Peter McCanny

Rationale: - ‘little evidence to guide clinicians regarding optimal timing for tracheostomy in ICUs’.

Objective: - To test whether ‘early’ vs ‘late’ tracheostomy would result in lower mortality in adult patients receiving mechanical ventilation (MV).

Design:- Open multicentre RCT, 2004- 2011 - 72 ICU’s in UK (70 general/ 2 cardiothoracic;

13 university/ 59 non-uni)

Participants:- 909 patients: MV <4 days- Identified by treating physician as likely to require >7days MV

Interventions:- Randomised to receive ‘early’ (within 4 days) or ‘late’ (after 10 days, if still indicated) tracheostomy.

Outcome measures:- Primary outcome= 30 day mortality- Intention to treat analysis

‘For adult patients on MV in UK ICU’s, trachy within 4 days of critical care admission was not associated with

improvement in 30d mortality, or other important secondary outcomes’

‘Early tracheostomy should be avoided unless tools to accurately predict the duration of mechanical ventilation on

individual patients can be developed and validated’

• Sponsorship/ conflicting interests of authors?

- Funded by UK Intensive Care Society and Medical Research Council (UK).

- No industry involvement.

• Journal?

• Authors?

• RECRUITMENT:

- Were study subjects representative of the target population?

- POSSIBLY

(12%)

• RECRUITMENT- Was sample adequately powered?

- Pilot studies performed.

- Adjusted during study following updated data in systematic review (2006).

- Final planned sample size of 1692 patients to detect a 6.3% absolute (21% relative ) reduction in mortality.

- INTENDED SAMPLE SIZE NOT REACHED: ‘final 899- patient study had the power to detect an 8.3%

absolute change in 30-day mortality from the late group value of 31.5% with 80% power and 5% level of significance.’

• ALLOCATION:- Was the randomisation method unbiased?

- YES- Automated 24hr phone service, using algorithm to minimise imbalance between groups (centre, age, sex, diagnostic groups).

- Were the groups matched as closely as possible at start of trial?

• MAINTENANCE:

- Was comparable treatment of the 2 groups maintained throughout the study?

- NO:

- ‘EARLY ‘ group: 85% of patients had trachy within 4 days.- ‘EARLY’ group: 6.8% did not receive trachy at all.- ‘LATE’ group: 54% did not receive trachy at all!

- Was transparent information provided to show how and where subjects were ‘lost’ during the trial?

• - YES: detailed in methods and results sections.

• MAINTENANCE:

- Was transparent information provided to show how and where subjects were ‘lost’ during the trial?

- YES- Detailed in methods and results sections.

•BLINDING:- Were outcomes measured with blinded subjects and

assessors?

- NO- Caring team and analysis team not blinded, by nature

of study design.- Subjects/ relatives not blinded (consent had to be provided).

• OBJECTIVITY OF OUTCOME MEASUREMENT:- Were outcomes measured objectively?

PRIMARY OUTCOME: - 30- day mortality…..YES

SECONDARY OUTCOMES:- ICU, hospital discharge mortality….YES- 2yr mortality….YES (note: added post- hoc)- Duration of mechanical ventilation….YES- Use of sedatives….YES

• Could the effect have been due to chance?

• What measure was used and how large was the treatment effect?

• Are the conclusions valid?- Debatable, given issues around change in sample size, powering.

• External validity and Generalisability of results to our population?- UK system different from ours (occupancy, bed

pressures etc)- High proportion of ‘Non- University hospitals’- High overall mortality rates (sick patients)

- Similar patient cohort (except neurosurg), mostly perc trachy, performed by senior physicians.

• Ability of physicians to predict which patients will require MV > 7 days may be unreliable.

• Despite flaws in study (especially underpowering)- it included large patient numbers, with a transparent analysis, and provides us with useful data.

• Early tracheostomy is probably unnecessary in most patients who require mechanical ventilation for respiratory failure.

