An apparatus comprises a flow sensor configured to sense airflow between a respiration machine and a patient, a first connector configured to communicate air between the flow sensor and the patient, a second connector configured to communicate air between the flow sensor and the respiration machine, multiple pressure sensing ports configured for connection to pressure sensing tubes and configured to communicate gas pressure between the flow sensor and a pressure flowmeter, and a filter integrated with the flow sensor between the first connector and the pressure sensing ports and configured to communicate gas pressure therethrough while preventing contaminants from passing from the flow sensor to the pressure sensing tubes.