Effects of comfort warming on preoperative patients

AORN Journal, Sept, 2006 by Doreen Wagner, Michelle Byrne, Katharine Kolcaba

Temperature is an integral component of a patient s perception of well-being during the perioperative experience. Memories of thermal comfort or discomfort during surgery have an effect on a patient's overall satisfaction with surgical care. (13) Beginning in the preoperative phase of surgery, patients often remark that they feel cold. The most common nursing approach for addressing this patient discomfort is to cover the patient with warmed cotton blankets. After placing a warm blanket on a patient, the nurse often hears appreciative statements such as "I love getting these warm blankets before surgery. It really helps." The nurse recognizes an increase in overall patient comfort as a result of this warming intervention and, of equal importance, often perceives a decrease in patient anxiety immediately after the patient receives the blanket.

People respond holistically to complex stimuli, so the sensation of feeling cold produces discomfort and can trigger anxiety about

* the impending surgery,

* the anesthesia,

* expected pain, and

* being immobilized. (2)

Interventions to prevent or treat a patient's feeling of being cold, therefore, often have a positive effect on how the patient perceives other threats. Such interventions thereby may reduce a patient's anxiety. The problem addressed in this study is how nurses can intervene successfully to increase thermal comfort and decrease anxiety in the preoperative setting.

WARMING

Recent research has documented the therapeutic effects of warming preoperative patients. (1,4,5) Prewarming raises mean body temperature by increasing the energy content in the peripheral thermal compartment of the body. This is important because it is difficult to treat core hypothermia that occurs from an internal core-to-peripheral redistribution of body heat immediately after induction of general and regional anesthesia. (4-6) Anesthetic agents decrease the vasoconstriction threshold to a level below the current body temperature and thus open arteriovenous shunts. This redistribution is not a clear exchange of heat with the environment, but rather a flow of heat from the body's core to the periphery, thereby reducing the core temperature. (4-6) The redistribution of body heat can be prevented, however, with prewarming interventions in the preoperative setting. (1,4,5)

Traditionally, nurses have used warmed blankets to provide thermal comfort for patients in the preoperative setting. Unfortunately, the warmth from heated cotton blankets dissipates within 10 minutes. (7) Other passive and traditional approaches to providing thermal comfort include the use of insulative-type coverings such as reflective blankets, the placement of socks and head coverings on preoperative patients, and a manual increase in room temperature.

Warming a patient preoperatively is more effectively accomplished by using an active warming method. (4,5) Examples of active warming methods include the use of convective (ie, warmed air) warming blankets and fluid warming to maintain or increase a patient's body temperature. Active warming to the overall body and to localized areas also has been found to be an effective intervention for reducing patient's anxiety and complaints of pain in several recent studies. (8-11) Perioperative nurses frequently use preoperative warming both as a warming intervention and as a means of providing comfort. There are no published research reports, however, that focus on the benefit of preoperative warming as both a comfort intervention and as a method of decreasing patient anxiety.

ANXIETY

It has been recognized for more than 40 years that patients experience differing levels of anxiety when faced with impending surgery. (12-16) Preoperative anxiety is commonly associated with

* loss of independence or control,

* anesthesia concerns,

* unwanted diagnoses,

* postoperative pain, and

* fear of death.

Preoperative anxiety is reported to occur in 11% to 80% of adult patients. (15-19) Higher levels of anxiety have been linked to tachycardia, hypertension, arrhythmias, and increased levels of pain, which can affect the entire perioperative period of patient care. (19-21) Hormonal activity, known as the stress response, is widely believed to compromise recovery and includes an increase in circulating cortisol, adrenaline, noradrenaline, oxytocin, antidiuretic hormone, and prolactin. (21,22)

Anxiety was defined by Spielberger (23) as a group of behavioral expressions that can be divided into trait and state anxiety. Trait anxiety is a lifelong pattern of anxiety that is a personality characteristic. People with trait anxiety generally are nervous, hypersensitive to situational stimuli, and psychologically more reactive. State anxiety refers to acute and situationally driven episodes of anxiety that do not continue beyond the situation that triggers them. (19,23) An impending surgical experience is a good example of state anxiety. State anxiety is emotionally transitory and consists of feelings of tension, apprehension, and nervousness with heightened activity in the autonomic nervous system. This condition varies in intensity and can fluctuate during the specific experience. The definition of state anxiety used in this study is the unpleasant, self-aware feeling of tension and apprehension accompanied by arousal of the autonomic nervous system that is evoked in individuals who interpret a situation as personally threatening.