13. thoracic surgery 1 - trauma & chest wall disease

describe basic steps of MILA chest tube placement

• assistant pulls skin cranially

• penetrate chest wall by over-the-needle catheter

  • enter around 7th or 8th rib space, somewhat dorsally

• pass j-wire guide through catheter

• remove catheter, leaving guidewire in place

• advance chest tube over j-wire guide

• remove guidewire and release skin

non-MILA thoracostomy tube placement

• skin incision — dorsal 1/3 of 10th or 11th IC space

• tunnel in SQ or under latissimus dorsi

  • limits tracking of air

• insert into chest through 7th or 8th IC space, mid-thorax

trocar thoracostomy tube placement

• catheter placed under skin

• raise catheter at least 45°; use non-dominant hand to prevent catheter from going too far into chest cavity

• once you’ve entered pleural space, catheter is advanced and trocar is removed

removal of thoracostomy tube

• usually maintained 12-24 hrs (longer for chronic disease / effusions)

• aspirate every hour (or more) until production slows and then increase duration

• remove once plateaus at an “acceptable” level

  • (fluid will be produced due to tube inflammation; 1-2 mL/kg/hr)

what does negative pressure indicate?

• pleural space evacuated

• valve not open

• tube kinked

• tube obstructed with clots or fibrin

• fenestrations within subcutaneous space (tube has backed out into SQ space)

**troubleshoot before pulling the tube!

indications for pleuralport

• chronic pleural effusions (e.g. chylothorax)

• can go home with it

• reduces risks associated with multiple thoracocenteses & short-term thoracostomy tube (pain, dislodgement, infection)

pleuralport installation

• port is sutured to epaxial musculature, while tube is fed into the thoracic cavity under the latissimus dorsi muscle

• port is then drained using a special huber needle (↓ damage to port over time)

thoracic trauma causes

• blunt force trauma / high impact

  • motor vehicle

  • fall from height (“high-rise” injuries)

• bite wounds

• weapons (knives/gun shot)

• male dogs over-represented (roaming behavior)

thoacic trauma — associated problems

• impaired respiratory function

  • pulmonary contusions (bruising) or lacerations

  • pleural fluid/air (hemo- or pneumothorax)

  • rib fractures/flail chest

• cardiovascular compromise

  • hypovolemia ± hypoxemia

  • myocardial contusion

  • arrhythmias

• extensive soft tissue damage

  • prone to tissue necrosis & infection

• diaphragmatic hernia unlikely

  • typically result of abdominal trauma, NOT thoracic trauma

stabilization of thoracic trauma patient

1. ABCs (airway, breathing, circulation)

2. supplemental oxygen (V/Q mismatch — low V/Q)

   • hemorrhage & fluid leakage into interstitial space

3. IV catheter: restore circulating blood volume

4. aggressive pain management (pain contributes to poor respiratory function)

   • opioids

   • local anesthetics

     • intercostal or intrathoracic bupivacaine

5. prophylactic antibiotics (amoxicillin-clavulanic acid)

6. thoracic drains (thoracostomy tube)

7. intubation and ventilator in some cases

   • persistent hypoxemia or respiratory effort despite oxygen support

stabilization often takes place before or concurrent with diagnostics

thoracic trauma — diagnostics

• PE, blood pressure

• ECG: ventricular arrhythmias common

  • cardiac contusions

• pulse oximetry

• arterial blood gases

• T-FAST

  • pulmonary contusions

  • pneumothorax or pleural effusion

• diagnostic bilateral thoracocentesis (when U/S not available)

• thoracic radiographs and/or CT scan once stable

• CBC, biochem panel, lactate

  • evaluate for concurrent injuries & extent of tissue damage

things to look for using T-FAST — thoracic trauma

• sensitive for pleural and pericardial effusion

• glide sign

  • indicates pleural contact

  • lack of glide sign indicates pneumothorax (in that location)

    • should evaluate both hemithoraces in multiple locations

• pulmonary injury & contusions

• B lines

  • white, vertical, narrow-broad bands perpendicular to lung surface

  • move in sync with lung sliding

  • can indicate pneumonia, edema, contusions, atelectasis

• shred signs (contusions)

  • consolidated lung next to air filled lung

  • deep border of consolidated lung appears “shredded”

things to look for on thoracic radiographs — thoracic trauma

• rib fractures

• pulmonary contusions

• pneumothorax

• pleural effusion

• pneumomediastinum

• atelectasis

• diaphragmatic hernia

• sternal fractures

• pericardial effusion

**perform when patient is stable!

what is “flail” (floating) chest?

