Objectives
Not all CPAP systems have similar performance characteristics [1]. We aimed to assess comfort levels using six different CPAP delivery systems.
Methods
Six healthy blinded volunteers subjectively ranked each system for ease of breathing and comfort. The CPAP systems were set to 5 cmH2O CPAP via standardised tubing, mouthpiece and nasal clips. Pressure, flow and volume at the mouthpiece were measured using an Datex AS3 monitor and logged to PC.
Results
The pressure fluctuations between inspiration and expiration at 25 l/min correlated well with the subjective ranking (P = 0.017), with differences most evident in the expiratory phase of the cycle (P = 0.04).
Conclusions
CPAP systems that minimise pressure fluctuations are more comfortable. Patient comfort can be improved by choosing and setting CPAP systems to minimise pressure fluctuations.
Table.
| Pressure deviation (cmH2O) from CPAP level at 25 l/min flow | ||||
|---|---|---|---|---|
| CPAP delivery system | Subjective ranking | Inspiration | Expiration | Overall |
| Respironics Vision | 1 | -0.8 | -0.1 | 0.6 |
| Respironics S/T | 2 | -0.6 | 0.1 | 0.8 |
| Drager Evita 4 (NIV) | 3 | -1.1 | 1.3 | 2.4 |
| Drager Evita 4 | 4 | -1.1 | 1.3 | 2.5 |
| Drager CF 800 | 5 | -1.3 | 0.7 | 2.0 |
| Siemens Servo 300 | 6 | -1.1 | 2.3 | 3.4 |
| Spearman Correlation with ranking P value | -0.76 | 0.83 | 0.89 | |
| 0.084 | 0.04 | 0.017 | ||
NIV, new non-invasive software.
References
- Austin PN. et al. Work of breathing characteristics of seven portable ventilators. Resuscitation. 2001;49:158–167. doi: 10.1016/S0300-9572(00)00358-0. [DOI] [PubMed] [Google Scholar]