Respiratory Module 4 Flashcards
Two mechanisms of pulmonary edema
- High pressure edema: CHF, volume overload
- Increased permeability edema: any disease process that damages the capsular endothelium or alveolar epithelium - increases vascular permeability within the lungs
Management of cardiogenic pulmonary edema
- Frusemide 2-3mg/kg IV or IM
- pink froth: 4-6mg/kg
-repeat q30mins - 10-30mins to see effects
How does frusemide work to reduce PE
Clears PE by reducing blood volume and reduction in pulmonary capillary pressure
- works directly by affecting pulmonary vascular effects and bronchodilatory effects
What are 4 non-invasive ways of delivering oxygen therapy?
- Oxygen tents
- Oxygen mask - FiO2 35% if loose, 50-60% if tight, tightfitting
- Flow by - 25-40%
- CPAP (continuous positive airway pressure) - need heavy sedation required, poorly tolerated
What are 5 invasive ways of delivery oxygen therapy?
- Intubation
- Transtracheal O2 40-60%
- Nasal prong/High flow O2 25-50%
- Nasal catheters 40-70% - jet lesions
- Naso-pharyngeal catheter - BOAS (deeper in phayrnx
How to preform a thoracocentesis?
- O2 therapy flow by
- Clip both sides of chest and sterile prep
- Mild sedation: Butorphanol/Midaz + ketamine
- Ideally 3 people, to hold, to hold needle and one
for syringe - Location: 8/9th rib intercostal space (ventral 1/3 fluid, dorsal 1/3 air)
- Lidocaine LA - 1mg/kg both sides cats/dogs
What are the chest drain techniques?
- Seldinger
- Over the wire
- Narrow bore drains
- GA or sedation
- Better tolerated
- Less traumatic
- Can be used for pyothorax
- Trochar Drain
- GA only
- Must be tunnelled
- Forceps insertion
- GA only
- Must be tunnelled
How to place a seldinger chest drain?
- Measure from tip of axilla (2nd rib) to 8th/9th
intercostal space - Infiltrate LA
- Measure a releasing incision with number 11
blade - Advance a large catheter (14g) perpendicular in to
the chest - Turn catheter toward ipsilateral elbow and
remove stylet - thumb over the top - Slide in the guide wire to the marked amount
(hold on to the whole time) - Remove catheter over the wire
- Slide on the drain, twisting motions, remove
guide-wire and place thumb over the top - Thumb over the end after removal of the guide
wire or clamp - Sutures through wings of butterfly and then
neck of drain - Orthogonal views of x-rays
What are options for relieving a complete obstruction?
- Needle Tracheostomy
- Clip a patch over ventral neck
- Large bore needle inserted between tracheal
rings - IV catheter
- Cricothyroid ligamnet - easier to palpate, distal to
adams apple
- Attach O2 - Surgical Tracheostomy
- 2-5cm midline incision extending caudally from
cricoid cartilage
- Use retractors to see field, dont dissect lateral to
tracheal as recurrently laryngeal nerve is there
- Identify the midline raphe between the
sternohyoid muscles (white line)
- Blunt dissection through raphe then dissect
muscle bellies to trachea
- Loop sutures through 3-4 or 4-5th ring and label
up/down
- Incise through annular liagment - NEVER more
than 50% circumference
- Place in tracheostomy tube
- Connect to O to and get tape one
- Close skin around incision
- Heat and moisture exchanger
What are causes of non-cardiogenic pulmonary edema?
Broad category of increased permeability edema - inflammatory diseases
- Neurogenic PE: seizures, head trauma,
electrocution - Negative PE: dry drowning,
strangulation, sudden/sharp tug on lead - Aspiration pneumonitis/pneumonia
- Vaculitis
- ARDs
- Pneumonia
- Re-expansion PE
- Drowning Injury
- PTE
- Smoke inhalation
What are predisposing factors to aspiration?
- LP
- Megaoesophagus
- V+
- Regurgitation
- Sedation/GA
- Delayed gastric emptying
- Gastric intubation
- Seizures
What causes aspiration pneumonitis?
This is inflammation of the lung secondary to inhaling a chemical irritant - may or may not progress to pneumonia
- persists up to 48hrs, vascular permeability occurs 1-2 hours after incident
Treatment of aspiration pnuemonitis?
