Therapy
Antibiotic prophylaxis of early onset pneumonia in critically ill comatose patients. A randomized study.
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This review may be
edited
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Summary
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Posted By: |
Stuart Green |
E-Mail: |
stuart_green@health.qld.gov.au
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Posted Date: |
25/5/2005 |
Title: |
Antibiotic prophylaxis of early onset pneumonia in critically ill comatose patients. A randomized study. |
Authors: |
Acquarolo A, Urli T, Perone G, Giannotti C, Candiani A, Latronico N. |
Reference: |
Intensive Care Med. 2005 Apr;31(4):510-6. Epub 2005 Mar 8. |
Link: |
Click here for a direct link to the paper. A password may be required for access to fulltext.
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Abstract: |
OBJECTIVE: To evaluate if a 3-day ampicillin-sulbactam prophylaxis can reduce the occurrence of early-onset pneumonia (EOP) in comatose mechanically-ventilated patients. DESIGN: This was a single-centre, prospective, randomised, open study. SETTING: A 10-bed general-neurological ICU in a 2,000-bed university hospital. PATIENTS AND PARTICIPANTS: Comatose mechanically-ventilated patients with traumatic, surgical or medical brain injury. INTERVENTIONS: Patients were randomized to either ampicillin-sulbactam prophylaxis (3 g every 6 h for 3 days) plus standard treatment or standard treatment alone. MEASUREMENTS AND RESULTS: Main outcome was the occurrence of EOP. Secondary outcome measures were occurrence of late-onset pneumonia, percentage of non-pulmonary infections and of emerging multiresistant bacteria, duration of mechanical ventilation and of ICU stay and ICU mortality. Interim analysis at 1 year demonstrated a statistically significant reduction of EOP in the ampicillin-sulbactam group, and the study was interrupted. Overall, 39.5% of the patients developed EOP, 57.9% in the standard treatment group and 21.0% in the ampicillin-sulbactam group (chi-square 5.3971; P =0.022). Relative risk reduction of EOP in patients receiving ampicillin-sulbactam prophylaxis was 64%; the number of patients to be treated to avoid one episode of EOP was three. No differences in other outcome parameters were found; however, the small sample size precluded a definite analysis. CONCLUSIONS: Antibiotic prophylaxis with ampicillin-sulbactam significantly reduced the occurrence of EOP in critically ill comatose mechanically ventilated patients. This result should encourage a large multicenter trial to demonstrate whether ampicillin-sulbactam prophylaxis reduces patient mortality, and whether antibiotic resistance is increased in patients receiving prophylaxis.
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Are the Results Valid?
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1.
Was the assignment of patients to treatments randomized? ( Was allocation concealment maintained?) |
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Yes, allocation concealment was maintained by the use of sealed opaque envelopes, which were kept in a locker, whose key was available to the attending intensivist. |
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2.
Were all patients who entered the trial properly accounted for and attributed at its conclusion? |
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2a.
Was followup complete? |
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No (see fig 1). 150 patients were screened, 108 excluded (reasons given) and 42 patients were randomised.
Four patients were randomised into the trial but 'excluded' from the intention-to-treat analysis due to 'protocol violations' (3 ventilated less than 24 hours, 1 had admission diagnosis of pneumonia. This is approximately 10% loss to follow-up. |
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2b.
Were patients analyzed in the groups to which they were randomized? |
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38 patients were analysed in the groups they were assigned to, the "drop outs" were not analysed in an intention to treat. |
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3.
Were patients, health workers, and study personnel blind to treatment? |
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NO.
Patients in the standard treatment group
did not receive a placebo.
Treating physicians and paramedics were not blinded to treatment allocation; the outcome adjudicators (TU, CG) and the data analyst (NL) were. |
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4.
Were the groups similar at the start of the trial? |
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Yes, table 1 appears to be in balance. |
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5.
Aside from the experimental intervention, were the groups treated equally? |
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Not explictly stated. As there was not blinding to the treatment this cannot be guarenteed. |
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What are the Results?
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1.
How large was the treatment effect? |
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This study was stopped early due to meeting the pre-specified Pocock stopping threshold at the 1 yr interim analysis (p = 0.024).
The authors report that EOP was reduced from 57.9% to 21.0% (p = 0.022).
The p-value reported above (0.022) is obtained from an uncorrected chi-square test. With continutity correction, which may be more appropriate in small samples, the p-value is 0.046. [calculated by Gord]
The p-value obtained from Fisher's Exact test, which is definitely more appropriate when any cell in the 2x2 table is less than 5, is 0.045. [calculated by Gord using SAS]
It is likely that the early stopping of this trial was inappropriate and subject to a Type I error. - Gord
For an excellent review of stopping rules and type I errors, click here. |
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2.
How precise was the estimate of the treatment effect? |
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As calculated in the paper, the 95% CIs are:
RRR=0.660 (0.127-0.875)95% CI
ARR=0.368 (0.097-0.639)
NNT = 2.7 (2-10) |
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Will the Results Help Me In Caring For My Patients?
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1.
Can the results be applied to my patient care? |
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Of the 119 patients admitted to my hospital with similar Dx, 46 were ventilated >72 hours. 22 patients have positive trachial aspirates out of 37 available. Organism grown were; staph-9, H influ-10 Pneumococcus-3 others 6. Due to the small numbers in the trial, and dubious outcomes,
more study is needed |
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2.
Were all clinically important outcomes considered? |
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Only EOP ( early onset pneumonia) was considered. Mortality outcomes needed plus others and financial secondary outcomes. |
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3.
Are the likely treatment benefits worth the potential harms and costs? |
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Connot tell. |
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What other people had to say about:
Antibiotic prophylaxis of early onset pneumonia in critically ill comatose patients. A randomized study.
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