High Velocity Nasal Insufflation (Hi-VNI) Use in Upper Airway Surgery: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for High Velocity Nasal Insufflation (Hi-VNI) Use in Upper Airway Surgery (NCT05090852), a na na study. The primary outcome is Surgical Case Completion Rate Using HVNI With or Without Converting to Alternative Mode of Oxygenation.

2. Clinical Question

The study aimed to assess the use of Hi-VNI in upper airway surgery from anesthesiologists’ and surgeons’ perspectives, and to describe suitable patients, pathologies, and clinical scenarios. Those aims frame the clinical question, but the registry record does not report results for these perspectives or describe findings about patient selection.

The outcome description states that a participant with SpO2 < 93 or TcCO2 > 65 during the procedure was converted to another means of oxygenation. These thresholds describe the stated procedure for conversion; they do not, by themselves, establish whether the surgery was completed or whether Hi-VNI alone was sufficient. The primary outcome results needed to answer those questions are not reported in the registry record.

3. Trial Design

This was a completed, single-group study of Hi-VNI use during upper airway surgery. The registry lists the allocation as not applicable and masking as none. Its study model is single-group, and the intervention is a device used as a primary or adjunct oxygenation technique. The registry lists an enrollment of 31 and the condition as upper airway surgery.

The study began on 2020-10-22 and had a primary completion date of 2021-09-30. Its status is completed. The registry lists the phase as not applicable. These details describe the study record, but do not establish how participants were selected, how many sites participated, or whether enrollment and outcome assessment followed a particular schedule; those details are not reported in the registry record.

The registry’s outcome description says participants received Hi-VNI at a flow rate of 40 L/min and FiO2 of 100%. If SpO2 fell below 93 or TcCO2 rose above 65 during the procedure, the description says they were converted to an alternative means of oxygenation, including mask ventilation or endotracheal intubation. The primary outcome is described as surgical case completion with or without conversion. No separate randomized comparator is identified, and the record cautions against treating the listed groups as a like-for-like control comparison.

Without random allocation to different oxygenation strategies, this design can describe experience with the study’s approach but cannot, by itself, establish a causal contrast between Hi-VNI and an alternative. Conversion is a response within the treatment approach as described, not an independently assigned comparison strategy. The registry record does not report a detailed protocol, a sample-size justification, or a statistical analysis plan. Although the study is marked completed, the primary outcome results and an analysis of them 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.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Adult patients undergoing upper airway surgery who received HVNI, We compared patients who successfully completed their anesthesia for the surgical case with HVNI vs patients who had to be intubated.

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.

Population: Patients undergoing anesthesia for airway laryngeal surgery

6. Primary Endpoint

The registry lists the primary outcome as Surgical Case Completion Rate Using HVNI With or Without Converting to Alternative Mode of Oxygenation, measured over 1 day.

The primary endpoint is titled “Surgical Case Completion Rate Using HVNI With or Without Converting to Alternative Mode of Oxygenation.” It is recorded as a count of participants, with a timeframe of 1 day. The description says the study assessed whether the surgical procedure could be completed using only Hi-VNI, and then defines the primary outcome more broadly as case completion with or without conversion to another oxygenation method.

This endpoint is intended to capture procedural completion in the context of the oxygenation strategy, including whether an alternative method was needed. Completion alone and completion using Hi-VNI without conversion are not interchangeable outcomes: a procedure may be completed after a change in oxygenation method. Reporting these categories separately would help readers understand both completion and the role of conversion. The registry record does not report the counts in either category, so the distinction cannot be quantified from the record.

