Study of Feasibility and Safety of Higher-Dose Dexmedetomidine in Special Outpatient Examination of Pediatric Ophthalmology

Postoperative complications and axial length growth after bilateral congenital cataract surgery: eyes with microphthalmos compared to a comparison group

PURPOSE

To investigate the postoperative clinical outcomes and axial length (AL) growth of infants with congenital cataracts and microphthalmos following first-stage cataract surgery.

DESIGN

Retrospective case-control study.

METHODS

Setting: Single centre. Infants with congenital cataract that met the inclusion criteria were classified into two groups: the microphthalmos and comparison groups. All infants underwent a thorough ophthalmologic examination before surgery, and one week, 1 month, 3 months, and every 3 months after surgery.

RESULTS

This study enrolled 21 infants (42 eyes) in the microphthalmos group and 29 infants (58 eyes) in the comparison group. More glaucoma-related adverse events were observed in the microphthalmos group (7 eyes, 16.7%) than in the comparison group (0 eyes, 0%) (p < 0.001). At each subsequent follow-up, the comparison group had a greater AL than the microphthalmos group (all p < 0.001), and AL growth was significantly higher in the comparison group than in the microphthalmos group (all p = 0.035). Visual acuity improvement in the microphthalmos group was similar to that of the comparison group.

CONCLUSION

Early surgical intervention improves visual function in infants with congenital cataracts and microphthalmos although with a higher incidence of glaucoma-related adverse events. After cataract removal, the AL growth of microphthalmic eyes is slower than that of normally developed eyes.

Dexmedetomidine alleviates olfactory cognitive dysfunction by promoting neurogenesis in the subventricular zone of hypoxic-ischemic neonatal rats

Background: Hypoxic-ischemic brain damage (HIBD) is the main cause of neurological dysfunction in neonates. Olfactory cognitive function is important for feeding, the ability to detect hazardous situations and social relationships. However, only a few studies have investigated olfactory cognitive dysfunction in neonates with HIBD; furthermore, the specific mechanisms involved are yet to be elucidated. It has been reported that neurogenesis in the subventricular zone (SVZ) is linked to olfactory cognitive function. Recently, dexmedetomidine (DEX) has been shown to provide neuroprotection in neonates following HIBD. In the present study, we investigated whether DEX could improve olfactory cognitive dysfunction in neonatal rats following HIBD and attempted to determine the underlying mechanisms.

Methods: We induced HIBD in rats using the Rice–Vannucci model, and DEX (25 μg/kg, i.p.) was administered immediately after the induction of HIBD. Next, we used triphenyl tetrazolium chloride (TTC) staining and the Zea-longa score to assess the success of modelling. The levels of BDNF, TNF-α, IL-1β and IL-6 were determined by western blotting. Immunofluorescence staining was used to detect microglial activation and microglial M1/M2 polarization as well as to evaluate the extent of neurogenesis in the SVZ. To evaluate the olfactory cognitive function, the rats in each group were raised until post-natal days 28–35; then, we performed the buried food test and the olfactory memory test.

Results: Analysis showed that HIBD induced significant brain infarction, neurological deficits, and olfactory cognitive dysfunction. Furthermore, we found that DEX treatment significantly improved olfactory cognitive dysfunction in rat pups with HIBD. DEX treatment also increased the number of newly formed neuroblasts (BrdU/DCX) and neurons (BrdU/NeuN) in the SVZ by increasing the expression of BDNF in rat pups with HIBD. Furthermore, analysis showed that the neurogenic effects of DEX were possibly related to the inhibition of inflammation and the promotion of M1 to M2 conversion in the microglia.

Conclusion: Based on the present findings, DEX treatment could improve olfactory cognitive dysfunction in neonatal rats with HIBD by promoting neurogenesis in the SVZ and enhancing the expression of BDNF in the microglia. It was possible associated that DEX inhibited neuroinflammation and promoted M1 to M2 conversion in the microglia.

Sedation with Intranasal Dexmedetomidine in the Pediatric Population for Auditory Brainstem Response Testing: Review of the Existing Literature

Background: Intranasal dexmedetomidine (IN DEX) is a relatively new sedative agent with supporting evidence on its efficacy and safety, which can be used for procedural sedation in children, and could have a major role in auditory brainstem response testing, especially in the case of non-cooperative children. The goal of this systematic review is to assess the role of IN DEX in ABR testing, evaluating the reported protocol, potential, and limits. Methods: We performed a comprehensive search strategy on PubMed, Scopus, and Google Scholar, including studies in English on the pediatric population, without time restrictions. Results: Six articles, published between 2016 and 2021, were included in the systematic review. Sedation effectiveness was high across the studies, except for one study; 3 μg/kg was the dosing most often used. A comparison group was present in three studies, with oral chloral hydrate as the drug of comparison. Adverse effects were rarely reported. Conclusion: This systematic review showed how IN DEX can represent an adequate sedative for children undergoing ABR testing; larger and more rigorous trials are warranted in order to recommend its systematic utilization.

Posterior Capsular Outcomes of Pediatric Cataract Surgery With In-The-Bag Intraocular Lens Implantation

AIM

To investigate the change of posterior capsular outcomes of pediatric cataract surgery with primary in-the-bag intraocular lens (IOL) implantation.

