Transcript Continuous positive Airway Pressure (APAP)

Continuous positive
Airway Pressure (CPAP)
Dr. A. K. Sarma
OIL Hospital
Duliajan
Objectives
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What is CPAP
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How does it work
Effects
 When should we use it
Evidence, indications, contraindications
 How to use
Equipment, technique, monitoring, tips and weaning
What is CPAP
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Continuous positive pressure during
inspiratory and expiratory phase
- CPAP in an infant breathing with his own
effort
- Positive End Expiratory Pressure (PEEP) in
an infant on ventilation
Physiological mechanisms
Recruitment of atelectatic alveoli
 Increase in FRC
 Improved compliance
 Decrease in airway resistance
 Conservation of surfactant
 Stabilization of chest cage
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Effects on Blood Gases
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Oxygen improves
Due to better FRC
 Carbon dioxide declines*
Due to increased surface for gas exchange
(* In medium range of CPAP 4-7 cm H2O)
Adverse effects
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Pulmonary
- Overdistension, diminished compliance
- Air leaks (with ET-CPAP)
Cardiovascular
- Increase CVP
- Decrease venous return, decreased cardiac
output resulting in hypotension
- Increase pulmonary vascular resistance
- Metabolic acidosis
Adverse effects
CNS
Increase intracranial pressure
Decrease cerebral perfusion
 GIT
Bowel distension by swallowed air
Decreased blood flow
 Kidneys
Decreased blood flow
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Clinical Indications
Indications
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Respiratory distress
- RDS, HMD
- TTNB, delayed adaptation
- MAS, pneumonia
 Apneic spells
- Apnea of prematurity
 Post – extubation
 Others
- Tracheomalacia
Indications
ET CPAP before extubation
Direct extubation is associated with increased
chance of successful extubation compared to
ET-CPAP
Contraindications
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Increased pCO2
Recurrent apnea unresponsive to nasal CPAP
Severe cardiovascular instability
Upper airway abnormalities- cleft palate,
choanal atresia, diaphragmatic hernia, TE
fistula
Technique
Technique
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Nasal
Nasopharyngeal
Face mask with seal
Headbox with seal
Endotracheal
Technique: nasal prongs
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Most effective
Baby can pop off
Less invasive
Lesser work of breathing
But difficult to keep in place
Technique: nasal prongs
Clinical use
CPAP ranges (cm H2O)
Physiological 3 cm H2O
 Low
 Medium
 High
(Add 1 cm extra for nasal CPAP)
ET-CPAP
3-4
5-7
8-10
Nasal
4-5
6-8
9-11
CPAP ranges (cm H2O)
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CPAP of < 3 cm H2O never given!
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CPAP of 4-7 cm H2O is good range.
Advantage many, disadvantage few
 CPAP of over 8 cm H2O is a bad range
Advantage some, disadvantage galore!
Initiation
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Pressure :
5-6 cm H2O
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FiO2
0.4 – 0.5
:
Further steps
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First raise pressure till 8 cm H2O in steps of
one cm
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Then raise FiO2 to 0.8 in steps of 0.05
Further steps
Adjustment of oxygen saturation & PaO2
•
•
CPAP (cm H2O)
F1O2
5
0.5
6
0.5
7
0.5
8
0.5
8
0.6
8
0.7
8
0.8
First raise CPAP till 8 cm H2O in steps of 1 cm
Then raise FiO2 to in steps of 0.05
Weaning
Reach CPAP to 8 cm H2O
Reduce FiO2 to 0.4 in steps of .05
Reduce pressure to 4 cm in steps of 1 cm H2O
Stop CPAP and put in oxygen hood
Weaning
CPAP (cm H2O)
8
8
8
8
7
6
5
4
• Reduce F1O2 to 0.4 in steps of 0.05
• Then reduce CPAP to 4 cm in steps of 1 cm
• Then stop CPAP, put baby in oxygen hood
F1O2
0.7
0.6
0.5
0.4
0.4
0.4
0.4
0.4
Monitoring during CPAP
Clinical
• RR, grunt, retractions, apnea, cyanosis
• HR, pulse, perfusion and BP
• Temperature, cold stress
• Abdominal girth, Urine output
• CPAP device: fixation, blockage, local damage
Pulse oximetry: 90-93%
ABG
Adequacy of CPAP
Satisfactory cardiorespiratory status
• Comfortable baby
• No retraction, no grunt
• Normal capillary refill, BP
• Normal saturations: 90-93%
(set alarms at 88 and 95%)
• Normal ABG
(PaO2 60-80, PaCO2 40-50, pH 7.35-7.45, BE±2)
Failure CPAP
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Containing retractions, grunt
Recurrent apnea
PaO2<50 torr at highest setting
PaCO2>55 torr
Baby not tolerating CPAP despite best
efforts
Nursing care
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0
Humidity, warm the gases (34-37 C)
Keep gas flow at 5-8 lit/min
Ensure patency of prongs
Suction mouth and nose SOS
Installing saline drops in nares helps
Nursing care
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Put orogastric tube to decompress the
stomach
Change prongs/circuit every third day
Stabilize the head of baby
Ensure asepsis
Nursing care
Babies on CPAP can
be fed by OG tube
but with care!!!
