Pediatric Anesthesia: A Guide for the Non-Pediatric Anesthesia Provider Part II

By Bentham Science Publishers

Pediatric Anesthesia: A Guide for the Non-Pediatric Anesthesia is a comprehensive, contemporary reference that addresses all aspects of pediatric anesthesia. Both students and medical practitioners – novice and experienced - will find invaluable educational and practical information in this book. The book covers the subject in two parts.
Part I covers basic information about pediatric and neonatal anatomy and physiology, pharmacology, emergency room and operating room procedures and surgery. Chapters on general anesthetic procedures in emergency rooms, operational theatres and common surgeries.
Part II covers advanced topics for practicing healthcare professionals which include anesthesia for patients with a range of common and uncommon comorbidities, considerations for critically-ill patients, genetic disorders, pain management, COVID-19 guidelines for anesthesia, patient safety and research.
Key features:
- Basic and advanced information about pediatric and neonatal anesthesia covered in 25 chapters over two parts
- Simple and organized presentation for learners
- Contributions by expert clinicians and researchers
- Special topics included such as considerations for patients with comorbidities and genetic disorders
- References for further reading
- Detailed illustrations and tables
The text is an essential reference for scholars and professionals affiliated with general anesthesiology and surgery specialties at all levels who want to understand anesthesia for pediatric patients.

• Language: English
• Publisher: Bentham Science Publishers
• Release date: Nov 29, 2001
• ISBN: 9789815036213

Book preview

Anesthesia for Pediatric Patients with Common Comorbidities Part I

Divya Dixit, M.D.¹, *, Dinesh K. Choudhry²

¹ Department of Anesthesia and Perioperative Medicine, Alfred I. duPont Hospital for Children, Wilmington, DE, USA

² Department of Anesthesiology, Shriners Hospital for Children, Philadelphia, PA, USA

Abstract

Children undergoing anesthesia have many considerations of disease processes that require careful attention to details and addressing specific needs. There are several comorbidities that are frequently encountered in a pediatric setting. A common scenario is a child with an upper respiratory tract infection presenting for elective surgery. We will discuss the criteria to be considered regarding when it is safe to proceed with elective surgery and when the risk is high. Asthma is common among children, and exacerbation can occur during an anesthetic. Anesthetic management of children with these respiratory illnesses is discussed. Children with Down syndrome frequently present for various cardiac and non-cardiac surgical interventions. Anesthetic issues relating to their non-cardiac surgeries will be discussed. Children with sickle cell disease is yet another group of patients frequently admitted to the hospital with sickle cell crisis. They warrant attention to specific details to ensure getting through surgery safely and require optimal pain management. Obstructive sleep apnea is increasingly encountered in children presenting for surgical procedures. Anesthetic challenges and risks they pose will be discussed.

Keywords: Acute chest syndrome, Apnea-hypopnea index, Asthma, Bronchospasm, Central sleep apnea, Cervical spine instability, Deep extubation, Down syndrome, Hemoglobin F, Laryngeal mask airway, Laryngospasm, Obstructive sleep apnea, Perioperative respiratory adverse events, Red blood cell transfusion, Short-acting beta2 agonist, Sickle cell disease, Sleep-disordered breathing, Upper respiratory tract infection, Vaso-occlusive crisis, Wheezing.

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* Corresponding author Bharathi Gourkanti: Department of Anesthesiology, Cooper Medical School of Rowan University, Cooper University Health Care, Camden, NJ, United States; E-mail: [e-mail]

UPPER RESPIRATORY TRACT INFECTION

Introduction

Upper respiratory tract infection (URI), the common cold, refers to infection limited to the upper respiratory tract airway and involves a runny nose, nasal congestion, cough, sneezing, sore throat, wheezing, low-grade fever and malaise as presenting symptoms. Most adults in the United States experience 2 to 4 URIs per year, while youngest children experience 6 to 8 episodes per year [1]. Ninety-five percent of URIs are secondary to acute viral causes, of which rhinovirus with >100 serotypes accounts for a large majority, 30%-50% [2]. Preschool children attending large daycare centers were reported to have more colds than children at home [3].

In the Anaesthesia Practice In Children Observational Trial (APRICOT) study, a large prospective observational study of 30,874 children from birth to 15 years of age in 261 hospitals located across 33 European countries, the incidence of perioperative severe critical events was 5.2%. Respiratory critical events were the most frequent (3.1%) followed by critical cardiovascular events (1.9%) [4].

