Pain is a complex subjective experience comprising both physical and emotional components. The international association for the study of pain defines pain as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of damage [1].

Breast disease is commonly diagnosed with high incidence of breast cancer and leading cause of cancer related mortality among females [2].The various treatment modalities for breast diseases are surgical resection, radiotherapy, immunotherapy, chemotherapy and endocrine therapy, but surgery remains the mainstay of treatment [3].

Acute postoperative pain is common after breast surgery. However, the incidence of chronic post-operative pain is as high as 25-60% [4,5]. Inadequately treated pain, particularly acute post-operative pain is associated with physiologic changes caused by endocrine, metabolic and inflammatory response. This stress response activates the autonomic nervous system which may have adverse effects on various organ systems, which causes significant morbidity and mortality, delay in recovery, return of daily activities and the development of chronic pain [6]. 

Many options are available for the treatment of acute postoperative pain, including systemic analgesic (opioid and non-opioid) and regional (neuraxial and peripheral) analgesic technique. Regional anaesthesia with its opioid- sparing effects is most preferred as it dramatically reduces post-surgical pain and opioid- related side effects [7]. Thoracic epidural analgesia, paravertebral block (PVB), pectoralis nerve block (PEC), local infiltration with LA, intercostal nerve block, serratus plane blocks (SPB) are established techniques to provide analgesia in breast surgery, but having their own merits and demerits [8-10].        

Erector spinae plane block (ESPB) is a popular and relatively newer block first described by Forero M et al, it is simple, safe, easy to perform by ultrasound guidance (USG), not time consuming, possible immunomodulatory effect, superior patient satisfaction and minimal complications [11].

SørenstuaM et al.,conducted a study by involving 64 adult patients undergoing laparoscopic ventral hernia repair, randomly assigned to either bilateral preoperative ESPB with catheters at the level of T7 (2 × 30 ml of either 2.5 mg/ml ropivacaine or saline), with postoperative catheter top ups every 6 h for 24 h, to assess the analgesic efficacy of ESPB. They reported that no significant difference in rescue opioid consumption between ESPB and placebo groups [12].Another study by Elewa AM et al., in 2022 conducted a study to compare the analgesic efficacy, total rescue analgesic consumption and side effects of ultrasound guided ESPB and PVB for breast surgeries under general anaesthesia, involved 90 female patients and were categorized into groups I (underwent ESPB), II (underwent paravertebral block (PVB), and III (underwent general anaesthesia). They reported that both ESPB and PVB provide better postoperativeanalgesia with lesser rescue analgesic consumption compared to general anaesthesia alone. This study did not observe any significant adverse effects [13].

Similarly, Kim S et al., in 2022 conducted a study on 52 patients with American Society of Anesthesiologists physical status I, II, or III, aged 19-80 years, undergoing video-assisted thoracic surgery (VATS) divided into two groups (n=26) to compare the analgesic efficacy of erector spinae plane block (ESPB) combined with intercostal nerve block (ICNB) compared to that of thoracic paravertebral block (PVB) with ICNB. They reported that both groups provided adequate analgesic effect in VATS giving similar satisfaction scores and similar number of rescue analgesics requirement. ESPB is easier and much safer to perform requiring lesser skills and causing no adverse effects [14].

AIM

To compare the efficacy of postoperative analgesia with ultrasound guided erector spinae plane block (ESPB) and intravenous paracetamol after breast surgeries. To compare the hemodynamic changes, rescue analgesic requirement and complications in the postoperative period.

This prospective, observational comparative study was conducted in Department of Anaesthesiology, Akash Institute of Medical Sciences and Research Centre (AIMSRC), Devanahalli, Bangaluru rural, Karnataka, India. After obtaining approval from the Institutional Ethical Clearance Committee, 60 female patients aged between 18- 60 years, belonging to American Society of Anaesthesiology (ASA) grade 1 and 2 physical status, who were scheduled for breast surgeries under general anaesthesia were included in this study. Sample size was calculated by using the formula: n= Z21-α (SD)2/d2.Stratified random sampling method was followed for recruiting the study subjects.

A written informed consent of all patients was obtained before surgery. A detailed preanaesthetic evaluation including history, clinical examination, systemic examination of cardiovascular, respiratory and central nervous system, spine examination for deformity and infection was carried out one day prior to surgery.

