1. Too Hot… Too Cold… Ahh, Just Right!
The Role of Intraoperative Fluid Warming in Hypothermia Prevention
Karen Moore
Certified Facilitator
As part of a Continuing Education Course sponsored by Ecolab

2. Speaker is employed by Ecolab Healthcare
Disclosure:
Speaker is employed by Ecolab Healthcare

3. Learner Objectives What is hypothermia
Phases of unplanned perioperative hypothermia
Common patient complications documented in the literature
Clinical and economic benefits of maintaining normothermia throughout a patient’s surgical experience
Role and best practices of intraoperative irrigation fluid warming in hypothermia prevention
Upon completion of this activity, you should be able to:
Define hypothermia.
Distinguish the phases of unplanned perioperative hypothermia.
Identify the common patient complications associated with unintended perioperative hypothermia as documented in the literature.
Describe the clinical and economic benefits of maintaining normothermia throughout a patient’s surgical experience.
Discuss the role of intraoperative irrigation fluid warming in hypothermia prevention.

4. Increasing pressure on hospitals to improve care
Professional Associations & Guidelines
Patient Advocacy Groups
Patient & Physician Satisfaction Metrics
In today’s environment, there are a lot of pressures on hospitals. Here are just a few of the major ones.
Reportable hospital quality metrics

5. What is Inadvertent Hypothermia?
Inadvertent hypothermia is caused by a drop in core body temperature.
During surgery, even a small drop in temperature (0.5°C) can be associated with negative clinical outcomes.
36oC
(96.8oF)
Question: What patient core temperature is defined as “mild inadvertent hypothermia”?

6. What factors can contribute to hypothermia?
Patient Status and Surgery Type
Physical status, pre-existing conditions
Major fluid or blood loss
Patient age and weight
Large volume of cool irrigation fluids
Patient
Open surgical site or body cavity
Three categories
1. Patient status and surgery type
Factors influenced by the OR staff
General Anesthesia and or Regional
Infusion of cold fluids or blood
General Anesthesia
Cold surgical environment
Factors Influenced by OR Staff
Effects of General Anesthesia 6

7. General anesthesia causes redistribution of core heat
Vasoconstricted
Periphery
31-35° C
Periphery
33-35° C
Core
36° C
Vasodilated
Our bodies are designed to protect the core. What are the first parts of the body to get cold when go outside in the winter… – your fingers and toes.
Describe redistribution.
When a patient receives anesthesia they become vasodilated.
This allows the warmer temperatures at the core to be redistributed to the periphery of the body.
This causes a drop in core temperature
Analogy: a building in winter that has closed doors and windows. Suddenly the windows are thrown open and the heat inside the building is allowed to go outside, dropping the internal temperature.
Using room-temperature irrigation adds an additional challenge to an already compromised patient.
D.I. Sessler, “Temperature Monitoring,”, Miller’s Anesthesia Textbook, ed. R.D. Miller (Elsevier Science, 1997), 7

8. Anesthesia widens the Inter-threshold Range
Temperatures below the inter-threshold range trigger the body’s natural warming responses
Normal Conditions
Inter-threshold Range
37.0o C
36.8o C
Under Anesthesia
Inter-threshold Range
37.0o C
33.0o C
Educate on the Interthreshold Range and how anesthesia affects that range.
Key message: Anesthesia affects the body’s response to the cold so the body’s natural responses don’t trigger until the body is already hypothermic.
Anesthesia inhibits the body’s natural reaction to the cold
A patient’s may respond as if he is warm even when hypothermic

