Newborn Care was written for healthcare workers providing special care for newborn infants in level 2 hospitals. It covers: resuscitation at birth, assessing infant size and gestational age, routine care and feeding of both normal and high-risk infants, the prevention, diagnosis and management of hypothermia, hypoglycaemia, jaundice, respiratory distress, infection, trauma, bleeding and congenital abnormalities, communication with parents
1. Skills workshop:
Oxygen therapy
The flow of gas is measured in litres per
Objectives minute and can be adjusted by turning an
adjusting wheel. A flow rate of 5 litres per
minute is usually used into a head box. A high
When you have completed this skills flow rate wastes gas and cools the infant while
workshop you should be able to: a low flow rate may allow carbon dioxide to
• Use a flow meter with humidifier. accumulate in the head box.
• Use an air/oxygen blender.
• Use a venturi. 11-b The humidifier
• Use an oxygen monitor. It is also important to use a humidifier
• Use a pulse oximeter (saturation monitor). together with the flow meter so that water
• Provide cannula oxygen. vapour can be added to the dry gas (oxygen,
medical air or a mixture). If a humidifier is not
• Provide nasal prong CPAP.
used the infant will breathe very dry gas which
may damage the airways.
A simple humidifier (‘water bubbler’ at room
USING A FLOW METER temperature) is usually used to add water
vapour to the dry gas if a head box or nasal
WITH HUMIDIFIER cannulas are used. Sterile or boiled water
(which has been allowed to cool) is added
to the humidifier bottle until the water level
11-a The flow meter
reaches the full mark. When the water level
It is important to measure the flow rate of gas approaches the empty mark more water must
given to an infant with a flow meter. The flow be added. The water must be changed and the
meter is usually plugged into an oxygen/air humidifier must be cleaned every day or when
blender. However, the flow meter can also be the humidifier is to be used for another infant.
plugged directly into an oxygen wall plug or Dangerous bacteria such as Pseudomonas
the reducing value of an oxygen cylinder. can grow well in water and, therefore, the
humidifier should only be filled with water
2. 218 NEWBORN CARE
when it is being used. The humidifier should air is too low. The dial which controls the
be cleaned with detergent or soap and water, mixture of oxygen and air can be set at
and be allowed to drip dry. The switch on the any combination from 21% oxygen (i.e.
humidifier must be kept on ‘bubbles’ and not pure medical air) to 100% oxygen (pure
‘jet’. The humidifier must be dry during storage. oxygen).
3. The flow meter with humidifier (either
Some humidifiers both warm and humidify
room temperature or warmed).
the gas. These are expensive and are usually
used with a blender. When infants are
given nasal prong CPAP or are ventilated 11-d Using a venturi
via an endotracheal tube (except during If a blender is not available, a venturi can be
resuscitation), warmed, humidified gas must used with a head box. A venturi is cheaper
be used as the high flow rates can cool and than a blender but not as accurate. The
dry out the mucosa. venturi is a short plastic tube to which a pipe
supplying oxygen is attached. The oxygen
passing through the venturi sucks in room air
USING A BLENDER OR and, thereby, mixes the 2 gases. The venturi is
VENTURI usually attached to a head box (oxygen hood).
Some venturis provide a fixed concentration
of oxygen while others can be used to give
Except during an emergency resuscitation, the concentration required. The latter are
100% oxygen from a cylinder or piped source preferred. When using a venturi attached to a
should not be used as pure oxygen is toxic to head box, an oxygen flow rate of 5 litres must
many tissues, especially the retina of the eye. be used. If possible the percentage of oxygen
Whenever possible oxygen should be mixed in the head box should still be accurately
(blended) with medical air using a blender or measured with an oxygen monitor.
with room air using a venturi.
