Continuous positive Airway Pressure (CPAP) Dr. A. K. Sarma OIL Hospital Duliajan

Objectives What is CPAP 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 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

(* In medium range of CPAP 4-7 cm H2O) Effects on Blood Gases 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 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

Clinical Indications

Indications Respiratory distress Apneic spells Post – extubation - 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 Increased pCO2 Recurrent apnea unresponsive to nasal CPAP Severe cardiovascular instability Upper airway abnormalities- cleft palate, choanal atresia, diaphragmatic hernia, TE fistula

Technique

Technique Nasal Nasopharyngeal Face mask with seal Headbox with seal Endotracheal

Technique: nasal prongs 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 ET-CPAP Nasal Low 3-4 4-5 Medium 5-7 6-8 High 8-10 9-11 (Add 1 cm extra for nasal CPAP)

CPAP ranges (cm H2O) CPAP of < 3 cm H2O never given! 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 Pressure : 5-6 cm H2O FiO2 : 0.4 – 0.5

Further steps First raise pressure till 8 cm H2O in steps of one cm 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) F1O2 8 0.7 8 0.6 8 0.5 8 0.4 7 0.4 6 0.4 5 0.4 4 0.4 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

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 Containing retractions, grunt Recurrent apnea PaO2<50 torr at highest setting PaCO2>55 torr Baby not tolerating CPAP despite best efforts

Nursing care Humidity, warm the gases (34-370 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 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 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.

A relatively safe life-saving modality with a great potential Conclusion A relatively safe life-saving modality with a great potential

Kinder Gentler cost effective respiratory support CPAP!

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