9. from the start of general anesthesia
How quickly can inadvertent hypothermia occur
under general anesthesia?
Answer:
As little as
45 min
from the start of general anesthesia
Key messages:
The patient temperature drops quickly, 1oC in the first minutes, 1.6oC in the first hour
This temperature drop happens as soon as anesthesia is administered. The length of the procedure doesn’t correlate with time the patient is under general anesthesia. Even “short cases” can require anesthesia long enough for patient temperature to drop significantly. So, ask the audience, when does anesthesia start prior to the procedure. Describe what is physically happening to the patient under anesthesia prior to the start of the procedure —prepping, incision, etc. After about 30 minutes that patient’s core temperature drops 1 degree.
And what is that condition called…? (Hypothermia…)
Describe how administering cold (room temperature) fluid to the body could lower the temperature even further.
Maintaining normothermia used to be an issue for anesthesia, now it is a concern for all clinicians.
For reference, here’s the direct statement from AORN Recommended Practices for the Prevention of Unplanned Perioperative Hypothermia (2012 Edition, page 307)
“In the redistribution phase of unplanned hypothermia, a rapid shift of body heat from the body’s core to its periphery occurs, resulting in a core temperature drop of approximately 1.6oC (2.7oF) during the first hour after induction of anesthesia. The initial temperature drop of the redistribution phase is followed by a slow linear decrease phase during the second and subsequent hours of anesthesia, in which heat loss exceeds the body’s ability to metabolically produce heat. In this second phase, warming the patient can effectively limit further heat loss. After approximately three to five hours of anesthesia, the patient core temperature often plateaus and is characterized by a core body temperature that remains constant, even during prolonged surgery.”
Did you know…?
“All patients are at risk of hypothermia as the duration of anesthesia time increases” -AORN, 2012
1oC drop
D.I. Sessler, “Temperature Monitoring,”, Miller’s Anesthesia Textbook, ed. R.D. Miller (Elsevier Science, 1997), 9

10. Physics 101- Basic Science
Heat loss from a patient to the environment occurs by four mechanisms

11. How does hypothermia affect outcomes?
Poor Outcomes
Coagulation issues
Blood loss, transfusions
Blood pressure
Morbid cardiac events
Slower metabolism
Longer drug metabolism, LOS
1. Although hypothermia is a common perioperatuve problem it is not a benign one. The consequences are both physiological and psychological in nature and are far more serious than patients just “feeling uncomfortably cold”.
2.Research has demonstrated a clear link between hypothermia and serious adverse events including:
3.In a study of hip arthroplasty patients a decrease of 1.6 c or 2.9 F increased blood loss by 500ml
4.Coagulation cascade, platelet function and fibrinolysis
5. Surgical patients with cardiac disease and who are hypothermic are three times more likely to have adverse mycocardial outcomes – hypothermia elevates blood pressure, heart rate and plasma catecholamine, there is increased oxygen binding to haemoglobin which in turn reduces available oxygen for tissues
Epidural and spinal anesthesia each decrease the shivering and vasoconstriction threshold by about 0.6 C or 1.08 F. much of the regulation of core temperature actually depends on afferent thermal input from skin sensors in the legs. In a typical OR continious cold signals are generated from the periphery. In regional anesthesia however, thermal input is haltered throughout blocked regions. The resultant absence of cold signal s is interpreted centrally as relative leg warming in other words a regionally anesthesied patient percieves himself to be warm when he is really cold. Regional anesthesia is often accompanied by analgesics that impair thermoregulation even further.
Cooler temperature may impair neutrophil function. Reduction in cutaneous blood flow leads to subcuteanous tissue hypoxia and failure of the humoral immune response to reach targeted areas to fight infection. Hypothermia is associated with a three fold increase in SSI in colon resections and with a significant increase in infection in patients undergoing cholecystectomy.
Shivering
Discomfort, oxygen consumption
Immune response
3X SSI’s

12. How does hypothermia affect outcomes?
Incidence Rates
High Costs
SSI infection occurs in 4% of surgeries
60-90% of patients will become hypothermic without intervention
Length of stay from SSI’s can increase
4 – 14 days
$1100
Per SSI case
1. Although hypothermia is a common perioperatuve problem it is not a benign one. The consequences are both physiological and psychological in nature and are far more serious than patients just “feeling uncomfortably cold”.
2.Research has demonstrated a clear link between hypothermia and serious adverse events including:
3.In a study of hip arthroplasty patients a decrease of 1.6 c or 2.9 F increased blood loss by 500ml
4.Coagulation cascade, platelet function and fibrinolysis
5. Surgical patients with cardiac disease and who are hypothermic are three times more likely to have adverse mycocardial outcomes – hypothermia elevates blood pressure, heart rate and plasma catecholamine, there is increased oxygen binding to haemoglobin which in turn reduces available oxygen for tissues
Epidural and spinal anesthesia each decrease the shivering and vasoconstriction threshold by about 0.6 C or 1.08 F. much of the regulation of core temperature actually depends on afferent thermal input from skin sensors in the legs. In a typical OR continious cold signals are generated from the periphery. In regional anesthesia however, thermal input is haltered throughout blocked regions. The resultant absence of cold signal s is interpreted centrally as relative leg warming in other words a regionally anesthesied patient percieves himself to be warm when he is really cold. Regional anesthesia is often accompanied by analgesics that impair thermoregulation even further.
Cooler temperature may impair neutrophil function. Reduction in cutaneous blood flow leads to subcuteanous tissue hypoxia and failure of the humoral immune response to reach targeted areas to fight infection. Hypothermia is associated with a three fold increase in SSI in colon resections and with a significant increase in infection in patients undergoing cholecystectomy.
More Canadians die from adverse events in hospitals than from breast cancer, motor vehicle accidents and HIV combined.
$24 million
Estimated cost to treat preventable SSIs in Canada

