Prophylactic Perioperative Fluid Infusion Strategy During Splanchnic Nerve Neurolysis to Prevent Systemic Hypotension: A Case Series of 70 Patients With Cancer.

Background: When performing splanchnic nerve neurolysis (SNN), systemic hypotension may occur due to upper abdominal sympathetic blockade; therefore, appropriate periprocedural fluid resuscitation is crucial.

Objectives: The aims of this retrospective observational study were: 1) to validate the efficacy and safety of our prophylactic periprocedural fluid resuscitation in order to prevent systemic hypotension post-SNN, and 2) to explore the indicators that predict the need for additional fluid administration post-SNN.

Study design: This was a retrospective observational study using medical records from electronic medical charts.

Setting: All patients who received SNN in the Division of Palliative Medicine of Shizuoka Cancer Center from April 2016 through November 2022 in order to relieve pain caused by upper abdominal cancer and/or abdominal paraaortic lymph node swelling, had their electronic medical charts reviewed. Pancreatic cancer (n = 41) was the primary pain origin.

Methods: SNN was performed with the patient prone. Under fluoroscopic guidance a transdiscal approach using a 22G nerve block needle was utilized. The patients maintained their prone position for an hour postprocedure and rested in bed until the following morning. Urine output and blood pressure were measured every postprocedure 4 hours. One thousand mL of dextran 40 solution and 1,000 mL of lactated Ringer's solution were administered as basic fluids during the perioperative 24 hours; additional lactated Ringer's solution was adminstered when oliguria and/or hypotension was observed post block. We recorded patient background data, including the primary malignancy site, clinical classification of pain mechanism, performance status (Eastern Cooperative Oncology Group), presence of diabetes mellitus, hypertension, serum albumin level, hemoglobin level, hematocrit level, C-reactive protein level, estimated glomerular filtration rate, glomerular filtration ratio, presence of celiac plexus invasion and/or peritoneal dissemination,  neurolytic agent dose, postblock pyrexia, and survival time post-SNN.

Results: Seventy cases (68 patients, 62.5 ± 12.0 years, 32 men and 36 women, duplicated in 2) were analyzed. The volume of anhydrous ethanol administered as the neurolytic agent was 16.8 ± 2.6 mL. Fourteen patients (21%) received 250 - 1,250 mL of lactated Ringer's solution as additional postprocedure fluid due to oliguria. No systemic hypotension was observed at pre- or  postprocedure. No clinical signs of excessive fluid, such as pleural effusion, ascites, edema, and/or dyspnea, was observed. The only indicator to predict the need for additional fluid administration was the dose of neurolytic agent (anhydrous ethanol).

Limitations: The limitations of this study include, firstly, its single-center retrospective observational design. Secondly, although the number of patients in this study was relatively large for a single-center clinical report of SNN, it would probably be more effective to have additional cases in a future prospective study, which would contribute to establishing a more precise method of fluid resuscitation in order to avoid systemic hypotension induced by SNN.

Conclusion: Our prophylactic perioperative fluid resuscitation for treating systemic hypotension post-SNN is sufficient and safe.