A 21-month-old boy with CHARGE syndrome was brought to the operating room for a gastroscopy, echocardiogram, auditory brainstem response (ABR) test, ear tubes and examination of his airway under general anesthesia. His past medical and surgical history included tracheobronchomalacia, left choanal atresia, a tracheoesophageal fistula (TOF) repair at age 2 days, and insertion of a percutaneous endoscopic gastrostomy (PEG). From his past anesthetic record, it was noted that he was difficult to perform bag-mask-ventilation (BMV) and that the use of an extraglottic airway device (EGD) did not improve ventilation of the lungs. It was also found that direct laryngoscopy (DL) and tracheal intubation were becoming increasingly difficult with successive procedures. The child was assessed preoperatively and it was reported that he remained clinically unchanged since the previous anesthetic 1 year ago.
After induction with sevoflurane and oxygen, an intravenous cannula was placed, and satisfactory ventilation and oxygenation were maintained with BMV and 20 cm H2O continuous positive airway pressure (CPAP). An initial attempt at tracheal intubation under DL with a Miller laryngoscope revealed a Cormack–Lehane Grade 3 view. Tracheal intubation was unsuccessful. BMV then became impossible. A further attempt at tracheal intubation was also unsuccessful.
Rigid bronchoscopy was rapidly performed by an ENT surgeon in an attempt to establish an airway, but this did not provide adequate oxygenation to the patient. The resulting hypoxemia caused severe bradycardia leading to cardiac arrest which required 15 minutes of cardiopulmonary resuscitation (CPR). A needle tracheotomy was also attempted and failed. This was followed by an urgent surgical tracheotomy by a surgeon, which was successful at establishing an airway and adequate oxygenation.
The tracheotomy consisted of a longitudinal midline scalpel incision through skin and subcutaneous tissue. Very little blood loss occurred and this was attributed to the cardiac arrest. The midline dissection continued down to the trachea and a midline cut was performed through approximately three tracheal rings providing sufficient space to advance a tracheal tube under direct vision.
All planned procedures were postponed and the child was transferred to the Pediatric Intensive Care Unit. He was cooled and remained sedated for 48 hours, after which he was allowed to wake up. His neurological function was returned to his baseline preoperative state.
CHARGE syndrome involves multiple congenital anomalies that can be life threatening. The acronym CHARGE stands for Colobomas of the eye, Heart disease, Atresia of the choanae, Retarded growth or central nervous system anomalies, Genital anomalies or hypogonadism, and Ear anomalies or deafness.
Features have been further divided into major and minor criteria of the CHARGE syndrome. Major include the classic 4Cs (Choanal atresia, Coloboma, Characteristic ear, and Cranial nerve anomalies). Minor criteria include cardiovascular malformations, genital hypoplasia, cleft lip and palate, TOF, distinctive CHARGE facies (Figure 49–1), growth deficiency, and developmental delay. The clinical diagnosis is based on the presence of four of the seven features described by the acronym, including at least one major anomaly. None of the components of the CHARGE association are universally present. Occasional associations include renal anomalies (duplex system, vesicoureteral reflux), spinal anomalies, scoliosis, osteoporosis, hand, neck, and shoulder anomalies.
CHARGE syndrome is regarded as one of the more common genetic disorders with a birth incidence of up to 1 in 8500.1 The syndrome involves a midline developmental defect which is thought to arise as a result of embryological arrest during a critical stage of early organogenesis in the second month of gestation.
The genetic basis of the condition remains undiagnosed in one-third of patients, but the remaining two-thirds have heterozygous mutations of the CHD7 gene on the 8q12 chromosome. This genetic involvement supports the term “syndrome” rather than “association” for CHARGE.2 Antenatal suspicion of the condition may arise from ultrasound identification of intrauterine growth retardation, polyhydramnios, and anomalies of the brain and heart. Diagnosis may occur when a neonate presents with feeding difficulties and obstructive sleep apnea.
