Table 3. Daytime Assessments.
| Variable | Median (IQR) | Treatment Effect at 3100 m, Mean Difference (95% CI) | ||||||
|---|---|---|---|---|---|---|---|---|
| Placebo Group (n = 48) | Dexamethasone Group (n = 56) | |||||||
| 760 m | 3100 m | 760 m | 3100 m | Day 1 | Day 2 | |||
| Day 1 | Day 2 | Day 1 | Day 2 | |||||
| Karolinska sleepiness scorea | 3 (3 to 5) | 3 (3 to 5)b | 3 (3 to 5) | 3 (3 to 5) | 3 (3 to 5) | 3 (3 to 5) | −1 (−2 to 0) | 0 (−1 to 0) |
| Reaction time, ms | 344 (297 to 422) | 327 (286 to 393) | NA | 317 (279 to 408) | 336 (287 to 401) | NA | 38 (−28 to 104) | NA |
| Weight, kg | 73.0 (65.6 to 80.9) | 72.1 (65.7 to 79.2) | 73.2 (66.0 to 80.2) | 72.0 (63.0 to 80.0) | 70.5 (62.6 to 80.0) | 72.4 (63.3 to 80.7) | 0 (−1 to 1) | 0 (−1 to 0) |
| BP, mm Hg | ||||||||
| Systolic | 131 (111 to 141) | 128 (118 to 141) | 134 (120 to 142)b | 130 (112 to 142) | 126 (113 to 134) | 129 (120 to 141) | −5 (−10 to 0) | −3 (−9 to 3) |
| Diastolic | 82 (73 to 89) | 82 (74 to 86) | 82 (75 to 89) | 79 (73 to 87) | 77 (69 to 84)b,c | 81 (74 to 85) | −5 (−9 to −1) | −4 (−7 to 0) |
| Median (IQR) of the mean | 98 (87 to 105) | 96 (89 to 104) | 101 (91 to 107)b | 95 (87 to 107) | 91 (86 to 101)b,c | 97 (91 to 104) | −5 (−9 to −1) | −3 (−7 to 0) |
| Heart rate, bpm | 64 (59 to 70) | 68 (62 to 73)b | 66 (60 to 73) | 63 (58 to 70) | 67 (60 to 71)b | 59 (55 to 69)c | 0 (−3 to 3) | −4 (−7 to −1) |
| Arterial pH | 7.39 (7.38 to 7.41) | 7.42 (7.41 to 7.44)b | NA | 7.40 (7.39 to 7.42) | 7.43 (7.42 to 7.45)b,c | NA | 0.01 (0.00 to 0.02) | NA |
| Paco2, kPa | 5.1 (4.8 to 5.4) | 4.6 (4.4 to 4.9)b | NA | 5.2 (4.8 to 5.4) | 4.4 (4.1 to 4.7)b,c | NA | −0.2 (−0.4 to −0.1) | NA |
| Pao2, kPa | 10.0 (9.2 to 10.7) | 8.0 (7.8 to 8.4)b | NA | 9.6 (9.2 to 10.0) | 8.2 (7.9 to 8.7)b | NA | 0.5 (0.1 to 0.9) | NA |
| Sao2, % | 95 (93 to 95) | 89 (88 to 90)b | NA | 94 (93 to 95) | 90 (89 to 91)b,c | NA | 0.01 (0.00 to 0.02) | NA |
| DAaPo2, kPa | 3.1 (2.5 to 4.0) | 1.1 (0.5 to 1.5)b | NA | 3.6 (3.0 to 3.9) | 1.1 (0.6 to 1.4)b | NA | −0.2 (−0.6 to 0.2) | NA |
| HCO3, mEq/L | 23.3 (21.7 to 24.4) | 22.1 (20.8 to 23.0)b | NA | 23.2 (22.0 to 24.4) | 21.4 (20.6 to 22.8)b | NA | −0.6 (−1.4 to 0.1) | NA |
| Hematocrit, % | 44 (40 to 46) | 44 (41 to 46) | NA | 44 (41 to 46) | 44 (41 to 47)b | NA | 0 (0 to 0) | NA |
| Hemoglobin, g/dL | 14.8 (13.5 to 15.7) | 14.9 (13.8 to 15.6) | NA | 15.0 (13.8 to 15.8) | 14.9 (14.1 to 16.1)b | NA | 0.1 (−0.1 to 0.3) | NA |
| Glucose, mg/dL | 126.1 (108.1 to 144.1) | 133.3 (109.9 to 183.2) | NA | 120.7 (106.3 to 142.3) | 167.6 (140.5 to 205.4)b,c | NA | 52.3 (30.6 to 73.9) | NA |
| FEV1, L | 2.7 (2.3 to 3.0) | 2.6 (2.3 to 3.0) | 2.6 (2.1 to 2.9) | 2.5 (1.9 to 2.9) | 2.6 (1.9 to 2.9) | 2.5 (2.0 to 2.9) | 0.1 (0.0 to 0.2) | 0.1 (0.0 to 0.2) |
| % Predicted | 96 (77 to 109) | 93 (73 to 105) | 90 (79 to 105) | 85 (73 to 102) | 87 (74 to 103) | 90 (70 to 100) | 3 (−1 to 6) | 2 (−2 to 5) |
| FVC, L | 4.3 (3.7 to 4.9) | 4.1 (3.5 to 4.8) | 4.1 (3.5 to 4.8)b | 4.1 (3.3 to 4.5) | 4.2 (3.5 to 4.5) | 4.0 (3.3 to 4.6) | 0.1 (−0.1 to 0.2) | 0 (−0.1 to 0.1) |
| % Predicted | 122 (104 to 137) | 118 (99 to 136) | 121 (102 to 129) | 115 (98 to 125) | 114 (98 to 125) | 115 (97 to 126) | 2 (−2 to 5) | 0 (−3 to 4) |
| FEV1/FVC | 0.65 (0.60 to 0.68) | 0.65 (0.60 to 0.68) | 0.65 (0.59 to 0.68) | 0.63 (0.56 to 0.66) | 0.63 (0.60 to 0.68)b | 0.63 (0.58 to 0.68) | 0.01 (−0.01 to 0.03) | 0.01 (0.00 to 0.03) |
Abbreviations: BP, blood pressure; DAaPo2, alveolar-arterial Po2 difference23; FEV1, forced expiratory volume in the first second of expiration; FVC, forced vital capacity; HCO3, bicarbonate concentration; IQR, interquartile range; NA, not assessed; Paco2, partial pressure of carbon dioxide; Pao2, partial pressure of oxygen; Sao2, arterial oxygen saturation.
SI conversion factors: to convert glucose to millimoles per liter, multiply by 0.0555; HCO3 to millimoles per liter, multiply by 1; hematocrit to proportion of 1.0, multiply by 0.01; hemoglobin to grams per liter, multiply by 10.
Karolinska sleepiness score ranges from 1 (extremely alert) to 9 (very sleepy, great effort to keep alert, fighting sleep).
P < .05 vs 760 m.
P < .05 between dexamethasone and placebo at the corresponding altitude and day.