respiratory failure dr svitlana zhelezna clinical teaching fellow uhcw nhs trust...
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Respiratory Failure
Dr Svitlana ZheleznaClinical Teaching Fellow
UHCW NHS Trustsvitlana.zhelezna@uhcw.nhs.uk
2013/2014 academic year
Learning objectives:
Describe the clinical features, potential causes and management of respiratory failure
List indications/contraindications/complications of non invasive ventilation and understand its set up and monitoring
Definition:
Acute respiratory failure occurs when pulmonary system is no longer able to
meet the metabolic demands of the body
Type 1 Respiratory Failure Hypoxaemic
pO2 < 8 kPa ON AIR pCO2 < 6.0 kPa
Type 2 Respiratory FailureHypercapnic
pO2 < 8 kPa ON AIR pCO2 > 6.0 kPa
Clinical signs:
1. Respiratory compensation Tachypnoea Accessory muscles Recession Nasal flaring
2. Sympathetic stimulation HR BP (early) sweating
3. Tissue hypoxia Altered mental state HR and BP (late signs)
4. Haemoglobin desaturation:
(SpO2 < 90%)
Case 1 70 year old man referred to A&E by his GP PC: SOB and productive cough 4/7 HPC: gradual onset over 4-6/12 but worse over the last
3-4 days. SH: smoking 30 pack years.
O/E: O2 sats are 91% on air, RR 26, temp 37.8, BP 130/75, HR 89. Pt’s chest shows widespread bilateral wheeze throughout, reduced air entry LLL.
1. List your differential diagnosis and investigation tests.2. What would be your initial management of this patient?
ABG:
pH 7.31
pO2 8.4 kPa (on 6L O2)pCO2 5.9 kPa, HCO3- 21 mmol/l
Lac 3.1
What is your interpretation?
Initial management:
Investigations: ABG FBC, U&E, LFTs Peak flow CXR ECG Sputum and Blood
culture Urine dip, Urine
Microscopy
Treatment: A-E - Sepsis! Oxygen – high flow
initially, considercontrolled to aim O2Sat88-92% when stable
Nebulised bronchodilators
Steroids Antibiotics Fluids
COPD – Background:
Definition: COPD is predominantly caused by smoking and is characterised by airflow obstruction that: is not fully reversible and is usually progressive in the long term
COPD acute exacerbations: Increasing dyspnoeaIncreasing sputum volumeIncreasing sputum purulence (change in character)
Differentiating COPD from asthma
Clinical features COPD Asthma
Smoker or ex-smoker Nearly all Possibly
Symptoms under age 35 Rare Often
Chronic productive cough Common Uncommon
Breathlessness Persistent and progressive Variable/Intermittent
Night time waking with breathlessness and or wheeze
Uncommon Common
Significant diurnal or day to day variability of symptoms
Uncommon Common
Asthma – Background:
More than one of the following symptoms: Wheeze, cough, difficulty breathing, frequent and
recurrent chest tightness, worse at night and in the early morning;
Occur in response to, or are worse after, exercise or other triggers,
Personal/ Family history of atopic disorder and/or asthma
Widespread wheeze heard on auscultation History of improvement in symptoms or lung
function in response to adequate therapy.
Severe Asthma LIFE THREATENING PEF <33% best or predicted SpO2 <92% PaO2 <8 kPa normal PaCO2 (4.6-6.0
kPa) silent chest cyanosis poor respiratory effort arrhythmia exhaustion, altered
conscious level BP low
NEAR FATAL Raised PaCO2 and/or
requiring mechanical ventilation with raised inflation pressures
Criteria for Referral to ITU
Refer any patient: requiring ventilatory support with acute severe or life threatening asthma, failing to respond to therapy, evidenced by:
- deteriorating PEF
- persisting or worsening hypoxia
- hypercapnea
- ABG analysis showing low pH
- exhaustion, feeble respiration
- drowsiness, confusion, altered conscious state
- respiratory arrest
Case 2 17 y.o. female student PC: severe SOB, can not speak in full sentences HPC: woke up at 4 am feeling SOB and started
coughing, her housemate called ambulance PMH: too breathless to give O/E: Pt agitated, wide spread audible wheeze bilaterally,
poor chest expansion, using accessory muscles, HR 100, BP 130/85, T 36,6, O2 sat 93%
What would be your differential diagnosis and initial management?