The endpoint is clinically relevant to the study’s stated aims because it concerns the ability to carry out surgery while using Hi-VNI as a primary or adjunct technique. Its interpretation depends on a clear definition of success and on knowing how converted cases are classified. The wording leaves some ambiguity between the “only Hi-VNI” assessment and the broader completion measure. The registry record does not report further endpoint definitions, adjudication procedures, or a numerical primary outcome result.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical interpretation starts with the question the design can answer. This study is recorded as single-group, with allocation not applicable and no masking. It describes Hi-VNI use during upper airway surgery rather than randomized assignment between Hi-VNI and a control strategy. The primary endpoint is a participant count related to surgical case completion, with the stated timeframe of 1 day. Because the registry record does not post the endpoint counts or an analysis, there is no reported estimate to interpret statistically.

What does a count endpoint tell readers?

A count records how many participants meet a defined outcome. To interpret a count, readers also need a clear outcome definition and the number of participants whose outcomes were assessed. A rate or proportion ordinarily relates the number meeting the outcome to an appropriate denominator. The registry gives an enrollment of 31, but does not state the primary-outcome analysis denominator or report completion counts. It would therefore be inappropriate to derive a rate from enrollment or to treat all enrolled participants as having an observed outcome.

The endpoint wording also matters. “Completion with or without converting” can include more than completion using Hi-VNI alone. If these are clinically distinct categories, separate counts would clarify whether completion required a change in oxygenation method. The description mentions assessing completion using only Hi-VNI and also defines the primary outcome as completion with or without conversion. The registry record does not report how this wording was operationalized in the final analysis. Statistical methods cannot resolve that ambiguity without a fuller endpoint definition and the outcome data.

Why does the design limit comparative interpretation?

In a randomized comparison, assignment is used to make treatment groups comparable, on average, with respect to measured and unmeasured characteristics. This study is not recorded as randomized and has a single-group model. Participants who were converted to another oxygenation method were not described as a separately assigned control group. A comparison between participants who did and did not require conversion would therefore be an observational comparison within the study experience, not an estimate of the effect of random assignment to alternative strategies.

That distinction matters because conversion may be related to the participant’s condition or the course of surgery. A difference in outcome between participants who were converted and those who were not could reflect those circumstances, the oxygenation strategy, or both. Statistical adjustment can address some measured differences in suitable data, but cannot automatically remove confounding or replace randomization. The registry record does not report an adjusted analysis or the information needed to assess such an analysis.

How should uncertainty be assessed?

A confidence interval is a general statistical tool that expresses uncertainty around an estimate under the model and assumptions used. A narrow interval indicates greater precision than a wide interval, while an interval that spans a broad range of plausible values leaves more uncertainty. An interval does not correct a poorly defined endpoint, missing outcomes, or a design that cannot support the desired causal comparison. The registry record does not report an endpoint estimate or confidence interval, so the precision of the primary outcome cannot be evaluated.

For event counts, the amount of information depends on the number of observed events as well as the number assessed. When events are uncommon, estimates can be imprecise even when the study has enrolled participants. Here, the primary outcome is not reported, so its event or completion count is unknown. The serious adverse event record lists zero events, but that separate safety count does not provide precision for the primary endpoint.

What do the planning illustrations represent?

Any sample-size illustrations associated with the record are planning calculations, not observed trial outcomes. The stated illustration assumptions use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. The record also specifies that non-time-to-event illustrations are expressed as participants per arm, while time-to-event illustrations express total events. These are generic planning conventions as described for the illustrations, not a description of the actual single-group study design.

A planning calculation asks how much information a hypothetical future study might need under chosen assumptions. Its output depends on the assumed effect and analysis model. Such a calculation is not “observed power,” and it does not show that the completed study was adequately powered. The record does not report the study’s own sample-size justification, and the primary outcome effect needed to evaluate a planning illustration is not reported in the registry record. The illustration’s two-arm assumptions should not be mistaken for evidence that this study enrolled randomized arms.

Why can over-dispersion matter in general?

For count data, a statistical model may assume a particular relationship between the average count and its variability. Over-dispersion means the observed variation is greater than the model expects. If that feature is ignored, uncertainty can be understated and statistical tests can be misleading. Whether over-dispersion is relevant depends on the outcome structure and analysis model. The registry record does not report a count model, a dispersion assessment, or an analysis plan, so it is not possible to say whether this issue arose in the study.

