Investigations - respiratory Flashcards
What conditions are FEV1/FVC ratio impaired in?
Obstructive lung disease
Why is there normal FEV1/FVC ratio in restricitve lung disease?
Equal impairment of each
What is BNP
Brain Natiuretic peptide - hormone secreted by myocardium in response to wall stress eg pressure overload. Normally only small levels.
When do you test BNP
Testing for heart failure when patient presents with SOB, fatigue and pneumonia
What is NIV
Non invasive ventilation eg CPAP
What does CPAP do
VENTURI mask
What does PERC do?
Rules out the possibility of a PE with no criteria prior and a chance of <15%
Criteria for PERC
Age over 50
HR over 100
O2 less than 95% oRA
Unilateral leg swell
Haemoptysis
Recent surgery or trauma
Prior PE or DVT
Hormone use
If anyone of above is positive, cannot rule out PE
What is an sPESI?
simplified PE severtiy index
Groups patients into low or high rusk groups for mortality based on clinical parameters for PE within 30 days
What sPESI score predicts high risk mortality?
1 or more = high risk adverse outcomes next 30 days
What does Wells score test?
Risk of developing DVT
What is WELLS score used for?
Whether to have CTPA to investigate for PE
Criteria for Wells
Active cancer, or cancer that’s been treated within last six months 1
Paralyzed leg 1
Recently bedridden for more than three days or had major surgery within last four weeks 1
Tenderness near a deep vein 1
Swollen leg 1
Swollen calf with diameter that’s more than 3 centimeters larger than the other calf’s 1
Pitting edema in one leg 1
Large veins in your legs that aren’t varicose veins 1
Previously diagnosed with DVT 1
Other diagnosis more likely
Criteria sPESI
Age, years >80
History of cancer
History of chronic cardiopulmonary disease
Heart rate, bpm ≥110
Systolic BP, mmHg <100
O₂ saturation
Gold/yellow top bloods
Kidney function - U+Es
HcG
Troponin
CRP
LFTs
Bone Profile
Thyroid function
when is someone unsuitable for spirometry
- Recent surgery eg opthalmology/abdominal/thoracic
- Recent cardiac arrest
- haemoptysis
- Vomiting
- TB
- AAA - if aneurysm >6cm - relaxed VC if required for surgery
- Pneumothroax
- Caution with cough syncope
- Confusion, dementia
What should be avoided pre spirometry
SABA - 4 hours
LABA - 12 hoours
SA anticholinergics - 6 hours
LA anticholinergics - 24 hours
Performing vigorous exercise 30 mins
Smoking 24 hours
Wear tight fit clothing
Alcohol - 4 hours
Eating substantial meal 2 hours
Relaxed as possible, seated 5-10 mins before
What are normal spirometry values?
FEV >80%
FVC >80%
FEV1/FVC - 70-80%
Hallmarks of obstruction
- Reduced FEV1/FVC ratio
- Reduced FEV1
- Increased exhalation time
- ate or no plateu on volume time curve
Hallmarks of restrictions
- Reduced FVC
- Normal or elevated ratio
- Reduced exhalation time
- Early plateu on volume time curve
Extrapulmonary causes of restrvitive disease
- Kyphoscoliosis
- Ankylosing spndylitis
- Lung volume reduction surgery
- Muscle weakness
Intrapulmonary causes of restrictive lung disease
- Pulomonary fibrosis
- Sarcoidosis
- Asbestosis
- Fibrosing alveolitis
What is peak flow a measure of?
- Measure of how FAST air out of lungs
- Large AW claibre measure
What normal values depend on in peak flow?
- Age
- Height
- Weight
Normally over 20%
What sort of conditions cause reduced PEFR?
OBSTRUCTIVE
Asthma, COPD, tumour
What use spirometry measure?
- Registers AMOUNT of air exhaled or inhaled
- RATE at which aire goes in and out lungs
- Forceful and complete exhalation after maximal inhalation
- FEV1/FVC/Ratio/trace itself
What does measuring FEV1/FVC pre and post bronchodilator measure?
