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Early tracheostomy 3

Citation: Saffle JR, Morris SE, Edelman L. Early tracheostomy does not improve outcome in burn patients. Journal of Burn Care and Rehabilitation. 2002; 23: 431-438.
Lead author: JR Saffle. Dept. Surgery, University of Utah Health Centre, 50 North Medical Drive, Salt Lake City, Utah 84132.

Three-part Clinical Question: Does early compared to delayed tracheostomy in burns patients, who are projected to require prolonged ventilation, alter the incidence of death, pneumonia, ventilator days and hospital stay.

Search Terms: This is one of the five studies that contributed to the meta-analysis of Griffiths et al.

The Study: Non-blinded concealed randomised controlled trial with intention-to-treat.
 

The Study Patients: These were burns patients who were ventilated. There was an objective projection of the need for prolonged ventilation. This was based around a previously published formula that had been developed in the same unit. This weighted the patients age; area of full thickness burn; the PaO₂/FiO₂ ratio and the presence of inhalational injury (as assessed by bronchoscopy). Patients were assessed at day 2; those calculated to be at high risk of prolonged ventilation were randomised to either early or delayed tracheostomy. Other management was discussed. There were ventilation and weaning protocols, but sedation was not discussed. The diagnosis of pneumonia was on the CDC criteria. It was not stated if its diagnosis was independent, and therefore may be prone to detection bias. Tracheostomy was obtained mostly with an open surgical technique.

Control group (N = 23; 23 analysed): Patients randomised to the control arm underwent standard care, and if still requiring ventilatory support, proceeded to tracheostomy at around day 14.

Experimental group (N = 21; 21 analysed): Experimental patients underwent tracheostomy the next day, around day 4.

The Evidence: (Control is the late tracheostomy group)

Comments and EBM questions: 

1)      Do the methods allow accurate testing of the hypothesis?

Broadly, yes. The study recruitment took over 5 years to find 44 patients; other changes in the delivery of critical care may have occurred in that time. In this time 64 patients were eligible for the study, and reasons for not recruiting the other 20 were given. Ventilatory and weaning parameters were discussed; sedation of patients was not. There was a higher percentage of full thickness burns and a high probability of prolonged ventilation in the early tracheostomy group. Despite the predictive formula, 7 of the 23 patients randomised to the delayed tracheostomy group were successfully extubated by day 14 (this compares to 1 from the early tracheostomy group). A number of patients not randomised to the study in fact required prolonged ventilatory support. Perhaps patients here also have a need for airway protection from facial swelling and this was not really discussed. The authors debated how useful, or not, the CDC criteria for the diagnosis of pneumonia is in this patient group. Given that 85% of patients had an inhalational injury, this is quite pertinent. This definition applied to both arms of the study. The very high incidence of pneumonia is of relevance to the meta-analysis as it gives this study the highest weighting, despite having the smallest number of patients.

2)  Do the statistical tests correctly test the results to allow differentiation of statistically significant results?

      Yes. Statistical tests were straightforward. There was genuine randomisation. There does not appear to have been a power calculation performed to account for the patient numbers. Analysis was on an intention to treat basis. Students t-test was used for time related outcomes without demonstration of normality.

3)   Are conclusions valid in light of the results?

To an extent. It may be valid here to conclude that early vs late tracheostomy does not make much difference to these outcomes in these patients. They commented that their results did not demonstrate a disadvantage to early tracheostomy either. The comment was made that a tracheostomy may lead to a more relaxed approach to weaning due to enhanced patient comfort; this is speculative. They proposed that early tracheostomy may decrease the chance of early weaning and should be postponed until day 7; their data does not support this and this too is speculative. They commented that it is appropriate to perform tracheostomy early for reasons such as airway or facial swelling; this is also speculative.

4)   Did results get omitted, and why?

No.

5)   Did they suggest areas of further research?

No. The discussion section focused on a limited review of the topic.

6)   Did they make any recommendations based on the results and were they appropriate?

Not specifically. Some of these recommendations were speculative, as discussed in section 3.

7)   Is the study relevant to my clinical practice?

Largely. If you look after patients with severe burns. Otherwise these patients do not represent typical ICU patients. Timing of a tracheostomy does not affect the outcomes measured.

8)   What level of evidence does this study represent? 1⁺ (RCT with a low risk of bias.)

9) What grade of recommendation can I make on this result alone? B

10) What grade of recommendation can I make when this study is considered along with other available evidence?

This is the only prospective randomised study of its type in burns patients; there are mixed results from other patient groups and these have been subject to meta-analysis.

11) Should I change my practice because of these results?

It depends. This paper does not really provide convincing evidence to perform early tracheostomy in patients with severe burns. The potential utility of prolonged trans-laryngeal intubation was not addressed.

12) Should I audit my current practice because of these results?

Yes. It may be reasonable to audit the timing and outcome of patients with severe burns who proceed to tracheostomy.

 Appraised by: Richard Price; SpR, Dept. Anaesthetics, Gartnavel Hospital, Dumbarton Road, Glasgow, G12 0YN.  Monday, 27 March 2006
Email: rjp@doctors.org.uk

Kill or Update By: March 2011.

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