Neonatal Tracheostomy

Introduction

Tracheostomy has played a critical role in the care of infants since the early 1900s. Prior to the 1800s, tracheostomies were viewed with skepticism and criticism because these procedures were performed for acute airway obstruction and associated with high mortality rates. The relative success of tracheostomy in the treatment of children with diphtheria helped increase acceptance of the procedure. Holinger published a 30-year review of infant tracheostomy in 1965, demonstrating more acceptance of the procedure, improved technology of tracheostomy tubes, and an increasing list of indications, primarily for airway obstruction. Unfortunately, the mortality changed very little during that time period, with mortality rates approximately 30% for these infants.

The mid 1900s heralded great advances in neonatal resuscitation and ventilation. In 1953 Donald and Lord published a description of an infant mechanical ventilation device. ^, In 1965, McDonald and Stocks demonstrated success in longer-term intubation and ventilation in neonates. ^, Continuous positive pressure ventilation for respiratory distress of newborns was published in 1971. The 1960s also saw the establishment of the first neonatal intensive care units, and more infants were surviving conditions that in decades past were considered fatal.

The history of neonatal tracheostomy has been an evolving story of changing indications, technological advancements, and improvements in survival.

An understanding of the history of neonatal tracheostomy and neonatal care provides insight into the current evidence-based management of neonatal tracheostomy and the challenges now faced. The landscape of neonatal tracheostomy is changing. Very low birth weight preterm infants are now surviving, and noninvasive methods of respiratory support for these infants are reducing morbidity. Young children with severe chronic cardiopulmonary or neurologic disorders are managed with ventilators both in the neonatal intensive care unit (NICU) and out of the hospital. Some of the questions we now face for neonatal tracheostomy center on appropriate timing for tracheostomy, improving postoperative care pathways, decreasing morbidity of the procedure and subsequent care, facilitating adaptive neurodevelopment and communication, and improving quality of life after tracheostomy.

Pathophysiology

Multiple factors impact the pathophysiology and indications of neonatal tracheostomy. Unique neonatal anatomy, physiology, and medical conditions associated with prematurity influence tracheostomy decisions in the neonatal period.

The infant and neonatal airway diameter and length will vary by gestational age. The narrowest portion of the infant airway is at the glottis and subglottis, and these locations are the most common sites of postintubation stenosis. For a newborn, the subglottis has a 3.5- to 4-mm inner diameter. The tracheal length from glottis to carina is about 40 mm. Premature infants may have a subglottic airway of less than 3 mm. Airflow and effective ventilation in these small airways are influenced by Bernoulli’s and Poiseuille’s equations. Small changes in airway size will have significant effects on airway pressure, dynamic collapse, and resistance to flow. The clinical implication for many preterm infants is that airway edema or stenosis changes at the 1-mm level or less can destabilize effective ventilation, requiring increased support or tracheostomy. Subglottic stenosis occurred in 12% to 20% of infants with prolonged intubation in the 1960s. With contemporary neonatal respiratory care, rates of stenosis are typically around 1%. ^, Tracheostomy can be used to bypass levels of stenosis or decrease the need for respiratory support by removing upper airway resistance.

Typical indications for neonatal tracheostomy are prolonged ventilation, facilitation of ventilator weaning, upper airway obstruction, subglottic stenosis, or infectious etiologies. Although Holinger demonstrated infectious etiologies and airway obstruction as the most common indication for neonates in the 1960s, chronic cardiopulmonary and neurologic disorders are now the primary indications for tracheostomy. Multiple studies have described this shift from infectious indications for tracheostomy to cardiopulmonary and neurologic indications in neonates who have comorbid conditions. ^{, , , , ,}

Clinical Features and Indications

When tracheostomy is required, the decisions of timing and patient selection are critical to reduce morbidity. However, a limiting factor is the size of the neonatal airway in relation to the smallest available tracheostomy tube outer diameter (OD). The inner diameter of a full-term neonatal trachea is approximately 3.5 to 4 mm. Extremely premature infants may have an inner diameter of 2 mm or smaller. Currently the smallest OD tracheostomy tube is the 2.5 Tracoe with an OD of 3.6 mm or a 2.5 NEO Bivona TTS cuffed trach with an OD of 4.0 mm. Tracheal length also may be a factor in being able to accommodate the 30 mm of length of the tracheostomy tubes. These anatomic constraints are critical when considering airway interventions prenatally. Since the 1990s, ex utero intrapartum treatment procedures created the possibility of prenatal airway management for cases of congenital high airway obstruction (CHAOS), airway tumors, laryngeal and tracheal stenosis, and lymphatic malformations.

In addition to tracheal size and gestational age, patient weight is a consideration. Studies of other procedures have shown increased morbidity and mortality in procedures performed in neonates weighing less than 2.5 kg.

There is no established weight requirement for a tracheostomy procedure. Tracheostomy performed in infants with weights between 2.0 and 2.5 kg is common. Rawal et al. did not find increased morbidity when comparing infants <2.5 kg and >2.5 kg in an American College of Surgeons National Surgical Quality Improvement Program–Pediatric (ACS NSQIP-P) Database study. The data regarding appropriate timing of tracheostomy in infants is based on retrospective studies. It appears that the timing of tracheostomy does not decrease the duration of mechanical ventilation in the majority of infants.

Advances in noninvasive ventilation of newborns have improved morbidity and mortality through decreasing intubations and related iatrogenic lung and laryngotracheal injury. Systematic reviews have demonstrated the efficacy and safety of these methods compared with traditional orotracheal intubation. The implications of these advances for neonates requiring tracheostomy are varied. The total number of infants requiring tracheostomy may be decreasing, along with the aforementioned decrease in subglottic stenosis rates. ^, However, tracheostomy rates may be increasing in certain subpopulations of very low birth weight premature infants with more severe cardiopulmonary disease. ^, In some of these critical ill neonates, the risk of tracheostomy may be unacceptable. Highly unstable pulmonary hypertension or cardiopulmonary disease can be relative contraindications. If the neonate is unable to be transported safely to the operating room, be manipulated and positioned for surgery, and tolerate exchange of the endotracheal tube to a tracheostomy tube, then surgery should be delayed or deferred. Table 66.1 lists common indications and relative contraindications for neonatal tracheostomy.