Retrobulbar Block in Pediatric Vitreoretinal Surgery Eliminates the Need for Intraoperative Fentanyl and Postoperative Analgesia: A Randomized Controlled Study

[Different anesthesia management in preterm infants undergoing surgeries for retinopathy of prematurity: A retrospective study]

OBJECTIVE

To evaluate the effect of different anesthesia management on clinical outcomes in former prematurely born infants undergoing surgeries for retinopathy of prematurity (ROP).

METHODS

In this retrospective study, electronic medical record database was searched for all former prematurely born infants (gestational age < 37 weeks and post conceptual age < 60 weeks) who received ROP surgery under inhalational general anesthesia between November 2016 and October 2018. The patients were divided into two groups based on anesthesia management: laryngeal mask airway (LMA) insertion without intravenous muscle relaxant injection and with pressure support ventilation (LMA group) or airway secured with endotracheal tube (ETT) with intravenous muscle relaxant injection and pressure controlled ventilation (ETT group). Primary outcomes included perioperative adverse events and complications. Extubation time and length of stay after surgery were also recorded.

RESULTS

Sixty eight preterm infants in the LMA group and 100 preterm infants in the ETT group were included. The incidence of adverse events during surgery (including airway management change and desaturation) was similar in LMA group and ETT group (4.4% vs. 1.0%, P =0.364). During the early recovery period after surgery, the incidence of difficult extubation (extubation time >30 min) was significantly lower in LMA group compared with ETT group (4.4% vs.15.0%, RR=0.262, 95%CI:0.073－0.942, P=0.029). The incidence of respiratory events was similar between the two groups (20.6% vs. 27.0%, P =0.342). However, the incidence of apnea was significantly lower in the LMA group than in the ETT group (5.9% vs.19.0%, RR=0.266, 95%CI: 0.086－0.822, P =0.015). No significant difference was observed between the LMA group and ETT group in incidences of cardiovascular events (0% vs. 1.0%, P =1.000) and unplanned admission to neonatal intensive care unit (5.9% vs. 7.0%, P=0.774). No airway spasm, re-intubation, aspiration or regurgitation was observed during early recovery. During late recovery after returning to ward, the incidence of adverse events was also similar between the two groups (0% vs. 2.0%, P =0.241). The median (IQR) extubation time was 6 (5, 10) min in LMA group and 10 (6, 19) min in ETT group (P < 0.001). The median length of stay after surgery was significantly shortened in LMA group compared with ETT group [20 (17, 22) hours vs. 22 (17, 68) hours, P =0.002].

CONCLUSION

Compared with endotracheal intubation with intravenous muscle relaxant injection, laryngeal mask airway insertion without muscle relaxant could achieve an early extubation, and reduce the incidence of apnea during early recovery period in former prematurely born infants undergoing ROP surgery.

Comparative Study of Retrobulbar Block versus Ketamine Infusion during Eye Enucleation/Evisceration (Randomized Controlled Trial)

Background

The aim of this study is to compare the safety and efficacy of retrobulbar block versus intraoperative ketamine infusion in eye enucleation or evisceration under general anesthesia.

Materials and Methods

Forty-five patients belonging to American Society of Anesthesiologists Physical Status I and II undergoing eye enucleation or evisceration were randomly allocated to three equal groups (15 patients each). General anesthesia was used as the standardized technique in all patients. Group R received a single retrobulbar injection, Group K received intravenous ketamine infusion, and Group C received normal saline with the same rate of ketamine infusion. Intraoperative heart rate and mean arterial pressure, recovery time, postoperative pain score, time to first rescue analgesic, number of patients who required rescue analgesia, and any adverse events were reported.

Results

Postoperative pain Visual Analog Scale was significantly lower in R and K groups in comparison to the C group and was significantly higher in K than R group at 3, 6, 12, and 24 h. In addition, the time to first rescue analgesic was significantly longer in R group (429 ± 54 min) than that in K group (272 ± 34 min), but compared to both groups, it was longer in C group (52 ± 7 min). In K group, the recovery time was longer with higher sedation score in comparison to the other two groups.

