General anesthesia in neonates and children: Agents and techniques

INTRODUCTION — Pediatric anesthesia differs in important ways from anesthesia for adults. This topic will discuss general principles of preanesthesia preparation, induction and maintenance of general anesthesia, and emergence from anesthesia for the healthy child undergoing routine surgery.

Induction and maintenance of general anesthesia for adults are discussed separately. (See "Induction of general anesthesia: Overview" and "Maintenance of general anesthesia: Overview".)

PREOPERATIVE EVALUATION

●History and physical examination – All children should be evaluated with a preanesthesia medical history, review of systems, and an anesthesia directed physical examination. The preanesthesia evaluation is similar to that of an adult, with modifications appropriate for the child's stage of development, pediatric physiology, and family history. Important components of the preoperative history and physical examination for a child are shown in tables (table 1 and table 2).

A preanesthesia airway evaluation, including assessment of predictors of difficulty with airway management, should be performed in children, as it would be for adults, with particular attention to findings which may be associated with difficult intubation, such as reduced thyromental distance (micrognathia), decreased mouth opening, reduced neck mobility, or large tongue. The components of the airway examination for children are shown in a table (table 2). (See "Airway management for induction of general anesthesia", section on 'Airway assessment' and "Airway management for induction of general anesthesia", section on 'Prediction of the difficult airway'.)

●Laboratory assessment – Preoperative laboratory testing should be individualized, based on patient factors and institutional norms. Routine laboratory studies are usually not required in healthy children.  

•Hematologic testing – Preoperative hemoglobin testing is unnecessary for most healthy children, as it is not likely to yield useful information. In one study, routine hemoglobin testing found previously undetected anemia in only 0.29 percent of children scheduled for elective day surgery [1].  

Infants under four months of age may have physiological anemia and be at their postnatal hemoglobin nadir, but hemoglobin is rarely less than 8 g/dL. This level of anemia is not likely to delay surgery or affect outcome for the procedures commonly performed for young infants, such as inguinal hernia repair.

A complete blood count (CBC) should be measured preoperatively in children with chronic illnesses associated with anemia such as cancer, inflammatory bowel disease, and those who are taking drugs that may affect blood cell production (eg, anticonvulsants such as valproate). CBC and coagulation studies should be performed in patients with a suspected, known, or a family history of bleeding disorders, and prior to surgery that is likely to result in significant bleeding, such as tonsillectomy/adenoidectomy, cleft palate repair, and intracranial procedures.

•Electrolytes – Preanesthesia measurement of electrolytes is rarely necessary in healthy children, but should be performed in children with renal insufficiency, endocrine disorders, in those taking diuretics, or in children with history of vomiting/diarrhea, and those who have limited fluid intake because of enteral feedings.

•Pregnancy testing – Preoperative pregnancy testing for menarchal females, including adolescents, is controversial. A small percentage of young women may present for elective procedures with an unsuspected pregnancy, and history alone may be unreliable for predicting possible pregnancy in teenagers [2]. The prevalence of a positive preoperative pregnancy test in adolescents has been reported to be 0.5 to 1.2 percent [2-5].

Elective procedures that require anesthesia are avoided during pregnancy, because of the risks of surgery, anesthesia, and ionizing radiation for the pregnancy [6]. The American Society of Anesthesiologists Practice Advisory for Preanesthesia Evaluation states that preanesthesia pregnancy testing may be offered to females of childbearing age [7]. However, teenagers are often uncomfortable discussing sexual activity or the possibility of pregnancy, and may be unable to rationally choose whether to undergo pregnancy testing. Therefore, in many institutions, including the authors', all female patients >12 years of age, and menarchal females <12 years of age who undergo anesthesia or sedation are required to have a urine human chorionic gonadotropin (HCG) test performed on the day of the procedure [8].

Routine pregnancy testing raises potentially difficult ethical, confidentiality, and consent issues. A positive pregnancy result may be best handled with the assistance of a social worker, child life, or mental health professional.

●Patient selection for outpatient anesthesia – Surgical procedures are increasingly performed on an outpatient, or ambulatory, basis. Postoperative admission to the hospital may be required because of the surgical procedure (eg, major abdominal or orthopedic surgery, cardiac surgery), or specific patient clinical conditions.

•Healthy patients – Healthy patients, or those with chronic disease under good control (ie, American Society of Anesthesiologists [ASA] physical status 1 or 2) (table 3) are usually appropriate candidates for ambulatory surgery. Some states mandate a minimum age for surgery at ambulatory surgical facilities (eg, Pennsylvania ≥6 months), but younger infants may have ambulatory surgery at hospitals.

•Obstructive sleep apnea – Patients with significant obstructive sleep apnea (especially those less than three years of age) are at significant risk for airway obstruction and desaturation after adenotonsillectomy; these patients should have inpatient monitoring after surgery [9,10]. (See "Anesthesia for tonsillectomy with or without adenoidectomy in children", section on 'Postoperative care'.)

•Ex-premature infants – Ex-premature infants (born before 37 weeks gestation) are at risk for apnea after anesthesia or sedation. This risk decreases with increasing postmenstrual age (PMA) (ie, gestational age plus chronological age) with minimal risk between 56 and 60 weeks postconception. Ex-premature infants may require recovery room level of care overnight after anesthesia. (See "Anesthesia for ex-premature infants and children", section on 'Postoperative monitoring'.)

•Neonates – Most institutions require inpatient observation after anesthesia for infants ≤44 weeks PMA, since full term infants may be at risk for apnea after anesthesia in the first few weeks of life [11].

PATIENT AND PARENT OR CAREGIVER PREPARATION FOR ANESTHESIA — Preparation for pediatric anesthesia involves the patient, and in most cases the parent or caregiver as well.

Preoperative education — Both the patient and the family often experience stress and anxiety in anticipation of surgery. Preprocedural education and preparation may reduce anxiety, and improve compliance on the part of the patient with induction of anesthesia. Effective educational materials and methods include the following [12-14], which are used by the authors:

●Online teaching modules or videos

●Books or other printed material

●Child life interventions (modeling, play therapy)

●Virtual or in person operating room tour

Risks of anesthesia — In our experience, most parents or caregivers are more concerned about the risks of anesthesia for their children than the risks of surgery. Anesthesia in healthy children is very safe, and is associated with low risks of serious complications.

●Postoperative nausea and vomiting – The most common adverse events in the perioperative period in children include nausea and vomiting, as is true in adults. (See "Postoperative nausea and vomiting".)

●Perioperative respiratory adverse events – Perioperative respiratory adverse events (PRAE) are more common in children than adults, and are of greater concern. PRAEs include laryngospasm, bronchospasm, coughing, and oxygen desaturation, which occur most commonly during anesthetic induction and emergence. These events are more likely in children <2 years of age, especially those with a recent upper respiratory infection or asthma, but they can occur in any child. One goal for anesthetic management for children should be the prevention of PRAEs. (See "Anesthesia for the child with asthma or recurrent wheezing" and "Anesthesia for the child with a recent upper respiratory infection".)

