Respiratory Flashcards
Empyema: medical and surgical management
Supportive:
* Supplemental O2
* Analgesia
* Fluids/nutrition (considering SIADH / catabolism etc)
Specific (Medical):
* IV Abs Broad Spectrum (Piperacillin-Tazobactam or Cefotaxime + Vancomycin if MRSA
suspected)
* Once sepsis settled and stabilised, 3-4 weeks of PO ABx (usually AugDF)
* Large Bore Chest drain (large size) ~20Fr
Specific (Surgical Options):
* Fibrinolytics via chest drain
* VATS – video-assisted thoracoscopic surgery
* Open thoracotomy
Biochemical features on pleural fluid of empyema
Purulent pleural fluid
1 or more of following:
* + gram stain / culture
* WCC > 50,000
* Pleural fluid glucose <3.3
* Pleural fluid pH <7.2
* Pleural fluid LDH >1000
PE definitions: massive, submassive, non-massive
Massive PE
Acute PE + haemodynamic compromise (no longer defined by size)
* BP < 90 for 15min
* Vasopressor requirement
* Pulseless
Submassive PE
Acute PE, not haemodynamically compromised but:
* Right heart strain (ECG / Echo / BNP)
* Troponin Leak
Non-massive PE
Acute PE + none of above
Well’s Score (and simplified Well’s) for PE
PERC rule components + interpretation
Parameters at initial ED assessment (8 components)
- age <50 years
- HR < 100 beats/min
- SpO2 > 94% on air
- no unilateral leg swelling
- no haemoptysis
- no surgery or trauma within 4 weeks
- no previous DVT or PE
- no oral hormone use
*if all the above criteria are met
- sensitivity for PE detection is approximately 95%, speciificity 10%
- post test probability of PE is 0.4 - 3% for PE (LR- 0.17)
- may not be quite sensitive enough to make decisions about need for further testing
- HR of > 100 present in only 40% of patients with PE, so this criteria will miss a significant proportion of patients
Echo findings in PE
- RV
- > 2.5cm in PLAX view in absence of hypertrophy
- McConnell’s sign: RV apical free wall normokinesia +/- hyperkinesia despite akinesia +/- hypokinesia of remaining RV free wall
- D-shaped inter ventricular septum
- Tricuspid regurgitation
- Tricuspid annular peak systolic excursion at free wall annular excursion (TAPSE) < 1 cm on M mode Ap4Ch or subcostal views
- Small LV with change in size with respiration
- Intracardiac thrombus (rare) +/- PFO
- Non-collapsable IVC
- Elevated pulmonary artery pressure
In simple terms:
- Dilated RV
- Poorly contractile RV
- Hyperdynamic LV
- Dilated IVC
- McConnell sign (RV RWMA sparing RV apex)
- Bowing septum to LV
Pulmonary hypertension aetiology groups (I-V) and examples
Group I - pulmonary arterial hypertension
*uncommon
*idiopathic (primary)
*familial
*drug use
-cocaine
-amphetamines
Group II - pulmonary venous hypertension
*second most common cause
*left-sided atrial or ventricular heart disease
*left-sided valvular heart disease
Group III - associated with chronic hypoxaemia
*most common cause
*chronic obstructive pulmonary disease etc
Group IV - chronic thromboembolic disease
Group V - miscellaneous
*sarcoidosis
*pulmonary Langerhans’-cell histiocytosis
*lymphangiomatosis
*systemic sclerosis
* tumour obstruction
* chronic renal failure on dialysis
Pulmonary hypertension - treatment
Mild-moderate disease
- Supplemental oxygen
- Vasodilators
* Sildenafil 80mg TDS improved ~60% patients
* CCBs useful in ~10%
- Diuretics
- Anticoagulation (idiopathic and secondary to VTE)
Severe cases:
Epoprostenol
- Vasodilator with antiplatelet and anti-inflammatory effect
Bosentan/Sitaxetan/Ambrisentan
- Endothelin-receptor antagonists
- Vasodilatory, anti-inflammatroy agents
- Remodelling mediator
Ambrisentan
- Selective antagonist of endothelin type A receptor -> blocks vasoconstrictive effects of endothelin (produced by endothelial cells)
- SEs incl. hepatotoxicity, peripheral oedema, nasal congestion, sinusitis, flushing, palpitations, anaemia
- 5-10mg film-coated tablets
Indications and dose of thrombolysis in massive PE
- Cardiac arrest from suspected PE
- High risk PE with cardiogenic shock +/- persistent hypotensive OR persistent hypoxia with respiratory distress unresponsive to maximal O2 therapy
- Right heart strain on echo, or cardiac markers (PEITHO study) OR
Moderate PE (right and left main pulm trunks or > 2 lobes with >70% involvement) (MOPPETT study)
Alteplase
1. 10mg bolus followed by 40-90mg IV over 2 hours
2. 50mg IV bolus in cardiac arrest (prolonged CPR)
Contraindications to thrombolysis in PE
- CNS
- Heamorrhagic CVA (absolute)
- Ischaemic CVA <3 mo (absolute)
- Ischaemic CVA >3 mo (relative)
- Structural cerebrovascular disesase i.e. AVM (absolute)
- CNS neoplasm (absolute)
- CNS surgery <3 mo (absolute) - Trauma
- Recent head trauma with fracture or brain injury (absolute)
- Minor head trauma due to syncope NOT contraindication - Recent surgery/procedures
- Major non-CNS surgery <3wk (relative)
- Recent puncture of non-compressible vessel (relative) - Bleeding history