Conclusions

Single retrobulbar injection and low-dose ketamine infusion are safe and effective when used as adjuvants to general anesthesia, but retrobulbar block provides better control of postoperative pain with prolonged time to first rescue analgesic and reduced analgesic consumption.

Regional Anesthesia for Pediatric Ophthalmic Surgery: A Review of the Literature

Ophthalmic pediatric regional anesthesia has been widely described, but infrequently used. This review summarizes the available evidence supporting the use of conduction anesthesia in pediatric ophthalmic surgery. Key anatomic differences in axial length, intraocular pressure, and available orbital space between young children and adults impact conduct of ophthalmic regional anesthesia. The eye is near adult size at birth and completes its growth rapidly while the orbit does not. This results in significantly diminished extraocular orbital volumes for local anesthetic deposition. Needle-based blocks are categorized by relation of the needle to the extraocular muscle cone (ie, intraconal or extraconal) and in the cannula-based block, by description of the potential space deep to the Tenon capsule. In children, blocks are placed after induction of anesthesia by a pediatric anesthesiologist or ophthalmologist, via anatomic landmarks or under ultrasonography. Ocular conduction anesthesia confers several advantages for eye surgery including analgesia, akinesia, ablation of the oculocardiac reflex, and reduction of postoperative nausea and vomiting. Short (16 mm), blunt-tip needles are preferred because of altered globe-to-orbit ratios in children. Soft-tip cannulae of varying length have been demonstrated as safe in sub-Tenon blockade. Ultrasound technology facilitates direct, real-time visualization of needle position and local anesthetic spread and reduces inadvertent intraconal needle placement. The developing eye is vulnerable to thermal and mechanical insults, so ocular-rated transducers are mandated. The adjuvant hyaluronidase improves ocular akinesia, decreases local anesthetic dosage requirements, and improves initial block success; meanwhile, dexmedetomidine increases local anesthetic potency and prolongs duration of analgesia without an increase in adverse events. Intraconal blockade is a relative contraindication in neonates and infants, retinoblastoma surgery, and in the presence of posterior staphylomas and buphthalmos. Specific considerations include pertinent pediatric ophthalmologic topics, block placement in the syndromic child, and potential adverse effects associated with each technique. Recommendations based on our experience at a busy academic ophthalmologic tertiary referral center are provided.

Effect of pterygopalatine blockade on perioperative stress and inflammatory outcomes following paediatric cataract surgery

BACKGROUND

General anesthesia is required to perform pediatric cataract surgery. To reduce severity of surgical intervention and postoperative complications, regional techniques have been concomitantly used. The traditional regional ophthalmic techniques are retrobulbar, peribulbar and sub-Tenon blocks, which present some technical difficulties and associated complication risks. The pterygopalatine blockade has been exempt of many of these concerns as it is performed out of the orbit. The purpose of this study was to compare the analgesic and anti-inflammatory effects of the pterygopalatine blockade with retrobulbar block in children undergoing elective congenital cataract surgery.

METHODS

After approval of ethics committee and informed consents, patients were enrolled to the study to have either ultrasound-guided pterygopalatine block (group P) or retrobulbar block (group R), with 2 mL lidocaine 2% and 1 mL ropivacaine 0.5%. Hemodynamic monitoring was recorded throughout the perioperative period. Cortisol level and oxidation-reduction status were assessed before and after surgery. Pain and inflammatory response (Tyndall effect, corneal syndrome and edema) were assessed on the first postoperative day.

RESULTS

Comparative analysis demonstrated a decrease in cortisol of 123.24% (p˂0.05) and an increase in the redox coefficient of 37.7% (p˂0.05) in group P. Pain intensity was significantly higher in group R until the 16th postoperative hour. The corneal syndrome in patients in group P and group R was noted by 7.6% and in 32.1%, respectively (p˂0.05).

