The aim of this study is to increase the detection of undiagnosed obstructive sleep apnea (OSA) and secondly to increase the sensitivity for detection of respiratory depression (< 6 breaths per minute) in post operative patients on the general care nursing unit.

Measures: This is an IRB approved prospective trial beginning with randomization in the post anesthesia care unit (PACU) and continuing for thirty six hours post orthopedic surgical procedure. The patients are randomized into a capnography or standard of care group and the percentage of newly identified OSA patients were measured in each group using the criteria set forth by 2006 American Society of Anesthesiologist practice guideline (Anesthesiology 2006; 104:1081-93).

Background/Changes: Hospital complications are three times higher in patients with obstructive sleep apnea and the majority of these complications are related to opioid induced respiratory depression (Mayo Clin Proc Sept 2001:897-905). American Society of Anesthesiologist 2006 practice guideline for perioperative management of patients with obstructive sleep apnea (Anesthesiology 2006; 104:1081-93) lists the criteria for identifying undiagnosed obstructive sleep apnea. One of the risk factors in the guideline lists apnea (pauses in breathing). Capnography measures apnea episodes and continuously monitors respiration rate.

As previously described, five percent of the general population has obstructive sleep apnea (OSA) and the prevalence among patients requiring surgery is 9% (NEJM 1993; 328:1230-1235). Between 50-80% of OSA individuals are undiagnosed when presenting for surgery.

Inclusion Criteria:

• Orthopedic surgical procedure

• Respiration rate < 10 breaths per minute requiring supplement oxygen

• One of the following:

  • body mass index >30
  • history of snoring
  • basal rate of opioid, and
  • one event of RR <10 in the post anesthesia care unit.

Exclusion Criteria:

• COPD
• < 18 y/o
• A diagnosis of obstructive sleep apnea.