Perioperative Respiratory Adverse Events

Current or recent URI in children undergoing surgery poses a higher risk of perioperative respiratory adverse events (PRAEs), which include laryngospasm, bronchospasm, coughing, airway obstruction, breath-holding, and arterial hypoxemia [5, 6]. Significant respiratory complications, such as atelectasis, aspiration, post-intubation croup, stridor, and pneumonia could result in unanticipated tracheal intubation or re-intubation, return to the emergency department or unexpected hospital admission [4, 6]. Twice the usual length of stay in the hospital and higher costs were associated in a prospective study of children with PRAEs undergoing non-cardiac surgery [7]. Complications are generally mild and managed easily and safely [8, 9] and do not have long-term sequelae [6, 10, 11]. Few reports of children with URI undergoing surgery resulting in death were related to unsuspected myocarditis [12].

URIs are generally self-limiting, but airway hyperactivity can persist for 6-8 weeks with increased secretions, mucosal inflammation, and altered neural reflexes. Anesthetic risks are greatest in the first few days after a URI but remain increased for up to 6 weeks [13].

Risk Factors

The relative risk of PRAEs doubled for children who had symptoms of URI present or less than two weeks preceding surgery, particularly for laryngospasm [14]. The risk for PRAEs, however, was lower when URI symptoms were 2-4 weeks prior to procedures requiring anesthesia in this study. In the Pediatric Sedation Research Consortium database, 83,491 sedations were analyzed for complications. Risk of PRAEs was found to be greater than 22% in children undergoing procedural sedation with current URI with thick and/or green secretions [15]. A parental statement that the child has a ‘cold’ on the day of surgery is a good indicator of increased risk of PRAEs [16]. This study had eight variables associated with increased risk of PRAEs that included sputum production, nasal congestion, snoring, passive smoking, orotracheal intubation, choice of an induction agent, and whether muscle relaxant was reversed. With every additional year of age risk of occurrence of PRAEs decreased by about 8% in one study [11] and relative risk decreased by 11% in another [14]. Various factors that have been found to be associated with a greater risk of PRAEs are summarized in Table 1.

Table 1 Factors associated with increased risk of perioperative respiratory adverse events.

ASA = American Society of Anesthesiology

Preoperative Evaluation

Preoperative assessment begins with obtaining a thorough history. Special attention is given to the presence of current respiratory symptoms and those in the past 2-4 weeks. Symptoms, such as high fever (core body temperature higher than 100.4 °F or 38 °C) with dry or productive cough, clear or purulent nasal discharge, presence of wheezing, lethargy, poor oral intake, and general feeling of being unwell should be considered for postponement of surgery (Table 2). Risk factors, such as airway endoscopic procedure, the urgency of surgery, presence of asthma, age of the child, expertise of the anesthesiologist and parental social, economic and work considerations should be considered in making a decision to cancel elective surgery [5, 23, 24].

Physical examination should assess child for general appearance, temperature, runny nose, cough, chest auscultation for wheezing and crackles, stridor, intercostal retractions, and work of breathing. A child who appears ill and is in obvious distress is not a candidate for elective surgery.

Investigations

Investigations such as laboratory tests and radiography, have a limited role in evaluating an acute URI. A chest radiograph may be normal in the presence of clinical symptoms. Complete blood count with differential may not contribute much to the pre-anesthetic evaluation. Respiratory syncytial virus testing may be possible expeditiously in an infant during winter season for confirmation of diagnosis and avoidance of unexpected admission in the hospital intensive care unit (ICU) [25, 26].

Postponement of Elective Surgery

In children with mild symptoms such as rhinorrhea, with no fever and cough, proceeding with sedation or anesthesia is appropriate. The dilemma occurs when a child has evolving symptoms prior to surgery that are less than severe. Short ear, nose, and throat (ENT) procedures, such as bilateral myringotomy tubes (BMT) and adenotonsillectomy provide relief in symptoms of recurrent ear infections and sleep apnea and need to be weighed against cancellation. The decision by the anesthesiologist needs to be based on the individual history and presenting symptoms and should involve discussion with the surgical colleague. Also, it would be prudent to explain to the family the anticipated complications and document the same in the informed consent [12]. If the decision is made to reschedule surgery, the duration of postponement should be a minimum of 2-4 weeks to reduce the risk of PRAEs [6, 14]. It provides the child adequate time to recover from the current episode of illness but before the recurrence of another URI.