●Anesthetic neurotoxicity – The effect of anesthesia and surgery on the developing brain is an area of active research and interest. In December, 2016 the US Food and Drug Administration (FDA) announced warnings about potential risks of negative effects on the developing brain from administration of anesthetics and sedative drugs to pregnant women and children under age three, especially for repeated exposures or procedures lasting more than three hours [15]. However, the labeling change is recommended based on evidence from animal and not human studies. The degree of risk remains unclear, and the best available evidence suggests that a single, brief exposure to anesthesia does not cause neurotoxicity in healthy young children. The effects of anesthesia and surgery on the brain in young children are discussed separately. (See "Neurotoxic effects of anesthetics on the developing brain".)

●Mortality – Mortality related to anesthesia is very rare in healthy children (likely <1/200,000 anesthetics), as it is in adults, though the true incidence is unclear. Perioperative cardiac arrest and mortality are more common during cardiac surgical procedures, in patients with significant comorbidities, and in infants and neonates. Data regarding the incidence of pediatric perioperative cardiac arrest and death come from prospective and retrospective reviews [16,17] and registry studies [18,19], with small numbers of events, and heterogeneity of patient populations and procedures. In one review of almost 93,000 pediatric anesthetics between 1988 and 2005 at a tertiary center, mortality for children who underwent noncardiac procedures was 1.6 per 10,000 anesthetics, compared with 115.5 per 10,000 anesthetics for cardiac procedures [17]. Most cardiac arrests (88 percent) occurred in patients with congenital heart disease, and the majority of cardiac arrests were caused by factors unrelated to anesthesia.

Preoperative fasting — Oral intake is routinely restricted before anesthesia, in an attempt to reduce gastric contents and therefore the risk of aspiration (table 4). However, prolonged preoperative fasting can increase anxiety and cause hypovolemia and hypoglycemia, especially in infants and young children. Clear liquids should be encouraged in healthy young children up to two hours prior to elective surgery, and parents or caregivers should receive specific instructions on which liquids are acceptable (ie, water, oral rehydration solutions, clear fruit juices without pulp, carbonated beverages, clear tea, and black coffee). Necessary medications should be administered with a sip of water.

Increasingly, recommended fasting intervals for liquids are being reduced, with some institutions allowing clear liquids almost immediately prior to surgery [20]. Some institutions, including the authors', have reported that reducing the fasting interval for clear liquids to one hour prior to anesthesia causes no increase in the occurrence of regurgitation, vomiting, or aspiration with induction of anesthesia [21,22].

Preoperative fasting in children is discussed in detail separately. (See "Preoperative fasting in children and infants".)

Usual medications — Most necessary medications are administered as usual on the morning of the procedure. However, we instruct patients to not take angiotensin receptor blockers on the day of surgery, since in our experience, these medications can cause intraoperative hypotension that is difficult to treat. We also instruct patients to stop metformin 24 to 48 hours prior to surgery, because of the incidence of lactic acidosis with fasting while taking metformin [23].

Prevention and treatment of preoperative anxiety — Anxiety and distress in the immediate preoperative period may be prevented or relieved with a variety of techniques, including premedication, distraction techniques, parental or guardian presence, and child life interventions [24]. Practice varies among institutions; we routinely premedicate pediatric patients. Unrelieved anxiety associated with anesthetic induction may result in a stormy induction requiring physical restraint of a crying, struggling child. Anxiety during induction may be associated with postprocedure behavioral changes including nightmares, separation anxiety, and aggression toward authority [25].  

●Sedatives and anxiolytics – Premedication reduces anxiety, improves compliance with induction, may provide amnesia for the induction, and may reduce postoperative negative behavioral changes during the first postoperative week [26]. Premedication is more effective than either parental or guardian presence at induction or preoperative teaching programs [27]. Medications commonly used for premedication are discussed here.

•Midazolam [28] – Midazolam is the most widely used premedication for children [29]. It is usually administered approximately 20 minutes prior to induction. Midazolam potentiates the respiratory depressant effects of opioids, and should be used with caution in patients with obstructive sleep apnea. (See "Anesthesia for tonsillectomy with or without adenoidectomy in children", section on 'Preparation for anesthesia'.)

Midazolam may be administered by oral, nasal, intramuscular, or intravenous routes, as follows:

Oral – The dose for premedication is 0.25 to 0.5 mg/kg orally, maximum 10 to 15 mg. It may leave a bitter aftertaste. Some formulations of oral midazolam may contain carbohydrate (eg, sucrose or dextrose), which is contraindicated in patients on the ketogenic diet. Clinicians should check with their institution's pharmacist regarding the available preparation's carbohydrate content. Some preparations contain sorbitol which is not contraindicated in patients on the ketogenic diet. If carbohydrates are in the formulation or in patients for whom red dye is contraindicated, the IV formulation may be administered orally or nasally.

Nasal – Midazolam may be administered nasally (0.2 to 0.3 mg/kg of the intravenous solution, via nasal spray) for children who resist oral medication. Nasal midazolam often causes a burning sensation in the nose [30], which may be reduced by prior administration of intranasal lidocaine spray (10 mg puff) [31].

Intravenous – If an IV is present, midazolam may be administered at doses from 0.025 to 0.1 mg/kg IV, maximum 6 mg for age six months to five years, maximum 10 mg for age >6 years.

Intramuscular – For uncooperative children, midazolam may be administered intramuscularly at the same dose as would be administered IV.  

•Ketamine – Intramuscular ketamine (3 mg/kg IM) may be particularly useful for premedication for a combative, uncooperative child who refuses oral premedication. For children who will accept oral medication, the combination of ketamine (3 to 6 mg/kg oral) with midazolam (0.5 mg/kg oral) may improve anxiolysis and behavior at separation from parents than either drug alone [32].

•Dexmedetomidine – Dexmedetomidine is effective for preoperative anxiolysis and may improve mask acceptance [33]. It may be as effective as midazolam [34], and may reduce emergence delirium, but has a slower onset (45 minutes) [35]. Dexmedetomidine may be administered nasally at a dose of 1 to 3 mcg/kg, or orally at a dose of 2.5 to 4 mcg/kg. In an observational study of 50 children, premedication with intranasal dexmedetomidine 1 to 3 mcg/kg was rapidly absorbed, achieving peak plasma concentration in a median of 37 minutes and maximal sedation at 45 minutes after administration [36].

●Parental/guardian presence – Parents or guardians are routinely present for induction in some pediatric hospitals, but this is less common in institutions where premedication is standard practice. Many anxious parents or guardians who think their children require their presence for induction become more relaxed and able to separate when they see the child relaxed and giggling after the midazolam takes effect. When children or parents/guardians refuse premedication, or when anxiety persists after administration of premedication, parental or guardian presence may be offered, though the presence of an anxious individual may be of no benefit for the child [37].

Usually only one parent or guardian is present for induction [38]. They should be prepared for potentially disturbing events during induction (holding the mask on the child's face, eye movements, alterations in breathing pattern), and they should realize that their role is to focus on and reassure their child, rather than to watch the monitors. The parent/guardian should expect to be escorted out of the operating room once the child is no longer benefitting from the presence of the parent. Establishing expectations in advance of induction is often greatly appreciated by the parent or guardian who may otherwise witness an unsettling event.

