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Postoperative ComplicationsINSPIRANCT04558151

Randomized-controlled Trial of Preoperative Inspiratory Muscle Training on Postoperative Complications

A study testing preoperative inspiratory muscle training in people with Postoperative Complications and Breathing Exercises, run by University of Zurich at 1 site in Switzerland.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

Rehabilitation strategies after abdominal surgery enhance recovery and improve outcome. A cornerstone of rehabilitation is respiratory physiotherapy with inspiratory muscle training to enhance pulmonary function. Read more about this study

Who is it for?
Ages 18 years and olderHealthy volunteers can take part
What is being tested?
preoperative inspiratory muscle training
Could I receive a placebo?
No, everyone receives an active treatment
How many people
134 participants
Where
1 siteSwitzerland
Study dates
13 Aug 2021to 8 Oct 2025
Phase
Interventional
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • Healthy volunteers accepted
  • Adult, Older adult

Who may be able to join

  • Informed Consent as documented by signature (Appendix Patient Informed Consent Form)
  • Planned abdominal surgery with planned duration >2hours (disease localization: upper vs. lower gastro intestinal, HPB, hernia, others)
  • Planned surgery at least two weeks after inclusion at outpatient clinic
  • Male and female patient over 18 years

Who cannot join

  • Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia, of the participant
  • Known or suspected non-compliance, drug or alcohol abuse,
  • Previous enrolment into the current study
  • Participation in another study with inspiratory muscle training within 30 days preceding or during this study

Trial locations and contacts

1 site in 1 country.

Switzerland1 site

  • University Hospital Zurich

    Zurich

Other trials in Switzerland

About this study

Official title: Randomized-controlled Trial of Spirometry-Assisted Preoperative INSPIRAtory Muscle Training on Postoperative Complications in Abdominal Surgery in a Single Tertiary Referral Centre

Rehabilitation strategies after abdominal surgery enhance recovery and improve outcome. A cornerstone of rehabilitation is respiratory physiotherapy with inspiratory muscle training to enhance pulmonary function. Prehabilitation is the process of enhancing functional capacity before surgery in order to compensate for the stress of surgery and postoperative recovery. There is growing interest in deploying pre-habilitation interventions prior to surgery.

The aim of this study is to assess the impact of preoperative inspiratory muscle training on postoperative overall morbidity. The question is, whether inspiratory muscle training prior to elective abdominal surgery reduces the number of postoperative complications and their severity grade.

Read the detailed description

INSPIRA is a prospective randomized-controlled single-center trial, non-blinded The aim of this study is to assess the impact of preoperative inspiratory muscle training on postoperative overall morbidity. The question is, whether inspiratory muscle training prior to elective abdominal surgery reduces the number of post-operative complications and their severity grade.

Furthermore, the impact of preoperative inspiratory muscle training on postoperative physiotherapeutic performance as surrogate of convalescence is assessed, too.

Patients will be instructed by physiotherapists to perform inspiratory muscle training containing of 30 breaths twice a day for 14-18 days before surgery using Power®Breathe KHP2.

Primary outcome is Comprehensive Complication Index (CCI) at 90 days after surgery. The CCI expresses morbidity on a con-tinuous numeric scale from 0 (no complication) to 100 (death) by weighing all postoperative complications according to the Clavien-Dindo classification for their respective severity.

Being tested
preoperative inspiratory muscle training
Keywords
inspiratory muscle training, CCI, postoperative complications, prehabilitation, preoperative respiratory training
Medical subject headings
Postoperative Complications

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • preoperative inspiratory muscle trainingBehavioural

    Physiotherapists will measure the maximal inspiration pressure (MIP) with the POWER®breathe device of each single patient. Patients will then be instructed to perform inspiratory muscle training at the level of 60% of their individual MIP. Patients are instructed to perform the training containing of 30 breaths twice a day for 14-18 days before surgery. The devices are able to register the performance of each single training session and training results are monitored.

Study groups in NCT04558151
Study groupRoleWhat they receive
Training armExperimentalPatients perform inspiratory muscle training containing of 30 breaths twice a day for 14-18 days before surgery.
Receives: Behavioral: preoperative inspiratory muscle training
Control armNo interventionNo preoperative inspiratory muscle training

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Postoperative complications

    Postoperative complications measured by the comprehensive complication index (CCI) Com-prehensive Complication Index (CCI) 90 days after surgery. The CCI expresses postoperative morbidity on a continuous numeric scale from 0 (no complication) to 100 (death) by weighing all postoperative complications according to the validated Clavien-Dindo classification for their respective severity. It is measured at the end-of hospitalization and 90 days after surgery to include cases in which a readmission was necessary. Postoperative complications are gold standard in evaluation of quality of surgery as they directly reflect the procedures out-come and are most relevant for the patients.

