This study will target patients with gastrointestinal (GI) malignancy who present to any of 4 Penn Medicine emergency departments (EDs) with intractable abdominal pain. We will offer eligible patients an erector spinae plane block (ESPB), a regional anesthesia technique which is already offered to such patients in the ED at the University of Pennsylvania Healthy System (UPHS), for their intractable abdominal pain. We will compare the outcomes of this prospective cohort of patients to a matched historical control of patients with GI malignancy who were treated in the ED during the same time period as recruitment, but who were not recruited to partake in the study and who were managed with standard of care. Opioid consumption as measured by total milligram morphine equivalents (MMEs) over a 24-hour period and hospital length of stay (LOS) will be compared between cohorts. Additionally, for the ESPB cohort, pain level pre/post ESPB, and functionality and satisfaction with pain management at 24 hours will also be examined.
Primary objective: To determine whether patients with GI malignancy receiving an ESPB for intractable abdominal pain consume less opioids (measured in MMEs) in a 24-hour period compared to standard of care analgesia.
Secondary objectives:
To determine whether patients who receive an ESPB have shorter hospital LOS compared to standard of care analgesia.
Within the cohort receiving the ESPB, to determine whether there was a change in pain level as measured by the numeric rating scale (NRS) pre/post block.
Exploratory: Within cohort receiving the ESPB, to determine level of patient satisfaction and functionality as measured by the Revised American Pain Society Patient Outcome Questionnaire (APS-POQ-R)
Patients with a GI malignancy presenting with intractable abdominal pain. To any of 4 EDs, (1) Hospital of the University of Pennsylvania (HUP), (2) Penn Presbyterian Medical Center (PPMC), (3) Pennsylvania Hospital (PAH), and (4) HUP Cedar (Cedar) Exclusion criteria: pregnant, incarcerated, admissions for serial abdominal examinations, small bowel obstruction, sepsis, altered mental status, hemodynamic instability.
Participants will receive an ESPB, a nerve block performed by injecting anesthetic between a single spinal transverse process and the erector spinae muscle complex (Forero et al). Anesthetic reaches the dorsal nerve root ganglia but also diffuses anteriorly to the paravertebral space which contains the thoracic sympathetic ganglia (Chin et al). Visceral afferent fibers transmit pain signals arising from the stomach to midway through the sigmoid colon utilizing the same anatomical conduit as sympathetic efferent fibers (Moore et al). While physically associated, they travel in the reverse direction of the sympathetic efferents and are functionally distinct. From the abdominal viscera to spinal cord, visceral afferents transmit pain signals first through the peri-aortic autonomic plexuses and prevertebral ganglia, then along the splanchnic nerves to reach the sympathetic trunk, where they travel via the white rami communicantes to reach the spinal nerves of T5 to L2, before finally being conducted centrally. Thus, anesthetizing the thoracolumbar spinal nerves and sympathetic chain, via an ESPB performed between the levels of T5 and L2, should block abdominal visceral pain signaling, and may provide significant analgesia for patients with abdominal pain from GI malignancy.
