40

Anesthesia for Patients With Clefts

Franklyn P. Cladis, Daniela Damian

Historically, the repair of cleft lip and palate was performed with no anesthesia.¹ The early repair of a cleft lip and palate consisted of reapproximating pared tissue edges. These procedures were simple and quick and were performed on older children or adults who could tolerate the pain and inconvenience of the procedure. At most, patients were allowed to gargle with ice water to produce local numbing. It was not until 1847 when John Snow described using ether for a cleft lip repair. In 1850 chloroform was reported for the repair of a bilateral lip and palate in a 7 year old.¹

Today these anesthetics would be considered rather rudimentary and potentially unsafe. The airway was unprotected and compromised because of blood drainage into the posterior pharynx. A refinement in airway management came with the introduction of the nasopharyngeal insufflation technique. A rubber tube was placed down each nostril, one for inspiration of anesthetics and the other for expiration. Packing could then be applied to the posterior pharynx, which provided a barrier for blood and protected the airway. In 1921 Magill provided the first endotracheal insufflation technique on an infant, and he later applied this technique for the repair of a cleft palate in 1924.1 Today general anesthesia is routinely and safely used for infants and children having cleft lip or palate repairs. Anesthesia management for these patients begins with a preoperative history and physical exam.

PREOPERATIVE CONSIDERATIONS

Children may present for surgical correction of cleft lip and palate at any time from infancy to early adulthood. Typically, surgical repair of the cleft lip is performed at 3 to 6 months and the repair of the cleft palate at 9 to 18 months. Pharyngoplasty, when necessary, is usually performed later at 5 to 15 years of age. Historically, the safe age for cleft lip repair was established at 6 to 12 weeks in 1964 by an audit of American plastic surgeons and later supported in 1966 by a large retrospective review that showed an increased rate of complications in children who weighed less than 10 pounds, had a hemoglobin lower than 10 g/dl, and had white cell counts higher then 10,000.^2,3 More recent studies have highlighted the safety of anesthesia for full-term and preterm neonates.^4,5 The authors in these studies have stressed the importance of having a team of surgeons, anesthesiologists, and nursing staff who are experienced and comfortable with the intraoperative and postoperative care of neonates. The preoperative preparation of an infant for cleft lip and palate surgery begins with a sound understanding of their anatomy, physiology, and associated anomalies.

A hallmark of developmental cardiac physiology is the transition from fetal to neonatal circulation. This transition is characterized by a change from parallel circulation (cardiac output contributes to both pulmonary and systemic perfusion simultaneously, allowing mixing of oxygenated and deoxygenated blood) to one that occurs in series (cardiac output contributes to either pulmonary or systemic perfusion with minimal admixture). This change occurs during delivery when pulmonary vascular resistance (PVR) decreases and systemic vascular resistance (SVR) increases, allowing for a significant increase in pulmonary blood flow. With a decrease in PVR, pulmonary blood flow and venous return to the left atrium increase. The increase in left atrial pressure and flow closes the foramen ovale. Over the next few months of life, pulmonary vascular resistance decreases even further, and the functional closure of the ductus and foramen ovale becomes essentially permanent.⁵

In the newborn period, an increase in PVR can lead to a return to fetal circulation, with right-to-left shunting across the foramen ovale and ductus arteriosus. Hypoxia and acidosis are important causes of an increase in PVR. Hypoxemia and acidosis can lead to a vicious cycle of increased PVR, increased right-to-left shunting, increased hypoxemia, increased tissue acidosis, and further increase in PVR and shunting.

The neonatal myocardium is immature and continues its development after birth. At delivery and extending into the neonatal period, fewer contractile elements and less elastin in the newborn’s myocardium result in a decreased contractile capacity and decreased ventricular compliance, respectively. The consequence is a reduced capacity to adapt to increases in preload or afterload.^6,7 Because the neonatal heart has a limited ability to increase stroke volume, neonates are poorly tolerant of bradycardia; moreover, significant volume loads may more easily cause ventricular overload and failure.⁷

Neonatal and infant lungs are less compliant than adult lungs. Immature lungs in pediatric patients are characterized by small and poorly developed alveoli with thickened walls and decreased elastin. Because infants (much like older adults) have less elastin, the closing capacity (the lung volume at which the alveoli collapse) occurs at a larger lung volume in the very young and the very old.^8,9 The neonatal chest wall is more cartilaginous and compliant than the adult chest wall, making it more likely to collapse. These developmental differences in respiratory physiology make the infant alveoli more prone to closure at end exhalation (closing capacity is larger than functional residual capacity), increasing the infant’s risk of developing atelectasis, right-to-left transpulmonary shunting, and hypoxia.

