A nocturnal oximeter is used as a diagnostic tool for breathing disorders of sleep, such as Obstructive Sleep Apnea or Nocturnal Hypoventilation. A small monitor is attached to your finger and worn overnight during your hours of sleep. It records your oxygen saturation levels and pulse rates throughout the night while you are asleep. In the morning, you simply turn it off and return it to Livingston HealthCare Cardiopulmonary Services. Upon its return to the department, a report of your study is generated and given to your provider for interpretation.