Flashcards in CS: Respiratory distress Deck (26):
What system dysfunction does cyanosis suggest?
Respiratory system problem (not cardiovascular)
What should you do with every respiratory case?
Map it out - i.e. localise it to either: URT, LRT, lung parenchyma, pleural space or diaphragm
List methods of oxygen supplementation - 8
- Flow-by tube of oxygen
- Nasal catheter
- Intubation and positive pressure ventilation
- Future - IV oxygen and microparticles
Outline flow-by oxygen supplementation
tube of oxygen held by patient head, cheap, easy, short term, animal needs restraining
Outline mask and hood oxygen supplementation
– improves effectiveness, masks well tolerated usually, not hoods. Can reach 40% oxygen delivery. Problem with a dog that is panting – poorly tolerated. A hood is a cone (post-surgery) which is covered and an oxygen tube is placed under this to deliver oxygen. Probably better than flow-by in terms of efficacy but hard to quantify. Dog will get hot and won’t be able to see.
Outline nasal catheter oxygen supplementation
2 openings in nostrils, deliver a constant stream of oxygen, red rubber catheter higher percentage of oxygen delivered, ideal for restless or panting patients, LA (won’t fit in cage), long term, less waste, may be uncomfortable (the cold oxygen causes jet lesions with haemorrhage). Measure to medial canthus of eye and place this amount down the nose. Bupivicaine local anaesthetic to reduce irritation. Point in a ventro-medial direction. Suture in place (tape round first then suture it) OR use super glue.
Outline cages for oxygen supplementation
box with constant oxygen supply, less stressful, accurate O2 delivery, can be humidified, no restraint, high oxygen flow BUT expensive and wasteful when door is opened. Small animals.
Outline intubation and positive pressure ventilation for oxygen supplementation
may be required to stabilise the animal but may need to sedate or anaesthetise and specialist training/equipment.
What are problems with oxygen supplementation?
avoid over 24 hours (oxygen toxicity free radicals), damage to cell membranes, alveolar collapse, retinal detachment, seizures.
Equipment for thoracocentesis
butterfly needle, 3 way tap, syringe, local anaesthetic
How do you prepare to do a thoracocentesis?
manual restraint, sedation (don’t with dyspnoea), sternal recumbency, aspectic preparation of the skin, LA in SC tissue, muscles at proposed sites of needle injection
How do you perform thoracocentesis?
attach butterfly needle to 3 way tap and syringe, ensure tap is turned off, 7th of 9th ICS half way up thoracic wall or in dorsal third of wall if only air presence is suspected, insert at cranial border of rib to avoid intercostal vessels and nerves. Advance needle lowly in a slightly ventral direction. Turn tap so gentle suction can drain space. Drainage is complete when no further air can be pulled into syringe. Turn tap off. Withdraw needle. Drainage of both sides recommended. Radiography should be performed afterwards (not really necessary if dyspnoea corrects and no other pathology is suspected).
List 3 possible complications of thoracocentesis
lung laceration, pneumothorax (maintain closed system), pyothorax (maintain sterility)
surgical opening of the chest cavity (e.g. for drainage).
When are drains indicated rather than thoracocentesis?
used for neoplasia and serious levels of effusion, allows continuous drainage unlike thoracocentesis (transient, e.g. sampling).
Method - thoracic drain placement
Closed technique, lateral recumbency, affected side uppermost, GA necessary, clipped and prepped. Typically skin incision at 10th ICS to allow SC tunnel to be placed for 2 ICS length so drain enters 8th ICS. Local anaesthetic recommended for patients under GA (bupivicaine). Lift trocar and stap into chest wall. Chinese finger trap suture to secure in place. Monofilament nylon or propylene. AIM = to have the tube lying along sternum and stop at 1st rib. Always radiograph - check placement and that all fenestrations are in chest cavity. Cover incision with non-adherent dressing.
How/when do you remove a chest drain?
- Pneumothorax - removed 24 hours after no air is aspirated. Excess fluid - remove once the daily fluid volume has declined to around 2ml/kg/day (thought to be the amount of fluid produced from the tube irritation itself). Perform without GA, cut sutures, gently pull, close skin incision. Take chest radiography before and 12-24 hours after to check for excessive fluid/air.
Can you send an animal home with a chest drain?
NO - risk of pneumothorax if patient removes the chest drain.
Why is traumatic pneumothorax often bilateral?
due to the fenestrated mediastinum in dogs/cats
2 causes of pneumonthorax
TRAUMATIC - open or closed
Define open traumatic penumothorax
pneumothorax due to direct communication between atmosphere and pleural space.
Define closed traumatic pneumothorax
pneumothorax due to damaged pulmonary parenchyma within enclosed chest cavity.
Outline spontaneous pneumothorax
– always closed, usually caused by blebs or bullae which come from air filled lesions in pleura/lung parenchyma and rupture causing pneumothorax. Especially deep chested dogs. Bleb = air from parenchyma trapped between layers of visceral pleura. Bullae = air filled space between pleura and lung surface following destruction of alveolar wall.
Radiographic signs of pneumothorax
elevation of heart from sternum in lateral view due to collapsed lung lobes, radiolucent area of free air where no pulmonary vasculature, flattened diaphragm maybe.
- TRAUMATIC radiograph– any fractures/ haemorrhage, pleural effusion, pulmonary contusions.
- SPONTANEOUS radiograph – blebs/bullae appear as circular lucent cavities with thin walls at margins of lung lobes.
Prognosis - pneumthorax
TRAUMATIC - good depending on other complications.
SPONTANEOUS – depends on underlying cause severity of damage.