Non-Invasive Ventilation Flashcards
Non-Invasive Positive Pressure Ventilation (NPPV) Definition
- The augmentation of alveolar ventilation thru means other than an artificial airway
- Can be:
- NPPV (BiPAP)
- CPAP - doesn’t augment patient’s ventilation
- Other methods of NPPV:
- Iron Lung
- Chest Cuirass
In What two acute care conditions is NPPV the standard first line of care
COPD Exacerbations-Reduce mortality, reduce hospital stay, fewer complication. Should only be used when they are not at risk for intubation (PaCO2 is >45 mmHg and pH is <7.35)
Acute Cardiogenic Pulmonary Edema- First line of therapy with CPAP of 8-12 cmH2O. If patient is hypercapnic or has persistent dyspnea then go to BiPAP
Acute Care Condition Where we can Use NPPV
Asthma- Only ancedotal evidence
Immuosuppresent State- Use NIPPV unless contradictions are present as there is a reduced rate of pneumonia and infections
Community Acquired Pneumonia- Reduce rate of intubation and length of hospital stay (only when patient has underlying COPD). As of right now only used with pt. wit pneumonia concurrent with COPD
Hypoxemic Respiratory Failure-Conflicting results in studies. If we are using it we need to see imporvement in 1-2 hours
Do-Not-Intubate-Orders-Use only if patients understand that it will only help the acute process and not the underlying chronic process
Postoperative-Some studies show positive results, especially prophylactic use for obese patients. Needs more studies
Difficultly Weaning-Shows reduced weaning, length of ICU stay, incidence of nosocomial pneumonia and 60 day mortality, however, duration of ventilator support was longer. Most benefit seen in acute on chronic (COPD) and CHF
For patients acute respiratory failure should have at least two of the following
Accessory muscle use
Paradoxical breathing
RR ≥ 25 bpm
Dyspnea
PaCO2 > 45 mmHg with pH < 7.35
PaO2 / FiO2 < 200
Chronic Care Indications
- Nocturnal Hypoventilation
- Eg. Sleep apnea, obesity-hypoventilation syndrome
- COPD
- Rest the respiratory muscles and improve sleep
- Restrictive thoracic disease
- Will rest respiratory muscles, decrease CO2 and improve lung function
- Types of restrictive thoracic disease
- Post polio
- Neuromuscular disorders
- Chest wall abnormalities
- Kyphoscoliosis
When a patient has acute respiratory failure contraindications for NPPV include
Apnea
Hemodynamic instability
Uncooperative patient
Facial burns
Facial trauma
High risk of aspiration
Copious secretion
Anatomic abnormalities
Predictors of NPPV success (Acute Setting)
Minimal air leak
Low severity of illness
Respiratory acidosis (PaCO2 > 45mmHg but < 92mmHg)
pH < 7.35 but > 7.22
Improvement in gas exchange within 30 – 120 minute
Improved respiratory rate and heart rate
Criteria for Terminating NPPV
Worsening pH and CO2
RR > 30 bpm
Hemodynamic instability
Inability to clear secretions
Decreased LOC
CPAP
Spontaneous unsupported breathing
Does not augment ventilation
NPPV
Spontaneous supported breaths with 2 pressure levels
Does augment ventilation
Home care ventilators or critical care ventilators provide NPPV
BiPAP is a general term derived from one of the first NPPV machinesOften used in the context of any non-invasive mode that augments ventilation
EPAP and IPAP
Most common equivalent is to pressure support ventilation
Expiratory Positive Airway Pressure (EPAP)
- aka CPAP when no inspiratory pressure is used
- Physiological Effects:
- Reverses atelectasis
- Recruits alveoli (improve V/Q)
- Increases FRC
- Improves compliance
- Can offset the effects of intrinsic PEEP
- Causes mechanical bronchodilation, decreasing airway resistance
- All of the above will decrease WOB
Inspiratory Positive Airway Pressure (IPAP)
- IPAP is the analogous to the Pressure Support setting in PSV
- Like in PSV the resulting VT is dependent on pt effort, lung mechanics and the amount of support set (IPAP/PS)
- However, these pressures are typically set as an absolute pressure on non-invasive ventilators
- Physiological Effects:
- Reduces WOB
- Relieves respiratory muscle fatigue
- Augments patient’s own spontaneous efforts thereby improving spontaneous tidal volume
All of the above will decrease WOB
Spontaneous (S) Mode
Patient triggered, pressure limited, flow cycled
No mandatory breaths
Spontaneous/Timed (S/T) Mode
Patient triggered breaths are P limited and flow cycled
Time triggered breaths are P limited and time cycled
Often (depending on the machine) mandatory breaths are only given if the patient’s rate falls below the set rate
Timed (T) Mode
A control mode: time triggered, pressure limited, time cycle