●Topical anesthesia – Topical anesthesia may be used to reduce or eliminate the pain of IV placement when IV induction is required (eg, for rapid sequence induction). (See 'Choice of induction technique' below.)

Local anesthetic creams (eg, LMX4 or EMLA cream) and patches (eg, Synera) require 20 to 60 minutes for maximal effect. They cause vasoconstriction, and may make the vein harder to see and cannulate.

Other options that may be applied immediately prior to IV start include an iontophoretic system for lidocaine (Numby stuff) [39], needleless administration systems for lidocaine (j-tip and Zingo), and a TENS-like system (Buzzy).

INDUCTION OF GENERAL ANESTHESIA — Prior to induction of anesthesia, the anesthesia machine, monitors, airway equipment, and drugs should be prepared in sizes and doses appropriate for the child. Atropine should always be immediately available at a unit dose (0.02 mg/kg) for treatment of bradycardia if necessary. (See "Induction of general anesthesia: Overview", section on 'Preparation for anesthetic induction'.)

Every effort should be made to prevent hypothermia prior to, during, and after anesthesia. For infants under six months of age or 5 kg weight, the operating or procedure room should be warmed to ≥80 degrees before the patient enters. Radiant heat lamps, forced air or fluid heating blankets, and warm cloth blankets can all be used to prevent hypothermia. (See 'Temperature control' below.)

Monitoring — The basic physiologic monitoring modalities used for adults during anesthesia are used for children as well, with appropriately sized equipment (table 5). (See "Basic patient monitoring during anesthesia".)

In adults, the electrocardiogram, pulse oximeter, and blood pressure cuff are usually applied prior to induction of anesthesia to obtain baseline readings. In children, monitors are often applied after or during induction, to avoid upsetting the child. If preoperative readings are attempted, it may be difficult to obtain true baseline vital sign measurements in an uncooperative, anxious child.

Monitoring issues specific to children include the following:

●Blood pressure monitoring – Blood pressure cuffs are available in a range of sizes, and use of a correctly sized cuff is important for accurate measurements. We have available four cuff sizes from infant to adult, and five neonatal cuff sizes. The cuff should have a bladder with a width that is approximately two-thirds the length of the upper arm, and a length that encircles 80 to 100 percent of the upper arm. We use the same sizing when the cuff is placed on the lower leg (ie, cuff width two-thirds the length of the lower leg). Undersized cuffs tend to give falsely elevated readings, while oversized cuffs give falsely low readings (figure 1 and figure 2). (See "Definition and diagnosis of hypertension in children and adolescents", section on 'Cuff size and placement'.)  

Continuous blood pressure monitoring with an indwelling arterial catheter may be indicated for some high risk patients or high risk surgery, or for repeated blood gas sampling.

●Pulse oximetry – Disposable and reusable pulse oximeter probes are available in pediatric sizes. In older children the probe is usually placed on a finger or ear lobe, similar to adults. In neonates and infants, the probe should be placed wherever the probe fits best, which may be the great toe, the thumb, or the outer aspect of the foot or palm. The probe should be positioned with its two diodes directly opposite one another to obtain an accurate reading.

●Electrocardiography – A three-lead electrocardiogram (ECG) is most commonly used in children with normal hearts because of the low likelihood of ischemic events. A five lead ECG is used in infants and children with heart disease, and those having cardiac surgery. In infants with delicate skin, neonatal ECG electrode pads are used. These electrodes have a gentler adhesive and are smaller than adult ECG electrodes.

●Monitors of ventilation – Ventilation is ideally assessed by end-tidal CO₂ (ETCO₂) capnography, or alternatively (when unavailable, for example, during bronchoscopy) by observation of chest excursion or auscultation of breath sounds. The capnogram is a graphic representation of expired CO₂ and is most accurate at its plateau. (See "Basic patient monitoring during anesthesia", section on 'Capnography'.)

The rapid respiratory rate in children may cause a falsely low ETCO₂ reading, since inspiration may start before full expiration has occurred, stopping the rise of the ETCO₂ trace to its peak (figure 3) [40].  

●Temperature – Body temperature should be measured by an esophageal, nasal, axillary, or rectal probe, appropriately sized for the patient. (See "Perioperative temperature management", section on 'Temperature monitoring'.)

Choice of induction technique — Inhalation induction, with administration of anesthetic gas by face mask, is the most common induction technique in young children, and is used primarily to avoid the trauma of intravenous (IV) catheter placement while the child is awake. However, an IV allows the clinician to administer anesthetic and emergency medication with a rapid effect. Therefore, IV induction is preferred for patients who require rapid endotracheal intubation for airway protection, for some patients with a high likelihood of difficulty with airway management, for those at risk for cardiovascular instability during induction, and for patients with contraindications to the use of inhalation anesthetics (eg, at risk for malignant hyperthermia). IV induction may be preferred for patients with the following conditions:

●Obesity [41,42]

●High risk of aspiration (eg, pyloric stenosis, achalasia, gastroparesis, recent oral intake, poor handling of oral secretions, recent nausea and vomiting, long bone fractures [43]) (see "Rapid sequence induction and intubation (RSII) for anesthesia" and "Rapid sequence induction and intubation (RSII) for anesthesia", section on 'Indications')

●Need for malignant hyperthermia precautions (see "Susceptibility to malignant hyperthermia: Evaluation and management")

IV induction may be preferred by the patient or parents/caregivers, and older children may accept placement of an IV catheter and subsequent IV induction.

Induction of anesthesia typically occurs more slowly during inhalation induction, and the patient spends more time in the excitement stage of anesthesia, often referred to as Stage II (table 6). The stages of anesthesia were initially developed to characterize the increasing depth of anesthesia with ether as the sole anesthetic, and are less relevant with newer, more rapidly acting inhalation anesthetics. Nonetheless, the idea that patients go through a period of excitement and delirium (Stage II) during induction and emergence from anesthesia is an important concept. During Stage II, patients are at risk for laryngospasm, coughing, and vomiting. For this and other reasons, IV induction may be preferred for children who are at particularly high risk for laryngospasm and other perioperative respiratory adverse events (eg, patients with recurrent wheezing or recent upper respiratory infection). (See "Anesthesia for the child with asthma or recurrent wheezing", section on 'Intravenous versus inhalation induction'.)

Children are at higher risk for laryngospasm than adults [44], and most laryngospasm occurs during Stage II of anesthesia.

Inhalation induction — Goals for inhalation induction include a smooth, atraumatic experience for the child, with rapid induction of unconsciousness, while avoiding overdose of anesthetic agents.

Pediatric physiology and inhalation induction — Inhalation induction is faster in healthy children than it is in adults, because of differences in pulmonary and cardiac physiology. Cardiac output in children is higher than it is in adults, and in general, higher cardiac output slows the uptake of inhalation anesthetics. Nonetheless, uptake and distribution of volatile anesthetics is more rapid in children because of their increased respiratory rate, and because a higher proportion of cardiac output is distributed to the organs of pharmacologic effect (ie, brain, solid organs), compared with adults. The speed of induction is also influenced by the fresh gas flow, concentration of delivered inhalation anesthetic, and controlled ventilation, in addition to the physicochemical properties of the specific inhalation agent. (See "Induction of general anesthesia: Overview", section on 'Inhalation anesthetic induction' and "Inhalation anesthetic agents: Properties and delivery", section on 'Factors affecting inhalation anesthetic delivery'.)

