Small Ani. Sx- Thoracic Sx 2

drraythe's version from 2016-04-29 14:14


Question Answer
is there a gender discrepancy in the animals who suffer from PDA?Females:males 4:1 (MORE FEMALES) (esp in GSD)
which side do you laterally approach from if you want to tx PDA?Left
the left is better for seeing the heart and lungs- what is the right side better for seeing?see eso better, azygous vein, and see trachea a bit better.
what will a PDA sound like upon ascultation? where do you hear it?continuous "machinery murmur" at LEFT HEART BASE
Before you sx tx the PDA, what other possible comorbidities might you have to tx first?Treat pulmonary edema, atrial fibrillation or congestive heart failure with diuretics and digitalis as necessary before surgery
what are 3 diff options for how to occlude the PDA?(1) surgical ligation (2) Coli occlusion (3) Amplatz occluder
how does the "coli occlusion" tx work for PDA?coil placed in retrograde manner from aorta to patent ductus, strands maintain coil in place. Works as scaffold for clot formation and occlusion of ductus.
how does the Amplatz occluder work to tx PDA?This is a basket-like occluder that also works as scaffolding for clot formation and eventual occlusion of the PDA. Is threaded from femoral artery all the way to the PDA so fluroscopy often used.

WHERE do you perform the thoracotomy for a PDA? Side of body? IC space? Sp variation?DOG: Left side 4th IC space. CAT: left side 5th IC space
which is better- surgical ligation or coil occlusion for tx of PDA?Sx ligation is Less expensive and higher success rate than coil occlusion (In hands of experienced surgeon, success rate > 95%)
what is the suture of choice for PDA ligation and why?SILK, bc braided for good knot security, and also will not migrate or get displaced. need to use large size suture material! Because if small size suture, need to tie tight, might cut through ductus and bleed to death asap.
how do you know where to dissect for going in to do a PDA ligation?go to base of heart and where you feel fremitus, that's where you dissect. there will be CT there, around the PDA. If you have angled hemostats (or curved halstead) dissect cr and ca of the PDA and be careful with wide and short ones which are extra easy to damage.
how should you dissect the PDA from the surrounding CT and why must you be so careful?Use angled hemostat/curved halstead. Give yourself a little space when you're dissecting. If you're too close you might be peeling off layers of the wall of the PDA, and you can accidentally make it too thin and it will break and start to hge. so stay away a few ml from the ductus and dissect bluntly. then take it out to lose it so you can see what youre doing.
once the CT is dissected around the PDA, how do you go about ligating it?...with vagus nn in vicinity, bluntly dissect and lift it up or down for it to be out of your way. Use stay suture. pass forceps/halsteads around under ductus, grab suture material. Pull through and ligate.
details on how to ligate the PDA- which side of the PDA do you ligate first? When you first ligate the PDA, what happens? Do you dissect?Ligate AORTIC side first-- when you initially ligate, there will be bradycardia (branham sign). THEN suture pulmonary side. It is not necessary to transect the PDA once ligated. However, still a risk of it recanalizing, in which case the procedure must be repeated.
If you are closing the chest well, should you suture plura back together?don't have to
do you ligate pulmonary or aortic side of PDA first?AORTIC side first
what is the branham sign? prevention/what should you have in case this becomes a prob?when you first ligate the PDA, the heartrate will dec (bradycardia). If tighten slowly, might be less of a problem. Atropine should be available in case bradycardia too low
what is the Jackson & Henderson modification/ how does it work?If you are worried about bluntly dissecting around the PDA, esp if it is a short and wide one, you can use this technique to avoid this step. Just dissect ca to PDA and around the BACK of the AORTA instead. Pass the suture (extra long and folded double) around the back of the aorta. Then dissect just Cr to the PDA. Then, from cr side of the PDA, grab the suture that's looped around the back of the aorta and pull it through. then gently perform a sawing motion to displace suture through CT from top/back of aorta to behind the PDA. Cut looped end so now have 2 sutures for aortic and pulmonary side are now set up to ligate as you would normally. (the braided suture can saw through CT but not the PDA)
If you see the aorta bulging, what might this tell you about the PDA?probably more longstanding/chronic

PRAA (persistant Right aortic arch)

Question Answer
Do you want to ligate or cut a PRAA?ligate instead of cutting bc sometimes might have both a PDA with a PRAA...minimal chance but to prevent any accident, ligate before cutting.
WHEN do you usually see CS of PRAA? what are main CS/vs what concurent CS might you see?Show clinical signs at weaning- usually regurg. However, might see concurrent resp signs (aspiration)
how might a PRAA appear radiographically?may have ventral tracheal displacement on survey radiographs.
you open the chest and see the aorta, pulmonary a, and the dilated esophagus. Now explain the procedurecareful to dissect PRAA from CT in its entirely. place ligatures, can ligate either one first (but maybe aortic first just to keep in habit). You want to ligate just in case there is a persistence of the ductus. After ligating, transect the PRAA. Then dissect bluntly around the eso, bc there has been a stricture and aorta against eso has caused thickened area on surface, so debride area where stricture is to help make lumen normal again. Maybe consider passing tubes to help expand eso lumen (like boughienage)
after sx tx of a PRAA, how will you feed the animal?start with feeding a gruel....take a day or two to inc thickness/hardness of food. You might have to keep feeding them in a standing position to have gravity assist food going down eso and not pooling in stretched out portion
two things you need to do for post-op management of PRAA after sx tx?(1) Treat pneumonia if necessary (2) Elevated feeding of moist solid food - may need to continue for life
prognosis of PRAA--> what bout that megaeso?Use long-term follow-up esophagrams to assess recovery. The Megaesophagus rarely completely reversed, but With early surgery reversal more likely. If esophagus diameter > twice normal, reversal very unlikely
when would reversal of megaeso be very unlikely?if greater than twice the normal size
what are two variations in vasculature you can see when performing a PRAA correction procedure?(1) 40 % of cases persistent left cranial vena cava (2) also there can be hemiazygos vein (can be sacrificed if it's in ur way during sx)
What is this little bump and what might it help you with? This little LN might help you bc it is often RIGHT before the stricture
aside from a lateral thoracotomy, how else might you approach the PRAA repair sx?esophageal approach (dont forget sew back wall first then front wall of eso)
If you have had too much expansion of the ribs for your surgery, and now they are not opposing well to allow you to place your sutures-- what are some things you can do to dec it and keep it decreased?There are jacks which jack ribs inward instead of outward! can use these, and then suture using ribs as braces
If you are sewing through thoracic wall and you must pass with your needle into the thoracic cavity, how can you dec chances of stabbing or grabbing lung parynchyma when taking a bite?pass the SWAGED end FIRST

