Table 2.
Scientific quality of trials of inhaled nitric oxide (NO) in patients with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS)*
| Author | Allocation concealment | Blinding | Ventilation | Other cointerventions |
|---|---|---|---|---|
| Day,w1 1997 | Blinded draw of 1 lot per eligible patient | None | Clinician discretion | Not described |
| Schwebel,w2 1997 | Table of gas cylinder codes (revealed in sequence) | Clinicians, outcomes assessors | Protocol (no details) for 17 hours; clinician's discretion thereafter | Not described |
| Dellinger,w3 1998 | Sealed, opaque envelopes | Clinicians†, outcomes assessors | Guideline (Pplat≤35 cm H2O; PEEP to optimise compliance; FiO2 minimised) | More patients in NO group received corticosteroids after day 6 (20/112 v 6/57) |
| Michael,w4 1998 | Not reported | None | Clinician discretion; mode unchanged for 72 hours; mean PEEP similar between groups for 72 hours | Not described |
| Troncy, w5 1998 | Envelopes‡ | None | Protocol (VT 10 ml/kg and goal PaCO2 35-45 mm Hg; maximum PEEP 15 cm H2O and goal PaO2 >85 mm Hg) | Sedation, blood transfusion, and nutrition protocols. No prone ventilation in any patient |
| Dobyns,w6 1999 | Envelopes‡ | Clinicians†, outcomes assessors | Guideline (“open lung approach” with Ppk ≤35-40 cm H2O, VT limitation, titrated PEEP; HFOV by clinician discretion) | Not described |
| Lundin,w7 1999 | Central | None | Clinician discretion | Not described |
| Payen,w8 1999 | Central | Clinicians, outcomes assessors | Guideline before randomisation; unclear if applied afterwards (VT, Pplat, Ppk limitation; various recruitment strategies) | Not described |
| Mehta,w9 2001 | No§ | None | Clinician discretion | No prone ventilation in any patient |
| Gerlach,w10 2003 | Envelopes‡ | None | Protocol (no details) | Protocol for prone ventilation and extracorporeal membrane oxygenation |
| Park,w11 2003 | One random number generated when patient eligible | None | Protocol (VT 6 ml/kg; Pplat ≤30 cmH2O; PEEP to optimise PaO2; FiO2 minimised) | Weaning protocol. No prone ventilation in any patient |
| Taylor,w12 2004 | Central | Clinicians†, outcomes assessors | Guideline (Pplat ≤ 35 cm H2O; PEEP to optimise compliance; FiO2 minimised) | Prone ventilation similar (NO: 10/192 and control: 14/193), weaning protocol |
FiO2=fraction of inspired oxygen; HFOV=high frequency oscillatory ventilation; PaO2=partial pressure of arterial oxygen; PaCO2=partial pressure of arterial carbon dioxide; Pplat=plateau airway pressure; Ppk=peak airway pressure; PEEP=positive end expiratory pressure; VT=tidal volume.
*No study reported withdrawals of patients or loss to follow-up for mortality; all patients analysed according to assigned group.
†Unblinded investigator at each site.
‡Envelopes sealed, sequentially numbered, and opaque.
§Computer generated random numbers. Investigator had access to entire randomisation list at time of randomisation.