|Year : 2020 | Volume
| Issue : 4 | Page : 644-652
To compare the efficacy of postoperative analgesia between clonidine and dexmedetomidine as adjuvants with 0.5% ropivacaine by ultrasound-guided supraclavicular brachial plexus block for upper limb surgeries: A prospective, double-blind, randomized study
Preeti Kumari1, Raj Bahadur Singh1, Kumar Saurabh2, Shilpi Pal3, Ganesh Kumar Ram1, Rakesh Kumar Anand4
1 Department of Anaesthesiology (Trauma and Emergency), Indira Gandhi Institute of Medical Sciences, Patna, Bihar, India
2 Department of Anaesthesiology, Ruban Memorial Hospital, Patna, Bihar, India
3 Department of Anaesthesiology, Calcutta National Medical College and Hospital, Kolkata, West Bengal, India
4 Department of General Surgery, ESI Medical College, Patna, Bihar, India
|Date of Submission||13-Apr-2021|
|Date of Acceptance||21-Apr-2021|
|Date of Web Publication||27-May-2021|
Dr. Raj Bahadur Singh
Department of Anaesthesiology (Trauma and Emergency), Indira Gandhi Institute of Medical Sciences, Patna, Bihar
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Context: The supraclavicular brachial plexus block is a very safe, useful and effective method for upper limb surgeries. Among local anesthetics, ropivacaine has special applications in neuraxial and peripheral nerve blocks due to its low cardiotoxicity and less toxicity to central nervous systems compared to bupivacaine and lignocaine. Dexmedetomidine is a newer and potent alpha-2 receptor agonist which has 10 times higher selectivity for alpha-2 receptors as compared to clonidine, So far, very few studies have been undertaken to compare the efficacy of clonidine and dexmedetomidine to provide and prolong postoperative analgesia, especially with the use of ultrasound for nerve localization. Aims: To compare the efficacy of postoperative analgesia between clonidine and dexmedetomidine as adjuvants with 0.5% ropivacaine by ultrasound-guided supraclavicular brachial plexus block for upper limb surgeries. Settings and Design: Prospective, randomised, double-blind interventional study. Subjects and Methods: Eighty patients of ASA grade I or II undergoing elective upper limb surgery were randomly divided into two groups:- Group RC (n = 40) received 35 ml of 0.5% ropivacine with 1 μg.kg−1 of clonidine.Group RD (n = 40) received 35 ml of 0.5% ropivacaine with 1 μg.kg−1 of dexmedetomidine. Statistical analysis used: The statistical software SPSS version 20 has been used for the analysis. By using Pearson's Chi-Square test for Independence of Attributes/Fisher's Exact. Continuous variables were expressed as Mean, Median, and Standard Deviation and compared across the groups using unpaired t-test. Results: In our comparative study, dexmedetomidine 1 μg.kg−1 with 35 ml of 0.5% ropivacaine provided significantly longer duration of postoperative analgesia and earlier sensory block as compared to clonidine 1 μg.kg−1 with same dose of ropivacaine in ultrasound-guided supraclavicular brachial plexus block. Conclusions: The ropivacaine-dexmedetomidine group in our study provided earlier sensory block and more prolonged postoperative analgesia as compared to ropivacaine-clonidine group. Thus ropivacaine-dexmedetomidine combination may be effectively used in all painful upper limb surgeries specially orthopaedic procedures.
Keywords: Analgesia, dexmedetomidine, orthopaedic surgeries, ropivacaine, supra-clavicular block, upper limb
|How to cite this article:|
Kumari P, Singh RB, Saurabh K, Pal S, Ram GK, Anand RK. To compare the efficacy of postoperative analgesia between clonidine and dexmedetomidine as adjuvants with 0.5% ropivacaine by ultrasound-guided supraclavicular brachial plexus block for upper limb surgeries: A prospective, double-blind, randomized study. Anesth Essays Res 2020;14:644-52
|How to cite this URL:|
Kumari P, Singh RB, Saurabh K, Pal S, Ram GK, Anand RK. To compare the efficacy of postoperative analgesia between clonidine and dexmedetomidine as adjuvants with 0.5% ropivacaine by ultrasound-guided supraclavicular brachial plexus block for upper limb surgeries: A prospective, double-blind, randomized study. Anesth Essays Res [serial online] 2020 [cited 2021 Sep 24];14:644-52. Available from: https://www.aeronline.org/text.asp?2020/14/4/644/316983
| Introduction|| |
Local anesthetics administered during regional nerve block are utilized to provide intra-operative and postoperative pain relief in many surgeries by blocking traffic signal to the dorsal horn of the spinal cord. The brachial plexus block is a safe and useful method for upper limb surgeries under regional anesthesia. Among the various approaches of brachial plexus block, supraclavicular approach is considered the easiest and most effective as it is performed at the trunk level of the brachial plexus where it is presented compactly.
