Respiratory Flashcards
ARDS Definition
Berlin Criteria
- Acute Onset < 1 week
- PF ratio < 300 (40)
- Bilateral opacities on imaging not attributable to LVF
- Patient ventilated with a PEEP >/= 5
Lung Protective ventilation
ARDSnet trial
- TV 6-8mls/kg of IBW
- Pplat < 30
- PEEP titrated to FiO2
- Permissive hypercapnia
ARDS Management Strategies
Proning at least 16 hrs/day - PROSEVA (2013)
NMB - ACURASYS (2010)
ECMO - CESAR (2009) showed reduced mortality
- EOLIA (2018) showed no change in mortality but a high crossover rate
Emerg Trache Mx
O2 to mouth - waters circuit to trache
Check capnography - is patient breathing?
HELP
Attempt ventilation via trache
Remove inner tube - try to pass suction catheter - Can I?
Deflate cuff - ?breathing
Remove trache and reassess the stoma and mouth - ?breathing
Cover stoma
Bag/mask ventilate orally?
Insert supraglottic airway and gently ventilate
Plan for oral ETT intubation - likely to be difficult - pass beyond stoma
Can attempt stoma intubation with small ETT if above difficult
CAP
CURB65 - Confusion, Urea > 7, RR > 30, BP <90 or <60, Age > 65
Comm - Strep, Haemophilus, Atypicals (mycoplasma, legionella) - Amox, clarithromycin
Hosp - Gram -ve, MRSA - Taz
ABCDE, surviving sepsis, Abx
Capnography
Phase 1 - insp baseline
Phase 2 - exp upstroke
Phase 3 - alveolar gas plateau - ETCO2 = highest point on plateau
Phase 0 - Insp downstroke
Asthma - flattening of upstroke and loss of plateau
Loss of trace = decreased CO/cardiac arrest, large V/Q mismatch, pulm oedema, equipment issue, loss of ETT
CO2 vol trace - gives vent/perfusion info, dead space measurement, CO2 elimination
Spontaneous Breathing Trial
Traditionally attach patient to t-piece and allow top breathing unassisted
Generally now use ‘minimal’ ventilator settings (PEEP 5 and PS 7-8) for 30 - 120 mins.
Failure: Objective - 1 - RR > 35 2 - Sats < 90% 3 - HR >140 or change 20% 4 - BP > 180 or <90 Subjective - 1 - Agitation 2 - Anxiety or increased WOB
Readiness to wean
Predicting successful weaning 1 - RR < 35 2 - TV > 5mls/kg 3 - RSBI < 100 (likely success if < 65) 4 - Max insp pressure < 20cmH2O
Haemodynamically stable, FiO2 < 50%
Co-operative, good cough, no excessive secretions
Failure to wean
Resp 1 - inappropriate ventilator settings 2 - thick/copious secretions 3 - Effusions, pulm oedema, diaphragm splinting 4 - Met acidosis, shock
CVS
1 - IHD, valvular HD, CCF
Neuro/Musc
1 - Decreased central drive - sedation, brain stem pathology
2 - Neuromuscular pathology - GBS, CIPN, electrolyte disturbance
3 - Neuropsychological - anxiety, delirium
Nutrition
Anaemia, malnutrition, obesity
Pleural effusion
Approach:
Any resp compromise? - if so drain
Unilateral or suspicious? - if so tap
Tap shows empyema - then drain (pH < 7.2) - normal pH = 7.62
Lights criteria
Pleural to serum prot > 0.5
Pleural to serum LDH > 0.6
Pleural LDH >2/3 upper normal limit
Proning
Improved V/Q matching by ventilating previously dependent areas
Redistribution of oedema
Mediastinal weight moved to sternum rather than lung
Increased FRC
Reduced atelectasis
Improved diaphragm function
ECMO
Complications
- bleeding
- haemolysis
- equipment failure
- clot formation
- air embolism
Pneumonia
Strep p
Haemophilus
Moraxella
CURB65 0-1 (home), 2 moderate, 3+ severe
urea > 7, RR > or = 30, SBP < 90 or DBP <60
Abx: amox and clarithromycin
Atypicals: Mycoplasma and chlamydia - don’t have accessible cell walls for penicillins
Influenza
Flu vaccination:
Age > 65, children 2-10, pregnant, chronic respiratory/CVS/DM/renal, immunosuppressed, obesity, RH/NH, frontline healthcare workers, care home staff
Acts against 3-4 viruses that are most likely to cause an epidemic in up coming season - 60-80% protection - inactivated or live attenuated (nasal in kids)
Flu A - subtypes, cause pandemics, hosted in birds
Flu B - two types, contribute to seasonal epidemics but never caused a pandemic, humans main reservoir
Present:
Fever, malaise, URT, headaches, arthralgia, viral pneumonitis (ARDS)
Complications: Resp: secondary pneumonia, ARDS CVS: myocarditis Neuro; GBS, encephalitis, meningitis Musc: myosotis, rhabdo Renal: AKI
Meds:
Neuroamindase inhibitors- Oseltamivir (oral, SE - N&V, headache, diarrhoea, psych), zanamivir (inhaled, SE - bronchospasm)
M2 inhibitors- amantidine (hallucinations, movement disorders)
Post-exposure prophylactics
Pregnant patient with flu: High-risk for severe flu, spontaneous abortion, pre-term labour Involve obstetricians O2, resp support Early antivirals Antipyretics
APRV
P high - around 30cmH2O
P low - always 0
T high - around 4-6 secs
T low - around 0.5 secs - aim to achieve 50% exp flow time
Advantages
- Lung recruitment
- Less lung trauma
- Spontaneous breathing
- reduced LV intramural pressure
Disadvantages
- can not be used in hypovol patients
- worsen RV failure
Contraindications
Profound CVS instability - recent pulm surg- severe bronchospasm - pulm HTN
