High Airway Pressure Flashcards
What are the 3 broad causes of high airway pressure
- Patient factors
- Airway factors
- Circuit factors
List the potential CIRCUIT factors contributing to high airway pressure
- Ventilator bag switch
- Ventilator settings
- Obstructed, kinked circuit
- Filter blockage
- Circle valve malfunction
- APL valve closure or
- Stuck O2 flush malfunction
List the potential AIRWAY factors that may contribute to high airway pressure
- Laryngospasm (LMA)
- Tube position
- Tube size
- Tube obstruction
List the potential PATIENT factors that may contribute to high airway pressure
- Obesity
- Chest wall compression
- Chest wall rigidity
- Tracheal pathology
- Foreign body
- Laryngospasm
- Respiratory tract tumour
- Pneumothorax
- Bronchospasm
- AutoPEEP
- Alveolar pathology - oedema, fibrosis, contusion, infection, ARDS
- Pneumoperitoneum (inc intraabdo pressure)
What are the most COMMON causes of high airway pressure
- Inadequate muscle relaxation
- Airway position
- Laryngospasm
- Bag/Ventilator settings
What immediate management steps should be taken
- Switch to manual ventilation with a high FiO2
- Squeeze bag to confirm difficult ventilation
- If ventilation is easy - examine circuit for faults
- If ventilation is difficult - examine airway and pt first
What is involved in assessing the circuit for faults
- Quickly scan the circuit for any obvious issues - kinked or obstructed circuit
- Disconnect from the patient and confirm reservoir bag empties easily while disconnected AND while 2nd bag is attached
- Monitor recorded pressures while 2nd bag attached
Outline the process of assessing the airway and patient for possible causes
- Exclude light anaesthesia, coughing, biting on tube
- Exclude inadequate muscle relaxation
- Give Propofol bolus or NMB bolus if appropriate
- Assess tube/LMA position
- Remove, reposition or replace as necessary
- Pass suction catheter to assess patency
- Inspect the chest for movt, feel tracheal position, look for distended neck veins
- Look for possible rash
- Auscultate for wheezes/crackles
In what situations may high airway pressures be considered tolerable
Only when there is a definitive cause in keeping with the clinical scenario
Pneumoperitoneum, steep trendelenburg, obese patients, restrictive lung disease
What strategies may improve high airway pressures
Identify cause and correct as appropriate
Decrease tidal volume and/or resp rate
Increase I:E ratio closer to 1:1
Turn off PEEP
Avoid steep trendelenburg
Use PCV - need to check that minute ventilation is adequate
What other considerations should be taken into account when faced with high airway pressures
Is this autoPEEP - examine ventilator flow/volume loops
Perform inspiratory holds (in ICU) to ascertain compliance
Consider the timing -> recent drug dose (anaphylaxis), CVC placement (pneumothorax), tube adjustment or pt repositioning, pneumoperitoneum or surgical intervention
If patient is taken off circuit will need an additional means of maintaining anaesthesia