Lignocaine, Bupivacaine is commonly used local anesthetics but Ropivacaine has also been used successfully recently. In order to potentiate the duration of brachial plexus block and to prolong postoperative analgesia, several adjuncts have been studied which includes opioids, dexamethasone, midazolam, neostigmine, bicarbonate, hyaluronidase, and alpha-2 agonists. Among alpha-2 agonists, clonidine has been used for many years as an adjuvant which has partial agonistic activity at alpha-2 receptors. This leads to analgesia, sedation and sometimes hypotension with bradycardia due to reduced sympathetic outflow. Thus as an adjunct to local anesthetics for brachial plexus block, clonidine results in reduced onset time, greater extent of block and increased duration of analgesia at the expense of sedation and hypotension. Paradoxically, clonidine may have alpha-1 agonistic action with a higher dose which can counterbalance its alpha-2 receptor-induced hemodynamics.,,,,,
Dexmedetomidine is a newer, highly selective, potent alpha-2 agonist which has 10 fold higher selectivity for alpha-2 receptors as compared to clonidine and very few studies have so far been undertaken to compare its efficacy with clonidine to provide and prolong postoperative analgesia., Moreover, those studies have been done with the use of peripheral nerve stimulator.
This study is intended to compare the efficacy of postoperative analgesia between dexmedetomidine and clonidine with 0.5% ropivacaine following supraclavicular brachial plexus block for upper limb surgeries with the help of ultrasound.
| Subjects and Methods|| |
The study was conducted after obtaining approval from the institutional ethical committee and scientific committee, in the Department of Anesthesiology, of a tertiary health care facility over a period of 18 months. After explaining in detail the merits and demerits of the study to the patients in their own language, written informed consent was obtained from each of them. Eighty patients fulfilling the inclusion criteria scheduled to undergo elective upper limb surgeries under ultrasound-guided supraclavicular brachial plexus block were sampled sequentially and included in the study. The patients were assured of their right to withdraw from the study, at any point of time during the study period.
Patients of both sexes aged between 18 and 60 years and of ASA physical status 1 and 2 scheduled for upper limb surgeries of about 2 h duration were included in the study. Inclusion criteria were Patients giving valid consent, Patients of ASA physical status 1 and 2, Patients of both sexes, Patients aged between 18 and 60 years of age and Patients scheduled for upper limb surgeries. Exclusion criteria were patient refusal, Any bleeding disorder or on anticoagulant therapy, Infection at the site of injection, Neuromuscular diseases, Pregnancy, Body mass index > 35, Chronic analgesic therapy or sedatives or antipsychotics, Incomplete block or failure of the block and Hypersensitivity to any of the drugs used.
Randomization was done by using a computer-generated random number table. All patients were randomly allocated into two groups (Group RC and RD) [Figure 1].
Group RC (n = 40): Received 35 ml of 0.5% ropivacaine + clonidine 1 μg.kg−1 of body weight (made upto 2 ml with normal saline).
Group RD (n = 40: Received 35 ml of 0.5% ropivacaine + dexmedetomidine 1 μg.kg−1 of body weight (made upto 2 ml of normal saline).
Total volume of drug injected in both the group was 37 ml and to maintain double-blind design, an investigator not involved in the study mixed the anesthetic solution for the anesthetist who was performing the block.
Preanesthetic evaluation was done in all patients through a review of clinical findings and investigation reports on the night before surgery.
