Cohort
levitan RMLimitations of difficult airway prediction in patients intubated in the emergency department.
Ann Emerg Med
2004;44:307-313
- Submitted by:Simon Carley - Consultant in Emergency Medicine
- Institution:Manchester Royal Infirmary
- Date submitted:29th April 2005
1
Objectives and hypotheses
1.1
Are the objectives of the study clearly stated?
Yes. This is a retrospective observational cohort that seeks to determine if tests of difficult airway prediction are achievable in the ED. They specifically looked at Mallampati, thyromental distance and neck mobility.
2
Design
2.1
Is the study design suitable for the objectives?
Yes, and no. Obviously an observational cohort is the right model. However, the retrospective way it has been done does raise some concerns.
2.2
Who / what was studied?
Patients attending a US trauma centre (50,0000 per annum). Data on intubations was examined RETRospectively to determine if the patients could perform the tests.
2.3
Was a control group used if appropriate?
No needed
2.4
Were outcomes defined at the start of the study?
Yes.
Mallampati was determined as ability to comply with the test from the airway electronic record. GCS was used as a proxy
Thyromental was again recorded in the same way. GCS was used as a proxy.
Neck immobilisation was taken from records.
Mallampati was determined as ability to comply with the test from the airway electronic record. GCS was used as a proxy
Thyromental was again recorded in the same way. GCS was used as a proxy.
Neck immobilisation was taken from records.
2.5
Was this the right sample to answer the objectives?
Yes. Ed patients in an ED
2.6
Is the study large enough to achieve its objectives? Have sample size estimates been performed?
No sample size done but a pretty large sample. Enough to answer the question it would seem.
2.7
Were all subjects accounted for?
yes.
2.8
Were all appropriate outcomes considered?
No. Actual difficulty in intubation would have been useful to know.
2.9
Has ethical approval been obtained if appropriate?
NA
3
Measurement and observation
3.1
Is it clear what was measured, how it was measured and what the outcomes were?
Yes. retrospective case note review. This has problems as it relies on documentation and in this case proxy markers for ability to cooperate (they used GCS (M) of more than 6 as a marker of ability to perform).
3.2
Was the assessment of outcomes blinded?
No
3.3
Was follow up sufficiently long and complete?
Yes
3.4
Are the measurements valid?
Not really for reasons given above
3.5
Are the measurements reliable?
Yes, but what about the recording
3.6
Are the measurements reproducible?
Yes
4
Presentation of results
4.1
Are the basic data adequately described?
Yes. There is not that much that really needs to be known beyond basic epidemiological data.
4.2
Are the results presented clearly, objectively and in sufficient detail to enable readers to make their own judgement?
Yes
4.3
How large are the effects within a specified time?
They have found that only 32% of patient were likely to be able to have the tests done.
4.4
Are the results internally consistent, i.e. do the numbers add up properly?
Yes
5
Analysis
5.1
Are the data suitable for analysis?
Yes. percentages and confidence intervals.
5.2
Are the methods appropriate to the data?
Yes
5.3
Are any statistics correctly performed and interpreted?
Yes
6
Discussion
6.1
Are the results discussed in relation to existing knowledge on the subject and study objectives?
No seem to be appropriate and refelct the data
6.2
Is the discussion biased?
no
7
Interpretation
7.1
Are the author's conclusions justified by the data?
probably though the retrospective nature means it is difficult when considering the ability to follow commands as a proxy marker for compliance wit hairway assessment tests.
7.2
What level of evidence has this paper presented? (using CEBM levels)
Not sure
7.3
Does this paper help me to answer my problem?
No, but it confirms my initial thoughts.
8
Implementation
8.1
Can any necessary change be implemented in practice?
Consider the LEMON law
8.2
What aids to implementation exist?
8.3
What barriers to implementation exist?
No
8.4
Are the study patients similar to your own?
Yes
8.5
Does the paper give any conclusions that will affect what you will offer or tell your patient?
No