- Active bleeding, excl. menses (absolute)
- Recent internal bleeding <2-4 wks (relative)
- Known bleeding diathesis (absolute) - Coagulation studies
- Plt <100 (relative)
- Elevated INR, PTT (relative) - Anticoagulants
- Oral anticoagulation (relative)
- Multiple anticoagulants (relative) - Hypertension
- History of chronic, severe, poorly-controlled HTN (relative)
- BP on presentation >180 systolic or >110 diastolic (relative) - Age
- >75yo (relative)
- Dementia (relative) - Special populations
- Pregnancy or 1st week postpartum (relative)
- Traumatic or prolonged CPR (relative)
Initial ventilator settings in intubated paediatric asthma patient
Dose of second- and third-line asthma treatments
IV steroids
- IV hydrocort 4mg/kg (max 200mg)
- IV methylpred 1mg/g (max 60mg)
- IV dex 0.6mg/kg (max 16mg)
MgSO4 - 0.2mmol/kg (max 8mmol)
Aminophylline - 10mg/kg (max 500mg) over 30 mins (not compatible with MgSO4)
IV salbutamol - 5-15 microg/kg (max 300 microg) over 10 mins -> infusion 1-2microg/kg/min (max 200microg/min), adjust to response and HR
IM adrenaline 10microg/kg of 1:1000 (max 300 microg; 500 microg in adults), repeated 5 minutely, as required
ECG findings in PE
● Sinus tachycardia – the most common abnormality; seen in 44% of patients.
● Complete or incomplete RBBB – associated with increased mortality; seen in 18% of patients.
● Right ventricular strain pattern – T wave inversions in the right precordial leads (V1-4) ± the inferior leads (II, III, aVF). This pattern is seen in up to 34% of patients and is associated with high pulmonary artery pressures.
● Right axis deviation – seen in 16% of patients. Extreme right axis deviation may occur, with axis between zero and -90 degrees, giving the appearance of left axis deviation (“pseudo left axis”).
● Dominant R wave in V1 – a manifestation of acute right ventricular dilatation.
● Right atrial enlargement (P pulmonale) – peaked P wave in lead II > 2.5 mm in height. Seen in 9% of patients.
● SI QIII TIII pattern – deep S wave in lead I, Q wave in III, inverted T wave in III. This “classic” finding is neither sensitive nor specific for pulmonary embolism; found in only 20% of patients with PE.
● Clockwise rotation – shift of the R/S transition point towards V6 with a persistent S wave in V6 (“pulmonary disease pattern”), implying rotation of the heart due to right ventricular dilatation.
● Atrial tachyarrhythmias – AF, flutter, atrial tachycardia. Seen in 8% of patients.
● Non-specific ST segment and T wave changes, including ST elevation and depression. Reported in up to 50% of patients with PE.
Causes for false negative D dimer in PE
- Small clot loat (e.g. small calf only DVTs)
- Mature thrombus
- Defective fibrinolysis (contributory to formation of initial thrombus also)
Methods for estimating size of pneumothoraxx
Light’s formula
* horizontal distance from the midline at the level of the hilum to the outer edge of the pneumothorax cubed
* divided by the horizontal distance from the midline at the same level to the lateral chest wall cubed
British Thoracic Society guidelines
* size of a pneumothorax is divided according to presence of visible rim between lung margin and chest wall at the level of the hilum on a PA CXR
- small - visible rim < 2 cm
- large - visible rim ≥ 2 cm
* a 2 cm pneumothorax is approximately 50% (‘large’)
American College of Chest Physicians
* size determined by distance from the lung apex to the ipsilateral thoracic cupola at the parietal surface as determined by an upright standard CXR
- small - apex to cupola distance < 3 cm
- large – apex to cupola distance ≥ 3 cm
Features on history of poor asthma control
1) Daytime symptoms >/= 2 days per week
2) Need reliever > 2 days per week - increased use of bronchodilators reported by patient/carer
3) Any limitation of activities
4) Any symptoms during night or on waking
5) >3 or 3rd presentation to ED in 1 month
6) Prior ICU admission
7) Poor social situation / health literacy / concordance / compliance
NIV in asthma: pros and cons
Pros:
● Extrinsic PEEP decreases the work of breathing by helping overcome Auto-PEEP
● Extrinsic inspiratory positive pressure (IPAP) may increase tidal volume by decreasing the work done against airway resistance
● Shorter inspiratory times may increase tidal volumes without causing any extra dynamic hyperinflation
● NIV may prevent intubation in a select group of patients
● Decreases WOB
Cons:
● May delay intubation
● Inappropriate settings may increase the effort of breathing
● Increased positive airway pressure increases risk of pneumothorax
● Barotrauma
● Addition of extrinsic PEEP which is higher than
intrinsic PEEP will exacerbate dynamic
hyperinflation
● NIV makes it more difficult to clear secretions if
there is a strong infective component.