CONCLUSION

The use of the pterygopalatine blockade as a component of anesthesia in pediatric cataract surgery allows reduction of the severity of surgical stress during surgical intervention, providing intraoperative hemodynamic stability and prolonged analgesia.

Low Body Weight Predicted Bradycardia and Desaturation in Retinopathy of Prematurity Surgeries: A Retrospective Cohort Study

Background: As a leading cause of childhood blindness, the epidemic of retinopathy of prematurity (ROP) in China is characterized by advanced stage of ROP in more mature infants than those in the West. More advanced stage of disease necessitates more complicated surgical procedures and consequently exposure to general anesthesia. These ex-prematurely born infants are at risk of developing desaturation especially after surgery under general anesthesia. Physical status, anesthetic management and surgical profile are three main facets of perioperative setting and need to be investigated to identify useful predictors for perioperative adverse events in this population of fragile infants. Methods: In this retrospective cohort study, we enrolled all infants undergoing ROP surgeries at Peking University People's Hospital, Beijing, China from November 1, 2016 to October 31, 2017. Physical status, anesthesia and surgical management were analyzed by exploratory factor analysis and component matrix to explore risk factors for adverse events. Results: During the 12 months, 267 cases were included, among whom 61 infants underwent two surgeries required by their ophthalmological conditions. The median postconceptual age at the time of surgery was 46 (40, 53) weeks, and median body weight was 4.0 (3.0, 6.5) kg. None of the infants was dependent on caffeine, oxygen or ventilator before surgery. Bradycardia (29/267, 10.9%) and postoperative desaturation (34/267, 13.4%) were identified as major cardiac and respiratory adverse events. Preoperative atropine, intubation and bigger body weight would prevent patients suffering from bradycardia. Infants with a body weight less than 3.15 kg had a significantly higher chance of desaturation and neonatal intensive care unit admission after ROP surgeries than those who weighed more than 3.15 kg (27.8 vs. 5.1%, OR 5.46 (95% CI 2.66-11.21), P = 0.000). Conclusion: This study found that preoperative atropine and intubation would prevent bradycardia and low body weight was a predictor for both bradycardia and postoperative desaturation in preterm infants undergoing ROP surgeries.

Retrobulbar dexmedetomidine in pediatric vitreoretinal surgery eliminates the need for intraoperative fentanyl and postoperative analgesia: A randomized controlled study

Purpose

This study evaluated the efficacy of retrobulbar ropivacaine plus dexmedetomidine compared with systemic fentanyl in pediatric vitreoretinal (VR) surgery.

Methods

This prospective double-blind, randomized controlled study was performed in 60 children undergoing VR surgery, age from 2 to 7 years. After general anesthesia, the following procedure was administrated: (1) retrobulbar block with 0.5% ropivacaine plus dexmedetomidine 1 μg/kg (group RD, n = 20), (2) retrobulbar block with 0.5% ropivacaine (group RB, n = 20), and (3) control group with general anesthesia only (group F, n = 20). Hemodynamics, postoperative pain scores, anesthetics consumption (remifentanil, propofol, fentanyl), and emergence agitation were recorded.

Results

Respiratory depression was observed in 7 of the 20 patients in group F after the laryngeal mask airway was removed in the operating room, compared with none in groups RD and RB. All patients in group F required intraoperative rescue fentanyl (average intraoperative fentanyl consumption, 26.6 ± 12.6 μg per patient). Some rescue fentanyl was required in group RB (three patients required one dose of rescue fentanyl). Patients in group RD required none. Groups RD and RB reported lower pain scores than group F at 4 h postoperatively (RD group: P < 0.001; RB group: P =0.002); pain scores in group RD were lower than that in group F at 6 h postoperatively (P < 0.001).

Conclusion

Retrobulbar dexmedetomidine as an adjuvant to ropivacaine is a safe and effective alternative to systemic fentanyl. This regimen provides better pain management, hemodynamic stability, and stress response suppression in pediatric VR surgery.