Success of Pediatric Anesthesiologists in Learning to Use Videolaryngoscopes: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Success of Pediatric Anesthesiologists in Learning to Use Videolaryngoscopes (NCT01215422), a registered phase not stated study. The primary outcome is Success in Learning to Use a Videolaryngoscope(VLS).

2. Clinical Question

3. Trial Design

This completed study, NCT01215422, is titled “Success of Pediatric Anesthesiologists in Learning to Use Videolaryngoscopes.” The registry lists the University of Alberta as sponsor, an enrollment of 646, a start of 2007-01, and primary completion in 2011-07. The study concerned tracheal intubation morbidity and the learning process for videolaryngoscopes in children.

The record describes children intubated with Glidescope and children intubated with DCI. Timed intubation is listed as a procedure. The primary outcome is expressed as a percentage of anesthesiologists, rather than as a child-level clinical outcome. The registry says that anesthesiologists were to perform 20 intubations with each videolaryngoscope. The first 1-10 were designated for practice, followed by assessment of success using later attempts.

This is not described as a randomized comparison, and allocation is not stated. The record therefore does not establish that the two arms can be interpreted as exchangeable treatment groups. Further details about assignment, masking, study setting, eligibility criteria beyond the primary analysis population, and any concurrent or sequential use of the devices are not reported in the registry record.

The registry lists six outcome measures and three analyses. Secondary outcomes include Cormack & Lehane Score, time to intubation analyzed by order of laryngoscopes used, time to intubation stratified by patient weight, mean years since completion of anesthesiology residency, and the number of intubation attempts to reach the “Best Obtainable Time to Intubation.” The outcome results and detailed analysis descriptions are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Before assignment: Patients with anticipated difficult airways were excluded.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Only anesthesiologists who completed minimum 18 intubations with either laryngoscope were analyzed for the primary outcome.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Success in Learning to Use a Videolaryngoscope(VLS), measured over Up to 5 minutes per intubation.

The primary endpoint is the percentage of anesthesiologists classified as achieving success in learning to use a videolaryngoscope. The registry defines rapid success as having no failed intubation attempts on attempts 11-20 and a median time to intubation no more than 50% longer than the operator’s baseline median time on attempts 11-15. Delayed success uses those same parameters on attempts 16-20 if they were not achieved on attempts 11-15. Operators who met neither definition were classified as having no success.

This endpoint combines a measure of procedural reliability, failed attempts, with a measure of speed, time to intubation. A combined classification can describe whether learning met both stated criteria, rather than treating speed alone as adequate performance. The listed timeframe is up to 5 minutes per intubation. The registry does not report the observed percentages for rapid, delayed, or no success, or how those categories were distributed between the laryngoscopes; these results are not reported in the registry record.

The primary analysis population was restricted to anesthesiologists who completed a minimum of 18 intubations with either laryngoscope. The record does not report how many operators qualified or how incomplete attempts were handled. Because the endpoint is operator-level, it should not be read as the percentage of children with a particular outcome.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a learning endpoint based on repeated intubations and a categorical success rule. It does not report the observed primary outcome, the detailed statistical analysis plan, or the numerical analyses for the listed secondary outcomes. General statistical explanations below clarify how such measures are usually interpreted; they are not claims about analyses performed in this study.

What does a percentage of operators describe?

A percentage summarizes the proportion of operators in an analysis population who satisfy a defined category. Here, the endpoint distinguishes rapid success, delayed success, and no success. For a percentage to be interpreted, its denominator and analysis population need to be clear. The registry specifies that the primary analysis included only anesthesiologists completing a minimum of 18 intubations with either laryngoscope, but the number analyzed is not reported in the registry record. Nor are category counts or percentages reported.

Operator-level outcomes should be kept distinct from patient-level outcomes. Multiple intubations may be associated with the same operator, so treating every procedure as though it were an independent operator-level observation could misrepresent uncertainty. General statistical methods can account for clustering when outcomes are analyzed at more than one level. The registry’s detailed approach to repeated procedures and operator clustering is not reported in the registry record.

Why does the success rule use both attempts and time?

The definition makes success depend on two features: failed attempts and median time to intubation. Combining criteria can make the endpoint more informative than either feature alone, but it also creates a threshold-based classification. Results near the time threshold may be classified differently from results that clearly meet it, even if their underlying performance is similar. The registry does not report the distribution of times or failed attempts, so the sensitivity of the classification to its thresholds cannot be assessed from the record.

