The change of airway responsiveness and alveolar macrophage (AM) immunity occurs during the pathogenesis of asthma. Macrophage-associated airway protection in patients with asthma is affected positively or negatively by propofol general anesthesia. The investigators hypothesized that the effects of propofol on asthmatic AMs and corresponding airway reactivity in vivo is different from the in vitro research. Through in vivo airway hyperresponsiveness (AHR) observation and clinical investigation of AM immune functions from asthma patients undergoing propofol general anesthesia to clarify the precise effects of propofol on AM immunity, and to provide theoretical basis for the clinical administration of propofol in asthmatic patients. This would optimize the practice of clinical anesthesia, especially for those with the tendency of AHR.

Inclusion Criteria:

• ASA physical status I-II;
• Aged from 18 years to 45 years;
• Patients with or without asthma or a history record of asthma;
• Undergoing elective lumpectomy under general anesthesia.

Exclusion Criteria:

• Allergy to propofol and opioids, a history of the use of centrally-acting drugs of any sort, chronic pain and psychiatric diseases records;
• Participants younger than 18yr，older than 45yr or pregnancy;
• Those who were not willing to or could not finish the whole study at any time;
• The PACU assessing score was under 6 on a scale of 10 (measuring somnolence, respiration, movement, color, and blood pressure on 0-2 scales), and arterial oxygen saturation measured by pulse oximetry (SaO2) was 92% or lower (supplemental oxygen was permitted).

Patients with or without asthma undergoing general anesthesia