Children are at risk for hypotension with administration of high doses of inhalation anesthetic agents during induction. Cardiac output and blood pressure are dependent on heart rate and preload in children, primarily because their cardiac ventricles are relatively noncompliant. Thus, the bradycardia that may be associated with high concentrations of inhalation agents may be poorly tolerated. Bradycardia can be minimized by gradual increase in the concentration of inhalation agent during induction. If bradycardia occurs, atropine (0.01 mg/kg IV or 0.02 mg/kg IM) or glycopyrrolate (O.005 mg/kg IV or 0.01 mg/kg IM) should be administered.

Inhaled anesthetics for induction — Each of the anesthetic inhalation agents has unique characteristics that affect the safety and efficacy for inhalation induction. (See "Induction of general anesthesia: Overview", section on 'Inhalation anesthetic induction'.)

●Nitrous oxide – Nitrous oxide is a relatively odorless gas that is generally very well tolerated in healthy children, as either a primary agent or adjunct to the delivery of halogenated compounds. Nitrous oxide may be administered to achieve unconsciousness, but is not potent enough to allow airway manipulation when used as a sole agent. Nitrous oxide speeds the induction of high solubility gases like halothane but adds little to the speed of induction of less soluble gases such as sevoflurane. Introduction of nitrous oxide is odorless and if the patient accepts the mask, several minutes of nitrous oxide may decrease the aversive response to the introduction of the more malodorous sevoflurane. Often an inhalational induction will include either high concentrations of nitrous oxide and oxygen (limited to 70 percent N₂O and 30 percent O₂ to prevent hypoxemia), or a combination of N₂O, O₂, and sevoflurane with nitrous oxide discontinued after the patient loses consciousness to raise the FiO₂. (See "Induction of general anesthesia: Overview", section on 'Nitrous oxide gas' and "Inhalation anesthetic agents: Clinical effects and uses", section on 'Nitrous oxide'.)

●Sevoflurane – Sevoflurane is the most commonly used agent for inhalation induction in the United States. It is relatively insoluble, which provides a rapid onset. It is less pungent, and less irritating to the airway than desflurane and isoflurane, and is associated with less airway related problems (ie, laryngospasm and bronchospasm) during induction and emergence. (See "Inhalation anesthetic agents: Clinical effects and uses", section on 'Sevoflurane' and "Anesthesia for the child with asthma or recurrent wheezing", section on 'Inhalation agents'.)

●Desflurane – Desflurane is not routinely used for inhalation induction. Despite its faster onset and lower solubility, it has been associated with increased airway reactivity that may predispose to laryngospasm and bronchospasm [45], which are more challenging to manage without an intravenous catheter in place. (See "Inhalation anesthetic agents: Clinical effects and uses", section on 'Desflurane' and "Anesthesia for the child with asthma or recurrent wheezing", section on 'Inhalation agents'.)

●Isoflurane – Isoflurane is rarely used for inhalation induction, because of its noxious smell, slower onset than the other potent inhalation agents, and increase in laryngospasm and coughing, compared with sevoflurane. (See "Inhalation anesthetic agents: Clinical effects and uses", section on 'Isoflurane'.)

●Halothane – Halothane is no longer used in the United States, primarily because of concerns about hepatotoxicity, but is commonly used in other parts of the world, especially for children. (See "Maintenance of general anesthesia: Overview", section on 'Halothane'.)

Halothane is a profound myocardial depressant, and can cause bradycardia and hypotension. These effects are of particular concern in infants, whose cardiac output is rate dependent. Atropine (IM or IV) is often required during inhalation induction with halothane.

Halothane also sensitizes the myocardium to catecholamines (eg, endogenous sympathetic stimulation, administered epinephrine or norepinephrine), and can cause ventricular arrhythmias.

Inhalation induction technique — There are many ways to perform inhalation induction, and the technique used must be appropriate for the patient's age and developmental level. (See "Induction of general anesthesia: Overview", section on 'Induction with supraglottic airway placement'.)

●Infants – Infants are usually upset by having a mask placed over their face, regardless of the odor of the gas. The mask is gradually applied while administering sevoflurane 5% with or without 70% nitrous oxide in oxygen. Sevoflurane is increased to 8% as tolerated.

●Toddlers – Toddlers are induced similarly to infants, although nitrous oxide alone with oxygen may be used for the first several breaths prior to introducing sevoflurane to achieve some level of "stunning" prior to the "smelly gas". We apply a pleasant smelling ointment (usually fruit flavor lip balm) to the inner surface of the face mask to obscure the odor of the anesthetic gas.

●School age children – Older children can often be engaged by telling them the mask is like an astronaut's mask and that they are like an astronaut blasting into space, breathing oxygen to protect them. Similar to toddlers, a pleasant smelling lip balm is added to the mask, and sevoflurane is administered with or after nitrous oxide in oxygen, depending on their degree of cooperation.

●Teenagers – Teenagers may be induced in a manner similar to school age children. Alternatively, if cooperative, they may be able to perform a single breath induction. For a single breath induction, the breathing circuit is primed with 8% sevoflurane and 70% N₂O. The patient expires completely, the mask is placed tightly over his or her face, and the patient then inspires fully and holds his or her breath. This achieves rapid loss of consciousness, but is often followed by return to Stage II anesthesia.

Alternatively, teenagers can start with nitrous oxide/oxygen for a few minutes followed by IV start and subsequent IV induction.

Once anesthesia deepens and the patient has reached Stage III anesthesia, the concentration of sevoflurane should be reduced to minimum alveolar concentration (MAC) level, closer to 3 percent. The signs of reaching Stage III include a slower, regular rate of respiration, decreased heart rate, and cessation of muscle movements. Eyes are midline, not divergent.  

Although it is possible to achieve a depth of anesthesia sufficient for endotracheal intubation with sevoflurane alone, it can take several minutes for this to occur. Most commonly depth of anesthesia is increased by the administration of propofol 2 to 3 mg/kg after the intravenous catheter is placed [46-48]. Alternatively, muscle relaxant can be given, if indicated by the procedure.

IV induction — A variety of anesthetic induction agents, opioids, and other adjunctive agents may be administered for IV induction of anesthesia. IV induction in adults is discussed separately. (See "Induction of general anesthesia: Overview", section on 'Intravenous anesthetic induction'.)

Adults are routinely preoxygenated before induction of anesthesia to increase oxygen reserve. (See "Rapid sequence induction and intubation (RSII) for anesthesia", section on 'Preoxygenation'.)

Preoxygenation may not be possible in young children, who may not accept placement of a face mask. High flow oxygen can be administered by mask placed as close to the child's face as is tolerated, to enrich the inhaled air with oxygen.

Intravenous induction medications — In general, children have a higher volume of distribution for intravenous medications, and may require higher initial doses for clinical effect.