(ideally held medication)
- Estimates degree of reversibility
- 10-15 mins after MDI SABA
What are the parameters for responsiveness to SABA on FEV1?
If FEV1 increases by 12% AD 200ml = responsive
What are the requirements for reproducibility of spirometry?
- Need the highest recording of 3 traces
- 2 highest FVC recordings within 0.15L of each other
- 2 highest FEV1 recordings within 0.15L of each other
What is FEV1 clinical use?
Determining severity of airflow obstruction of present and also in monitoring response to treatment/decline
What FVC clincial use?
- Indication lung volume
- If reduced → full PFTs
- If decreased + sus airflow obstruction → relaxed VC
What is the clinical use for FEV1/FVC ratio? Drawbacks?
- If Airflow obstruction is present
Negatives
- Not helpful for severity
- Fixed thresholds can lead to misclasification (classically <0/7 = obstruction)
- Normal can be normal OR restrictive disease
What is the FEV1/FVC in restrictive disease?
Normal
What is the normal decline in FEV1/FVC?
decline of 20-30ml/year
How to calculate relaxed vital capacity?
- FEV1/VC %
- Largest FEV1 / largest VC x 100
What is relaxed vital capacity?
Max volume expried from full inspiration, done at a steady orrelaxed pace
Where go for escalation?
- ITU
- HDU
- Coronary care unit - CCU
- Acute respiratory units - CPAP + BIPAP
Types of shock
- Distributive - warm and dry
- Cardiogenic - cold and wet
- Obstructive - cold and dry
- Hypovolaemic - cold and dry
Indications for emergency dialysis
AEIOU
- Acidosis <7.1 pH
- Electrolytes - refractory hyperkalemia K<6.5 mEq/L
- Intoxications
- Overload fluid refractory to diuresis
- Uremic pericarditis, uremic encephalopathy
Management for resp support
- Mechanical ventilatory support - CPAP, BIPAP
- Intubation
- Dialysis for oxygen - hypoxic despite ventilation
How to manage low BP in emergency
- Fluid bolus
- Blood
- Vasopressors - constrict vessels, increase BP
How to manage heart failure in emergency
- Balloon pumps
- Stent
- VD
- Vasoactive drugs
Where treat each level for emergencies?
Level 1 = ward treatment
Level 2 = deteriorated, need single organ support eg ARU, CCU,
Level 3 = advanced resp support - intubation or ventialtion, 2 or more organs failing
What is adenophagia?
Pain on swallowing
Clinical trajectory ITU
1) Early death
Dying on ITU - unconscious, can’t talk to relatives
2) Rapid recovery
3) Chronic critical illness
- Organ dysfunction
- Persistent Kidney Injury
- Neurocognitive decline
- Sepsis - induced myopahty - satellite cell dysfunction
- Persistent inflammation
- Immunosupression
- Catabolism
Drugs that cause kidney damage
INH, Isopropyl alcohol
Salicyclates
Theophylline, Tenormin (atenolol)
Uremia
Methanol
Barbituates
Lithium
Ethylene glycol
Dabigatran, Depakote
When use CPAP?
TI resp failure
How ween off intubation if not appropriate to go straight to breathing?
Tracheotomy
What is critical illness polyneuropathy and what does it cause?
Shocked = little blood supply to muscles and nerves, vasopressin → peripheral constrictions, poor blood supply
- Acquired channelopathies
- Pro-inflammatory imbalance
- Microvascular disruption
- Metabolic derangements
- Altered cellular bioenergy and mitochondrial function
- Alteration of gene expression
Why don’t escalate care?
Shocked = little blood supply to muscles and nerves, vasopressin → peripheral constrictions, poor blood supply
- Acquired channelopathies
- Pro-inflammatory imbalance
- Microvascular disruption
- Metabolic derangements
- Altered cellular bioenergy and mitochondrial function
- Alteration of gene expression
Medical futility at end of life - when?
