Pulmonary Function by Litter Position

April 6, 2026 updated by: University of California, San Francisco
A litter is often needed to extract a person from an austere environment like the wilderness or from confined, urban spaces. A horizontal litter is generally assumed to be better for patient care, but often makes for a more difficult, if not impossible, evacuation from some settings such as confined space rescue, cave rescue, or wilderness rescue when the litter must be moved up or down a cliff with an undercut edge. A litter in a vertical orientation is easier to move in these situations, which may expedite movement towards definitive care. In some wilderness rescue circles, the mantra is that movement IS definitive care. It is already known that lying flat on the ground negatively affects pulmonary function compared to a sitting baseline.1 It is possible that a vertically oriented litter is better for a subset of patients with respiratory issues than a horizontal litter. The investigators hypothesize that pulmonary function measured by FEV1, FVC, and FEV1/FVC, is better in simulated patients in a vertically oriented litter compared to a horizontally oriented one.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Enrolling by invitation

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.

Detailed Description

Objective To quantify changes in pulmonary function tests (PFTs) based on litter position.

Hypotheses:

  • Compared to sitting baseline, all PFTs in the litter will have decreased forced vital capacity (FVC) and 1 second forced expiratory volume (FEV1).
  • Compared to lying down, persons straight upright and pitched forward will have better forced vital capacity (FVC) and 1 second forced expiratory volume (FEV1).
  • We do not hypothesize any changes in FEV1/FVC.

Study Design This randomized crossover study will use twelve healthy volunteers. All subjects will do baseline sitting pulmonary testing. Experimental order is balanced to avoid any training effects. Choice of sequence will be by random selection of envelope.

Methods Once consented, included subjects will do baseline sitting measurement of FEV1 and FVC which will give FEV1/FVC. Each subject will then be secured in a Ferno-Washington Model 71 litter wearing their own type 2 or 3 harness, or in a UL tested CMC ATOM Global Harness (California Mountain Corporation, Santa Barbara, CA) meeting ANSI Z359.11-2014 and NFPA 1983-2017 standards, if they don't have their own. The person will be secured with double Vs from the litter sides to the harness and footloops supporting them so their weight is on their feet and only minimally on the harness (if vertical). This process is consistent with industry standards for securing a patient in the litter and follows the specific model of the National Cave Rescue Commission.3 See figure 1 Prior to being secured in the litter the patient will do sitting baseline FEV1 and FVC with an NDDD spirograph. Once there is baseline data the subject will be secured in the litter. The investigators will then repeat spirometry, pulse, and blood pressure in a horizontal position (see figure 2), in a vertical position (see figure 3), and pitched slightly forward in a position that results from a Pike and Pivot rigging for raising up past a difficult cliff edge (see figure 4). The subject will get a rest period in their preferred position until pulse returns to within 5 beats of baseline.

Litter suspension will be with a four-legged litter spider when horizontal, with a high bridle tied directly to the litter head for the full vertical position, and from a low bridle in Pike-and-Pivot formation when pitched forward. The litter will be lifted into position with a 3:1 mechanical advantage system tied to an anchor. No matter the position, the lowest point of the litter will be no more than 6 inches off of the ground. The system will be configured for immediate lower for any expressed concern. The PI (RM) is a technical rescue instructor for the National Cave Rescue Commission and Assistant Training Officer-Technical Rescue for Fresno County search and rescue. The Co-PIs (SS and SD) are on the rope team of Fresno County search and rescue. Each is well versed in rope systems, anchor selection, and patient packaging.

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.
12

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 Contact Backup

Study Locations

  • United States
    • California
      • Fresno, California, United States, 93701
        • UCSF Fresno

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

Yes

Description

Inclusion Criteria:

  • 130-310 pounds

Exclusion Criteria:

  • Significant cardiac or pulmonary diseae

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: Supportive Care
  • Allocation: Randomized
  • Interventional Model: Sequential Assignment
  • Masking: None (Open Label)

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.
Active Comparator: Flat
Secured in a flat litter
Other: LItter position PFTs
Testing basic pulmonary function in three positions in a rescue litter, compared to sitting baseline
Active Comparator: Vertical
Secured in a vertical litter
Other: LItter position PFTs
Testing basic pulmonary function in three positions in a rescue litter, compared to sitting baseline
Active Comparator: Pitched forward
Secured in a litter leaning forward
Other: LItter position PFTs
Testing basic pulmonary function in three positions in a rescue litter, compared to sitting baseline
Placebo Comparator: Baseline
Sitting baseline pulmonary function
Other: LItter position PFTs
Testing basic pulmonary function in three positions in a rescue litter, compared to sitting baseline

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
Measure Description
Time Frame
Forced Vital Capacity
Time Frame: Immediately
Measurable lung volume on expiration
Immediately

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
FEV1
Time Frame: Immediately
Air volume exhaled in 1 second
Immediately

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.
University of California, San Francisco

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Roger B Mortimer, MD, UCSF - Fresno

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.
February 15, 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.
April 1, 2026

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.
April 1, 2026

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).
September 19, 2025

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.
October 17, 2025

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.
October 21, 2025

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.
April 8, 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.
April 6, 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.
April 1, 2026

More Information

Terms related to this study

Keywords

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.
  • 25-45106

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Deidentified data will be submitted to a statistician

IPD Sharing Time Frame

1/1/26 to 6/1/26

IPD Sharing Access Criteria

Roger Mortimer, MD Sarah Davis, DO Sue Spano, MD Amanda Mortimer, PhD

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP

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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