●Atropine – Some clinicians, including one of the authors, routinely administer atropine (0.02 mg/kg IV) to neonates prior to IV induction, especially for rapid sequence induction and intubation, to prevent vagally mediated bradycardia during laryngoscopy in these patients. Other clinicians do not administer prophylactic atropine, and instead treat bradycardia if it occurs.

●Induction agents

•Propofol – Standard induction doses of propofol tend to be higher on a milligram per kilogram basis in children (3 mg/kg or more) than adults (2 mg/kg), due to their increased volume of distribution (volume of central compartment is 50 percent greater in children) as well as up to 25 percent faster clearance [49,50]. The dose of propofol is highest in infants, declines in children, then peaks again in adolescents [51,52]. Children have slightly higher clearance of propofol than adults [50]. Children often routinely tolerate induction with higher per kilogram doses of propofol without significant hypotension [51,53].

There is limited data on the optimal dosing of propofol in healthy neonates [54]. The product labeling for propofol includes the Food and Drug Administration of the United States recommendation that propofol should not be used for induction of anesthesia for children under three years of age, or for maintenance of anesthesia for children under two months of age, or for sedation in children, because safety and dosing guidelines have not been established [55]. However, similar to many other medications used in pediatrics, propofol is widely used, judiciously and when indicated, for children of all ages by pediatric anesthesiologists, including the authors.

Propofol often causes pain on injection, which may be poorly tolerated in children. This can be attenuated by prior administration of a fast-acting opioid (fentanyl or remifentanil 1 mcg/kg IV), or lidocaine 1 mg/kg IV.  

•Dexmedetomidine – Dexmedetomidine 0.5 to 2 mcg/kg is effective as either a single-agent or an adjunct to other induction medications and is unique in its ability to provide analgesia and hypnosis while preserving respiratory drive. Similar to adults, dexmedetomidine is useful for induction for procedures in which spontaneous respiration must be maintained during potent stimulation, such as rigid bronchoscopy.

•Ketamine – Ketamine is unique among the parenteral induction agents in that it can be administered intramuscularly (IM), at a dose of 5 to 10 mg/kg IM. Thus, ketamine may be useful for children who will not cooperate with either inhalation or IV induction.

Ketamine 2 mg/kg IV can also be used for intravenous induction, and is particularly useful for patients who are likely to develop hypotension on induction due to hypovolemia, hemorrhage, sepsis, or cardiovascular compromise. (See "General anesthesia: Intravenous induction agents", section on 'Advantages and beneficial effects'.)

An anti-sialogogue (eg, atropine 0.02 mg/kg IV or IM, maximum dose 0.4 mg, or glycopyrrolate 0.04 mg/kg IV) should be administered along with ketamine to prevent the increase in salivation and upper airway secretions that can occur. In addition, a benzodiazepine should be administered to prevent ketamine induced dysphoria and hallucinations. Such psychotomimetic effects after ketamine administration are more common in older children than in infants.

●Opioids

•Fentanyl – When used in conjunction with additional induction agents such as propofol, lidocaine, ketamine, or sevoflurane, fentanyl 1 to 2 mcg/kg can be administered to facilitate a smooth induction, minimize pain, and blunt the reflexes associated with the noxious stimulation of airway instrumentation. Opioids should be used with caution in patients with sleep apnea, given their exquisite sensitivity to the sedating effects. The use of fentanyl for induction of premature infants should also be carefully considered, given their sensitivity to the respiratory depressant effects. By case report and observation, the rapid administration of fentanyl has been associated with "rigid chest" in some children, most commonly reported in neonates [56]. Onset of analgesia within two minutes of administration makes this a better choice than slower-acting opioids for induction.

•Remifentanil – Remifentanil 1 to 2 mcg/kg has a more rapid onset and shorter duration of action when compared with fentanyl, but it has been linked with significant bradycardia in children when given in bolus or high doses. Its use should be tempered in such a way to avoid significant bradycardia, or pretreatment with atropine should be considered.

●Lidocaine – Intravenous lidocaine (1 mg/kg IV) may be administered to reduce the pain of propofol administration, blunt the response to airway manipulation, and to supplement the anesthetic effect of the induction agent. The total dose of local anesthetic administered, including the amount used for local anesthetic infiltration by the surgeon, must be monitored and limited to avoid systemic toxicity.

●Neuromuscular blocking agents – Neuromuscular blocking agents (NMBAs) are routinely administered to facilitate laryngoscopy in adults. In pediatric anesthesia, if neuromuscular blockade is not required for the surgical procedure, it is increasingly common to intubate with induction agents without an NMBA.

However, many clinicians prefer to administer NMBAs for intubation in neonates, in order to ensure optimal conditions for a quick intubation, with a lower dose of propofol. Neonates desaturate quickly during apnea because of high oxygen consumption, and often cannot be preoxygenated fully, so they have little oxygen reserve. Optimal conditions and successful intubation on the first attempt may be facilitated by the use of NMBAs [57]. A randomized trial compared propofol (2 mg/kg), alfentanil (14 mcg/kg) and rocuronium (0.3 mg/kg) as adjuncts for intubation after sevoflurane induction for children one to nine years of age who underwent frenulectomy (surgical duration 10 minutes) [58]. Rocuronium and alfentanil provided better intubating conditions than propofol, with less movement or coughing, with similar times to emergence and recovery. [58]. However, in no patient was intubation difficult or prolonged, and many clinicians use a higher propofol dose (3 mg/kg) for younger children to facilitate intubation after sevoflurane induction.

Neonates have a higher volume of distribution for both nondepolarizing NMBAs and succinylcholine, and therefore require slightly higher initial doses than older children and adults. However, neonates are more sensitive to nondepolarizing NMBAs, and require smaller incremental doses for maintenance of relaxation. Neonates' sensitivity to succinylcholine is similar to older children and adults. (See "Clinical use of neuromuscular blocking agents in anesthesia".)

Administration of succinylcholine for routine intubation in children has largely been abandoned. The Food and Drug Administration of the United States has issued a boxed warning for succinylcholine for children, except for emergency airway management, over concerns for acute rhabdomyolysis and hyperkalemia in children with undiagnosed muscular dystrophies [59,60]. Despite this warning, succinylcholine can be used in select patients (eg, those who require rapid sequence induction), and appropriate screening is paramount prior to its administration. (See "Clinical use of neuromuscular blocking agents in anesthesia", section on 'Succinylcholine'.)

Rapid sequence induction and intubation — Similar to adults, rapid sequence induction and intubation (RSII) may be performed for patients at high risk of aspiration during induction of anesthesia. (See "Rapid sequence induction and intubation (RSII) for anesthesia".)

Mask ventilation is typically not performed in adults during RSII. In infants, gentle positive pressure ventilation should be performed after loss of consciousness, along with cricoid pressure, to avoid oxygen desaturation while waiting for the effect of neuromuscular blocking agents. Infants are at high risk of hypoxemia and atelectasis during apnea, because of their high rate of oxygen consumption. (See "Rapid sequence induction and intubation (RSII) for anesthesia", section on 'Mask ventilation'.)

Airway management during induction — The devices that may be used for airway management for children during anesthesia are similar to those that are used in adults. Airway obstruction and laryngospasm are more common during induction of anesthesia in children than in adults, and may occur before intravenous access has been established.

