Evidence
This page contains a snapshot of featured content which highlights evidence addressing key clinical questions including areas of uncertainty. Please see the main topic reference list for details of all sources underpinning this topic.
BMJ Best Practice evidence tables
Evidence tables provide easily navigated layers of evidence in the context of specific clinical questions, using GRADE and a BMJ Best Practice Effectiveness rating. Follow the links at the bottom of the table, which go to the related evidence score in the main topic text, providing additional context for the clinical question. Find out more about our evidence tables.
This table is a summary of the analysis reported in a guideline (underpinned by a systematic review) that focuses on the above important clinical question.
Confidence in the evidence is very low or low where GRADE has been performed and the intervention may be more effective/beneficial than the comparison for key outcomes, however this is uncertain and new evidence could change this in the future.
Population: Children with or at risk of developing sepsis or severe sepsis
Intervention: Early initiation of empiric antimicrobial treatment
Comparison: Late initiation of empiric antimicrobial treatment
| Outcome | Effectiveness (BMJ rating)? | Confidence in evidence (GRADE)? |
|---|---|---|
<1 hour versus >1 hour ᵃ | ||
Pediatric Intensive Care Unit (PICU) mortality | No statistically significant difference | Very Low |
<2 hours versus >2 hours ᵃ | ||
PICU mortality | No statistically significant difference | Very Low |
<3 hours versus >3 hours ᵃ | ||
PICU mortality | Favors intervention | Very Low |
<4 hours versus >4 hours ᵃ | ||
PICU mortality | Favors intervention | Very Low |
Recommendations as stated in the source guideline For children aged 5–11 years who have suspected sepsis and 1 or more high-risk criteria, give a broad-spectrum antimicrobial ᵇ at the maximum recommended dose without delay (within 1 hour of identifying that they meet any high-risk criteria in an acute hospital setting).
Note The guideline group noted that the direct evidence in children came from one small (n=130), single-centre retrospective study of children in PICU with severe sepsis and septic shock. Therefore, they also extrapolated from the indirect evidence in adults to make the same recommendation for all age groups (including children aged under 5 years and 5-11 years). ᵃ Time from sepsis recognition to initial treatment and first appropriate treatment. ᵇ See full guideline for more information.
This evidence table is related to the following section/s:
This table is a summary of the analysis reported in a guideline (underpinned by a systematic review) that focuses on the above important clinical question.
Confidence in the evidence is very low or low where GRADE has been performed and the intervention may be more effective/beneficial than the comparison for key outcomes. However, this is uncertain and new evidence could change this in the future.
Population: Patients with suspected anaphylaxis
Intervention: One (earlier) timing of mast cell tryptase testing ᵃ
Comparison: Any other (later) timing ᵃ
| Outcome | Effectiveness (BMJ rating)? | Confidence in evidence (GRADE)? |
|---|---|---|
Timing of peak mast cell tryptase | See note ᵇ | Very Low |
End-point of elevated mast cell tryptase | See note ᶜ | Very Low |
Recommendations as stated in the source guideline After a suspected anaphylactic reaction in adults or young people aged 16 years or older, take timed blood samples for mast cell tryptase testing as follows: a sample as soon as possible after emergency treatment has started a second sample ideally within 1–2 hours (but no later than 4 hours) from the onset of symptoms.
Note The guideline committee stated that the timing of the first blood sample should be as soon as possible since the evidence suggests a median time of 30 minutes for the peak of mast cell tryptase and that the peak was reached within two hours in all but two patients. ᵃ The guideline committee did not identify any randomized controlled trials (RCTs) so they included observational studies. ᵇ The guideline committee noted that the timing of peak levels ranged from 1 minute to 6 hours (median 30 minutes, 7 studies, N=178) and that levels were reported as median 24 units per litre (range 4.09-66.2). ᶜ The guideline committee also noted the half-life of tryptase ranged from 30 minutes to 300 minutes (median 90 minutes, 6 studies, N=147) with levels returning to normal by 24 hours after onset of symptoms. Normal levels were reported at six hours in one study.
This evidence table is related to the following section/s:
This table is a summary of the analysis reported in a guideline (underpinned by a systematic review) that focuses on the above important clinical question.
Confidence in the evidence is very low or low where GRADE has been performed and the intervention may be more effective/beneficial than the comparison for key outcomes, however this is uncertain and new evidence could change this in the future.
Population: Adults with or at risk of developing sepsis or severe sepsis
Intervention: Early initiation of empiric antimicrobial treatment
Comparison: Late initiation of empiric antimicrobial treatment
| Outcome | Effectiveness (BMJ rating)? | Confidence in evidence (GRADE)? |
|---|---|---|
<1 hour versus >1 hour | ||
Mortality ᵃ | Favors intervention | Very Low |
Mortality - Intensive Care Unit (ICU) setting | Favors intervention | Very Low |
Mortality - Emergency Department (ED) setting | No statistically significant difference | Very Low |
<2 hours versus >2 hours | ||
Mortality ᵃ | No statistically significant difference | Very Low |
Mortality - ICU setting | Favors intervention | Very Low |
Mortality - ED setting | No statistically significant difference | Very Low |
<3 hours versus >3 hours | ||
Mortality ᵃ | Favors intervention | Very Low |
Mortality - ICU setting | No statistically significant difference | Very Low |
Mortality - ED setting | Favors intervention | Very Low |
<4 hours versus >4 hours | ||
Mortality - ED setting | No statistically significant difference | Very Low |
<5 hours versus >5 hours | ||
Mortality - ED setting | No statistically significant difference | Very Low |
<6 hours versus >6 hours | ||
Mortality ᵃ | Favors intervention | Very Low |
Mortality - ICU setting | No statistically significant difference | Very Low |
Mortality - ED setting | Favors intervention | Very Low |
Recommendations as stated in the source guideline The guideline committee recommends that adults, children and young people over the age of 12 who have suspected sepsis and one or more high risk criteria, should be given a broad-spectrum antimicrobial at the maximum recommended dose without delay (within 1 hour of establishing they meet high risk criteria in an acute hospital setting).ᵇ See guideline for details on criteria for different levels of risk.
Note Results in this table are based on observational studies only. ᵃ Includes overall mortality in intensive care and emergency department settings. ᵇ This guideline recommends that all people with suspected sepsis have a face-to-face assessment and a risk stratification tool is used to determine risk of severe illness and death from sepsis. Recommendations depend on the presence and number of high, moderate to high and low risk criteria.
This evidence table is related to the following section/s:
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