An efficiency comparison of four heat and moisture exchangers used in the laryngectomized patient.

Bypassing the upper airway places the burden of humidification on the lower airway. For this reason passive heat and moisture exchangers (HMEs) are used in the laryngectomized patient in an attempt to minimize the effect of lost upper airway function. We measured efficiency and airflow resistance and calculated the costs of four HMEs used in the laryngectomized patient. The HMEs were measured according a modified International Standards Organization (ISO) 9360 standard. The airflow resistance was measured at flow rates of 15, 30, and 60 L/min. The measurements were repeated three times. Costs were calculated with two realistic scenarios. The study found that there are significant differences in moisture output and airflow resistance between the HMEs tested. There are major daily cost differences between these devices. This study shows that filter material and size influence the HME's moisture output efficiency and airflow resistance considerably. The construction differences and filter and housing type have great influence on the HME's daily costs. We believe that knowledge of the efficiency in combination with the average daily costs of the HMEs allows the clinician to make a balanced choice of which filter to use.