is it acceptable to use mask or chamber to induce patient with respiratory disease?
no, intubate without delay
what is most common cause of megaesophagus?
persistent right aortic arch leading to acquired megaesophagus
What is pathophysiology of pneumothorax?
air accumulates in pleural cavity leading to lost negative pleural pressure --> lungs undergo elastic recoil and collapse
How does pneumothorax appear on rads?
heart has loss of sternal contact dt mediastinal disruption
What type of pneumothorax does wound in thoracic wall produce?
What is spontaneous pneumothorax?
- pulmonary blebs and bullae in parenchyma that rupture
- "lung leak"
In the event of a mild closed pneumothorax that is not progressive and there is no severe hyperventilation or respiratory acidosis, what should be done?
treat with cage rest and observation
In event of moderate closed pneumothorax in which there is resp. distress, what should be done?
treat by thoracocentesis initially; if recurs, place thoracostomy tube
In severe closed pneumothorax (progressive, marked resp. distress), what should be done?
- thoracostomy tube with continuous suction or Heimlich valve
- -if leakage is significant/persists >5-7d, do exploratory thoracotomy
what should be done for tension pneumothorax (high pressure closed system)?
trocar to make open pneumothorax then tx
What are rad signs of pneumomediastinum?
air highlights structures you don't normally see; like aorta
How is SQ emphysema treated?
- bandage to send SQ air towards abdomen and it will absorb in time
- will NOT help to try to aspirate air
When does patient present with paradoxical respiration?
when more than 2 fractures in consecutive ribs, chest rising on expiration
What are options for repairing tramatized thoracic wall?
- polypropylene or PDS mesh
- or omentum
how do you test the lung for punctures/leaks?
flood cavity with saline --> give breath and see if air bubbles present
what is diagnostic evaluation is suspect chylothorax?
- thoracocentesis -> test fluid's triglyceride levels
- TG in chyle is higher than serum sample
What is medical treatment for chylothorax? What is sx options?
- drug called Rutin
- sx: ligate thoracic duct or subtotal pericardectomy
With PDA, which direction shunt can be operated on?
- left to right shunt (aorta to pulmonary artery)
- (1-2% have shunt in other direction; repair would lead to fatal increase in lung pressure)
Are males or females more likely to have PDA? what type of murmur is produced by the defect?
- females (4:1)
- continuous machinery murmur at left heart base; sometimes palpable fremitus
What is significance of lacerating phrenic nerve?
paralysis of diaphragm but patient can survive because they rely more on intercostal muscles anyway
Before surgery on PDA, what are some treatment considerations?
treat heart failure/edema with diuretics and digitalis as needed
What are options for surgically occluding the patent ductus? which has higher success rate?
- ligature (less expense and higher success)
- --Jackson and Henderson modification safer than other ligature techniques
- coil occlusion and Amplatz occlusion
Where is sx approach on dog v. cat for PDA?
- left intercostal
- 4th = dog
- 5th = cat
When placing ligatures to occlude PDA, use mono or multifilament? Is aorta or pulmonary side tied first?
- multi/braided so doesn't slip
- aorta tied 1st
Is pericardium closed with suture? Is thoracostomy tube placed before closing?
- do not need to suture pericardium
- place a tube
What is the Branham reflex? How is this treated?
- reflex bradycardia once ligatures placed on PDA
- tx: atropine (bradycardia less severe if ligature tightened slowly)
When do signs of persistent right aortic arch show up?
- at weaning--> regurgitation due to constricted esophagus
- can have ventral displaced trachea on rads +/-signs of aspiration pneumonia
With persistent right aortic arch, what structure entraps the esophagus and needs to be transected?
ligamentum arteriosum (some also have PDA so careful before ligate bc the "ligament" could be a patent vessel)
Once ligamentum arteriosum is dissected away, what should be done to esophagus?
bouginage or other technique to dilate the stricture caudal to the heart (will need to eat upright for life)
After PDA or PRAA surgery, should post-op antibiotics be administered routinely?
no, this is a clean, elective surgery
What is prognosis for pt with PRAA?
- better if caught early and o'willing to manage upright feedings
- megaesophagus rarely completely reverses
As an incidental finding, if you discover a persistent left cranial vena cava during sx, should this vessel be ligated as well? what if you find a hemiazygous vein?
- not vena cava (needed for drainage of head)
- can ligate hemiazygous
What structures lie on the dorsal and ventral aspect of the esophagus near cardia and should be carefully dissected out of the way before manipulating esophagus?
branches of vagus nerve
Describe the turkel catheter used for thoracocentesis.
- red mark visible when catheter meets resistance --> not in far enough
- green = good placement
What size tube is used for thoracostomy? What should you know before making additional holes in the tube?
- should be similar diameter as main stem bronchus
- or 1/2-1/3 intercostal space
- no more than 3 add't holes, no more than 1/4 diameter of tube to avoid kink/break off
What is the new technique for placing thoracostomy tubes that is safer and allows tighter fit than tunneling SQ?
assistant pulls skin cranially --> make stab incision where tube will go --> insert tube --> let go of skin
Is heimlich valve used in patients greater or less than 15kg?
- greater than 15kg
- (3way stop cock for smaller)
what are 2 methods to reduce post-op edema when reexpanding lungs in surgery?
- insufflate lungs gradually (semi-collapsed lobes can be left behind)
- leave thoracostomy tube in place for 12hrs to aspirate fluid as needed
A low pressure suction system can be attached to thoracostomy tube post op (20-30cm below pt). What are the 4 containers involved in the system before the connection to suction?
- fluid trap --> air trap --> regulator bottle --> moisture trap --> all connected to suction
- (3 container apparatus has collection --> water sealed bottle-->suction control bottle-->to wall suction)
when do you know its safe to remove a tube in a 20kg patient?
- when collection fluid is <50 cubic cm in 24 period
- rads at 24hr do not show any free fluid/air
- drainage consistent with volume the tube itself is producing (2ml/kg/day)
Where is sx approach for subtotal pericardectomy?
- median sternotomy (preferred)
- lateral thoracotomy at 4th/5th space if less pericardium to remove
For subtotal pericardectomy, where is incision in relation to phrenic nerves?
circumferential ventral to the nerves
What is prognosis for granulomatous pericarditis? idiopathic pericarditis?
- fair for granulomatous
- good for idiopathic (70-80% return to normal)
what is prognosis for patient undergoing subtotal pericardectomy as treatment for chylothorax?
what is purpose of pleuroperitoneal shunt?
o' pumps to drain peritoneal cavity when pt has difficulty breathing; salvage shunt when fluids continue to accumulate in thorax --> shunt to abdominal cavity