A sealed envelope randomization will be employed to allocate patients  into two groups  either  to  receive  ESP  block with local anaesthetic drug  bupivacaine and patient receiving ESP block with normal saline.

Patient will be premedicated with intravenous inj. glycopyrrolate (5mcg/kg), inj. Midazolam (0.05mg/kg), inj. Fentanyl (2mcg/kg). Induction will be achieved by inj.  Propofol (2mg/kg) and intubation will be facilitated with inj. vecuronium (0.08mg/kg). Anaesthesia will be maintained with 50% of nitrous oxide in oxygen and isoflurane along with inj. vecuronium(0.02mg/kg) maintenance dose as required.  All hemodynamics parameter will be recorded at every 15 min interval until patient will be shifted from the operating room.

Erector spinae plane  block  will  be performed  after completion of pcnl surgery  under  ultrasound  guidance  using  a  linear  transducer.

  Group E (n=30):  group E will receive  Erector  Spinae  Plane Block with  Local Anaesthetic (LA) mixture  10 ml  of 0.5% Bupivacaine, 5 ml of  Lignocaine 2%, 1 ml (50mcg) of fentanyl, 4 ml of  NS  to  make  a  mixture  of  20 ml,  which  will be  injected on the side of surgery.

Group C (n=30):  group C will receive Erector  Spinae  Plane Block  with 20 ml of   normal saline   injected  on the side of surgery.

In Group E patients, Erector  Spinae  Plane (ESP) block  will  be  performed  in  prone position  after  ensuring  skin  asepsis, we  place  high  frequency [5-13 MHz]  linear  ultrasound  transducer  in  sterile  sheath  3 cm lateral  to  the  T9  spinous   process to visualize  the  back  muscles: trapezius  above, rhomboid  major  in  the  middle, and erector spinae  muscle  on  the  bottom. A 23G 10-cm  Touhy  needle  will  be  inserted  using  an  in plane  superior to inferior approach  until the needle touched the Transverse Process  crossing all three muscles. A volume  of  20 ml  of  LA  mixture  will  be  injected.

 In Group C  patients, same procedure as above will be performed, but in place of drug we will inject a volume of 20 ml of  normal saline on the surgery side.  

After completion of ESP block procedure, all  the anaesthetic agent will be stopped and after the onset of spontaneous respiration, residual neuromuscular blockade will be reversed with Inj. Neostigmine (5mcg/kg) and Inj. Glycopyrrolate (10 mcg/kg)  and  extubation will  be  done . before shifting the pts to postoperative ward we will give injection paracetamol 15mg/kg body wt as analgesic to all pts.

PTs will be assessed for pain by VAS scores (ranging from 0 indicating no pain to 10 indicate extreme pain) will be recorded 30 min and 2,4,6,12,and 24 hr. postoperatively.

  When VAS Score is more then 4 we will give intravenous tramadol 100 mg (maximum up to 400 mg) as postoperative rescue analgesic. . The  amount  of  rescue  analgesia  require  in  both  groups during  first  24 h  after operation , pts satisfaction score using Likert Verbal Rating  Scale and complications if any occur  will  be  recorded.

The  hemodynamic  parameters  like  Heart rate, Systolic Blood pressure, Diastolic blood pressure , Mean arterial pressure, Saturation(spo2), Etco2 will  be  taken  after  the  block and  patients  will  be  monitered  upto  24  hrs  after  the  block.  Adverse  events  such  as  Bradycardia (HR <50 bpm  or  20%  decrease  from  the baseline  value), Hypotension (fall  in  blood  pressure  by  20%  from  the  baseline or an  absolute  MAP <60 mmHg) , Nausea,  Vomiting,  Dryness  of  mouth  or  any  other  events  during  or  within   the  procedure  will  be  noted. Bradycardia  will  be treated  with  increment  doses  of  injection  Atropine 0.3mg  and  Hypotension  will be  managed  with  a  bolus  of  IV  crystalloids  or  with  increments  of  injection Mephentermine  6 mg.