• It is Continuous Positive Airway Pressure applied to
the airways of a spontaneously breathing patient
throughout the respiratory cycle.
• By which alveoli are kept open which increase the
functional residual capacity(FRC) of the lungs
resulting in better gas exchange.
• Harrison 1968: described grunting in neonates as
naturally producing end expiratory pressure.
• Gregory et al, 1971: introduced the clinical use of
distending pressure in neonates.(via endotrachial tube
or a head box)
• Kattwinkel reported successful use of nasal prongs in
neonates with RDS. ‘-1973
• Reports of significant lower incidence of chronic lung
disease from columbia university that used more CPAP
as compared to north american centre have led to
resurgence of interest in CPAP over the last 15 years.
A Device for Administration of Continuous Positive Airway Pressure by the Nasal Route
John Kattwinkel, David Fleming, Chul C. Cha, Avroy A. Fanaroff, Marshall H. Klaus
• Surface tension is the elastic tendency of
a fluid surface which makes it acquire the
least surface area possible.
r = 2
T = 3
P = (2 x 3) / 2
P = 3
r = 1
T = 3
P = (2 x 3) / 1
P = 6
Law of LaPlace : P = 2T/r
P : pressure T : surface tension r : radius
• Thus smaller (diameter) alveoli will have a
tendency to empty into larger (diameter) alveoli
connected to each other.
• If the surface tension is reduced by giving
exogenous surfactant, the inward pressure which
leads to collapse can be reduced.
• By giving CPAP, one neutralizes the inward
• The net effect of both is more than additive. This
principle is applied in clinical practice for INSURE
(Intubate give Surfactant and Extubate to CPAP).
• Closing volume is the volume of lung inflated
when small airways in the dependent parts of
the lung begin to collapse during expiration.
Physiological Benefits of CPAP:
• Results in improved oxygenation, wash out of
CO2, and better blood pH.
• Stimulates ’J’ receptors by stretching the
lung/pleura and providing positive feedback to
respiratory centre by Hering Bruer reflex.
• Results in better Type II-pneumocyte function
and even recycling of surfactant thus
contributing to early recovery from HMD.
• Results in better ventilation-perfusion match,
improved minute ventilation and decreased
work of breathing.
• Splints the upper airways thus preventing
Diseases with low FRC
Diseases with airway instability
Apnea of prematurity
Weaning from IMV
MAS, aspiration, pneumonia
• Severe Cardiovascular instabality ( SHOCK)
• Progressive respiratory failure with PaCO2 >60
mm hg and inability to maintain
• Certain congenital malformations of the
airway like choanal atresia, cleft palate,
tracheo osophageal fistula, CDH.
An ideal CPAP delivery system consists of:
• A continuous supply of warm, humidified,
blended gases at a flow rate of 2-3 times the
infant minute ventilation.
• A device to connect CPAP circuit to infants
airway. (patient interface)
• Means of creating a positive pressure in CPAP
Bubble CPAP- principle
NP ET tubeUnder
Patient interfaces for cpap
Short bi-nasal prongs Argyle prongs
Delivery system advantages disadvantages remarks
Nasal prongs(single or
on, IFD prongs.
Simple device. Lower
leak acts like a pop-off
Relatively difficult to
fix. Risk of trauma to
nassal septum. Leak
through mouth means
pressure is variable.
Studies have shown
that they are more
More easily blocked
by secretions: likely to
economical, they are
inferior to short
Nasal canualae. Easy application Unreliable pressure.
May need high flows
to genarate pressure.
FiO2 delivered may be
Mainly tried in apnea
Paucity of data in
other condition. Still a
Nasal mask minimal nasal
Difficulty in obtaining
a tight seal
New generation mask
are to be studied.