- No clear attainable foal - not enhancing quality, rescuing or prolonging lige
- Pointless, not reasonable
- Burden > benefit - risks, actual harm, possible harm - size of benefit, likelihood of benefit
- Has to be defined with regard to individual patient holistically
Options if not escalated to ITU?
- Ward based care
- Limited escalation of care - CIPAP, BIPAPA, peripheral BP support
- DNACPRs
- Palliation - natural death is so important
When DNACPRs and what consider?
Legally binding, signed by F2 or above, consultant needs to sign too, but still valid without
Friends and family discussion
Every reasonable measure
How to make a dignified death?
- Human desire to help people
- Worst outcome is bad death
- Peacefuk and dignified
- Unnecessary or invasice treatment and diagnostics in days/hours of life
- Hurried/rushed conversations about end of life care in emotionally fraught circumsatnces, often without patient involvement
- Short window of time to fulfill preferences
- Hospital may become only viable location of deatg
- Symptoms of dying not adressed until late in dying process
ACS emergency treatment
- Antiemetic-metacorpramide - nausea
- Morphine
- Oxygen
- nitrates → vasodilation → increase perfusion to heart
- SC heparin
- STEMI ALWAYS → HOSPITAL
- NSTEMI sometimes reperfuse, context based
NEWS score parameters
NEW SCORE
NORMAL PARAMETERS
RR = 12-2-
HR = 60-100
BP = 120-140 systolic
Temp = 36-7.5
Spo2 >94% on RA
Level of consciousess = AVPU
urine output = 5ml/kg/hr, 30-50 ml/hr
What confusion levels deserve escalation?
P on AVPU or GCS 8
What anaemia does alcohol cause?
Macrocytic
What type of anaemia does iron deficiency cause?
Microcytic
What is used for the bleeding score for patients on anticoagulants in AF?
ORBIT
What is TLCO
KCO + alveolar volume
Decreased KCO +TLCO
emphysema
Increased KCO +TLCO
- Pulmonary haemorrhage - RBC are alreayd there
- Polycythaemia
- Shunts (L→R)
What is KCO + TLCO
Normal to raised KCO
decreased TLCO
What is KCO and TLCO a measure of
KCO = measure of blood per unit of lung
Restrictive = more blood per unit of lung
Obesity causes breathlessness due to increased workload of the chest wall, particularly when distributed in the abdomen.What might you expect to see on lung function testing and blood gas analysis?
Spirometry may be restrictive, with reduced FVC>FEV1. KCO should be normal or high. Blood gases could show a raised pCO2 and bicarbonate indicating compensated hypercapnia. The restriction is likely to be highest during sleep (effect of gravity on the obese abdomen) so pCO2 is most likely to be elevated in the morning.
An abnormally shaped chest wall e.g. due to kyphoscoliosis, limits chest wall expansion and therefore reduces ventilation
External pressure from air (pneumothorax) or fluid (pleural effusion) can cause breathlessness by reducing the lung’s ability to expand and increasing work for the diaphragm.What clinical findings might make you think of pleural disease?
[Pneumothorax and pleural effusion] A pneumothorax may present suddenly and be associated with chest pain; pleural effusion usually develops much more gradually.
On examination both will be associated with reduced breath sounds, but signs associated with a pneumothorax include hyperresonance to percussion and subcutaneous emphysema whilst pleural effusion causes ‘stony dullness’ on percussion and may be associated with fluid overload elsewhere e.g. oedema and ascites.
Radiology is your first line investigation!
Liver screen full
Coag screen
Serum albumin
Autoantibodies - ASMA, AMA, ANA, p-ANCA, LKA
Immunoglobulins
Anti-HBc - IgM, IgG
hb SaB
HB sAb
PBC - IgM
IAMA - IgG, A etc
Antibodies and antigens for hepatitis
Toxicology
Copper
transferrin saturation
Platelets
