Preoperative topical lidocaine in pediatric squint surgeries: a randomized clinical trial

Abeer S Salem; Dina Moustafa Mohamed; Iman S Aboul Fetouh; Rehab S Khattab; Sara R Mahmoud

doi:10.4103/roaic.roaic_51_22

ORIGINAL ARTICLE

Year : 2022 | Volume : 9 | Issue : 4 | Page : 365-369

Preoperative topical lidocaine in pediatric squint surgeries: a randomized clinical trial

Abeer S Salem, Dina Moustafa Mohamed, Iman S Aboul Fetouh, Rehab S Khattab, Sara R Mahmoud
Department of Anesthesia, Research Institute of Ophthalmology, Giza, Egypt

Date of Submission	11-Sep-2022
Date of Decision	14-Oct-2022
Date of Acceptance	26-Oct-2022
Date of Web Publication	29-Dec-2022

Correspondence Address:
MD Abeer S Salem
Department of Anesthesia, Research Institute of Ophthalmology, 2 El Ahram Street, Giza, 12557
Egypt

Source of Support: None, Conflict of Interest: None

Check

DOI: 10.4103/roaic.roaic_51_22

Abstract

Aims To assess the safety and efficacy of lidocaine gel 2% used in pediatric squint surgeries to prevent the oculocardiac reflex intraoperatively and reduce postoperative pain and agitation.
Settings and design This single-blinded, randomized trial was carried out at the Research Institute of Ophthalmology, Egypt.
Patients and methods Forty-eight children (2–13 years old) of both sexes scheduled for squint surgeries were randomly allocated into two groups (24 patients each): the lidocaine gel group and the control group. In the experimental group, we applied lidocaine gel 2% abundantly below both eyelids of the surgical eye for at least 3 min before surgical incision, while nothing was applied to patients in the control group. Patients were monitored intraoperatively and postoperatively, and the outcomes were recorded.
Results There was a lower median postoperative face, leg, activity, cry, and consolability scale in the lidocaine gel group (3.0, interquartile range=2.5–5.0) than in the control group (4.0, interquartile range=1.5–7.0) with no significant difference (P=0.770). The incidence of bradycardia was lower with lidocaine gel 2% use (16.7%) compared with the control group (41.7%), but this difference was not statistically significant (P=0.057). We found no complications except for two patients in the control group who had fever and flushing due to atropine administration.
Conclusion Application of lidocaine gel 2% below both lids of the surgical eye in pediatric squint surgery under general anesthesia is safe with no observed systemic side effects. However, it has no adjuvant effects in reducing postoperative pain and agitation or preventing intraoperative oculocardiac reflex.

Keywords: child, lidocaine, oculocardiac reflex, postoperative pain, strabismus

How to cite this article:
Salem AS, Mohamed DM, Aboul Fetouh IS, Khattab RS, Mahmoud SR. Preoperative topical lidocaine in pediatric squint surgeries: a randomized clinical trial. Res Opin Anesth Intensive Care 2022;9:365-9

How to cite this URL:
Salem AS, Mohamed DM, Aboul Fetouh IS, Khattab RS, Mahmoud SR. Preoperative topical lidocaine in pediatric squint surgeries: a randomized clinical trial. Res Opin Anesth Intensive Care [serial online] 2022 [cited 2023 Mar 26];9:365-9. Available from: http://www.roaic.eg.net/text.asp?2022/9/4/365/365795

Introduction

Squint correction surgery is a very common eye operation in children [1]. It is usually associated with moderate intraoperative and postoperative pain, stimulation of the oculocardiac reflex (OCR), and postoperative nausea and vomiting [2].

In children, squint surgeries require general anesthesia in addition to various drugs including opioids, nonsteroidal anti-inflammatory drugs, and local anesthetics for effective pain control and perioperative analgesia [3].

The OCR is triggered by stimulation of any sensory branches of the trigeminal nerve around the orbit and specifically by traction on extraocular muscles. Intraoperative stimulation of the OCR usually results in mild-to-moderate sinus bradycardia; however, less than 10% of cases can develop other parasympathetic dysrhythmias such as A-V nodal, junctional rhythm, or even premature ventricular beats. Sometimes bradycardia is also accompanied by hypotension and apnea. The conveyed incidence of OCR in squint surgery fluctuates between 16 and 82% [4],[5].

Various anesthetic medications and anticholinergic premedication have been previously investigated to lower the occurrence of OCR. However, these attempts have not yet been found to be consistently effective [6].