- Oxygen
- Nebulisation
- Light exercise - to promote expectorisation
- Mucolytic - n-acetyl
If progresses to pneumonia
- E.coli most common - 20mg/kg IV q8hrs
- Doxy if puppies
What causes ARDs and how is it diagnosed clinically?
ARDs is a syndrome that is usually a life threatening complication of critical illness - massive inflammatory process leading to alveolar damage characterised by protein rich inflammatory edema within the alveoli followed by fibrotic changes
- pulmonary or extra-pulmonary causes
Diagnostic criteria
1. Acute onset dyspnoea <72hrs
2. Pre-existing severe acute clinical illness
3. Bilateral pulmonary infiltrates
4. Severe hypoxaemia on room air or PaO2
<45mmHg, SPO2 <85%, A-a gradient >50
5. No heart disease
What are causes of PTE?
- Immune mediated disease
- Sepsis
- Trauma
- Neoplasia
- Pancreatitis
- Surgery
- DIC
- Endocarditis
- Myocardial diseases
- FIP
How to choose clot preventative agents?
PTE
- Venous embolis: composed of predominantly
clotting factors
- Anticoags > Antiplatelets
- LMWH, rivaroxaban, anti-Xa agent
ATE
- Arterial embolis: composed of platelets
- Antiplatelet > Anticoags
- clopidogrel
When PTE dissolves can cause a shower of smaller emboli that can cause microscopic PTE
How does smoke inhalation cause injury?
- Direct thermal injury
- Super heated matter carried further down tree
- Irritant gasses (amonia, HLC, benzene)
- Carbon monoxide toxicity
- Cyanide toxicity - from burning plastics/nylon
- Smole inhalation: inactivation of surfactant =
shear injury/atelectasis - alveolar haemorrhage = obstruction from bleeding
Treatment of smoke inhalation?
- Oxygen - 100% O2 therapy via intubation
- Will quickly reverse carboxyhb by out competing
the CO for Hb receptors
- On room air will take 3.5-6hrs but on 100% O2
would take 80-90mins
- Will quickly reverse carboxyhb by out competing
- Mechanical ventilation
- Terbutaline (0.01mg/kg IV, IM) - especially if
wheeze - N-acetylcystein to scavenge for free radicals and even can be mucolytic
- Abs if indicated by BAL
- Judicious fluids
Causes of pulmonary haemorrhage?
- Pulmonary contusions
- Secondary to trauma
- Coagulopathy
- Thrombocytopenia
- Pulmonary inflammation
- Neoplasia
- Thromboembolism
- Lepto/Lungworm
- CHF
Management of pulmonary contusions?
- O2 provision
- Will get worse over 48hours and then should stop
progressing and resolve over 3-10 days - Rads lap about 12-24hrs
- CT better
- No abs needed
What are causes of lung lobe torsion?
- Sighthounds and pugs - idiopathic due to
conformation - Neoplasia
- Pleural space disease
- Trauma
Left cranial lung lobe is the most common in pugs
Right middle and left cranial in sighthounds
Acute or chronic
What are the 4 mechanisms of pleural effusion?
- Increased hydrostatic pressure - CHF, pericardial
disease - Increased vascular leakage - vasculitis (secondary
to sepsis, trauma, IM disease, neoplasia,
pancreatitis) - Decreased lymphatic drainage:
obstruction/neoplasia leading to increased
venous pressure and increased permeability - Decreased oncotic pressure: hypoproteinaemia
(decreased albumin = decreased oncotic pressure
= deceased water in vessels = increase in fluid
accumulation)
Investigating PE after ruling out cardiac disease?
CBC
Comp
Trigly/cholesterol
Clotting
4Dx snap
FELV/FIV
FIP PCR
Common causes of pyothorax
Dogs: secondary to migrating FB or penetrating injury, haematogenous spread
Cats: Penetrating injury to chest from bite wounds, extension of pulmonary infections, haematogenous spread
Dx and Medical Mx of Pyothorax
Dx - intracellular bacteria in plerural fluid, CT
Mx-
1. Bilateral chest drains
- Flush chest regularly - 20ml/kg in small aloquats
(stop if losing more than 10ml into chest),
warmed hartmanns and flush till clear. q4-6hrs
and then decrease q6-12hrs, generally needed for
5-7 days - ABs - coamox + metro pending culture/sens
Remove drain when fluid production 2ml/kg/day per drain