A median describes the middle of an ordered set of observations and is less affected by an unusually long time than a mean. However, medians alone do not describe the full spread or shape of a time distribution. A confidence interval, when reported, conveys statistical uncertainty around an estimate under the assumptions of the analysis; it does not show the full range of individual experiences. No confidence intervals or distributions for the primary outcome are reported in the registry record.

How should time-to-intubation outcomes be understood?

Time to intubation is a duration measure. The registry lists analyses by order of laryngoscopes used and by patient weight, but does not give the corresponding estimates or specify the statistical models. General analysis of duration data may use means, medians, or models depending on the distribution and study design. If the analysis concerns time until an event, methods may also need to account for observations where the event is not observed within the available follow-up. The registry does not state that such methods were used in this trial.

Order of device use may be important in a learning study because experience can change performance over successive attempts. A comparison that ignores order could mix device differences with learning or sequence effects. Conversely, a stratified or adjusted analysis can address such features only if the relevant design and analysis details are known. The registry lists an outcome analyzed by order, but the analysis method and results are not reported in the registry record.

What does over-dispersion mean in general?

For count outcomes, a simple statistical model may assume that variability follows a specified relationship to the mean. Over-dispersion means the observed variability is greater than that assumption allows. If it is ignored, uncertainty can be understated and statistical tests can become too optimistic. Alternative models or robust uncertainty estimates may be appropriate in general. This is a general statistical point; the registry does not report whether over-dispersion was assessed or whether count models were used.

What do the planning assumptions mean?

The registry’s planning illustration is described as using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the target effect expressed as a stated fraction of the observed effect. General sample-size calculations estimate the participants per arm needed to detect an assumed effect under specified assumptions. They are planning illustrations, not observed power, and they are not evidence that the study was designed with those assumptions. The record does not report that these were the trial’s original design assumptions, nor does it provide the numerical effect or planning outputs in the registry record for this account.

Recalculated estimates, when based only on posted summary statistics, are simple unadjusted calculations and should not replace a sponsor’s own analysis. No such recalculated result or discrepancy is described in the registry record. The record’s detailed inferential methods, including model specifications, adjustments, handling of repeated observations, and uncertainty calculations, are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary outcome and several secondary outcomes, including airway view, intubation time under different classifications, operator experience, and attempts to reach the best obtainable time. When multiple outcomes or analyses are examined, the chance of at least one apparently notable result can increase. General approaches to multiplicity include designating a primary endpoint in advance, adjusting inference across tests, or treating secondary analyses as exploratory. The registry does not report a multiplicity strategy, a hierarchy among secondary outcomes, or which analyses were confirmatory; these details are not reported in the registry record.

The record identifies the primary analysis population as anesthesiologists who completed a minimum of 18 intubations with either laryngoscope. It does not state how many met that criterion, how missing attempts or incomplete operator records were handled, or whether the analysis followed an intention-to-treat principle. The way missing data were addressed is not reported in the registry record.

Enrollment of 646 does not indicate the size of the primary analysis population. The record does not provide a participant flow, reasons for non-completion, exclusions from particular outcomes, or denominators for the primary success categories. These omissions limit assessment of selection into the analyzed population and of whether incomplete participation could affect the findings.

The registry also does not describe the allocation process, which prevents assessment of baseline comparability or the role of confounding in the arm comparison. The detailed statistical analysis plan, including any pre-specified subgroup analyses or sensitivity analyses, is not reported in the registry record.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 1% reporting threshold.

Most frequent non-serious adverse event terms

The registry lists serious adverse events as zero in each of the recorded groups: Overall Anesthesiologists, Baseline Intubation Participants, KS Intubation Participants, and GS Intubaton Participants. The corresponding numbers at risk are 13, 249, 196, and 201, respectively, as listed in the record. These are group-specific entries; the record does not clarify whether groups overlap, so they should not be added or treated as independent populations.

The “other” adverse-event entries are 0 for Overall Anesthesiologists, 2 for Baseline Intubation Participants, 2 for KS Intubation Participants, and 4 for GS Intubaton Participants. The specific event terms and their clinical descriptions are not reported in the registry record. These figures should not be interpreted as a complete account of the nature, severity, timing, or relationship of events to a device.

Deaths are not reported in the registry record. The absence of a serious event entry in these listed groups is a description of the registry entries, not proof that no events occurred outside the recorded scope or that the devices are safe. The record does not provide comparative safety estimates or uncertainty around these counts.

12. What the Result Does, and Does Not, Mean

The registry record documents a study designed to assess how anesthesiologists learn to use videolaryngoscopes in children. Its primary endpoint is a defined operator-level classification based on failed attempts and median intubation time. The criteria distinguish rapid success, delayed success, and no success, and specify a minimum number of completed intubations for inclusion in the primary analysis.

