CLINICAL CARE The Pupillary Response in Traumatic Brain Injury: A Guide for Trauma Nurses Andrea Adoni, BSN, RN, CCRN, CEN, EMT or stationary object (19%), and assaults (11%).3 Injuries to Molly McNett, PhD(c), MSN, RN the brain are classified as focal, such as cerebral contusions, lacerations, and hematomas/hemorrhages, or diffuse, which include concussions and diffuse axonal injuries.4 Because the signs and symptoms of patients who have sus- ■ ABSTRACT tained TBIs may change quickly and evidence of deteriora- Traumatic brain injuries (TBIs) affect more than 1.4 mil- tion may be subtle, trauma nurses must be adept at lion Americans annually. Trauma nurses caring for these performing astute neurologic assessments. patients routinely perform serial neurologic assessments, A key component of any neurologic assessment is the including pupillary examinations. While trauma nurses pupillary examination.4 Trauma nurses at all levels of are likely familiar with basic components of the pupil- care routinely perform pupillary assessments on patients lary examination, some confusion about more specific and are likely to be familiar with the basic components aspects of the examination and the physiologic basis of of the pupillary examination. However, some confusion the pupillary response may still remain, particularly as it may still remain about more specific aspects of the exam- pertains to patients with TBI. Therefore, the purpose of ination and the physiologic basis of the pupillary this article is to identify the key components of a pupil- response, particularly as it pertains to patients who have lary examination and its associated physiologic sustained TBIs. Therefore, the purpose of this article is to response. A case study is provided to illustrate the appli- identify the key components of the pupillary examina- cation of this information among patients with TBI. tion, explain the physiologic basis of the pupillary response, and illustrate the application of this informa- ■ KEY WORDS tion in patients with TBI through a case study. Brain injury, Pupil, Trauma ■ CASE STUDY raumatic brain injury (TBI) affects more than 1.4 mil- An 18-year-old woman was a restrained driver of a vehi- Tlion Americans annually.1 These injuries, defined as a cle that was T-boned (lateral) at a high speed on the dri- blow or penetrating injury to the head that disrupts normal ver’s side of the car. The car subsequently rolled over onto brain function,2 occur as a result of falls (28%), motor its roof. Emergency medical services arrived to find the vehicle crashes (20%), being struck by or against a moving victim conscious but with a Glasgow Coma Scale (GCS) Score of 13 (Table 1). The victim’s pupils were noted to be equal and reactive. The victim’s level of consciousness continued to deteriorate while the emergency medical Andrea Adoni, BSN, RN, CCRN, CEN, EMT, is Flight Nurse Specialist, Cleveland Metro LifeFlight; MetroHealth Medical services worked to free her from the wreckage. She Center, and ACNP student, Frances Payne Bolton School of arrived at the regional emergency department after Nursing, Case Western Reserve University; and Molly McNett, 40-minute extrication with a GCS Score of 8: she was given MSN, RN, is Research Coordinator, Department of Nursing a 2 for opens eyes to painful stimuli, a 2 for unintelligible Research, MetroHealth Medical Center, Cleveland, Ohio. verbal response, and a 4 for withdraws to pain. Her Corresponding Author: Andrea Adoni, BSN, RN, CCRN, CEN, EMT, Cleveland Metro Lifeflight Office, 4th Floor pupils were now unequal. The right pupil measured 5 mm Hamann, MetroHealth Medical Center, 2500 MetroHealth Dr, and was nonreactive to a direct light, whereas her left Cleveland, OH 44109 ([email protected]). pupil measured 2 mm and displayed a sluggish reaction October–December 2007 Journal of Trauma Nursing • Volume 14, Number 4 191 ■ IDENTIFYING TBI TABLE 1 Identifying an acute brain injury in patients with trauma requires serial neurologic examinations, including pupil- lary assessments, a CT scan, and possibly a magnetic reso- The Glasgow nance imaging. As depicted in the case study, evidence of TBI may be present in the initial neurologic examination Coma Scale performed at the scene. Victims may have altered GCS scores or impaired level of consciousness ranging from sub- Eye opening tle to severe. The initial pupillary examinations may appear Spontaneous 4 benign, and pupillary changes may not surface until hours after the occurrence of the injury. Performing serial neuro- Response to verbal command 3 logic examinations, including pupillary assessments, aids in Response to pain 2 identifying subtle changes in a patient’s neurologic status. No response 1 These subtle changes can indicate the presence