Principles of Thoracic Surgery in Veterinary Medicine

Thoracotomy

surgical incision of the chest wall.

Intercostal / Lateral Thoracotomy

performed by incising between ribs.

Median Sternotomy

performed by splitting the sternum.

Pulmonary Lobectomy

removal of a lung lobe or a portion of a lung lobe.

Complete Lobectomy

removal of a lung lobe.

Partial Lobectomy

removal of a portion of a lung lobe.

Pneumonectomy

removal of all lung tissue on one side of the thoracic cavity.

Diagnostic biopsy

a procedure to obtain tissue samples for diagnosis.

Cardiovascular Surgery

surgery related to the heart and blood vessels.

Patent Ductus Arteriosus

a heart defect that affects blood flow.

Vascular Ring Anomalies

abnormalities in the blood vessels that can compress the esophagus or trachea.

Open Heart Procedures

surgical operations performed on the heart.

Neoplasia

the presence of a tumor or abnormal growth of tissue.

Pericardiectomy

surgical removal of the pericardium.

Emergency Stabilization

initial treatment to stabilize a patient in critical condition.

Flail Chest

a condition where multiple ribs are broken, causing respiratory impairment.

Acute Respiratory Impairment

sudden decrease in the ability to breathe effectively.

Thoracentesis

a procedure to remove fluid from the pleural space.

Oxygen Therapy

the administration of oxygen to improve oxygenation.

Blood gas analysis

a test that measures the levels of oxygen and carbon dioxide in the blood.

Pre-emptive Analgesia

administration of pain relief before a surgical procedure.

Intermittent Positive Pressure Ventilation (IPPV)

a method of mechanical ventilation that delivers breaths to a patient.

Premedication

medications given before anesthesia to prepare the patient.

Auscultation

Both sides of the chest cavity should be auscultated.

Endotracheal tube placement

Endotracheal tube palpated in the thoracic inlet to ensure proper placement.

End-tidal CO2 (EtCO2)

Confirmation should be made with the presence of end-tidal CO2 (EtCO2).

Intermittent positive pressure ventilation

Animals with open chest cavities (including those with diaphragmatic hernias) require intermittent positive pressure ventilation.

Arterial blood gas

Arterial blood gas is the gold standard for evaluation of ventilation and oxygenation.

Capnometry

Noninvasive technique for ventilation.

Pulse oximetry

Noninvasive technique for oxygenation.

Hypoventilation

EtCO2 - helpful in identifying potentially life-threatening situations such as hypoventilation.

Airway obstruction

EtCO2 - helpful in identifying potentially life-threatening situations such as airway obstruction.

Hypotension

EtCO2 - helpful in identifying potentially life-threatening situations such as hypotension.

Ventilator malfunctions

EtCO2 - helpful in identifying potentially life-threatening situations such as ventilator malfunctions.

Esophageal intubation

EtCO2 - helpful in identifying potentially life-threatening situations such as esophageal intubation.

Normal PaCO2

Normal PaCO2 = 35 to 45 mmHg.

Respiratory acidosis

PaCO2 >60 mm Hg indicates respiratory acidosis due to hypoventilation and would be an indication for IPPV.

Extubation

Extubation should not be rushed; patient should be awake and not overly sedated, respirations are adequate, and patient is comfortable prior to extubation.

Prophylactic antibiotics

Prophylactic antibiotics given at induction include Cefazolin 22 mg/kg IV.

Amoxicillin/sulbactam (Unasyn)

Amoxicillin/sulbactam (Unasyn) 30 mg/kg IV at induction; repeat once or twice at 90-minute to 2-hour intervals.

Therapeutic antibiotics

Therapeutic antibiotics should be initiated at the earliest sign of infection.

Leukocytosis

Leukocytosis is a sign for initiating therapeutic antibiotics.

Fever

Fever is a sign for initiating therapeutic antibiotics.

Ampicillin

Ampicillin is used until culture and sensitivity results are available.

Clindamycin

Clindamycin is used until culture and sensitivity results are available.

Enrofloxacin

Enrofloxacin is used until culture and sensitivity results are available.

Prophylactic antibiotic considerations

Appropriate use of prophylactic antibiotics depends on length of surgery, type of surgery, immune status, and underlying disease process.

Debilitated animals

Debilitated animals undergoing thoracotomy for removal of large neoplastic lesions are likely to benefit from prophylactic antibiotic therapy.

Thoracostomy tube

Place a thoracostomy tube through an intercostal space one to two spaces caudal to the incision prior to closing the thorax.

Rib approximator

Use a rib approximator or have an assistant cross two sutures to appose the ribs.

