Comparison of combined spinal - general anaesthesia versus general anesthesia alone for intraoperative hemodynamic changes and postoperative analgesia in robotic- assisted laparoscopic hernia repair surgeries - randomised controlled trial

• After proper optimization of the patient, the patient’s vitals, airway and oral cavity are again examined on the day of the surgery. Nil by mouth status of the patient is confirmed on the day of surgery.
• Confirmation about the operation site taken from the surgeons.
• Written informed consent is taken from the patient and patient’s relatives after explaining about the procedure and about the study.
• Patient is taken inside the operation theater and multiple parameters monitors measuring pulse, blood pressure, mean arterial pressure, oxygen saturation, respiratory rate, end tidal carbon dioxide and ECG tracing are attached. Intravenous access is secured, preferably with a wide bore needle - 18 G/ 20 G, preferably on the non operating side. Extension lines are attached to the wide bore intracath for easier intravenous access.
• Patients were premedicated with injection pantoprazole 40mg iv, injection ondansetron 4mg iv given slowly over five minutes and antibiotic as per the preference of the surgeon is administered.
• Patients were preloaded with lactated Ringer solution 15 mL/kg.
• For patients falling under Group A of the study, spinal anesthesia was administered before general anesthesia. Under all aseptic precautions subarachnoid block is given in third and fourth lumbar intervertebral space in sitting position using 25G Quincke spinal needle, with 0.5 % hyperbaric bupivacaine 10 mg and buprenorphine 150 microgram after confirming positive aspirate of cerebrospinal fluid and a free flow of cerebrospinal fluid.  Patient is immediately given a supine position and the operating table was adjusted in order to achieve a sensory level blockade of T6. Time of spinal injection is considered as time 0.
• Onset of spinal anaesthesia is checked. Sensory blockade was checked with pin prick test and motor blockade was checked with modified Bromage scale. Maximum sensory blockade and motor blockade was noted.  After 20 minutes or time for maximal spinal action- T6 sensory blockade, whichever occurred earlier, general anaesthesia was induced.
• Both the patient groups A and B were preoxygenated with 100% Inspired Oxygen [FiO2] for three minutes on closed circuit with spontaneous ventilation. Patient sedated with  injection Midazolam (0.03 mg/kg) IV, injection Fentanyl (2 µg/kg) IV. Patients  induced with injection Propofol IV titrated to the loss of verbal response and abolition of eyelash reflex and the amount of drug administered will be noted and injection Vecuronium as a muscle relaxant will be administered in the dose of 0.1 mg/kg IV to facilitate intubation. Patient is oxygenated for 3 minutes after injection of the relaxant.
• Patients will be intubated with appropriate size endotracheal tube using conventional laryngoscopy with appropriate sized Macintosh laryngoscope with blade 3 or blade 4. The pilot balloon is inflated and air entry is checked on bilateral lung fields using a stethoscope.
• Patient is maintained on Oxygen, nitrous oxide and isoflurane.
• Isoflurane was used in the lowest possible concentration to keep MAP and HR within 20% of baseline and under deep plain of sedation. Intermittent boluses of Inj vecuronium 1mg was given to maintain the plane of anaesthesia.
• End tidal CO2 was maintained at 35 - 45 mm Hg and airway peak pressure maintained at <40 cm H2O . Appropriate interventions in ventilation were made if there was an increase in both the parameters.
• The time was noted when pneumoperitoneum using carbon dioxide gas was created and the pressure was kept between 12 and 15 mm Hg for all patients. The vitals during creation of pneumoperitoneum - heart rate, systolic blood pressure, diastolic blood pressure and mean arterial pressure were documented.
• When the oxygen saturation dropped below 92% nitrous oxide was switched off and then the patient was maintained with 100% oxygen. Appropriate intraoperative interventions were done if there was a 20% change in the baseline vital parameters.
• If the blood pressure dropped to more than 20 % of the baseline levels then 100mL fluid boluses of either Ringer Lactate solution or Normal saline solution were given, if the blood pressure still not responded then Inj Mephenterine 6mg IV stat dose was given.  If the heart rate is less than 20% of baseline then patient will be treated with Inj Atropine 0.3 mg iv and repeated if required.
• If the heart rate and blood pressure increased to more than 20% of the baseline levels,  Inj. Metoprolol 0.1 mg/kg was given in titrated doses to maintain MAP. The total dose of metoprolol required intraoperatively during the surgery was recorded.
• Alpha-2 agonists were avoided due to their additional sedative properties.
• Monitoring was carried out by the attending anesthesiologist blinded to the technique. Intraoperative monitoring was done every 3 minutes after injection of drug intrathecally for the first 20 minutes and every 15 minutes after induction by general anaesthesia. Parameters measured are systolic blood pressure, diastolic blood pressure, mean arterial pressure, heart rate, and total dose of metoprolol required.
• After adequate spontaneous attempts at respiration are seen, the oropharynx was gently suctioned using soft suction catheter and reversal of the neuromuscular blockade was done with neostigmine 0.05mg/kg IV and glycopyrrolate 8 mcg/kg IV. After regaining complete consciousness, the patient was extubated.
• The time taken from closure of surgical incision till extubation is complete is noted as Recovery time.
• Sensory and motor blockade was checked immediately after extubation and documented.
• Surgeons were asked to grade the operative field on the basis of bowel contractility and need for head low. It was quantified by Numeric Rating Scale from 1 - 10 with 1 meaning poor operative field and the need for maximum head low and 10 meaning best operative field with minimum head low.

POST OPERATIVE:

• Patients were shifted to the post operative room and observed for 2 hours for regression of spinal anaesthesia. Level of sensory blockade was noted. After shifting the patients to the respective ward, they were observed for 24 hours for post operative requirement of analgesia and respiratory depression.
• Post operative analgesia duration was defined as the time after completion of surgery to appearance of pain Visual Analog Scale score [VAS score]  >4.  Quality of analgesia was assessed using VAS on a 0-10 scale, where a score of 0 represents no pain and 10 was the worst pain imaginable.
• Injection Diclofenac 75 mg intravenously was administered as rescue analgesia when the patient complained of pain or when the VAS score was >4. If Injection Diclofenac was ineffective in providing analgesia then Injection Fentanyl 25 mcg was given as a bolus dose. The time taken to administer the first rescue analgesic and the total use of rescue analgesia in 24 hours was noted. Various side effects like the incidence of nausea-vomiting, pruritus, and shivering were recorded.