Objectives

1. Discuss the mechanisms of acute pain after trauma.

2. Evaluate posttraumatic pain modalities.

3. Describe the use of regional anesthesia for trauma patients including brachial plexus blocks, epidurals, and lower limb blocks.

INTRODUCTION

Pain is now considered the fifth vital sign. However, inadequate treatment of pain is common and can result in chronic pain syndromes in up to 69 percent of patients [1, 2]. This is more likely in the trauma setting, as pain often is the last priority in a patient who is hemodynamically unstable. Fortunately, this is changing. The joint commission on Accreditation of Healthcare Organizations recently stated that “unrelieved pain has physical and psychological effects” and that the patient's right to pain management should be respected and supported and that pain must be assessed in all patients [3].

Polytrauma involves injuries to multiple organs requiring emergent or urgent surgeries. The involvement of the central nervous system (CNS), cardiorespiratory system, as well as peripheral limbs results in significant pain to the patient. There is inadequate time to deal with such severe pain due to the need for lifesaving surgical procedures. The caregivers are often worried about masking clinical signs of major organ injury involving the CNS, abdomen, and chest viscera. Caregivers at the emergency site or in emergency rooms may be inadequately trained on the pain management modalities that are currently available. For a long time, regional blocks were not adequately exploited in the emergency rooms for pain management, but the trend is currently changing.

Objectives

1. Evaluate pain management modalities in the acutely injured patient.

2. Review the pharmacology of acetaminophen (paracetamol), nonsteroidal anti-inflammatory drugs, opioids, tramadol, local anesthetics, and ketamine in trauma patients.

3. Discuss the role of antidepressants, anticonvulsants, benzodiazepines, alpha 2 agonists, and entonox for acute pain in trauma.

4. Discuss the role of multimodal analgesia for trauma patients.

INTRODUCTION

The widely accepted definition of pain was developed by a taxonomy task force of the International Association for the Study of Pain: “Pain is an unpleasant sensory and emotional experience that is associated with actual or potential tissue damage or described in such terms” [1]. Managing pain can be challenging in most scenarios and providing adequate pain relief forms a vital part in the initial management of trauma. Inadequate analgesia in acute situations can have deleterious effects on the immune system, healing process, and autonomic activity and can lead to the development of a chronic pain state (see Chapter 35).

PATHOPHYSIOLOGY OF STRESS RESPONSE TO INJURY AND PAIN

Pain is a protective response. This reflex response has an effect on multiple systems in the body. These include exaggerated stress response, sleep deprivation, altered glucose homeostasis, increased sympathetic nervous system activation, and altered gastrointestinal, renal, and endocrine function. The stress response produced has effects on various organ systems additionally such as cardiovascular, immune, endocrine, and respiratory systems. Thus, the stress response to injury is a complex hormonal and neurologic phenomenon. In a trauma patient, the consequences of this response are multifactorial.