Table 2 Indicators for postponement of elective surgery.

Perioperative Management

Premedication

Premedication is widely used in children for separation anxiety. However, oral midazolam has been associated with an increased risk of respiratory complications by delaying awakening [14, 17] and altering the respiratory mechanics with a decrease in functional residual capacity [27]. It is, however, prudent to administer a sedative such as midazolam in these children.

Anesthetic Induction

Intravenous (IV) induction with propofol is preferable when compared with inhalational induction with sevoflurane [4]. In one study, children with ≥ 2 risk factors undergoing anesthesia with a supraglottic airway were more likely to experience PRAEs at induction with sevoflurane than IV propofol [28]. Thiopentone as an induction agent was associated with the highest probability of an adverse event followed by halothane and sevoflurane, and propofol was associated with the lowest probability in a study of 2051 children [16]. In children, however, it may not always be possible to obtain awake peripheral venous access; mask induction with sevoflurane is acceptable in such a situation.

Airway Device

In a child with URI, since the airway is hyper-reactive, it is advisable to minimize stimulation. Mask airway is the least stimulating, followed by supraglottic airway, and the endotracheal tube (ETT) placement is the most stimulating [6, 16, 17, 29]. A laryngeal mask airway (LMA) may be less stimulating but requires greater anesthetic depth. In one large study of more than 17,000 patients, the authors found that children with URI were four- to sevenfold more likely to have PRAEs, and the risk of respiratory complications was 11-fold higher in those children who had ETT compared with those who did not [5].

The risk of laryngospasm was high in children with three or more attempts at insertion of airway device compared to securing in one attempt and use of uncuffed tracheal tube than those with cuffed tracheal tube [14].

More than 60% of episodes of symptomatic URI among young children are complicated by acute otitis media and/or acute otitis media with effusion [30]. These children frequently present for short ENT procedures such as BMT; inhalation anesthesia via mask which is less stimulating, is appropriate with prompt IV placement should a complication such as laryngospasm or bronchospasm occur.

Emergence

Subhypnotic dose of propofol 0.5 mg/kg IV given prior to tracheal extubation reduces the occurrence of laryngospasm in children undergoing tonsillectomy with or without adenoidectomy [31]. At our institution, LMA is almost always removed in a deep plane of anesthesia and the patient transported to the recovery room with an oral airway in situ.

The risk of PRAEs remains in the recovery room, and children should be observed carefully with routine monitors, and oxygenation continued until awake. Upper airway obstruction should be managed with placement of oral or nasal airway (if appropriate), chin lift and jaw thrust. Placing children in the lateral position is preferred by some (post-tonsillectomy position); this facilitates drainage of secretions and maintenance of airway in the child still anesthetized after deep extubation [32, 33].

ASTHMA

Introduction

Asthma is a heterogeneous disease of the lower airways characterized by symptoms of persistent dry cough, dyspnea, wheezing, and chest tightness. The hallmark of asthma is inflammation of the airways with hyper-reactivity to stimuli leading to mucus secretion, bronchospasm, and recurrent airway obstruction. Airway remodeling can develop early in the course of disease with thickening of basement epithelium membrane and smooth muscle layer causing irreversible airway changes [34].

Reactive airway disease is a nonspecific term used in recent years, especially for pediatric patients who have symptoms of bronchospasm: wheezing, cough, and dyspnea. However, all of these children may not develop asthma later in life [35].

Asthma is a common childhood chronic disease and affects 6.7 million children in the United States [36]. Tucson Children's Respiratory Study was the largest longitudinal study in the United States studying the natural history of asthma from a cohort of more than 1200 newborns [37]. Three different phenotypes of asthma/wheezing have been identified: 1) transient wheezing in response to viral infections typically during first three years of life; 2) non-atopic wheezing beyond the first few years of life often due to viral infections and less likely to persist later; and 3) atopy-associated wheezing, which is immunoglobulin E (IgE) mediated hypersensitivity and persists into later life [38]. In this section, we discuss the complications and perioperative anesthetic management of the child with asthma.