Routine investigations like complete blood count, ESR, urine examination, random blood sugar, electrocardiogram, chest x-ray, blood urea, serum creatinine, etc. were done whenever necessary. Patients with history of drug allergy, patient refusal, coagulation disorders, neurological and congenital abnormalities of vertebral column, cardiac, respiratory, hepatic, renal disorders or insufficiency, long term use of analgesics, local infection at the site of injection, morbid obesity were excluded from the study. Patients were divided into two groups:

Group A: 30 female patients receiving ESPB with 30 ml of 0.25% bupivacaine.

Group B: 30 female patients receiving intravenous inj. paracetamol 1gram.

All patients were instructed about the visual analogue scale (VAS). Patients were informed to tell or point out the intensity of pain on the scale. All patients received T. Alprazolam 0.25mg and T. Ranitidine 150mg orally, the night before surgery as premedication. A 18G intravenous cannula was secured. Patients were kept nil per orally (NPO) for 6-8 hours prior to surgery. intravenous fluid was started with crystalloid solution.

On the day of surgery, in operation theatre all patients were monitored with baseline vitals like heart rate, non-invasive blood pressure, pulse oximetry, ECG and capnography. Patients were preoxygenated with 100% oxygen for 3 minutes, premedicated with Inj. Glycopyrrolate 0.001 mg/kg intravenously and Inj. Midazolam. Before inducing all the patients received Inj. Butorphanol 2mg and Inj. Xylocard 1-2 mg/kg intravenously. Patients were induced with Inj. Propofol (1-2 mg/kg) followed by Inj.Vecuronium (0.1 mg/kg) to facilitate tracheal intubation. Anaesthesia was maintained with isoflurane, oxygen and nitrous oxide/air with controlled ventilation. Continuous neuromuscular blockade was maintained with Inj.Vecuronium. Patients were monitored intra-operatively with non-invasive blood pressure, pulse oximetry, end tidal carbon dioxide monitoring, ECG.

In Group A (ESPB group) patients, after surgery, before extubation, the patients were positioned lateral with little forward bending, T3 spinous process was identified and marked after counting down `from C7 spinous process. Ultrasound guided ESPB was performed under strict aseptic precautions. A linear array ultrasound probe of 6-13 MHz (SONOSITE M-TURBO USA) was used. Ultrasound transducer is placed in a longitudinal parasagittal orientation, about 2.5-3cms lateral to the spinous processes, allowing for visualization of adjacent transverse process (TP) in an in-plane approach.Erector spinae muscle, Rhomboidus major and trapezius muscles are identified. After correct TP identification, a 21G 10cm needle (STIMULEX) is inserted using an in-plane approach, in cranial to caudal orientation to contact the bony shadow of the TP with the tip deep to fascial plane of the erector spinae muscle. the correct location of the needle tip in confirmed by injecting 1-2 ml of normal saline (0.9%) and observing linear fluid spread lifting the erector spinae muscle off the tip of the TP. once the fascial plane is recognized, after negative aspiration, 30ml of bupivacaine 0.25% is injected and craniocaudal spread of local anaesthetic is visualized.

In Group B (Paracetamol group), after the surgery, before extubation, all the patients received inj. paracetamol 1 gram intravenously. Time of block and time of administration of paracetamol in groups A and B was noted. Patients were extubated once fully awake and adequate muscle power was regained. Then the patients were shifted to recovery room and monitoredcontinuously. Postoperative basal systolic and diastolic blood pressures, SPO2, RR, HR were noted. Pain was assessed by visual analogue scale on a scale of (1- 10). sedation scale (5-point scale: 1-awake; 2-drowsy; 3-awake; 4-difficult to arouse; 5-unresponsive) were noted. Hemodynamics, VAS, sedation score, were recorded immediate postoperative period and intervals of 1,2,6,12,24,36 and 48 hours postoperatively.If the postoperative pain score was more than 4, rescue analgesia was provided with inj. Tramadol 50mg IV.

Time for first rescue analgesia and total number of rescue analgesics required were recorded. Postoperative complications like nausea, vomiting, pneumothorax etc. were noted. Inj. Metoclopramide 0.1mg/kg IV was given if required. Patient satisfaction about analgesia was noted at the end of the study (1- unsatisfactory; 2- satisfactory; 3-good; 4- excellent). Study was terminated at the end of 48hrs.

