European Journal of Cardiovascular Medicine

The International Association of the study of pain defines pain as “an unpleasant sensory or emotional experience associated with actual or potential tissue damage or

described in terms of such damage.” It is an unpleasant effect can result from surgical

stress elicit a consistent and well-defined metabolic response involving the release of

neuroendocrine hormones and cytokines, which lead to a myriad of detrimental effects

associated with significant psychological and physiological changes during surgery and post- operative period. This can be overcome by the use of suitable drugs and techniques.(1)

Regional anaesthetic techniques have specific advantages both for stand-alone anaesthesia and as analgesic supplements for intraoperative and postoperative care.

Decades of efforts to relieve surgical, postoperative and chronic pain, peripheral nerve

blocks proven to be boon. Regional anaesthesia besides reducing neuroendocrine stress response also reduces myocardial work and oxygen consumption by reducing heart rate, arterial pressure and left ventricular contractility.

Pain is the most common source of distress and modern practices of anaesthesia includes analgesia as its integral part. The opportunity to interrupt pain pathways at

multiple anatomic levels and ability to provide excellent operating conditions without

undue sedation or obtundation makes specific peripheral nerve blocks ideally suited for modern practice. Halsted2 in the year 1884 introduced the concept of nerve blocking. He “freed the cords and nerves of the brachial plexus, after blocking the roots in the neck with cocaine solution”.(2)

Brachial plexus regional anaesthesia nerve blockade is a time-tested technique for upper limb surgeries has become a mainstay of the anaesthesiologists’ armamentarium. German surgeon Kulenkampff (3) in 1912 performed the first supraclavicular brachial plexus block. More modern modifications of supraclavicular block include WINNIE AND COLLINS’S (4,5) subclavian perivascular technique and the “plumb-bob” technique of BROWN et al 1993 (6). Peripheral nerve block of upper limb includes the various techniques of brachial plexus block. Among brachial plexus blocks, interscalene, supraclavicular and axillary blocks have been routinely used for many years in our institute. Infraclavicular block has gained interest in recent times.

Infra clavicular brachial plexus block was first described by Bazy in the early 20^th century and was even included in LABAT’s textbook: regional anaesthesia in 19221.

In 1977, RAJ (7) and associates modified the infraclavicular technique by a lateral direction of the needle; thus, avoiding pneumothorax, and using the nerve stimulator to make the technique of locating the plexus more acceptable to the patients.(7,8,9).

In 1998 WILSON et al (10) .described an infraclavicular coracoid technique – which was adopted in this study, was undertaken to evaluate the sensory distribution and its clinical efficacy.

In the past few years infraclavicular block has become a method of increased interest. An effective use of PNS technology mandates knowledge of anatomy with respect to optimal needle insertion site to achieve needle tip-target nerve contact muscle innervations scheme of the targeted nerve to identify desired evoked motor response (EMR) ability to differentiate desired EMR from the alternate EMRs elicited by the stimulation of adjacent muscles and collateral nerves and the relationships of the adjacent neuromuscular structures generating these alternate EMRs to the targeted nerve. Therefore, an algorithm can be designed for needle redirection during PNS assisted PNB.

This study attempts to compare the clinical efficacy of infraclavicular and supraclavicular approach of brachial plexus block by using peripheral nerve stimulator with the following objectives:

PRIMARY OBJECTIVES:

To compare supraclavicular and infraclavicular block in terms of

1. Time to perform block
2. Onset of sensory and motor blockade
3. Duration of motor block
4. Time required for first rescue analgesia

SECONDARY OBJECTIVES:

To compare supraclavicular & infraclavicular block in terms of

1. Quality of block
2. Rate of complications

This study was a prospective observational study done in at a tertiary medical college in central India from 1 May 2021 to December 2022 on 60 patients, 30 patients in 2 groups (S and I) admitted for upper limb orthopaedic surgery.

Inclusion criteria:

1. Adult patients of age 18-60 years,
2. ASA grade 1 or 2 and
3. weighing between 45 to 70kg
4. posted for undergoing upper limb orthopaedic surgery and
5. giving consent for the procedure will be included in our study.

Exclusion criteria:

1. Patients with mental incapacity or language barrier,
2. BMI over 35,
3. anatomical variations,
4. coagulopathy,
5. allergy to amide local anaesthetics and Pregnant Women.

Sample size:

The study of Timsi R. Satan, et al (6) observed that duration of motor block in supraclavicular approach was 768±232 minutes and in infraclavicular approach was 822±224 minutes.

Taking these values as reference, the minimum required sample size with 80% power of study and 5% level of significance is 280 patients in each study group. For the sample size taking population as 60, total sample size calculated is 55. To reduce margin of error, total sample size taken is 60 (30 each group).

Patients were divided into 2 groups alternatively with 30 patients in each group:

GROUP S: Supraclavicular –subclavian perivascular approach

GROUP I: Surgery performed under Infraclavicular- coracoid approach

In our study the mean age of patients in 2 groups, Group S and Group I were 29.8 and 34.9 years with SD of 12.41 and 12.48 respectively. P value was 0.118. Males out-numbered females in our study.