Wheezing as a Risk Factor for PRAEs

Children with a history of wheezing are at increased risk of PRAEs. In a prospective cohort study in one institution, 9297 children undergoing general anesthesia were analyzed. Of these, 15% with positive respiratory history had PRAEs; 2% had bronchospasm, 4% laryngospasm, 4% airway obstruction, 10% oxygen desaturation (<95%), 7% coughing, and 1% stridor. Wheezing with exercise or more than 3 episodes of wheezing in the past 12 months was associated with a higher risk of perioperative bronchospasm compared to history of recent URI (< 2 weeks). Children with nocturnal dry cough had a very high risk of bronchospasm than those without. Personal history of eczema and hayfever had higher associated PRAEs/bronchospasm. The risk of bronchospasm increased with at least two family members with history of asthma, eczema, rhinitis, hayfever or if both parents were smokers [14].

Preoperative Evaluation

A detailed history is useful in assessing the severity and control of asthma prior to surgery. To ascertain optimization prior to surgery at our institution, questions asked from the caregiver are listed in Table 3. Clinical examination focuses on wheezing, auscultation for rhonchi, chest wall retraction and use of accessory muscles of respiration. Baseline preoperative pulse oximetry reading should also be obtained.

Table 3 Questionnaire for evaluation of asthma.

Investigations

Routine laboratory testing is generally not needed. Eosinophilia in the peripheral blood smear is simple to measure. Markers of atopy, total IgE levels, antigen-specific IgE antibodies, and skin prick tests are of limited value for evaluating allergies such as latex, mostly in the scenario of postoperative complication. In a study of 100 children, risk factors obtained from child and family history were good clinical predictors of PRAEs compared with immunological markers of allergic sensitization, which were poor predictors [21]. Investigations such as spirometry and peak expiratory flow (PEF) in older children may be useful to assess control of the illness. Forced expiratory volume in 1 second and ratio to forced vital capacity can differentiate between well-controlled and poorly controlled asthma.

During a severe asthma episode, arterial blood gas may be useful. Imaging studies are rarely indicated unless pulmonary infection, aspiration, atelectasis, pneumothorax or barotrauma is suspected. Chest radiograph may be useful intra-operatively in detecting the ETT position and atelectasis resulting from mucus plugging of the ETT.

Perioperative Management

Preoperative

For patients with a mild expiratory wheeze that resolves with cough or bronchodilator nebulizer treatment and is not associated with other symptoms of complicated URI, it is appropriate to proceed with the elective surgery. The following asthma medications should be continued until the day of surgery: short-acting beta2 agonist (SABA), inhaled or oral corticosteroids, leukotriene modifiers, anticholinergics (ipratropium bromide via metered-dose inhaler or nebulizer) and methylxanthines. Optimization prior to surgery for moderately controlled asthma may need additional inhaled corticosteroid and SABA one week before surgery. A course of oral corticosteroids 3-5 days prior to surgery may be necessary for poorly controlled asthma.

Premedication

Premedication with SABA in a child with mild wheezing is given via metered dose inhaler (MDI) to an older child or via nebulizer to a younger child 30 minutes prior to induction of anesthesia. Inhaled SABAs have a wide therapeutic window and fast peak onset in providing smooth muscle relaxation and bronchodilation with a beneficial effect on reflex bronchoconstriction in response to tracheal intubation [39]. The dose for MDI is 2-8 puffs, and albuterol nebulizer is 2.5-5 mg depending on the body weight of the child less than or more than 20 kg [40]. Midazolam premedication was associated with increased risk of desaturations and airway obstruction in one study [14]; however, in another study, it was found to be safe in asthmatics [41]. Anxiolysis with oral midazolam (0.5 mg/kg) is routinely used in our practice to prevent undue stress in a child with asthma.

Anesthetic Induction

Intravenous induction with propofol reduced risks of PRAEs compared with inhalational induction with sevouflurane in a randomized trial in children using LMA [28]. Propofol blunts the bronchospastic response to intubation in both asthmatic and non-asthmatic patients and is the IV induction of choice compared with etomidate and thiopental [42, 43]. It is considered to be safe in children with egg allergy if there is no history of anaphylaxis [44]. Ketamine administered intravenously is traditionally the agent of choice for induction in the asthmatic child for its direct bronchodilatory effect, especially if hemodynamic instability is present. It may, however, increase airway secretions and is given along with an anticholinergic agent that is beneficial in reducing secretions and decreases reflex bronchoconstriction by acting on muscarinic cholinergic airway receptors. Patients on chronic systemic corticosteroids should receive stress dose of hydrocortisone.