More broadly, an analysis plan would clarify which outcomes and populations were analyzed, how missing data were handled, and what statistical methods were used. Those details are not reported in the registry record. The absence of a posted analysis means readers should distinguish the study’s stated aims and procedures from a statistical result: the record gives the former, but does not provide a numerical primary-outcome estimate or its uncertainty.

10. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when an analysis examines multiple outcomes, comparisons, time points, or subgroups. The more questions tested, the greater the chance that at least one result appears noteworthy by chance if no adjustment or prespecified hierarchy is used. The registry lists one outcome measure and no analyses. It does not report a multiplicity strategy, a hierarchy of endpoints, or whether additional analyses were planned or conducted. The number of listed outcome measures alone does not establish what analyses were performed.

The primary outcome description includes related but distinct ideas: completing surgery using only Hi-VNI and completing surgery with or without conversion to another oxygenation method. The record does not report whether these were analyzed as separate outcomes or how the final endpoint was defined. That uncertainty concerns outcome definition and reporting, as well as any potential multiplicity.

Missing-data handling is also not reported in the registry record. There is no stated count of participants with an assessed primary outcome, no account of unavailable outcomes, and no description of any method for addressing missingness. Without those details, readers cannot tell whether the enrolled population and the population contributing to an endpoint analysis were the same, or assess how missing outcomes might affect interpretation.

The record does not report an analysis population definition, such as criteria for inclusion in a particular outcome analysis. Enrollment is listed as 31, but that figure should not be treated as the primary-endpoint denominator. The registry records no analyses, so there is no reported primary analysis population or sensitivity analysis to review. The protocol, statistical analysis plan, interim analyses, and sample-size justification are not reported in the registry record.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry lists a group labelled “Patients With HVNI and Patients With Intubation,” with 31 at risk, zero serious adverse events, zero other adverse events in the displayed serious-event fields, and zero deaths. The group label does not provide a separate safety breakdown for participants who continued with Hi-VNI and those who were intubated. The record also lists no top serious-event terms.

These are the recorded counts, not evidence that the risk of an event is absent. A zero count means no events were recorded in the listed group for the reported safety fields. It does not establish that an event could not occur, and it does not show how complete the event ascertainment was. The registry record does not report further details about safety definitions, collection procedures, or a separate follow-up account beyond the outcome timeframe listed for the primary endpoint.

The serious-event figures should be read separately from the primary surgical completion outcome. They do not tell readers how often surgery was completed using Hi-VNI alone, how often conversion occurred, or whether an alternative oxygenation method was needed. Those primary outcome results are not reported in the registry record.

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

The record documents a completed study of Hi-VNI use during upper airway surgery, including the stated oxygenation settings, conversion thresholds, and intended surgical completion endpoint. It also records an enrollment of 31 and serious adverse event and death counts of zero in the listed safety group. These are descriptive details about the registry entry.

The record does not report the primary endpoint counts or a statistical analysis of them. Consequently, it cannot show how many cases were completed using only Hi-VNI, how many were completed after conversion, or how many did not meet the completion outcome. Without those results, there is no reported estimate or uncertainty interval from which to judge the observed completion experience. The completed status of the study does not fill this reporting gap.

The study design also limits the kind of inference that could be made. It is recorded as single-group, without randomized allocation. The registry describes conversion to an alternative oxygenation method when specified thresholds were reached, but conversion is not a randomized comparator. The record therefore does not establish a causal difference between Hi-VNI and another oxygenation approach.

The serious-event record reports no serious events and no deaths in the listed group, but those counts do not prove that the technique is free of risk or establish the safety of one approach relative to another. The record does not provide a separate safety comparison by oxygenation method. In general, a zero observed count remains a description of the recorded experience, not a guarantee about future outcomes.

