CSD 726: Assignment 2
Piper Doering
Spring, 2013
Compare and contrast the following types/modes of ventilation: AC, CPAP, PSV, & BiPAP.
Assist-controlled (AC), continuous positive airway pressure (CPAP), pressure support
ventilation (PSV), and inspiratory/expiratory positive airway pressure (BiPAP) are all noninvasive modes of ventilation that are available for patients in need of respiratory support. All
four are unique, yet similarities are found amongst each type. Following is a description of each
type, highlighting the similarities to other ventilation systems as the opportunities arise.
AC ventilation can either be triggered by the patient or pressure is automatically applied per the
set amount of the ventilator (Silbergleit & Basha, 2006). When a patient triggers a breath, this
means that he/she is making an effort to inhale. This registers with the ventilator and the set
amount of tidal volume is applied. If a patient does not put in the effort to initiate a breath, AC
ventilation delivers a control breath. These control breaths occur at a set amount of breaths per
minute, which has been determined by a physician; this is called minute volume (Silbergleit &
Basha, 2006). Either way, the same amount of pressure is given for both patient-initiated and
non-initiated breaths. While pressure is delivered during inspiration, exhalation is essentially
passive (Silbergleit & Basha, 2006). During expiration, expiratory muscles and recoil forces are
at work.
In contrast to AC ventilation, CPAP ventilation applies pressure to the lungs during inspiration
and expiration via an endotracheal tube or a mask (Silbergleit & Basha, 2006). Thus, there is a
constant, positive pressure being delivered to the spontaneously breathing patient. When pressure
is applied during inspiration, the demand placed on the muscles of inspiration decreases and the
overall end-expiratory lung volume increases. This pressure is commonly between 5 and 10 cm
H20, which has been determined by a physician (Silbergleit & Basha, 2006). CPAP ventilation is
used for a wide range of patients, from those who are weaning from breath support to those who
have impending respiratory failure (Silbergleit & Basha, 2006).
PSV is also for a spontaneously breathing patient; however, pressure is only applied during
inspiration (Silbergleit & Basha, 2006). With pressure being applied to the inspiratory cycle, this
eases the process of breathing in. This is especially useful for patients with an increased
inspiratory resistance, such as a tumor (Silbergleit & Basha, 2006). Inspiratory pressure is
applied through an endotracheal tube or a mask, similar to CPAP ventilation. Once again, the
pressure is physician-determined. During expiration, expiratory muscles and recoil forces are at
work as in AC ventilation, allowing expiration to be a passive process. PSV can be used with a
wide range of patients, similar to CPAP ventilation (Silbergleit & Basha, 2006).
BiPAP applies a constant pressure during inspiration and expiration, just like CPAP ventilation.
Thus, this type of ventilation also supports the entire respiratory cycle, raising end-expiratory
volume. However, the amount of pressure applied during the inspiratory and expiratory cycles
varies to accommodate patients with different disease processes (Silbergleit & Basha, 2006).
Yet, BiPAP is still similar to CPAP and PSV in that patients must be spontaneously breathing,
and pressure is applied through a nasal or face mask (Silbergleit & Basha, 2006). BiPAP is the
best fit for “patients who require either partial ventilator support or those who have impending
respiratory failure” (Silbergleit & Basha, 2006, p. 263). BiPAP ventilators are not used to wean
patients off of support, like CPAP and PSV are useful for.
Summarize the pre-placement issues one needs to consider when determining whether one is a
candidate for speaking valve placement.
Medically-based speech language pathologists (SLPs) work closely with patients learning to
communicate with tracheostomy tubes. When a patient is a candidate for voicing, an SLP must
take specific steps in sorting through pre-placement issues. After medical clearance is received,
consideration must be given to medical history, physical examinations, and a trial run.
The first step is to assess whether or not the patient is even a candidate for voicing. This initial
evaluation involves a review of the patient’s medical history. By looking at medical history, an
SLP can anticipate challenges that may arise to speaking valve communication from a linguistic,
cognitive, speech, and voice standpoint (Sibergleit & Basha, 2006). A cognitive screener should
be given to confirm past reports and to receive status on most recent condition.
A patient’s most recent history must also be considered, including why and when the
tracheostomy tube was placed, the type of tube, and overall health. The tube must be small
enough to allow for adequate airflow and the patient must be able to tolerate cuff deflation (Hull,
Dumas, Crowley, & Kharasch, 2005). In addition, a foam cuff does not allow for a speaking
valve. From an overall health standpoint, there are some contraindications that should be red
flags to SLPs. Specifically, a client must not have a serious illness, a laryngectomy, nor be in an
unconscious state (Woodnorth, 2004).
A physical examination must take place in the laryngeal area. An SLP should take note of severe
tracheal or laryngeal obstructions, vocal fold paralysis, and the presence of unmanageable
secretions (Woodnorth, 2004). If present, these are contraindications of a speaking valve. An
SLP should also be on the lookout for vocal fold paralysis and granulation of tissue. However, if
these indications exist, this does not prevent the use of a speaking valve. Rather, these
indications alert the SLP to problems that may occur during voicing (Sibergleit & Basha, 2006).
Another physical examination must examine the patient’s oral-motor status. Here, an SLP
determines the overall structure and health of a patient’s intraoral motor movements and
functioning. Alternative modes of communication may be necessary if the patient has severely
limited movements to his/her tongue, lips, checks, and mouth (Sibergleit & Basha, 2006). A
speaking valve would not provide full benefit to the patient if these oral-motor weaknesses are
present.
An initial trail of a speaking valve is also required. During this trial run, heart rate, respiratory
rate, and blood oxygen levels are all considered (Hull et al, 2005). An SLP is expected to take a
closer look at the client’s ability to phonate, his/her intelligibility, and voice quality (Hull et al,
2005). In general, an SLP must be aware of the patient’s facial expressions and be watching the
patient’s vitals. The overall focus of these pre-placement issues should be summed up with an
awareness placed on the benefits a patient will receive from speaking valve use.
References
Hull, E.M., Dumas, H.M., Crowley, R.A., & Kharasch, V.S. (2005). Tracheostomy speaking
valves for children: Tolerance and clinical benefits. Pediatric Rehabilitation, 8(3), 214219.
Silbergleit, A.K. & Basha, M.A. (2007). Speech-language pathology in the intensive care unit. In
A.F. Johnson & B.H. Jacobson (Eds.), Medical speech-language pathology: A
practitioner’s guide (2nd ed.)(pp.260-283). New York, NY: Thieme.
Woodnorth, G.H. (2004). Assessing and managing medically fragile children: Tracheostomy and
ventilator support. Language, Speech, and Hearing Services in Schools, 35, 363-372.