|Ahead of print publication
A comparative study of sodium bicarbonate and hyaluronidase on pain perception, anesthesia, and akinesia during peribulbar anesthesia for cataract surgery
Priyanka Sodani1, Sandeepika Dogra2, Dev Raj3, Vabita Bhagat1
1 Department of Ophthalmology, Government Medical College, Kathua, Jammu and Kashmir, India
2 Department of Anesthesia and Critical Care, Government Medical College, Kathua, Jammu and Kashmir, India
3 Department of Community Medicine, Government Medical College, Jammu, Jammu and Kashmir, India
|Date of Submission||18-Oct-2021|
|Date of Decision||07-Apr-2022|
|Date of Acceptance||13-Apr-2022|
|Date of Web Publication||31-May-2022|
Department of Anesthesia and Critical Care, Government Medical College, Kathua, Jammu and Kashmir
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: An ideal anesthetic solution should provide good anesthesia and akinesia with minimal pain on injection. Aims: The aim of this study is to determine the effect on pain perception and efficacy of sodium bicarbonate over hyaluronidase in the local anesthetic mixture during peribulbar anesthesia. Settings and Design: A prospective, randomized, double-blind study. Materials and Methods: An independent observer labeled two injections as A (hyaluronidase 1500 IU in 30 mL of lignocaine) and B (7.5% sodium bicarbonate 1 mL in 30 mL of lignocaine). Group 1 was injected with injection A while Group 2 was injected with injection B. The visual analog scale (VAS) was used to determine the intensity of pain. Onset and degree of anesthesia and akinesia were recorded. Statistical Analysis: Computer software Microsoft Excel SPSS version 26 (Chicago Inc) for windows was used. The qualitative data and quantitative data were reported as proportions and mean ± (standard deviation), respectively. Chi-square test for proportions was used for the comparison of qualitative variables and unpaired Student's t-test was used to test the significance between quantitative variables. P < 0.05 was considered statistically significant. All P were two-tailed. Results: Out of 123 patients, 23 were excluded from the study. Hundred patients were divided into Group 1 and Group 2. The mean age in Group 1 was 64.92 ± 10.77 years while in Group 2 was 62.86 ± 11.17 years. The mean heart rate and mean systolic blood pressure in both groups were statistically insignificant. Group 2 experienced very less pain (mean pain score VAS = 5.12 ± 1.17) as compared to Group 1 (mean pain score was 7.16 ± 1.09) and the difference between both the groups was found to be statistically significant. There was a significant difference in the onset of anesthesia in both groups (P = 0.001). In the sodium bicarbonate group, the onset was faster. The onset of akinesia was better in Group 1 (4.76 ± 2.06 min). Grading of akinesia was better in Group 1. Conclusion: Sodium bicarbonate reduces pain on injection in peribulbar anesthesia and also results in a quicker onset of anesthesia.
Keywords: Hyaluronidase, pain, peribulbar anesthesia, sodium bicarbonate
|How to cite this URL:|
Sodani P, Dogra S, Raj D, Bhagat V. A comparative study of sodium bicarbonate and hyaluronidase on pain perception, anesthesia, and akinesia during peribulbar anesthesia for cataract surgery. Anesth Essays Res [Epub ahead of print] [cited 2022 Jul 1]. Available from: https://www.aeronline.org/preprintarticle.asp?id=346396
| Introduction|| |
The ideal anesthesia would be one that provides adequate pain relief during surgery and postoperatively, is easy to administer, and have minimal complications. Local anesthesia is the most common form of anesthesia used for the patient undergoing cataract surgery. Several techniques and solutions have been used for local anesthesia to increase the efficacy of an anesthetic solution such as varying the pH, titrating the volume of anesthetic, or adding hyaluronidase. The prerequisites for better surgical outcomes are good surface anesthesia, akinesia, and hypotony of extraocular muscles.