METHODS

We conducted a case series of pediatric cataract children who underwent cataract extraction with primary in-the-bag IOL implantation, posterior capsulorhexis or vitrectorhexis, and limited anterior vitrectomy at the Eye Hospital of Wenzhou Medical University between 2016 and 2019. Digital retro-illumination photographs of pediatric eyes were obtained at baseline and 6 months, 12 months, and the last visit postoperatively. Capsular outcomes of the posterior capsular opening area (PCOA) and lens reprolifration area at those time points were compared. Correlations between the PCOA and influential factors, such as age at surgery, axial growth, and follow-up duration, were analyzed. The study was registered at register.clinicaltrials.gov (NCT04803097).

RESULTS

Data of 23 patients (27 eyes) were used in the final analysis. During follow-up, the PCOA enlarged at a rate of 0.29-0.32 mm²/month during the first six months postoperatively and 0.05-0.08 mm²/month over the next 1-2 years. Six months postoperatively, the PCOA enlargement statistically and positively correlated with the follow-up duration and axial growth. The area of lens reprolifration was 0.46 ± 1.00 mm² at six months postoperatively and then remained stable.

CONCLUSION

The PCOA enlarged rapidly within the first six months after the pediatric cataract surgery with primary IOL implantation. Six months postoperatively, the enlargement of PCOA was positively correlated with follow-up duration and axial growth. Posterior capsulorhexis or capsulectomy should be performed with a diameter of 3.0 to 4.0 mm for good visual axis transparency and the protection of in-the-bag IOL.

Evaluation of Intranasal Dexmedetomidine as a Procedural Sedative for Ophthalmic Examination of Children With Glaucoma

PRECIS

This study evaluated 2 doses of intranasal dexmedetomidine (IND) (3.0 and 3.5 µg/kg) as a procedural sedative for postoperative examination of children with glaucoma. A dose of 3.5 µg/kg was more efficacious and obviated the need for repeated general anesthesia.

PURPOSE

This study was carried out to determine the safety and effective dose of IND as a procedural sedative for postoperative follow-up examinations after glaucoma surgery in children in place of repeated examination under anesthesia.

MATERIALS AND METHODS

In this prospective randomized double-blinded interventional study, consecutive children aged 6 months to 6 years were randomized to receive 3.0 and 3.5 µg/kg IND using a mucosal atomizer device in the preoperative area of the operating room, under continuous monitoring of vital signs. Intranasal midazolam 0.25 mg/kg was used as a rescue agent in case of inadequate sedation, and general anesthesia was administered in case of persistent failure. All infants underwent a complete anterior and posterior segment evaluation including intraocular pressure and corneal diameter measurements.

RESULTS

A total of 30 and 31 children aged 23.9±15.0 and 19.2±10.1 months, respectively, received 3.0 and 3.5 µg/kg IND. Adequate sedation was possible in 18 of 30 (60%) children receiving 3.0 µg/kg and 24 of 31 (77.4%) receiving 3.5 µg/kg IND alone (P=0.17). In combination with midazolam, successful sedations were 86.6% versus 100%, respectively (P=0.052). One patient in the 3.5 µg/kg group had ventricular arrhythmia, reversed with dextrose-saline infusion and injection glycopyrrolate.

CONCLUSIONS

IND appears to be a safe and effective procedural sedative for postoperative follow-up examinations of pediatric glaucoma patients at doses of 3 and 3.5 µg/kg. The dose of 3.5 µg/kg was successful in more children.

Intranasal Dexmedetomidine for Procedural Distress in Children: A Systematic Review

CONTEXT

Intranasal dexmedetomidine (IND) is an emerging agent for procedural distress in children.

OBJECTIVE

To explore the effectiveness of IND for procedural distress in children.

DATA SOURCES

We performed electronic searches of Medline (1946-2019), Embase (1980-2019), Google Scholar (2019), Cumulative Index to Nursing and Allied Health Literature (1981-2019), and Cochrane Central Register.

STUDY SELECTION

We included randomized trials of IND for procedures in children.

DATA EXTRACTION

Methodologic quality of evidence was evaluated by using the Cochrane Collaboration's risk of bias tool and the Grading of Recommendations Assessment, Development, and Evaluation system, respectively. The primary outcome was the proportion of participants with adequate sedation.

RESULTS

Among 19 trials (N = 2137), IND was superior to oral chloral hydrate (3 trials), oral midazolam (1 trial), intranasal midazolam (1 trial), and oral dexmedetomidine (1 trial). IND was equivalent to oral chloral hydrate (2 trials), intranasal midazolam (2 trials), and intranasal ketamine (3 trials). IND was inferior to oral ketamine and a combination of IND plus oral ketamine (1 trial). Higher doses of IND were superior to lower doses (4 trials). Adverse effects were reported in 67 of 727 (9.2%) participants in the IND versus 98 of 591 (16.6%) in the comparator group. There were no reports of adverse events requiring resuscitative measures.

LIMITATIONS

The adequacy of sedation was subjective, which possibly led to biased outcome reporting.

CONCLUSIONS

Given the methodologic limitations of included trials, IND is likely more effective at sedating children compared to oral chloral hydrate and oral midazolam. However, this must be weighed against the potential for adverse cardiovascular effects.