After bringing the patient to the block room, where all the resuscitation equipment and intralipid solutions were kept ready, side to be blocked was identified and allergic history confirmed. Standard monitors like electrocardiography, pulse oximeter, noninvasive blood pressure monitor was connected for intraoperative monitoring. Intravenous access was secured preferably with 18 G cannula in the upper limb opposite to that undergoing surgery.
The patient was placed in supine position with hands by the side and head propped up to 30 degrees. Philips machine (ultrasonography model En Visor Version C.1.3) with 8-12 MHZ linear probe was used, adjusted for depth, focus and brightness to give good quality image. Betadine solution was used to decrease the air probe interface. Supraclavicular area was scanned first at the midpoint of clavicle in supraclavicular fossa. The proble was tilted caudally and first, the subclavian artery was identified, then first rib, pleura, and lung tissue identified (C5C6) was identified above the subclavian artery and [C8T1] was identified inferior and laterally. Using in-plane method, local anesthetic 2% lignocaine was injected into skin 1-2 cm from lateral side of probe. Using Stimuplex (22 G × 2”0.70 × 50 mm) blunt needle loaded with 0.5% ropivacaine with additives in 20 ml syringe, keeping the needle tip and whole needle in vision, the needle was inserted inferior and lateral to subclavian artery to block C8T1. Next, the needle was redirected above the subclavian artery to block C5C6. During injection, negative aspiration was performed every 3-–4 ml to avoid intravascular injection.
Oxygen (2 L/min) was administered via a face mask. Hypotension, defined as >20% fall in baseline MAP or a MAP <65 mmHg was treated with IV fluids, and when required, incremental intravenous (i.v.) doses of injection phenylephrine 100 μg was given. Bradycardia, defined as heart rate (HR) <50 beats/min, when occurred, was treated with iv atropine 0.3–0.6 mg.
Anesthesia machine with all necessary equipment and drugs needed for the administration of general anesthesia and emergency resuscitation was kept ready to manage failure of block or adverse reactions occurring anytime during procedure.
Hemodynamic parameters (HR, mean arterial pressure [MAP]) were recorded at 10 min, 20 min, 30 min, 45 min, 60 min, 90 min, and 120 min.
Onset time of sensory blockade (time between injection for brachial plexus block and complete abolition of pain sensation) was assessed by needle prick test with a 25 G hypodermic needle in all 4 nerve areas for every 5 min till 30 min after completion of drug injection. The nerve areas tested were as follows:
- Lateral side of the palm, thumb, second and third finger for median nerve
- Lateral side of the dorsum of the hand for radial nerve
- Medial side of the palm and the dorsum of the hand, fourth and fifth finger for ulnar nerve
- Lateral side of the forearm for musculocutaneous nerve.
Sensory onset was considered when there was a dull sensation to pinprick along the distribution of any of the above-mentioned nerves. Complete sensory was considered when there was complete loss of sensation to pinprick.
Sensory block was graded as:
- Grade 0-sharp pinprick sensations felt
- Grade 1-analgesia, dull sensation felt
- Grade 2-anaesthesia., no sensation felt.
Motor block was assessed by same observer every min till 30 min of drug injection by:
- Thumb adduction for ulnar nerve
- Thumb abduction for radial nerve
- Thumb opposition for median nerve
- Flexion of the elbow and pronation of the forearm for the musculocutaneous nerve.
The block was considered incomplete when any of the following segments supplied by median, radial, ulnar and musculocutaneous nerve did not have analgesia even after 30 min of drug injection. These patients were supplemented with iv fentanyl (1 μg.kg−1) and midazolam (0.2 mg.kg−1).When more than 1 nerve areas did not develop analgesia (unaffected) it was considered a failed block. In this case, general anesthesia was administered.
The surgical incision was allowed only after confirming the success of the block.
Intravenous fluids were administered continuously.
Patients were continuously observed for intraoperative complications such as hypotension, bradycardia, nausea, vomiting, drowsiness, convulsions, pneumothorax, and phrenic nerve palsy.
Nausea and vomiting were treated with injection ondensetron 0.1 mg.kg−1 i.v.
All physiological variables and drugs used during the procedure were recorded in a data collection sheet.
