Thoracic Surgery Flashcards
List the criteria to define chylothorax on pleural fluid analysis
Pleural fluid with 2/3 positive for
WBC > 1000x106/L
Lymphocytes >80%
Triglycerides >1.1 mmol/L
Cholesterol 65-220 mg/dL
List 3 strategies to avoid duct injury when doing arch dissection?
Keep dissection on the aorta (because the duct lies in between the aorta and esophagus). Higher chance of injuring the thoracic duct if your dissection plane is off the aorta
A large lymphatic crossing the LSCA near its origin could be ligated
Closure of the mediastinal pleura
How do you manage a chylothorax
Dietary exclusion of long chain triglycerols avoids their conversion to monoglycerdies and FFA that are transported as chylomicrons in the thoracic duct. Medium chain triglycerols are absorbed directly into intestinal cells and transported directly to the liver via the portal vein (bypassing the thoracic duct)
Lipistart: 2% protein, 47% carbohydrate, 41% fat (80% medium chain and 18% long chain triglycerols)
Consider U/S IJ/SCV and treat any systemic thrombosis, aggressive diuresis, ECHO and treat CHF, replace CT losses
If CT losses <10cc/kg/day then NPO+TPN x 7 days
Oral vitamin supplementation, poor absorption of fat soluble vitamins may require parenteral supplementation
Check INR, albumin, total protein, Ig and replace as clinically indicated
If CT losses >10cc/kg/day then start octreotide x 14 days at maximum dose
10 mcg/kg/dose IV Q8H and increase by 10 mcg/kg/day to a maximum of 65 mcg/kg/day
Wean octreotide by 25% daily over 4 days
If after completion of NPO+TPN or octreotide the CT drainage is < 10cc/kg/day then trial chylothorax diet and R/A for return to normal diet in 2-4 weeks
Remove CT when < 2cc/kg/day for >48 hours on chylothorax diet
If CT losses >10cc/kg/day then consider thoracic duct ligation, percutaneous thoracic duct embolization, or pleurodesis.
To help identify the site of leakage, cream mixed with a lipophilic green dye may be administered via NG 20 minutes prior to anesthesia. Alternatively, a lymphangiogram/MR lymphangiogram may be performed to aid in localization
Failure of these therapeutic approaches may require pleuroperitoneal or pleurovenous shunt.
Describe thoracic duct anatomy
The thoracic duct originates at T12 as the cisterna chyli.The thoracic duct ascends through the aortic hiatus of the diaphragm entering the posterior mediastinum, still to the right of the vertebral column. It courses posterior to the esophagus at the T7 level and crosses over the midline to the left side of the thorax around the T5 vertebral level. It eventually emptys into the junction of the left SCV and IJ.
List 4 treatments for chylothorax
Medium chain fatty acid diet
NPO/TPN
Octreotide
Steroids
Thoracic duct ligation
Percutaneous thoracic duct embolization
Treat systemic venous thrombosis
Pleurodesis
Pleuroperitoneal shunt
List 3 causes of diaphragm paresis post-op?
Pericardial slit for IMA
Proximal LIMA mobilization where phrenic nerve crosses SCA just lateral to IMA origin
Dissection of SVC for snare
Resection of thymus
Traction injury
Ice
Pericardiectomy
Patient with prolonged respiratory failure post-CAB. Trached x 7 days. Begins to develop bright red blood from trach. What is the most worrisome diagnosis? What investigations might you do, if the patient is stable, to confirm your diagnosis?
Diagnosis:
Tracheo-innominate fistula
Investigations:
Rigid bronchoscopy (can be used to compress anterior trachea & bleeding) with 0o scope with tracheostomy tube removed to examine stoma & anterior wall
Angiography for sentinel bleed or negative bronchoscopy
Patient with prolonged respiratory failure post-CAB. Trached x 7 days. Begins to develop bright red blood from trach. List 4 risk factors.
Risk factors:
Malpositioned trach tube below 4th ring
High lying innominate artery
Long-term ventilation
Excessive movement of tracheostomy
High airway pressures requiring correspondingly high cuff pressures to prevent air leakage
Sepsis
Frequent hypotension
Radiation therapy
Steroid therapy
Malnutrition
Diabetes mellitus
Patient with prolonged respiratory failure post-CAB. Trached x 7 days. Begins to develop bright red blood from trach. What is your initial management?
Basic Goals
Secure airway
Control bleeding
Overinflate tracheostomy cuff, then if necessary slowly withdraw tube with pressure directed against anterior tracheal wall
If overinflation of the cuff does not control the hemorrhage:
An oral endotracheal tube should be placed
The tracheostomy tube is removed
Digital compression of the innominate artery is applied entering the pretracheal fascial plane through the tracheostomy wound
Bluntly dissect innominate artery off the trachea with index finger compressed against the sternum
Successful in about 90% of the cases
Patient with prolonged respiratory failure post-CAB. Trached x 7 days. Begins to develop bright red blood from trach. Describe your options for surgical repair.
Two basic strategies:
Approaches that maintain flow through the innominate artery
Direct repair of the defect OR
Interposition grafting
High risk of failure given local infection
Approaches that interrupt flow through the innominate artery
Ligate artery +/- bypass
Operative mortality: 25%-95%
Describe the WHO classification of Pulmonary hypertension