Hyaluronidase has been used for the better diffusion of anesthetic solution. It acts by depolarization of hyaluronic acid to tetrasaccharide, which causes the interstitial barrier to liquefy, causing diffusion of anesthetic solution., However, its pain on injection, cost, shorter half-life, and difficult availability are the chief drawbacks. Sodium bicarbonate decreases the pain on injection by increasing the pH of the anesthetic solution., Galindo reported that by altering the pH of the local anesthetic solution with sodium bicarbonate mixed solution, the time of onset of anesthesia could be reduced and the spread of neural blockade enhanced significantly. There are very few studies done till now to compare the pain perception with pH adjusted anesthetic solution with an acidic anesthetic solution. Furthermore, it is cheaper, easily available, and has a longer shelf life.
The present study determined the effect on pain perception and efficacy of a 7.5% sodium bicarbonate buffered mixture of 2% lidocaine and 0.5% bupivacaine with hyaluronidase mixed with 2% lidocaine and 0.5% bupivacaine.
| Materials and Methods|| |
The present study is a prospective, randomized, double-blind study. Consecutive 123 patients electively undergoing manual small-incision cataract surgery with intraocular lens implantation in a peripheral medical college, during 14 months period from September 2020 to November 2021, were included in the study. The sample size was calculated on the basis of effect size 0.06, type 1 errorα = 0.05, and type 2 errorβ = 0.2 using G* power software (version 184.108.40.206) and it came out to 45. However, we have considered a rounded number, i.e., 50 participants in each group. Written informed consent was obtained from each patient to participate in this study. Ethical approval was obtained from the institutional ethical committee and the study was conducted adhering to principles of the Declaration of Helsinki.
All patients above 18 years of age admitted for manual small-incision cataract surgery under local anesthesia were included in the study.
Patients below 18 years, uncooperative patients, patients with profound cognitive impairment, patients having ocular or extraocular trauma, any previous intraocular surgery, patients on preoperative sedatives, and patients with uncontrolled systemic disorders were excluded from the study. Patients with an American Society of Anesthesiologists Physical Status Classification (ASA PS) class > II were also excluded from the study.
All patients with even serial numbers were allocated to Group 1 and all patients with odd serial numbers to Group 2. Anesthetic injections were labeled A and B by an independent observer. The surgeon, anesthesiologist, and patients were asked about the contents of the bottle. The contents of the bottle were revealed before statistical analysis. Group 1 was injected with the anesthetic mixture containing 0.5% of bupivacaine (1.5 mL) (trade name Anawin, Manufacturer: Neon) and 2% of xylocaine (3.5 mL) (trade name Lox, Manufacturer: Neon) with hyaluronidase (1500 IU in 30 mL of lignocaine) (trade name Hynidase, manufacturer; Shreya Life Sciences Pvt Limited). Group 2 was injected with the anesthetic mixture containing 0.5% bupivacaine (1.5 mL) and 2% xylocaine (3.5 mL) with 7.5% sodium bicarbonate (1 mL in 30 mL of lignocaine) (trade name BICARB, manufacturer; MediLife Health Care). The contents of the bottle of an anesthetic mixture for both the groups were disclosed after completion of the study but before analysis. One milliliter sodium bicarbonate (7.5%) was added very slowly, dropwise in 30 mL of lignocaine to avoid precipitation. The basic solution (sodium bicarbonate) has to be added carefully. If too much is added, pH rises too far and the noncharged basic form gets precipitated and is detected as white clouding of solution.
Single-point peribulbar anesthesia was administered by the person who was unaware of the constituents of the mixture at the infratemporal quadrant in all the cases. A total of 5 mL of local anesthetic solution were injected at the junction of medial 2/3rd and lateral 1/3rd of the lower lid with the eye in the primary position of gaze. The visual analog scale (VAS) was used to determine the intensity of pain on drop anesthesia and peribulbar block anesthesia [Figure 1]. The onset of anesthesia and akinesia was noted from the point of injection to the diminution of ocular movements and was defined by the grading of anesthesia and akinesia as below.