Patients were observed in the recovery room for haemodynamic stability and side effects (hypotension, bradycardia, nausea, vomiting, convulsion, pneumothorax, and phrenic nerve palsy etc.,) and the need for additional medications were recorded. Patients moved to ward after normalization of vital parameters.
In the ward, patients were monitored for 3 h by a member of the anesthesiology team and thereafter by the nursing staff on duty for 24 h following the end of surgery. Both were blinded to the group allocation of the patients.
The following parameters were recorded in the recovery room and ward for 24 h.
- Haemodynamic parameters (map, HR): Immediately after operation and at 30 min, 60 min, 90 min and 120 min after the end of operation.
- Duration of postoperative analgesia (denoted by the time interval between onset of sensory block and first dose of rescue analgesia based on patients need or request) was recorded in each patient.
- Assessment of pain (was done by visual analog scale [VAS] score at skin closure (0 h), 2 h, 4 h, 6 h, 12 h 24 h. VAS score of 0 denoted no pain and score of 10 denoted worst pain.
- 1–2 : Least pain
- 3–4: Mild pain
- 5–-6: Moderate pain
- 7–8: Severe pain
- 9–10: Excruciating pain.
Inj diclofenac sodium 75 mg im was given as rescue analgesic when patient felt pain or VAS was more than 4.
- Degree of sedation: Was assessed by modified Wilson sedation scale ranging from 1 to 4 at 0, 2, 4, 6, 12, 24 h following skin closure.
Modified Wilson Scale: 1 = oriented patient, 2 = drowsy but easily aroused, 3 = arousable only to mild physical stimulation, and 4 = unarousable to mild physical stimulation.
- Side effects: Like hypotension, bradycardia, nausea, vomiting, drowsiness, convulsions, pneumothorax and phrenic nerve palsy recorded and treated accordingly.
| Results|| |
[Figure 1] shows consort flow diagram of patients of the study. Demographic data regarding age, body weight and height in both the groups were comparable with the differences being statistically insignificant (P > 0.05) [Table 1].
Sex distribution of patients in the two groups showed that the ratio was comparable in both the groups with the differences being statistically insignificant (P > 0.05) [Table 2].
ASA status of patients was comparable in both the groups with the difference being statistically insignificant (P > 0.05) [Table 3].
|Table 3: Distribution of patients as per their American Society of Anesthesiologists status|
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Mean duration of surgery was comparable in both the groups with the difference being statistically insignificant.(P > 0.05) [Table 4].
Preoperative baseline HR and MAP which were comparable in both groups. Mean values of consecutive three readings were taken to be the baseline value. These readings were taken prior to performing the block. The difference was statistically insignificant (P > 0.05) [Table 5].
[Figure 2] shows the baseline HR and changes in intra-operative HRs at fixed time intervals after performing the blocks in both the groups. Intraoperative HR showed decrease from baseline in both the groups beyond 45 min. A significant difference was noted between the groups at 60 and 90 min (P < 0.05). HR decreased more in RD group than RC group).
[Figure 3] shows the baseline MAP and the changes in intra-operative MAPs at fixed time intervals after performing the blocks in both the groups. Intraoperative MAP slightly decreased from baseline in both the groups beyond 30 min but the difference between the groups was insignificant (P > 0.05).
[Figure 4] shows the changes in mean postoperative HRs in both the groups at fixed time intervals which were comparable in the two groups with the difference being statistically insignificant (P > 0.05).
[Figure 5] showing the changes in mean postoperative MAP in both the two groups at fixed time intervals which were comparable with the difference being statistically insignificant (P > 0.05).
Table showing the meantime of onset of sensory block in the four nerve areas in the two groups. Onset time (time between institution of brachial plexus block and total abolition of pain sensation) was assessed by needle (25G) prick test in all the 4 nerve areas every 5 min until 30 min.
The onset of sensory block in radial nerve was earlier in Group RD than in Group RC (P < 0.05).
In the other three nerves, the onset time was comparable and differences were statistically insignificant (P > 0.05) [Table 6].
|Table 6: Mean time of onset (minutes) of sensory block in the 4 nerve areas|
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Table showing the comparison of the mean times of 1st rescue analgesia, i.e., the duration of postoperative analgesia after brachial plexus block between the two groups. The duration of postoperative analgesia was significantly longer in Group RD compared to Group RC (P < 0.05) [Table 7] and [Figure 6].
