Stringent fasting guidelines and separation from parents make the perioperative period an anxious time for small children. Although the standard period of 8 hours of NPO status (fasting) for solid food and nonclear liquids is required, children may receive clear liquids 2 to 3 hours before surgery without increasing the risk of aspiration.¹ Adequate preoperative hydration with clear liquids decreases the incidence of intraoperative hypoglycemia, hypovolemia, and PONV. Parental separation and fears of pain and blindness after surgery can be effectively addressed with the preoperative interview and appropriate anxiolysis. Many institutions routinely use premedication for young children (between 10 months and 12 years of age) before ophthalmic procedures. Midazolam, 0.5 mg/kg (up to a maximum of 10 mg regardless of the patient’s actual weight), is given as an oral premedication 10 to 20 minutes prior to surgery to alleviate separation anxiety and ease the induction of general anesthesia. It may be given with apple juice, lemon-lime soda, and grape syrup or combined with an acetaminophen elixir or ibuprofen elixir.

Infants and children may be induced by either intravenous or inhalational techniques, but most general anesthetics in young children undergoing cataract surgery are done with an inhalational induction having the IV placed after the child is anesthetized. The important exception to this is the pediatric patient with a personal or family history of malignant hyperthermia where inhalational agents are contraindicated.

Sevoflurane is the induction agent of choice in children, because it possesses a minimally offensive odor and is less stimulating to the airway. General anesthesia may be maintained with sevoflurane, isoflurane, or desflurane in air and oxygen. Desflurane has been associated with increased airway irritability when used for induction and is used mainly for maintenance of general anesthesia. Nitrous oxide, traditionally used with volatile anesthetics, may increase PONV. The cause-and-effect relationship between nausea/vomiting and nitrous oxide remains controversial. Since ophthalmic procedures increase the risk of PONV, a mixture of air/oxygen or 100% oxygen can be used in place of nitrous oxide. Nitrous oxide may be used in conjunction with sevoflurane to speed the induction of general anesthesia and then be turned off once the child is past the excitement stage of induction.

Propofol is the intravenous induction agent of choice for cataract surgery in pediatric patients with preoperative intravenous access. Propofol is an isopropyl phenol that has a rapid onset and offset of action. Intravenous injection of a therapeutic dose of propofol produces hypnosis rapidly with minimal excitation and postoperative residual effects. It is also believed to have antiemetic properties. A small intravenous bolus dose of propofol is often used in older children prior to placing an airway device, either an endotracheal tube (ETT) or laryngeal mask airway (LMA), as it puts the child into a deeper plane of anesthesia.

Ketamine hydrochloride, a dissociative anesthetic that can be used for the induction and maintenance of anesthesia, is occasionally utilized for pediatric patients undergoing short procedures, such as an examination under anesthesia.² An intramuscular injection of 5 to 7 mg/kg will provide approximately 30 minutes of anesthesia. Additional doses at one-half of the initial dose can be given intravenously. There is a prolongation of emergence with repeated doses. Some of the principal adverse reactions include tachycardia, hypertension,
laryngospasm, tonic-clonic movements, hypersalivation, nausea and vomiting, diplopia, nystagmus, and an elevation of IOP (which should be remembered when following pediatric patients with glaucoma). It is a respiratory stimulant that can become a respiratory depressant if an overdose is given.

During anesthesia, even in patients whose IOP is usually normal, an increase in pressure can produce permanent visual loss. If penetration of the globe occurs when the IOP is excessively high, blood vessel rupture with subsequent hemorrhage may transpire. The IOP becomes atmospheric when the eye cavity has been entered, and any sudden increase in pressure may lead to prolapse of the iris and lens and loss of vitreous. Since proper control of IOP is critical during such delicate intraocular procedures as in pediatric cataract surgery, ketamine is not the agent of choice.

However, in some developing world settings where inhalation agents are not available, ketamine is used for pediatric cataract surgery. After ketamine induction, a peribulbar injection of lidocaine is usually given followed by ocular massage prior to surgical entry into the eye.³ Bell phenomenon can be seen at any time during anesthesia when the patient’s depth of anesthesia has changed. It manifests as an upward (or sometimes downward) movement of the eye. It is usually a sign of the patient being in a lighter stage of anesthesia but not awake. This phenomenon can make exams under anesthesia, corneal measurements, and A and B scans difficult or impossible to perform. The anesthesia provider should be aware of this reaction and be prepared to “deepen” the anesthesia to facilitate these procedures.

Phenylephrine drops are commonly used to produce pupillary dilation in order to facilitate surgical access.⁴ As an alpha agonist mydriatic agent, some dramatic side effects may occur, ranging from transient hypertension with reflex bradycardia, ventricular dysrhythmias, and even pulmonary edema. For this reason, a 2.5% solution rather than a 10% solution of phenylephrine is recommended. Furthermore, absorption via the nasal mucosa may be reduced by occlusion of the nasal puncta via pressure on the inner canthus to prevent unintentional routing of the drug through the nasolacrimal duct. Treatment of the iatrogenic hypertension with beta-blockers is contraindicated since it can produce unopposed alpha-adrenergic stimulation. The anesthesia provider should be informed at the time of drop instillation so that he or she may monitor for a hypertensive response.

The oculocardiac reflex is triggered by pressure on the globe and by traction on the extraocular muscles, the conjunctiva, or the orbital structures.⁵

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