Grading of anesthesia and akinesia
Grade 1: Complete anesthesia and akinesia as demonstrated by:
- Complete absence of eye movements
- Complete anesthesia of cornea and conjunctiva
- Painless insertion of superior rectus bridle suture.
Grade 2: Akinesia and anesthesia are considered adequate for safe intraocular surgery as demonstrated by:
- Eye movements <15° in any gaze
- As above
- As above.
Grade 3: Unsuccessful akinesia and anesthesia as judged by:
- Eye movements more than 15° in any gaze
- As above
- Painful insertion of superior rectus bridle suture.
The onset of akinesia and anesthesia was checked from 1 min till 10 min. Patients with Grade 3 akinesia were given a supplement injection of the same anesthetic mixture after 10 min. The duration of anesthesia and akinesia was noted. Patients were also observed for any side effects.
All the collected data were entered into the Microsoft Excel sheet and then analyzed using computer software Microsoft Excel SPSS version 26 (Chicago Inc) for Windows. The qualitative data and quantitative data were reported as proportions and mean ± (standard deviation), respectively. Chi-square test for proportions was used for the comparison of qualitative variables and unpaired Student's t-test was used to test the significance between quantitative variables. P < 0.05 was considered statistically significant. All P were two-tailed.
| Results|| |
Out of 123 admitted patients, 23 patients were excluded (11 patients had uncontrolled hypertension, six patients had uncontrolled diabetes mellitus, three patients had ASA PS class >II, two patients had a history of ocular trauma, and one patient had profound cognitive impairment) from the study. Groups 1 and 2 had 50 patients each.
The mean age in the hyaluronidase group (Group 1) was 64.92 ± 10.77 years, while in the sodium bicarbonate group (Group 2) was 62.86 ± 11.17 years which was statistically insignificant (P = 0.35). There was no statistically significant difference between the other characteristics of the patients such as gender and eye [Table 1] and [Table 2]. The mean heart rate in Group 1 was 81.82 ± 12.37 and in Group 2 was 80.44 ± 11.24; the values were statistically insignificant (P = 0.584). Similarly, the mean systolic blood pressure in Group 1 and Group 2 was 140.96 ± 15.36 and 140.84 ± 14.40, respectively, and was comparable (P = 0.40). Similarly, the comparison between diastolic blood pressure and SpO2 was statistically insignificant [Table 3]. It is evident from [Table 4] that when drops of lignocaine 4% were administered, Group 1 experienced more pain (mean pain score, i.e., VAS = 1.78 ± 1.04) as compared to Group 2 (mean pain score, i.e., VAS = 1.68 ± 1.02), but the difference between the pain scores was statistically insignificant (P = 0.628). Whereas, when injection of both the anesthetic mixtures was administered, Group 2 experienced very less pain (mean pain score, i.e., VAS = 5.12 ± 1.17) as compared to Group 1 (mean pain score was 7.16 ± 1.09), and the difference between both the groups was found to be statistically significant (P = 0.001). The mean time of onset of anesthesia in Group 1 was 3.40 ± 0.95 min and the mean time of onset of anesthesia was 2.62 ± 1.21 min. There was significant difference in the onset of anesthesia in both the groups (P = 0.001). In the sodium bicarbonate group, the onset was faster as compared to the other groups. However, the onset of akinesia was better in Group 1 (4.76 ± 2.06 min) as compared to Group 2 (6.64 ± 2.18 min). The time difference was also statistically significant (P = 0.001). Grading of akinesia was also better in Group 1 as compared to Group 2 [Table 5]. There were no systemic or ocular adverse effects recorded in both groups. There were very few cases of peribulbar/subconjunctival hemorrhage, vitreous bulge, and forward thrust. The incidence of complications was similar in both groups with no statistical significance.
