Page 97 - WSAVA2017
P. 97

E. Rudloff1
1Lakeshore Veterinary Specialists, Emergency and Critical Care, Glendale, USA
Elke Rudloff, DVM, DACVECC
Lakeshore Veterinary Specialists, Glendale, WI USA
Identifying the need for a thoracostomy tube requires identification of respiratory distress related to pleural space fluid/air. When mild to moderate pleural expansion is occurring, the patient is usually tachypneic with an asynchronous breathing pattern. If severe, the patient may appear anxious, “short of breath” (rapid, choppy breathing), and orthopneic. Emergent situations with large volume rapid expansion will require thoracostomy tube placement. Additional qualifiers for identifying the need for a thoracostomy tube include >/=3 treatments with thoracentesis in a 24-hour period, signs of cardiovascular instability, the need for a prolonged anesthetic procedure, and/or requiring positive pressure ventilation.
Supplemental oxygen is provided in any form tolerated by the patient in respiratory distress. A peripheral IV catheter is placed. In most cases, the patient with severe respiratory distress requires minimal restraint, but may benefit from administration of an anxiolytic
or sedative such as butorphanol (0.4 mg/kg IV/IM) or midazolam (0.25-0.5 mg/kg IV/IM). The cat may require staged interventions, starting with the administration of an anxiolytic or sedative first (IM), then placement of an IV catheter with periods of rest in an oxygen enriched environment.
Analgesia is administered by injection IV or locally prior
to making a skin incision. It is ideal to perform the tube placement procedures under controlled conditions,
with the patient orotracheally intubated with careful controlled assisted ventilation with oxygen. Injectable anesthesia is used in the form of etomidate, alfaxalone, propofol, alprazolam or ketamine, with a benzodiazepine. When laryngeal function is in question, propofol is
the anesthetic of choice to permit laryngeal function examination. A laryngoscope should be used to reduce the risk of improperly intubating the esophagus. A variety of orotracheal tube sizes should be readily available. In situations where the larynx cannot be visualized, but palpated, then the tube may be guided in digitally, or by inserting a polypropylene catheter
into the trachea over which an orotracheal tube is fed and the catheter removed. Proper placement of the orotracheal tube is ensured by: 1. visual inspection, 2. ausculting lung sounds bilaterally with a stethoscope during the administration of positive pressure ventilation, 3. evaluating the end-tidal CO2 (ETCO2)- if the patient is tracheally intubated and spontaneously or assist ventilating, then the ETCO2 should be >25 mmHg,
and if the ETCO2 is <5 mmHg, the tracheal tube may be misplaced in the esophagus or pharynx. Once airway patency has been established, then dedicated cardiorespiratory monitoring is initiated with pulse oximetry, ETCO2, ECG and indirect arterial blood pressure.
Once the decision has been made to place a tube, there must be a commitment to 24-hour direct monitoring or transfer to a 24-hour facility.
Thoracostomy Tube Placement
Thoracostomy tube placement is necessary when large volumes of fluid or air need to be removed from the pleural space, either in an intermittent or continuous manner. Conditions that warrant thoracostomy tube placement include hemothorax, pyothorax, chylothorax, postoperative thoracotomy, foreign body penetration, and pneumothorax. Pneumothorax can result from airway or lung rupture, thoracic wall trauma, esophageal trauma, and bulla tear.
Thoracostomy tube placement is performed through a mini-thoracotomy along the lateral thoracic wall using sterile technique. Large-bore tubes are used primarily with traumatic situations, when blood and/or air accumulations can be rapid and continuous aspiration is necessary to keep the lungs inflated. Choice of
tube should be based on the size of the patient and the material being evacuated. Tension pneumothorax should be managed with a large bore thoracostomy tube (approximately 1/2-2/3 the width of the intercostal space), and in rare cases require multiple tubes in a single hemithorax or bilaterally to overcome the volume leak from large airway tears. Patients with voluminous viscous effusions may also need large bore tubes placed to improve flow and reduce occlusion. Red rubber tubes tend to kink, cause more tissue irritation, and occlude more frequently than purpose-made polyvinyl chloride (PVC) or silicone thoracostomy tubes. Thoracostomy tubes should be placed and handled under strict asepsis. Fur should be clipped from the caudal border of the scapula to the last rib, and from dorsal to ventral midline. Skin should be surgically scrubbed, and the patient should be fully draped to prevent contamination of the tube and insertion site. Tubes should be pre-measured such that they should
An Urban Experience

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