Pain in hospitalized patients has received increasing attention, however due to its
subjective nature, it has defied objective, quantitative measurements. If a patient is able
to communicate, pain may be assessed using standardized sentences, visual analog scales (VAS)
or plain numeric scales.
When a patient is unable to communicate, a method that would allow the caregiver to
continuously monitor patients' pain and alert the provider that the patient may be in pain
would be quite useful. The Pain Monitor uses a novel measurement technique of analyzing
changes in skin conductance that can be used in patients who are unable to provide a
subjective pain score. This study will compare the relationship between the measurements
taken by the PainMonitor and pain scores given by communicative patients to evaluate the
safety and efficacy of this monitor during planned, routine procedures.
Although pain must be assessed to be treated, it has been challenging to obtain consistent,
objective, and quantifiable measurements. The best methods currently available are subjective
scales communicated by the patient such as standardized sentences, visual analog scales
(VAS), or plain numeric scales.
When a patient is unable to communicate, methods used to monitor pain are inadequate. A
device that provides an objective assessment of pain in these patients would alert the
patient's caregivers that the patient may be in pain and analgesic treatment is indicated.
Various methods (Evans et al, 2013; Kantor, 2014; Isnardon, 2013) have been proposed to
monitor patients' reactions to nociceptive stimulation such as:
- changes in heart rate or blood pressure
- changes in microcirculation
- Auditory or somatosensory evoked potentials
All of these methods have been found lacking, mostly due to a lack of specificity for pain.
Pupillometry is not suitable for long periods of measurement and is sensitive to concomitant
treatment (e.g. opioids).
Galvanometry has the potential to provide specific information related to pain in patients
who are unable to communicate.
Since sweat glands are the only organs controlled solely by the sympathetic nervous system,
there is a reasonable chance that the use of galvanometry can provide a reliable means of
assessing pain. There are numerous papers on this topic; searching in PUBmed on the key words
"pain" and "skin conductance" results in more than 250 papers (selected references are
included in the list below). The PainMonitor system uses galvanometry to monitor changes in
skin conductance responses per sec mirroring the number of bursts in the skin sympathetic
nerves. This creates a warning for caregivers to assess the potential that the patient is in
- Patients between the ages of 18-89 years (inclusive), in an adult ICU
- Patients admitted to the ICU who are able to communicate their pain and anxiety using
- Patients must be cooperative and not agitated.
- Planned to have a potentially painful procedure
- Diagnosed neuropathic disease
- Use of neostigmine within the past 3 hours
- Use of regional anesthesia at the extremity where the device electrodes are placed