Spontaneous vs Controlled Mechanical Ventilation in Acute Hypoxemic Respiratory Failure
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: Spontaneous Ventilation Strategy, Controlled Ventilation Strategy.
- Who it may be relevant to
- Registry conditions: Acute Respiratory Distress Syndrome (ARDS), Acute Hypoxemic Respiratory Failure. Basic parameters: from 18 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Center list to be confirmed — check the primary protocol.
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
Unsure about the terms? Read our patient guide →
Official title
Spontaneous Versus Controlled Mechanical Ventilation in Patients With Acute Hypoxemic Respiratory Failure: A Feasibility Study and Pilot Trial
Overview
Acute hypoxemic respiratory failure may progress to acute respiratory distress syndrome, a life-threatening condition that often requires mechanical ventilation. The optimal ventilation strategy in this patient population remains uncertain. The SVALBARD trial is a feasibility and pilot study designed to compare spontaneous versus controlled mechanical ventilation in patients with acute hypoxemia respiratory failure. The primary objective is to assess the feasibility of the study procedures and interventions, while also collecting descriptive data on key clinical variables to inform the design of a future randomized controlled trial.
Detailed description
Acute hypoxemic respiratory failure is a condition that can progress to acute respiratory distress syndrome (ARDS), requiring invasive mechanical ventilation to support gas exchange and limit lung injury. ARDS guidelines recommend lung-protective ventilation strategies-specifically low tidal volumes and limited airway pressures-to reduce ventilator-induced lung injury. Observational studies, including the global LUNG SAFE project, have described the epidemiology and management of acute hypoxemic respiratory failure and ARDS. These studies report high mortality rates (global hospital mortality, 38.6%) associated with the severity of lung injury rather than strict fulfilment of ARDS criteria. They also reveal variability in the application of evidence-based ventilation strategies across institutions. This inconsistency highlights a barrier to progress: the lack of conclusive evidence guiding ventilation management in patients with acute hypoxemic respiratory failure.
One unresolved issue is the role of spontaneous breathing during mechanical ventilation. Observational studies suggest that allowing spontaneous effort may reduce need for sedation and increase ventilator-free days. In contrast, preclinical models indicate that spontaneous breathing in severe lung injury may worsen outcomes through mechanisms such as patient-ventilator asynchrony and regional overdistension. This contrast underscores the need to balance potential benefits against physiological risks in the absence of adequate trial data. ARDS guidelines do not provide clear recommendations on this issue due to limited evidence. Only one large RCT has compared controlled ventilation to spontaneous breathing modes, finding no difference in short-term outcomes and not assessing long-term endpoints such as cognitive impairment or quality of life.As a result, clinicians must choose between guideline-based controlled ventilation and approaches that incorporate spontaneous breathing, within the context of evolving sedation practices and recovery goals. Given the variability of acute hypoxemic respiratory failure and the current evidence gap, genuine uncertainty ('clinical equipoise') exists regarding the optimal ventilation strategy. This supports the need for well-designed RCTs to determine whether spontaneous ventilation offers clinical benefit or harm. A recent survey of Nordic clinicians showed support for such a trial in patients with moderately severe acute hypoxemic respiratory failure, underscoring the relevance of this research.
The SVALBARD study is a feasibility and pilot trial comparing spontaneous and controlled mechanical ventilation in patients with acute hypoxemic respiratory failure. The study will evaluate whether it is possible to recruit patients, apply the assigned ventilation strategies, and collect the required data in a reliable way.
In addition, the study will collect descriptive clinical data to better understand patient characteristics and outcomes. The results will be used to improve the design and planning of a future randomized controlled trial.
The trial will accrue 80 patients from eight different intensive care units, four in Norway and four in Denmark.
Interventions
- Procedure Spontaneous Ventilation Strategy
Invasive mechanical ventilation strategy allowing spontaneous breathing while receiving ventilatory support from a standard ICU mechanical ventilator. - Procedure Controlled Ventilation Strategy
Invasive mechanical ventilation strategy in which spontaneous respiratory effort is suppressed and breaths are fully delivered by a standard ICU mechanical ventilator.