Lidocaine 2% ophthalmic gel has been effectively used as an adjunct local anesthetic and analgesic during pediatric cataract surgery [7] and squint surgery in adults [8]. The gel formulation is highly viscid, with the potential advantage of increased contact time with the ocular surface and greater tissue penetration, which guarantees a sustained anesthetic effect [9].

Few earlier studies have evaluated the effectiveness of lidocaine 2% gel in pediatric squint surgery [10],[11],[12]. Therefore, this study was conducted to assess the safety and efficacy of lidocaine gel 2% used in pediatric squint surgeries to prevent OCR intraoperatively and reduce postoperative pain and agitation.

Patients and methods

Ethical considerations

The study protocol was approved by the Ethics Committee of the Research Institute of Ophthalmology, Egypt (14/3/2021). We obtained informed written consents from the patients’ guardians. The trial was registered at the clinicalTrials.gov (ID: NCT04859062). We intend to share the individual deidentified participants’ data. The data will be provided by the corresponding author on reasonable request, beginning 12 months and ending 36 months following article publication.

Study design, settings and duration

This randomized, single-blinded, controlled trial was conducted at the Research Institute of Ophthalmology, Egypt between August 1, 2021 and April 1, 2022.

Inclusion criteria

We included children (2–13 years old) of both sexes who were scheduled for squint surgeries.

Exclusion criteria

We excluded patients with a history of previous extraocular eye surgery (e.g. previous squint) or eye trauma.

Randomization and blinding

Forty-eight children were randomly allocated into two groups (24 patients each): the lidocaine gel group and the control group. The sequentially numbered, opaque, sealed envelope method was used for randomization and allocation concealment of the study participants [13]. The opaque envelopes were impermeable to light and the allocation sequence was concealed from the investigator who assessed and enrolled participants. Each patient was first assessed and enrolled based on the eligibility criteria of the study. The corresponding envelope was opened only after the enrolled participant completed all baseline assessments and it was time to allocate the intervention. Only the study participants were masked.

Intervention

In the operation room, we started inhalational induction of anesthesia with sevoflurane till the patient is deeply anesthetized. In the experimental group, we applied lidocaine gel 2% 1 ml below each eyelid of the surgical eye for at least 3 min before surgical incision and not longer than 10 min (as the duration of action of lidocaine gel 2% is not more than 30 min), while nothing was applied to patients in the control group. ECG, pulse oximetry, capnography, and noninvasive blood pressure monitors were attached to the patient. We monitored the patient’s heart rate intraoperatively and documented bradycardia, if any (decrease in heart rate more than 20% of the baseline). Atropine (0.01 mg/kg) was considered if releasing the muscle traction was not enough to end the reflex. After recovery from anesthesia and in the postoperative anesthesia care unit, we assessed the patient’s postoperative pain and agitation using a 10-point scale face, leg, activity, cry, and consolability ranging from 0 to 10, where 0 is no pain and 10 is unbearable pain. In the postoperative anesthesia care unit, intervention using analgesic or sedative drugs were only used after full recovery (score 6) of the pediatric patients using Steward postanesthetic recovery score for proper assessment of pain. Patients were not covered during the assessment of activity.

Outcomes

The primary outcomes were postoperative pain and the need for postoperative systemic analgesia. The secondary outcomes were the OCR intraoperatively and the need for intraoperative atropine as well as any complications.

Statistical analysis

All data were analyzed using the Statistical Package for Social Sciences (IBM SPSS Statistics), version 26 for Windows (IBM Corp., Armonk, N.Y., USA). Categorical data were presented as numbers and percentages and Pearson’s χ² was used to investigate the difference between the studied groups. Concerning continuous data, they were tested for normality by the Shapiro–Wilk test. Normally distributed continuous data were expressed as Mean±SD and the independent samples Student’s t test was applied, while nonnormally distributed data were expressed as median and interquartile range (IQR) (expressed as 25th–75th percentiles), and the Mann–Whitney U test was applied for group comparison. P value less than 0.05 was considered statistically significant.

Results

This study included 48 children who were scheduled for squint surgery. They were randomly allocated either to the lidocaine gel group (N=24) or the control group (N=24). All patients were monitored intraoperatively and postoperatively and were included in the analysis ([Figure 1]).

Figure 1 CONSORT flow diagram of the trial.

Click here to view

[Table 1] shows comparable means of age with no significant difference between both groups (6.6±2.7 vs. 5.5±2.7, P=0.200) as well as homogeneous sex distribution (P=0.149).