of TBI and/or an acute deterioration in a patient’s condition.4 The Best verbal response presence of TBI is confirmed with a CT and/or a magnetic Oriented 5 resonance imaging once a patient arrives in a healthcare facility. The CT scan can quickly aid in differentiating Confused 4 between a focal and a diffuse brain injury. Inappropriate words 3 Subdural hematomas are one type of focal brain injury 4 Incomprehensible sounds 2 occurring in approximately 30% of patients with TBI. An acute subdural hematoma occurs usually after a decelera- No verbal response 1 tion injury in which cerebral veins rupture because of 5 Best motor response either a linear or rotational shearing force. Rupture of these vessels causes bleeding into the subdural space. This Obeys commands 6 bleeding may exert additional pressure onto the surround- Locales to pain 5 ing brain tissue, causing shifting of the tissue or mass effect. Because the subdural space is not limited by the cra- Withdraws to pain 4 nial sutures, this bleeding can potentially spread along the Flexion to pain 3 entire cerebral hemisphere.6 As the size of the bleed and Extension to pain 2 the mass effect on the brain increases, the patient’s neuro- logic status declines, and pupillary changes often appear. No motor response 1 As bleeding continues, the likelihood of a poor prognosis also increases: mortality rates as high as 50% have been reported among the patients who present with a subdural hematoma requiring immediate surgical evacuation.6 to direct light. She was noted to have a small forehead laceration with surrounding ecchymosis. She was ■ THE PUPILLARY EXAMINATION sedated, paralyzed, and intubated by the emergency The standard of care for any patient with TBI includes department staff to ensure airway protection. A comput- serial neurologic examinations. These examinations erized tomography (CT) scan of the patient’s head was include a pupillary assessment and are often performed performed, which revealed a large subdural hematoma. by trauma nurses at the scene, in the emergency depart- The patient’s neurologic status continued to deteriorate, ment, and in the acute and critical care units.7 Unlike and, therefore, the local air medical service was immedi- other components of the neurologic examination that ately dispatched to transport the patient to a level I require patients to be conscious, the pupillary examina- trauma center. She was transported to a level I trauma tion is one of the few neurologic signs that can be center for further evaluation of her head injury. Upon her assessed in an unconscious patient or in a patient receiv- arrival to the trauma center, her trauma evaluation was ing neuromuscular blocking agents and sedation. The completed, and she was transferred to the surgical inten- pupillary examination is a minimally invasive assessment, sive care unit. Her pupils were found nonreactive on her which provides valuable information about the severity initial trauma evaluation at the trauma center. In the sur- and progression of the brain injury, as well as brainstem gical intensive care unit, a neurosurgical consultation for function. Thus, it is important for trauma nurses to per- the treatment of an acute subdural hematoma and possi- form pupillary examinations thoroughly and understand ble surgical evacuation was obtained. the physiologic basis of the pupillary response. 192 Journal of Trauma Nursing • Volume 14, Number 4 October–December 2007 When performing a pupillary examination in patients A complete pupillary reactivity examination also with TBI, a trauma nurse should make the conscious includes assessment of the consensual pupillary response patient focus on a distant object straight ahead. In the and accommodation. The consensual pupillary response comatose patient, pupils are assessed per the position is the constriction that normally occurs in a pupil when they are found in. A pupil assessment should include the light is shown into the opposite eye.6 Because of this examination of size and equality of pupils, pupillary response, the trauma nurse should wait for several sec- shape, and reactivity to light. onds before assessing pupillary light reflex in the second eye, as that pupil may be temporarily constricted. Pupil Size and Equality Accommodation is the constriction of pupils that occurs Pupil size is reported as the width or diameter of each when a conscious patient is focusing on a close object. pupil in millimeters. A standardized pupil gauge should Pupils should normally constrict bilaterally when an be used to report the pupil size in millimeters. The use of object is held within 4 to 6 inches of a patient’s nose.6 this gauge aids in decreasing subjectivity, particularly when serial assessments are performed. The normal ■