercostal Nerve Blocks With Bupivicaine in Post Thoracic Surgery Patients

Post-op analgesia is the most important part of early and safe patient recovery in thoracic surgery. This is for both humane and patient outcome reasons. Patient outcomes are greatly improved with optimal pain control and complications and length of stay are minimized. Most post-op thoracic complications are from decreased respiratory effort, failure to clear secretions and pulmonary infections from retained sputum with subsequent sequelae. Good post-operative analgesia not only prevents these complications but also considerably enhances early mobilization and thus, decreased hospital stay and efficient resource allocation. Early post-operative pain is also associated with late and chronic post thoracotomy pain syndromes which can be debilitating.

Pain following thoracic surgery is different to the standard surgical incision pain and is due to intercostal nerve damage, compression or traction injury to the nerve. This occurs with the incision, rib retraction, and is compounded by the on-going need for respiratory effort. The approach to managing this pain is multi-modal analgesia. The standard regimen stretches from preemptive analgesia and preoperative placement of thoracic epidurals to post-op opioid infusions. However, non-invasive pharmacology includes paracetamol, non steroidal anti inflammatory drugs (NSAIDs), mild and moderate opioids as well as anti-convulsants like pregabalin. However, opioid use has well-known side effects including central nervous system (CNS) and respiratory depression which unfortunately delay mobility and recovery. This has motivated opioid-sparing strategies.

The investigators study aims to assess whether the addition of perineural dexamethasone (a steroid) to the current practice of local anaesthetic wound catheters increases the efficacy and duration of analgesia provided.