Continuous spontaneous ventilation

Continuous spontaneous ventilation

Uses	Gives assisting pressure and flow during inhalation.
Trigger	Flow, Volume or Pressure
Limit	Pressure
Inspiratory Cycle	Flow
Servo	no
Settings	CPAP; IPAP, EPAP; or PEEP+PS

Continuous spontaneous ventilation is any mode of mechanical ventilation where every breath is spontaneous (i.e., patient triggered and patient cycled).

Pressure support

Pressure Support (PS) is a spontaneous mode of ventilation also named Pressure Support Ventilation (PSV). The patient initiates the breath and the ventilator delivers support with the preset pressure value. With support from the ventilator, the patient also regulates the respiratory rate and the tidal volume^[1].

In Pressure Support, the set inspiratory pressure support level is kept constant and there is a decelerating flow. The patient triggers all breaths. If there is a change in the mechanical properties of the lung/thorax and patient effort, the delivered tidal volume will be affected. The user must then regulate the pressure support level to obtain desired ventilation^[2].

Continuous positive airway pressure ventilation

CPPV — Continuous positive airway pressure ventilation is fundamentally the use of continuous positive airway pressure (C_PAP) to maintain a continuous level of positive airway pressure. It is functionally similar to P_EEP, except that PEEP is an applied pressure against exhalation and C_PAP is a pressure applied by a constant flow. The ventilator does not cycle during C_PAP, no additional pressure above the level of C_PAP is provided, and patients must initiate all of their breaths. Nasal C_PAP is frequently used in neonates though its use is controversial. Studies have shown nasal C_PAP to reduce ventilator time but an increased occurrence of pneumothorax was also prevalent.^[3]

As a treatment or therapy, CPAP uses mild air pressure to keep an airway open. CPAP typically is used for people who have breathing problems, such as sleep apnea.

CPAP also may be used to treat preterm infants whose lungs have not yet fully developed. For example, physicians may use CPAP to treat infants who have respiratory distress syndrome or bronchopulmonary dysplasia. In some preterm infants whose lungs haven't fully developed, CPAP improves survival and decreases the need for steroid treatment for their lungs.

CPAP at home utilizes machines specifically designed to deliver a constant flow or pressure. Some CPAP machines have other features as well, such as heated humidifiers. CPAP is the most effective treatment for obstructive sleep apnea, in which the mild pressure from CPAP prevents the airway from collapsing or becoming blocked.

Settings and measurements

• C_pap — This is the pressure applied without pause or end to the airway. Generally utilizing flow to generate the pressure.
• PEEP — PEEP is sometimes also called CPAP however the pressure generated in PEEP is by a backpressure valve forcing increased pressure on exhalation, ultimately creating a sustained (continuous) pressure.
• FiO₂ — The fractional O2 percentage that is being added to the delivered air.

Bilevel positive airway pressure

BPAP — Bilevel positive airway pressure (BPAP) is a mode used during noninvasive positive pressure ventilation (NPPV). It delivers a preset inspiratory positive airway pressure (IPAP) and expiratory positive airway pressure (EPAP). B_PAP can be described as a Continuous Positive Airway Pressure system with a time-cycled change of the applied CPAP level.^[4] C_PAP, B_PAP and other non-invasive ventilation modes have been shown to be effective management tools for chronic obstructive pulmonary disease and acute respiratory failure.^[5]

Discouraged terminology

Often B_PAP is incorrectly referred to as "BiPAP". BiPAP® is the name of a portable ventilator manufactured by Respironics Corporation; it is just one of many ventilators that can deliver B_PAP.

Settings and measurements

• I_pap — This is the pressure applied during patient triggered breaths.
• E_pap — This is the pressure applied in between patient triggered breaths. Could also be considered a continuous positive pressure.
• FiO₂ — The fractional O2 percentage that is being added to the delivered air.
• V_f — On many machines a respiratory rate it set as a gurantee for intermittent bursts of I_pap.

See also

• Modes of mechanical ventilation
• Volume controlled continuous mandatory ventilation
• Volume controlled intermittent mandatory ventilation
• Pressure controlled continuous mandatory ventilation
• Pressure controlled intermittent mandatory ventilation

References

1. ^ MAQUET, "Modes of ventilation in SERVO-i, invasive and non-invasive", 2008 MAQUET Critical Care AB, Order No 66 14 692
2. ^ MAQUET, "Modes of ventilation in SERVO-s, invasive and non-invasive", 2009 MAQUET Critical Care AB, Order No 66 61 131
3. ^ Colin J. Morley, Peter G. Davis, Lex W. Doyle, Luc P. Brion, Jean-Michel Hascoet & John B. Carlin (February 2008). "Nasal CPAP or intubation at birth for very preterm infants". The New England journal of medicine 358 (7): 700–708. doi:10.1056/NEJMoa072788. PMID 18272893. 
4. ^ C. Hormann, M. Baum, C. Putensen, N. J. Mutz & H. Benzer (January 1994). "Biphasic positive airway pressure (BIPAP)--a new mode of ventilatory support". European journal of anaesthesiology 11 (1): 37–42. PMID 8143712. 
5. ^ M. A. Levitt (November 2001). "A prospective, randomized trial of BiPAP in severe acute congestive heart failure". The Journal of emergency medicine 21 (4): 363–369. PMID 11728761.