In short, the registry supports a description of the study’s aims, design, and specified procedures. It does not support a numerical conclusion about the primary outcome, a claim about comparative effectiveness, or a complete assessment of precision and missing data. Those conclusions would require outcome results and analysis details that are not reported in the registry record.

13. Why This Trial Matters Statistically

This study raises a practical statistical question: how should completion be defined when the intended oxygenation technique may be supplemented or replaced during a procedure? A measure that counts completion with or without conversion answers a different question from a measure limited to completion using only Hi-VNI. Keeping these outcomes distinct can make the clinical meaning of an endpoint clearer and help readers understand what a count represents.

The registry’s description also illustrates why design labels matter. A single-group study can describe what occurred under its study approach, but does not create a randomized counterfactual. Participants converted to another oxygenation method are not equivalent to participants randomly assigned to that method. Treating them as a control group would risk confusing a response to the participant’s circumstances with an effect of the oxygenation method.

Transparent outcome reporting is essential to interpretation. Enrollment and study completion do not tell readers how many participants met the primary outcome, how many required conversion, or how precise any estimate may be. Without those counts and denominators, the stated clinical question remains unanswered in the registry record. Reporting the endpoint definition, analysis population, missing outcomes, and uncertainty would allow readers to distinguish an observed description from a comparative inference.

The record’s planning assumptions also offer a useful reminder: sample-size illustrations are conditional on their assumptions and are not observed evidence. In particular, a hypothetical two-arm planning calculation should not be read as a description of a study recorded as single-group. Separating design assumptions from results helps prevent planning tools from being mistaken for findings.

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.

The principal limitation for statistical interpretation is that the registry record does not report the primary endpoint result or an analysis. The record does not give the counts for completion using only Hi-VNI, completion after conversion, or other completion outcomes. It also does not report an outcome-specific denominator or confidence interval. This prevents assessment of the observed result and its precision.

The endpoint wording is not fully resolved in the record. It refers to assessing completion using only Hi-VNI, while the primary outcome is described as completion with or without conversion. Without a clear final operational definition and category counts, readers cannot determine how the primary endpoint treated converted cases.

The study is single-group and has no randomized comparator. Any descriptive contrast between participants who did and did not require conversion would be vulnerable to differences in the circumstances associated with conversion. The record does not report an adjusted comparison or other method that would support a causal comparison.

The registry lists an enrollment of 31, but does not report how many participants contributed to the primary endpoint analysis or whether any outcomes were missing. It does not describe the analysis population, missing-data methods, or sensitivity analyses. The protocol, sample-size justification, statistical analysis plan, interim analyses, and methods for endpoint adjudication are also not reported in the registry record.

Safety interpretation is limited by the lack of a separate breakdown for participants by oxygenation experience and by the absence of further safety-collection details. The recorded zero serious events and deaths should therefore be understood as the counts in the registry entry, not as evidence that risk was absent.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: High Velocity Nasal Insufflation (Hi-VNI) Use in Upper Airway Surgery — NCT05090852.
• Registry record last updated 2022-10-13; status last verified 2022-09.
• Results first posted 2022-09-19.
• 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

The registry record describes NCT05090852, “High Velocity Nasal Insufflation (Hi-VNI) Use in Upper Airway Surgery,” as a completed, single-group study with enrollment of 31. The listed condition is upper airway surgery, and Hi-VNI is the device intervention. The study began on 2020-10-22 and had a primary completion date of 2021-09-30.

The primary outcome concerns surgical case completion using Hi-VNI, with or without conversion to another oxygenation method, over a timeframe of 1 day. The description specifies a flow rate of 40 L/min and FiO2 of 100%, with conversion described for SpO2 < 93 or TcCO2 > 65. The primary outcome counts and analysis are not reported in the registry record.

The safety record lists zero serious adverse events and zero deaths for the displayed group, with 31 at risk. The registry records no analyses. Its design and reporting therefore support a description of the intended study approach, but not a numerical conclusion about the primary outcome or a randomized comparison with an alternative oxygenation strategy.