While the goosebumps that appear when it’s cold out and go away once you’ve warmed back up don’t seem that harmful, shivering is a serious complication associated with temperature management (TTM).
But let’s back up a little bit – why does shivering occur in the first place?
Broadly speaking, shivering is an involuntary physiological response to changes between a sensed temperature and a patient’s normal setpoint. This is a musculoskeletal response that recruits a large number of motor neurons. Shivering starts in the core and spreads to extremities as it progresses.
Despite its sometimes violent presentation, it’s actually not an efficient way to increase core temperature, as most of the heat generated is by large leg muscles and gets dispersed into the environment. Which patients are most susceptible to shivering? Young people, those with increased muscle tone, and people with low magnesium levels. While shivering isn’t harmful in daily life, it poses a serious risk to neurologically impaired patients. Patients who shiver experience:
- Increased metabolic heat production (up to two to five times the normal rate), which impedes lowering patient temperature
- Additional cerebral metabolic stress
- Decreased cerebral oxygenation
- An uptick in metabolic demand, which increases both oxygen consumption and respiration up to two to three times above normal
- Elimination of any benefits of targeted temperature management.
Best Practices for Shivering Detection During TTM
While sometimes you can detect shivering in a patient through visual observation, there are several other ways to determine if shivering is taking place: 1) if there is “noise” occurring on the EKG tracing; and 2) if you feel any vibrations while palpating the neck, mandible, or pectoralis muscles of the patient. Ideally, patient shivering should be recorded using a standardized method, such as the BSAS (Bedside Shivering Assessment) scale. This scale has four levels, where the first is no shivering at all, the second is mild shivering in the neck or chest, the third is shivering in the neck or chest and less than two extremities, and the final level is intermittent shivering involving more than two extremities. Using a standard scale allows you to objectively track whether shivering interventions are effective and also helps during handoffs to other nurses.
The Best Shivering is No Shivering
It is best practice to prevent shivering from ever occurring. There are several methods you should consider. The first thing to remember is to be proactive, as the goal is to stop shivering before it starts. By monitoring a patient using the BSAS scale, you remain aware of changes in the patient, and hopefully keep him or her at the first level. After that, it’s beneficial to implement a stepwise approach which prioritizes the least sedating interventions and standardizes treatment.
For example, several counter-warming methods have proven effective in suppressing shivering. These include focal hand warming or warming the lower face along with inhaling heated or humidified air. One study even found that the addition of a forced air warming blanket (operating at 43⁰C) had positive effects in restricting the metabolic impact of shivering in neurologically impaired patients. The full approach to shivering management will vary based on the materials available in your unit, but every TTM protocol should include explicit shivering prevention measures.
Shivering is a serious complication for the neurologically impaired patient. However, there are methods available to mitigate this response. By monitoring the patient using the BSAS scale, making sure to be proactive and reactive, and having a clearly defined process to deal with shivering if it occurs, healthcare professionals can make sure that people usually think of as a simple reaction stays just that.
Check out DaiWai Olson’s “You Make Me Shiver” (or just download the slides) and “Leave it to Fever: Life Lessons for Neurogenic Fever Management” presented by Attune Medical’s Stephanie Slisz, BSN, RN.
Download the “Leave it to Fever” e-book, curated by Attune Medical’s Maria Gray, MA, RN and Melissa Naiman, PhD, EMT-B.