Background: Spinal anaesthesia consists of inserting a spinal needle into the subarachnoid space and, when a free flow of cerebrospinal fluid (CSF) is obtained, injection of a solution of local anaesthetic directly into the CSF. In SA Patients is used for subumbilical surgeries but still there is a concern about its safety & feasibility. Objective: To assess low dose spinal anaesthesia and its safety in cardiac compromised and highly risk patients. Materials and Methods: In this prospective study was conducted in the Dept. of Anaesthesia, Ibrahim Cardiac Hospital, Dhaka, Bangladesh from September 2021 to January 2022. Forty patients of aged 20-80 years were included undergoing. All patients age group American society of anesthesiology grade III-IV, with any cardiorespiratory abnormility scheduled for elective infraumbilical surgeries like ATK amputation, BTK amputation, LASER surgeries & other Vascular surgeries ete. Patients with known contraindication to spinal anaesthesia were excluded. Relevant investigation was done e.g. haemoglobin, complete blood count, kidney function test etc. Special investigation like chest x-ray, coagulation profile only Echo, ETT if needed. On the day of surgery in preoperative room vital parameters (Heart Rate, Respiration, Blood Pressure, liver function test, Spo2) were noted & CV line and arterial line can be done if needed. Demographic data, vital parameters, sensory –motor block characteristics & complications were noted. Results: In our study mean and standard deviation of mean age is 43.76±10.33 and Mean Weight (Kg) 69.7±7.4. Out of the 40 cases, 27 were males whereas the remaining 13 were females. Forty patients of different age group, sex and weight of ASA III and IV categories were included in this study, out of which 10 patients were in age group 18-25 years (5%), 10 patients were in age group 41-50 years (25%) and 17 patients were in age group 51-60 years (42%). In this study indication high perception LASER surgery........