Measure ID

Percentage of patients, regardless of age, who undergo surgical or therapeutic procedures under general or neuraxial anesthesia of 60 minutes duration or longer for whom a body temperature was less than 36 degrees Celsius (or 96.8 degrees Fahrenheit) recorded within the 30 minutes immediately before or the 15 minutes immediately after anesthesia end time

Measure Type

Perioperative hypothermia is defined as a core temperature less than 36 degrees Celsius by both the National Institute of Health and Clinical Excellence and the American Heart Association.1,2 It is not uncommon for a patient’s core temperature to drop during surgery due to anesthetic induced peripheral vasodilation, exposure of skin during the surgical prep or impaired heat distribution. Pediatric patients are more likely to develop perioperative hypothermia due to a high surface area to weight ratio, minimal subcutaneous fat and inability to regulate their own temperature.3 Perioperative hypothermia can result in multiple adverse effects including surgical site infections, cardiovascular events, impaired wound healing and increased hospital length of stay. Such adverse effects are prevented through maintenance of normothermia intraoperatively.4-9

Measure Time Period

All patients, who undergo General or Neuraxial  anesthesia of 60 minutes duration or longer

  • ASA 5 & 6
  • Cases < 60 minutes duration between anesthesia start and anesthesia end.
  • Obstetric Non-Operative Procedures (CPT: 01958)
  • Labor Epidurals (as determined by the MPOG 'Obstetric Anesthesia Type' Phenotype results 'Labor Epidural' and 'Conversion (Labor Epidural Portion)')
  • MAC cases as defined by Anesthesia Technique: General value code < 1
  • Burn Cases (CPT: 01953)
  • Procedure Type: MRI
  • Open Cardiac surgery as defined by Procedure Type: Cardiac
  • Cases with an intraoperative note mapped to intentional hypothermia (MPOG concept: 50037)
  • Emergency cases (MPOG concepts: 70142 or 515)
  • Invalid cases where Measure End results prior to Measure Start
Success Criteria

At least one body temperature measurement equal to or greater than 36 degrees Celsius (or 96.8 degrees Fahrenheit) achieved within the 30 minutes immediately before or the 15 minutes immediately after anesthesia end time. Please note this outcome measure is expressed as an inverse measure, where a lower score means better performance. 

Other Measure Details

Temperature documented in within the postop vital sign note in the anesthetic record or temperatures documented and mapped to the temperature physiologic concepts are acceptable sources for this measure. Conversion from F to C:    F=32 +9/5 (°C)

For sites that do not contribute PACU data to ASPIRE, this measure will only capture data documented by the anesthesia provider on the intraoperative anesthetic record.

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
Risk Adjustment

Not applicable.

Provider Attribution

Provider present for longest duration of the case per staff role. See ‘Other Measure Build Details’ section of this specification to view the algorithm used for determining case duration.

In the event that two or more providers in the same class are signed in for the same duration, all providers signed in for the longest duration will be attributed.

MPOG Concept Used
  • 3031      Temperature- Temporal Artery
  • 3050      Temp 1- Unspecified Site
  • 3051      Temp 2- Unspecified Site
  • 3052      Temp 1- Monitoring Site
  • 3053      Temp 2- Monitoring Site
  • 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
  • 50174    Postoperative Vital Signs
  • 50037    Intentional hypothermia
  • 70142    Assessment and Plan - Emergent Status
  1. Fleisher LA, Fleischmann KE, Auerbach AD, et al. 2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery: a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines. Journal of the American College of Cardiology. 2014;64(22):e77-137.
  2. National Collaborating Centre for N, Supportive C. National Institute for Health and Clinical Excellence: Guidance. The Management of Inadvertent Perioperative Hypothermia in Adults. London: Royal College of Nursing (UK)National Collaborating Centre for Nursing and Supportive Care.; 2008.
  3. 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.
  4. Sessler DI. Temperature monitoring and perioperative thermoregulation. Anesthesiology. 2008;109(2):318-338.
  5. 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.
  6. Carpenter L, Baysinger CL. Maintaining perioperative normothermia in the patient undergoing cesarean delivery. Obstetrical & gynecological survey. 2012;67(7):436-446.
  7. Insler SR, Sessler DI. Perioperative thermoregulation and temperature monitoring. Anesthesiology clinics. 2006;24(4):823-837.
  8. Horn EP, Schroeder F, Gottschalk A, et al. Active warming during cesarean delivery. Anesthesia and analgesia. 2002;94(2):409-414, table of contents.
  9. Yi J, Liang H, Song R, Xia H, Huang Y. Maintaining intraoperative normothermia reduces blood loss in patients undergoing major operations: a pilot randomized controlled clinical trial. BMC anesthesiology. 2018;18(1):126.
Measure Reviewer(s)
Next Review: 2024
 Date Reviewed  Reviewer  Institution  Summary  QC Vote

 Simon Tom

 Vikas O'Reilly Shah

 NYU Langone

 Seattle Children's


  No Change

Published Date: 04/2017
 Date  Criteria  Revision
09/13/2022  Exclusion  Modified MAC case exclusion to use Anesthesia Technique General and Neuraxial value < 1
06/10/2021  Flagged  Cases where no temperature is documented postop = Flagged
03/25/2021  Exclusion   Modified to use Obstetric Anesthesia Technique phenotype; Cases now invalid if case end < case start