• This is in keeping with findings of other randomised studies on timing of trachy insertion.

Background:

- Percutaneous dilational tracheostomy (PDT) frequently performed by Intensivists in adult ICU’s.

- Complications rare but serious (including perforation, death)

- Realtime Ultrasound (US) guidance has been proposed to decrease complications and improve accuracy of tracheal puncture.

Methods:

- 50 patients receiving PDT were randomly assigned to have tracheal puncture carried out using either traditional anatomical landmarks or real-time US guidance.

- Puncture position recorded using bronchoscopy.

- Blinded assessors determined the deviation of puncture off midline, and whether appropriate longitudinal position (between 1st- 4th tracheal rings) was achieved.

Results:

Anatomical Ultrasound Stats

Mean deviation from midline (degrees)

35 (+/- 5) 15 (+/- 3) p= 0.001

Proportion of ‘appropriate’ punctures (0-30 degrees)

50% 87% RR= 1.74(CI’s 1.13- 2.67)p= 0.006

1st pass success rate 58% 87% RR= 1.49(CI’s 1.03- 2.07)p= 0.028

Complication rate 37% 22% RR= 0.58(CI’s 0.23- 2.47)p= 0.24

Conclusions:

- US guidance significantly improved the rate of 1st pass puncture and puncture accuracy.

- Fewer complications were observed, but this did not reach statistical significance.

- Results suggest wider general use of real-time US guidance as an additional tool to improve PDT.

• Sponsorship/ conflict of interests?- Unrestricted research grant provided by Australian

Society for Ultrasound in Medicine (ASUM)- ‘ASUM had no involvement, direct or indirect, in the design, conduct, or reporting of this trial.’

• Journal? Authors?

• RECRUITMENT:

- Were study subjects representative of the target population?

- PROBABLY - Though 17 out of potential 72 patients were missed.

• RECRUITMENT- Was sample adequately powered?

- No pilot study for power calculation.

- Sample size calculated based on PRESUMED average degrees of displacement from midline (25 +/- 15 degrees from midline in landmark group; and 15+/- 10 degrees in US group)

- Used assumptions to estimate sample size of 50 required to detect 80% power with 0.05 CI.

• ALLOCATION:- Was the randomisation method unbiased?

- YES- According to previously published guidelines

- Were the groups matched as closely as possible at start of trial?

• MAINTENANCE:

- Was comparable treatment of the 2 groups maintained throughout the study?

- Was transparent information provided to show how and where subjects were ‘lost’ during the trial?

- Was transparent information provided to show how and where subjects were ‘lost’ during the trial?

•BLINDING:- Were outcomes measured with blinded subjects and

assessors?

- CARING team: not blinded- ANALYSIS team: blinded- Subjects/ relatives not blinded (consent had to be provided).

• OBJECTIVITY OF OUTCOME MEASUREMENT:- Were outcomes measured objectively?

PRIMARY OUTCOMES: - Accuracy of tracheal puncture (<30 degrees from midline)…..- Appropriate longitudinal puncture (between 1st- 4th

tracheal rings)….- Some subjectivity involved, but attempts to minimise this (consensus opinion of 2 assessors used).

SECONDARY OUTCOMES:- 1st pass tracheal puncture….YES- Measures of safety….some objective, some subjective.

• Could the effect have been due to chance?

• What measure was used and how large was the treatment effect?

• Bear in mind small numbers and powering methods of study

• Are the conclusions valid?- YES, but depends on how you interpret in light of power

calculation and small numbers.

• External validity and Generalisability of results to our population?

- YES: - Based in Sydney hospitals, with similar patient cohort.- PDT practices similar to local ICU’s.

• Use of real- time US can improve accuracy of tracheal puncture in PDT.

• Current study does not allow us to connect this with a clear improvement in complication rate / outcome (although intuitive to expect this).

• Hard not to use Ultrasound, given availability and familiarity with its use nowadays.