We do not routinely use intravenous lidocaine prior to intubation in children to prevent reflex bronchoconstriction as may be the practice in adults. Topical spraying of the airway with lidocaine can trigger airway reactivity and desaturations and is not standard practice [45].

Mask induction with sevoflurane or halothane (if available) is an acceptable option. Maintenance with sevoflurane, isoflurane, or halothane is acceptable as these volatile agents are potent bronchodilators. Desflurane is avoided as it is an irritant to the airways and may cause increased secretions, coughing, and laryngospasm [46, 47].

Airway Device

A supraglottic airway device, which is less invasive, is preferable to ETT in a child at risk of PRAEs. ETT was associated with breath-holding, laryngospasm, bronchospasm and major oxygen desaturation events (SpO2 < 90%) in a study [10]. Significantly greater PRAEs occurred in the ETT group compared with the LMA group, concluding that LMA offers a suitable alternative [10, 16]. Reactive airway disease was an independent risk factor for PRAEs in a study of 1078 children between the ages of 1 month to 18 years presenting for elective surgery. In this study, children less than 5 years of age with URI who received ETT had a greater incidence of respiratory events than those without URI, and infants less than 6 months of age had a higher incidence of bronchospasms than older children [6]. In a study of infants undergoing minor elective procedures, LMA use was associated with a lower occurrence of laryngospasm and bronchospasm than ETT [29]. Meta-analysis of LMA versus ETT in children with URI found LMA to be better in reducing cough, but there was no decrease in feared complications (de Carvalho, Vital et al. 2018).

However, if tracheal intubation is necessary, it is imperative that the airway is instrumented in a deep plane of anesthesia. Cuffed ETT, now widely prevalent in pediatric anesthesia practice [48] is associated with less leak around the cuff while allowing higher peak airway pressures during mechanical ventilation compared to uncuffed ETT. Also, cuffed ETT had a lower association with PRAEs, postoperative sore throat and hoarse voice [49]. In the APRICOT study, a large range of incidence of bronchospasm was observed across the 33 participating countries, 0.3 to 3.2%, with 96% of bronchospasm occurring in the operating room (awakening > induction > maintenance of anesthesia) compared to the PACU [4].

Ventilation Strategy During Anesthesia

To avoid air trapping and breath stacking in the child with asthma, increasing expiratory time with a low inspiratory - expiratory ratio and permissive hypercapnia are used. Low tidal volume and respiratory rate, and avoidance of excessive positive end-expiratory pressure (PEEP) and high peak airway pressures to avoid barotrauma are preferable. IV hydration and the use of humidified gases in the anesthesia circuit are appropriate.

Intraoperative Bronchospasm

Intraoperative bronchospasm presents with bilateral expiratory wheeze, reduced or absent chest movement and breath sounds, increased airway pressures, up-sloping or absent end-tidal CO2 (ETCO2) trace, increasing ETCO2, and decrea- sed arterial oxygen saturation/hypoxemia.

Management of bronchospasm under anesthesia includes the following:

Remove any triggering stimulus if applicable e.g. suctioning of ETT.

100% inspired oxygen, with gentle manual ventilation while allowing time for exhalation.

Deepen the anesthetic with either an inhalation agent or IV propofol.

Ketamine is frequently used in 0.5-1 mg/kg IV dose for its bronchodilator effect.

Rapidly acting albuterol puffs (8 -10) via ETT through an in-line adaptor. The puffs can be repeated in 5-10 minutes.

Epinephrine, when bronchospasm persists, may be given 0.5-1 mcg/kg IV incrementally as needed or 10 mcg/kg as a depot intramuscular (IM) or subcutaneous injection.

If anaphylaxis is suspected, epinephrine infusion may need to be initiated.

IV methylprednisolone 1-2 mg/kg, 125 mg maximum dose or hydrocortisone 2 mg/kg, 100 mg maximum dose even though onset is delayed (4- 6 hours).

