Anesthetic Techniques and Postoperative Emesis in Pediatric Strabismus Surgery:

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.

Reducing postoperative pain in children undergoing strabismus surgery: From bundle implementation to clinical decision support tools

BACKGROUND

Postoperative pain is a significant cause of morbidity in pediatric anesthesia, which can result in delayed discharge and unplanned hospital admission. Children undergoing strabismus surgery are known to be a particularly high-risk group for postoperative pain.

AIM

The aim of this project was to reduce the incidence of moderate to severe postoperative pain by 25% over a period of 12 months in children undergoing strabismus surgery.

METHODS

This was a multidisciplinary quality improvement project using the Institute for Healthcare Improvement model for improvement and iterative Plan-Do-Study-Act cycles. Baseline data from one hundred patients were collected retrospectively from patient records. Subsequently, iterative interventions introduced comprised: a perioperative bundle (comprising preoperative acetaminophen, intraoperative dexamethasone and ketorolac, a long-acting opioid, and two anti-emetics), email reminders, dissemination of results at departmental rounds, and an intraoperative clinical decision aide. Postoperative pain data were collected as an outcome measure, and length of stay in PACU was monitored as a balancing measure. Statistical process control charts were constructed to monitor bundle compliance and incidence of postoperative pain in the postanesthesia care unit.

RESULTS

Postoperative pain and bundle compliance data were collected for 1127 children in total. Baseline mean monthly incidence of moderate to severe postoperative pain was 47.3%. By the conclusion of this project, the incidence of postoperative pain decreased to 21%. Concurrently, mean bundle compliance increased to 78.7%. Mean length of PACU stay for baseline audit patients was 72.5 min compared with 70 min for patients after the introduction of the strabismus macro (November 2018-April 2019, n 91) (mean difference, 2.5; 95% CI, -3.86 to 8.86; P = .439).

CONCLUSION

Through the implementation and adoption of an evidence-based bundle of care, we successfully decreased the incidence of moderate to severe postoperative pain for children undergoing strabismus repair. We demonstrated that combining nudge theory with QI methodology can be an effective means of delivering positive results in quality improvement projects.

A Randomized Controlled Trial to Compare Pain Medications in Children Undergoing Strabismus Surgery

PURPOSE

The purpose of this study was to investigate optimal intraoperative combinations of analgesia for children undergoing strabismus surgery.

DESIGN

A randomized controlled trial was employed to compare the difference in pain after administration of hydromorphone versus fentanyl.

METHODS

Participants were randomly assigned to either arm of the study. Pain was measured by the revised Faces, Legs, Activity, Cry, and Consolability Scale (rFLACC) tool postoperatively, and the parent was asked about the presence or absence of pain after discharge.

FINDINGS

A total of 135 children were included in the study. The rFLACC pain score was found to be significantly higher postoperatively among patients receiving fentanyl (P = .011). Pain after discharge was reported more often among patients who received fentanyl (P < .001).

CONCLUSIONS

Results of this study can be used to change practice to minimize the pain levels both postoperatively and after discharge for children undergoing strabismus surgery.

Contact topical anesthesia for strabismus surgery in adult patients

OBJECTIVE

To analyze the effectiveness and usefulness of contact topical anesthesia in strabismus surgery in adult patients.

MATERIAL AND METHODS

A prospective study was conducted on 20 patients undergoing strabismus surgery using contact topical anesthesia and sedation with remifentanil. The intensity of pain was recorded using a numeric pain rating scale at the time of anesthesia implementation, during the surgical procedure, 30 min afterwards, and during the first postoperative day. The incidence of oculocardiac reflex, postoperative nausea and vomiting, corneal ulcers, patient satisfaction (numerically from 0 to 10) and the degree of residual ocular deviation were also assessed.

RESULTS

The operation was performed successfully in all patients. Average pain intensity was 1.40 ± 1.73 during anesthesia implementation, 4.20 ± 2.57 during the surgical procedure, 2.50 ± 2.54 30 min after surgery, and 3.55 ± 2.89 during the first postoperative day. Oculocardiac reflex was observed in 7 patients (35%), postoperative nausea and vomiting in 4 (20%), and corneal ulcer in 4 (20%). The patient satisfaction was 9.53 ± 2.51. More than two-thirds (70%) of patients had a residual ocular deviation less than 10 prism diopters.

CONCLUSIONS

Contact topical anesthesia is a safe and effective alternative for strabismus surgery in adult patients. Contact topical anesthesia provides adequate pain control, lower incidence of postoperative nausea and vomiting and oculocardiac reflex, and optimal setting of ocular alignment.

