Neonatal Medicine: CPAP and Ventilation in Neonatal Respiratory Distress
You are reviewing Nathan, a 12 hour old neonate with respiratory distress.He is 37 weeks gestation and was born by caesarean section following failure to progress.The oxygen saturation is 94% in 50% FiO2, the respiratory rate is 80.
There is moderate intercostal recession and an occasional grunt. Your hospital participated in the “bubbles for babies” trial and you have just started to use CPAP in your unit now the trial is finished. Your registrar suggests using CPAP on this neonate, but the nursing staff have called you to arrange transfer.
Would you use CPAP or ventilate and transfer this neonate?
Please give reasons for your choice with reference to the current literature.
In your answer you should also consider the following main points:
• the benefits of CPAP over ventilation, particularly with reference to your current practice environment
• the potential complications of CPAP
• reasons why ventilation may be required even though CPAP is in situ.
The baby Nathan is suffering from Neonatal respiratory distress syndrome, which is a condition most often seen in newborn babies and is characterized by a difficulty in breathing. The condition more frequently develops in prematurely born babies as their lungs are not fully developed. The lubricant that lines the inner membranes of the lungs (known as ‘surfactant’) is deficient, thus causing difficulty in inflating the lungs and resulting in the air sacs collapsing.
Surfactant helps to lower the surface tension of water that is present on the alveoli, thus helping to prevent the lung sacs from collapsing. Usually, the condition develops in infants born before the 38 week. The baby is cyanosed and has difficulty in breathing. The accessory muscles of respiration are active and a frequent grunting sound is heard. The other symptoms that may be observed include nasal flaring, shallow breathing, swollen legs, unusual movement of the chest wall, etc.
The infant may be hypoxic and the CO2 levels in the blood rise. The symptoms usually develop at birth, or a little while after birth. The symptoms tend to worsen and may progress to respiratory failure and death. As the prematurity increases, so does the chance of developing this condition. This is because surfactant is produced only during the later stages of gestation in the infant. The diagnosis of RDS in babies is made based on the history, presence of certain risk factors, Chest X-ray, Blood tests, CSF studies, lung tests, blood gas analysis, etc (Greene, 2007 & Merck, 2005).
When a neonatal is born, certain signs are observed which include:-
a heart rate between 110 to 150 beats per minute
a respiratory rate between 40 to 70 breathes per minute
absence of cyanosis, nasal flaring, grunting sounds, forceful use of accessory muscles during respiration, etc
Oxygen saturation which is about 95 %
the P ao2 is higher than 50 %
the FiO2 is about 40 to 50 % (CCM, 2007, NGC, 2008, & Millar et al, 2004)
Previously, for the treatment of RDS, ventilatory support was utilized. This may be utilized if the blood carbon dioxide levels are high, the blood oxygen levels are low, and if acidosis sets in. To some extent ventilation helps to reduce the infant mortality rate arising from RDS, but the morbidity to develop Bronchopulmonary dysplasia (a condition characterized by oedema of the air sacs and of the connective tissues due to persistent inflammation) is high as the young neonatal lungs are damaged from ventilation.
One of the treatments that have been developed in order to overcome the limitations of ventilation is Continuous Positive Airway Pressure (CPAP). This is an advanced form of therapy in which the upper and the lower airways receive a continuous distending pressure through the infant’s pharynx and/or nose throughout the respiratory cycle. An endotracheal tube can also be utilized. The device is connected to a gas source that provides humidified warm air continuously (NGC, 2008, Millar et al, 2004, Tidy, 2007).
CPAP has several benefits including:-
helps to maintain a normal breathing pattern
helps to arrive at normal functional residual capacity
helps to lower any airway resistance in the upper respiratory tract
helps to prevent development of apnea
prevents the airways and the air sacs from collapsing
helps stimulate release of surfactant
helps to increase the lung volume and lung function
After expiration, CPAP helps to keep the air sacs open
The chances of developing lung trauma such as barotrauma and atelectotrauma are lesser (CCM, 2007, Sehgal, 2003, NGC, 2008, Millar et al, 2004).
