IntroductionPain is a subjective and objective indicator of the patient's comfort level. Maintaining a tolerable level of pain is essential for patients' overall recovery and outcome. As nurses we must assess the patient's pain level and respond appropriately. Many tools and theories have been developed and are used in different healthcare settings to help nurses and other disciplines better understand a patient suffering from pain. This article will provide a comprehensive analysis of the concept: Pain. Pain In the intensive care unit (ICU) many patients are mechanically ventilated and although they are mild to moderately sedated with medications, many times pain control is still an issue. In general, patients with higher positive end-expiratory pressure (PEEP) have increased pain on the ventilator compared to those with lower PEEP settings, and many of these patients' pain levels are not adequately managed due to vague indicators or the lack of nursing care. knowledge. Pain is unique to each individual and therefore a complex concept to define, evaluate and understand. Assessing the pain level of a patient who is unable to speak and possibly sedated can be a difficult task for nurses and therefore many tools have been developed to help make this assessment easier. Controlling the patient's pain is vital to a speedy recovery and it must be remembered that just because a patient cannot verbalize pain does not mean it is not absent. Pain in many care settings today is considered a fifth vital sign due to its enormous prevalence, however Zalon states that poor pain relief is well recorded and has been noted in nursing literature for over 20 years (Zalon, 1995). Even Florence Nightingale recognized pain and its importance... halfway through the paper...). However, the definition of pain includes and helps describe these other terms. Pain • An individualistic feeling of pain, discomfort, or suffering from one's works cited Campbell RJ (1996) Psychiatric Dictionary, 7th edition. Oxford University Press, Oxford, New York.Jensen, MP and Turk, D.C. (2014). Contributions of psychology to the understanding and treatment of people with chronic pain. American Psychologist, 69(2), 105-118. doi:10.1037/a0035641Lalloo, C., Kumbhare, D., Stinson, J., & Henry, J. (2014). Pain-QuILT: Clinical feasibility of a web-based visual pain assessment tool in adults with chronic pain. Journal of Internet Medical Research, 16(5), e127. doi:10.2196/jmir.3292Matsuzaki, K., & Upton, D. (2013). Wound treatment and pain management: a stressful time. International Journal of Wounds, 10(6), 638-644. doi:10.1111/j.1742-481X.2012.01038.x