This study will compare the data from pulse oximeters to capnographers as they are used to monitor patients who are being observed in the Emergency Department for a suspected overdose of alcohol or other drugs. The investigators will compare monitor data from patients who are and are not on supplemental oxygen, the ability of the monitors to predict the occurrence of airway interventions, and to detect ventilator changes noted on the opposing monitor. There will not be any interventions during this study other than the collection of data from the monitors and observation of the care of patients.

Inclusion Criteria:

• Airway is being monitored as a result of overdose

Exclusion Criteria:

• Under 18 years old
• Unable to give informed consent at baseline
• Prisoners

Patients presenting to the emergency department at an urban county hospital.