Choice of airway device — Most airway devices are available in a range of sizes, including those that are appropriate for neonates. The choice of airway device for pediatric anesthesia is discussed separately. (See "Airway management for pediatric anesthesia", section on 'Choice of airway device'.)

Airway obstruction — The reduction in airway tone associated with anesthesia and their relatively large tongue predisposes children to airway obstruction during induction. Jaw thrust, oral or nasopharyngeal airways, and continuous positive airway pressure with a tight mask seal are all strategies for maintaining a patent airway during mask ventilation, similar to adults. (See "Basic airway management in children".)

Airway obstruction should be corrected immediately during induction. Children develop hypoxemia more rapidly during airway obstruction than adults, primarily because of markedly increased oxygen consumption (table 7), and bradycardia, hypotension, and even cardiac arrest may occur.

Laryngospasm — Laryngospasm can occur during induction, maintenance, or emergence from anesthesia, and most commonly occurs during light levels of anesthesia. Laryngospasm must be recognized and treated rapidly to prevent complications. In most cases, laryngospasm responds to treatment without sequelae, but oxygen desaturation, bradycardia, negative pressure pulmonary edema, aspiration, and cardiac arrest can occur. Risk factors, prevention, and management of laryngospasm are discussed separately (algorithm 1). (See "Complications of pediatric airway management for anesthesia", section on 'Laryngospasm'.)

Intraoperative bronchospasm in children is discussed separately. (See "Anesthesia for the child with asthma or recurrent wheezing", section on 'Intraoperative bronchospasm'.)

MAINTENANCE OF ANESTHESIA — Inhalation anesthesia is the mainstay of pediatric anesthesia, with the exception of children at risk of malignant hyperthermia (MH). Similar to adults, total intravenous anesthesia is used for patients at risk of MH, and may be used for a variety of other indications. The general considerations for maintenance of anesthesia, and characteristics of inhalation and intravenous anesthetic agents, are discussed separately. (See "Maintenance of general anesthesia: Overview", section on 'Selection of maintenance techniques'.)

Considerations specific to pediatric patients are discussed here. Use of these agents for induction of anesthesia is discussed above. (See 'Inhaled anesthetics for induction' above and 'IV induction' above.)

Volatile inhalation anesthetics — The concentration of volatile inhalation agents (ie, sevoflurane, halothane, isoflurane, desflurane) required for anesthesia (ie, minimum alveolar concentration [MAC]) is higher in children than it is in adults. MAC is highest in infants up to six months of age, and decreases thereafter, with lowest levels in older adults [61-64]. As an example, the MAC for sevoflurane in full term neonates is 3.3 percent, and decreases to 2.5 percent in children age 6 months to 10 years [64].

Intravenous maintenance medications — Intravenous medications may be administered as part of total intravenous anesthesia, or as adjuncts to inhalation anesthesia.

Sedative-hypnotic agent: Propofol — Propofol is the most commonly used intravenous agent for maintenance of anesthesia, for total intravenous anesthesia, or after inhalation induction with volatile anesthetics. Children have increased volume of distribution, shorter elimination half-life, and higher plasma clearance for propofol, than adults. Thus, the dose requirement for infusion of propofol in children is approximately twice that of adults [65,66], even though a similar blood level of propofol is required for adequate anesthesia. Propofol infusion rates as high as 250 to 300 mcg/kg/min IV may be necessary, and are usually well tolerated without hypotension [67].

Propofol anesthesia reduces the incidences of postoperative nausea and vomiting and emergence delirium. (See "Postoperative nausea and vomiting", section on 'Reduction of baseline risk' and "Emergence delirium and agitation in children", section on 'Anesthetics'.)

Neuromuscular blocking agents — Neuromuscular blocking agents (NMBAs) are administered during maintenance of anesthesia when they are required by the surgical procedure (eg, laparotomy or laparoscopy) or when they may help to optimize ventilation. (See "Clinical use of neuromuscular blocking agents in anesthesia".)

Train-of-four peripheral nerve stimulators should be used in children to guide dosing of NMBAs, as they are in adults. Quantitative, accelerometry based monitors cannot be used in neonates because the sensitivity is not high enough for the small motions of the infant thumb.

Sugammadex has been approved by the US Food and Drug Administration for reversal of NMBAs in children older than two years of age. As with other drugs, sugammadex is being used "off-label," by some anesthesiologists for children younger than two years of age. A single institution review of reversal of NMBAs over a two year period in children under two years of age reported no adverse effects of sugammadex (331 doses of sugammadex), and similar average time from the end of surgery and moving out of the operating room after reversal with sugammadex or with neostigmine [68]. Advantages of sugammadex include the ability to reverse deeper levels of neuromuscular blockade than neostigmine, and lack of the cholinergic effects of neostigmine. Reversal of neuromuscular blockade is discussed in detail separately. (See "Clinical use of neuromuscular blocking agents in anesthesia", section on 'Reversal of neuromuscular block'.)

Opioids — Similar to adults, opioids are administered during anesthesia for children to augment other anesthetics, as part of total intravenous anesthesia, and for postoperative pain control. Perioperative opioid administration is discussed in detail separately. (See "Perioperative uses of intravenous opioids in adults: General considerations".)

Antiemetics — Children are at higher risk of postoperative vomiting than adults, and antiemetics are routinely administered during anesthesia. Risk factors, prophylaxis, and treatment of postoperative vomiting in children are discussed separately. (See "Postoperative nausea and vomiting".)

Fluid management — The goals for intraoperative fluid management in pediatric patients are to replete fluid deficits related to fasting, optimize their preload dependent cardiac output, and replete intraoperative blood loss. Hypotension in the healthy pediatric patient during anesthesia is often fluid-responsive (with a 10 to 20 mL/kg bolus of normal saline or lactated Ringer's solution), and may be less likely to require vasopressor administration than in sicker or older patients. Intravenous fluid should be administered cautiously to children with cardiac or pulmonary disease.

Isotonic crystalloid intravenous solutions without dextrose (eg, normal saline, Ringer's lactate) should be administered intraoperatively. Similar to adults, large volume resuscitation with normal saline may cause hyperchloremic metabolic acidosis in children (see "Intraoperative fluid management", section on 'Crystalloid solutions'). In children at risk for hypoglycemia (eg, infants under six months of age whose hepatic immaturity precludes effective gluconeogenesis or glycogenolysis, or those with muscle or metabolic disease), dextrose-containing fluids should be available for correction of low blood sugar. If glucose-free fluids are administered in infants <6 months of age for surgery lasting >60 minutes, blood glucose should be monitored utilizing point-of-care (POC) fingerstick testing intraoperatively. Dextrose-containing fluids may also be administered as an infusion to maintain euglycemia if necessary but should not represent the mainstay of maintenance or repletion fluid and blood sugar should be monitored (for hyper- as well as hypoglycemia) as mentioned above.

Blood loss should be monitored carefully. Children have blood volumes from 70 to 90 mL/kg. In very young children, seemingly small amounts of blood loss can cause significant hypotension. Iatrogenic hemodilution should be avoided, especially during the physiologic nadir for hemoglobin at three to six months of age.

