What spirometry parameter would you recommend to assist a patient with asthma in monitoring her…

➤ When should I use a bronchodilator based on peak flow readings?
Follow your asthma action plan using PEF as percent of personal best. Green: >80% — continue routine therapy. Yellow: 50–80% — use a short‑acting bronchodilator and reassess; consider stepping up controller per plan. Red: <50% — use bronchodilator immediately and seek urgent medical care. Always correlate with symptoms.