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Early tracheostomy 5

Citation: Dunham CM, LaMonica C. Prolonged tracheal intubation in the trauma patient. Journal of Trauma – Injury, Infection and Critical Care. 1984; 24: 120-124.

Lead author's name and fax: C Michael Dunham, Maryland Institute for Emergency Medical Services Systems, 22 South Greene Street, Baltimore, MD 21201.

Three-part Clinical Question: Does early compared to late tracheostomy in trauma patients alter the incidence of respiratory sepsis and of major complications of an artificial airway?
 

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

The Study: Non-blinded pseudo-randomised controlled trial without intention-to-treat.
 

The Study Patients: These were trauma patients who required ventilation. They were assessed at 48-72 hours, and pseudo-randomised if it were considered that they needed a further 48 hours of artificial ventilation. Entry into the study appears to have been subjective. Patients who had been extubated and then re-intubated were excluded. Only patients who were ventilated for more than 7 days were considered in the outcome analyses. The tracheostomy was obtained by an open surgical technique. Ventilation and weaning protocols were not discussed. Sedation was not discussed. Respiratory sepsis included peri-stomal infection, lung abscess and tracheitis as well as pneumonia. Pneumonia was not defined. (The meta-analysis took the whole group of respiratory infection to be just pneumonia and this may not be appropriate). Diagnosis of pneumonia was by the infectious disease service, and therefore may have been independent of the investigators: this is the only study of the five to do this.

Control group (N = 40; 40 analysed): These patients proceeded to tracheostomy on day 14, if still needed.
 

Experimental group (N = 34; 34 analysed): These patients underwent tracheostomy at day 3-4.

The Evidence: (Control is the late tracheostomy group).

Comments and EBM questions: 

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

      No. The main aim of this study was to look at the complication rates between early and late open surgical tracheostomy. These complications were laryngeal pathology, as identified by endoscopy and respiratory infection (this is not the same as pneumonia). Definitions of each were not given. There was no demonstration that the patient groups were similar. There is a potential source of bias in that patients who were not ventilated for more than 7 days were excluded from the study (attrition bias). There is no mention made of patients in the late group who did not subsequently proceed to tracheostomy (if any); implying lack of intention to treat. Only 65% of patients had laryngoscopy after extubation, and reasons for loss to follow up are not given (potential outcome bias). Patients were followed up to assess voice change, although results are not presented. In all, the study appears to be haphazard in its conduct and presentation.

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

      No. Statistical tests were straightforward. There was pseudo-randomisation by hospital number. There does not appear to have been a power calculation performed to account for the patient numbers, so the lack of a difference in outcome may have been a type II error.  Analysis was not on an intention to treat basis.

3)   Are conclusions valid in light of the results?

No. There are numerous potential problems with this study. It is not clear that the patients in the two groups were similar. Pseudo-randomisation, attrition and outcome biases could result in two very different samples. Superficially, the conclusion that there is no difference between early and late tracheostomy in terms of major laryngeal pathology requiring intervention seems reasonable (6 of 34 and 5 of 40 patients). They further analysed sub-groups and suggested that this incidence was highest in patients with rigid posture head injuries. It is not clear that the sub-groups were identified at the start of the study.

4)   Did results get omitted, and why?

Yes. Patients who needed less than seven days of ventilation were omitted. It is unclear if all patients randomised to late tracheostomy proceeded to it. Patients who had self-extubated or had been purposefully extubated were excluded, and it is unclear how many patients this covered.

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.

7)   Is the study relevant to my clinical practice?

Probably Not. This study focuses on complications of surgical technique tracheostomy. If you use open surgical technique then the timing may not affect the major complication rate.

8)   What level of evidence does this study represent? 1^- (RCT with significant risk of bias)

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

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. The question addressed is quite different from the other papers in the meta-analysis and it probably should not have been included.

11) Should I change my practice because of these results?No.

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

Only if you use open surgical technique.

 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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