Comparison of generated nasopharyngeal end-expiratory pressure (pEEP) and nasopharyngeal end-expiratory carbon dioxide concentration (pEECO2) in each weight group and flow rate
| pEEP | pEECO2 | ||||
| HFNC flow rate (L/min) | Weight category (g) | Mean±SD | P value* | Mean±SD | P value† |
| 2 | <1000 | 3.0±1.6 | 0.021 | 1.6±1.3 | 0.014 |
| 1000–1500 | 2.3±1.2 | 2.2±1.7 | |||
| >1500 | 1.8±0.7 | 3.2±1.5 | |||
| 3 | <1000 | 4.2±1.9 | 0.005 | 1.10±0.99 | 0.003 |
| 1000–1500 | 3.2±1.5 | 1.73±1.54 | |||
| >1500 | 2.6±0.6 | 2.96±1.41 | |||
| 4 | <1000 | 5.0±1.9 | 0.005 | 0.6±0.6 | 0.001 |
| 1000–1500 | 3.6±1.3 | 2.0±1.6 | |||
| >1500 | 3.4±0.9 | 2.5±1.4 | |||
| 5 | <1000 | 4.6±1.5 | NS | 0.7±0.7 | 0.002 |
| 1000–1500 | 4.0±1.2 | 2.0±2.1 | |||
| >1500 | 3.9±1.6 | 2.5±1.6 | |||
| 6 | <1000 | 5.5±2.2 | NS | 0.5±0.8 | <0.0001 |
| 1000–1500 | 4.4±1.2 | 1.3±1.5 | |||
| >1500 | 4.5±1.3 | 2.2±1.5 | |||
| 7 | <1000 | 5.9±2.5 | NS | 0.2±0.3 | <0.0001 |
| 1000–1500 | 5.1±1.4 | 1.1±1.6 | |||
| >1500 | 5.1±1.8 | 1.9±1.5 | |||
| 8 | <1000 | 6.6±2.5 | NS | 0.2±0.4 | <0.0001 |
| 1000–1500 | 6.0±2.0 | 1.2±2.1 | |||
| >1500 | 5.8±1.8 | 1.8±1.5 | |||
Infants weighing <1000 g n=15, 1000–1500 g n=15, >1500 g n=14.
Expressed in means±SD.
*Jonckheere-Terpstra test for ordered alternatives showed that there was a statistically significant trend of higher pEEP in infants weighing <1000 g compared with infants 1000–1500 g and/or >1500 g at flows 2–4 L/min.
†Jonckheere-Terpstra test for ordered alternatives showed that there was a statistically significant trend of lower pEECO2 in infants weighing <1000 g compared with larger weight groups infants 1000–1500 g and/or >1500 g across all flows.
NS, non-significant.