Table 2 Primary and secondary endpoints
The NHF group N = 37 | The LFO group N = 38 | Association measure | Estimate (95% CI) | p value | |
|---|---|---|---|---|---|
Incident of marked hypercapnia (the proportion of patients experiencing a PtCO2 ≥ 60 mmHg) | 2.7% (1/37) | 18.4% (7/38) | Risk ratioa | 0.15 (0.02 to 1.13) | 0.066 |
Risk difference (%)b | -15.7 (-29.1 to -2.4) | 0.021 | |||
Time-weighted average for PtcCO2 (mmHg/min)c | 47.2 ± 4.6 | 48.2 ± 5.7 | Mean difference | -0.97 (-3.35 to 1.41) | 0.421 |
Duration of hypercapnia (min)d (PtCO2 ≥ 50 mmHg) | 7 (0 to 99) | 14.5 (0 to 206) | 0.313 | ||
Incident of hypoxia (SpO2 ≦ 90%) (the proportion of patients experiencing an SpO2 ≦ 90%) | 8.1% (3/37) | 5.3% (2/38) | Risk ratioe | 1.54 (0.27 to 8.70) | 0.62 |
Risk difference (%)f | 2.8 (-8.5 to 14.2) | 0.62 | |||
Hypercapnia (PtCO2 ≥ 50 mmHg) | 56.8% (21 /37) | 63.2% (24/38) | Risk ratioa | 0.91 (0.63 to 1.31) | 0.605 |
Risk difference (%)b | -7.5 (-29.0 to 14.0) | 0.495 | |||
Ramsay score at start of procedureg | 5 (4 to 6) | 5 (4 to 6) | 0.488 | ||
Initial dose of pethidine hydrochloride (mg) | 35 (0 to 35) | 35 (0 to 35) | Relative Riskh | 0.99 (0.91 to 1.07) | 0.761 |
Initial dose of midazolam (mg) | 3 (2 to 5) | 3 (2 to 6) | Relative Riskh | 0.99 (0.77 to 1.26) | 0.904 |
Total dose of pethidine hydrochloride (mg) | 35 (0 to 105) | 70 (0 to 175) | Rate ratioi | 0.96 (0.91 to 1.02) | 0.177 |
Total dose of midazolam (mg) | 6.0 (2 to 20) | 7.5 (3 to 35) | Rate ratioi | 1.00 (0.85 to 1.17) | 0.967 |