Anesthesia for Preterm Infants

Anesthesia providers often care for patients with severe preexisting health conditions. These patients fall across all age ranges, from neonates¹ to older adults.² In some cases, anesthesiology practitioners must provide medications to children who were born prematurely, either immediately after birth or months later.³ In order to prepare themselves to care for preterm neonates or ex-preterm infants, anesthesia providers should understand the health consequences of premature birth and anesthesia recommendations for these populations. 

A premature birth is a birth that takes place more than three weeks before the baby’s estimated due date; in other words, prematurity occurs before 37 weeks of gestation.⁴ Complications associated with prematurity vary, often depending on how early the baby was born.⁴ Late preterm babies are born between 34 and 36 completed weeks of pregnancy, moderately preterm between 32 and 34 weeks, very preterm less than 32 weeks and extremely preterm at or before 25 weeks.⁴ Though the mortality rate for preterm infants has improved over the last four to five decades, infants born before term remain vulnerable to various complications.⁵ A premature baby has not had adequate time for body systems development; thus, the baby may have or develop respiratory distress syndrome, chronic lung disease, intestinal injury, immunocompromise, cardiovascular disorders, hearing and vision problems and neurological issues.⁵ Extremely preterm infants are at risk for intraventricular hemorrhage, which is brain bleeding that can lead to long-term neurological impairment and decreased survival; necrotizing enterocolitis (NEC), in which the intestinal wall becomes infected, inflamed and potentially destroyed; retinopathy of prematurity (ROP), which entails abnormal development of retinal blood vessels that can lead to blindness; and bronchopulmonary dysplasia, which is a chronic lung disease caused by damage from mechanical ventilation and long-term oxygen use.⁶ Though preterm newborns at 23 weeks can have a survival rate of up to 65 percent, each week in utero after week 23 increases survival rates by six to nine percent.⁶ Preterm infants face higher risk for various health conditions than full-term infants, and may continue to have health issues into adulthood.⁶ 

Because of the mortality and acute complications associated with preterm birth, anesthesia providers must be particularly cautious when providing care to preterm infants.⁵ Caring for a preterm neonate is an anesthetic challenge due to the infant’s size, incomplete organ development and immature physiological function.³ Due to high risk of complications, anesthesia providers must carefully select the type of anesthesia. For example, Gurria et al. found that regional anesthesia was preferable to general endotracheal anesthesia for inguinal hernia repair in very preterm neonates.⁷ Beyond providing anesthesia for preterm infants, clinicians may need to anesthetize infants who were preterm but have spent several months out of the womb.⁸ Many preterm babies survive the neonatal intensive care unit (NICU) and subsequently present to the operating room for surgical procedures.⁸ These babies, who have now reached more than 37 weeks since conception, are known as ex-preterm infants.⁸ Caring for ex-preterm infants is different from caring for full-term infants, regardless of their post-birth age. Havidich et al.’s prospective cohort study found that patients born preterm were nearly twice as likely to develop sedation- or anesthesia-related adverse events, and this risk continued up to 23 years of age.⁹ While Rozema et al.’s chart review showed that no infants—whether preterm, ex-preterm or term—had apnea after deep sedation, their study had a small sample size and retrospective design.¹⁰ Because of the potential for pulmonary damage in ex-preterm infants, some researchers have explored alternatives to general anesthesia in this population. Waurick et al. found that caudal anesthesia combined with dexmedetomidine sedation was effective for lower abdominal and extremity surgery in ex-preterm and full-term infants with severe comorbidities.¹¹ Meanwhile, Hussein and Mostafa found that spinal anesthesia without sedation was safe and effective for lower abdominal operations in ex-preterm neonates.¹² Overall, multiple sources of data suggest that local anesthesia may be preferable to general anesthesia in preterm and ex-preterm infants due to risk of ventilation-related damage and apnea.¹³ 

Anesthesia for the preterm or ex-preterm infant can be complex. Children who are born prematurely often have respiratory, intestinal, immunologic, cardiovascular, ocular, aural or neurologic difficulties that can extend into later life. In order to avoid complications, such as lung injury due to mechanical ventilation, anesthesia providers must take extra precautions when caring for preterm or ex-preterm infants. Future research is needed to explore the benefits of local versus general anesthesia in operations on preterm infants. 

1. Shi Y, Hu D, Rodgers EL, et al. Epidemiology of general anesthesia prior to age 3 in a population-based birth cohort. Paediatric Anaesthesia. 2018;28(6):513–519. 

2. Kanonidou Z, Karystianou G. Anesthesia for the elderly. Hippokratia. 2007;11(4):175–177. 

3. Reddy A, Bowe EA. Anesthesia Considerations in a Premie. In: Goudra BG, Duggan M, Chidambaran V, et al., eds. Anesthesiology: A Practical Approach. Cham: Springer International Publishing; 2018:463–471. 

4. Mayo Clinic. Premature birth: Symptoms & causes. Diseases & Conditions December 21, 2017; https://www.mayoclinic.org/diseases-conditions/premature-birth/symptoms-causes/syc-20376730. 

5. Institute of Medicine (US) Committee on Understanding Premature Birth and Assuring Healthy Outcomes. Mortality and Acute Complications in Preterm Infants. In: Behrman R, Butler A, eds. Preterm Birth: Causes, Consequences, and Prevention. Washington, DC: National Academies Press (US); 2007. 

6. Ward RM, Beachy JC. Neonatal complications following preterm birth. BJOG: An International Journal of Obstetrics & Gynaecology. 2003;110(s20):8–16. 

7. Gurria J, Kuo P, Kao A, Christensen L, Holterman A. General endotracheal vs. non-endotracheal regional anesthesia for elective inguinal hernia surgery in very preterm neonates: A single institution experience. Journal of Pediatric Surgery. 2017;52(1):56–59. 

8. Badgwell JM. Anesthesia for the Ex-Premature Infant. In: Stanley TH, Schafer PG, eds. Pediatric and Obstetrical Anesthesia: Papers presented at the 40th Annual Postgraduate Course in Anesthesiology, February 1995. Dordrecht: Springer Netherlands; 1995:229–243. 

9. Havidich JE, Beach M, Dierdorf SF, Onega T, Suresh G, Cravero JP. Preterm Versus Term Children: Analysis of Sedation/Anesthesia Adverse Events and Longitudin