Non Invasive Positive Pressure Ventilation

what is non-invasive ventilation (NIV)

what is another term for non-invasive ventilation

NIPPV

when is NIPPV indicated

in acute and chronic respiratory failure and obstructive sleep apnea

how does CPAP work

it delivers a constant positive pressure while the patient breathes spontaneously

what types of conditions can CPAP be used for

acute respiratory failure, cardiogenic pulmonary edema, and most commonly obstructive sleep apnea

how does CPAP help in obstructive sleep apnea

it acts as a splint to keep the upper airway open

what physiological criteria may indicate acute respiratory failure requiring intervention

PaCO2 greater than 45 mmHg, pH less than 7.35, and PaO2 to FiO2 ratio less than 200

when is NIPPV used in chronic ventilatory failure

when intubation is not an option

what PaCO₂ level indicates chronic ventilatory failure for NIPPV use

greater than 45 mmHg

what oxygen saturation finding suggests hypoventilation requiring NIPPV

nocturnal SpO₂ less than 88 percent for consecutive minutes

what inspiratory muscle strength indicates need for NIPPV

maximum inspiratory pressure less than 60 cmH₂O

what lung function value supports NIPPV use

forced vital capacity less than 50% predicted

what PaCO₂ level indicates severe stable COPD requiring NIPPV

greater than 55 mmHg

what combination of findings supports NIPPV in COPD with moderate hypercapnia

PaCO₂ between 50 and 54 mmHg with oxygen saturation less than 88 percent for 5 consecutive minutes

what hospitalization history supports NIPPV use in COPD

more than 2 hospitalizations in 12 months for hypercapnic respiratory failure

when is NIPPV indicated for nocturnal hypoventilation, OSA, or obesity

when polysomnography shows obstructive sleep apnea that is not responsive to CPAP

what are the exclusion criteria for NIPPV

respiratory arrest or need for immediate intubation, hemodynamic instability, inability to protect the airway, excessive secretions, agitation or confusion, facial deformities preventing mask fit, uncooperative or unmotivated patient, and brain injury with unstable respiratory drive

why is inability to protect the airway a contraindication for NIPPV

because impaired cough or swallowing increases risk of aspiration

what types of ventilators can be used for non-invasive ventilation

acute care ventilators, portable homecare ventilators, and pressure-targeted ventilators

what are features of acute care ventilators for NIPPV

they offer both invasive and non-invasive ventilation but require a software package for NIPPV

what are features of portable homecare ventilators

they are battery operated for chronic use and provide both invasive and non-invasive ventilation

what are pressure-targeted ventilators used for

nn-invasive ventilation only, typically in chronic care

what is a single limb circuit in NIPPV

a circuit where exhaled gas exits through a leak port rather than an exhalation valve

what is a double limb circuit in NIPPV

a circuit where exhaled gas exits through an exhalation valve without a continuous leak

what type of humidification is most commonly used in NIPPV

heated passover humidification

why is the patient interface important in NIPPV

it greatly affects how effectively positive pressure is delivered to the airway

what types of interfaces are available for NIPPV

nasal masks, oronasal masks, total face masks, helmets, nasal pillows, and mouthpieces with lip seals

what modes are used in NIPPV

CPAP, pressure support ventilation (IPAP/EPAP), and spontaneous/timed (S/T)

what is PSV (IPAP/EPAP) also commonly called

BiPAP or bilevel

when is PSV (IPAP/EPAP) most commonly used

in acute and chronic ventilatory failure

on what types of ventilators is PSV (IPAP/EPAP) available

acute care, pressure-targeted, and portable homecare ventilators

what is the control variable in PSV (IPAP/EPAP)

pressure

what is the breath sequence in PSV (IPAP/EPAP)

spontaneous

what phase variables are used in PSV (IPAP/EPAP)

patient-triggered and flow-cycled

what targeting scheme is used in PSV (IPAP/EPAP)

set point

how does a patient trigger a breath in PSV (IPAP/EPAP)

by reaching the sensitivity setting

what happens during inspiration in PSV (IPAP/EPAP)

the ventilator delivers a constant inspiratory pressure called IPAP

what causes the ventilator to switch to exhalation

when a percentage of peak flow is reached

what is IPAP

the inspiratory positive airway pressure, which represents the pressure support level

what does IPAP determine

the pressure difference and therefore ventilation

what is EPAP

the expiratory positive airway pressure, equivalent to PEEP or CPAP

what does EPAP determine

oxygenation

how is FiO₂ delivered in NIPPV

through connection to compressed gas with adjustable oxygen levels

what is an exception for FiO₂ delivery in NIPPV

pressure-targeted home ventilators require oxygen to be added into the circuit

what parameters determine ventilation in PSV (IPAP/EPAP)

IPAP and the pressure difference

what parameter determines oxygenation in PSV (IPAP/EPAP)

EPAP

what is spontaneous/timed (S/T) mode in NIPPV

a mode that includes spontaneous breaths with backup mandatory breaths

what is the control variable in S/T mode

pressure

what breath sequences occur in S/T mode

both spontaneous and mandatory breaths

what phase variables are used for spontaneous breaths in S/T mode

patient triggered and flow cycled

what phase variables are used for mandatory breaths in S/T mode

time triggered and time cycled

how are spontaneous breaths supported in S/T mode

they are supported to the IPAP level

what happens if the patient does not initiate a breath in S/T mode

the ventilator delivers a mandatory breath based on the set respiratory rate

how does the ventilator cycle during a mandatory breath in S/T mode

it delivers IPAP and then cycles to EPAP based on the set inspiratory time

what happens if the patient continues to trigger breaths regularly

the mode functions like pressure support ventilation

what condition is NIPPV indicated for in cardiogenic pulmonary edema

heart failure with pulmonary edema

what causes pulmonary edema in this condition

increased pulmonary capillary hydrostatic pressure due to elevated left atrial pressure

why does work of breathing increase in pulmonary edema

due to increased elastic recoil forces

why is alveolar ventilation decreased in pulmonary edema

because of increased elastic recoil

how does pulmonary edema affect oxygenation

it decreases ventilation-perfusion matching

how does NIPPV reduce work of breathing in pulmonary edema

IPAP increases pressure support, reducing the effort required to breathe

how does NIPPV improve alveolar ventilation

by assisting ventilation and reducing elastic load

how does EPAP help in pulmonary edema

it increases functional residual capacity and reduces elastic recoil

how does EPAP improve oxygenation

by improving ventilation distribution and ventilation-perfusion matching

how does NIPPV affect preload in cardiogenic pulmonary edema

it decreases preload

how does reducing preload benefit pulmonary edema

it lowers left atrial pressure and pulmonary capillary hydrostatic pressure

what is the result of decreased pulmonary capillary hydrostatic pressure

fluid is reabsorbed back into circulation