Characteristics of included neonates
| Characteristics | Cohort (n=174) |
| Gestational age (weeks), mean (SD) | 37.5 (2.8) |
| Birth weight (g), mean (SD) | 3080 (723) |
| Sex (male), n (%) | 112 (64) |
| Plurality (multiple), n (%) | 16 (9) |
| Mode of birth, n (%) | |
| Vaginal | 75 (43) |
| Elective caesarean section | 33 (19) |
| Emergency caesarean section | 66 (38) |
| Apgar at 5 min, median (IQR) | 9 (7–9) |
| Intermittent positive pressure ventilation at birth, n (%) | 56 (32) |
| Underlying lung disease, n (%) | |
| None | 79 (45) |
| Hyaline membrane disease | 68 (39) |
| Transient tachypnoea of newborn | 14 (8) |
| Meconium aspiration syndrome | 10 (6) |
| Pulmonary hypoplasia | 1 (0.6) |
| Congenital pneumonia | 1 (0.6) |
| Other | 1 (0.6) |
| Age at time of pneumothorax diagnosis (hours), median (IQR) | 14.5 (2–28) |
| Diagnosis modality, n (%) | |
| Radiograph | 169 (97) |
| Transillumination alone | 5 (3) |
| Ultrasound | 0 (0) |
| Type of pneumothorax | |
| Right | 70 (40) |
| Left | 79 (45) |
| Bilateral | 25 (14) |
| Distance of referring unit (km),* n (%) | |
| 0–60 | 118 (68) |
| 61–160 | 34 (20) |
| >161 | 22 (13) |
| Remoteness area of referring unit,† n (%) | |
| Major cities | 130 (75) |
| Inner regional | 37 (21) |
| Outer regional | 7 (4) |
| Level of defined care capability of referring unit,‡ n (%) | |
| Levels 1 and 2 | 9 (5) |
| Level 3 | 27 (16) |
| Level 4 | 65 (38) |
| Level 5 | 30 (17) |
| Level 6 | 0 (0) |
| Private | 42 (24) |
| Level of defined care capability of receiving unit,‡ n (%) | |
| Level 4 | 3 (1.7) |
| Level 5 | 1 (0.6) |
| Level 6a | 95 (55) |
| Level 6b | 75 (43) |
| Mode of transport from referring unit, n (%) | |
| Road ambulance | 151 (87) |
| Rotary wing | 5 (3) |
| Fixed wing | 18 (10) |
| Duration of stabilisation (hours), median (IQR) | 2 (1.2–2.7) |
| Duration of travel (hours), median (IQR) | 1 (0.6–1.8) |
*Distance of referring unit grouped by straight line distance from Melbourne General Post Office: metropolitan (<60 km), inner regional (61–160 km) and rural (>161 km).
†Remoteness area defined by Australian Institute of Health and Welfare’s Hospital peer groups.
‡Referring unit neonatal care capability as defined by Department of Health, Victoria. Level 1–3 units provide care for mild to moderately unwell neonates of ≥34 weeks’ gestation or ≥2000 g BW, with 72 hours of CPAP being able to be provided in level 3 units with oxygen requirement less than 30%. Level 4 units provide care for neonates of ≥32 weeks’ gestation or ≥2000 g BW who are moderately unwell, with 96 hours of CPAP being able to be provided in level 3 units with oxygen requirement less than 40%. Level 5 units provide care for neonates of ≥31 weeks’ gestation or ≥1250 g, with CPAP being able to be provided when oxygen requirement does not exceed 50%. Level 6 units are tertiary intensive care units, with level 6a offering medical care only and level 6b offering both medical and surgical care.
Apgar, appearance, pulse, grimace, activity and respiration; BW, birth weight; CPAP, continuous positive airway pressure.