Comparison of the effects of dexmedetomidine, ketamine, and placebo on emergence agitation after strabismus surgery in children

BACKGROUND

Children undergoing strabismus surgery under sevoflurane anesthesia often experience emergence agitation (EA) and postoperative vomiting (POV). This study compared the effects of intraoperative dexmedetomidine, ketamine, and placebo on postoperative EA and POV.

METHODS

Eighty-four children (aged two to seven years) undergoing elective strabismus surgery under sevoflurane anesthesia were randomly assigned to one of three groups (n = 28 each). Intraoperatively, the placebo, dexmedetomidine, and ketamine groups received normal saline, dexmedetomidine 1 μg·kg(-1) iv plus a 1 μg·kg(-1)·hr(-1) infusion, and ketamine 1 mg·kg(-1) iv plus a 1 mg·kg(-1)·hr(-1) infusion, respectively. Agitation scores (Pediatric Anesthesia Emergence Delirium [PAED] scale) and POV were assessed in the postanesthetic care unit (PACU) and for 24 hr on the ward. Pain scores and times to laryngeal mask airway (LMA™) removal, resumption of mental orientation, and discharge from the PACU were also assessed.

RESULTS

Seventy-eight children completed the study. Peak PAED scores for EA were lower in the dexmedetomidine (P < 0.001) and ketamine (P = 0.002) groups than in the placebo group. Incidence of POV was lower in the dexmedetomidine group (15%) than in the ketamine (44%; P = 0.02) or placebo (45.8%; P = 0.02) groups. Pain scores on the ward were lower in the dexmedetomidine (P < 0.001) and ketamine (P < 0.001) groups than in the placebo group. Time to LMA removal was similar in all groups. Time for resumption of mental orientation and time to discharge from PACU were longer in the dexmedetomidine and ketamine groups than in the placebo group.

CONCLUSIONS

Dexmedetomidine and ketamine appear to prevent postoperative agitation and pain after sevoflurane anesthesia for pediatric strabismus surgery. Dexmedetomidine also prevents POV.

Dexmedetomidine use during strabismus surgery in agitated children

OBJECTIVE

We aimed to investigate the effects of dexmedetomidine premedication before intravenous infusion of ketamine in agitated children undergoing strabismus surgery.

SUBJECTS AND METHODS

We enrolled 60 agitated pediatric patients, aged 4.5-11 years. The patients were randomly allocated to one of two anesthesia regimens. Group D patients were premedicated with a single dose of intravenous dexmedetomidine 0.5 μg/kg whereas group P patients received a placebo. Patients in both groups were administered intravenous ketamine 1 mg/kg i.v. over 1 min followed by a continuous infusion of ketamine 1-3 mg/kg/h i.v. (n = 30). Patients were intubated after receiving fentanyl 1 μg/kg and rocuronium bromide 0.5 mg/kg.

RESULTS

21 (70%) patients in group D did not show the oculocardiac reflex (OCR) versus 7 (23%) in group P (p = 0.0006). The preoperative and postoperative agitation scores (p = 0.0001 and p = 0.03, respectively), the score on the Faces Pain Scale during awakening [3.0 (interquartile range, IQR 2.0-4.0) in group D and 0.0 (IQR 1.0-2.25) in group P] (p = 0.001) and at the 60th postoperative minute [IQR 2.0 (1.5-3.0) in group D and 2.0 (IQR 1.5-3.0) in group P] (p = 0.004), sore throat (26.6% in group D and 60% in group P) (p = 0.01) and analgesic requirement (20% in group D and 53% in group P) (p = 0.01) in group P were significantly higher than in group D. The Ramsay Sedation Score (RSS) in group D was significantly higher than in group P during awakening [2.0 (2.0-2.0) in group D and 4.5 (4.0-5.0) in group P] (p = 0.0001).

CONCLUSION

Dexmedetomidine premedication followed by intravenous infusion of ketamine was effective in decreasing OCR, agitation, pain, analgesic requirement in agitated children undergoing strabismus surgery.

Anesthetic management for pediatric strabismus surgery: Continuing professional development

PURPOSE

Strabismus surgery is one of the most common pediatric ophthalmic procedures. The purpose of this continuing professional development module is to update physicians on the anesthetic considerations of pediatric patients undergoing strabismus surgery.

