S	Search history
S1	(MH "Critical Care+") or (MH "Critical Care Nursing+") or (MH "Life Support Care") or (MH "Critical Illness") or (MH "Critically Ill Patients") or (MH "Intensive Care Units+") or "critical care" or "intensive care" or "coronary care" or "cardiothoracic unit" or (ICU or ITU or CCU or CTU) or "critical* ill*"
S2	(MH "Ventilation, Mechanical+") or "mechanical ventilat*" or "artificial* respirat*" or "positive pressure ventilat*" or "noninvasive ventilat*" or "non invasive ventilat*"
S3	S1 or S2
S4	"lateral position*" or "lateral rotat*" or "lateral recumben*" or "lateral turn*" or "lateral decubit*" or "lateral tilt*" or "side lying" or "side position*" or ((TI lateral or AB lateral) and MH "POSTURE+") or ((TI lateral or AB lateral ) and MH "Patient Positioning") or ((TI dependent position* or AB dependent position*))
S5	(MH "Patient Positioning+") or "supine position*" or "dorsal position*" or recumben* or "horizontal position*" or "prone position*" or "ventral decubit*" or "head down*" or "head tilt*" or Trendelenburg or "vertical position*" or degree* position* or "backrest elevat*" or "head elevat*" or semi‐Fowler* or Fowler* or semi recumben* or semirecumben* or sitting or "upright position*" or ((TI position* or AB position*) and MH "POSTURE+")
S6	S4 or S5
S7	S3 and S6
S8	(PT Clinical Trial) or "random* control* trial*" or (MH "Random Sample+") or (MH "Double‐Blind Studies") or (MH "Single‐Blind Studies") or (MH "Clinical Trials+") or (TI clinical trial* or AB clinical trial*) or (TI (singl* or doubl* or trebl* or tripl*) and (blind* or mask*)) or (AB (singl* or doubl* or trebl* or tripl*) and (blind* or mask*)) or (MH Placebos) or (TI placebo* or AB placebo*) or (TI random* or AB random*) or (MH "Quantitative Studies+") or (MH "Crossover Design") or (MH "Quasi‐Experimental Studies+") or (MH "Comparative Studies") or (MH "Evaluation Research") or (MH "Prospective Studies") or (TI (control* or prospectiv* or volunteer*) or AB (control* or prospectiv* or volunteer*))
S9	S7 and S8