In severe situation (status asthmaticus) the following additional measures may be considered

Neuromuscular blocking agent to facilitate chest wall movement

Escalation of care to IV terbutaline

Magnesium sulfate and theophylline use should prompt help from pediatric intensive care unit (PICU) physician

Heliox and extracorporeal membrane oxygenation therapy in critical condition

Medications that may Precipitate Bronchospasm

Medications that may cause histamine release should be used cautiously such as neuromuscular blocking agents, mivacurium and atracurium. The commonly used muscle relaxant rocuronium has been associated with intraoperative IgE-mediated allergic reactions. Sugammadex, a neuromuscular reversing agent that encapsulates the steroidal neuromuscular blocking agent, has been shown to have an association with bronchospasm and anaphylaxis [50]. Amongst opioids, morphine, in particular, can cause histamine release and precipitate bronchospasm.

Various causes of intraoperative bronchospasm that should be evaluated as treatment path is different from that of asthma as outlined in Table 4.

Table 4 Other common causes of intraoperative wheezing.

Emergence

Suctioning and removal of the LMA in a deep plane of anesthesia avoids stimulating an already irritable airway. The incidence of PRAEs was lower in children who were under deep anesthesia when LMA was removed and lower in those children who were awake when ETT was removed in the operating room [14]. However, deep extubation may result in airway obstruction requiring interventions.

Bronchodilator treatment with SABA may need to be repeated in the post-anesthesia care unit (PACU). Corticosteroid nebulizer and dexamethasone IV or oral may need to be administered every 6 hours for 24 hours after extubation. Persistent or recurrent wheezing or rhonchi, copious secretions, rising body temperature, and inability to maintain arterial oxygenation or continued requirement of supplemental oxygen warrants admission for further observation and treatment. If epinephrine has been required intra-operatively, there is a possibility of recurrence of bronchospasm once its effect wears off. At the time of discharge, the child should be able to maintain arterial oxygen saturation in room air, have no upper airway obstruction or stridor, and have a resolution of wheezing.

Conclusion

URI and asthma are major respiratory causes of perioperative complications in children undergoing surgery. Younger age group, higher ASA status, emergency surgery, limited pediatric expertise, airway instrumentation, and presence of multiple risk factors contribute to PRAEs. Though most events do not lead to mortality or long-term adversity, careful assessment and management based on principles described above could contribute to a good outcome.

DOWN SYNDROME

Down syndrome (DS) is a common congenital anomaly that is prevalent worldwide and frequently encountered in the pediatric population resulting from trisomy of chromosome 21. It is characterized by special morphological features and involvement of various organ systems that have relevance to the anesthetic management of these children. The incidence is about 1 in 800 live births, and about 95% occurrence is sporadic and non-familial due to disjunction (extra copy of chromosome 21 in every cell), and the remaining 5% are due to translocation and mosaicism [51]. The major risk factor for DS is advanced maternal age. Advanced paternal age combined with maternal age significantly influences the incidence of Down syndrome [52].

Due to the presence of numerous comorbidities, as described in Table 5, children with trisomy 21 have a higher frequency of complications associated with general anesthesia [53]. In this section, relevant anesthetic issues and perioperative management of children with DS is discussed.

Clinical Manifestations

Craniofacial Features

Children with DS have characteristic craniofacial features: microbrachycephalic head, short broad neck, upward slanting palpebral fissure, epicanthal folds, broad flat nose, small low set ears, large protruding furrowed tongue, and midface and mandibular hypoplasia (Fig. 1).

Fig. (1))

Photograph of a child with Down syndrome (photo used with parental permission).

Neurological Features

Mental retardation is commonly present in children with DS; it is usually mild to moderate but could be occasionally severe [54]. Hypotonia is present in nearly all children with Down syndrome [55].

Increased transverse ligament laxity and odontoid hypoplasia in children with DS results in higher incidence of atlantoaxial instability and an increased risk of C1-C2 subluxation with consequent neurological injury [56] (Fig. 2).

