Many people list orthopaedic surgery as one of the most painful types of surgery. Due to the nature of orthopaedic surgery, which typically requires extensive muscle and skeletal tissue repair or reconstruction, intense pain is frequently experienced following the procedure. In addition, a large percentage of patients undergoing orthopaedic surgery have underlying chronic (persistent) pain that, if not well managed prior to surgery, can complicate and increase the complexity of postoperative pain management.[1-3]

An ever-increasing number of lower limb surgeries, e.g., total knee arthroplasty, arthroscopic knee surgeries, lower limb fracture fixations, and ankle and foot surgeries etc., demand better outcomes with minimal morbidity and mortality and early mobilization and discharge. The central neuraxial and regional anaesthesia and analgesia techniques significantly reduce perioperative morbidity and mortality.[4]

Four-in-one block offers blockade of four nerves namely saphenous, obturator, sciatic nerves and nerves to vastus medialis. It can provide ease and a better post operative analgesia for knee and below knee surgeries. This block is an easily administrable nerve block to achieve analgesia of the sciatic nerve distribution in supine position for knee surgeries postoperatively.[5,6] 

The main benefits that we have seen in our practice are that it is simple to perform while supine (even without the frog leg position), that there is no need for a separate injection or position change to block the sciatic nerve, that it is relatively safe in the hands of an experienced practitioner, that it is a good option for post-op analgesia in below knee surgeries, and that the distribution of the sciatic nerve is primarily blocked sensoryly.

We hypothesised that 0.125% bupivacaine with two different doses of dexmedetomidine 0.5 µg/kg and 1 µg/kg may have different effect on Hemodyanamic Variables  both Intra-operatively & Post-operatively when administered in ultrasound guided 4-in-1 block. Since this block is a relatively new block and only a couple of studies are available in literature, it would be worthwhile to compare the Hemodyanamic Variables  both Intra-operatively & Post-operatively of 4-in-1 block with bupivacaine in combination with dexmedetomidine in two doses.

Aim and Objectives

To compare the Hemodyanamic Variables both Intra-operatively & Post-operatively  in ultrasound guided 4- in -1 nerve block with Bupivacaine in Combination with Dexmedetomidine in Two Doses for knee and below knee orthopaedic surgeries.

Study Area: Department of Anaesthesiology, Dr. R.P.G.M.C. Kangra at Tanda, Himachal Pradesh.

Study Population: All consecutive patients in the age group 18-60 years including both genders scheduled for knee and below knee surgery under subarachnoid block (SAB) were enrolled for this study after obtaining written informed consent.

Study Duration: After approval by Institutional Ethics Committee(IEC), this prospective, randomized, double blinded, study was carried out over a period of 18 months including data collection, data organization, presentation, data analysis and data interpretation.

Sample Size: All patients within this duration and fulfilling our inclusion criteria were included in the study. The patients were divided into two groups -group A and group B. For each group, 50 patients were evaluated after randomization.

Inclusion Criteria

1. ASA grade Ⅰ and Ⅱ patients scheduled for knee and below knee surgery under SAB with expected duration of 2 hours were intended in the current study.

2. BMI 18.5-29.9 Kg/m².

Exclusion Criteria

1. Patient’s refusal for spinal anaesthesia or 4- in -1 block.

2. Patients with anatomical deformities.

3. Patients with coagulopathies and bleeding disorders.

4. Patients with hypersensitivity to study drugs.

5. Patients on anticoagulants.

6. Local infection at the site where needle for block is to be inserted

7. Patients with known bradyarrhythmia, heart block, significant cognitive impairment.

8. Failure of spinal anaesthesia.

Study design: It was a prospective, randomized, double-blindstudy. The patients undergoing knee and below knee surgery were randomly divided into two groups (A and B). Randomization was achieved by computer-generated random number table. The randomization group assigned was enclosed in a sealed opaque envelope to ensure concealment of allocation sequence. After shifting the patient inside operation theatre, sealed envelope was opened by anaesthesiologist not involved in the study to prepare the drug solution according to allocation. The drug solution made was then made and handed over to the team member giving the block.

Methodology: The study commenced after obtaining institutional scientific review and protocol committee, ethics committee approval and written informed patient’s consent.

The enrolled patients, after fulfilling all the inclusion and exclusion criteria, were divided into 2 groups:

Group A- received 29 ml of 0.125% bupivacaine with 0.5 µg/kg dose of dexmedetomidine (1 ml) making it to a total 30 ml solution, in USG guided 4-in-1 block.

Group B- received 29 ml of 0.125% bupivacaine with 1 µg/kg dose of dexmedetomidine (1 ml) making it to a total 30 ml solution, in USG guided 4-in-1 block.

Anaesthetic Procedure-

Pre-anaesthetic assessment was done one day prior to surgery. All patients were explained about the procedure, advantages, and risks of the procedure. The patients were educated about the 11-point Verbal Rating Scale (VRS) where 0 is no pain and 10 is worst imaginable pain. Thereafter written consent was taken and clinical details were recorded in a predesigned proforma.