Statistical analysis

Demographic data were analysed using descriptive statistics. Fishers exact test and chi square analysis were conducted to compare the characteristics between both the study groups. Analysis of clinical parameters were done using independent t test. VAS scores were analysed using independent t test. All the values were expressed as mean ± standard deviation (SD). A p value (p < 0.05) was considered statistically significant.

In the present study, mean age of the patients in Group A(ESPB group) was 41.03 ± 14.66 years compared to 36.86 ± 13.81 years, in Group B (Paracetamol group).The mean weight of the patients in Group A (ESPB group)was 62.06 ± 7.51 kgs compared to 59.86 ± 8.34 kgs in Group B (Paracetamol group).There were no statistically significant differences between both the groups with regards to age and weight as shown in table 1.

Table 1: Comparison of age and weight between Group A and B

In the present study, baseline heart rates are 83.7 ± 13.16 and 78.66 ± 10.78 per minute in Group A(ESPB group)and Group B (Paracetamol group) groups respectively. Heart rate at the end of first, second and sixth hours were 80.23 ± 12.02, 76.93 ± 11.99 and 74.56 ± 13.93 in Group A (ESPB group)compared to 80.66 ± 10.34, 78.06 ± 9.32 and 77.93 ± 9.7 per minute respectively in the Group B (Paracetamol group).Heart rate at the end of twelfth, twenty-fourth, thirty-sixth and forty-eighth hours were 76.60 ± 15.31, 78.20 ± 12.26, 77.43 ± 12.95 and 74.36 ± 12.74 in Group A(ESPB group)compared to 77.26 ± 9.23, 79.46 ± 7.08, 78.80 ± 6.75 and 73.26 ± 21.20 per minute respectively in Group B (Paracetamol group).There was no statistically significant difference between the two groups with regard to postoperative heart rate as depicted in table 2.

Table 2: Comparison of postoperative heart rate variation between Group A and Group B

The baseline systolic blood pressures were 124.83 ± 12.86 and 124.47 ± 23.7 mm Hg in Group A(ESPB group) and Group B (Paracetamol group) respectively.Systolic blood pressures at the end of first, second and sixth hours were 123.4± 17.02, 121.10 ± 14.75 and 121.57 ± 13.81 mm Hg in Group A (ESPB group)compared to 130.93 ± 16.64, 125.33 ± 17.43 and 120.67 ± 14.60 mmHg in Group B (Paracetamol group).Systolic blood pressures at the end of twelfth, twenty-fourth, thirty-sixth and forty-eighth hours were 127.90 ± 20.93, 126.33 ± 16.48, 121.53 ± 15.75 and 117.60 ± 12.79 mmHg in Group A (ESPB group)compared to 124.93 ± 14.30, 121.87 ± 13.06, 118.07 ± 10.77 and 122.67 ± 15.65 mmHg respectively in Group B (Paracetamol group).There was no statistically significant difference between the two groups as shown in table 3.

Table 3. Comparison of postoperative systolic blood pressure between Group A and Group B

The baseline diastolic blood pressures were 77.13 ± 6.37 and 75.26 ± 7.39 mmHg in Group A (ESPB group) and Group B (Paracetamol group) respectively. Diastolic blood pressures at the end of first, second and sixth hours were 75.70 ± 10.70, 72.93 ± 8.65 and 76.83 ± 8.21 mmHg in Group A(ESPB group)compared to 79.06 ± 8.13, 74.26 ± 9.04 and 74.60 ± 7.48 mmHg in Group B (Paracetamol group).Diastolic blood pressures at the end of twelfth, twenty-fourth, thirty-sixth and forty-eighth hours were 77.16 ± 9.04, 75.33 ± 9.08, 70.86 ±10.66 and 72.40 ±10.89 mmHg in Group A (ESPB group)compared to 74.33 ± 10.14, 75.13 ± 8.26, 72.53 ± 7.98 and 71.46 ± 8.78 mmHg respectively in Group B (Paracetamol group).There was no statistically significant difference between the two groups as shown in table 4.

