An interventional study of Protocolized Local Warming in Critical Illness, Low Peripheral Perfusion and Pulse Oximetry Accuracy, sponsored by Vastra Gotaland Region. Not yet recruiting at 4 sites in Sweden. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-25.
Sponsored by Vastra Gotaland Region · Not applicable, Interventional, and Supportive care
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.
Pulse oximetry is a fundamental component of monitoring and oxygen titration in critically ill patients. Its accuracy may, however, be impaired by reduced peripheral perfusion. Low peripheral perfusion is common in mechanically ventilated intensive care patients and may contribute to clinically relevant differences between peripheral oxygen saturation measured by pulse oximetry (SpO₂) and arterial oxygen saturation measured by blood gas analysis (SaO₂).
Local warming increases cutaneous blood flow and is routinely used to improve peripheral perfusion during procedures such as capillary blood sampling. Preliminary single-center data suggest that local warming may also improve pulse oximetry accuracy in critically ill patients with low peripheral perfusion. Whether this effect is present when evaluated in a randomized controlled trial is unknown.
This is a prospective, multicenter, parallel-group randomized controlled strategy trial conducted in four intensive care units. Mechanically ventilated adult ICU patients with an arterial catheter and a finger perfusion index (PFI) \<1.0 will be randomized in a 1:1 ratio to a protocolized local warming strategy or usual care without protocolized warming. Randomization will be stratified by study site and Fitzpatrick skin phototype.
In the intervention group, local warming will be applied to the dorsum of the hand and distal forearm for 15 minutes, with a target interface temperature of 41-42°C. Repeat warming is permitted during follow-up if finger PFI decreases below 0.5 according to the prespecified study strategy. The control group will receive usual care without protocolized local warming.
SpO₂, finger PFI, earlobe PFI, and arterial SaO₂ will be assessed at baseline, 15 minutes, and 60 minutes. Additional PFI measurements will be obtained at 120 and 240 minutes. Oxygen therapy will otherwise be managed according to standard clinical care.
The primary objective is to compare pulse oximetry bias between the randomized groups at 15 minutes. Bias is defined as SpO₂ minus SaO₂, expressed in percentage points. The primary analysis will compare the groups using an analysis of covariance adjusted for baseline SpO₂-SaO₂ bias and study site.
Secondary objectives include assessment of pulse oximetry accuracy at 60 minutes, the proportion of measurements within ±2 percentage points of SaO₂, changes in peripheral perfusion during 4 hours of follow-up, the local versus systemic perfusion response assessed using finger and earlobe PFI, the response to repeat warming, safety outcomes, and possible treatment-effect modification according to Fitzpatrick skin phototype.
The planned sample size is 240 participants, with 120 participants allocated to each study group.
A prespecified single-center device-comparison substudy will be conducted within a subset of participants enrolled at Sahlgrenska University Hospital. In both the randomized warming and control groups, simultaneous pulse oximetry measurements will be obtained using multiple complete pulse oximetry systems applied to different fingers together with a non-warmed forehead pulse oximeter. Measurements will be obtained at the same predefined study time points and compared with SaO2 measured by blood gas analysis. The substudy will assess device-specific SpO2-SaO2 bias, differences in accuracy between pulse oximetry systems, and whether the effect of local warming on pulse oximetry accuracy differs across devices. The forehead sensor will provide a non-warmed comparison site. Mixed-effects models will include device, randomized treatment group, time, and their interactions, with repeated measurements within participants accounted for.
1,780 studies on the registry are indexed under Critical Illness; 442 are open to participants now.
This study's planned enrollment of 240 is above the median of 90 across 926 interventional studies indexed under Critical Illness.
Browse Critical Illness studies →Vastra Gotaland Region is the lead sponsor of 275 studies on the registry; 109 are open to participants now.
Compared within Critical Illness, the registry's first condition term, which may not be this study's main condition. Counted across the registry records on this site, refreshed daily. How we classify →
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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
Participants receive usual care without protocolized local warming. Oxygen therapy and all other clinical management are provided according to standard intensive care practice.