All the patients were kept nil orally for 8 hours before surgery and pre-medicated with tablet alprazolam 0.25 mg and tablet ranitidine 150 mg the night before surgery and 2 hours before surgery with a sip of water. In the operation theatre, an 18-gauge intravenous (IV) cannula was secured followed by 0.9% sodium chloride (normal saline [NS]) infusion. After establishing standard anaesthesia monitoring, baseline parameters such as heart rate (HR), non-invasive blood pressure and peripheral oxygen saturation were recorded. Patients were given SAB after cleaning and draping,in sitting position using 26-gauge Quincke spinal needle at L3–L4 interspace with 3.0ml 0.5% hyperbaric bupivacaine after ensuring free flow of cerebrospinal fluid. After confirmation of adequate level (T6) the surgeon was allowed to proceed with thesurgery. All patients were monitored intraoperatively for systolic, diastolic, mean blood pressure, heart rate,and oxygen saturation. Any hypotension episode (defined as a reduction in mean arterial blood pressure> 30% of baseline) was treated with injection ephedrine 6 mg bolus and episodes of bradycardia (HR < 50 beats/min) was treated with injection atropine 0.02 mg/kg.After completion of surgery, the patients were shifted to PACU and monitored for the regression of sensory block to T₁₀ level, following which they were given the ultrasound guided 4- in -1 nerve block.

Procedure of the block: The patient was positioned in supine position with the ipsilateral leg kept in external rotation, slight abduction and knees slightly flexed (frog leg position). The medial femoral condyle wasmarked.

A linear high frequency ultrasound probe, ultrasoundSonositeMicromaxx® (Sonosite®, Bothell, WA, USA) wasused. After skin disinfection with povidone iodine, sterile drapes were applied.The linear probe (8–12 Hz) covered with sterile plastic sheath and with sufficient application of sterilised gel wasplaced over the femoral condyle and vastus medialis muscle identified and scanned proximally. The vastus and sartorius intersection (antero-medial intermuscular septum) were identified and the probe was taken proximal till the superficial femoral artery appears in the adductor hiatus. The probe was then slid slowly proximally till the descending genicularartery branching from superficial femoral artery is visualized in the hiatus. This point was the injection point which is 8-10 cm above the femoral condyle. Under all aseptic precautions,a22-gaugeechogenic needle wasused by an ultrasound-guided in-planefrom lateral to medial side under to reach perivascular region and after negative aspiration, the test drug was injected to spread around the femoral artery and also in a plane to push the Sartorius muscle up and hence blocking four nerves namely saphenous, obturator, sciatic and nerve to vastus medialis.

Subsequently, each patient was observed for pain, vitals and side effects at hourly intervals as mentioned in the proforma (i.e., 0, 1, 2, 4, 6, 12, 18 and 24 hours) for 24 hours by an anaesthesiologist blinded to group assignment. For the first 24 hours, the protocol for postoperative analgesia consisted of standard orders for injection i.v paracetamol 1gm i.vfor VAS > 4followed by injection i.v. diclofenacaqueous solution 1.5 mg/kg if pain not relieved with the former. For breakthrough pain, patients were treated with injection i.v. tramadol 0.5 mg/kg as and when required. The patients were evaluated for the Hemodynamic parameter variability in –

• heart rate

• systolic blood pressure

• oxygen saturation.

Statistical analysis

The data were recorded into Microsoft® Excel workbook 2019 and exported into SPSS v21.0 (IBM, USA) for statistical analysis. Categorical variables were expressed as frequency, percentage and compared using Chi square test. Quantitative variables were expressed as mean, standard deviation and compared using Student t-test. P value <0.05 was considered significant.

Ethical justification

The study was approved by IEC (HFW-H/DRPGMC/Ethics/2019/221; dated 21/12/2019) at Dr RPGMC Kangra at Tanda. All the patients were included after they agreed to give their consent.

The present study was aimed to compare the Hemodyanamic Variables both Intra-operatively & Post-operatively in ultrasound guided 4- in -1 nerve block with Bupivacaine in Combination with Dexmedetomidine in Two Doses for knee and below knee orthopaedic surgeries. After Institutional Ethics Committee approval and written informed consent, one hundred and eight patients of ASA I and II category, aged between 18–60 years, were recruited in the study. Eight patients, however, were excluded from the study as per the exclusion criteria. Fifty patients in each group completed the study successfully. 

A total of 100 patients were randomly divided into 2 groups. The groups made have been elaborated as following:

Group A - 29 ml of 0.125% bupivacaine with 0.5µg/kg dose of dexmedetomidine (1ml) making it to a total 30 ml solution, in USG guided 4 in 1 block.

Group B - 29 ml of 0.125% bupivacaine with 1µg/kg dose of dexmedetomidine (1ml) making it to a total 30 ml solution, in USG guided 4 in 1 block.