Weight distribution in Group-S range from minimum of 45kg to maximum of 70 kg, with a mean of 55.6 kgs and the standard deviation of 7.7 kgs, and in Group-I weight of the patients ranges from 45-70kg, with a mean of 55.53 kgs, and the standard deviation of 9.9 kgs

(Table 1)

The mean time of onset of sensory block in 2 groups, Group S and Group I was 6.68 mins and 6.2 mins with SD of 1.03 and 1.26 respectively. P value was 0.117 which is not significant.

The mean time of onset of motor block in 2 groups, Group S and Group I was 13.17 mins and 13.20 mins with SD of 1.68 and 1.5 respectively. P value was 0.914 which is not significant. (Table 2)

Total duration of motor blockade in Group-S ranges from minimum 3 hours to the maximum of 7 hours, with the mean of 4.76 hours, and the standard deviation of 0.74 hours, and in Group-I, the motor blockade duration ranges from minimum 3 hours to the maximum of 5.5 hours, with the mean of 4.65 hours, and the standard deviation of 0.55 hours. P value was not significant.

Time required for first rescue analgesia in Group-S, ranges from minimum of 4 hours to the maximum of 8 hours, with the mean of 5.7 hours, and the standard deviation of 0.73 , and in Group-I, it was ranges from the minimum of 4 hours to the maximum of 8 hours, with the mean of 5.62 hours. P value was not significant.

The quality of block in 2 groups, Group S and Group I as per scoring of 1, 2 and 3 were 1 and 1, 1 and 2, and 28 and 27 respectively. P value was 0.839 which is not significant. (Table 3)

Successful block, that is involvement of four terminal nerves: In GroupS,2 out of 4 nerves were blocked in1 patient & needed to get converted to GA, 3 out of four nerves were blocked in 1 patient (3-3 %) for which supplementation given in the form of inj. ketamine/inj. propofol/inj. fentanyl and all four nerves were blocked in 28 patients (96.7 %). In group I, 2 out of 4 nerves were blocked in 1 patient & needed to get converted to GA, 3 out of four nerves were blocked in 2 patients (10 %) for which supplementation given in the form of inj midazolam 11.5 ml/inj propofol1-2 mg/kg iv or inj ketamine 1-1.5mg iv and all four nerves were blocked in 27 patients (90 %). Applying Chi square tests, it was found to be statistically insignificant. The ‘p’ value of 0.554 was statistically insignificant. P value insignificant.

The number of vessel puncture in group S was 2 (6.7%). There was no vessel puncture in group I. Applying Chi square test, the ‘p’ value was 0.150 (statistically insignificant). No other complications recorded in both the groups. (Table 4).

Brachial plexus block, like other regional anesthetics, offers specific advantage to the patient, surgeon, anaesthesiologist, and surgical facility, which may not be true for use of general anaesthesia. Regional anaesthesia is limited to a restricted portion of the body on which the surgery will be performed, leaving the other vital centers unaffected. Among the various approaches to brachial plexus blockade, Supraclavicular block (subclavian perivascular) as described by Winne and Collins (5) in1980, has been a very widely used approach due its rapid onset, dense blockade and high success rate. The risks of complication are rare with experienced hands, especially when a nerve locator is used. Several modifications of the original infraclavicular approach to the brachial plexus –Raj et al (7), Sims, and whiter suggest that the perivascular sheath may be injected in this area as an alternative to other approaches.

The infraclavicular approach was developed in the hope to overcome these limitations, but widespread use of Raj's infraclavicular brachial approach has not gained popularity, since most believe it requires the use of a nerve stimulator and a long needle able to penetrate both the pectoralis major and minor muscles, which can cause greater patient discomfort. It has recently gained favor for use with patients in whom the continuous block technique is desired, because maintaining an aseptic dressing at this site is more practical than at one in the axilla.

There have been numerous descriptions of the new infraclavicular approaches varying in their site of the needle insertion, success, and complication rate. Wilson et al (10). Described in 1998 an infraclavicular coracoid technique that is adopted in this study, which was undertaken to evaluate the sensory distribution of the infraclavicular brachial plexus block by the coracoid approach and its clinical efficacy.

In our study we found that the observed difference between the 2 study groups with respect to mean onset of time of sensory block, motor block and quality of block was found to be statistically not significant.

Siddharth S et al (7) in 2019 conducted a study where they found mean onset of sensory block in group S was 6.9 ± 1.58 min mean and in group I,it was 7.6 ± 1.34 min. The difference between the two groups was statistically significant with a p value of 0.019 (p<0.05). Also, mean onset of motor blockade in group S was 9.08 ± 1.96 min and in group I, it was 9.2 ± 1.69 min. The difference between the two groups was statistically not significant with a p value of 0.745 (p>0.05).

