Local Warming to Improve Pulse Oximetry Accuracy in Critically Ill Patients

NCT07792304 | Not Yet Recruiting

• 1 other identifier: PULSEWARM-RCT-01
• Study Type: interventional
• Target: 240
• Locations: 1 country
• Sites: 4

Brief Summary

Pulse oximeters are widely used in intensive care to continuously estimate the oxygen level in the blood. However, pulse oximeter measurements may be less accurate when blood flow to the fingers is poor, which is common in critically ill patients. This study will investigate whether warming the hand and lower part of the forearm can improve the accuracy of pulse oximeter measurements in mechanically ventilated adult intensive care patients with low blood flow to the fingers. Participants will be randomly assigned to either a local warming strategy or usual care without warming. In the warming group, the hand and lower forearm will be warmed for 15 minutes to a target temperature of 41-42°C. Pulse oximeter measurements will be compared with oxygen saturation measured from an arterial blood sample before and after the intervention. The main objective is to determine whether local warming reduces the difference between pulse oximeter oxygen saturation (SpO₂) and arterial oxygen saturation (SaO₂) 15 minutes after the start of the assigned strategy. The study will also assess whether any improvement persists at 60 minutes, how peripheral blood flow changes during 4 hours of follow-up, whether repeat warming is effective when blood flow decreases again, and whether the effect differs according to skin phototype. Safety related to the warming intervention will also be evaluated.

Conditions

Critical Illness; Low Peripheral Perfusion; Pulse Oximetry Accuracy

Keywords

Pulse oximetry Oxygen saturation; SpO₂; SaO₂; Peripheral perfusion Perfusion index; Skin pigmentation; Local warming; Fitzpatrick skin phototype; Critically ill patients; Arterial blood gas; Mechanical ventilation

Outcome Measures

Primary Outcomes (1)

• SpO2-SaO2 Bias at 15 Minutes

  Pulse oximetry bias is defined as peripheral oxygen saturation measured by pulse oximetry (SpO2) minus arterial oxygen saturation measured by blood gas analysis (SaO2), expressed in percentage points. The primary analysis will compare SpO2-SaO2 bias between the local warming and control groups at 15 minutes, adjusted for baseline bias and study site.

  15 minutes after initiation of the randomized strategy

Secondary Outcomes (6)

• SpO2-SaO2 Bias at 60 Minutes

  60 minutes after initiation of the randomized strategy

• Proportion of SpO2 Measurements Within ±2 Percentage Points of SaO2

  15 and 60 minutes after initiation of the randomized strategy

• Change in Finger Perfusion Index

  Baseline and 15, 60, 120, and 240 minutes

• Difference Between Finger and Earlobe Perfusion Index Response

  Baseline, 15 minutes, and 60 minutes

• Perfusion Index Response to Repeat Local Warming

  Up to 240 minutes after randomization

Other Outcomes (1)

• Treatment Effect on SpO2-SaO2 Bias According to Fitzpatrick Skin Phototype

  15 minutes after initiation of the randomized strategy

Study Arms (2)

Protocolized Local Warming

EXPERIMENTAL

Participants receive protocolized local warming applied to the dorsum of the hand and distal forearm for 15 minutes, targeting an interface temperature of 41-42°C. Repeat warming is permitted during follow-up if finger perfusion index decreases below 0.5.

Other: Protocolized Local Warming

Usual Care Without Protocolized Warming

NO INTERVENTION

Participants receive usual care without protocolized local warming. Oxygen therapy and all other clinical management are provided according to standard intensive care practice.

Interventions

Protocolized Local Warming OTHER

Local warming is applied to the dorsum of the hand and distal forearm for 15 minutes using a warming device adjusted to achieve a target interface temperature of 41-42°C. During follow-up, repeat warming is permitted if finger perfusion index decreases below 0.5.

Protocolized Local Warming

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age 18 years or older.
• Admitted to an intensive care unit.
• Receiving invasive mechanical ventilation via endotracheal tube or tracheostomy.
• Existing arterial catheter placed for a clinical indication.
• Objectively verified low peripheral perfusion, defined as finger perfusion index (PFI) \<1.0 at screening.
• Stable baseline pulse oximetry signal permitting calculation of the SpO2-SaO2 difference.
• Clinical condition considered sufficiently stable to allow study measurements without interfering with ongoing treatment.

You may not qualify if:

• Absence of a stable baseline pulse oximetry signal on all available sensors, preventing calculation of the SpO2-SaO2 difference.
• Skin injury, burn, infection, or other local skin condition of the hand or forearm that prevents safe application of the warming pad or pulse oximetry sensor.
• Clinical instability for which the treating physician considers study participation likely to interfere with acute treatment or patient safety.
• Known hypersensitivity to materials used in the warming pad or sensors.
• Participation in another ongoing interventional study that could affect the primary outcome.

Sponsors & Collaborators

• Vastra Gotaland Region: lead
• North Älvsborg County Hospital, Trollhättan: collaborator
• Skaraborg Hospital: collaborator

Study Sites (4)

Sahlgrenska University Hospital

Gothenburg, Sweden

Location

Kungälvs Sjukhus

Kungälv, Sweden

Location

Skaraborgs Sjukhus

Skövde, Sweden

Location

Norra Älvsborgs Sjukhus

Trollhättan, Sweden

Location

MeSH Terms

Conditions

Critical Illness; Pigmentation Disorders

Condition Hierarchy (Ancestors)

Disease Attributes; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Skin Diseases; Skin and Connective Tissue Diseases

Central Study Contacts

Carl Sjödin, PhD student

CONTACT

0707163277; carl.sjodin@vgregion.se

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: SUPPORTIVE CARE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER GOV
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: PhD Student

Model Details: Participants are randomized 1:1 to a protocolized local warming strategy or usual care without protocolized warming. Randomization is stratified by study site and Fitzpatrick skin phototype.

Study Record Dates

• First Submitted: August 24, 2026
• First Posted: August 28, 2026
• Study Start (Estimated): October 1, 2026
• Primary Completion (Estimated): October 1, 2028
• Study Completion (Estimated): December 1, 2028
• Last Updated: August 28, 2026

Record last verified: 2026-08

Locations

SE (4)