https://www.infirmiere-canadienne.com/blogs/ic-contenu/2024/11/18/humidificateur-bulles-froides-doxygene
Evidence shows bubbling oxygen through water does not meet physiological demands or alleviate symptoms of dryness — and may increase infection risk
By Woochan Park
November 18, 2024
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Although traditional practices such as cold-water humidification have been widely used, evidence suggests that they are insufficient and potentially harmful
Using a cold-water humidifier to bubble oxygen has long been a routine practice in nursing. In Canadian Fundamentals of Nursing, sixth edition (2019, p. 979), Astle, Duggleby, and Potter (2019) state that “[h]umidification is necessary for patients receiving oxygen therapy at >4L/minute. Bubbling oxygen through water can add humidity to the oxygen delivered to the upper airways, as with a nasal cannula or face mask.”
However, this practice warrants reconsideration. Substantial evidence indicates that bubbling oxygen with a cold-water humidifier is inadequate for meeting physiological demands, does not significantly alleviate symptoms of dryness experienced by patients, and may increase the risk of infection.
Inadequate humidification
Oxygen bubbled through water without a heat source results in insufficient humidification to meet physiological needs. Davis, Parbrook, and Kenny (1995, pp. 156–157) assert that the humidification levels achieved through this method fall short of what is required to prevent dryness and irritation of the mucosal membranes. Santana et al. (2021) further support this, noting that cold bubble humidification of low-flow oxygen does not prevent acute changes in inflammation and oxidative stress in the nasal mucosa. This insufficiency can lead to discomfort and potential complications for patients requiring long-term oxygen therapy.
Lack of symptom relief
The efficacy of cold-water humidification in alleviating symptoms of dryness is also questionable. Wen et al. (2017) found no significant differences in symptoms such as dry nose, dry throat, nosebleeds, chest discomfort, the smell of oxygen, and changes in SpO2 levels between patients receiving bubbled oxygen and those who did not. This lack of statistical significance suggests that the practice does not provide the expected relief from dryness and related symptoms, calling into question its clinical benefit.
Risk of infection
Another critical concern is the potential for contamination of the water source used in humidifiers (Wen et al., 2017). Contaminated water can introduce pathogens into the respiratory system, increasing the risk of infections. This is particularly concerning for patients with compromised immune systems or those already vulnerable due to their underlying conditions.
Recommendations
Given the limitations and potential risks associated with cold-water humidification, alternative methods should be considered.
- The British Thoracic Society recommends normal saline nebulization to counteract the effects of dryness during low-flow oxygen administration (O’Driscoll, Howard, Earis, & Mak, 2017). Saline nebulization can effectively provide the necessary moisture without the contamination risks associated with cold-water humidifiers.
- Additionally, nursing interventions such as encouraging fluid intake and using hydrophilic moisturizers can help reduce discomfort related to dryness. Ensuring that patients stay hydrated and applying moisturizers can significantly enhance their comfort and overall experience during oxygen therapy.
In conclusion, although traditional practices such as cold-water humidification have been widely used, evidence suggests that they are insufficient and potentially harmful. Despite the happy bubbly sound it offers, we as health-care professionals should adopt a practice that reflects the current best evidence.
References
Astle, B. J., Duggleby, W., & Potter, P. A. (Eds.). (2019). Canadian fundamentals of nursing (6th ed.). Elsevier Canada.
Davis, P. D., Parbrook, G. D., & Kenny, G. N. C. (1995). Basic physics and measurement in anesthesia (4th ed.). Butterworth-Heinemann.
O’Driscoll, B. R., Howard, L. S., Earis, J., & Mak, V. (2017). British Thoracic Society Guideline for oxygen use in adults in healthcare and emergency settings. BMJ Open Respiratory Research, 4(1), e000170. doi:10.1136/bmjresp-2016-000170
Santana, L. A., Bezerra, S. K. M., Saraiva-Romanholo, B. M., Yamaguti, W. P., de Fátima Lopes Calvo Tibério, I., … & Righetti, R. F. (2021). Cold bubble humidification of low-flow oxygen does not prevent acute changes in inflammation and oxidative stress in nasal mucosa. Scientific Reports, 11(1), 14352. doi:10.1038/s41598-021-93837-x
Wen, Z., Wang, W., Zhang, H., Wu, C., Ding, J., & Shen, M. (2017). Is humidified better than non‐humidified low‐flow oxygen therapy? A systematic review and meta‐analysis. Journal of Advanced Nursing, 73(11), 2522–2533. doi:10.1111/jan.13323
Woochan Park is a nursing student at Camosun College and the University of Victoria’s BSN program.
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