1. Position the baby in
supine position with
the head elevated
about 30 degrees
2. Place a small roll
under the baby’s neck
3. Put a pre-made hat or
stockinet on the
baby’s head to hold
the CPAP tubings
4. Choose FiO2 to
keep PaO2 at 50-80
O2 saturation at
85% – 95%
5 Adjust a flow rate 5-10 Lpm
a) provide adequate flow to
prevent rebreathings CO2
b) compensate leakage from
tubing connectors and
around CPAP prongs
c) generate desired CPAP
pressure (usually 5
6. Keep inspired gas
temperature at 36-40O C
(0 ~ –3)
7. Insert the lightweight
heating wire inside) in a
bottle of 0.25% acetic
acid solution or sterile
water filled up to a
height of 7 cm. The tube
is immersed to a depth
of 5 cm to create 5
cmH2O CPAP as long as
air bubbling out of
Lubricate the nasal
CPAP prongs with
sterile water or
saline. Place the
prongs curved side
down and direct into
on both sides of
the hat with
pins and rubber
band or velcro
1. Observe baby’s vital signs, oxygenation and activity
2. Systematically check CPAP systems, inspired gas
temperature, air bubbling out of acetic acid
solution. Empty condensed water in the circuit
3. Check CPAP prongs position and keep CPAP
cannulae off the septum at all times.
Maintaining Optimal Airway
• Maintain adequate
humidification of the circuit
to prevent drying of
• Adjust settings to maintain
gas humidification at or
close to 100%.
• Set the humidifier
temperature to 36.8- 37.3c
SETTING PRESSURE, FLOW & FiO2
1. Pressure- regulated by depth of immersion of
expiratory limb(water level being constant).Start
with 5 cm water in case of RDS or pneumonia and
4 cm water for apnea management.(range- 4-8)
2. Flow- it should be minimal to produce bubbling
in the bubble chamber(2-5 L/min is sufficient)
3. FiO2- start with a FiO2 of 40 to 50% and after
adjusting the pressure,titrate FiO2 to maintain
SpO2 between 87% to 93%.
Adequacy of CPAP
• Comfortable baby
• No retraction, no grunt
• Normal capillary refill, BP
• Normal saturations: 87-93%
• Normal ABG
(PaO2 60-80, PaCO2 40-60, pH 7.35-7.45, BE±2)
Failure of CPAP
• Continuing retractions, grunt.
• Recurrent apneas
• PaO2 < 50mm Hg at highest setting.
• PaCO2 > 60 mm Hg
• Baby not tolerating CPAP
• FiO2 required is greater than
• Inability to maintain SPO2>85%
WEANING FROM CPAP
• It is considered when clinical condition for which
CPAP was indicated is passive.
• CPAP for apnea may be removed after 24 -48 hrs
of apnea free interval.
• If the baby is stable on CPAP,first wean off the
oxygen in steps of 5% and then wean PEEP to
minimum of 4cm in step of 1cm/change.
• When baby is in FiO2<30%, PEEP 4cm, with
normal saturation and minimal retraction CPAP
can be removed.
Complications associated with bubble
• Pneumothorax / PIE - more in the acute phase
- not a contraindication for continuing CPAP
• Nasal obstruction - Remove secretions and
check for proper positioning of the prongs
• Nasal septal erosion or necrosis - Keep prongs
away from the septum
• Gastric distension
Intermittent or continuous aspiration of the
• Feeding intolerance
Prevention of Gastric distension:
• NCPAP is not a contraindication to enteric feeding.
• Infants may experience mild abdominal
distention during NCPAP delivery from
• Assess the infant’s abdomen regularly
• Pass an oro-gastric tube to aspirate excess air
before feeds q 2-4 hr
• An 8 Fr oro-gastric tube may be left indwelling to
allow for continuous air removal
• CPAP used in RDS, apnea, weaning.
• Pressure generator
– Bubble CPAP
• Circuit of choice
– Heated humidifier
• Nasal device of choice
– NP CPAP > cannula
• CPAP range 4-8
• Ashok Deorari et al .Workbook on CPAP –Science
Evidence and practice,2014.
• Eduardo Bancalari.Principles of respiratory
Monitoring and theraphy.Avery s diseses of
• Aparna ,Non Invasive ventilation in Newborn.
• Samir Gupta .CPAP .To bubble or not to
Bubble.Non invasive ventilation.Clinics in