Lecture 7 Flashcards
What is the mechanism of action behind specific positioning and postural drainage?
- gravity opens airspaces by passively stretching the lung
- increases stretch = increased surfactant production - reduced surface tension
- increased compliance of lung portion that was placed upper most - i.e reversed atelectasis
What factors are CI/P’s to HDT?
- MAP < 6-65
- BP variability
- arrythmias
- tachy/bradycardia
- hypovolaemia
- inotrope requirement
What’s more effective for sputum clearance - side lying + MHI or HDT + MHI in CV stable pts?
HDT+MHI
What are CIs/P’s to positioning?
Spinal Cord injury Skeletal traction Acute brain injury (i.e change in ICP) Craniotomy Rib # UWSD (can turn pt onto chest drain side - but monitor to see the drain amounts not affected) Cardiac disease (arrhythmias)
Define manual hyperinflation and what do Berney et al (2004) recommend as a dosage for MHI/VHI
The delivery of a larger than normal tidal breath (1.5-4x normal Vt) with an anesthetic or resuscitation circuit
6 sets of 6 breaths
What are the different types of MHI circuits?
Laerdal circuit - 1.6L capactiy; resuscitation circuit; works with or without oxygen
- Mapleson C - more secretions cleared with this circuit
- Mapleson F - this is what we use - 2L capacity
- PEFR greater with mapleson circuits
What is the rationale for gas/secretion movement in MHI?
Deep breath = increased volume - surfactant production- reduced surface tension and better compliance
Slow inspiration = reduces effect of airway resistance on ventilation distribution
Inspiratory hold = collateral ventilation
Rapid release for expiration = aids secretion clearance - but expiratory flow has to exceed inspiratory flow by 10% (velocity 1000 cm/sec)
What are the benefits of MHI?
- pulmonary compliance (deep breath)
- arterial oxygenation (hold)
- clearance of airway secretions (fast expiratory flow)
- prevents/treats atelectasis (deep breath/hold)
What is the benefit of VHI over MHI for decruitment?
Since VHI doesn’t require disconnection from the ventilator - PEEP can be maintained and this avoids potential de-recuitment of alveoli
What parameters can you monitor during MHI and WHEN do you monitor?
- before, during, after
- SpO2
- HR/BP/MAP/ECG
- Airway pressures (<40 for MHI; <20kpa for suction)
- EtCO2
- Ausc pre/post
MHI - what are the precautions and modifications for an unstable respiratory system?
Precautions:
- PEEP > 10cmH2O
- FiO2 > 0.6
Mods:
- Use PEEP valve
MHI - what are the precautions and modifications for an unstable cardiovascular system?
Precautions:
- hypotension
- brady/tachycardia
Mods:
- smaller volume - slowly increasing size of breath
- intersperse big/small breaths
- encourage spontaneous effort
- no hold
- ensure complete expiration - no PEEP
all this reduces the positve pressure on the venous channels with improves venous return to the heart
MHI - what modifications would you make for:
- Stiff lungs (ARDS eg)
- Hyperinflated pts
- Raised ICP
- Slow inspiratory flow rate/pressure manometer
- Ensure complete expiration (no PEEP)
- Pressure manometer - keep <40 cmH20
When do you know to suction a patient?
- Visible, audible, palpable secretions
- Respiratory signs:
- desat, increasing PIP, increased WOB, increased RR, decreasing Vt, coarse crackles - Cardiovascular
- increased HR/BP - Individual
- sweaty (diaphoretic), restless, agitated - Ventilator graphics
- saw tooth pattern
What does a normal ventilator graphic look like? What does a saw tooth pattern indicate?
Normal graphic - triangular in shape, 80% expired in 1 second
Saw tooth pattern indicated condensate build up or loose secretion build up