[Figure 7] and [Figure 8] shows the mean VAS scores of the groups in the postoperative period at fixed time intervals. It was observed that the scoring were similar up to 4 h in both the groups after which Group RD showed a lower score than Group RC and the differences being statistically significant (P < 0.05) at 6 h, 12 h and 24 h.
|Figure 7: Postoperative mean VAS scores at fixed time intervals of the two groups|
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[Figure 9] shows the post-operative mean sedation scores of the two groups at fixed time intervals. The degree of sedation was assessed by Modified Wilson's Sedation Scale. It was observed that all patients in both the groups were oriented without sedation at any given time.
No hypotension occurred in either of the groups.
[Figure 10] shows the occurrence of bradycardia in both the groups. Bradycardia occurred in 1 patient in RC group and 3 patients in RD group but the difference between two groups were statistically insignificant (P > 0.05).
[Figure 11] showing the occurrence of nausea/vomiting in both the groups. It occurred in 3 patients in RC group and 1 patient in RD group but the difference between two groups were statistically insignificant (P > 0.05).
[Figure 12] showing the occurrence of drowsiness in both the groups. It occurred in 2 patient in RD group and none of the patients in RC group became drowsy and the difference between two groups were statistically insignificant (P > 0.05).
| Discussion|| |
Eighty patients fulfilling the inclusion criteria scheduled to undergo elective upper limb surgeries under US-guided supraclavicular brachial plexus block were included in the present study. The patients were randomly allocated into two groups with 40 patients in each group.
- RC group received 1 μg.kg−1 clonidine with 35 ml of 0.5% ropivacaine
- RD group received 1 μg.kg−1 dexmedetomidine with 35 ml of 0.5% ropivacaine.
In our study, the demographic data as regards to age, weight, height, sex, ASA physical status and duration of surgery were compared and the differences between the parameters between two groups were statistically not significant (P > 0.05) [Table 1], [Table 2], [Table 3], [Table 4].
In our study, the dexmedetomidine group (RD) showed longer mean duration of analgesia, earlier onset of duration, lower mean postoperative VAS scores, lower intraoperative mean HR as compared to the clonidine group (RC) Significantly whereas there was an insignificant difference in MAP, onset of sensory block, sedation scores, and incidence of side effects. Such as bradycardia, hypotension, nausea, vomiting, drowsiness, convulsions, pneumothorax, and phrenic nerve palsy.
In our study, ropivacaine was chosen as the local anesthetic because of its low cardiotoxicity. According to Rashique et al., maximum dose of ropivacaine was 4 mg.kg−1 and according to Shonfeld et al., it was 3 mg.kg−1. For our patients, we selected a dose of 35 ml of 0.5% ropivacaine.
Eldjam et al. stated that clonidine as an adjuvant into the brachial plexus sheath was an attractive alternative to epinephrine. According to El Saied et al., doses of clonidine as high as 150 μg as adjuvant caused prolongation of analgesia without any changes in onset time and side effects. According to Bernard et al., the best dose to use clinically was 30-–90 μg for peripheral nerve blocks, which improved the quality of blocks and limited the side effects. Swami et al. employed clonidine 1 μg.kg−1 with ropivacaine 35cc in supraclavicular brachial plexus block. We used the same dose in our study.
According to Memis et al., dexmedetomidine was approximately 8 times more selective towards alpha-2 adrenoceptors compared to clonidine. Das et al. in a study employed 100 μg of dexmedetomidine with 30 ml of 0.5% ropivacaine in supraclavicular brachial plexus block and found the prolongation of postoperative analgesia with no side effects. Swami et al. and Chinnappa et al. employed 1 μg.kg−1 dexmedetomidine with 35 ml of 0.25% ropivacaine and 30 ml of 0.5% ropivacaine respectively for comparative studies of clonidine in supraclavicular brachial plexus block. We employed the same dose of dexmedetomidine in our study.
Ultrasound-guided technique of supraclavicular brachial plexus block was employed in our study for better localization of nerves.
