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The Effects of Vertical Position on Gas Exchange in Patients With Respiratory Failure

The Effects of Vertical Position on Gas Exchange in Patients With Respiratory Failure

Status
Active, not recruiting
Phases
NA
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT01705119
Enrollment
16
Registered
2012-10-12
Start date
2012-10-01
Completion date
2026-12-31
Last updated
2026-01-13

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Respiratory Failure

Keywords

Mechanically Ventilated, Critical Care

Brief summary

The purpose of this study is to investigate how changing from a supine to upright position affects gas exchange for patients with hypoxemic respiratory failure. The research question is: will oxygen saturation and/or partial pressure of oxygen in the blood change when a patient with hypoxemic respiratory failure moves from a supine to upright position?

Detailed description

Our hypothesis is that blood oxygen tension will not decrease and may even increase when a patient with respiratory failure stands up. Supine positioning often causes partial lung collapse, which results in a decreased amount of lung being available for gas exchange. In patients with Acute Respiratory Distress Syndrome (ARDS), tilting the patient up in bed has been shown to increase oxygen tension and improve lung compliance. Positional changes are sometimes used as a rescue intervention in patients with severe hypoxemia from ARDS. The investigators hope to conclude that severe hypoxemia should not be viewed as a contraindication to physical therapy, but rather physical therapy may be a potential intervention for patients with marginal gas exchange. After sedative interruption, physical therapists and nursing staff will assist mechanically ventilated patients in moving to the side of the bed. They will assess the extremity strength using the MRC scale. If lower extremity strength is at least 4/5, the patient will be assisted to assume the upright position. The investigators will monitor the patient continuously and the session will be stopped at any point for A. Mean arterial pressure \<65 B. Heart rate \<40, \>130 beats/min C. Respiratory rate \<5, \>40 breaths/ min D. Pulse oximetry \<88% E. Marked ventilator dyssynchrony F. Patient distress G. New arrhythmia H. Concern for myocardial ischemia I. Concern for airway device integrity J. Endotracheal tube removal At this point, the patient's vital signs, pulse oximetry, and measures of lung compliance will be obtained. If an arterial line is in place and there have been ventilator adjustments since the morning arterial blood gas, the investigators will draw an arterial blood gas. The physical therapists and nursing staff will then help the patient stand up. After one minute, the investigators will record another set of vital signs, pulse oximetry, and measures of lung compliance from the mechanical ventilator. If an arterial line is in place, the investigators will draw another arterial blood gas. The patient will then be assisted back into bed. One hour later, the investigators will record the patient's vital signs, pulse oximetry, and measures of lung compliance from the mechanical ventilator.

Interventions

Sponsors

University of Chicago
Lead SponsorOTHER

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* Patients aged ≥18 years who are mechanically ventilated * An oxygen saturation of 88-94% or an arterial line

Exclusion criteria

* Mean arterial pressure \<65 * Heart rate \< 40 or \> 130 beats/min * Respiratory rate \< 5 or \> 40 breaths/min * Pulse oximetry \< 88% * Evidence of elevated intracranial pressure * Active gastrointestinal blood loss * Active myocardial ischemia * Pregnancy * Actively undergoing a procedure * Patient agitation requiring increased sedative administration in the last 30 mins * Insecure airway (device) * The patient was not ambulatory prior to hospitalization * The patient's body habitus and/or mental status make it unsafe to stand up * The patient has been placed on strict bed rest by the treating physicians

Design outcomes

Primary

MeasureTime frame
PaO2 to FiO2 ratiochange from baseline to 1 hr

Secondary

MeasureTime frame
Oxygen Saturationchange from baseline to 1 hr
change in blood PCO2change from baseline to 1 hr
Change in blood pHchange from baseline to 1hr

Other

MeasureTime frame
Tidal Volumechange from baseline to 1 hr
Vital Signschange from baseline to 1hr

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026