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
What are respiratory hazards of suctioning?
- Hypoxia
- Bronchospasm
- Damage to trachea/bronchial mucosa
- Atelectasis
- Reduction in lung compliance/FRC
What are cardiac hazards of suctioning?
Increased and decreased BP
What are neuro hazards of suctioning?
Increased ICP
Changes in cerebral blood flow
Saline is not recommended for routine use prior to suctioning. What factors can you optimise prior to using saline?
HHMM
- Humidification
- Hydration
- Mobilisation
- Mucolytics
What are adverse effects of hyperinflation?
- Increase/decrease:
- MAP
- Q
- PAP
- Paw
When is above the cuff suction used and what are it’s benefits?
When ventilated > 72 hrs
Benefits:
- reduced ventilatory assoc pneumonia (VAP)
- reduced ICU LOS
- reduced MV
What is ICU acquired weakness?
- seen in 25-60% of MV pts who are ventilated > 1 week
- diffuse symmetric generalized mm weakness
- unclear etiology
What are the benefits of early mobilisation?
- peripheral mm strength
- resp mm strength
- physical fxn indices
- HRQOL
- LOS in ICU