Table 4. Comparison of postoperative diastolic blood pressure between Group A and Group B

The baseline respiratory rates were 18.26 ± 2.86 and 19.79 ± 2.48 per minute in Group A (ESPB group)and Group B (Paracetamol group) respectively. Respiratory rates at the end of first, second and sixth hours were 18.83 ± 3.50, 20.46 ± 2.72 and 20.16 ± 2.45compared to 19.20 ± 2.94, 20.24 ± 2.18 and 20.62 ± 1.71 per minute respectively in Group A (ESPB group)and Group B (Paracetamol group).  Respiratory rates at the end of twelfth, twenty-fourth, thirty-sixth and forty-eighth hours were 20.30 ± 1.96, 20.53 ± 2.23, 20.63 ± 1.86 and 20.86 ± 21.87 compared to 19.62 ± 1.39, 20.06 ± 1.73, 20.62 ± 1.37 and 20.48 ± 1.45 per minute respectively in Group A (ESPB group)and Group B (Paracetamol group). There was no statistically significant difference between the two groups as in shown in 5.

Table 5. Comparison of postoperative respiratory rate between Group A and Group B

The baseline SPO2 and at the end of first hour were 99.73 ± 0.78 and 98.10 ± 1.32 in Group A (ESPB group)compared to 100 and 98.03 ± 1.03 % in Group B (Paracetamol group).SPO2 at the end of second and sixth hour were 97.66 ± 1.66 and 97.33 ±1.98% in Group A (ESPB group)compared to 97.66 ±1.66 and 96.33 ± 1.44 % in the Group B (Paracetamol group), which was statistically significant (p value < 0.05).SPO2 at the end of twelfth, twenty-fourth, thirty-sixth and forty-eighth hours in Group A (ESPB group)were 96.86 ±1.61, 96.73 ±1.50, 97.00 ± 1.14 and 97.50 ± 1.38 % compared to 96.73 ± 1.22, 96.13 ± 0.97, 96.63 ± 1.18 and 97.13 ± 1.14 % in Group B (Paracetamol group).Analysis of SPO2 % variation among both groups revealed statistically significant differences at end of second hour and sixth hour postoperatively with p <0.05 as shown in Table 6.

Table 6. Comparison of postoperative oxygen saturation (SPO₂) between Group A and Group B

                     *Statistically significant

The baseline visual analogue scale score was 0 in both groups. Visual analogue scale scores at the end of first, second and sixth hour were 0, 1.16 ± 1.23 and 2.56 ± 1.27 respectively in Group A(ESPB group)compared to 1.13 ± 1.27, 2.33 ± 1.29 and 3.66 ± 1.02 respectively in Group B (Paracetamol group), which was statistically significant (P<0.05).Visual analogue scale scores at the end of twelfth, twenty-fourth, thirty-sixth and forty-eighth hour were 3.36± 0.85, 3.36 ± 0.71, 3.13± 0.86 and 2.53 ± 0.86 respectively in Group A (ESPB group)compared to 3.76± 1.07, 3.73 ± 0.98, 3.26± 0.52 and 2.75 ± 0.66 in Group B (Paracetamol group) respectively as depicted in Table 7.

Table 7. Comparison of postoperative visual analogue scale (VAS) scores between Group A and Group B

                     *Statistically significant

The time for first rescue analgesic demand in Group A (ESPB group)was at 9 hours 30 mins ± 6 hours 30 mins compared to 7 hours 50 mins ± 2 hours in Group B (Paracetamol group). The mean difference in time at which rescue analgesia was administered showed no statistically significant difference between two groups.

A higher proportion of patients in Group A (ESPB group) did not require rescue analgesia compared to Group B (Paracetamol group). Specifically, 20 % of patients in Group A (ESPB group)did not require rescue analgesia compared to 73.4% of patients in Group B (Paracetamol group) required more than four rescue analgesics (p < 0.05).

Table 8. Comparison of total number of rescue analgesics among group A and Group B

              *Statistically significant

The baseline sedation score in Group A (ESPB group) was 2.50 ± 0.50 compared to 2.96 ± 0.41 in Group B (Paracetamol group) respectively. The sedation score in Group A(ESPB group)during 1^sthour was 1.56 ±0.50 compared to Group B (Paracetamol group) 1.96 ±0.18 respectively. There was slight increase in sedation score at baseline and 1^sthour in Group B (Paracetamol group) compared to Group A(ESPB group)which was significant (p=0.00), as depicted in Table 9.

