S	Search history
S1	(SU "Critical Care") or (SU "Intensive Care") or (SU "Intensive Care Units") or (SU "Coronary Care") or (SU "Life Support Care") or (SU "Critical Illness") or (TX "critical care") or (TX "intensive care") or (TX "coronary care") or (TX "cardiothoracic") or (TX (ICU or ITU or CCU or CTU)) or (TX "critical* ill*")
S2	(SU "Ventilators Mechanical") or (SU "Respiration Artificial") or (TX "mechanical* ventilat*") or (TX "artificial* respirat*") or (TX "positive pressure ventilat*") or (TX "non‐invasive ventilat*" or "non invasive ventilat*")
S3	S1 or S2
S4	(TX "lateral position*") or (TX "lateral rotat*") or (TX "lateral recumben*") or (TX "lateral turn*") or (TX "lateral decubit*") or (TX "lateral tilt*") or (TX "side lying") or (TX "side position*") or (( TI "lateral" or AB "lateral" ) and SU "Posture") or (TI "dependent position*" or AB "dependent position*")
S5	(SU "Prone Position") or (SU "Supine Position") or (SU "Head‐down Tilt") or (TX "supine position*") or (TX "dorsal position*") or (TX "recumben*") or (TX "horizontal position*") or (TX "prone position*") or (TX "ventral decubit*") or (TX "head down*") or (TX "head tilt*") or (TX "Trendelenburg*") or (TX "vertical position*") or (TX "degree* position*") or (TX "backrest elevat*") or (TX "head elevat*") or (TX "Fowler*") or (TX "semi recumben*") or (TX "sitting") or (TX "upright position*") or (( TI position* or AB position* ) and SU "Posture")
S6	S4 or S5
S7	S3 and S6