Langhan 2015.

Methods	Design: prospective RCT Blinding: research associates unblinded, participants and personnel unblinded, allocation concealed Dates: September 2011 to January 2013.
Participants	n = 154 Included: paediatric participants (aged 1 to 20 years) requiring PSA Excluded: intubation, administration of baseline supplemental oxygen without preceding hypoxaemia, and conditions associated with abnormal ETCO2 values such as lower airway disease (e.g. asthma), diabetic ketoacidosis, moderate to severe dehydration, and major trauma. Participants were excluded if they did not tolerate the capnography cannula or if the participant cried for > 20% of the sedation Location: paediatric emergency department, tertiary care university hospital, US
Interventions	Control (n = 77) Standard monitoring (cardiac monitoring, pulse oximetry, and blood pressure monitoring) and blinded capnography Intervention (n = 77) Standard monitoring and capnography (alerts at ETCO2 levels of < 30 mmHg and > 50 mmHg)
Outcomes	Primary Oxygen desaturation (SpO2 < 95%) Airway interventions (verbal or physical stimulation, bag‐valve mask ventilation, jaw thrust, head tilt, use of a shoulder roll, supplemental oxygen, or reversal agents)* Secondary Oxygen desaturation (SpO2 < 90%)**
Funding sources	Research grant from government organization (National Center for Advancing Translational Science, components of the National Institutes of Health)
Declarations of interest	Not stated in publication
Notes	*Airway interventions: verbal or physical stimulation, bag‐valve mask ventilation, airway repositioning (jaw thrust or head tilt), use of a shoulder roll, supplemental oxygen or reversal agents **Primary outcome was SpO2 < 95%. Secondary outcome SpO2 < 90% obtained by contacting author directly.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	A statistician provided blocked randomization using Proc Plan (Sas 9.2, Cary, NC), with a 7‐digit random seed; group assignments were allocated to participants in a random sequence within blocks of 6.
Allocation concealment (selection bias)	Low risk	Allocation concealed with sealed, opaque envelopes.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants and personnel not blinded to capnography screens.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Research associates during procedures not blinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Outside of a priori defined exclusion criteria, all data included.
Selective reporting (reporting bias)	Low risk	All participant outcomes accounted for upon contacting author directly.
Other bias	Low risk	Unpublished data for the oxygen desaturation outcome was obtained from author. Funding: supported by an independent government grant.

ETCO₂: end‐tidal carbon dioxide partial pressure; n: number of participants; PSA: procedural sedation and analgesia; RCT: randomized controlled trial; SBP: systolic blood pressure; SpO₂: blood oxygen saturation.