Mitchell Jolyon P, Nagel Mark W
Director of Scientific Affairs, Trudell Medical International, London, Canada.
Prim Care Respir J. 2007 Aug;16(4):207-14. doi: 10.3132/pcrj.2007.00034.
Valved holding chambers (VHCs) are prescribed with pressurised metered dose inhalers (pMDIs) to improve medication delivery for the treatment of respiratory diseases because they reduce the need for the patient to co-ordinate inhaler actuation with the onset of inhalation. Although mechanically robust and clinically effective if properly designed and pre-conditioned, there are several causes of inconsistent medication delivery if this is not the case. These include: electrostatic charge; incorrect operation of inhalation and exhalation valves; and the fit of the facemask - where present - to the face. In addition, behavioral factors, such as not following patient instructions for use and maintenance, and imperfect breathing technique, amplify overall variability. Aids such as valve movement indicators that provide patient feedback are helpful in order to minimise these factors.
This article reviews recent literature concerning the causes of inconsistent drug delivery and the improvements that have been made by manufacturers to VHC devices, and assesses the clinical implications. The attributes of a well-designed VHC are summarised.
带储雾罐的定量吸入器（VHC）与压力定量吸入器（pMDI）配合使用，以改善呼吸道疾病治疗中的药物递送，因为它们减少了患者在吸气开始时协调吸入器启动的需求。尽管如果设计合理并经过预处理，其机械性能坚固且临床效果良好，但如果情况并非如此，则存在多种导致药物递送不一致的原因。这些原因包括：静电电荷；吸入和呼气阀操作不当；以及面罩（若有）与面部的贴合度。此外，行为因素，如不遵循患者使用和维护说明以及不完善的呼吸技术，会放大总体变异性。诸如提供患者反馈的阀门运动指示器等辅助工具有助于最小化这些因素。
本文回顾了有关药物递送不一致原因的近期文献以及制造商对VHC装置所做的改进，并评估了临床意义。总结了设计良好的VHC的特性。
