hyperinflation and suctioning Flashcards
hyperinflation
giving a patient an augmented tidal volume via manual bag or ventilator to a patient with an artificial airway
manual vs ventilator delivered
ventilated critically ill patient
increase sputum tracheal membrane irritation impaired mucociliary clearance decreased cough+ ciliary clearance loss of compliance loss of sigh breaths progresive atelectasis
indications
prevention and treatment of atelectasis mobilisation of retained secretions assess and increase lung compliance stimulate FET improve gas exchange improve oxygenation pre/post suction
precautions /CI
CI undrained PT head injury ICP >25mmhg bronchopleural fistula lung abscess bullae
Precautions unstable CV system high PEEP nitric Oxide dependency high peak airway pressure raised ICP and head injuries severe bronchospasm /wheeze high fiO2 requirements acute pulmonary oedema haemoptysis pressure control ventilation recent lung surgery lung abscess
MHI technique
patient disconnected from ventilator and given an altered breathing pattern
slow inflation flow rate
larger than tidal volume breath
end-inspiratory hold to utilise collateral ventilation channels
quick release to enhance expiratory flow rate
interspersed with tidal volume breaths
equipment
2L bag for adults mapleson C-circuit O2 flow 15 Ipm peak insp pressure 30-40cm not over 40 as risk of barotrauma
how does it aid secretion clearance
increase TV increases elastic recoil and hence increase exp flow rates
quick release produces a fast expiratory flow mimicking a cough
uses CV channels
bronchiole=alveolar channels of Lambert
idntraalveolar pores of Kohn
can recruit air distal to a mucus plug which can help propel it into more proximal airways
how does it aid lung recruitment
MHI
Slow, sustained inspiration
Low inspiratory flow
P = Flow Resistance
Allows better distribution of gas to slow filling lung units
Inspiratory Hold utilises collateral ventilation
Increased tidal volumes
Interdependence: Expanding force one alveoli exerts on neighbouring alveoli (greater stretch 2° greater pressure)
how does it improve gas exchange MHI
increase TV + longer inspiratory time = increase gas exchange
MHI - how does it increase compliance
alveolar recruitment
increase FRC
increased compliance
(lungs more stretchable)
treatment regime
based on tolerance response and efficacy of modality
6 sets of 6 hyperinflation breaths with 30s TV breaths between each set
latent effects
Monitor SaO2, BP, HR etc
Document values pre- and post- treatment
Notify nursing staff before leaving the area if manual hyperinflation is performed
Check prior to next treatment for latent effects and stability
VHI define
Definition: VHI involves altering the ventilator settings to gradually increase tidal volume (Imle & Klemic 1989)
Proposed to produce the same effects as MHI whilst controlling airway pressures and maintaining PEEP (Brown 1987)
changing pressure or volume or insp time
can add in inspiratory hold
VHI method
gradually increase TV by 50% but peak airway pressures should be limited to 40cmH2O
MHI VHI
MHI disconnection P reg by valve mimic FET assess compliance
VHI no disconnection/ PEEP maintained V/P controlled by vent no FET unable to assess compliance possibly less secretion removal easier to control Airway pressures
