Page 409 - WSAVA2017
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WSVA7-0362
NEUROLOGY
SOTAL - HEAD TRAUMA - STEP BY STEP EVALUATION AND TREATMENT
S. Platt1
1College of Veterinary Medicine- University of Georgia, Small Animal Medicine & Surgery, ATHENS, USA
HEAD TRAUMA - STEP BY STEP EVALUATION AND TREATMENT
Simon R. Platt BVM&S MRCVS Dipl. ACVIM (Neurology) Dipl.ECVN
University of Georgia, Athens, GA. Srplatt@uga.edu
Systemic Assessment
Initial assessment should involve evaluation of the patient’s respiratory and cardiovascular system. An airway must be established if necessary through endotracheal intubation. Breathing patterns may be affected by thoracic trauma, but may also be secondary to brain injury. Auscultation of the thorax may detect pulmonary pathology or cardiac arrhythmias. Oxygen support should be given as necessary and mechanical or manual ventilation may be required with severe pulmonary injuries. Traumatic pneumothorax may require thoracocentesis or chest tube placement to allow
proper ventilation. The cardiovascular system should
be evaluated by monitoring heart rate, blood pressure, and electrocardiography. An electrocardiogram may demonstrate cardiac arrhythmias secondary to traumatic myocarditis, systemic shock, or brain injury. Arterial blood analysis and lactate concentrations may provide additional information regarding systemic perfusion and respiratory function.
Neurologic Assessment
Neurological assessment should be undertaken on any animal, which has experienced a trauma. Assessment of neurologic status in a patient after head trauma should initially be performed every 30 to 60 minutes. Frequent assessment allows for monitoring efficacy of treatment and early recognition of a deteriorating status. Primarily, neurological evaluation of the patient serves to determine whether there are neurological deficits suggesting structural neurological lesions, where the lesions are located (i.e., at least intracranial, spinal and peripheral nerve), and the severity of the lesion(s). Detection of
a spinal and or peripheral nerve (e.g., brachial plexus) lesion can impact on the prognosis of any patient with head trauma. Without any extracranial lesions, the prognosis associated with head trauma is dependent on the location and severity of the parenchymal lesions. The assessment should include evaluation of state of
consciousness, motor function and reflexes, pupil size and responsiveness, position and movement of the eyes, and breathing pattern. The evaluation of pupil and eye function is the most accurate manner in which brainstem function can be assessed and this is the most important part of the examination prognostically. A scoring system has been developed in veterinary patients to provide an objective assessment and allow for rational diagnostic and treatment decisions.
TREATMENTTreatment strategies should be directed toward both systemic and neurologic stabilization in an effort to minimize secondary damage. Several aspects of treatment exist. Systemic stabilization involves correction of systemic shock and respiratory abnormalities with fluid therapy and oxygen therapy/management of ventilation respectively. The second aspect of treatment involves measures to reduce elevations in intracranial pressure and cerebral metabolic rate. Finally, some animals require surgical intervention because of lack of improvement or a declining neurologic status.
Fluid Therapy
The goal of fluid therapy of the head trauma patient
is to restore a normovolemic state. It is deleterious to dehydrate an animal in an attempt to reduce cerebral oedema. Aggressive fluid therapy and systemic monitoring is required to ensure normovolemia to maintain adequate CPP. Crystalloid, hypertonic, and colloid fluids should be given concurrently to help restore and maintain blood volume following trauma. Crystalloids are usually given initially for the treatment of systemic shock. These balanced electrolyte solutions may be given at shock doses (90 ml/kg for dogs, 60 ml/kg for cats). Typically, it is recommended that the shock dose be given in fractions starting with one third to one fourth of the calculated volume, frequently reassessing the patient for normalisation of MABP, mentation and CVP
if monitored, and giving additional fractions if needed. Unfortunately, crystalloid solutions will extravasate into the interstitium within one hour of administration requiring additional fluid resuscitation. Hypertonic and colloid
fluid therapy can rapidly restore blood volume using low volume fluid resuscitation; additionally, colloids, remain
in the vasculature longer than crystalloid fluids. These fluids should be used with caution as without concurrent administration of crystalloid solutions, hypertonic and colloid solutions can lead to dehydration. Other benefits of hypertonic fluids include the ability to improve cardiac output, restore normovolemia, and reduce inflammation after trauma. Hypertonic saline may be preferred in hypovolemic, hypotensive patients with increased ICP.
Hypertonic saline improves cerebral perfusion pressure and blood flow by rapidly restoring intravascular blood
An Urban Experience
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