    Measured: 90 days postoperative

Secondary outcomes (10)

  1. Postoperative morbidity

    Secondary endpoints are the postoperative morbidity along the classification of Clavien-Dindo at the end of hospitalization as well as 90 days +/- 2 weeks after surgery. This classification consists of five (1-5) severity grades. Grade 1 reflects minor complications, while grade 5 re-flects death. The classification is widely accepted and validated to report postoperative compli-cations.

    Measured: At the end of hospitalization and 90 days +/- 2 weeks postoperative

  2. Length of hospital stay (LOS)

    Length of postoperative hospital stay

    Measured: 90 days postoperative

  3. Readmission rate

    Readmission rate as reflection of postoperative outcome.

    Measured: 90 days postoperative

  4. Mortality

    Mortality as reflection of postoperative outcome.

    Measured: 90 days postoperative

  5. Maximum inspiratory pressure (MIP)

    MIP is the most commonly used measure to evaluate inspiratory muscle strength. Very sensitive in detecting early respiratory muscle dysfunction, it allows for the assessment of ventilatory failure, restrictive lung disease and respirato-ry muscle strength and therefore represents a clinically meaningful trial endpoint.

    Measured: 5 days after surgery

  6. Load

    Load (cmH20) (LOAD) is a measure of resistance to inhalation, and represents the pressure generated in the airways due to the force of the inspiratory muscles during a training session. As the training load decays with increasing lung volume (in order to match the length tension characteristics of the inspiratory muscles), the load displayed corresponds to the resistance at the start of inhalation (i.e. at RV). A higher load result means that the patient is training their inspiratory muscles hard-er, leading to stronger muscles. Stronger inspiratory muscles will need to work less hard to cope with the demands of breathing, leading to reduced breathlessness

    Measured: 5 days after surgery

  7. Power (Watt)

    POWER is a measure of muscle performance which combines strength and speed of move-ment (Pressure x Flow). More powerful muscles will be more resistant to fatigue at a given level of work and therefore, breathlessness will be reduced. The value displayed is the average power for all breaths in a training session.

    Measured: 5 days after surgery

  8. Sit-to-stand test

    During the sit-to-stand test, the quantity [n] how often a patient can sit down on a chair and stand up during 60 seconds is noted. These values are evaluated at admission to hospital for surgery and 5 days after surgery.

    Measured: 5 days after surgery

  9. Energy (Joule)

    Breathing Energy) is a measure of the mechanical work (or effort) of breathing during your breathing training session. It is a result which combines the force exerted by your inspiratory muscles and the volume of air inhaled. The higher the value of breathing energy you attain, the longer and harder you have worked your inspiratory muscles.

    Measured: 5 days after surgery

  10. Volume (l)

    Lung volume refers to the volume of gas the lungs and it represents the functions of the respiratory muscles and the mechanics of the lung and chest .

    Measured: 5 days after surgery

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted22 Sep 2020
  2. Study start13 Aug 2021
  3. Primary completion8 Oct 2025
  4. Study completion8 Oct 2025

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Prevention
Allocation
Randomised
Intervention model
Parallel groups
Model description
Prospective randomized-controlled single-center trial, non-blinded
Masking
None (open label)
Enrolment
134 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT04558151
Sponsor's protocol ID
2020-PreopInsp
Acronym
INSPIRA
Status last verified
Dec 2025
First submitted
15 Sep 2020
Last updated
7 Jan 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Publications

  • Birrer DL, Kuemmerli C, Obwegeser A, Liebi M, von Felten S, Pettersson K, Horisberger K. INSPIRA: study protocol for a randomized-controlled trial about the effect of spirometry-assisted preoperative inspiratory muscle training on postoperative complications in abdominal surgery. Trials. 2022 Jun 7;23(1):473. doi: 10.1186/s13063-022-06254-4.

    PubMed 35672861

Questions about this trial

What is this clinical trial studying?

A study testing preoperative inspiratory muscle training in people with Postoperative Complications and Breathing Exercises, run by University of Zurich at 1 site in Switzerland.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 4 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 7 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Postoperative complications (time frame: 90 days postoperative). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT04558151, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 7 Jan 2026.

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