Given the broad spectrum of disease associated with CHARGE syndrome, multiple life-threatening conditions can arise throughout life. In the neonatal period, bilateral choanal atresia, complex cardiac disease, esophageal atresia, severe T-cell deficiency, and brain anomalies can cause death in children who have CHARGE syndrome. In childhood and adolescence, swallowing problems, gastroesophageal reflux, respiratory aspiration, and postoperative airway events contribute to postneonatal mortality.3
Anesthesia for patients with CHARGE syndrome is associated with significant risk. Difficulty with airway management may arise at multiple levels and tends to increase in severity with age, giving false security from a past anesthetic history with successful airway management. BMV can be complicated in the presence of micrognathia and midface hypoplasia due to poor mask seal around the face and inability to support a patent airway. Airway narrowing is the main cause of difficult ventilation, and children with a collapsible upper airway (similar tolaryngomalacia) may require administration of CPAP during BMV to stent the airway open, and to increase functional residual capacity.
Choanal atresia and stenosis, if bilateral, can cause severe airway obstruction and cyanosis when the mouth is closed. Prior to surgical correction during anesthesia, it is essential to establish an open oral airway. This may require repositioning the patient, an oropharyngeal airway, an EGD, or tracheal intubation. Modified “awake” intubation with an EGD is one technique to overcome this problem.4 Early intervention with a tracheotomy is recommended for these patients to prevent frequent hypoxic episodes. Ventilating the lungs through an EGD may also be difficult due to laryngomalacia and tracheomalacia. Distal airway collapse may result in increased airway resistance, causing ventilation pressures to exceed the airway leak pressure of the EGD. This may lead to gastric insufflation.
Micrognathia is associated with difficult DL and difficult tracheal intubation (DI). Presence of a cleft palate is not associated with increased risk of difficult DL or DI. Although there are no specific protective effects from cleft palates during airway management, cleft palates may provide wider nasopharyngeal air spaces. This space may improve drainage of secretions in those children suffering from cranial nerve dysfunction, poor swallowing, and gastroesophageal reflux. It is also possible that the wider nasopharyngeal space may create a larger anatomical space to help accommodate EGDs.
It is essential that children with complex airway problems like CHARGE syndrome are managed in specialist pediatric hospitals. Practitioners responsible for these patients should be expert and experienced in the techniques required for their care. Specialist units should include multidisciplinary teams who work together regularly.
An airway plan helps to formulate strategies to cope with unexpected events: equipment and expertise are assembled to match those strategies. All staff should be briefed preoperatively about the details of the plan and individuals need to be clear about their roles in the overall strategy of patient care. This would occur preoperatively during the team briefing and WHO Time Out. Various guidelines have been designed for the difficult pediatric airway.5,6
The management of airway obstruction during pediatric anesthesia depends on the etiology. Weiss and Engelhardt7 differentiate airway obstruction into two categories: functional and anatomical/mechanical airway obstructions.
Functional airway obstructions include insufficient anesthesia (rectified by deepening anesthesia with volatile or intravenous agents), laryngospasm (treated with a muscle relaxant), opioid-induced muscle rigidity (treated with a muscle relaxant), and bronchospasm (treated with epinephrine). For an unexpected difficult pediatric airway in a healthy child, mask ventilation will improve with muscle relaxation.
While muscle relaxants can be beneficial for many patients with functional airway obstruction, patients with distal airway obstruction, including tracheomalacia and mediastinal masses, should not be paralyzed. If these patients are paralyzed, extrinsic airway compression may be exacerbated, diaphragmatic movement is eliminated, leading to large airway compression and a reduction in expiratory flow rates.
Anatomical or mechanical obstructions include poor BMV technique, obstruction secondary to large tonsils (pharyngeal, adenoid, and lingual), obesity associated with obstructive sleep apnea, foreign bodies, regurgitated gastric contents, vomit, secretions, blood, and other unknown reasons. The treatment of these problems is mechanical. The obstruction is usually resolved by basic airway maneuvers including jaw thrust, repositioning of the head, and optimum BMV technique with a two-handed/two-person approach. Airway adjuncts, including oropharyngeal airways and EGDs, are essential items to help relieve upper airway obstruction. Oropharyngeal obstruction may benefit from suction under direct vision, or tracheal intubation.