13. Maintain Normothermia
SCIP INF-10 Measures
Published in 2010
Strict clinical guidelines around maintaining normothermia
Core temp must be above 36o C
Surgical Care Improvement Project: Released new guidelines in 2010 which were more strict than before. Now, according to these guidelines, a patient must remain normothermic (core body temperature above 36 deg C) 30 minutes before surgery until 15 minutes after surgery.
To maintain normothermia, patients may require pre-warming in the perioperative area, and comprehensive prevention measures during surgery.
Fun fact! Did you know…
One layer of warmed blankets can decrease heat loss by about 30%. Additional blankets however do not provide very much additional insulation.
30 min
Pre-surgery
Maintain Normothermia
15 min
Post-surgery

14. How does Hypothermia increase the risk of SSI?
Impairs neutrophil function (neutrophils are white blood cells - one of the first-responders of inflammatory cells to migrate towards the site of inflammation.)
Triggers vasoconstriction which reduces oxygen supply to tissue leading to tissue hypoxia

15. Reduction of SSI is one of six interventions targeted by Safer Healthcare Now
Intervention calls for the utilization of a series of protocols, including maintenance of patient normothermia, to reduce the prevalence of SSI
Success for patient normothemia is measured by the number of patients who are normothermic postoperatively. The goal is 95% or greater.
Further guidance states that patients should remain between 36.0°C and 38.0°C across the perioperative continuum (from pre-op through PACU)

16. Holistic Prevention Approach
1. Patient Assessment
2. Monitor core temperature
3. Implement prevention interventions
4. Educate care providers
5. Document patient care
6. Continuously improve quality
Focus on Prevention Interventions
OR Room Temperature
Pre-Warming
Active Patient Warming
Warm IV Fluids
Warm Irrigation Fluids
The AORN Recommended Practices for the Prevention of Unplanned Perioperative Hypothermia can be summarized by these 6 steps. We will especially focus on prevention interventions.
2012 Perioperative Standards and Recommended Practices, AORN, pages 16

17. How cold is your OR? OR Room Temperature
Operating rooms are usually kept cool
Patients are exposed to a cold environment
In non OR settings room air is exchanged approx 4 times per hour. In the typical OR room air exchanges occur approx 15 times per hour. This air movement makes the rooms seem subjectively cooler. Despite draping convection heat loss is considered the second most significant heat loss in the OR.
OR’s are typically kept below 23C (73.4 F) this is the temperature required to maintain normothermia for all but the shortest procedures
Surgeons are particularly vulnerable to warm OR’s because of the high level of stress during surgery and because they must wear multiple layers of clothing including sterile gowns, lead aprons. Physicians and other staff may perspire into the surgical wound if the temperature is not regulated. Warm temperature may also impair the OR personnel by decreasing their vigilance.
How cold is your OR?
How cold is your OR?