Table 1 Demographic characters of the studied groups

Click here to view

Concerning the efficacy of lidocaine gel 2%, [Table 2] demonstrates a lower median postoperative FLAAC scale in the lidocaine gel group (3.0, IQR=2.5–5.0) than in the control group (4.0, IQR=1.5–7.0), with no significant difference (P=0.770). The frequency of postoperative need for analgesia and sedation was also nonsignificantly lower in the lidocaine gel group (29.2%) than in the control group (37.5%). The incidence of bradycardia was lower with lidocaine gel 2% use (16.7%) than in the control group (41.7%), but this difference did not reach a significant level (P=0.057). As well, the need for atropine was nonsignificantly lower in the lidocaine gel group than in the control group (16.7 vs. 33.3%, respectively, P=0.182).

Table 2 Comparison between the studied groups regarding primary and secondary outcomes

Click here to view

We found no complications except for two patients in the control group who had fever and flushing due to atropine administration. They were managed with cold foments and paracetamol.

Discussion

Handling of the eye muscles is greater in squint surgery than in other eye surgeries and results in potentially more intraoperative and postoperative pain, with increased rates of OCR [14]. This study aimed to assess the safety and efficacy of lidocaine gel as a topical nerve blocker in children who underwent squint correction surgery.

This randomized clinical trial revealed that the topical use of lidocaine gel 2% after induction of general anesthesia in pediatric squint surgeries was safe with no observed systemic side effects, but it did not have adjuvant effects in reducing postoperative pain and agitation or preventing intraoperative OCR in comparison to the control group.

The analgesic effect of lidocaine was previously shown by Gopal et al. [15], who effectively performed strabismus surgery under topical anesthesia using proparacaine and lignocaine hydrochloride gel with no incidence of intraoperative pain and with high patient and surgeon satisfaction.

In the current study, the use of lidocaine gel 2% once for at least 3 min before the surgical incision was associated with lower postoperative pain and agitation than in the control group, but the detected difference did not reach a statistically significant level. As well, the need for postoperative analgesia and sedation was nonsignificantly lower in the lidocaine gel group (29.2%) than in the control group (37.5%). In contrast, a previous randomized clinical trial included children having elective squint surgery and demonstrated a significantly improved perioperative analgesia associated with a reduced requirement for intraoperative fentanyl and postoperative ibuprofen with lidocaine 2% gel used in comparison to proparacaine 0.5% eye drops [12].

During strabismus surgery, both anesthesiologists and ophthalmic surgeons are concerned about the OCR phenomenon, and they closely monitor potential signs of the OCR and attempt to prevent its occurrence. Retrobulbar block, premedication with anticholinergics, and gentle tension during muscle traction have been proposed to reduce the incidence of OCR [16],[17],[18].

In the present study, lidocaine 2% gel did not show a significant effect in lowering the incidence of bradycardia or the need for atropine. Previous studies on the role of lidocaine gel 2% in reducing OCR incidence revealed inconsistent results. A former study investigated the effect of topical lignocaine applied to the eye muscles during pediatric squint surgery of the medial rectus and revealed a significant reduction in OCR incidence [11]. Another study evaluated the efficacy of topical xylocaine compared with placebo in retinal and strabismus surgeries and also reported a significant reduction in OCR occurrence [10]. However, Sinha et al. [12] noticed the absence of differences in the incidence and severity of OCR with a single application of lidocaine 2% gel compared with proparacaine 0.5% eye drops in children who underwent elective squint surgery. A more recent study compared tetracaine eye drops to placebo in squint surgery and highlighted a significantly reduced incidence and severity of OCR only during the muscle-incising stage, but this effect was not significant during the release phase [19].

The contradictory results might be explained in the light of the factors that influence the occurrence of OCR. It has been reported that maintenance of spontaneous respiration during surgery modulates is associated with a higher level of sympathetic activity that offsets the parasympathetic reflex [20]. In addition, negative intrathoracic pressure during spontaneous inspiration causes a slight increase in the heart rate because of vagal withdrawal and lung hyperinflation [21]. Furthermore, it has been shown that OCR incidence is not influenced by the depth of anesthesia [5]. Thus, lidocaine-induced additive nerve block did not show a significant effect.

This study is limited by being single-blinded besides the small sample size that reduces the chance of detecting a true effect.

