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Effectiveness of respiratory rates in determining clinical deterioration

a systematic review protocol

Mlgaard, Rikke Rishj; Larsen, Palle; Håkonsen, Sasja Jul

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JBI Database of Systematic Reviews and Implementation Reports: July 2016 - Volume 14 - Issue 7 - p 19-27
doi: 10.11124/JBISRIR-2016-002973
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It is a universal practice to measure vital signs in patients at the time of admission in hospitals. Measurement of vital signs has been found to be important and useful in detecting clinical deterioration of inpatients.1–5 “A deteriorating patient is one who progresses from one clinical state to a worse clinical state which increases their individual risk of morbidity, including organ dysfunction, protracted hospital stay, disability, or death.”6(p.1031) Different types of early warning scoring systems for clinical deterioration have been developed and evaluated. A Cochrane review published in 20077 concluded that implementation of early warning scoring systems is complex and its impact on practice can be variable. Although algorithms for nurses’ interventions following measurement of vital signs have been developed, it was found that nurses’ knowledge base and skills are lacking, particularly with regard to the rationale for the measurement of vital signs and how to respond adequately to these measurements.7–10

It is widely acknowledged that detecting clinical deterioration early is vital in avoiding intensive care unit (ICU) admission or cardiac arrest and death, sepsis and other acute clinical conditions.2–4,11 An increase in respiratory rates can often be detected several hours before other signs as the first indication of deterioration.11,12 Measurement of respiratory rate as a vital sign is important in detecting deterioration, as the respiratory rate often increases before other vital signs show deterioration.1,5,12–15 Studies have shown an increase in respiratory rates of up until 24 h prior to ICU admission.16,17

Nurses do not measure respiratory rates routinely for many reasons.5,9,15 A qualitative study has highlighted that nurses tend not to measure the respiratory rate if they judge that the patient's condition is stable. In cases where nurses do measure the respiratory rates, they do not do so for a full minute because it takes too much time, it is likely to be interrupted or the patient becomes agitated. It has also been noted that the reason for respiratory rate measurement being omitted is that some nurses do not think that it is important to measure the respiratory rate routinely.10 Another issue with regard to the measurement of the respiratory rate is the heterogeneity in the technique of measuring respiratory rates by medical and nursing professionals. This, in turn, has generated a wide range of respiratory rates and as a consequence of this, important information about the patient's condition lacks an adequate clinical response.1

It is considered best practice for manual measurement of respiratory rates to be carried out over a full minute to gain an effective measurement.1,11,14,18–20 However, several methods were described in the literature in which the rates were measured over a period of 15, 30 or 60 seconds. In one study, it was found that there was a significant difference between a manually measured rate and a recorded rate as the recorded rate was often likely to be 18 and 20 per minute, which was higher than a manually measured rate and was considered as a high rate.3 This indicates an overrepresentation of even values when respiratory rates are recorded. A respiratory rate of more than 20 is defined as tachypnoe.19 It was also found that, if the respiratory rate increases by more than three to five respirations per minute from the patient's normal rate, it is a sign of clinical deterioration relating to respiratory distress or potential hypoxemia.11

A measurement of respiratory rate considered appropriate is to count for a full minute to assess the respiratory condition and to detect clinical deterioration. Measurement of respiratory rates includes counting the number of breaths, usually per minute. The patient is unaware of the counting of the respiratory rate. As the respiratory rate is one of the first signs of deterioration, it is important to measure the respiratory rate accurately.1,3,8,21 It is therefore important to evaluate whether a difference in the duration of manually measured respiratory rates (for a full minute or less than 60 seconds) has an impact on clinical practice in detecting clinical deterioration.

Finally, the issues of lack of knowledge base, and competency in undertaking measurement and interpreting the respiratory rates by nursing professionals were also highlighted in the literature.10 However, other studies demonstrated that it was possible to increase the number of measured and recorded respiratory rates and vital signs if nurses were taught how and why it is important, and this intervention was shown to be ratified at follow-up in the way that respiratory rates were more often measured and recorded.2,5,9,15 Bunkenborg9 showed in 2014 that the development and implementation of a bedside track and trigger system to detect clinical deterioration had an effect in the prevention of unexpected death and consequently a positive effect on patient safety. Bunkenborg also asserted that, in consideration of the beneficial effects of measuring the respiratory and heart rates, it might benefit patient safety to ensure optimization of these two vital signs.9 It is therefore important to investigate if this optimization could include how the respiratory rate is manually measured.

