Shupak
Humidification of hyperbaric oxygen produced improvement in pulmonary flow after one treatment but this benefit was not sustained over further treatments.
Clinical Bottom Line: 1. Some improvement in pulmonary flow characteristics with humidification of hyperbaric oxygen after the first treatment, but these improvements are not sustained after subsequent treatments. 2. Some improvement in FEV1% and FEF25-75% with both dry and humidified oxygen after the first treatment. Appraised by: Mike Bennett, Dept. of Diving and Hyperbaric Medicine, Prince of Wales Hospital Sydney; Thursday, 8 April 1999
Clinical Scenario: A patient for routine hyperbaric therapy. Three-part Question: In patients receiving a course of hyperbaric oxygen therapy, does the humidification of the inspired oxygen compared to the administration of dry gases, result in any improvement (or less deterioration) in respiratory function? Search Terms: humidification, breathing circuits
The Study: Non-blinded concealed randomised controlled trial with intention-to-treat. Routine patients having hyperbaric oxygen therapy for the adjunctive treatment of chronic wounds in a multiplace chamber using a built in breathing apparatus. Control group (N =13;13 analysed): Hyperbaric oxygen therapy at 2.5ATA for 95 minutes daily for five days. Experimental group (N =13;13 analysed): As above but with oxygen on the inspiratory line passing through a bubble humidifier.
The Evidence:
| Non-Event Outcomes | Time to outcome | Dry group | Humidified group | P-value |
| Forced mid-expiratory flow rate after treatment (l/min) | Day one |
3.43 |
4.59 |
0.03 |
| % change in forced mid-expiratory flow rate after reatment, day 1 to day 5 (l/min) | Day five |
7.17 |
-2.87 |
>0.05 |
Comments: 1. Cross-over design, but return to baseline not clearly demonstrated. 2. Hyperbaric oxygen transiently improved pulmonary flow characteristics, more so if humidified. 3. This study suggests that there is little advantage in humidification of inspired oxygen during a course of hyperbaric therapy.
Expiry date: January 2022 References: 1. Shupak A, Abramovich A, Adir Y, Goldenberg I, Ramon Y, Halpern P, Ariel A. Effects on pulmonary function of daily exposure to dry or humidified hyperbaric oxygen. Respiratory Physiology 1997; 108:241-246.