A review of airway maneuvers in pediatric anesthesia emphasized the value of jaw thrust to determine the depth of anesthesia and to restore airway patency for patients with or without tonsillar hypertrophy. Jaw thrust was found to improve minute ventilation more than chin lift alone or chin lift with CPAP. A combination of jaw thrust and CPAP increased glottic opening and increased minute ventilation.8
An awake intubation technique in children is usually impractical due to poor patient cooperation; however, variants of this technique can be used in neonates and infants. Awake intubation of a neonate with a predicted difficult airway using an EGD is a safe technique for early establishment of an airway. This technique avoids hypoxemia during induction of anesthesia and has been successfully used in patients with Pierre Robin syndrome and Treacher Collins syndrome.9 Following application of local anesthetic, the EGD is inserted and the neonate then receives a gas induction, followed by tracheal intubation through the EGD with an ultrathin flexible bronchoscope and an appropriate size endotracheal tube (ETT).4
EGDs have multiple applications in the management of pediatric patients with difficult airways. They can be used as a primary airway, a conduit for tracheal intubation, a rescue ventilation device during resuscitation, and for rescue during a failed airway. These devices can be used for extended periods of time for various surgical and medical indications.10
Absolute contraindications to EGD use include any patient with an increased risk of pulmonary aspiration, airway obstructions beyond the glottis, and the need to ventilate the lungs at high airway pressures. Relative contraindications include a partially collapsible lower airway, restricted access to the airway, and inexperience using an EGD.11
Although the incidence of difficult DL is lower in children than in adults (1.37% vs. 9%), the incidence of difficult DL in infants is significantly higher than in older children (4.7% vs. 0.7%).11 The incidence of difficult DL is doubled in children undergoing cardiac anesthesia, due to the relatively high incidence of concomitant congenital syndromes such as CHARGE syndrome.12 Difficulty with intubation can change as the child matures. Children with CHARGE syndrome and Treacher Collins syndrome become more difficult to intubate with increasing age, whereas those with Pierre Robin syndrome become easier with age.13
DL and tracheal intubation, aided by a tracheal introducer (commonly known as a “bougie”) and optimum external laryngeal manipulation, can be successful in the hands of experienced practitioners. For example, straight blade paraglossal approach with a bougie was successful for infants with Pierre Robin syndrome.14 In the event of failure with DL, alternative options need to be available, including rigid bronchoscopy, flexible bronchoscopy, optical stylet, video-laryngoscopy, or surgical airway.
Prolonged intubation attempts are associated with hypoxemia and patient awareness. hypoxemia can be avoided by using denitrogenation and nasal apneic oxygenation.15 Intubation should be limited to three attempts or less to minimize the risk of trauma and other adverse events. Small tracheal tubes should be available for unexpected subglottic tracheal stenosis. Video-laryngoscopes are useful devices for tracheal intubation in children, as are optical stylets, rigid and flexible bronchoscopes.
The inability to intubate and oxygenate a child can rapidly lead to life-threatening hypoxemia. Lung modeling from Hardman and Wills16 using the Nottingham Physiology simulator shows that young children become hypoxemic during apnea earlier than adults; the younger the child, the faster the onset of hypoxemia. Unless airway obstruction is quickly reversed, tissue hypoxia ensues, leading to cardiac arrest. Cardiac arrest in neonates is associated with 72% mortality.
Numerous barriers have been identified which interfere with reoxygenation through front of neck access (FONA) and potentially lead to lethal delays.
Delays performing FONA can be attributed to organizational and human failures. Inadequate training, supervision, support, and equipment need to be addressed at an organizational level.
Suboptimal treatment can result from human factor failings, and include fixation errors, poor communication, distorted situation awareness, inadequate team work and poor leadership, task management, and decision making (see Chapter 6).
Management of a CICO crisis may be required only once in an anesthesia practitioner’s career. Performing under these circumstances is likely to be an extremely stressful event. Such stress can cause adverse physiological changes to the practitioner, including loss of fine and complex motor skill, cognitive deterioration, perceptual narrowing, and a state of hypervigilance.17 To cope with this stress and rarity, regular training and preparation is required. Ideally, training should take place under simulated stressful conditions and involve other team members. Training to a specific standard operating procedure reduces choice, improves reaction time, and helps to decrease the signs and symptoms of extreme stress.
Related posts:
Direct Laryngoscopy
Airway Management of a Morbidly Obese Patient Suffering from a Cardiac Arrest
Management of Extubation of a Patient Following a Prolonged Period of Mechanical Ventilation
Airway Management of an Uncooperative Down Syndrome Patient with an Upper GI Bleed
Airway Management in Penetrating Neck Injury
Appendicitis in Pregnancy
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