Effect of Cryoanalgesia on Reducing Unconscious Patients' Pain During Arterial Puncture

Pain is a disturbing experience for patients in intensive care units (ICUs). It has deleterious effects on patients' health as it can lead to adverse physiological and psychological consequences. Patients undergo a wide variety of painful, invasive procedures to maintain their lives, such as arterial puncture, tracheal intubation, suctioning, insertion or removal of a chest tube, and wound care. A recent study recorded that the prevalence of pain in the ICU is approximately 31%. Another study reported that pain occurred in 5.0% -31.1% of the patients during the first 6 days of their stay in the ICU. Moreover, other studies have illustrated that the severity of pain increases significantly from the baseline during clinical procedures.

Arterial blood gases analysis is frequently requested for critically ill patients to diagnose and manage their acid-base imbalances and respiratory problems. Insertion of arterial lines for the purpose of repeated sampling is not practiced in many places for lack of monitoring devices or lack of expertise. Thus, arterial blood sampling is inevitable for these patients. Arterial samples can be obtained from different arteries such as the radial, brachial, femoral, axillary, dorsalis pedis, and posterior tibial. Regardless which site is used, all of these arteries have a high nerve supply and require deep needle insertion to access them. Hence, this procedure is usually associated with significant pain.

Managing procedural pain is a challenging task in ICUs as most patients have a reduced level of consciousness (LOC). Thus, they cannot express their pain and suffering, which can be disturbing situations for them that have adverse effects on their health. Therefore, when caring for unconscious patients, procedural pain must be evaluated and alleviated to avoid its physiological complications and prevent more intense pain.

In ICUs, pain management is mainly dependent on pharmacological and nonpharmacological interventions. Several pharmacological interventions are available, such as opioids, non-opioids, and adjunct analgesics. Although these medications are effective and fast, they have many adverse effects, including tolerance, suppression of cough reflexes, respiratory depression, immunosuppression, increased ICU stay, and worse post-ICU patient outcomes, especially for mechanically ventilated patients. Therefore, pharmacological interventions should not be the only option for pain management.

Nonpharmacological interventions are also advocated to minimize patients' pain because they are simple, safe, noninvasive, and inexpensive. They include relaxation techniques, cognitive-behavioral strategies, and biophysical interventions such as massage, pressure, and cutaneous electrical nerve stimulation by heat or cold application.