18. Warm Fluids Did you know… Examples
Warm IV Fluids
“Warming IV fluids should be considered only if large volumes (more than 2L) are being administered.”
“One unit of refrigerated blood or 1L of saline solution administered at room temperature decreases mean body temperature approximately 0.25oC in a 70kg patient.”
Did you know…
Examples
2012 Perioperative Standards and Recommended Practices, AORN, pages 18

19. AORN Recommended Practices
AORN recommends warm irrigation fluid for hypothermia prevention
Warm Irrigation Fluids
Warmed irrigation fluid near 37˚C should be used.”
AORN recommends verifying fluid temperature before use
“When using warmed irrigation solutions, the temperature of the solution should be measured with a thermometer at the point of use and verified before instillation. “
“The temperature of fluid … should be measured using a sterile thermometer or a commercially available intraoperative irrigation warming bath to ensure it does not exceed 37oC.”
2012 Perioperative Standards and Recommended Practices, AORN, pages 19

20. Fluid warming is like the story of Goldilocks…
Normothermia
Risk to Patient Safety
Risk of Hypothermia
Irrigation fluid should be at the “right” temperature.
Warming irrigation fluids to 36 C should always be used as a adjunct to decrease heat loss. In laproscopic surgery patients who had warmed irrigation fluids had higher core body temperature than those who had room air fluids. Of course the irrigation fluid temperature should always be checked others burns could occur.
Irrigation Temperature Range
… irrigation fluid should be at the “right” temperature

21. Irrigation Fluid Warming
Methods & Best Practices

22. Question: What % of procedures could benefit from warm irrigation fluid?
Surgical Area
Use warm irr fluid?
Answer:
General Surgery
Neuro Surgery
ENT
Plastic Surgery
Transplant Surgery
Cardiac/Thoracic Surgery
OB/GYN
Urology
Pediatrics
Ortho
Approximately
25-30%
Of surgical procedures benefit from the use of warm irrigation fluid
Each of these are opportunities to use WARM fluid.

23. Benefits of Irrigation Fluid consistently warmed to a safe temperature
Maintains patient normothermia
Reduces the risk of adverse clinical outcomes due to inadvertent hypothermia
Achieves goals of SCIP and other national collaboratives
Reaches TJC/CMS Core Measures and National Patient Safety Goals
Meets Medicare goals for reducing surgical site infections
Increases patient safety by reducing the risk of patient burns from hot solutions
Here’s a summary of the benefits of safe irrigation fluid warming.

24. Methods for Warming Irrigation Fluid1 2 3
Saline bottles in a cabinet warmer
Closed fluid warming system
Open basin active fluid warming system
Examples of commercially available methods for warming irrigation fluids

25. 1. Saline bottles in a cabinet warmer
Fluid Warming Cabinet Guidelines
Separate cabinets for blankets and saline solutions
Set solution cabinets at 110oF (43.3oC)
Routinely monitor cabinet temperatures
High temperature could pose patient safety risk
“ECRI Institute recommends that temperature settings on blanket warming cabinets be limited to 130oF (54oC) and that solution warming cabinets be limited to 110oF.
Temperatures above this level unnecessarily increase the risk of burns.”
ECRI Institute. Warming cabinets. Healthcare Risk Control. March 2010
“Warming cabinet temperature should be checked at regular intervals.”
2012 AORN Recommended Best Practices: Safe Environment of Care

26. Label saline bottles in a cabinet warmer
Fluid Warming Cabinet Guidelines
3 to 30 day bottle storage at elevated temperatures
Label bottles with expiration & discard after expiration
Do not put bottles back into cabinet after already warmed
Storing saline bottles in a warming cabinet is not really that simple. Because irrigation fluid is considered “medication” and because the saline has a limited lifespan once placed in the warmer, the solution bottles must be labeled and rotated. Here are some of the specific guidelines.
(Review the guidelines)
“Fluids kept in fluid warmers should be labeled with the date they should be removed or the date when they are placed in the warmer.” - AORN
2012 AORN Recommended Best Practices: Safe Environment of Care

27. Saline bottle cabinet warmers
Advantages
Relatively low cost, after capital purchase
Saline bottles are readily available
Considerations
Capital equipment cost, and space/location
Label and rotate saline inventory
Routinely monitor cabinet temperatures
Nursing staff must pull a bottle close to the time of use
Not efficient use of nursing resources
Remember…
It takes 8-10 hrs for bottles to warm up!
Example Cabinet 27

28. Patient Safety “Watch-Outs”
Saline composition can change to be more hypertonic (higher salt content) under extended heat
Cabinet warmers can “melt” the saline bottles under prolonged heat
Explain the watch outs. Talk about examples of actual experiences if possible.
Microwaves or autoclaves cannot guarantee a known or safe fluid temperature
(no microwaves or autoclaves)