• fractures of multiple ribs → freely moveable segment of thoracic wall

• asynchronous / paradoxical movement of chest wall during respiration

• results from extreme external force

• limited lung expansion

• increased respiratory rate and effort

  • dyspnea thought to be due to concurrent injuries (contusions, pain, etc.) → animals can do great when removing ribs for non-traumatic cases

• however, concurrent pneumothorax and pulmonary contusions common

when is surgery for thoracic trauma indicated?

• penetrating trauma

• thoracic organs visible

• severe thoracic trauma, lung lobe laceration, pneumothorax

• flail chest with respiratory compromise

more likely to be needed in smaller dogs (size of animal vs. force of trauma)

causes of hemothorax

• can be due to direct trauma & associated hemorrhage

• may also be due to acute traumatic coagulopathy (ATC)

  • delayed onset bleeding

  • depletion of thrombin & fibrinogen and release of tissue plasminogen activator (anticoagulant)

  • unlike DIC, platelets are spared and there is a lack of microthrombi development

  • clotting times (PT/aPTT) platelet counts, vWF often normal

  • may be detected with thromboelastography assay (TEG)

**hemothorax alone is not cause for surgery; should manage medically with blood products & medications

what is tranexamic acid (Txa)?

• antifibrinolytic agent

  • inhibits plasminogen activation

• blocks breakdown of blood clots

• may cause vomiting (treat with maropitant)

general thoracic trauma surgery

• subdermal tissue, muscle, and internal organs often injured without skin defects

• start by clipping affected area, evaluating wounds, and applying sterile bandages

• patient should be intubated as lungs may be exposed beneath skin

• lavage and clean wounds

• debride necrotic tissue

• culture wound

thoracic trauma surgery — rib fractures

• most don’t require repair

• indications for treatment

  • devitalized (remove)

  • laceration of underlying lungs

  • functional defect (flail/floating chest)

• repair

  • kirschner wires or intramedullary pins

  • suture to reappose ends

• stabilize local soft tissue with suture, muscle flaps, or mesh

goal of thoracic wall reconstruction

• need barrier between environment and lungs to re-establish negative pressure

  • more important than restoring perfect anatomy

• reconstruct thoracic wall if possible

  • apposition of remaining ribs

  • local muscle and skin flaps

  • placement of mesh

thoracic trauma surgery aftercare

• empty wound drains as needed

• evacuate chest tube q1-4hrs

• aggressive pain management

• oxygen or ventilator support as needed

• antibiotics — adjust if needed based on culture

• monitor for bleeding, protein loss, etc.

  • blood products, plasma, etc. may be indicated

• additional wound care and debridement may be necessary

types of thoracic wall neoplasias

• include primary rib & sternum tumors, invading soft tissue tumors, metastasis from other tumors

• most are malignant

  • osteosarcoma

    • osteoblastic, chondroblastic, undifferentiated

  • chondrosarcoma

  • fibrosarcoma & hemangiosarcoma uncommon

  • cutaneous or subcutaneous mast cell tumors

thoracic wall neoplasia signalment

older, large breed dogs (golden retrievers, labradors, etc.)

thoracic wall neoplasia — initial diagnostics

• plain radiographs — lytic and/or blastic (will also reveal metastasis for staging)

• FNA = low yield (sarcoma cells tend to stick together and not exfoliate well)

• biopsy — tru-cut vs. surgical approach

  • do not just do punch biopsy — will likely just retrieve normal tissue

• ± ultrasound (many are mineralized)

thoracic wall neoplasia — staging

• often referred at this point

• hematology & serum biochemistry

  • ALP prognostic (related to bone pathology)

• lymph node aspirates?

  • draining LN of thoracic wall is sternal lymph node (dorsal to 2nd or 3rd sternebra)

• CT scan

  • evaluate for pulmonary metastasis and draining lymph nodes (sternal lymph node)

curative intent surgery for thoracic wall neoplasia

• invasive! — client communication

• rib tumors

  • at least 1 rib cranial & caudal to lesion

  • > 3 cm from tumor margins

  • entire affected rib (intramedullary spread common)

• sternal tumors

  • at least 1 sternebra cranial & caudal

  • > 3 cm from tumor margins

what is pectus excavatum?

• rare congenital anomaly; more common in cats than dogs

• defective osteogenesis and chondrogenesis → lack of skeletal rigidity

• dorsal deviation of sternebrae resulting in loss of thoracic volume, pulmonary ± cardiac compromise

pectus excavatum treatment

• treat if clinical

• ideally performed < 4 months of age (before skeletal maturation)

• external and internal fixation options reported

• thermoplastic splints are lightweight

• good outcomes reported when splint maintained for at least 4 weeks

• potential complications reported: skin sores, pneumothorax, hemothorax, pulmonary edema, recurrence