To be effective, spacers should have a volume of at least 110 mL and, as a result, are bulky ; many patients are therefore unwilling to carry these devices around. Patients must be reminded to shake the pMDI before use, something they tend to forget when the pMDI is left attached to the spacer device. Furthermore, patients should be warned against discharging more than one dose at a time of the pMDI into the spacer because this drastically reduces the total dose delivered per actuation . Certain spacers may have a strong electrostatic charge, especially if new . Washing a new spacer in mild dish soap may be necessary if previously effective doses are insufficient. The variety and quality of currently available volume spacers make the use of wet nebulization unnecessary in almost all patients, whatever their age or the severity of their condition. There have been several reports demonstrating conclusively that bronchodilator therapy in acute severe asthma can be delivered as effectively as, and more efficiently and at lower cost using pMDIs attached to a spacer device than with wet nebulization .