Chest xray - 30F w/ Goodpastures - differentials
- Pulmonary Haemorrhage (goodpastures)
- LRTI ie staph pneumonia, influenza
- Opportunistic infection (immunosuppressed) – ie Pneumocystis
- Cryptogenic Organising Pneumonia/ Bronchiolitis Obliterans Organising Pneumonia
- Congestive Cardiac Failure
- Malignancy with lymphatic dissemination ie Lymphangitis Carcinomatosis
Causes of pleural exudate?
- Infective – pneumonia, tuberculosis
- Inflammatory - rheumatoid arthritis, SLE, Dressler’s syndrome
- Malignancy
- Pulmonary embolism
- Benign asbestos related
- Abdominal – Pancreatitis, intra abdominal abscess, oesophageal perforation, ascites e.g. Meig’s syndrome (benign ovarian tumour/ascites/pleural effusion)
Risk factors for re-expansion pulmonary oedema post-thoracocentesis + ways to mitigate
- Age < 30 years
- Lung collapse for > 7 days
- >3 L pleural fluid
- Use of suction
- Rapid drainage >1.5L/hr
- Larger pneumothoraces
Possible prevention measures:
- Drain < 1.5 L pleural fluid initially or slow drainage to 500 mL per hour
- Avoid high negative intrapleural pressures (e.g. avoid suction in initial treatment)
Contra-indictaions to NIV in ED
- Unable to protect own airway
- Uncooperative
- Absent, weak, or agonal respiration
- Excessive respiratory secretions
- Maxillofacial fractures
- Basilar skull fractures
- Recent upper airway surgery
- Active vomiting
Lights Criteria for pleural exudate
Lights criteria (High protein and LDH = exudate), determines presence of exudate with protein and LDH levels
1. Pleural fluid protein to serum protein ratio >0.5
2. Pleural fluid LDH to serum LDH ratio >0.6
3. Pleural fluid level >2/3 of upper value for serum LDH
4. Pleural fluid albumin >30g/L
5. (optional) Serum albumin - pleural fluid albumin <1.2g/dL (confirms if results equivocal)
Causes of pleural exudate
- Malignancy – Lung, breast, pleural.
- Infection – Pneumonia, empyema, pleuritis, viral disease
- Autoimmune – Rheumatoid, SLE
- Vascular – PTE
- Cardiac – Pericarditis, CABG
- Respiratory – Haemothorax, Chylothorax
- Abdominal – Subphrenic abscess
Causes of pleural transudate
- Cardiac – CCF, PTE
- Liver – Ascites, Cirrhosis
- Renal – Glomerulonephritis, Nephrotic syndrome
- Ovarian – Meigs syndrome
- Autoimmune – Sarcoid
- Thyroid – Myxoedema
CXR - 1yoM, witnessed choking episode - describe findings and diagnosis (side)
Inhaled foreign body LEFT main bronchus
- Mediastinal shift to the right on expiratory
- Increased lucency on left lung on expiration
- Hyperexpansion left lung on expiration
- Normal inspiratory film
CXR - 30M IVDU - Describe xray and differential
- Cavitating lesion RMZ
- RML-LL consolidation
- Air bronchogram
- Small right pleural effusion
- Fluid in horizontal fissure
DDx.
Infective:
- Staph aureus
- TB/mycoplasma
- Anaerobes (peptostreptococcus etc.)
- Gram negs: klebsiella/legionella/pseudomonas etc.
- Strep pneumo
- Fungal, cryptococcosis, parasites, PJP
Non-infectious:
- Malignancy (primary, metastatic, lymphoma)
- Vascular incl. pulmonary infarction, VTE
- Granulomas (RA, sarcoidosis, Wegener’s)
- Pneumoconiosis, bronchiectasis
- Congenital cyst
CXR: 80M acute pleuritic chest pain, SOB BG smoker - CXR findings and DDx
- Marked hyperinflation
- Moderate/large left-sided pneumothorax
- Mediastinal shift to the right –
possible tension PTX - Bilateral widespread pulmonary infiltrates
- Right midzone (basal segment of upper lobe) wedge-shaped cavitating lesion/consolidation
- Right apical focal consolidation
- Interposed hepatic flexure under right hemidiaphragm (Chilaiditi syndrome)
DDx.
* Cavitating pneumonia – Klebsiella, S. Aureus, Pneumoccocus, TB
* Malignancy – primary bronchogenic CA
* Interstitial pneumonitis - Influenza/viral
* Pneumothorax – rupture of large bullae
