Table 1 Patients and baseline characteristics
|  | LMA (n = 48) | HFNC (n = 48) | P-value |
|---|---|---|---|
Age, y | 72.0(3.6) | 73.0(4.0) | 0.192 |
BMI, kg/m2 | 24.4(2.8) | 23.8(2.3) | 0.234 |
ASA status    I    II    III | 2(4.2%) 42(87.5%) 4(8.3%) | 1(2.1%) 41(85.4%) 6(12.5%) | 0.803 |
Sex    male    female | 29(60.4%) 19(39.6%) | 29(60.4%) 19(39.6%) | > 0.99 |
Smoking | 16(33.3%) | 15(31.3%) | 0.827 |
Breath-holding test    < 30s    ≥ 30s | 5(10.4%) 43(89.6%) | 8(16.7%) 40(83.3%) | 0.371 |
Pulmonary function, L    FVC    FEV1 | 3.11[2.7–3.4] 0.67[0.6–0.7] | 3.06[2.7–3.3] 0.67[0.6–0.7] | 0.965 0.437 |
Cardiovascular comorbidity    Hypertension    CHF    Arrhythmia | 20(41.7%) 0 8(16.7%) | 18(37.5%) 0 10(20.8%) | 0.676 - 0.601 |
Hemoglobin, g/dL | 13.68(1.3) | 13.81(1.4) | 0.628 |
Stone location    Proximal    Mid    Distal | 3(6.3%) 9(18.8%) 36(75%) | 5(10.4%) 8(16.7%) 35(72.9%) | 0.883 |
   Stone size    ≤ 10 mm    > 10 mm | 40(83.3%) 8(16.7%) | 42(87.5%) 6(12.5%) | 0.563 |
Preoperative QOR-15 score Preoperative pH Preoperative PaO2, mmHg Preoperative P/ F, mmHg Preoperative PaCO2, mmHg Preoperative RR Preoperative Airway dryness score    Mouth    Throat | 140.5[138.25-143.75] 7.39[7.36–7.42] 76.73(4.84) 365.38(22.93) 39[36–42] 16[15–16] 4[4–5] 4[4-4.8] | 141.0[135.25–144.0] 7.36[7.35–7.41] 76.10(5.58) 362.40(26.58) 36[35–41] 16[16–16] 4[4–4] 4[4–4] | 0.869 0.125 0.367 0.367 0.097 0.388 0.054 0.218 |