Primary and secondary outcomes
| Outcomes | Without aerosol box (N=36) | With aerosol box (N=36) | P value |
| Overall no. of contaminated participants* | |||
| Total no. of intubators with contaminations: | |||
| Pre-doffing | 36 (100.0%) | 36 (100.0%) | |
| Post-doffing | 13 (36.1%) | 16 (44.4%) | 0.607† |
| Total no. of assistants with contaminations: | |||
| Pre-doffing | 36 (100.0%) | 36 (100.0%) | |
| Post-doffing | 11 (30.6%) | 9 (25%) | 0.791† |
| Primary outcome | |||
| Number of body regions contaminated: | |||
| Pre-doffing | |||
| Intubator | |||
| Front, median (IQR)‡ | 13.0 (12.0–15.0) | 9.0 (7.0–11.0) | <0.001§ |
| Back, median (IQR)‡ | 13.0 (12.0–13.0) | 6.0 (4.0–8.0) | <0.001§ |
| Assistant | |||
| Front, median (IQR)‡ | 12.0 (9.0–13.8) | 7.0 (5.0–9.0) | <0.001§ |
| Back, median (IQR)‡ | 10.5 (6.0–13.0) | 6.0 (4.0–8.0) | <0.001§ |
| Post-doffing | |||
| Intubator | |||
| Front, median (IQR)‡ | 0.0 (0.0–1.0) | 0.0 (0.0–1.0) | 0.439§ |
| Back, median (IQR)‡ | 0.0 (0.0–0.0) | 0.0 (0.0–0.0) | 1.000§ |
| Assistant | |||
| Front, median (IQR)‡ | 0.0 (0.0–1.0) | 0.0 (0.0–0.0) | 0.380§ |
| Back, median (IQR)‡ | 0.0 (0.0–0.0) | 0.0 (0.0–0.0) | 0.714§ |
| Secondary outcomes | |||
| Intubator VL-CL score, no. (%) | |||
| Grade 1 | 19 (52.8%) | 20 (55.6%) | 0.753¶ |
| Grade 2a | 8 (22.2%) | 10 (27.8%) | |
| Grade 2b | 8 (22.2%) | 6 (16.7%) | |
| Grade 3 | 1 (2.8%) | 0 | |
| Grade 4 | 0 | 0 | |
| Assessor VL-CL score, no. (%) | |||
| Grade 1 | 17 (47.2%) | 21 (58.3%) | 0.273¶ |
| Grade 2a | 16 (44.4%) | 13 (36.1%) | |
| Grade 2b | 3 (8.3%) | 2 (5.6%) | |
| Grade 3 | 0 | 0 | |
| Grade 4 | 0 | 0 | |
| Median intubation time, s (IQR) | 35.5 (29.3–42.6) | 42.5 (35.9–47.6) | <0.001§ |
| Intubation attempts, no. (%) | |||
| 1 | 36 (100%) | 34 (94.4%) | |
| 2 | 0 | 2 (5.6%) | |
| Room contamination radius, m (±SD) | 1.62 (±0.59) | 1.10 (±0.49) | <0.001** |
Kruskal-Wallis analyses of the difference in video laryngoscope Cormack-Lehane (VL-CL) score between the Assessor and the Intubators yielded no significant difference for both with and without the intubation box (p=0.157 and p=0.135, respectively).
*Having at least one body region contaminated.
†Analysis performed with McNemar test.
‡Out of a total number of 15 body regions for the front and 15 body regions for the back.
§Analysis performed with Wilcoxon signed rank test (data not normally distributed).
¶Analysis performed with McNemar-Bowker test (for VL-CL Grade 1, 2a and 2b).
**Analysis performed with paired t test (data normally distributed).