Another significant difference between neonatal and adult respiration is oxygen consumption. Neonatal oxygen consumption is two to three times greater than that of adults (5 to 8 ml/kg/min versus 2 to 3 ml/kg/min).10 This accounts for the rapid oxygen desaturation during apnea or hypoventilation.

Caring for an infant who was premature at birth can pose significant anesthetic concerns. Neonates, especially when they were born prematurely, may have episodes of apnea after exposure to sedation or general anesthesia.¹¹ The risk of an undetected, untreated apneic event must be balanced with the need for the patient to eventually return home. The younger the postconceptual age (PCA; gestational age [weeks] + age of baby [weeks]), the greater the risk for postoperative apneas, and the longer the duration of disordered breathing postoperatively.¹² Fixed risk factors include a history of extreme prematurity (28 weeks versus 32 weeks) and anemia (hematocrit less than 30%), regardless of current PCA.^13,14 It is not clear at what PCA a full-term or premature infant ceases to require postoperative monitoring for these events. In general, a PCA of more than 45 to 50 weeks may qualify an otherwise healthy once-premature infant to return home the day of surgery. Children’s hospitals have predetermined ages at which a premature baby having general anesthesia must be admitted overnight for observation. Infants considered at risk for postoperative apnea should be monitored overnight with a bradycardia and apnea monitor.¹⁴

Acute upper respiratory tract infections increase the incidence of perioperative pulmonary complications, which include laryngospasm, bronchospasm, and oxygen desaturation. Factors that increase the risk of these pulmonary complications include prematurity at birth, reactive airway disease, age younger than 12 months, airway procedures, endotracheal intubation, and exposure to secondhand smoke. Patients who are having cleft surgery often exhibit many of these risk factors. Infants with fever, change in behavior from baseline, purulent nasal drainage, and abnormal breath sounds likely have a moderate to severe upper respiratory tract infection and should have their surgery delayed 2 to 6 weeks.¹⁵

Many anomalies and syndromes have been associated with facial clefting. In a recent epidemiologic study of nearly 6 million births, almost 30% of cleft lips and palates occurred with an associated anomaly or syndrome. Associated congenital malformations involved most organ systems but primarily affected the cardiovascular, musculoskeletal, and central nervous system.¹⁶ Musculoskeletal deformities were the most common and included Polydactyly and limb reduction. Most central nervous system pathologies are categorized as “reduction deformities of the brain.” Cardiovascular defects were the third most common associated anomaly and primarily included ventricular and atrial septal defects and tetralogy of Fallot. Syndromes that are commonly associated with cleft lip and palate and their anesthetic implications are listed in Table 40-1. The three most common syndromes and sequences are Pierre Robin sequence, velocardiofacial syndrome (VCFS), and Stickler syndrome.

Other important issues to be considered with these preoperative patients are related to swallowing difficulties, which can lead to malnutrition, anemia, failure to thrive, frequent aspiration, and pulmonary infections. Ideally, the nutritional status of the child should be optimized before surgery because of the impact on wound healing and outcome. Significant bleeding from cleft surgery requiring transfusion has been described, but this is primarily presented in the older literature.¹⁷ In more recent retrospective evaluations of complications from cleft surgery, bleeding requiring transfusion is a rare event.^4,18,19

The preoperative evaluation of a cleft patient should include a complete history focusing on significant past medical (recent upper respiratory tract infections, obstructive symptoms such as snoring or apnea, vomiting), surgical, and family history, including associated anomalies and syndromes. The examination should identify hidden pathology such as heart murmurs and difficult airways. The airway exam in an infant is challenging. An abnormality in the craniofacial skeleton or mandible may predict difficulty with ventilation or intubation. The infant should be examined en face and in profile to identify facial anomalies and retrognathia. Associated anomalies may alter the anesthetic management of patients with clefts (see Table 40-1). A thorough preoperative evaluation may also include echocardiography and brain imaging in

