Inadvertent postoperative hypothermia prevention: Passive versus active warming methods

This Article is brought to you for free and open access by Journal of Perioperative Nursing. It has been accepted for inclusion in Journal of Perioperative Nursing by an authorized editor of Journal of Perioperative Nursing. Recommended Citation Watson, Jessica (2018) "Inadvertent postoperative hypothermia prevention: Passive versus active warming methods," Journal of Perioperative Nursing: Vol. 31 : Iss. 1 , Article 4. Available at: https://doi.org/10.26550/2209-1092.1025

ertent postoperative hypothermia prevention: Passive versus active warming methods active warming methods


Inadvertent postoperative hypothermia prevention: Passive versus Inadvertent postoperative hypothermia prevention: Passive versus active warming methods active warming methods
32A8319F646E68CB55948F624845A62210.26550/2209-1092.1025


Inadvertent postoperative hypothermia prevention: Passive versus active warming methods

Temperature management within the perioperative environment is an imperative component of and a standard of practice in providing effective patient safety and comfort.This literature review will explore the evidence surrounding the use of active and passive warming mechanisms in the prevention of postoperative hypothermia.Many studies have recognised the adverse consequences of inadv rtent postoperative hypothermia, hence the rapid advancement in education about and use of equipment and devices for its prevention.Evidence-based literature was reviewed to provide rationales and recommendations for strategies to prevent postoperative hypothermia.This literature review will potentially guide clinicians through the use of effective devices to allow for informed choices to provide appropriate patient care.

Inadvertent postoperative hypothermia (IPH) is defined as a core body temperature lower than 36˚ C. IPH usually occurs in response to general or regional anaesthesia and transpires due to the vasoconstriction mechanism responsible for maintaining temperature becoming inhibited on administration of anaesthetic agents.Not only is anaesthesia responsible for a 20 per cent reduction in metabolic heat production but also environmental factors such as the cold operating theatre, body exposure and lack of prewarming for flushing solutio

affect the
incidence of IPH 1 .Some authors have reported that the incidence of postoperative hypothermia morbidity can be as high as 50 to 90 per cent [2][3][4] .Perioperative nurses have a primary role in caring for and monitoring patients within the Post Anaesthesia Care Unit (PACU) and it is imperative that they gain increased knowledge of and understanding about the management of IPH to improve patient outcomes.


Background

Various studies have proven that IPH can lead to patients experiencing a variety of physiological changes.These changes can include cardiac arrhythmias leading to cardiac arrest, increased mortality 5 , infection and complications of the surgical wound 6 , prolonged bleeding 7 , and increased discomfort and shivering 8 .According to Giuliano and Hendricks 5 around 70 per cent of surgical patients will experience IPH.As a consequence of compli ations related to IPH, hospital stays may be prolonged resulting in increased treatment costs for surgical site infections (SSI), increased transfusion needs and extended PACU stays 9 .Temperature management therefore can be cost efficient; however, it is the PACU nurse's role to correctly identify and utilise appropriate warming strategies to provide the patie

with
safe and effective perioperative journey 10 .This literature review extensively critiqued and analysed the different way

of managing inadverten
postoperative hypothermia in the postoperative area.This review will help to identify the most cost-Peer-reviewed article effective and efficient strategies that ultimately will prevent and treat this common surgical complication while providing comfort to patients within the PACU.


Te ms

Terms used within this literature review include:

• core temperature - he temperature of the blood and internal organs

• normothermia -a temperature ange between 36.5 ˚C and 37.5 ˚C

• hypothermia -core temperature be ow 36 ˚C

• active warming -a process that transfers heat to a atient


Management strategies

A combined total of 2594 participants accumulated from 17 studies were included.Recommended prevention strategies to maintain or restore normothermia that have been identified in this review include:

• passive warming aimed at reducing heat loss via cotton blankets and surgical drapes

• administration of warm fluids both intravenously (IV) and via irrigation

•

ctive warming devices t
transfer heat to the patient via forced airwarming

• limiting skin exposure within low temperature operating theatres.

The interventions were then narrowed to studies that included:

• patients over the age of 18 years old that where given a general/ deep sedation or regional anaesthetic It should be noted that throughout this literature review reliability and accuracy of temperature measurement was questioned due to the wide range of measurement devices and routes used, along with variations in hypothermia definitions.Urrútia et al. 13 state that temperatur should be measured at the same site as there is a difference between sites.National Institute for Health and Care Excellence (NICE) guidelines 14 suggest patient temperature should be measured from a direct measur ment of core temperature using axilla, rectal, pulmonary artery catheter, urinary bladder or sublingual sites.In the postoperative phase the temperature should be taken on arrival to the PACU and every 15 minutes following until discharge to the ward.If the pat ent's temperature is below 36 ˚C, warming methods must be commenced until the patient is comfortable 14 .


Active warming methods

According to literature from Nieh and Su 7 there is a long history of using warming devices to prevent perioperative hypothermia.Among the studies reviewed there was great diversity in results as patients sometimes received more than

e warming i
tervention.FAW devices recommended by NICE guidelines 14 had favorable results in terms of reaching normothermia.Unsurprisingly FAW systems are the most commonly tested warming modality as they have a significantly greater association with reaching higher PACU core temperatures compared to non-warming systems 15 .

Other benefits associated with FAW systems include reduced cardiovascular complications, increased patient comfort, reduction of postoperative shivering and reduced incidence of bleeding complications and SSI 16 .

While FAW systems have been used in hospitals for more than 20 years and are proven to be provide significantly better outcomes, they still pose a risk to patients and staff through burn injuries, fire, monitor interference and surgical site contamination 17 .

The most common misuse of FAW systems, according to Wu 17 , is blowing warm air directly onto patients without using the blanket (known as 'hosing').However, the statistical risk of complications arising from FAW is unclear.John et al. 15 highlight the low risk of thermal injuries due to incorrect assembly or uneven temperature distribution within the blanket.The incidence of surgical site contamination was contested but not apparent and, following trials during colorectal and clean site surg