Risk Factors of Klein et al for Apnea After Immunizing a Patient in the Neonatal Intensive Care Unit

 

Apnea was defined as a cessation of respiration for >= 20 seconds.

 

The most important risk factor for predicting apnea following an immunization was a history of apnea in the NICU. This was associated with an adjusted odds ratio of 26. The presence of 2 or more apneic episodes during the 24 hours prior to vaccine admininstration was associated with a higher risk.

 

Other risk factors for an apneic episode:

(1) SNAP II score > 10

(2) body weight at immunization < 2,000 grams

(3) age < 67 days

 

Almost all affected infants were born prematurely with a gestational age < 31 weeks.

 

Most post-vaccination apneic episodes occur within the 48 hours after vaccination. However, of 49 infants without preimmunization apnea and with at least 1 risk factor who were discharged within 48 hours after an immunization, 2 (4%) were readmitted for apnea.