DRY TAP IN SPINAL ANAESTHESIA…IS TOLVAPTAN THE CULPRIT?

Abstract

For Lower limb surgeries in elderly patients, regional anaesthesia is generally favoured due to its stable cardiovascular profile and smoother postoperative recovery. However, factors such as medication effects and age-related spinal changes can complicate its administration. We report the case of an 80-year-old female with hypertension, prior stroke, and chronic hyponatraemia on tolvaptan, who presented with a left femur fracture for proximal femoral nailing. Multiple spinal attempts at different interspaces using 23- and 25-gauge Quincke needles produced the characteristic “give-way” sensation but no cerebrospinal fluid return, resulting in a dry tap. The procedure was subsequently converted to general anaesthesia. Tolvaptan, a vasopressin receptor antagonist causing aquaresis, may have contributed to reduced CSF volume and dehydration. This case highlights the importance of recognising drug-related causes of failed spinal anaesthesia. Detailed preoperative assessment, adequate hydration, and preparedness for alternative anaesthetic techniques are essential for safe management in high-risk elderly patients.