Randomised control trial
S D Crane, M W Elliott, P Gilligan, et alRandomised controlled comparison continuous positive airways pressure, bilevel non-invasive ventilation, and standard treatment in emergency department patients with acute cardiogenic pulmonary oedema
Emerg Med J 2004 21: 155-161
doi: 10.1136/emj.2003.005413
- Submitted by:Aasir Abuelnaga - Senior Emergency Doctor
- Institution:Central Manchester University Hospital
- Date submitted:21st February 2010
1
Objectives and hypotheses
1.1
Are the objectives of the study clearly stated?
Yes, to compare continuous positive airways pressure, bilevel non-invasive ventilation, and standard treatment in emergency department patients with acute cardiogenic pulmonary oedema.
2
Design
2.1
Is the study design suitable for the objectives
Yes, Prospective Randomised controlled Trial is the best way to test this question
2.2
Who / what was studied?
Between May 2000 and September 2001, Sixty patients presenting with acidotic (pH,7.35) acute, cardiogenic pulmonary oedema, were randomly assigned conventional oxygen therapy, CPAP (10 cm H2O), or bilevel ventilation (IPAP 15 cm H2O, EPAP 5 cm H2O) provided by a standard ventilator through a face mask. The main end points were treatment success at two hours and in-hospital mortality. Analyses were by intention to treat.
2.3
Was this the right sample to answer the objectives?
Yes, Adults who attended either of the emergency department resuscitation rooms of two university hospitals in Leeds with acute dyspnoea, and who had clinical evidence of CPO in the opinion of the treating doctor (for example, widespread pulmonary crepitations, diaphoresis) were eligible for enrolment. Inclusion criteria were: respiratory rate greater than 23 breaths per minute, chest radiological appearance consistent with pulmonary oedema, and arterial blood pH,7.35 (H+ ion concentration.46.7 nmol/l). Exclusion criteria were: hypotension (systolic blood pressure,90 mm Hg), temperature.38°C, patients requiring immediate thrombolysis for myocardial infarction, patients requiring dialysis for renal impairment, patients with impaired consciousness (only responding to pain or not responding at all), and patients with dementia
2.4
Is the study large enough to achieve its objectives? Have sample size estimates been performed?
No, not mentioned
2.5
Were all subjects accounted for?
Yes
2.6
Were all appropriate outcomes considered?
Yes
2.7
Has ethical approval been obtained if appropriate?
Yes, the research ethics committee of the Leeds Teaching Hospitals NHS Trust approved the study
2.8
Were the patients randomised between treatments?
Yes.
2.9
How was randomisation carried out?
The randomisation sequence was generated using random numbers produced by Microsoft Excel. Assignments were concealed in an opaque envelope, which was then further concealed within another.
2.10
Are the outcomes clinically relevant?
Yes
3
Measurement and observation
3.1
Is it clear what was measured, how it was measured and what the outcomes were?
Treatment success (defined as all of respiratory rate,23 bpm, oxygen saturation of.90%, and arterial blood pH.7.35 (that is, reversal of acidosis), at the end of the two hour study period) occurred in three (15%) patients in the control group, seven (35%) in the CPAP group, and nine (45%) in the bilevel group (p = 0.116). Fourteen (70%) of the control group patients survived to hospital discharge, compared with 20 (100%) in the CPAP group and 15 (75%) in the bilevel group
3.2
Are the measurements valid?
Yes
3.3
Are the measurements reliable?
Yes
3.4
Are the measurements reproducible?
Yes
3.5
Were the patients and the investigators blinded?
No, not really possible to do
4
Presentation of results
4.1
Are the basic data adequately described?
Yes
4.2
Were groups comparable at baseline?
Yes, table 2.
4.3
Are the results presented clearly, objectively and in sufficient detail to enable readers to make their own judgement?
Yes
4.4
Are the results internally consistent, i.e. do the numbers add up properly?
Most probably yes.
4.5
Were side effects reported?
Yes, Three patients in the CPAP group and two patients in the bilevel group could not tolerate assisted ventilation. One patient in each of the two intervention arms developed minor facial erythema as a result of the face mask. Two patients in
the control group and one in the CPAP group vomited during the study period.
the control group and one in the CPAP group vomited during the study period.
5
Analysis
5.1
Are the data suitable for analysis?
Yes, except Physiological measurements after intubation were excluded from the analysis
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?
Yes
6.2
Is the discussion biased?
Yes, authors seem in favour of CPAP, although their opinion is not justified by the findings
7
Interpretation
7.1
Are the authors' conclusions justified by the data?
No, as data in table 3 and 4 show that better improvement of vital signs & physiological parameters achieved by Bi-level, also the claimed better survival rate achieved by CPAP could be due to higher incidence of other co morbidities in the Bi-level group.
7.2
What level of evidence has this paper presented? (using CEBM levels)
2b.
7.3
Does this paper help me answer my problem?
No, it concluded result different from what was explained in the tables
8
Implementation
8.1
Can any necessary change be implemented in practice?
More use of non invasive ventilation
8.2
What aids to implementation exist?
More availability of non invasive ventilation devices in resuscitation room in emergency departments and training emergency doctors how to use those devices
8.3
What barriers to implementation exist?
Limited financial resources in some NHS hospitals