Table 9. Comparison of postoperative sedation score among Group A and Group B

                      *Statistically significant

In Group A(ESPB group), reported complications were shoulderpain in 2, fever in 2 and back pain in 1 whereas in Group B (Paracetamol group), shoulder pain in 2, and fever in 1 patient, which were not significant. Patient satisfaction was higher in Group A (ESPB group) [excellent: 24 patients (80%), good: 6 patients (20%)], compared to paracetamol group [excellent: 2patients (6.7%), good: 26 patients (86.7%), satisfactory: 2 patients (6.7%)] which was statistically significant (p= 0.00, Х²=33.11).

Effective pain control is a major concern in the postoperative management after major surgeries. Pain at injection site, patient’s apprehensiveness, procedural complications like hypotension, unpredicted bilateral block, inadequate block by sparing certain nerves, pneumothorax, hinderance of surgical site, vascular complications, technical difficulties etc. can be avoided by an effective novel ultrasound guided regional technique like ESPB, compared to thoracic epidural, thoracic

paravertebral block, pectoral nerve blocks (PEC 1 and 2), serratus anterior plane block, intercostal nerve blocks in breast surgeries [15-17].

Ultrasound-Guided Erector Spinae Plane Block (USG-ESPB) is an excellent regional anaesthesia technique on the horizon. It has wide applications in pain relief ranging from providing postoperative pain relief in breast surgeries. It offers the advantages of simplicity, safety, easy landmark identification, superficiallocation, and a position distant from the pleura and peri-medullary area, making it highly effective in preventing postoperative neuropathic pain [18,19].

Various drugs like opioids, non-steroidal anti-inflammatory drugs (NSAID), selective cyclooxygenase (COX-2) inhibitors and metamizole (dipyrone) are used for post-operative analgesia in breast surgeries. However, intravenous paracetamol seems to be more effective in the treatment of postoperative pain, because of its opioid sparing effect, less PONV, respiratory depression, gastrointestinal, haematological and renal side effects [20,21].

In support of our study findings, Abdella AMMR  et al., in 2022 conducted a study to evaluate the analgesic efficacy and spread of variable volumes of local anesthetics (LA) in Erector spinae plane block (ESPB) on sixty patients aged between 18 -50 years with an ASA I‑II and scheduled for breast cancer surgery, divided into 3 groups of 20 each to receive either ESPB with 20 ml 0.25% bupivacaine (Standard volume ESPB), or with 40 ml 0.125% bupivacaine (high volume ESPB), or no ESPB (GA only). Preoperative ESPB can attenuate both postoperative agitation and sedation. Doubling the volume in surgeries requiring multiple dermatomes enhances the craniocaudal spread of LA.However, larger volume has no effect on analgesic efficacy or patient satisfaction [22].

Similarly, Sujin Kimet al., in 2022conducted a study on 52 patients with ASA - I, II, or III, aged 19–80 years, undergoing video-assisted thoracic surgery (VATS) divided into two groups (n=26) to compare analgesic efficacy of ESPB combined with intercostal nerve block (ICNB) compared to that of thoracic paravertebral block (PVB) with ICNB. They reported that both groups provided adequate analgesic effect in VATS giving similar satisfaction scores and similar number of rescue analgesics requirement. ESPB is easier and much safer to perform and causing no adverse effects [14].

Islam Abd Elfadelet al., in 2022 conducted a study on 54 patients aged ≤65 years belonging to ASA - II to III who are scheduled for breast conserving cancer surgery were divided into two groups, Group B and Group C of 27 patients each. Group B patients received general anesthesia with ESPB and Group C patients received general anesthesia with multimodal intravenous analgesia using morphine 5 mg, paracetamol 1 gm, and diclofenac 75 mg. They reported that ultrasound-guided ESPB performed at level of T5 with bupivacaine 0.25% in a dose of 1 mg/kg reduced rescue analgesic requirement at 24 hours postoperatively, lower VAS score and improved hemodynamic parameters in the first 8 hours postoperatively [23].

Wei-Teng Weng et al., in 2021 conducted a meta-analysis with 495 cases in 8 randomized controlled trials. They reported that ESPB is superior to systemic analgesics and can be considered as an alternative to PVB with similar analgesia [24].

Suresh Seelamet al., in 2020 conducted a study on 100 patients divided into two groups. Group A (n=50) received US guided ESPB with 30 ml of 0.25% of bupivacaine. Group B (n=50) received no block. They reported thatpostoperative rescue analgesic consumption was significantly less in Group A compared to Group B, with no difference in complications and PONV reduction in either groups [25].