thoracocentesis/Subtotal Pericardectomy

Question Answer
4 tools which you can use to perform a thoracocentesis?(1) IV catheter (cut holes in it) (2) Turkel catheter (3) 16-18G needle (4) thoracostomy tube
what is this weird thing and why does he like it so much? This is a Turkey cath. The stylet (bottom thing) has a blunt end to go into cath look alike (top thing). and that cath has a 3 way stopcock pre-attached to it so you can immediately begin to use it. When you place the stylet in, and you use it to pierce the thoracic wall, there is a prong on stylet. When It is being pressed on/in contact with something firm (like when you press on it with finger like on pic) there is a red band. So when enter thorax past the wall, Then there is no pressure, and instead of red will show green band, so you know you can slide cath in without causing damage. When you pull out the stylet, there is a seal so only communication via T-port.
as a rough guideline, the tube diameter must be similar to the..diameter of the main bronchus, OR 1/2 - 1/3 the width of the intercostal space
what do you want the consistency of the T-tube to be like?flexible, but not collapsible
Do you want holes in the T-tube? how many? Size?number of holes= no more than 3 (each additional orifice only increments the flow by 5% ) (help prevent occlusion). Size of holes= 1/4 the diameter of the tube (diameter > 1/3 cause weakness and predispose for kinking)
dogs & cats 3-6 kg should probably have a tube size 14-16 Fr.
dogs 7-15 kg should probably have a tube size 18-20 Fr.
dogs 16-30 kg should probably have a tube size 22-28 Fr.
dogs > 30 kg should probably have a tube size 30-36 Fr
Explain a way you can get a really good seal when placing a thoracostomy tubegrab skin and pull taught in cr direction, make stab incision at level of IC space that space you want tube to go in. Then bluntly dissect. Push cath through incision. Then when release skin that was pulled forward to go back into normal position, will slide down and the incision will no longer be over the incision that is in the IC space, and the skin will adhere like a tight glove
When you are pushing the tube into the thorax you need to hold the tip of the tube with an instrument-- what is the proper way to hold it?grab from below, not from above. If from above, rubber is in the way and it rebounds off the wall and you cant pierce it. You want to grab from under with tips slightly forward so you can pierce wall.
if you have a patient that weighs less than 15 kg, what can you use as means of suction?syringe with a 3-way stopcock
if you have a patient that weighs more than 15 kg, what can you use as a means of suction?Heimlich valve
PRE (pulmonary re-expansion edema) happens because of what? how can you help prevent this?dont overinflate lungs, when giving the "sigh"-- dont go over 20cmH2o or will cause PRE(pulmonary reexpansion edema). Overdoing reexpansion/squeezing bag too hard--> hurt parynchyma-->edema--> make resp worse. Can try to help avoid by (1) insufflate lungs gradually (2) semi-collapsed lobes can be left behind
what is this? what should you DEF not forget if you are going to use this? This is a water trap. Complicated, so don't let anyone touch unless they know what to do. **need to be more than 20-30 cm. below the patient
If you want a FAST nerve block, which LA? if you want a LONG LASTING nerve block, which LA?intercostal nn block w/ lidocaine- dorsal and ventral- instant. bupivicaine will last longer.
at what point will you want to remove the T-tube? (3)(1) drainage reduced to a volume that is consistent with the one produced by the tube itself: 2 ml/kg/day. (2) X-ray at 24 hs. does not show air or free fluid (3) when collection of fluid is 50 cm3 or less in 24 hs (these numbers are for a 20kg dog)
**how much fluid is produced in the thorax as a reaction to the tube being in there?2ml/kg/day
what is the approach for a Subtotal Pericardectomy?Median sternotomy preferred!! If choose Lateral thoracotomy at 4th or 5th intercostal space - less of pericardium removed
how do you make incision for a subtotal pericardectomy?Circumferential incision ventral to phrenic nerves
what might a subtotal pericardectomy tx?chylothorax
prognosis of Granulomatous pericarditis after subtotal pericardectomy?fair
prognosis of Idiopathic pericarditis after subtotal pericardectomy?GOOD! 70-80% return to normal (Remaining cases have recurrence of effusion, may require pleuroperitoneal shunt)
If there is a CHRONIC chylothorax, what is really the only way to try to fix it?pleuroperitoneal shunt. Puts elastic tube through diaphragm, and using valves which are placed SQ so owner can push several times a day and drain from thorax into abdomen. Basically lets you buy some good quality of life for the pt. multifenestrated shunt.