In this study, mean age of the participant was 40.64±11.44 years in Group A and 40.12±12.55 years in Group B ranging from 18 years to 60 years. Maximum participant in Group A (n=18) aged between 41 and 50 years and in Group B (n=17) were aged between 30 and 40 years. Only 10 participants aged below 30 in both the groups. The study population comprised of 36 males in Group A and 31 males in Group B and 14 females in Group A and 19 females in Group B. There was no significant difference of gender between both groups (P=0.287) (Table 1).

Table No-1: Distribution of participants according to socio-demographic variables

In this study, we compared three anthropometric characteristics namely height, weight, and BMI. The mean weight in group A was 65.12±8.59kg and in group B was 64.14±8.72 kg(P=0.573). The mean height in group A was 167.95±7.53cm and in group B was 165.71±7.49 cm (P=0.139). The mean BMI in group A was 28.21±3.25kg/m²and in group B was 27.62±3.75 kg/m² (P=0.408). There was no significant difference between both groups in terms of weight, height, and BMI (Table-1).

In this study, there was no significant comparison between both the groups according to ASA grade. Distribution of patients in ASA grade 1 is non-significant in group A as compared to Group B (P=0.827) In this study, mean duration of surgery in group A and group B was 84.70±30.60 min and 91.60±31.90 min respectively. There was no significant difference of duration of surgery between both groups (P=0.272). (Table-2)

Table No-2: Distribution of participants according to ASA grades and Mean Duration of surgery 

In this study, mean intraoperative heart rate from baseline to 120 min was comparable between both groups and was statistically non-significant(P>0.05) (Table-3).

Table-3: Intra-operative heart rate

In this study, mean intraoperative systolic BP from baseline to 120 min was comparable between both groups and was statistically non-significant(P>0.05) (Table-4).

Table -4 : Intra-operative Systolic BP

In this study, mean intraoperative systolic BP from baseline to 120 min was comparable between both groups and was statistically non-significant(P>0.05) (Table-5).

Table-5 : Intra-operative Diastolic BP

In this study, mean intraoperative SPO₂ from baseline to 120 min was comparable between both groups and was statistically non-significant(P>0.05) (Table-6).

Table-6 : Intra-operative Oxygen saturation

In this study, mean heart rate from 0-hour to 24-hourinterval post-block administration was comparable between both the groups.The differences in heart rate in all these time intervals were clinically not significant and no intervention was required in any of the patients.(P>0.05) (Table-7)

Table-7: Post-operative Heart rate

In this study, mean systolic BP from 0-hour to 24-hour interval post-block administration was comparable between both the groups (P>0.05)and was statistically non-significant(Table-8).

Table-8: Post-operative Systolic BP

In the present study, oxygen saturation from 0 hour to 24 hours post-block administration was comparable between both groups (P>0.05) during the entire study period and was statistically non-significant and no active intervention was required (Table-9).

Table -9: Post-operative Oxygen saturation

The recent surge of interest in peripheral nerve block is likely attributable to the advent of ultrasound guidance, as the benefits of ultrasound are believed to be related to enhanced accuracy of local anaesthetic deposition thus allowing the use of reduced doses of LA’s.

The evolution from central neuraxial blocks like combined spinal epidural etc. to regional blocks like the Femoral, sciatic, Adductor, combined femoral and sciatic for targeting pain free TKA has paved way to more and more research into the subject. As the knee joint is supplied by various nerves (genicular nerves) from the femoral, obturator and sciatic nerves; hence, needs a comprehensive yet simple technique for complete analgesia postoperatively.

This technique has not been studied much in detail. Hence, we compared the Hemodyanamic Variables  both Intra-operatively & Post-operatively of ultrasound-guided 4-in-1 block with bupivacaine in combination with dexmedetomidine in two doses for knee and below knee orthopaedic surgeries for postoperative analgesia.

In this study, both groups were comparable in terms of intraoperative and post-block hemodynamic variables such as heart rate, systolic and diastolic BP, and oxygen saturation.

In this study, mean intraoperative heart rate, systolic BP, diastolic BP & SPO₂from baseline to 120 min was comparable between both groups and statistically non-significant(P>0.05), Similary in the present study, oxygen saturation, mean heart rate and mean systolic BP  from 0-hour to 24-hour post administration of 4- in -1 block was comparable between both groups (P>0.05) and was statistically non-significant.

With the 4-in-block technique, we could not find much  literature regarding in terms of intraoperative and post-block hemodynamic variables s. As the technique is new and would require further studies.

The study concluded that both groups were comparable in terms of intraoperative and post-block hemodynamic variables such as heart rate, systolic and diastolic BP, and oxygen saturation.

Conflict of Interest: The authors declare that they have no conflict of interest

Funding: No funding sources

Ethical approval: The study was approved by the ESI Parwanoo.

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