||Noninvasive positive-pressure ventilation
See also Respirators
It refers to the delivery of assisted ventilatory support without the
use of an endotracheal tube.
Techniques | Candidates
| Indications |
It inivolves the use of a mechanical ventilator connected by tubing to an
interface (full-face or nasal mask or mouthpiece with headstraps) that directs
airflow into the nose or the nose & mouth.
Continuous Positive Airway Pressure (CPAP)
It delivers a continuous positive pressure throughout the respiratory cycle
& is effective only if the patient is breathing spontaneously. It
cannot provide ventilation if the patient becomes apneic.
Bilevel Positive Airway Pressure (Bi-PAP)
It provides continuous PAP that allows independent control of inspiratory
& expiratory pressures. It can be administered in a spontaneous
setting (requiring the patient to initiate every ventilation), a timed setting
(preset ventilation intervals independent of patient effort), or both (allowing
the caregiver to determine a minimal respiratory rate).
It delivers a set volume for each breath. It is often poorly tolerated
because of the increased inspiratory pressure; It can be uncomfortable &
can cause air leaks around the mask.
It delivers a set pressure for each breath, is commonly administed with bilevel
PAP ventilators or with standard ventilators that use pressure support or
pressure control modes.
Ideal candidates are respiratory-insufficiency patients who are cooperative
and hemodynamically stable.
for NPPV - hypoxemia & hypercapnia
Acute Respiratory Failure due to COPD
It should be initiated before severe symptoms develop.
It decreases the need for endotracheal intubation & decreases mortality.
It causes fewer complications, & length of stay in ICU & hospital
Acute Respiratory Failure Not Related to COPD (Acute hypoxic respiratory
Asthma Exacerbation & Status Asthmaticus
- Need more controlled studies for these problems
Cardiogenic Pulmonary Edema
CPAP improves oxygenation & hypercapnia & decreases the need for
endotracheal intubation & the length of stay in the ICU.
Chronic Respiratory Insufficiency due to Neuromuscular disease, thoracic
deforminities, & idiopathic hypoventilation.
Severe Stable COPD
Evidence of acute cardiac ischemia or acute myocardial infarction
Unstable hemodynamic status
Impaired mental status
Need for airway protection to prevent aspiration
Inability to fit or wear the mask properly (facial deformity, claustrophobia,
Nasal congestion (may need in-line humidifiers, topical nasal corticosteroids,
Nasal bridge ulceration or Facial skin reddening (may need protective synthetic
covering as Duoderm)
Gastric distention (may need nasogastric tube)
From Mayo Clin Proc, August 1999, Vol 74:817 Jefferey T. Rabatin &
Peter C. Gay
Mayo Clin Proc, August 1999, Vol 74:817 Jefferey T. Rabatin & Peter
C. Gay (Review)
Chest 1999;115:863 Loube DI, Gay PC,
NEJM 1998 Aug.
13 ;339:429 Antonellli M, Conti G, Rocco M, etc.
NEJM 1997 Dec. 11:337:1746 Hillberg RE (Review)
Crit Care Med 1997;25:1685 Keenan SP