|Table 4: The comparison of the visual analog scale score of the patients|
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| Discussion|| |
In developing country like India, cataract remains the most common cause of treatable blindness. Cataract surgery has progressed from large incisions to smaller incisions. Similarly, anesthesia in cataract surgery has progressed from general anesthesia to local anesthesia to topical anesthesia. In 1949, Atkinson reported the advantages of hyaluronidase in anesthetic solution to allow for injecting a large volume of anesthetic agent and to achieve early akinesia and anesthesia. Ophthalmologists are shifting to topical anesthesia following the demands of patients because of the pain of the injection during peribulbar anesthesia. However, many studies have shown that surgeon comfort was better with peribulbar anesthesia as compared to topical anesthesia., A study by Dole et al. even reported that discomfort is more to the patient as well as surgeons in topical anesthesia as compared to topical anesthesia. Hence, there was a need for a study to look out for other measures to reduce pain during peribulbar anesthesia. Our study has compared the effect of sodium bicarbonate (7.5%) and hyaluronidase (1500 IU) on pain perception during the peribulbar block in cataract surgery.
In our study of 100 patients (50 in Group 1, hyaluronidase group, and 50 in Group 2, sodium bicarbonate group), the age, gender, educational status, and ASA PS of the studied patients were comparable between the two groups (P > 0.05). There was no statistical difference in heart rate, mean systolic BP, diastolic BP, and sPO2 after anesthetic injection in the two groups (P > 0.05).
The time elapsed before the onset of anesthesia was significantly shorter in Group 2 as compared to Group 1. This corresponds with the study by Gupta and Kapoor. In a study by Srinivasan et al., the time of onset of anesthesia and akinesia was not statistically significant in the two groups. Mehta et al. also observed that raising the pH of anesthetic solution significantly reduced the onset of sensory and motor block R. However, in their study, the duration of the block was also increased contrary to our study.
The onset of akinesia was found to be faster in Group 1 as compared to Group 2 (P < 0.05) in our study. Srinivasan et al. report no difference in the onset of akinesia in the two groups. A study by Zahl et al. and Jordan A reports faster anesthesia and akinesia with pH buffered anesthetic solution. However, in this study, both groups had hyaluronidase as the composition of an anesthetic mixture.
In our study, grading of akinesia and anesthesia was statistically significant in the two groups (P < 0.05). The grade of akinesia was better in Group 1, i.e., with hyaluronidase. In the study by Gupta and Kapoor, there was no statistical difference in the grading of akinesia and anesthesia in two groups.
In our study, the VAS score on drop instillation was comparable in two groups (P > 0.05), but the VAS of pain on peribulbar injection was found to be statistically significant (P < 0.05). The pain perception was less in cases with sodium bicarbonate in anesthetic solution. Gupta et al. in their study found that the addition of sodium bicarbonate in local anesthetics reduces pain and decreases the onset of anesthesia similar to our study. They also used VAS to quantify pain perception in their participants. Local anesthetic solutions available commercially have an acidic pH to increase their shelf life by maximizing water solubility and chemical stability. Before injecting, an alkali can be added to raise the pH toward physiological pH. This process is called alkalinization. This can also result in less stinging pain on injecting the solution. A systematic review by Hanna et al. found that the pain of intradermal injection of alkalinized local anesthetic was less as compared to unbuffered local anesthetic. Another meta-analysis was done by Kattan S et al. concluded that patients receiving buffered local anesthetic solutions experienced less pain. Their study revealed that buffering local anesthetic has a 2.29 (odds ratio) times greater chance of achieving a successful block as compared to nonbuffered solution.
No study is there where sodium bicarbonate and hyaluronidase are compared to see the effect on pain perception in the peribulbar block in cataract surgery.
There is an ever-increasing demand for hyaluronidase causing a shortage in its supply. In our district, we had availability issues of hyaluronidase, but sodium bicarbonate was freely available at a lower cost than hyaluronidase which even required cold chain maintenance in some of the brands.
| Conclusion|| |
Our study has confirmed that sodium bicarbonate reduces pain on injection in peribulbar anesthesia and results in a quicker onset of anesthesia although the degree of akinesia achieved is more with hyaluronidase. Hence, in future, the addition of sodium bicarbonate can be an alternative where topical anesthesia is not feasible, and the motive is better patient comfort with respect to pain on injection.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]