PRINCIPAL FINDINGS

The preoperative assessment is important, as patients undergoing strabismus surgery may have an associated neuromuscular disorder, congenital syndrome, or cardiac disease. Malignant hyperthermia is no longer considered as being an issue associated with strabismus. The laryngeal mask airway is used frequently and has been shown as being associated with a low incidence of complications in strabismus surgery. The anesthesia technique can be adapted to decrease the incidence of the oculocardiac reflex and the oculorespiratory reflex, and the use of anticholinergic prophylaxis remains debatable. Since patients are at high risk for postoperative nausea and vomiting (PONV), combination anti-emetic therapy is recommended using dexamethasone and ondansetron. Metoclopramide was not found to provide additional benefit when combined with other anti-emetics. Droperidol is effective, but there remains a black box warning for dysrhythmias. Effective analgesics in this patient population include acetaminophen, nonsteroidal anti-inflammatory drugs, peribulbar blocks, and subtenon blocks. Topical tetracaine drops have demonstrated mixed results, and topical nonsteroidal anti-inflammatory drops were found not to be effective. The use of opioids should be minimized due to the increased incidence of PONV.

CONCLUSIONS

To provide optimal care for the pediatric patient undergoing strabismus surgery, it is important to understand the unique anesthetic considerations for strabismus surgery and to appreciate how each decision regarding the anesthetic technique can alter these considerations.

Relation between middle ear pressure changes and postoperative nausea and vomiting in pediatric strabismus surgery

STUDY OBJECTIVE

To investigate the effects of tympanometric changes on the frequency of postoperative nausea and vomiting (PONV).

DESIGN

Prospective, observational study.

SETTING

University hospital.

PATIENTS

49 ASA physical status I, nonpremedicated children undergoing elective strabismus surgery.

INTERVENTIONS

Frequency of PONV was assessed at various time intervals (0-2, 2-6, and 6-24 hours) with a 4-point scale (0, no nausea; 1, nausea but no vomiting; 2, one episode of vomiting; 3, two or more episodes of vomiting), and correlation with tympanometric data was investigated.

MEASUREMENTS

Tympanogram was obtained before induction of standardized anesthesia and after full recovery. Fourteen (28.6%) patients had nausea, and 10 (20.4%) patients vomited. The tympanic gradient, compliance, and pressure values were found to be significantly higher in postoperative measurements than their preoperative counterparts (P < 0.05). The volumes of both ears increased postoperatively, but these differences were not statistically significant (P > 0.05). Changes in middle ear pressure, volume, compliance, and gradient did not correlate with PONV (P > 0.05).

CONCLUSIONS

Gradient, compliance, volume, and pressure changes in middle ears were not found to be related to the frequency of nausea and vomiting after strabismus surgery.

Propofol–remifentanil-based anaesthesia vs. sevoflurane–fentanyl-based anaesthesia for immediate postoperative ophthalmic evaluation following strabismus surgery

BACKGROUND AND OBJECTIVE

Following strabismus surgery, immediate postoperative ophthalmic evaluation may be desired. Thus, an anaesthetic technique allowing rapid recovery of ocular motility is required. Saccadic eye movements is a biophysical monitor of ocular motility and may be used to assess recovery from anaesthesia. The aim of this study is to compare the time to the recovery of saccadic eye movements in patients, following one of two anaesthetic techniques: Propofol-remifentanil-based anaesthesia vs. sevoflurane-fentanyl-based anaesthesia.

METHODS

Fifty adult patients undergoing strabismus surgery were randomly assigned to one of two groups: patients in Group R received induction and maintenance of anaesthesia with propofol and remifentanil, while patients in Group S received induction of anaesthesia with propofol and fentanyl and maintenance of anaesthesia with sevoflurane. Recovery from anaesthesia was measured from the time all anaesthetics were turned off and was assessed every 2 min. Recovery time was attained when patients were able to generate brisk saccadic eye movements. At recovery time, the ophthalmic evaluation was started.

RESULTS

The mean recovery time of saccadic eye movements was significantly shorter in the Group R when compared to the Group S (12.1 +/- 4.3 min vs. 21.5 +/- 4.7 min, respectively, P < 0.0001). More patients in Group S experienced nausea and vomiting postoperatively as compared to Group R (9/25 vs. 2/25, respectively, P = 0.037).

CONCLUSIONS

Propofol-remifentanil-based anaesthesia may be a useful technique in strabismus surgery when immediate postoperative ophthalmic evaluation is desired. When compared to sevoflurane maintenance of anaesthesia, it allows for a more rapid recovery from anaesthesia as judged by recovery of saccadic eye movements and a decreased incidence of postoperative nausea and vomiting.