Anesthesia Awareness and the Bispectral Index
2008 · paper · Clinical trials
A randomized trial of 2000 patients at high risk for awareness during anesthesia, comparing bispectral index monitoring with end-tidal anesthetic gas monitoring. Definite awareness occurred in two patients per group, so the earlier benefit of BIS was not reproduced.
2 findings
Substance "1754 patients (90.4%) completed all three interviews, 133 patients (6.9%) completed only two interviews, and 18 patients (0.9%) completed only one interview" sums to 1905, not the 1941 who "completed the study".
- p. 4 Results, first paragraph
1754 patients (90.4%) completed all three inter-views, 133 patients (6.9%) completed only two in-terviews, and 18 patients (0.9%) completed only one interview
- p. 4 Results, first paragraph
1941 completed the study (Fig. 1)
Only the authors can say what is right here.
Judge's note: Checked p4 (crop and text) and the Fig. 1 flow, which shows 967+974=1941 assessed for awareness. Every percentage uses 1941 as its denominator, yet the three categories add up to only 1905 (98.2%). Nothing in the paper describes a group with zero interviews or any other set that would hold the remaining 36 patients. The count for one category (e.g. 54 = 2.8% for 'only one') may be wrong, but only the authors can say which.
Second check: another model agreed
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Wording Text names only neurologic disease (P=0.008) as differing and says "The groups were similar with respect to other baseline characteristics," but Table 1 shows moderate exercise tolerance 486 (50.3%) vs 541 (55.5%), P=0.02.
- p. 8 Results, first paragraph
The groups were similar with respect to other baseline characteristics.
- p. 5 Table 1, minor inclusion criteria
Moderate exercise tolerance
Judge's note: Table 1 on p5 shows the moderate-exercise-tolerance row with P=0.02. The Methods set the significance threshold at P<0.05. The text on p8 singles out only neurologic disease and calls all other characteristics similar. That understates what the table shows.
Second check: another model agreed
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2 minor (typos and the like; most checked by the judge only)
Wording Abstract: "For all patients, the mean (±SD) time-averaged ETAG concentration was 0.81±0.25 MAC in the BIS group and 0.82±0.23 MAC..." — these are the maintenance-phase figures (p.8), which the Methods (p.4) derive only from traces of patients "who did not report anesthesia awareness".
- p. 1 Abstract, Results
For all patients, the mean (±SD) time-averaged ETAG concentration was 0.81±0.25 MAC
- p. 8 Results, last paragraph
time-averaged ETAG concentration during the maintenance phase was 0.81±0.25 MAC
- p. 4 Methods, maintenance period definition
systematically reviewed the BIS and ETAG traces from each patient who did not report anesthesia awareness
Only the authors can say what is right here.
Judge's note: Looked at the abstract crop (p1), the Results on p8 (identical values, P=0.10 and CI −0.04 to 0.01, labelled 'during the maintenance phase') and the Methods on p4, which say the maintenance period was found by reviewing the traces of each patient who did not report awareness, with periods of missing data excluded. The ETAG-based count on p8 uses 1717 patients. 'For all patients' may just mean both groups together. Even so, it leaves out both the maintenance-phase restriction and the exclusion of patients who reported awareness, and it does not match the analysed set as the Methods describe it. Only the authors can say which population is meant.
Second check: another model agreed
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Typo Table 2, Patient 14: "Anterior cervical diskectomy and fusion of L5 to L6 and L6 to L7" gives lumbar levels for a cervical procedure.
- p. 7 Table 2, Patient 14, Surgery column
Anterior cervical disk-ectomy and fusion of L5 to L6 and L6 to L7
Only the authors can say what is right here.
Judge's note: Rests on outside knowledge: an anterior cervical diskectomy is done at cervical levels (C), and a normal spine has no L6 or L7. The upright image of p7 shows the text exactly as quoted. The patient's own report in the same row ('My neck got stiff') also points to a cervical operation, so 'C5 to C6 and C6 to C7' was probably meant.
Second check: none (judge only)