ABG:
pH 7.46pO2 8.2 kPa (on 15L O2)pCO2 2.8 kPa, HCO3- 18 mmol/l
What is your interpretation?
Initial Management
Oxygen – high flow 15LNebulised bronchodilators Peak flowABGFBC, U&E, LFTs, Steroids
Case 3 76 year old male PC: SOB, 7/7 productive cough with phlegm PMH: known COPD, LTOT at home 2L for 16/24. On admission: RR 18, sats 85% on 2L oxygen,
HR 110, BP 134/68, temp 38.5. RLL crackles, but widespread wheeze throughout both lung fields.
The paramedics gave him 5ml salbutamol nebs and 100mg IV hydrocortisone an hour ago, he was given IV abx first dose, but he is not improving as yet, but become drowsy
What would be your management?
ABG: pH 7.23pO2 8.3kPapCO2 8.4kPa, HCO3- 24 mmol/lLac 4
Vitals:RR 12O2 Sats 90% on 4L oxygenHR 115BP 115/68
FBC:
Hb 16 g/dL
WCC: 18 × 109 /L
Neutrophils 80%
U&E:
Na 143 mmol/
K 4.6 mmol/L
Creat 120 μmol/L
Urea 8.2 mmol/L
What next?
Continue Nebulised Salbutamol
NIV (non-invasive ventilation)
NIV – non-invasive ventilation
Definition: Definition:
NIV is the delivery of mechanical NIV is the delivery of mechanical ventilation to the lungs using ventilation to the lungs using techniques that do not require an techniques that do not require an endotracheal airwayendotracheal airway
Types:
Continuous Positive Airway Pressure CPAP
Treating Hypoxia Type 1 RF
Bi-level Positive Airway Pressure (VPAP/Stellar)
Treating Hypercapnia Type 2 RF
Main goals of NIV
Correction of abnormalities in ABG’s (hypoxia and hypercapnia)
Maintaining alveolar ventilation and lung volume
Reduce the work of breathing Avoiding respiratory muscle fatigue
NIV does not correct underlying disorder or condition!
Medical conditions/Indications:
Acute exacerbation of COPD
(pH 7.26 – 7.35 or patients with NIV as ceiling of care and considered not suitable for HDU/ITU care)
Morbid Obesity / Severe OSA / Alveolar Hypoventilation Syndrome
Chronic Neuromuscular Disease Kyphoscoliosis / Chest wall deformity.
NIV contraindications: Respiratory arrest Undrained pneumothorax Impaired consciousness/confusion/aggressive
behaviour Chest wall trauma Uncontrolled vomiting/distended abdomen/
excessive secretions Facial trauma/surgery, burns or facial abnormalities
that are likely to cause difficulty with appropriate mask fit.
Recent upper abdominal surgery or intestinal obstruction.
Starting NIV: Locations:
HDU/ITU, Respiratory ward A+E resus (Not usually on a general ward – the nursing staff will not know how to deal with it)
Settings: • Should be prescribed by a consultant
Monitoring NIV:
Main actions:• Baseline ABG, RR, HR• Repeat ABG after one hour of starting• After every setting change, repeat ABG at 1 hour• Otherwise, every 4 hours, or if not well
Key points:• Aim minimum 6 hours treatment• Most people better by 24 hours on NIV• Weaning thereafter
Complications of NIV:
Pneumothorax, Decreased pre-load – may drop BP Increased risk of aspiration Face mask discomfort Anxiety + confusion
Key message
Common contributors to RF Type 1 (↓O2): Asthma and COPD Type 2 (↓O2 and ↑CO2): COPD and life
threatening asthma
NIV is effective in treating ↑CO2
Summary
worry if RR > 30/min (or < 8/min) unable to speak 1/2 sentence without pausing agitated, confused or comatose cyanosed or SpO2 < 90% deteriorating despite therapy
remember normal SpO2 does not mean severe ventilatory
problems are not present
Thank you!
Any questions?
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