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Performing this block requires ultrasound experience.
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Needle visualization plays a major role in achieving a successful block.
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Epidural spread can occur from a unilateral injection.
Indications
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Patients who undergo operative procedures of the chest and upper abdomen.
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Unilateral coverage as thoracotomies, cholecystectomy, mastectomies, and other urological procedures with preservation of the pulmonary functions.
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Inadequate or unsuccessful epidural placement where bilateral catheters are placed.
Contraindications
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Caution with populations using anticoagulation and antiplatelet therapy.
Sonoanatomy
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The thoracic paravertebral space is a small triangular space lateral to the vertebral column.
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Bounded posteriorly by superior costotransverse ligament, anteriorly by the parietal pleura, and superiorly and inferiorly by the adjacent head and neck of the adjacent rib.
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The paravertebral space can be scanned in both the transverse and paramedian approach.
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In the transverse approach (short access) the ultrasound probe is aligned in the space between the two adjacent ribs overlying the transverse process. In this approach the space can be identified between the external intercostal muscle and intercostal membrane superiorly, and parietal pleura inferiorly.
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In the paramedian approach (long access) the probe lies in the paramedian plane of the transverse process. The external intercostal muscle and costotransverse ligament lie between the transverse process and deeper to it is the parietal pleura. The area between is the paravertebral space.
Technique
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In the transverse approach, the linear ultrasound probe is aligned over the long axis of the rib. Identifying the transverse process medially and the intercostal muscles and deep to it is the parietal pleura (sliding sign) ( Fig. 47.1 ).
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The needle, 18-gauge Tuohy, is introduced in line with the linear ultrasound probe from lateral to medial under direct visualization. The needle tip ends in the paravertebral space deep to the costotransverse ligament and just above the parietal pleura where the local anesthetic is deposited. Then a 19-gauge paravertebral catheter is inserted thorough the Tuohy needle up to 5 cm beyond the length of the needle.
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Local anesthetic used is ropivacaine 0.2% (1mL/kg) bolus up to 10 mL followed by a continuous infusion (max 0.4 mg/kg/hour).
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