Risk Factors for Overnight Desaturation Following Sedation for Non-Invasive Radiology Studies in Children with Sleep Apnea

Background: Children with sleep apnea are at increased risk for adverse respiratory events following surgical procedures involving the airway such as tonsillectomy. Risk following sedation for non-invasive procedures is unclear. The objective of this study was to identify risk factors for overnight desaturation events (ODE) in patients with sleep apnea admitted after sedated magnetic resonance imaging (MRI).

Methods: 1407 hospitalizations for children with a diagnosis of sleep apnea (by ICD-9 code) occurred at Children’s Hospital Los Angeles (CHLA) from 5/1/2011 to 2/1/2015.  128 (9%) encounters were solely for observation after MRI representing 97 unique patients.  The first post-MRI admission for each patient during the study period underwent chart review.  ODE was defined as sustained oxygen saturation <90% with need for increased oxygen or adjustment of respiratory support after release from recovery. Characteristics of patients with ODEs were compared to those without by chi-squared analysis or Mann-Whitney U.  Logistic regression was used to identify associations with ODE.  

Results: 9/97 (9.3%) patients had ODEs.  The average time from end of sedation to ODE was 10.25 hours. Length of stay for patients with ODE was longer (median 2 vs. 1 day, p<0.001).  Overall patients were 56% male, 58% Hispanic, with a median age of 4.9 years [IQR 1.88 – 9.98] and median body mass index (BMI) of 17.9 [IQR 15.21 – 24.55].   Patients with and without ODE were similar in terms of race, gender, duration of sedation, BMI, and sleep apnea type (central, obstructive, or clinically suspect).  On logistic regression, increasing age (OR 1.12, p=0.047), apnea-hypopnea index (AHI; OR 1.07, p=0.007) on sleep study, and use of home positive pressure ventilation (BPAP or CPAP; OR 4.86, p=0.028) were all associated with ODE.  

Conclusions: 90% of children with sleep apnea admitted for overnight observation following sedated MRI did not have an ODE.  Age, AHI, and use of home positive pressure ventilation were identified as associations with ODE that could potentially be used to target higher-risk patients and avoid unnecessary hospitalizations.