According to Brummett et al.,, there is prolongation of sensory and motor block with both clonidine and dexmedetomidine when used with local anesthetics. In spite of that many authors did not assess motor block while studying postoperative analgesia following supraclavicular block with LA-alpha2 receptor combination like Eldjam, Bernard, Culebras, Nallam. In our study, we also did not assess motor block while comparing analgesic efficacy of two groups of drugs combination in ultrasound-guided supraclavicular brachial plexus block.
Mean duration of analgesia of dexmedetomidine group (RD) in our study was 1262.33 ± 90.07 min which was significantly longer than that in clonidine group (RC) which was 855.35 ± 41.62 min [Table 7].
In our study, the duration of analgesia in dexmedetomidine group (RD) significantly outlasted the analgesic duration of clonidine group (RC). The finding was confirmed by many other authors like Swami, Sebastian, Bafwa, Tripathi, etc.
Singh et al. observed the effects of adding 150 μg of clonidine to 40 ml of 0.25% bupivacaine in supraclavicular brachial plexus block and found the significant prolongation of postoperative analgesia as assessed by visual analogue score.
The onset of sensory block in our study was shorter in dexmedetomidine group (RD) as compared to the clonidine group (RC) though the difference was not statistically significant [Table 6].
Our finding was similar to the findings of Swami et al. and Tripathi et al. who could not find a statistically significant difference in the onset of the sensory block between clonidine and dexmedetomidine as adjuvant to supraclavicular brachial plexus block.
Regarding mean HR, there was a fall in both Clonidine (RC) and Dexmedetomidine (RD) groups from the baseline value beyond 45 min of intraoperative period. Incidence of bradycardia(<50 bpm) was more with dexmedetomidine group as compared to clonidine group (3 out of 40 i. e. 7.5% v/s 1 out of 40 i. e. 2.5%) which was statistically insignificant [Figure 2]. Between the groups, unlike MAP, the fall in mean HR in dexmedetomidine group was significantly more than that in the clonidine group at 60 and 90 min of intraoperative period. In both groups, MAP and HR came back to normal within 120 min from the time of injection [Figure 2] and [Figure 3].
Regarding haemodynamic changes with dexmedetomidine, our study confirmed the finding of Vorobeichik et al. who conducted a meta-analysis to assess the effect of dexmedetomidine as an adjuvant to local anesthetics brachial plexus blockade. According to them, besides significant prolongation of sensory and motor block, dexmedetomidine at 0.75–1 μg.kg−1 dose caused bradycardia. These side effects according to them were transient and reversible and did not require any intervention or cause any long term consequences in any patient.
Also in our study, we observed that radial nerve was blocked significantly earlier in Group RD in comparison to Group RC (RC 8.50 ± 3.04 vs. RD 6.50 ± 2.58) with P = 0.002. Sensory block in the other three nerve areas (ulnar, median, and musculocutaneous) were also earlier in Group RD than Group RC but the differences were statistically insignificant P > 0.05. In comparison to the other three nerves, radial nerve was blocked earlier in both the groups [Table 6].
Future studies may be undertaken to find out if hemodynamic response could be further attenuated with lower dose of dexmedetomidine as an adjuvant with local anesthetics in supraclavicular brachial plexus block.
| Conclusion|| |
In our comparative study, dexmedetomidine 1 μg/kg with 35 ml of 0.5% ropivacaine provided significantly longer duration of postoperative analgesia and earlier sensory block as compared to clonidine 1 μg/kg with same dose of ropivacaine in ultrasound guided supraclavicular brachial plexus block. Intraoperative fall in heart rate was significantly more in ropivacaine-dexmedetomidine group. There was no significant difference between two groups regarding mean arterial pressure and sedation and other side effects.
The ropivacaine-dexmedetomidine group in our study provided earlier sensory block and more prolonged postoperative analgesia as compared to ropivacaine-clonidine group. Thus ropivacaine-dexmedetomidine combination may be effectively used in all painful upper limb surgeries specially orthopaedic procedures.
Future studies may be undertaken with even lower doses of dexmedetomidine as adjuvant to balance its effect and side effects in ultrasound guided supraclavicular brachial plexus block for upper limb surgeries.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11], [Figure 12]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]