Postoperative High-flow Nasal Oxygenation After High-risk Surgery in the Frail Adult (Hi-POP)

May 11, 2026 updated by: Region Stockholm
High flow nasal oxygen (HFNO) in the immediate postoperative period has been demonstrated to reduce the risk of postoperative pulmonary complications (PPC) after cardiothoracic surgery. In specific groups of patients such as the obese and after upper abdominal surgery the results are contradictive. However, there is lack of evidence if HFNO in the general high-risk patient after abdominal and non-cardiac thoracic surgery can reduce the prevalence of PPC, hypoxaemia and escalation of therapy. Therefore, the investigators aim to compare the use of HFNO with conventional oxygen therapy (COT) in high-risk patients after abdominal and non-cardiac thoracic surgery regarding postoperative pulmonary complications.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
200

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

Adults (≥18 years old) scheduled for elective abdominal (laparotomy or laparoscopy), open abdominal vascular or non-cardiac thoracic surgery under general anaesthesia with an estimated duration over 3 hours.

AND

Meeting at least two of the following criteria:

  • Age > 65 years
  • BMI >30
  • Preoperative SpO2 <95 %
  • Scheduled for lobectomy or pulmonary segment resection
  • Respiratory tract infection the last month
  • Preoperative anaemia (Hb <100) or severe hypoalbuminemia (<20 g/L)
  • Current smoker or previous smoker with >30 packyears
  • Pulmonary disease or OSAS
  • Heart failure
  • Clinical frailty (CFS 4)

Exclusion Criteria:

  • Not suitable for postoperative HFNO, as decided by a study member or the anaesthetist in charge (such as total nasal obstruction, skull fracture, facial injuries)
  • Pregnancy
  • Not able to understand the study information or sign an informed consent.
  • Not able to participate with the treatment postoperatively
  • Planned for delayed extubation in the intensive care
  • Preoperative non-invasive ventilation due to respiratory failure or a higher level of care than a regular ward

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: HFNO
Group of patients receiving HFNO postoperatively
Combination product: High Flow Oxygen
High flow nasal oxygen will be administered in the intervention group
Active Comparator: Conventional oxygen therapy (COT)
Group of patients receiving conventional oxygen therapy postoperatively
Combination product: Oxygen
Oxygen delivered by nasal cannula or oxymask

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
Frequency of postoperative pulmonary complications (PPC) the first seven days after high-risk abdominal or non-cardiac thoracic surgery in high-risk patients with high-flow nasal oxygen or conventional oxygen therapy in the immediate postoperative period
Time Frame: Up to 7 days after surgery
Up to 7 days after surgery

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Lowest SpO2 the first 2 and 24 h after randomisation
Time Frame: 24 hours after randomisation
Lowest oxygen saturation registered in the chart during the first 2 and 24 h after randomisation
24 hours after randomisation
Desaturation (SpO2 <90%) the first 2 or 4 and under 24 hours after randomisation
Time Frame: First 24 hours after randomisation
Proportion of patients that has a registered oxygen saturation under 90% 2, 4 and 24 hours after randomisation
First 24 hours after randomisation
Lowest PaO2/FiO2 ratio during the intervention period
Time Frame: Maximum 4 hours after start of intervention postoperatively
Comparison of the lowest PaO2 and FiO2 (fraction of inspired oxygen) during the intervention period ( i e 2 or 4 hours depending of the result from the air test)
Maximum 4 hours after start of intervention postoperatively
Subjective patient comfort (visual scale 0-10)
Time Frame: Maximum 4 hours after start of intervention
Patients will report their comfort with each method, HFNO or COT after the intervention
Maximum 4 hours after start of intervention
Length of stay (LOS) in the postoperative unit
Time Frame: Up to 7 days after surgery
The duration of stay in the postoperative unit will be registered and compared between the groups
Up to 7 days after surgery
Length of stay in hospital
Time Frame: From surgery up until 30 days after surgery
The length of stay in hospital after surgery will be recorded and compared
From surgery up until 30 days after surgery
Mortality in hospital
Time Frame: Up until 30 days after surgery
Mortality during hospital admission after surgery
Up until 30 days after surgery
30-days mortality
Time Frame: 30 days after surgery
30-days mortality, number and proportion of patients between the groups
30 days after surgery
Healthy days at home 30 days after surgery
Time Frame: 30 days postoperatively
Number of healthy days at home 30 days after surgery compared between the groups
30 days postoperatively

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Region Stockholm

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Karolinska Institutet

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
April 20, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
March 9, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
March 9, 2029

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
February 19, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 9, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
March 11, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 14, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 11, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2026-00273-01

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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