Methods
For this scoping review, a systematic search of scientific literature was executed.
Information sources and search strategy
First, an explorative Cochrane search was performed on July 13, 2023 to identify any existing reviews on noncontact respiration monitoring methods in children. To this extent, the keywords “child*” “monitor*” and “breath*” were used for a search in titles, abstracts and keywords. No reviews focusing on noncontact respiration monitoring methods in children were found.
Next, a systematic literature search in PubMed and EMBASE was performed July 13, 2023. The search strings (E-text 1 and 2) included the same terms as the Cochrane search, supplemented with similar terms and synonyms. Terms regarding unobtrusiveness were also included. In this process, a librarian specialized in medical sciences was consulted.
Inclusion and exclusion criteria
For this review, ‘contactless’ also encompassed sensors embedded in natural sleeping attributes, such as mattresses and pajamas. Studies had to at least measure apneas and/or hypopneas or RR. Furthermore, studies had to include, but were not restricted to, children who were <12 years of age. Studies were excluded if obtrusive, contact, prediction or indirect methods were used, if subjects were premature infants, and if subjects were nonhuman. Reviews, conference abstracts, questionnaires and commentaries were also excluded. Lastly, only full-text articles written in English were eligible for inclusion.
Study selection
Following the search, EndNote10 (Clarivate Analytics, London, UK) was used to remove duplicates, after which the remaining studies were uploaded into Rayyan11 (Rayyan Systems, Inc., Cambridge, MA). Study relevance was assessed by title and abstract screening, after which full-text articles were read to determine eligibility based on the inclusion and exclusion criteria. This was done independently by two reviewers (ML and RG), and any disagreements were discussed until consensus was reached. If no consensus was reached, disagreements were resolved by discussing them with a third reviewer (JD). This, however, did not occur. Finally, the reference lists as well as the citations of all included papers were checked to identify additional eligible studies.
Data extraction and synthesis
Outcome data that was aimed to extract from the studies included data on the accuracy, safety, and reliability of the proposed methods. The results were summarized in a narrative synthesis.
Quality assessment
The quality of the included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool12. The QUADAS-2 tool allows analysis of the risk of bias and applicability specific to diagnostic accuracy reviews. Four domains were included: patient selection, index test, reference standard, and flow and timing. The risk of bias and applicability concerns were reported as low, high or unclear. The tool was adapted to fit the purposes of this review. The number of study participants was taken into consideration in the quality assessment. If less than ten study participants were included, the risk of bias caused by patient selection was assessed to be high. A risk of bias was assessed to be unclear if the researchers did not provide enough information to evaluate the risk. If no reference standard was used, both the risk of bias of the reference standard and of the flow and timing were assessed to be high risk.