Combining Combivent Nebulization with Distilled Water
Yes, Combivent nebulization should be combined with distilled water (or sterile normal saline) to achieve the proper volume for effective nebulization, typically bringing the total volume to 2.0-4.5 ml in the nebulizer chamber. 1
Standard Nebulization Practice
The volume of fluid in the nebulizer chamber is typically 2.0-4.5 ml for optimal drug delivery. 1 Since Combivent solution comes in a smaller volume (typically 3 ml unit-dose vials), adding distilled water or sterile normal saline to reach the appropriate volume is standard practice when using nebulizer systems that require larger volumes. 1
Bronchodilators such as β agonists and ipratropium bromide (the components of Combivent) are water-soluble drugs that behave like saline and can be diluted appropriately for nebulization. 1
Technical Requirements for Effective Delivery
- A gas flow rate of 6-8 l/min is required to nebulize 50% of the particles to 2-5 µm diameter for optimal deposition into the small airways. 1
- Most hospital nebulizers leave 0.5 ml of fluid as residual after nebulization, so starting with 2-2.5 ml of drug fluid is sufficient. 1
- For bronchodilators, 10 minutes should be sufficient for complete nebulization. 1
Driving Gas Selection (Critical Safety Point)
For COPD patients, the nebulizer should be driven by compressed air, NOT oxygen, due to the risk of carbon dioxide retention. 1 This is a critical safety consideration that takes precedence over the diluent question.
- In acute severe asthma, oxygen should be used to drive the nebulizer as patients are hypoxic. 1
- In COPD and all other lung diseases, air should be used unless oxygen is specifically prescribed. 1
- Some patients can receive low-flow oxygen via nasal cannulae while nebulizing drugs with air. 1
Cleaning and Maintenance
The nebulizer should be emptied after each use and washed at least once daily in warm water to avoid crystallization and growth of micro-organisms in residual fluid. 1 The patient should have their own tubing, nebulizer, and mouthpiece/mask. 1