Effect of intraoperative use of Isotonic Saline, Ringer’s Lactate and a combination of both on postoperative serum sodium levels in lower limb orthopedic surgeries- A double blind randomized controlled trial

After obtaining permission from the institutional ethical committee and written informed consent from the patients, patients will be recruited in this prospective double blind randomized controlled trial. Preanaesthetic examination and preparation: Patients will undergo routine preanaesthetic examination before considering for surgery. Patients who fulfill the above-mentioned inclusion criteria will be enrolled in the trial after obtaining a written informed consent.Patients will be instructed to follow standard ASA preoperative fasting guidelines (6h for solids and non-clear liquids and 2 h for clear liquids) and premedicated with oral pantoprazole 40 mg on the previous night of surgery. On the day of surgery, we will reassess the patients in preoperative room. Confusion Assessment Method (CAM) tool will be applied to rule out confusion/ delirium in the patient. An intravenous (IV) access with a wide bore cannula will be secured and the baseline vitals like Heart rate, Blood pressure and SpO2 recorded. A Blood sample will be drawn and sent for estimation of serum sodium levels, which will be noted as baseline levels. The patients will then be randomly allotted into one of the three groups (based on a computer-generated random number table): Group IS -Patients will be administered with Isotonic saline intraoperatively and postoperatively from the time the patient is taken to the operating room (OR) till 6 hours after surgery. Group RL-We will be administered with Ringer’s lactate intraoperatively and postoperatively from the time patient is taken to the OR till 6 hours after surgery. Group IS +RL -We will be administered with Isotonic saline and Ringer’s lactate intraoperatively and postoperatively from the time patient is taken to the OR till 6 hours after surgery. Blinding process : Allotment of the patient to any group will not be known to the principal investigator. Intraoperatively, the name of the IV fluid will be concealed using a white paper by the OR anaesthesia technician. The patient will not be told to which group he/ she belongs to. This is a double-blind RCT. In the OR, IV fluids will be administered according to Holliday Segar formula  to cover fasting requirements [1] . Maintenance rate of the fluid will be administered as per the weight of the patient throughout the surgery. The patients will be administered spinal anaesthesia as per the attending anaesthesiologist. Any requirement for transfusion of any blood products will be noted. After the surgical procedure the patient is shifted to the post anaesthesia care unit (PACU) and monitored for 1 hour. IV fluid will be administered as per the trial group the patient belongs to till 6 hours post-surgery. Complaints like lethargy, confusion will be noted. At 6 hours post-operatively, the administration of IV fluid will be stopped and a blood sample will be drawn and sent to the laboratory for the estimation of Serum sodium levels. Another blood sample for Serum sodium level estimation will be drawn and sent again after 24 hours from this time-point. Post operative nausea and vomiting will be observed for 24 hours of surgery. Assessment for confusion/ delirium will be performed using CAM:

1. Immediately when the patient is shifted to PACU
2. 6 hours post-surgery in the ward (Time point B)
3. 24 hours after time-point B (time point C) in the ward The patient will be followed up till the day of discharge.