Ventilation — Similar to adults, children are increasingly ventilated using a lung protective strategy during anesthesia, including tidal volumes of approximately 6 mL/kg, low peak and plateau pressures, and modest positive end expiratory pressure (eg, 5 cm H₂O). (See "Mechanical ventilation during anesthesia in adults", section on 'Lung protective ventilation during anesthesia'.)

The goal for oxygen saturation for neonates is lower than for older children and adults (90 to 94 versus >95 percent), and the fraction of inspired concentration of oxygen should be set accordingly. This goal balances the need for adequate tissue oxygenation with concerns for the development of reactive oxygen species. Hyperoxia has been implicated in retinopathy of prematurity, apoptosis, DNA injury, and end-organ inflammation [69].

Ventilation should be set to maintain end tidal carbon dioxide (ETCO₂) between 35 and 40 mmHg. For the early neonate, significant hypercarbia and resultant respiratory acidosis may precipitate a treacherous reversion to fetal circulation. The rapid respiratory rate in children may cause a falsely low ETCO₂ reading, since inspiration may start before full expiration has occurred, stopping the rise of the ETCO₂ trace to its peak (figure 3). The true ETCO₂ can be determined by pausing the ventilator briefly to allow full exhalation to occur.

The differences between adult and infant respiratory physiology are shown in a table (table 7). Whereas weight based functional residual capacity and tidal volume are similar, minute ventilation and oxygen consumption are markedly higher in infants. This means that neonates and small infants desaturate quickly during apnea, and there is less time to take corrective action. The high chest wall compliance, and protuberant abdomens of young infants favor lung volume loss under anesthesia. As closing capacity can exceed functional residual capacity (FRC) in infants, maintenance of continuous positive airway pressure (CPAP) is important to prevent atelectrauma.

Prior to the development of sophisticated flow meters in modern anesthesia machines, traditionally children were ventilated by pressure-driven modes, as very small tidal volumes were difficult to set and sense with accuracy. Pressure control ventilation with auto flow adjustment for changes in compliance is most commonly used. Such adjustments are particularly important during abdominal insufflation for laparoscopy, as in adults. The tidal volume is followed, and peak pressure or inspiratory time is increased if tidal volume falls. (See "Mechanical ventilation during anesthesia in adults", section on 'Pressure control with volume guarantee'.)

Temperature control — Maintenance of normothermia during anesthesia is important in all patients, and is especially important in small children. Hypothermia has been associated with delayed emergence, altered pharmacokinetics, poor tissue perfusion, and potential reversion to transitional circulation in the neonate. In addition, vasoconstriction from hypothermia can make intravenous (IV) access particularly difficult in small children.

Infants and small children are at risk for hypothermia if exposed to cold environments for several reasons. The surface area to mass ratio of the infant is twice that of the adult, infants have thin skin and are unable to shiver to generate heat, and the relatively large head (ie, up to 20 percent of total skin surface area) may be a significant source of heat loss.

Forced air or water warming blankets and intravenous fluid warmers should be routinely used, and the patient should be kept covered as possible. The operating room temperature should be raised during skin preparation and before draping.  

Regional anesthesia — Regional anesthesia is increasingly used in pediatric anesthesia, either for postoperative pain control, or as the sole anesthetic. Regional anesthesia reduces the required doses of other anesthetics and opioids; this may be beneficial for patients at high risk of postoperative apnea (eg, neonates, patients with obstructive sleep apnea).

In contrast with adults, most regional anesthetic procedures are performed after the induction of general anesthesia in children [70,71].  

EMERGENCE AND EXTUBATION — The goal should be to achieve a smooth, controlled emergence from anesthesia, without laryngospasm or bronchospasm, oxygen desaturation, coughing, or vomiting. The endotracheal tube or supraglottic airway can be removed once the patient is awake, or at a deep level of anesthesia, but should not be removed during the excitement stage (ie, Stage II) as the patient emerges. Airway manipulation, including extubation, can cause laryngospasm during Stage II.

Deep versus awake extubation — We extubate most patients awake. The choice between awake and deep extubation is based on patient factors and clinician preference. Awake extubation allows the return of airway tone and airway protective reflexes, and theoretically reduces the risk of post-extubation airway obstruction and laryngospasm. However, in children with risk factors for bronchospasm, or in whom coughing should be avoided for surgical reasons, deep extubation may be preferred. In one small study, there were no differences in any adverse respiratory events or oxygen desaturation between children randomly assigned to deep versus awake extubation after general anesthesia [72].

Awake extubation may be preferred for children at risk for the following:

●Aspiration (eg, ileus, upper gastrointestinal bleeding)

●Airway obstruction (eg, after cleft palate repair, craniofacial anomalies, obstructive sleep apnea)

●Airway muscle weakness associated with neuromuscular or cranial nerve disorders

Deep extubation may be associated with less coughing, and may be preferred in the following situations:

●Patients at high risk of bronchospasm (eg, asthma, recurrent wheezing)

●After thyroidectomy, due to risk of hematoma at surgical site, and airway compromise

●After tracheal surgery, to avoid disruption of the suture line

Awake extubation — Prior to awake extubation, the neuromuscular blocking agent (if used) should be completely reversed, the oropharynx should be suctioned, the patient's eyes should be conjugate (rather than deviated) as a sign of recovery from anesthesia, and the patient should respond by grimacing or opening eyes in response to stimulation or suctioning. A single institution prospective observational study of 600 pediatric awake intubation found that five factors were each associated with successful extubation, including presence of conjugate gaze, facial grimace, eye opening, purposeful movement, and tidal volume > 5 mL/kg. [73]. Predictive value increased with the presence of increasing numbers of these factors; one factor had a positive predictive value of 88.4 percent, whereas the presence of 5 factors had a 100 percent positive predictive value. " (See "Emergence from general anesthesia", section on 'Emergence with an endotracheal tube'.)

Deep extubation — Prior to deep extubation, the patient should be breathing spontaneously, with regular respirations and adequate tidal volumes. Confirm deep anesthesia before extubation by lack of coughing or change in ventilatory pattern with the following maneuvers:

●Move the endotracheal tube in the trachea to mimic the stimulation of extubation.

●Thoroughly suction the oropharynx. Retained oropharyngeal secretions may precipitate laryngospasm during emergence after deep extubation.

●Empty the stomach with an orogastric tube.

After deep extubation, a patent mask airway should be established and maintained during emergence and transport to the post-anesthesia care unit (PACU). We transport patients to the PACU in the lateral decubitus position, slightly head down, to maintain airway patency and allow secretions to drain.  

Deep versus awake removal of SGA — We remove most supraglottic airways (SGAs) while the patient is still deeply anesthetized. Awake removal of an SGA allows return of airway tone and protective reflexes while a patent airway is maintained. However, an SGA does not protect against aspiration or laryngospasm during emergence, and the patient may cough, bite on the LMA tube, gag, or vomit during emergence. If the patient bites on the tube while emerging, it may be impossible to remove the device, or to ventilate.