Primary outcome measures
- Recruitment Rate [Time frame: 1 year from trial initiation]
Secondary outcome measures (12)
- Consent Rate [Time frame: 1 year from trial initiation]
- Randomisation Rate [Time frame: 1 year from trial initiation]
- Protocol Adherence [Time frame: 1 year from trial initiation]
- Major Protocol Violations [Time frame: 1 year from trial initiation]
- Retention Rate [Time frame: 1 year from trial initiation]
- Time to Completion of Feasibility Study [Time frame: Up to 1 year]
- Proportion of Participants Achieving Therapeutic Target at 48 Hours [Time frame: 48 hours from randomisation]
- Between-Group Difference in Therapeutic Target Attainment at 48 Hours [Time frame: 48 hours]
- Proportion of Missing Therapeutic Target Data at 48 Hours [Time frame: 48 hours from randomisation]
- Clinical: All-Cause Mortality at 30 Days [Time frame: 30 days]
- Clinical: All-Cause Mortality at 90 Days [Time frame: 90 days]
- Clinical: All-Cause Mortality at 180 Days [Time frame: 180 days]
Eligibility criteria
Inclusion criteria
We will include patients who fulfil all the following criteria:
- Acutely admitted to the ICU
- AND age ≥ 18 years
- AND invasive mechanical ventilation via endotracheal tube or tracheostomy for less than 24 hours
- AND moderate acute hypoxemic respiratory failure, defined as a PaO₂-FiO₂ ratio between 13.3-26.6 kPa (100-200 mmHg) with PEEP ≥ 5 cm H2O, based on arterial blood gas analysis obtained within 2 hours before randomisation.
- AND new pulmonary infiltrate (uni- or bilateral) on chest x-ray or CT-scan obtained no more than 24 hours before randomisation.
Exclusion criteria
- Previously randomised into the SVALBARD trial.
- Informed consent following inclusion expected to be unobtainable
- Patient under coercive measures
- Withdrawal from active therapy or brain death deemed imminent.
- Chronic hypercapnic respiratory failure defined as PaCO2 > 8 kPa (60 mm Hg) in the outpatient setting.
- Listed for lung transplant.
- Acute heart failure / acute myocardial infarction / cardiac arrest during or causing index ICU admission.
- Use of home oxygen.
- Chronic mechanical ventilation for any reason except for non-invasive mechanical ventilation (CPAP/BIPAP) used solely for sleep apnoea disorder.
- Currently receiving ECMO therapy.
- Burns >70 % total body surface.
- Acute brain injury or stroke (any, including subarachnoid haemorrhage, SAH).
- Intracranial hypertension.
- Patients with planned repeat surgical interventions during current stay in ICU.
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: No
Study design
- Allocation
- Randomized
- Model
- Parallel assignment
- Masking
- Single blind
- Primary purpose
- Treatment
Study locations
Center list to be confirmed — check the primary protocol.
Publications
- Aslam TN, Klitgaard TL, Ahlstedt CAO, Andersen FH, Chew MS, Collet MO, Cronhjort M, Estrup S, Fossum OK, Frisvold SK, Gillmann HJ, Granholm A, Gundem TM, Hauss K, Hollenberg J, Huanca Condori ME, Hastbacka J, Johnstad BA, Keus E, Kjaer MN, Klepstad P, Krag M, Kvale R, Malbrain MLNG, Meyhoff CS, Morgan M, Moller A, Pfortmueller CA, Poulsen LM, Robertson AC, Schefold JC, Schjorring OL, Siegemund M, PMID 37737652
- Aslam TN, Klitgaard TL, Moller MH, Perner A, Hofso K, Skrubbeltrang C, Rasmussen BS, Laake JH. Spontaneous Versus Controlled Mechanical Ventilation in Patients With Acute Respiratory Distress Syndrome-A Scoping Review. Acta Anaesthesiol Scand. 2025 Sep;69(8):e70096. doi: 10.1111/aas.70096. PMID 40757745
- Aslam TN, Klitgaard TL, Moller MH, Perner A, Hofso K, Skrubbeltrang C, Flaatten HI, Rasmussen BS, Laake JH. Spontaneous versus controlled mechanical ventilation in patients with acute respiratory distress syndrome - Protocol for a scoping review. Acta Anaesthesiol Scand. 2020 Jul;64(6):857-860. doi: 10.1111/aas.13570. Epub 2020 Mar 20. PMID 32157683
- Laake JH, Smastuen MC, Moller MH, Larsson A, Aslam TN, Hofso K, Pham T, Fan E, Bellani G, Laffey JG; LUNG SAFE Investigators. Patient characteristics, management and outcomes in a Nordic subset of the "large observational study to understand the global impact of severe acute respiratory failure" (LUNG SAFE) study. Acta Anaesthesiol Scand. 2022 Jul;66(6):684-695. doi: 10.1111/aas.14069. Epub 2022 M PMID 35398892
- Aslam TN, Klitgaard TL, Hofso K, Rasmussen BS, Laake JH. Spontaneous Versus Controlled Mechanical Ventilation in Patients with Acute Respiratory Distress Syndrome. Curr Anesthesiol Rep. 2021;11(2):85-91. doi: 10.1007/s40140-021-00443-8. Epub 2021 Mar 3. PMID 33679255
Identifiers
NCT: NCT07463885 · UTN: U1111-1335-7858