Respiratory System

Airway abnormalities associated with DS include subglottic stenosis, laryngomalacia, tracheomalacia, choanal atresia, cleft palate and lip, high arched narrow palate and pharyngeal muscle hypotonia. Airway obstruction and obstructive sleep apnea (OSA) is a common concern and is generally multifactorial due to a large protruding tongue, a small oral opening, midface hypoplasia, adenotonsillar and lingual tonsillar enlargement and obesity. Upper respiratory tract infections are frequent due to relative immune deficiency with consequent perioperative adverse events such as laryngospasm and arterial hypoxemia [57]. In one study, more than 50% of children with DS had polysomnography-confirmed OSA without any clinical symptoms [58]. In a study of 188 children with DS between 6 months and 6 years of age, moderate to severe OSA was found in 14%, and mild to moderate OSA was found in 59% of the children. Age, body mass index and tonsillar size did not predict OSA in this study [59].

Musculoskeletal

Ligamentous laxity and joint hypermobility lead to musculoskeletal presentations such as cervical spine instability (atlantoaxial is the most frequent), hip instability, patellar instability and foot deformities. Other associated orthopedic conditions include slipped capital femoral epiphysis, scoliosis and rarely, polyarticular arthropathy [60]. Ligamentous laxity of other joints such as thumb, fingers and elbow may also be present [61].

Cardiac Anomalies

Congenital heart disease is present in about 50% of infants born with DS; most of whom require surgery. Congenital cardiac lesions commonly seen are atrioventricular septal defect or atrioventricular canal defect (45%), ventricular septal defects (35%), and secundum atrial defects (8%). Patent ductus arteriosus (7%) and tetralogy of Fallot (4%) are less commonly associated. Mitral valve prolapse can occur in about 50% of adolescents and adults with DS [62].

Behavioral Issues

A pattern of developmental regression has been reported in individuals with DS with loss of language, behavioral, and cognitive skills previously acquired. This condition, recently referred to as Down syndrome disintegrative disorder (DSDD), if severe affects quality of life and autonomy [63]. Clinical features of DSDD include mood lability, social withdrawal, depression, anxiety, insomnia, catatonia, psychotic symptoms and anorexia. Aggression in individuals with DSDD may be directed towards self or others. Children with DS, therefore, are prone to anxiety and agitation in the stressful hospital setting. A separate room and calming presence of medical personnel and a parent, in conjunction with premedication may be helpful.

Other Conditions

The physical appearance in children with DS generally consists of short stature and obesity. These children also frequently have a single transverse palmar crease, fifth-finger clinodactyly, deep plantar groove between first and second toes, and excessive skin on the nape of the neck and Brushfield spots on the iris. Seizure disorders and hypothyroidism are frequently associated with DS.

Table 5 Common conditions associated with Down syndrome and their incidence.

Preoperative Evaluation

Common surgical procedures that these children present for are BMT, tonsillectomy and adenoidectomy, airway endoscopy, cataract surgery, repair of congenital heart defects and intestinal atresia repair and pull-through for Hirschsprung’s disease. In view of various organ systems involvement, a thorough history should be obtained and a physical examination performed (Table 5).

Cardiac Assessment

Cardiac assessment is essential and includes electrocardiogram (ECG) and echocardiogram to evaluate structure and function of the heart, severity of the lesion (repaired or unrepaired), and presence of intracardiac shunt. Eisenmenger’s syndrome with high pulmonary vascular resistance and reversal of shunt has a higher incidence in DS. Higher mean pulmonary artery pressure and increased frequency of pulmonary arterial hypertension are observed in children with DS [64]. This may be related to congenital heart disease or to chronic hypoxia from the obstructive airway, hypotonia and hypoventilation.

Neurological Evaluation

Neurological evaluation is essential before planned surgery. Preoperative radiological examination of the neck is not routinely recommended in all children with DS. The American Academy of Pediatrics recommends that children with neurological symptoms such as neck pain, weakness, spasticity, difficulty with gait, bowel issues, or bladder function should be further evaluated [51]. The neck radiograph images are obtained in neutral, flexion and extension positions. More than 5 mm distance between the posterior edge of the anterior arch of C1 and the anterior edge of dens (atlantodens interval) in lateral neck view is considered abnormal (Fig. 2). Further evaluation with computerized tomography (CT scan) and magnetic resonance imaging (MRI) is recommended (Fig. 3). Practice at our institution has shifted away from routine preoperative neck radiographs in all children older than 3-5 years of age and is performed if clinically indicated.

Fig. (2))

Lateral radiograph of neck in a child with Down syndrome showing cervical instability. A. View in flexion showing increased atlantodens interval B. View in extension leads to a decrease in atlantodens interval.

Fig. (3))

Down syndrome,