It is important to determine whether measurement of respiratory rate for a full minute or less has an impact on the detection of clinical deterioration. It is asserted that an increase of three to five respirations per minute may constitute a sign of clinical deterioration. If the respiratory rate is counted for less than 60 seconds, there is a risk of overlooking an increase in the total respiratory rate, and signs of deterioration are at risk of being overlooked. It is argued that an increase in respiratory rates often deteriorates before other vital signs. It is therefore important to synthesize knowledge on best practice in accordance with the correct method to measure respiratory rates to optimize detection of clinical deterioration so that ICU admission, cardiac arrest, sepsis and other acute clinical conditions can be reduced.

An initial search of the topic in the databases CINAHL, The Cochrane Library, The JBI Database of Systematic Reviews and Implementation Reports and PubMed did not identify previous reviews. Systematic reviews of topics regarding vital sign measurement and different types of early warning scoring systems exist, but none of them investigate the topic described in this review protocol.

Inclusion criteria

Types of participants

The current review will consider studies that have included adult patients aged at least 18 years admitted to a surgical or medical ward and who therefore have had their respiratory rates measured in the ward to detect clinical deterioration.

Types of interventions

The current review will consider studies that have evaluated manual measurement of respiratory rates for a full minute compared with durations of less than 60 seconds. Studies that may have measured respiratory rates for more than 60 seconds will, when appropriate and relevant to the review question, be analyzed and included in the discussion of the results.


Clinical deterioration can be measured by physiologic instability as abnormal values of vital signs such as tachypnea, tachycardia, hypotension and decreased oxygen saturation.13,19 This review will consider studies that include the following outcome measures: respiratory rate, blood pressure, pulse rate, oxygen saturation and temperature, all of which are considered as the actual measurement (continuous data). Mortality will also be considered if reported in the included studies.

Types of studies

The current review will consider any experimental study designs for inclusion, including randomized controlled trials, non-randomized controlled trials, quasi-experimental, before and after studies, prospective and retrospective cohort studies, case-control studies and analytical cross-sectional studies.

Search strategy

The search strategy has the aim of finding both published and unpublished studies. A three-step search strategy will be utilized in this review. An initial limited search of PubMed and CINAHL will be undertaken, followed by analysis of the text words contained in the title and abstract, and of the index terms used to describe the article. A second search, using all identified keywords and index terms, will then be undertaken across all included databases. Third, the reference list of all identified reports and articles will be searched for additional studies. Studies published in Danish, English, Norwegian and Swedish will be considered for inclusion in this review. No date limits will be applied to the search.

The databases to be searched include: PubMed, CINAHL, Embase, Scopus, Science Direct and SweMed+.

The search for unpublished studies will include: MedNar, Google Scholar, Trip database, the National Institute of Health and Care Excellence and National Patient Safety Agency databases.

Initial keywords to be used will be: ward patient, inpatient, respiratory rate, breathing rate, measuring, measurement, measure, deteriorate, deteriorating, deterioration, adverse event.

Assessment of methodological quality

All studies identified in the database search will be appraised for relevance to the review by title and abstract. Following this, the papers will be retrieved in full text to appraise the relevance according to the inclusion criteria with regard to the review question.

Papers selected for retrieval will be assessed by two independent reviewers for methodological validity prior to inclusion in the review, using standardized critical appraisal instruments from the Joanna Briggs Institute Meta Analysis of Statistics Assessment and Review Instrument (JBI-MAStARI) (Appendix I). Any disagreements that arise between the reviewers will be resolved through discussion or with a third reviewer.

Data extraction

Data will be extracted from papers included in the review using the standardized data extraction tool from JBI-MAStARI (Appendix II). The data extracted will include specific details about the interventions, populations, study methods and outcomes of significance to the review question and specific objectives.

Data synthesis

Quantitative data will, in possible cases, be pooled in statistical meta-analysis using JBI-MAStARI. All results will be subject to double data entry. Effect sizes expressed as odds ratios (for categorical data) and weighted mean differences (for continuous data), and their 95% confidence intervals will be calculated for analysis. Heterogeneity will be assessed statistically using the standard Chi-square. In cases in which statistical pooling is not possible, the findings will be presented in narrative form, including tables and figures, to aid in data presentation in appropriate cases.

Appendix I: Appraisal instruments

MAStARI appraisal instrument


Appendix II: Data extraction instruments

MAStARI data extraction instrument



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Detection of clinical deterioration; inpatients; nursing; respiratory rate measurement; vital sign measurement

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