Ranganathan et al (8) in 2017 conducted a study where they found mean onset of sensory block in group S was 8.45±2.87 min mean and in group I, it was 6.43±2.61 min. The difference between the two groups was statistically significant with a p value of 0.006 (p<0.05). Also, mean onset of motor blockade in group S was 8.68 ± 3.50 min and in group I, it was 7.32 ± 2.90 min. The difference between the two groups was statistically not significant with a p value of 0.121 (p>0.05).

Our study yielded divergent outcomes in mean onset of sensory block from those of Siddharth S et al (7) (2019) and Ranganathan et al (8) (2017), emphasizing the importance of considering the potential impact of varying factors such as sample size, methodology, and statistical analysis in comparative studies while our study findings with respect to mean onset of motor block were consistent with the above 2 studies.

The quality of the block was evaluated in the intraoperative time. The quality of block achieved by brachial plexus block using either the supraclavicular or infraclavicular approach was compared, and a Chi-square test was performed. The results showed that there was no statistically significant difference between the two approaches, as indicated by a non-significant p-value.

Therefore, it can be concluded that both approaches are equally effective in achieving the desired block quality. The results of our study are in concordance with study done by Ranganathan et al (8), Siddharth S et al (7) and Chin Woo Yang et al (9).

Successful block is blockade in the four nerves to the elbow (musculocutaneous, median, ulnar and radial), that is involvement of four terminal nerves, In Group-S,2 out of 4 nerves were blocked in1 patient, 3 out of four nerves were blocked in 1 patient (3.3 %) and all four nerves were blocked in 28 patients (96.7 %). In group I, 2 out of 4 nerves were blocked in 1 patient, 3 out of four nerves were blocked in 2 patients (10 %) and all four nerves were blocked in 27 patients (90 %). Applying Chi square tests, it was found to be statistically insignificant. The ‘p’ value of 0.758 was statistically insignificant. The results of our study are in concordance with study done by Siddharth et al (7) , Ranganathan et al (8) & Chin Woo et al (9) in which they found quality of block statistically not significant between both the groups (p value > 0.05).

In our study, mean duration of motor block from scale 3 to 2 in group S was 4.73 ± 0.73 hours and in group I, 4.7 ± 0.44 hours. The difference between the two groups was statistically not significant with a p value of 0.547 (p> 0.05). The results of our study are in concordance with study done by Sandip W et al (11) , Siddharth S et al (7) and Chin Woo Yang et al (9).

Time required for first rescue analgesia is time interval between the onset of sensory block to the first requirement of analgesia. The mean time required of first dose of rescue analgesia in group S was 5.75±0.73 hours and in group I it was 5.62 ±0.62 hours. The difference between the two groups was not statistically significant with a p value of 0.445 (p>0.05).

Parvati Sreelal et al (13) in 2020 conducted a study in which time required for first rescue analgesia was compared between both the groups in which mean time required for first rescue analgesia in group S was 12.30 ± 0.404 hours & in group I was 12.358 ± 0.457hours. The difference between the two groups was not statistically significant with a p value of 0.64 (p>0.05). Siddharth S et al (7) in 2019 conducted a study in which time required for first rescue analgesia was compared between both the groups in which mean time required for first rescue analgesia in group S was 3.55 ± 0.401 hours & in group I was 3.705 ± 0.415 hours. The difference between the two groups was not statistically significant with a p value of 0.122 (p>0.05).

Chin Woo Yang et al (9) in 2010 conducted a study in which time required for first rescue analgesia was compared between both the groups in which mean time required for first rescue analgesia in group S was 12.71 ± 3.36 hours & in group I was 13.78 ± 2.91 hours. The difference between the two groups was not statistically significant (p>0.05).

The results of our study are in concordance with study done by Sandip W et al (11) & Genevieve A et al (12).

The number of vessel punctures in Group S was 2 (6.7%). There were no vessel punctures in Group I was nil (0%). Though seemingly significant clinically, applying Chi square tests, the ‘p’ value was 0.150 which is statistically insignificant. No other complications were noted in either group. Although the incidence of pneumothorax is often feared in infraclavicular block, it is an extremely rare as the needle is directed away from the chest cavity.

Sandip J et al (14) & Siddharth S et al (7) faced incidence of vessel puncture in SCB group more but was not statistically significant (p value >0.05%).

Parvati Sreelal et al (13), Ranganathan et al (8) & Chin W Yang et al (9) faced complications such as Horner’s syndrome, pneumothorax & vascular puncture in group S> group I but the rate of complications was not statistically significant (p value > 0.05%).

Our study has found that using a peripheral nerve stimulator to guide an infraclavicular block of the brachial plexus via the coracoid approach results in a comparable onset time for sensory and motor blockade as the peripheral nerve stimulator guided supraclavicular approach. Moreover, the success rate for achieving surgical anaesthesia was similar between the two approaches. However, the study identified that only two patients in the peripheral nerve stimulator guided supraclavicular block

group experienced vessel puncture. This could be attributed to the learning curve of residents with minimal experience in performing the block. To minimize or prevent such complications, the use of ultrasound could be helpful, but further research is necessary to explore this possibility.

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