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Effect of learning during an anaesthesiological multicentre trial
Author(s) -
Honkavaara P.,
Paloheimo M.
Publication year - 1998
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/j.1399-6576.1998.tb05278.x
Subject(s) - medicine , propofol , anesthesia , post hoc analysis , dosing , clinical trial , clinical judgement , emergency medicine
Background: After the completion of a multicentre study, it was disputed whether becoming acquainted with a novel drug would affect dosing, and how many consecutive patients would be sufficient for this phenomenon. Methods: A post hoc analysis of the data on 408 patients from a multicentre study on propofol was performed to reveal a possible learning effect. For study purposes, the patients were given consecutive anaesthetic serial numbers per anaesthesiologist. Patients eligible for the study with serial numbers 3–8 (113) were included in the initial group, and numbers 12–17 (89) in the end group. Results: The patients in the end group opened their eyes (4.1 vs. 5.5 min, P <0.05), gave their date of birth (4.5 vs. 6.3 min, P <0.005) and walked sooner (27.1 vs. 49.8 min, P <0.05) than the patients in the initial group. They received a higher dose of propofol at induction (2.37 vs. 2.26 mg kg ‐1 , P <0.05) and the last additional dose of propofol earlier (3.3 vs. 2.7 min, P <0.05). Conclusion: This study shows that the learning effect can influence the results in a multicentre study. Learning contamination may occur if a novel drug is dosed by clinical judgement, and if the allocation of patients into groups is markedly uneven during the different stages of the study.