Supplemental Material 2: search strategy
Unless otherwise stated, search terms are free text terms. Abbreviations: ’$’: stands for any character; ’?’: substitutes one or no character; adj: adjacent (i.e. number of words within range of search term); exp: exploded MeSH; MeSH: medical subject heading (MEDLINE medical index term); pt: publication type; sh: MeSH; tw: text word.
The selected terms for the analysis are divided in two groups: Group 1 contains terms pertaining CPR combined with the Boolean operator OR, and Group 2 comprehends the words “backboard”
and “board” combined with the Boolean operator OR. These two groups are combined with the Boolean operator AND for the search.
The Cochrane Library
#1 ("CPR"):ti,ab,kw OR ("cardiac arrest"):ti,ab,kw OR ("cardio pulmonary
resuscitation"):ti,ab,kw OR ("cardiac massage"):ti,ab,kw AND (chest compression):ti,ab,kw in Cochrane Reviews, Cochrane Protocols, Trials, Clinical Answers, Editorials, Special ;
#2 (backboard):ti,ab,kw OR (board):ti,ab,kw in Cochrane Reviews, Cochrane Protocols, Trials, Clinical Answers, Editorials, Special collections
#3 #1AND#2
MEDLINE (PubMed)
(("backboard"[Title/Abstract]) OR (“board”[Title/Abstract]) AND (("cpr"[Title/Abstract]) OR ("cardiac arrest"[Title/Abstract]) OR (“cardio pulmonary resuscitation”[Title/Abstract]) OR (“cardiac massage”[Title/Abstract]) OR ("chest compression"[Title/Abstract]))
Scopus
((TITLE-ABS-KEY(board)) OR (TITLE-ABS-KEY(backboard))) AND ((TITLE-ABS-KEY(
CPR)) OR (TITLE-ABS-KEY("cardiac arrest")) OR (TITLE-ABS-KEY("cardio
pulmonary resuscitation")) OR (TITLE-ABS-KEY("cardiac massage")) OR (TITLE-ABS-KEY("
chest compression")))
Google Scholar (search was limited to titles)
allintitle:((board) OR (backboard)) AND ((CPR) OR ("cardiac arrest") OR ("cardio pulmonary resuscitation") OR ("cardiac massage") OR ("chest compression"))
clinicaltrials.gov
((board) OR (backboard)) AND ((CPR) OR ("cardiac arrest") OR ("cardio pulmonary resuscitation") OR ("cardiac massage") OR ("chest compression"))
For grey literature search:
metaRegister of Controlled Trials
((board) OR (backboard)) AND ((CPR) OR ("cardiac arrest") OR ("cardio pulmonary resuscitation") OR ("cardiac massage") OR ("chest compression"))
OpenSIGLE repository
((board) OR (backboard)) AND ((CPR) OR ("cardiac arrest") OR ("cardio pulmonary resuscitation") OR ("cardiac massage") OR ("chest compression
For further details, please refer to the protocol, registered under the code “CRD42019119904” on http://www.crd.york.ac.uk/prospero/
Deviations from the study protocol Type of deviation: addition
"CPR not performed by humans" was added to exclusion criteria to isolate only data derived from manual chest compressions since the mechanical chest compressions is considered only a
supplemental treatment in an overall strategy for treating cardiac arrest patients. CPR performed by humans is still the most available form of resuscitation and an important source of performance variability in real clinical situations.
[see: Li H, Wang D, Yu Y, Zhao X, Jing X. Mechanical versus manual chest compressions for cardiac arrest: a systematic review and meta-analysis. Scand J Trauma Resusc Emerg Med. 2016 Feb 1;24:10].