Conclusion

Application of lidocaine gel 2% below both lids of the surgical eye in pediatric squint surgery under general anesthesia is safe with no observed systemic side effects. However, it has no adjuvant effects in reducing postoperative pain and agitation or preventing intraoperative OCR.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1.	Schuster AK, Elflein HM, Pokora R, Schlaud M, Baumgarten F, Urschitz M. Health-related quality of life and mental health in children and adolescents with strabismus − results of the representative population-based survey KiGGS. J Health Qual Life Outcomes 2019; 17:1–8.
2.	Ducloyer JB, Couret C, Magne C, Lejus-Bourdeau C, Weber M, Le Meur G et al. Prospective evaluation of anesthetic protocols during pediatric ophthalmic surgery. Eur J Ophthalmol 2019; 29:606–614.
3.	Mehrotra S. Postoperative anaesthetic concerns in children: postoperative pain, emergence delirium and postoperative nausea and vomiting. Indian J Anaesth 2019; 63:763–770. [PUBMED] [Full text]
4.	Arnold RW. The oculocardiac reflex: a review. Clin Ophthalmol 2021; 15:2693–2725.
5.	Shin SY, Kim MJ, Joo J. Oculocardiac reflex and oculorespiratory reflex during strabismus surgery under general anesthesia using the laryngeal mask airway with maintenance of spontaneous respiration: a retrospective study. J Int Med Res 2020; 48:300060520945158.
6.	Taghavi Gilani M, Sharifi M, Najaf Najafi M, Etemadi Mashhadi M. Oculocardiac reflex during strabismus surgery. J Rev Clin Med 2016; 3:4–7.
7.	Reddy AJ, Dang A, Dao AA, Arakji G, Cherian J, Brahmbhatt H. A substantive narrative review on the usage of lidocaine in cataract surgery. Cureus 2021; 13:e19138.
8.	Hakim OM, El-Hag YG, Haikal MA. Strabismus surgery under augmented topical anesthesia. J Am Assoc Pediatr Ophthalmol Strabismus 2005; 9:279–284.
9.	Liu B, Ding L, Xu X, Lin H, Sun C, You L. Ocular and systemic pharmacokinetics of lidocaine hydrochloride ophthalmic gel in rabbits after topical ocular administration. Eur J Drug Metab Pharmacokinet 2015; 40:409–415.
10.	Ruta U, Gerding H, Möllhoff T. Effect of locally applied lidocaine on expression of the oculocardiac reflex. Ophthalmologe 1997; 94:354–359.
11.	Ruta U, Möllhoff T, Markodimitrakis H, Brodner G. Attenuation of the oculocardiac reflex after topically applied lignocaine during surgery for strabismus in children. Eur J Anaesthesiol 1996; 13:11–15.
12.	Sinha R, Chandralekha , Batra M, Ray BR, Mohan VK, Saxena R. A randomised comparison of lidocaine 2% gel and proparacaine 0.5% eye drops in paediatric squint surgery. Anaesthesia 2013; 68:747–752.
13.	Doig GS, Simpson F, Delaney A. A review of the true methodological quality of nutritional support trials conducted in the critically ill: time for improvement. Anesth Analg 2005; 100:527–533.
14.	Chua AW, Chua MJ, Leung H, Kam PC. Anaesthetic considerations for strabismus surgery in children and adults. Anaesth Intensive Care 2020; 48:277–288.
15.	Gopal KSS, Kelkar JA, Arora ER. Our experience with strabismus surgery under topical anesthesia performed at a tertiary eye care center. Indian J Ophthalmol 2018; 66:342–343. [PUBMED] [Full text]
16.	Arnold RW, Bond AN, McCall M, Lunoe L. The oculocardiac reflex and depth of anesthesia measured by brain wave. BMC Anesthesiol 2019; 19:36.
17.	Braun U, Feise J, Mühlendyck H. Is there a cholinergic and an adrenergic phase of the oculocardiac reflex during strabismus surgery? Acta Anaesthesiol Scand 1993; 37:390–395.
18.	Gupta N, Kumar R, Kumar S, Sehgal R, Sharma KR. A prospective randomised double blind study to evaluate the effect of peribulbar block or topical application of local anaesthesia combined with general anaesthesia on intra-operative and postoperative complications during paediatric strabismus surgery. Anaesthesia 2007; 62:1110–1113.
19.	Rahimi Varposhti M, Moradi Farsani D, Ghadimi K, Asadi M. Reduction of oculocardiac reflex with Tetracaine eye drop in strabismus surgery. Strabismus 2019; 27:1–5.
20.	Narkiewicz K, van de Borne P, Montano N, Hering D, Kara T, Somers VK. Sympathetic neural outflow and chemoreflex sensitivity are related to spontaneous breathing rate in normal men. Hypertension 2006; 47:51–55.
21.	Shekerdemian L, Bohn D. Cardiovascular effects of mechanical ventilation. Arch Dis Child 1999; 80:475–480.