Median Sternotomy

A surgical procedure that provides exposure to both sides of the thoracic cavity.

Bilateral partial lobectomy

A surgical procedure that can be easily performed through median sternotomy, while complete lobectomy may be challenging.

Structures isolated in median sternotomy

Includes the Caudal Vena Cava, Main Pulmonary Artery, and both sides of the Pericardial Sac.

Indications for a Median Sternotomy

Conditions such as Mediastinal Tumors, Pericardiectomy, Spontaneous Pneumothorax, Trauma, and Exploratory Thoracotomy.

Postoperative considerations

Two or three sternebrae should be left intact cranially or caudally to reduce postoperative pain and prevent delayed healing.

Sternotomy extension for lung or heart exposure

Should extend from the xiphoid cartilage cranially to the second or third sternebra.

Sternotomy extension for cranial mediastinum exposure

Should extend from the manubrium caudally to the sixth or seventh sternebra.

Sternal Saw

Special equipment used for performing median sternotomy.

Oscillating Orthopedic Saw

Another special equipment used for median sternotomy.

Median Sternotomy Procedure

Involves incising the skin on the midline over the sternum and exposing the sternum through sharp incision and blunt dissection.

Sternal saw guide

A feature that sits under the sternum to facilitate cutting without damaging the heart or lungs.

Closure of sternotomy in dogs over 15 kg

Should be done with wires.

Closure of sternotomy in cats and small dogs

Should be done with heavy suture.

Figure-eight pattern closure

Wire or suture is placed around the sternebrae in a figure-eight pattern for closure.

Stability of wire closures

In large dogs, sternotomies closed with wire may be more stable due to healing associated with chondral or osteochondral bridging.

Suture closure comparison

Recent studies indicate that suture closures (polydioxanone or nylon) are mechanically comparable to wire.

Biomechanical loading in closure

Single or double-twist figure-eight patterns centered between two sternebrae are associated with least displacement during loading.

Double-loop cerclage wiring

Should be avoided due to a high failure rate under load.

Median Sternotomy Closure

Suture the subcutaneous tissue in a simple continuous pattern with absorbable suture. Remove residual air from the thoracic cavity and close the skin routinely.

Partial Pulmonary Lobectomy

Performed via Intercostal Thoracotomy or a Median Sternotomy. Identify lung tissue to be removed and place crushing forceps proximal to the lesion.

Continuous Overlapping Suture Pattern

Place a continuous, overlapping suture pattern proximal to the forceps during a Partial Pulmonary Lobectomy.

Lung Excise Procedure

Excise the lung between the suture lines and clamps, then oversew the lung in a simple continuous pattern with absorbable suture.

Thoracoabdominal (TA) Stapler

Used in Partial Pulmonary Lobectomy.

Complete Pulmonary Lobectomy

Ligate and transect the vasculature to the affected lobe.

Satinsky Clamp

Used to double clamp the main bronchus during a Complete Pulmonary Lobectomy.

Bronchus Suture Pattern

Suture the bronchus in a continuous horizontal mattress pattern.

Postoperative Care and Assessment

Monitor respiration closely once the animal begins ventilating on its own.

Thoracic Radiographs

Should be examined for evidence of pneumothorax if there is any doubt about residual air after thoracic closure.

Blood Gas Analysis

Helps evaluate adequacy of ventilation in postoperative care.

Hypoxic Animals Treatment

Should receive oxygen by nasal insufflation or oxygen cage.

Multimodal Analgesia

Needed in all patients undergoing thoracotomy procedures.

Post-op Hypoventilation

Thoracic radiographs indicated to rule out pneumothorax, hemothorax, or pulmonary edema.

Hypothermia After Surgery

Common after thoracic surgery; patients should be rewarmed with warm water bottles, circulating warm water blankets, or warm air blankets.

Postoperative Complications

Reported in 39% of thoracic surgery cases, most consist of wound complications and problems with thoracic drain.

Incidence of Pyothorax

Found to be 6.5% in a study of 232 dogs with a mortality rate of 67%.

Subcutaneous Fluid Accumulation

Can occur at the ventral aspect of the thoracotomy incision; avoided by carefully closing the distal musculature.

Air Leakage or Hemorrhage

Major complication of partial or complete lobectomy; minor air leaks usually seal, but massive air leaks or severe hemorrhage require reoperation.

Median Sternotomy Complications

Adequate closure and leaving several sternebrae intact prevents delayed healing or nonunion of the sternebrae.

Postop Lameness

Associated with pain and severing of the latissimus dorsi muscle; usually resolves within 1 to 2 days.

Monitoring Postoperative Animals

Closely monitor for pneumothorax, hemothorax, or both in the early postoperative period.