Non-Invasive Ventilation Flashcards
Aims of NIV
improve gas exchange via improved ventilation
avoids need for ventilatory support
augment patient’s spontaneous respiratory effort
modify a patient’s respiratory activity
reduced work of breathing
rest patient’s respiratory muscles
prevent large increase of noctural O2 levels
improve underlying pathophysiological changes
allow time for reversal of acute cause or respiratory failure
aid mobilisation of secretions
improve quality of life
What impairments is NIV relevant for?
respiratory muscle dysfunction reduced lung volumes impaired airway clearance impaired gas exchange airflow limitation musculoskeletal dysfunction
Spontaneous NIV
patient triggers all breaths
control their own RR and pattern
machine provides assistance with inspiration once the patient initiates it
Spontaneous/Timed NIV
patient triggers breath
set time - if breath isn’t triggered, machine will instigate breath
Timed NIV
all breaths controlled by the machine
IPAP vs EPAP
PAP - any respiratory pressure above atmospheric pressure
IPAP - inspiratory positive airways pressure, supports inspiration
EPAP - expiratory positive airway pressure, supports expiration
PEEP
positive end expiratory pressure - positive airway pressure is at the end of expiration only
When FRC is reduced - forces the airways to stay open at the end of expiration
BiPAP
bilevel/biphasic positive airway pressure
combine separate IPAP and EPAP settings to support both inspiration and expiration
different pressure on inspiration and expiration
IPAP - increases tidal volume
- results in increased minute ventilation
- results in increased PaO2 and decreased PaCO2
- decreases work of breathing
EPAP - splints open upper airways during expiration
- increases FRC
- decreases WOB
- decreased FiO2 requirements
- overcomes intrinsic PEEP
Indications BiPAP
Type 2 respiratory failure airflow limitation alveolar hypoventilation neuromuscular disease avoid mechanical ventilation patient not suitable for invasive ventilation weaning from mechanical ventilation facilitate exercise in extremely SOB patients
CPAP
continuous positive airway pressure provides a constant level of airway pressure over which the patient maintains their normal breathing splints open upper airways - increases FRC - recruits collapsed alveoli - maintains higher lung volumes - enhances lung compliance and gas distribution - improve oxygenation reduced WOB reduced FiO2 requirements
CPAP Indications
Type 1 respiratory failure
- reduced FRC due to atelactasis, sputum retention and anesthesia
- airway oedema
- airway obstruction
- pneumonia
- inhalation born injury
- asthma
- avoid mechanical ventilation
- patient not candidate for invasive ventilation
- weaning from mechanical ventilation
- flail chest - splints the flail segment open
- sleep disordered breathing
NIV Precautions/Contraindications
haemodynamic instability unstable multi-organ failure uncooperative or unmotivated patients increased risk of aspiration inability to effectively clear secretions vomiting upper GI surgery unstable facial fractures extensive facial lacerations or burns CSF leak untreated pneumothorax inability to fit an acceptable mask inadequate social/home support establish end point of care
NIV Potential Complications
gastric distension aspiration decreased cardiac output pulmonary barotrauma facial pressure areas patient discomfort nasal obstruction pneumocephalus - presence of gas in the cranial cavity
What do we need to monitor in patients with NIV?
SpO2 ABGs RR, tidal volume, breathing pattern synchronisation mask pressure and leak conscious state and sleep state subjective and observed improvements
Role of Physio
assess patients whether NIV suitable implements NIV review once established and any troubleshooting use NIV as adjunct to other treatment airway clearance exercise
