T&A Triage with or without Preoperative Polysomnography Clinical Pathway – Inpatient and Outpatient Specialty Care

Review Polysomnography Results

  • Polysomnography is a test to diagnose sleep disorders.
  • It records brain waves, oxygen level in the blood, heart rate, breathing, and eye and
    leg movements.
  • When interpreting results the Apnea/Hypopnea Index (AHI) and oxygen desaturation levels
    are used to indicate the severity of obstructive sleep apnea.

Interpreting Polysomnography Results

Apnea/Hypopnea Index (AHI)

Number of events per hour, calculated as:

Apneas
No airflow for 10 secs or longer
+ Hypopneas
Shallow breathing where airflow reduced by
at least 50%, lasting 10 secs or longer

Normal AHI is < 1.5/hr

Gas Exchange

Preoperative SpO2 nadir < 80% or peak CO2 > 60 mmHg are more consistent predictors of postoperative respiratory complications than apnea-hypopnea indices.

Oxygen nadir is the lowest oxygen saturation a patient drops to [normal oxygen nadir (SpO2) > 92].

CO2 peak < 55 mmHg or > 50 mmHg for no more than 25% total sleep time (the latter is a better measure as CO2 can peak after a single sigh)

Apnea hypopnea index

arterial oxygen saturation values

 

carbon dioxide values

Graphs show the percentage of patients with respiratory complications at:

  • Each level of apnea hypopnea index
  • Arterial oxygen saturation nadir
  • Peak end-tidal CO2

 

Reference

Predictors of Perioperative Complications in Higher Risk Children after Adenotonsillectomy for Obstructive Sleep Apnea: A Prospective Study