The Journal of the Arkansas Medical Society Med Journal Sept 2019 FInal 2 | Page 16

CASE STUDY Determination of Spread of Injectate After Ultrasound-Guided Pecto-Intercostal Fascial Plane Block: A Cadaveric Study Dale Barefoot, MD 2 ; Michael Fiedorek, MD 2 ; Kevin D. Phelan, PhD 3 ; Gregory Mehaffey, MD 1 ; Mark Stevens, MD 2 ; Charles Napolitano, MD, PhD 2 1 Department of Anesthesiology, College of Medicine, UAMS 2 Department of Anesthesiology, College of Medicine, UAMS 3 Neurobiology and Developmental Sciences, College of Medicine, UAMS ABSTRACT O bjectives: The goal of this observational study was to establish the expected spread of local anesthetic throughout the pecto-intercostal fascial (PIF) plane using ultrasound-guided injection of methylene blue dye. Five lightly embalmed cadavers were injected bilaterally within the PIF plane under ultrasound guidance, and the chest walls were then dissected to determine injectate spread. Results: Ultrasound-guided injection of the PIF plane achieved a spread throughout the plane entirely. Conclusion: Ultrasound-guided injection of the PIF plane reliably involves the anterior cutaneous branch of the intercostal nerves that innervate the sternum. INTRODUCTION Most pain-management techniques for anterior-chest-wall pain following chest-wall trauma, sternotomy, thoracic drainage tube placement, and mastectomy have involved the judicious use of opiate medications in the belief that they are associated with optimal hemodynamic stability and pain control. However, large amounts of intravenous opioids can delay extubation and have multiple side effects including respiratory depression, sedation, urinary retention, constipation, and puritus. 1 The pecto-intercostal fascial plane block (PIFB) is an innovative, local technique that presents an alternative method of providing analgesia for rib-cage and sternal pain. 2 Patients in pain will have prolonged immobilization, insufficient respiratory function, difficulty coughing and a subsequent longer period of mechanical ventilation, longer ICU stays, and longer overall hospital stays. 2 Inadequate analgesia and uninhibited perioperative surgical-stress responses also have the potential to initiate pathophysiologic changes in all major organ systems leading to hemodynamic instability, cardiac overload, increased oxygen consumption, and increased risk of myocardial ischemia. 3 Different techniques, including blind parasternal injection and large-volume local anesthetic infiltration of the sternotomy wound, have previously been described as a way to decrease opioid requirements, provide early postoperative analgesia, and facilitate early extubation. 4,5 In one study, the use of ultrasound to guide local anesthetic placement in the PIF plane was described as a way to assist in the extubation of critically ill patients who were difficult to wean from ventilators. 6,7 It is believed that the utilization of the PIFB to anesthetize the anterior cutaneous and lateral branches of intercostal nerves will ultimately reduce opiate consumption and the complications associated with their use. There is no anatomical description of local anesthetic spread for the PIFB in the literature. The goal of this study is to establish the expected spread of local anesthetic throughout the PIF plane and the nerve involvement using an ultrasound-guided injection of dye into the hemi-chest walls of lightly embalmed cadavers. Figure 1: Spread of injectate within the PIFB plane between the pectoralis major muscle (PMM) and the external intercostal muscle (EIM). The needle is indicated by arrows. 64 • THE JOURNAL OF THE ARKANSAS MEDICAL SOCIETY VOLUME 116