Ultrasound Guided, Continuous Erector Spinae Plane (ESP) Block in Minimally Invasive Thoracic Surgery: Comparing Programmed Intermittent Bolus (PIB) vs Continuous Infusion on Quality of Recovery and Postoperative Respiratory Function

Minimally invasive thoracic surgery (MITS) has been shown to reduce postoperative pain, reduce tissue trauma and contribute to better recovery as compared to open thoracotomy. However, it still causes significant acute post-operative pain. Our Mater research group has shown that fascial plane blocks such as the Erector Spinae Plane block (ESP) contribute to post-operative analgesia after MITS. Case reports have described the improved quality of analgesia following ESP using programmed intermittent boluses (PIB) instead of continuous infusion. It is hypothesised that larger, repeated bolus doses provide superior analgesia, possibly as a result of improved spread of the local anaesthetic. Evidence for improved spread of local anaesthetic may be found in one study which demonstrated that PIB increased the number of affected dermatomal levels compared to continuous infusions for continuous paravertebral blocks. Similarly, with regard to labour epidural analgesia, PIB provides better analgesia compared with continuous infusion.

Because fascial plane blocks, such as ESP, rely on the spread of local anaesthetic on an interfacial plane, automated boluses may be particularly useful for this group of blocks. However, until recently, ambulatory pumps capable of providing automated boluses in addition to patient-controlled boluses were not widely available. To the best of our knowledge, there are no randomised controlled trials comparing continuous infusion versus intermittent bolus strategies for Erector Spinae Plane Block for MITS in terms of patient-centered outcomes such as quality of recovery.