Measure ID

Percentage of patients with active warming applied.

Measure Type
Available for Provider Feedback

General and neuraxial anesthesia causes vasodilation thus redistributing body heat from the core to peripheries.  This redistribution can cause hypothermia.  Core temperatures outside the normal range pose significant risks to patients. Pediatric patients are more likely to develop perioperative hypothermia due to a high surface area to weight ratio and inability to regulate their own temperature.1  Published research has correlated impaired wound healing, adverse cardiac events, altered drug metabolism, and coagulopathies with unplanned perioperative hypothermia. These adverse outcomes resulted in prolonged hospital stays and increased healthcare expenditures.  Active warming techniques provide the best results for reducing cutaneous heat loss and preventing hypothermia.2-7

Measure Time Period

Patients receiving general or neuraxial anesthesia (determined by Anesthesia Technique: General value code > 0 and Anesthesia Technique: Neuraxial value code >0).

  • ASA 5 & 6 including Organ Procurement (CPT: 01990)
  • Cases < 60 minutes (see other measure build details)
  • Procedures:
Success Criteria
  • Cases with documentation of an active warming device applied OR
  • Cases with at least one temperature greater than or equal to 36.0°C within the 30 minutes before case end through case end. See 'Other Measure Build Details' section for definition of case end time.
  • Other considerations:
Other Measure Details

The active warming (TEMP 01) measure will identify the percentage of cases in which an active warming device was applied between 'Case Start' and 'Case End' or the patient maintained a temperature above 36.0°C without active warming. In the event that active warming was not performed or documented, the case will meet the measure requirements if at least one temperature is greater than or equal to 36.0°C within 30 minutes of patient out of room.

Active warming is determined by Warming Method Classification value codes: 2, 4, 5, 96.

Active Warming includes:

  • Convective warming: forced air
  • Conductive warming: circulating water mattress, resistive heating electrical blankets
  • Endovascular warming, using a heat exchanging catheter (very rarely used)
  • Radiant heaters

Passive Warming interventions (NOT active warming):

  • Increasing ambient room temperature
  • Thermal insulators such as blankets
  • Fluid warmer (except for cesarean section)

Algorithm for determining Case Duration for Exclusion Criteria (<60 minutes):

Algorithm for determining Case End for 36.0°C Success Criterion:

Temperature Artifact algorithm:

  • Less than 32.0°C (89.6F)
  • Greater than 40.0°C (104.0F)
  • Any minute-to-minute jumps >0.5°C equivalent. 
    • Example: 0.125°C /15s, 0.25°C / 30s, 1°C / 2mins
  • Conversion from F to C:    F=32 +9/5 (°C)
  • If temperature site not present in physiologic concept, refer to intraop notes.
  • This measure uses the Warming Method Clasification and Warming Method Notes, which are not time bound

*This measure will include only valid MPOG cases as defined by the Is Valid Case phenotype.

Risk Adjustment

Not applicable.

Provider Attribution

Provider(s) present at Induction End. If not available, then Patient in Room. If Patient in Room not available, then Anesthesia Start.

MPOG Concept Used


  • 3050       Temp 1- Unspecified Site
  • 3051       Temp 2- Unspecified Site
  • 3052       Temp 1- Monitoring Site
  • 3053       Temp 2- Monitoring Site
  • 3031       Temperature- Temporal Artery
  • 3054       Temperature- Skin
  • 3055       Temperature- Esophageal
  • 3056       Temperature- Blood
  • 3057       Temperature- Tympanic
  • 3058       Temperature- Bladder
  • 3059       Temperature- Nasopharyngeal
  • 3060       Temperature- Axillary
  • 3061       Temperature- Rectal
  • 3062       Temperature- Myocardial
  • 3533      Temperature Route
  • 50191    Monitoring- Temperature Probe Placed
  • 50192    Monitoring- Temperature Probe Location/Type

Warming Method

  • 50138    Patient Warming Method- Convective Warmer
  • 50320    Warming Attempts- Warm Room
  • 50321    Warming Attempts- Convective Warmer
  • 50322    Warming Attempts- Warm Blanket
  • 50323    Warming Attempts- Radiant Heaters
  • 50324    Warming Attempts- Fluid Warmer
  • 50325    Warming Attempts- Warmer or blankets location detail


  • 50127    Intubation Extubated Awake or Deep
  • 50145    Laryngeal Mask Airway removed Deep or Awake
  • 50202    Emergence- Patient Extubated
MPOG Phenotypes Used
  1. Carpenter L, Baysinger CL. Maintaining perioperative normothermia in the patient undergoing cesarean delivery. Obstetrical & gynecological survey. 2012;67(7):436-446.
  2. Horn EP, Schroeder F, Gottschalk A, et al. Active warming during cesarean delivery. Anesthesia and analgesia. 2002;94(2):409-414, table of contents.
  3. Insler SR, Sessler DI. Perioperative thermoregulation and temperature monitoring. Anesthesiology clinics. 2006;24(4):823-837.
  4. Kim P, Taghon T, Fetzer M, Tobias JD. Perioperative hypothermia in the pediatric population: a quality improvement project. American journal of medical quality : the official journal of the American College of Medical Quality. 2013;28(5):400-406.
  5. Madrid E, Urrutia G, Roque i Figuls M, et al. Active body surface warming systems for preventing complications caused by inadvertent perioperative hypothermia in adults. The Cochrane database of systematic reviews. 2016;4:Cd009016.
  6. Sessler DI. Temperature monitoring and perioperative thermoregulation. Anesthesiology. 2008;109(2):318-338.
  7. Sun Z, Honar H, Sessler DI, et al. Intraoperative core temperature patterns, transfusion requirement, and hospital duration in patients warmed with forced air. Anesthesiology. 2015;122(2):276-285.


Measure Authors
Measure Author Institution
 Nirav Shah, MD  University of Michigan
 Jaime Osborne, RN  University of Michigan
 Kate Buehler, MS, RN  University of Michigan
 Meridith Wade, MSN, RN  University of Michigan
 Jay Jeong  University of Michigan
 Sachin Kheterpal, MD  University of Michigan
 MPOG Quality Committee  


Measure Reviewer(s)
Next Review: 2025
 Date Reviewed  Reviewer  Institution  Summary  QC Vote

 Sunny Chiao, MD

 Aisha Qazi, MD

 University of Virginia

 Corewell East - Troy


  No Change

Published Date: 06/2016
 Date  Criteria  Revision
 10/19/2023  Exclusion

 Modified case end algorithm updated to use latest time for extubation/LMA removal.

 Removed MRI exclusion

 Added Diagnostic Imaging exclusion

 4/11/2023  Multiple

 Exclusion: Case duration algorithm updated 

 Success: Updated end time from Case End phenotype to Patient out of room 


 Exclusion  Modified to use Obstetric Anesthesia Technique phenotype; Cases now invalid if case end < case start
 12/2/2019  Exclusion   Modified to use Anesthesia CPTs for Measures phenotype instead of Primary Anesthesia CPT phenotype
  6/1/2016    Initial Publication