The decision to remove an SGA deep or awake should be based on patient factors and clinician preference, and data to support either choice is inconclusive [74]. A meta-analysis of 15 randomized controlled trials in adults (five studies) and children (11 studies) reported no difference in laryngospasm or oxygen desaturation with deep versus awake SGA removal [75]. Coughing was less frequent after deep removal (13.9 versus 19.4 percent) but airway obstruction was more common (15.6 versus 4.6 percent). The quality of the evidence for all outcomes was low or very low.

Awake removal of an SGA may be preferred in patients who have copious upper airway secretions, anatomic airway obstruction, or bleeding in the airway.  

Awake SGA removal — Awake removal of an SGA is similar to awake extubation. (See 'Awake extubation' above.)

The oropharynx should be suctioned on either side of the SGA.

Deep SGA removal — Prior to deep removal of an SGA, the patient should be breathing spontaneously with regular respirations and adequate tidal volume. If the patient has been maintained on pressure support, the mode of ventilation should be changed to spontaneous. Adequate depth of anesthesia should be confirmed as follows:

●Maintain expired anesthetic gas concentration at ≥1 MAC.

●Suction the oropharynx on both sides of the SGA, and verify no change in ventilatory pattern or movement in response to suction.

After removal of the SGA, an oral airway should be placed, ventilation should be maintained by mask, and the anesthetic agent should be discontinued. The patient should be transferred to the PACU stretcher or bed with care taken to avoid neck flexion, which could cause stimulation of the larynx by the oral airway with positioning to ensure continued airway patency. The patient should be transported to the PACU with oxygen administration via Mapleson circuit or other apparatus capable of delivering continuous positive airway pressure (CPAP) and/or positive pressure ventilation.

Emergence laryngospasm — In our experience, laryngospasm is more common during emergence from anesthesia than during induction.

●Prevention – Strategies for prevention of laryngospasm on emergence include the following:

•Suction the oropharynx thoroughly to remove secretions, either while the patient is still deeply anesthetized, or awake, but not during light anesthesia.  

•Avoid extubation or airway manipulation during a light level of anesthesia.

•Administer lidocaine via laryngotracheal atomizer at and below the vocal cords immediately prior to intubation, or lidocaine 1 to 1.5 mg/kg IV two to five minutes prior to extubation [76-78].

•Administer a positive pressure breath while extubating awake, to force secretions away from the vocal cords, and to abduct vocal cords.

●Treatment – Treatment of laryngospasm during emergence depends on the severity of the episode. Initial treatment includes administration of 100 percent oxygen by face mask, with gentle positive pressure ventilation. A small dose of propofol (0.25 to 0.8 mg/kg IV) may reverse laryngospasm in this setting [79,80]. For severe laryngospasm unresponsive to these maneuvers, succinylcholine should be administered (succinylcholine 0.25 to 0.5 mg/kg IV; if bradycardia occurs, atropine 0.02 mg/kg IV). Once laryngospasm breaks, the airway must be supported with mask ventilation, and if necessary, intubation.  

●Postanesthesia care – If laryngospasm is recognized and relieved quickly, in most cases no special post-anesthesia care is required. However, postoperative oxygen desaturation should be evaluated with auscultation of the chest and a chest radiograph to rule out negative pressure pulmonary edema (NPPE). This complication occurs more commonly in older children and adults, who can develop more forceful inspiration against closed vocal cords, than in young children. (See "Overview of the management of postoperative pulmonary complications", section on 'Pulmonary edema'.)

Patients should be monitored in the PACU for two or more hours after an episode of severe laryngospasm. If NPPE occurs, a longer period of observation or overnight hospital admission may be required to allow time for resolution.  

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Muscular dystrophy" and "Society guideline links: Pediatric anesthesia".)

SUMMARY AND RECOMMENDATIONS

●Preoperative evaluation and preparation – All children should be evaluated with a preanesthesia medical history, review of systems, and an anesthesia directed physical examination (table 1 and table 2). Preoperative preparation should include patient and parent or caregiver education and measures to reduce anxiety. (See 'Patient and parent or caregiver preparation for anesthesia' above.)

We routinely administer a premedication prior to anesthesia for pediatric patients, and usually administer midazolam 0.25 to 0.5 mg/kg orally, maximum 10 to 15 mg. (See 'Patient and parent or caregiver preparation for anesthesia' above.)

●Induction – Inhalation induction, with administration of anesthetic gas by face mask, is the most common induction technique in young children. Intravenous induction may be preferred for patients with obesity, high risk of aspiration, and the need for malignant hyperthermia precautions. (See 'Choice of induction technique' above.)

•Inhalation induction occurs more rapidly in children than in adults because of differences in pulmonary and cardiac physiology. Children are at risk for bradycardia and hypotension with administration of high doses of inhalation anesthetics during induction. (See 'Pediatric physiology and inhalation induction' above.)

•Sevoflurane is the most commonly used inhalation induction agent in the United States, and is administered with or without nitrous oxide. It provides a rapid onset, and is less pungent and irritating to the airway than other potent inhalation agents. (See 'Inhaled anesthetics for induction' above.)

•Propofol (up to 3 mg/kg IV) is used for intravenous induction for most healthy children. In general, children have a higher volume of distribution for intravenous medications than adults, and require higher initial doses for clinical effect. (See 'IV induction' above.)

●Laryngospasm – Laryngospasm occurs more commonly in children than in adults, and can occur during induction, maintenance, or emergence from anesthesia. (See 'Laryngospasm' above.)

The most important preventive measure is avoidance of airway manipulation during light anesthesia. Treatment includes administration of 100 percent oxygen by continuous positive airway pressure, deepened anesthesia, and if necessary, administration of succinylcholine (algorithm 1).

●Intravenous fluid – Isotonic crystalloid intravenous solutions should be administered to pediatric patients intraoperatively. Hypotension in healthy pediatric patients is often fluid responsive, with a 10 to 20 mL/kg bolus of normal saline or Ringer's lactate. (See 'Fluid management' above.)

●Intraoperative ventilation

•The goal for oxygen saturation for neonates is lower than for older children and adults (90 to 94 versus >95 percent), and the fraction of inspired concentration of oxygen should be set accordingly. Ventilation should be set to maintain end tidal carbon dioxide (ETCO₂) between 35 and 40 mmHg. (See 'Ventilation' above.)

•Minute ventilation and oxygen consumption are markedly higher in infants than in older children and adults (table 7). This means that neonates and small infants desaturate quickly during apnea, and there is less time to take corrective action.

●Maintaining normothermia – Maintenance of intraoperative normothermia is especially important in small children. Radiant heat lamps, forced air or heating blankets, and warm blankets may be used before and during anesthesia. (See 'Temperature control' above.)

●Regional anesthesia – Regional anesthesia is increasingly used for anesthesia and analgesia, and is usually performed after induction of anesthesia. (See 'Regional anesthesia' above.)

●Emergence and extubation – At the conclusion of anesthesia, the supraglottic airway or endotracheal tube should be removed once the patient is awake, or at a deep level of anesthesia, but should not be removed during the excitement stage of anesthesia (ie, Stage II), to avoid laryngospasm. (See 'Emergence laryngospasm' above.)

We extubate most patients awake, and remove SGAs during deep anesthesia. (See 'Deep versus awake extubation' above and 'Deep versus awake removal of SGA' above.)