Table 1.
Observational Studies of Oxygenation in Critically Ill Adult Patients
| Study | Study Population* (n) | Oxygen Exposure Metric | Association of Hyperoxia and Mortality in Adjusted Models? |
|---|---|---|---|
| de Jonge et al. (2008) (42) | Receiving IMV (36,307) | PaO2 and FiO2 in first 24 h† | Yes |
| Eastwood et al. (2012) (43) | Receiving IMV (152,680) | PaO2 in first 24 h† | No |
| Rachmale et al. (2012) (44) | Patients with ALI receiving IMV for ⩾48 h (210) | Excessive FiO2 (FiO2 >0.5 with SpO2 >92%) | No |
| Helmerhorst et al. (2017) (45) | Patients with ⩾1 ABG (14,441) | Various‡ (i.e., mean/median PaO2 from ICU stay) | Yes |
| Kraft et al. (2018) (48) | IMV for ⩾7 consecutive d (20,889) | Time-weighted PaO2 over 7 d | No |
| Aggarwal et al. (2018) (46) | ARDS Network trials (all received IMV) (2,994) | Excessive FiO2 (FiO2 >0.5 with PaO2 >80 mm Hg) | Yes |
| Ramanan and Fisher (2018) (47) | Receiving IMV (219,732) | PaO2 in first 24 h§; analysis stratified by Hb | No |
| Ruggiu et al. (2018) (49) | ICU patients (130) | Any PaO2 >100 mm Hg during ICU admission | Yes |
| Palmer et al. (2019) (50) | ICU stay >24 h (45,188) | Time-weighted AUC for PaO2 >100 mm Hg | Yes |
| Harvey et al. (2020) (54) | Receiving IMV with ⩾3 ABGs (7,452) | Time-weighted CaO2 over ICU admission | Yes |
| Madotto et al. (2020) (51) | ARDS within 2 d of ICU admission (2,005) | PaO2 >100 mm Hg on ICU Day 1 | No |
| Schjørring et al. (2020) (52) | Receiving IMV (4,998) | Time-weighted AUC PaO2 >13.7 kPa (103 mm Hg) | Yes |
| van den Boom et al. (2020) (53) | All ICU admissions (124,984/46,476)‖ | Median SpO2 | Yes |
| Zhou et al. (2020) (55) | IMV in first 24 h of ICU (25,669) | Percentage of time spent at SpO2 of 100% | Yes |
Definition of abbreviations: a–a = alveolar–arterial; ABG = arterial blood gas; ALI = acute lung injury; APACHE = Acute Physiology and Chronic Health Evaluation; ARDS = acute respiratory distress syndrome; AUC = area under the curve; CaO2 = arterial oxygen concentration; IMV = invasive mechanical ventilation; SpO2 = oxygen saturation as measured by pulse oximetry.
All study samples include ICU patients only.
The PaO2 value was taken from blood gas with worst PaO2/FiO2 ratio in Reference 42 or from highest a–a gradient in Reference 43.
The purpose of the study was to evaluate multiple metrics; the mean/median PaO2 across the ICU stay had the strongest association with mortality.
Taken from the PaO2 value associated with highest APACHE score.
Sample sizes from replicate analyses of two retrospective cohorts.