General Medicine General b2becbac Hypopnea is defined as? A > 10% reduction in airflow for at least 10 seconds with > 1% desaturation on arousal B > 20% reduction in airflow for at least 10 seconds with > 2% desaturation on arousal C > 30% reduction in airflow for at least 10 seconds with > 3% desaturation on arousal D > 40% reduction in airflow for at least 10 seconds with > 4% desaturation on arousal