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.
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.
Time frame: 15 minutes after initiation of the randomized strategy
SpO2-SaO2 Bias at 60 Minutes
Pulse oximetry bias is defined as SpO2 minus SaO2, expressed in percentage points. Bias at 60 minutes will be compared between randomized groups to evaluate durability of the effect of the warming strategy.
Time frame: 60 minutes after initiation of the randomized strategy
Proportion of SpO2 Measurements Within ±2 Percentage Points of SaO2
The proportion of participants with an absolute difference between SpO2 and SaO2 of 2 percentage points or less will be determined at 15 and 60 minutes and compared between randomized groups.
Time frame: 15 and 60 minutes after initiation of the randomized strategy
Change in Finger Perfusion Index
Finger perfusion index (PFI) will be measured serially to assess the peripheral perfusion response to the randomized strategy and its durability during 4 hours of follow-up.
Time frame: Baseline and 15, 60, 120, and 240 minutes
Difference Between Finger and Earlobe Perfusion Index Response
Changes in perfusion index measured at the finger and earlobe will be compared to assess whether the perfusion response to local warming is predominantly local rather than systemic.
Time frame: Baseline, 15 minutes, and 60 minutes
Perfusion Index Response to Repeat Local Warming
Among participants in the warming group who undergo repeat warming because finger PFI decreases below 0.5 during follow-up, the change in finger PFI following repeat warming will be assessed to evaluate repeatability of the perfusion response.
Time frame: Up to 240 minutes after randomization
Warming-Related Adverse Events
Number of participants experiencing adverse events considered related to local warming, including skin injury, erythema requiring discontinuation of warming, or other prespecified adverse reactions during the study period.
Time frame: From initiation of the randomized strategy through 240 minutes
Treatment Effect on SpO2-SaO2 Bias According to Fitzpatrick Skin Phototype
Prespecified analysis of treatment-effect modification according to Fitzpatrick skin phototype. The interaction between randomized treatment group and Fitzpatrick skin phototype will be evaluated for the primary outcome of SpO2-SaO2 bias at 15 minutes.
Time frame: 15 minutes after initiation of the randomized strategy
Device-Specific SpO2-SaO2 Bias at 15 Minutes
SpO2-SaO2 bias, defined as SpO2 minus SaO2 in percentage points, will be determined separately for each pulse oximetry system in participants enrolled in the single-center device-comparison substudy. Bias will be compared across devices and between randomized warming and control groups.
Time frame: Baseline and 15 minutes after initiation of the randomized strategy
Change in Device-Specific SpO2-SaO2 Bias After Local Warming
The change in SpO2-SaO2 bias from baseline to 15 minutes will be calculated for each pulse oximetry system. The analysis will evaluate whether the change differs between devices and randomized treatment groups.
Time frame: Baseline to 15 minutes
Accuracy of Forehead Versus Finger Pulse Oximetry
SpO2-SaO2 bias and absolute agreement will be compared between finger-based pulse oximetry systems and a non-warmed forehead pulse oximeter.
Time frame: Baseline and 15 minutes after initiation of the randomized strategy
Plan to share: Undecided — The feasibility and conditions for sharing de-identified individual participant data have not yet been determined. Any future data sharing will be subject to applicable ethical approvals, data protection regulations, institutional policies, and appropriate data-sharing agreements.
No publications or documents are linked to this record.
Start is estimated for Oct 2026; primary completion for Oct 2028, 24 months later.
Of 399 non-industry interventional studies with no phase under Critical Illness, half reached primary completion within 21 months of starting (the median), counting those still running; a quarter within 12 and three quarters within 40. This study's planned 24 months is above that.
Counting every sponsor, half of 403 studies reached it within 21 months; a quarter within 12 and three quarters within 40.
Critical Illness covers many different conditions, not one, so the studies compared here vary widely. Read these figures as a rough guide.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Sep 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.