CPAP is required in several situations that arise from RDS including:-
When it is difficult to maintain the Pa02 above 50 %.
When the respiratory rate is above 70 breathes per minute
Excessive use of the accessory muscles of respiration
The oxygen saturation falls to between 90 to 95 %
The presence of apnea
It can be utilized along with administration of surfactant that develops out of the need to treat RDS (CCM, 2007, Sehgal, 2003, NGC, 2008, Millar et al, 2004).
As the patient is not suffering from a severe form of RDS and the oxygen saturation levels have not dropped to a serious extent, ventilatory support is not required, and the patient can be treated with CPAP. Besides, the findings do not suggest that the patient is suffering from a cardiovascular complication, an upper respiratory tract abnormality or intractable apneic episodes. Along with CPAP, several other measures are required such as using larger nasal prongs, ensuring that the baby is in a prone position and keeping a towel below the neck. This helps to ensure that the certain areas are aerated better (CCM, 2007, Sehgal, 2003, NGC, 2008, Millar et al, 2004).
CPAP has several complications including:-
mucous from the upper respiratory tract may block the nasopharyngeal tube that delivers CPAP
Sometimes blockages may result in the pressure rising to higher levels in the tube
If the peak pressure is very high, then gastric complications can develop
The nasopharyngeal tube has to be placed in exact position. Any deviation from the position can result in fluctuation of the air pressure
The nasal devices may be swallowed or aspirated resulting in severe complications
Sometimes harnesses may be utilized to place the head and the neck in position. This may cause serious dermatological and musculoskeletal complications in the infant
Air leakage problems in the lungs
Decrease in the cardiac output
Higher working of breathing
pneumothoraces and air embolism can also develop
Cardiac monitoring needs to be performed more closely in the case of CPAP compared to ventilation
often air leaks from the nose and the mouth
it may be very difficult to control the air pressure in the lower airways
If CPAP is applied to an infant with normal lungs, several problems can develop
Several respiratory complications such as pneumothorax, pneumomediastinum, and pneumopericardium can develop (CCM, 2007, Sehgal, 2003, NGC, 2008, Millar et al, 2004, Halamek et al, 2006)
- California College of Midwives (20080, Guidelines for Assessing the Neonate, [Online], Available: http://www.collegeofmidwives.org/Standards_2004/Standards_MBC_SB1950/Assess_HealthyNeonate_Oct2004_OOO.htm [Retrieved on: 2008, April 2].
- Greene, A. (2007), Neonatal respiratory distress syndrome, [Online], Available: http://www.nlm.nih.gov/medlineplus/ency/article/001563.htm [Retrieved on: 2008, April 2].
- Halamek, L. P. Et al (2006), Continuous Positive Airway Pressure During Neonatal Resuscitation, Clin Perinatol, 33, pp. 83-98. http://www.mdconsult.com/das/article/body/91421747-3/jorg=journal&source=MI&sp=16080552&sid=690389052/N/525142/s0095510805001235.pdf?issn=0095-5108
- Millar, D., & Kirpalani, H. (2004), Benefits of Non Invasive Ventilation, Indian Pediatrics, 41, pp. 1008-1017. http://www.indianpediatrics.net/oct2004/oct-1008-1017.htm
- NGC (2008), Complete Summary, [Online], Available: http://www.guideline.gov/summary/summary.aspx?ss=15&doc_id=6516&nbr=4085, [Retrieved on: 2008, April 2].
- Sehgal A. Et al (2003), Improving Oxygenation in Preterm Neonates with Respiratory Distress, [Online], Available: http://www.indianpediatrics.net/dec2003/1210.pdf, [Retrieved on: 2008, April 2].
- The Merck Manual (2005). Respiratory Distress Syndrome, [Online], Available: http://www.merck.com/mmpe/sec19/ch277/ch277h.html, [Retrieved on: 2008, April 2].
- Tidy, C. (2006), Infant Respiratory Distress Syndrome (RDS), [Online], Available: http://www.patient.co.uk/showdoc/40000462/, [Retrieved on: 2008, April 2].