Benefits-Bubble CPAP
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The oscillatory pressure waveform gets
transmitted into the lungs from the airway
and may contribute to gas exchange,
decreasing the infants work of breathing
Prerequisites for setting up a CPAP unit
Mandatory (M)/desirable ( D)
Source of air, oxygen (central/jumbo cylinders connected by a manifold) (M)
CPAP machine with
Blender (for control of Fio2) ( M ),provision to measure Fio2 ( D )
Humidification & warmidification of gases ( M )
Pressure measuring device /release valves for safety ( D )
ABG machine ( D ), pulse oximeter ( M )
Portabule X-ray machine ( M )
Facilities to drain a pneumothorax ( M )
Provision to ventilate if CPAPfails, in the unit ( D),to transport safely (M)
Surfactant therapy ( D )
Trained Pediatrican & Nurses (M)
Support services ( D )
Our Observation
The efficiency of applying continuous positive airway pressure (CPAP) by
nasal route was retrospectively analyzed in 15 newborns with respiratory distress
syndrome (9 uncomplicated hyaline membrane disease, 1 hyaline membrane disease
with cardiac complication, 3 meconium aspiration syndrom, 2 transient techypnoea
of newborn )
Who underwent nasal CPAP treatment in oil India hospital Duliajan, Assam
from 01-12-2006 to 31-11-2007. 7 out of 9 cases of uncomplicated HMD were
successfully treated with CPAP. They showed a significant improvement. The
remaining 6 newborn in this group (6/15), 3 had to be intubated and mechanically
ventilated owing to persistent high Fio2 (2), technical difficulties (1).
2 of 3 meconium aspiration syndrome baby needed mechanical ventilation.
Both TTN cases were doing well in nasal CPAP. Two of these 15 cases died, one
of cerebral haemorrhage & another in sepsis.
The nasal CPAP as described is a simple inexpensive and effective method of
applying CPTPP in newborn with uncomplicated HMD, except radiological stage
IV. In TTN it is an excellent modality but in RDS due to meconium aspiration
syndrome the result of nasal CPAP treatment were not convincing.
Recent clinical concept in CPAP
Permissive hypercarbia
This is a strategy of Babies & Children’s Hospital. Columbia
University, New York. The strategy involves use of bubble CPAP in
early course of respiratory distress in both preterm & term babies,
the clinicians accept hypercapnia – PCO2 levels up to 60 or higher
and PaO2 levels low 50 or even lower and pH levels as low as 7.2
They have shown lesser need for mechanical ventilation (75
vs 29%) and surfactant therapy (45 vs 10%) when compare to
VLBW babies managed at Boston. The mortality rate on both
strategies were similar, but the incidence of CLD far lower in the
bubble CPAP – Columbia NICU (4% vs 22% at Boston) Long term
pulmonary and neurological outcomes have not been studied /
compared.
Conclusion
A relatively safe life-saving modality with a
great potential
Kinder Gentler cost effective
respiratory support
CPAP!
Thank You