Baseline data and Hypoxic Challenge Testing results for those with no actual/potential R–L shunt versus those with an actual/potential R–L shunt or unrepaired/palliated
| Median (IQR) | No actual/potential R–L shunt | Actual/potential R–L shunt or unrepaired/palliated | |
| No. | 25 | 43 | |
| Male, n (%) | 15 (60) | 21 (49) | |
| Age (year) | 1.8 (1.5–3.7) | 1.9 (1.1–4.1) | ns |
| SpHb (g/dL) | 11.7 (10.7–12.5) n=17 | 12.9 (11.8–13.4) n=23 | P=0.02 |
| Baseline SpO2 (%) | 99 (99–100) | 87 (82–95) | P<0.0001 |
| Lowest test SpO2 (%) | 93 (91–94) | 78 (75–84) | P<0.0001 |
| Absolute drop in SpO2 (%) | 7 (6–8) | 8 (6–10) | P=0.03 |
| Time to reach lowest SpO2 (min) | 7 (5–10.8) n=15 | 6 (5–8) n=25 | ns |
| Baseline heart rate (bpm) | 121 (89–136) | 119 (107–134) | ns |
| Test heart rate (bpm) | 122 (97–131) | 121 (108–136) | ns |
| Change in heart rate (bpm) | 1 (−7 to +10) | 2 (−4 to +6) | ns |
| Baseline PtcCO2 (kPa) | 4.5 (4.4–4.9) n=24 | 4.1 (3.7–4.4) n=42 | P<0.0001 |
| Test PtcCO2 (kPa) | 4.6 (4.3–4.9) n=24 | 4.1 (3.6–4.4) n=41 | P=0.0005 |
| Change in PtcCO2 (kPa) | −0.1 (−0.2 to +0.2) | 0.0 (−0.3 to +0.2) | ns |
| Baseline QTc (ms) | 415 (399–428) n=21 | 406 (392–424) n=38 | ns |
| Test QTc (ms) | 421 (409–435) n=21 | 419 (399–425) n=38 | ns |
| Change in QTc (ms) | +5 (−6 to +25) n=21 | +6 (−5 to +23) n=38 | ns |
| Test failures, n (%) | 0 | 8 (19) | P=0.02 |
Results are expressed as median (IQR) unless stated otherwise. Data refer to the total patient numbers (n=25 and n=43 for the two groups) except where stated.
PtcCO2, partial pressure of carbon dioxide measured transcutaneously; QTc, QT interval corrected for heart rate; R–L, right to left; SpHb, total haemoglobin measured by pulse co-oximetry; SpO2, arterial oxygen saturation measured by pulse oximetry.