4. Do the Intersurgical products meet the AARC guidelines? All Intersurgical filter/HME combinations and heat and moisture exchangers are designed to return approximately 30 mg H2O at 500 ml Vt to meet the AARC recommendations. Different product designs result in moisture returns between 29.1 mg H2O and 32.8 mg H2O when tested according to ISO 9360.6. All test protocols are available through the Intersurgical customer service department.