ANESTHETIC MANAGEMENT

Premedication

Preoperative anxiety is common and can cause adverse effects extending into the postoperative period. Children who display significant preoperative anxiety are more likely to develop postoperative behavioral changes. These changes are characterized by an increase in separation anxiety, eating disturbances, sleeping disturbances, and oppositional defiant behavior and may last for 2 weeks. However, in one study they were significantly reduced with the preoperative administration of midazolam.²⁰ Preoperative anxiety in children is intimately linked to separation anxiety that usually begins to develop after 10 months of age. Most patients present for cleft surgery when they are less than 12 months old and often do not require premedication for preoperative anxiety. It should be considered in patients older than 10 months of age who exhibit preoperative anxiety. Patients with significant airway obstruction (as in Treacher Collins syndrome, Pierre Robin sequence, and obstructive sleep apnea) should have the dose of midazolam reduced or should not receive it at all.

Induction

Most patients with a cleft lip or palate can be induced with an inhaled anesthetic like sevoflurane. If an intravenous catheter is in place, an intravenous induction can also be performed. The most important issue related to induction of anesthesia is airway management. Airway management for most of these children is straightforward. Airway obstruction can usually be managed with the insertion of an oropharyngeal airway and continuous positive airway pressure (CPAP). Difficulty with mask ventilation or intubation can occur in infants with craniofacial anomalies or patients with retrognathia.

Difficult laryngoscopy is common in patients with isolated cleft lip and palate. Several studies have evaluated this, and the reported overall incidence of difficult laryngoscopy (such as the Cormack and Lehane 3 and 4 view) varies from 4% to 7%.^21,22 Factors predicting a more difficult laryngoscopic view include bilateral clefts and retrognathia. Age younger than 6 months was not a consistent risk factor. The patients in one study did not receive muscle relaxants, and they all received external laryngeal compression, which may explain some of the differences. Despite this high percentage of poor laryngoscopic view, only 1% of the patients were difficult to intubate, and only one patient had a failed intubation.^21,22

Ventilation or intubation may be difficult in patients with a cleft with associated craniofacial anomalies or retrognathia. In these patients, preparations for alternative airway management need to be made. If general anesthesia is induced, the patient should remain spontaneously ventilating until the trachea is secured with an endotracheal tube (ETT). Successful intubation through a laryngeal mask airway (LMA) with the aid of a fiberoptic scope has been described for pediatric patients with difficult airways.^23,24 The technique involves placing a fiberoptic scope, previously loaded with an ETT, through the properly positioned LMA. The scope is then used as a guide to pass the endotracheal tube into the trachea. Another endotracheal tube of equal size can be connected and act as a “pusher,” allowing advancement of the first endotracheal tube and facilitating LMA removal. Uncuffed ETTs are easier to use because the bulb for the cuff is difficult to pass through the lumen of the smaller LMAs (an ETT-LMA sizing chart is provided in Tables 40-2 and 40-3). The introduction of the Air-Q LMA has made this process easier (Fig. 40-1). The Air-Q LMA has a removable airway connector that allows an appropriately sized cuffed ETT with its pilot balloon to pass through the lumen. The ETT can be introduced over a fiberoptic scope. A “pusher” is provided with the LMA to facilitate its removal. The smallest size (size 1) can be used in an infant less than 7 kg. Other intubating devices include the Shikani Optical Stylet and the glidescope.25,26 Of note, disruption of a previous cleft palate repair during the placement of an LMA has been described; an LMA should be placed carefully in a patient with a history of cleft palate repair.²⁷

Table 40-2 Laryngeal Mask Airway–Endotracheal Tube Compatibility (Standard LMA)*

LMA Size	Endotracheal Size
1.5	4.0 uncuffed
2.0	4.5-5.0 uncuffed
2.5	5.5 uncuffed
3.0	6.0 uncuffed
4.0	6.0 cuffed

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