29. Warm solution from a cabinet cools quickly
Question: How fast does 1 liter of 43oC fluid cool to body temp after being poured in a metal basin?
37 o C (Normal body temperature)
Even bottles from a warming cabinet cool down quickly over time. How long do you think it takes for a bottle of fluid to cool down to room temperature?
Explain the slide.
Answer: In less than 10 minutes - Approx 7 minutes. Also notice that temperatures too hot can risk injury, and too cold risk hypothermia. So there is about a 5 minute window when the fluid temperature is “just right.”
Test Parameters:
Ring stand
Metal basin
1L fluid
18oC room
Answer: About 7 minutes
Time window when fluid is “just right” is about 5-10 minutes
Ecolab Internal Testing

30. Warm solution from a cabinet cools quickly
Did you know…
“ 1L of saline solution administered at room temperature decreases mean body temperature approximately 0.25oC in a 70kg patient.”
Even bottles from a warming cabinet cool down quickly over time. How long do you think it takes for a bottle of fluid to cool down to room temperature?
Explain the slide.
Answer: In less than 10 minutes - Approx 7 minutes. Also notice that temperatures too hot can risk injury, and too cold risk hypothermia. So there is about a 5 minute window when the fluid temperature is “just right.”

31. 2. Closed Irrigation Fluid Warming System
Advantages
Set and validate the fluid temperature
May use standard IV bags
Irrigation fluid is under pressure
Rapid warming of fluid
Considerations
Typically for procedures requiring large fluid volumes or laparoscopic procedures
Single patient use tubing sets required
May require regular maintenance/calibration
Examples of closed irrigation fluid warming systems

32. 3. Open Irrigation Fluid Warming Systems
Advantages
Improves efficiency
Provides access to warm irrigation fluid within the sterile field
Eliminates labeling and rotating saline bottle inventory
Warms fluid quickly
Improves patient outcomes
Fluid maintained at optimal temperature to maintain normothermia
Reduces risk
Visible display confirms fluid temperature at point of instillation
Eliminates risk of patient burns
“The temperature of fluid on the sterile field should be measured using a sterile thermometer or a commercially available intraoperative irrigation warming bath to ensure it does not exceed 37oC.”
2012 AORN Recommended Best Practices: Safe Environment of Care 32

33. Using Open Irrigation Fluid Warming Systems1
Sterile drape
Single use, heavy-duty drape conforms to the inside of the basin and maintains a sterile field
Large volume basin plus pocket warmers
Flexibiltiy to meet various clinical procedures, disciplines, and protocols
Temperature control and visible display
Fluid is maintained at the set temperature, and easily monitored via an LED temperature display
Portable Stand
Caster wheels allow for easy transportation to the surgical table before and after the procedure 2 3 4
Considerations
Need to start the system during room set up
Need to inventory sterile drapes 33

34. RECAP: Did you know…
“Mild Inadvertent Hypothermia” is core body temp falling below 36oC
As little as a drop of 0.5oC is linked to negative outcomes
Patients can become hypothermic in as little as 45 minutes from the start of anesthesia
Hypothermia has been linked to a 3X increase in SSI
Normothermia improves outcomes including reduced blood loss, SSI’s, and length of stay
25-30% of surgeries may benefit from warm irrigation fluid

35. RECAP Part 2: Did you know…
Saline bottles must be labeled and rotated in warming cabinets due to shortened expiration date
110oF fluid cools down below body temp in less than 10 min after being poured into an open basin in the OR
Open fluid warming systems in the OR
Comprise a key element to hypothermia prevention
Provide immediate access to warm irrigation fluid within the sterile field
Eliminate labeling and rotating saline bottles
Maintain safe fluid temperatures and display fluid temperature at the time of use

36. Today we learned… Definition of inadvertent hypothermia
Contributing factors to inadvertent hypothermia
Common patient complications from clinical literature
Clinical and economic benefits of normothermia
Today we learned:
What is hypothermia?
What are the phases of unplanned perioperative hypothermia?
What are common patient complications associated with unintended perioperative hypothermia as documented in the literature?
What are some clinical and economic benefits of maintaining normothermia throughout a patient’s surgical experience?
What is the role of intraoperative irrigation fluid warming in hypothermia prevention?
What are some best practices associated with irrigation fluid warming?
Role and best practices of intraoperative irrigation fluid warming in hypothermia prevention

37. Thank you!