In a study done by Thiagarajanet al., mean pain score was lower in ESPB group (Inj. Bupivacaine 0.25%) compared to intravenous analgesia group (Inj. Paracetamol 15 mg/ kg, injection diclofenac 1 mg/kg) and statistically significant at 2 hour during best surgeries under GA[26]. In our study also there was a significant reduction in VAS score in ESPB Group compared to paracetamol group at first 6 hours.

Another study by Hassan ElHawaryet al. in 2019 conducted a systematic review including 6 randomized controlled trials and concluded that ESPB can decrease postoperative pain and opioid consumption when used as part of multimodal pain analgesia for patients undergoing breast surgery with lesser complications [27].

In another study Singh et.al, also found the ESPB group (Injection bupivacaine 0.5% 20 ml at T5 level) had lower VAS score compared to control group and concluded that VAS score and rescue analgesic (injection morphine) was significantly lower in patients receiving USG guided ESPB [28].

Jain K et al., in 2018 reported a series of six cases, which include postoperative pain management in breast, thoracic, and abdominal surgeries along with management of two chronic pain cases to illustrate the potential uses of continuous and single-shot ESP block and the study showed that ESPB can provide good acute postoperative pain relief in various surgeries and also has a role in reducing chronic neuropathic pain [29].

In our study, total number of rescue analgesic consumed was consistently higher in paracetamol group (73.4%) compared to ESPB group (20%). And also, the paracetamol group needed more than four rescue analgesics during the study hours, compared to ESPB group, concluding ESPB provides better analgesia than paracetamol group.

In a study done by Puthenveettil et al, total number of rescue analgesic consumption (Inj. Tramadol) was significantly different between ultrasound guided ESPB group compared to postoperative site local Infiltration group (23.3% vs 70%), concluded ESPB provides better pain relief than other group [30].

Gurkanet.al., reported that there was no difference in incidence of complications like PONV etc. between the study groups [31].Hui-fang Liet al. in 2020 conducted a meta-analysis on six randomized controlled trials to study the analgesic effects of ESPB in patients undergoing breast surgeries. They reported that ESPB can significantly reduce postoperative pain and rescue analgesic requirement postoperatively. There was no significant reduction in the incidence of postoperative nausea and vomiting and no adverse effects were reported [32].

The patient satisfaction with analgesics was significantly better with USG-ESPB than paracetamol group. B M et al., in 2023 conducted a study on 66 patients of age 18- 80 years, belonging to ASA 1,2  and were divided into 2 groups M and N consisting of 33 patients each. Patients in Group M received multimodal analgesia in the form of Erector Spinae Plane Block + General Anesthesia + Opioid-Free Analgesic Mixture (1 mcg/cc dexmedetomidine + 1 mg/cc ketamine + 100 mg/cc magnesium sulfate prepared in a 20 ml syringe). Group N received Erector Spinae Plane Block + General Anesthesia + 20ml Of Normal Saline Infusion. They reported that intravenous administration of OFA mixture as an adjunct to ESPB performed at T4 level using 25 ml of 0.25% bupivacaine combined with 8 mg dexamethasone reduces postoperative pain scores, prolongs the duration of postoperative analgesia as well as reduces the requirement of rescue analgesics in the postoperative period, and provides better patient satisfaction and more stable intraoperative hemodynamics in patients undergoing breast cancer surgery under general anesthesia [33].

Limitations

The limitations of our study are blinding of study and allocation concealment was not done. In our study all the patients were ASA I and II, and we did not evaluate patients with multiple co-morbidities.

This study may conclude that the pain relief in ESPB group was significantly better than paracetamol group. The total consumption of rescue analgesic was significantly higher in paracetamol group compared to ESPB group. The sedation score was slightly increased in paracetamol group compared to ESPB group during first one hour. The patient satisfaction was significantly better with ESPB group, suggesting for postoperative analgesia, ultrasound guided erector spinae plane block is better than intravenous paracetamol after breast surgery. Further studies with large sample size are recommended.

Conflict of interest: Nil

Funding: Nil

Acknowledgements: We would like to thank the authorities of Akash Institute of Medical Sciences and Research Centre, Devanahalli, Bengaluru, Karnataka, India.

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