Cath Lab Digest

T o some degree, almost every person with an open wound experiences pain. The pain may occur during wound cleansing or debridement (noncyclic pain), during repeated treatments such as daily dressing changes or repositioning (cyclic wound pain), or during quiet time without manipulation (persistent pain).¹ The pain experience might even be one of anticipation; the anxiety of a painful event potentially is as disabling and as real as physical pain.

The manner of dealing with the pain and the condition varies with the individual, the circumstances, and the level of the tissue injury. Healthcare professionals are responsible for recognizing the person in pain, assessing the type of pain, and determining appropriate interventions for relieving/easing the pain.

Pain is the reaction to signals transmitted throughout the body but more importantly, pain is what the person says it is. It is an experience that cannot be separated from the patient’s mental state, environment, and cultural background. These factors can cause the brain to trigger or abolish the experience of pain, independent of what is occurring elsewhere in the body. When assessing pain, investigating relevant mental and environmental factors is critical.²

The pain experience is dynamic and variable and has been categorized in different ways. Acute pain is described as an identified event that resolves in minutes, hours, days or weeks. Acute pain is usually nociceptive — nociceptive (from the word noxious meaning harmful) pain is caused by an injury or disease outside the nervous system. Nociceptors are specialized nerve endings in skin and deeper tissue. The pain may originate from direct nerve stimulation of the intact fibers.³ The pain is often an ongoing dull ache or pressure, rather than the sharper pain characteristic of neuropathic pain. The severity of pain usually correlates with the level of tissue damage. Nociceptive pain triggers a protective reflex (eg, to move your hand immediately if you touch a hot object). The pain is a symptom of injured or diseased tissue — when the underlying problem is cured, the pain usually goes away. Nociceptive pain is usually finite and responds well to treatment with opioids.

With persistent (chronic) pain, the cause is not usually identified or may be multifactorial and often is of undetermined duration. The pain can be nociceptive and/or neuropathic. The nerves continue to send pain messages to the brain even though tissue damage has ceased.

Neuropathic pain is a form of chronic pain. Neuropathy is any functional and/or pathological change in the peripheral nervous system. The three types of neuropathy are sensory, motor, and autonomic. They may occur individually or combined. Neuropathic pain is caused by damage to nerve tissues/fibers and is often felt as a burning or stabbing pain (eg, the pain experienced with a pinched nerve). The pain is often chronic and does not respond well to opioids. Neuropathic pain may respond to antiseizure and antidepressant medications. Nerve irritation (burning and/or stinging pain) may respond to tricyclics (amitriptyline or nortriptyline). The shooting/stabbing pain of nerve damage responds well to anti-epileptic medication (eg, gabapentin).