Resp Flashcards
Minimum staffing needs to do a perc Trachy
3
Two medics
One assistant
Cuff pressure in a perc trachy
20-30
Berlin criteria for ARDS
Timing - within one week of clinical insult
Chest imaging - bilateral opacities, NOT explained by effusions or collapse, and in keeping with pulmonary oedema
Origins of oedema - respiratory failure not explained by cardiac failure or fluid overload. Consider an echo
Hypoxia - PF ratio
26.6 to 39.9 mild
13.3 to 26.6 moderate
Less than 13.3 severe
Berlin criteria timing
Within one week of the clinical insult
Berlin criteria chest imaging
Bilateral opacities, not explained by effusions or collapse, and in keeping with pulmonary oedema
Berlin criteria hypoxia
PF ratio
Mild 26.6 to 39.9
Moderate 13.3 to 26.6
Severe less than 13.3
Moderate asthma
PEFR 50-75% predicted
Severe asthma
PEFR 33-50 Resp rate more than 25 Heart rate more than 110 Low or normal pCO2 Cannot complete a sentence
Life threatening asthma
PEFR less than 33% Silent chest Feeble effort Hypotension Arrhythmia Bradycardia Hypoxia less than 92% or pao2 less than 8 Hypercapnia Altered neurological state
Risk factors for fatal asthma
Previous life threatening with acidosis or need for ventilation
Hospital admission in last year
Three or more asthma meds for chronic control
Heavy beta agonist use
Brittle asthma :
Type 1 wide PEFR variability
Type 2 sudden severe attacks despite being well controlled
Adverse psycho social circumstances - non compliance, alcohol abuse, social isolation
CURB 65 score
Confusion Urea more than 7 Resp rate > 30 Systolic < 90 Age> 65
Effusions based on protein
Transudate < 30g/L
Exudate > 30g/L
Lights criteria
An exudate is suggested by
Pleural to serum protein level > 0.5
Pleural to serum LDH level > 0.6
Pleural LDH level that is more than 2/3 upper limit of normal serum LDH level
Pleural fluid features of an empyema
PH less than 7.2
Glucose < 3.3
Bacteria on microscopy
Fluid LDH > 1000
What is compliance
Change in lung volume per unit change in pressure
What is the compliance of the lung and the chest wall
They are the same
200ml/cmH2O
What is the total compliance and how is it calculated
100ml/cmH2O
Calculated at the sum of reciprocals
1/total = 1/chest wall + 1/lung
= 1/200 + 1/200
= 2/200
= 1/ 100
Therefore 100
What is static compliance and how is it measured
Compliance in the absence of gas flow
Do an end inspiratory hold manoeuvre or add insp pause to estimate PLATAEU
Pressure
Eqn:
C= Vt/(Pplat - PEEP)
What decreases static compliance
Lung parenchyma disease ARDS, pneumonia, fibrosis
Chest wall disease: kyphoscoliosis, obesity, burns
Raised IAP
What is dynamic compliance
What is the eqn
Measured during rhythmic breathing
Determined by the PEAK pressure, not the plateau
Cdyn= Vt/Ppeak - PEEP
Which compliance is smaller and why
Dynamic compliance is smaller
Peak (the measurement of dynamic) is higher than plateau (the static measurement)
Peak pressure represents compliance of lung, chest wall and pressure needed to overcome airway resistance
Usually dynamic is 2-3 ml/cmH2O less than static
The difference between dynamic and static is quite small, what would make it increase
Obstructive airway disease, where higher pressures are needed to overcome the overcome the increased resistance
What is the relationship between alveolar minute ventilation a PaCO2
Doubling the MV halves the paCO2
What is the relationship between minute volume and pao2
Increasing the minute volume does little to o2, incredibly small rises, but parallel lines occur on increasing the Fio2. The o2 starts to fall when the MV drops below 5