The record does not report the primary outcome percentages, arm-specific results, uncertainty estimates, or detailed secondary outcome results. It therefore does not support a conclusion about the observed level of learning or about a difference between Glidescope and DCI. The result is not reported in the registry record.

Even if an outcome estimate were available, the endpoint would represent performance under the stated learning criteria, not every aspect of intubation quality or patient experience. It is not itself a measure of morbidity, and the registry does not provide results that connect the learning classification to clinical outcomes in children. The child-level and operator-level questions should not be conflated.

The study is not described as a randomized comparison, and allocation is not stated. Any contrast between the named arms could therefore be affected by design features or differences between groups that the record does not describe. A non-randomized arm comparison cannot automatically be read as a causal estimate of one device’s effect relative to another.

The enrollment figure and completion dates describe the registered study, but do not establish how many operators contributed to the primary analysis or how complete the outcome data were. Missingness, exclusions, and analysis methods are not reported in the registry record. The most defensible interpretation is therefore descriptive: the record defines a learning outcome and lists study arms and safety counts, while leaving the primary efficacy result and important analytical details unavailable.

13. Why This Trial Matters Statistically

This trial is statistically notable because its main question concerns learning over repeated procedures rather than a single procedure outcome. Performance can change with experience, so the order of attempts and the order of laryngoscope use are relevant to interpreting time and success. The registry explicitly lists time to intubation analyzed by order of laryngoscopes used and attempts to reach a best obtainable time, but does not report the results or methods for those analyses.

The primary endpoint also combines a reliability condition with a timing condition. This makes the learning classification clinically interpretable as a threshold-based rule, while making it important to examine the components as well as the overall category. Without component results, a single success percentage would not explain whether failed attempts, time, or both drove the classification. The record does not report those component summaries.

The analysis population is another important statistical feature. Eligibility for the primary analysis required a minimum of 18 completed intubations with either laryngoscope. Learning results among operators who complete that amount of practice may not describe operators with less complete exposure. The number meeting the criterion and the handling of incomplete data are not reported in the registry record.

Finally, the study’s named arms should not be mistaken for a randomized comparison. Allocation is not stated, and the registry does not establish comparability between groups. Statistical interpretation depends not only on the endpoint definition but also on the design, analysis population, and uncertainty around estimates. Here, those elements are incompletely described, and the primary result is not reported in the registry record.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

A central limitation is that the registry record does not report the primary outcome result. It provides the success criteria but no percentage of anesthesiologists in any success category and no comparison by laryngoscope. No confidence intervals or inferential results for the primary endpoint are reported in the registry record.

The design details are limited. The study is not described as randomized, and allocation is not stated. The record does not explain whether each anesthesiologist used both devices, how device order was determined, or whether learning effects were incorporated in the primary analysis. Although secondary outcomes include analysis by order of laryngoscope use, their methods and results are not reported.

The primary analysis population excludes operators who did not complete the minimum of 18 intubations with either laryngoscope. The record does not report how many operators were analyzed, why others may not have qualified, or how missing attempts were treated. This makes it difficult to evaluate selection into the analysis population or the completeness of the data.

The endpoint depends on thresholds for failed attempts and time. The registry does not report component distributions, sensitivity analyses, or how close observations were to the threshold. The extent to which classification depends on the chosen cutoffs cannot be assessed.

Further limitations include the absence of detailed methods for the listed secondary analyses, multiplicity handling, sample-size justification for the original study, and participant flow. These items are not reported in the registry record. The safety entries also lack event descriptions and death information. Together, these gaps constrain both comparison of the devices and assessment of the precision and completeness of the reported findings.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Success of Pediatric Anesthesiologists in Learning to Use Videolaryngoscopes — NCT01215422.
• Registry record last updated 2012-10-08; status last verified 2012-10.
• Results first posted 2012-10-08.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

NCT01215422 is a completed University of Alberta study titled “Success of Pediatric Anesthesiologists in Learning to Use Videolaryngoscopes.” The registry lists enrollment of 646, a study start of 2007-01, and primary completion in 2011-07. It describes children intubated with Glidescope and children intubated with DCI, and lists timed intubation as a procedure.

The primary outcome is the percentage of anesthesiologists achieving rapid or delayed success under criteria combining failed attempts and median time. The primary analysis population required a minimum of 18 intubations with either laryngoscope. The primary outcome result, detailed statistical plan, and secondary outcome results are not reported in the registry record.

The record lists zero serious adverse events in each recorded group, alongside “other” adverse-event counts, but does not provide event descriptions. Allocation is not stated, and the study is not described as a randomized comparison.