TRIPASS XR تري باس

 

231

Hany Aly

M.A. Mohamed

Bubble Nasal Continuous

Positive Airway Pressure

35

A. Definition

Continuous positive airway pressure (CPAP) is a noninvasive, continuous flow respiratory system that maintains positive pressure in the infant’s airway during spontaneous

breathing. CPAP was developed by George A. Gregory in

the late 1960s (1). Positive pressure was originally applied

by placing the neonate’s head into a semiairtight “box” (the

Gregory box) and, subsequently, by a fitted face mask covering the mouth and nose (2). A major problem with both

these methods of application was the fact that it was difficult

to feed the baby without discontinuing the CPAP, thus the

evolution to the current method of applying CPAP through

bilateral nasal prongs (3). “Bubble CPAP” (b-CPAP) is a

modern resurgence of the original method of supplying

CPAP, wherein pressure is generated in the breathing circuit by immersing the distal end of the expiratory limb of

the breathing circuit under a water seal (4–6) (Fig. 35.1).

Bubble CPAP allows provision of CPAP without use of

a ventilator, and it is currently primarily used for early treatment of low-birthweight premature infants with or at risk for

respiratory distress syndrome and/or with frequent apnea/

bradycardia (7). In addition to cost considerations, there is

early evidence that b-CPAP may be more effective in small

premature babies than ventilator-derived CPAP (8).

CPAP has the Following Physiologic Actions

1. Prevents alveolar collapse and increases functional

residual capacity

2. Splints the airway and diaphragm

3. Stimulates the act of breathing and decreases apnea

4. Conserves surfactant via decreased inflammatory

responses (9)

5. Stimulates lung growth when applied for extended

duration (10)

B. Indications

1. Premature infants with/at high risk for respiratory distress syndrome

2. Premature infants with frequent apnea and bradycardia

of prematurity

3. Infants with transient tachypnea of the newborn

4. Infants who have weaned from mechanical ventilation

5. Infants with paralysis of the diaphragm or tracheomalacia

When to Start b-CPAP?

a. Premature infants with a birthweight <1,200 g can

be supported with b-CPAP starting in the delivery

room, before any alveolar collapse occurs

b. Infants ≥1,200 g may benefit from b-CPAP in the

following conditions

(1) Respiratory rate >60 breaths/min

(2) Mild to moderate grunting

(3) Mild to moderate respiratory retraction

(4) Preductal oxygen saturation <93%

(5) Frequent apneas

C. Contraindications

1. Choanal atresia

2. Congenital diaphragmatic hernia

3. Conditions where b-CPAP is likely to fail in the delivery room such as

a. Extremely low gestational age infants (≤24 weeks)

b. Floppy infants with complete apnea due to maternal anesthesia

4. Relative contraindication: Infants with significant apnea

of prematurity may require the introduction of nasal

intermittent positive pressure ventilation via a variable

flow device (11).

D. Equipment

B-CPAP System Consists of Two Components

1. A breathing circuit of light-weight corrugated tubing

that has two limbs

a. Inspiratory limb to provide a continuous flow of

heated and humidified gas

b. Expiratory limb with its terminal end immersed

under water seal to create positive pressure

2. A device to safely connect the circuit to patient’s nares

that includes (Fig. 35.2)