11-c The components of an oxygen/air USING AN OXYGEN
blender
MONITOR
1. The plastic gas pipes: The pipe for oxygen
is usually white while the pipe for medical
Whenever an infant is given oxygen into a
air is usually black. Each pipe ends in a
head box the FiO2 (fraction of inspired oxygen)
steel connector that must be plugged into
must be measured with an oxygen monitor as
a wall gas fitting or a reduction valve on a
too high or too low a concentration of oxygen
gas cylinder. The shape of the 2 connectors
may be dangerous for that infant if it results
differs to prevent the pipe being connected
in too much or too little oxygen in the blood.
to the incorrect source. The oxygen
The FiO2 cannot be controlled accurately with
connector is 6 sided while the medical air
a flow meter alone. If an oxygen monitor is
connector has 2 flat sides and 2 curved
not available then a blender or venturi should
sides. The wall fitting for oxygen is white
be used to determine the approximate FiO2,
and the wall fitting for medical air is grey.
provided a flow of 5 litres or more is used.
2. The blender unit: This, with the gas pipes,
is usually attached to a supporting rail on
the wall. The blender also has emergency 11-e The components of an oxygen monitor
escape valves which operate if the gas 1. The monitoring unit: This is usually
pressure gets too high. An alarm will attached to a rail or stands on a shelf. On
sound if one of the pipes is not plugged the front of the unit is an on/off switch, a
in properly, or the pressure of oxygen or display of the FiO2, high and low settings,
3. SK ILLS WORKSHOP : OXYGEN THERAPY 219
a calibration knob and an alarm light. The A SaO2 above 92% is safe only if the infant is
monitor is powered by batteries that have breathing room air.
to be replaced at intervals. Most models
A saturation below this range may be
have a ‘low battery’ display to warn that the
dangerous to the infant. The measurement
battery is getting flat.
is made by shining a bright light through
2. The oxygen sensor: This is attached to
the skin and then determining the colour of
the monitoring unit by a thin cable. The
the transmitted light on the other side with
sensor is placed in the head box next to the
a sensor. If the blood is red (well saturated)
infant’s head.
the SaO2 reading will be normal or high. A
low reading will be obtained if the blood is
11-f Calibrating the oxygen monitor cyanosed. The monitor also measures the
Place the sensor in room air and switch on the pulse rate by detecting the arterial pulsations
monitor. The display should read 21%. If not, in the small vessels in the skin.
adjust the calibration knob until the display
reads 21%. The monitor should always be 11-h Components of a pulse oximeter
calibrated before it is used. It should also be
The monitor is attached to a skin sensor
calibrated at least daily while in use.
by a thin cable. The monitor is powered by
electricity (via a power cable which plugs
11-g Using the oxygen monitor into a wall fitting) or battery and displays a
First calibrate the monitor with room air. Then pattern of the pulse wave together with the
place the sensor into the head box. The display percentage saturation and pulse rate. A number
should now give the FiO2 in the head box. Set of different designs of sensor are available.
the high and the low alarm limits to 5% above One type looks like a clothes peg and can be
and 5% below the required FiO2. If the display clipped onto the infant’s hand, foot or ear lobe.
falls outside these limits, the red alarm light Another type can be strapped onto a hand or
will come on and the alarm buzzer will sound. foot with tape, while an adult finger sensor can,
Silence the alarm by correcting the air/oxygen with difficulty, be slipped over the infant’s foot.
mixture to the required FiO2. The display A regular pulse wave indicates that the skin
should be read and recorded on the observation sensor is correctly positioned. The pulse wave
chart at regular intervals while the infant is may be displayed as a moving line on a screen
receiving extra oxygen. Remember that the or a digital display of vertically arranged lights.
monitor measures the FiO2 but does not control
the FiO2. The FiO2 cannot be changed by simply 11-i Using a pulse oximeter
adjusting the oxygen monitor!
1. Attach the sensor to the infant’s hand, foot
or ear and then switch on the monitor. It
may take a short while before it displays
USING A PULSE OXIMETER the pulse wave on the screen.
(OXYGEN SATURATION 2. A good, regular pulse wave should be
displayed. If not, adjust the position of
MONITOR) the sensor slightly or move the sensor to
another part of the body.
A pulse oximeter (also called an oxygen 3. Set the upper and lower limits for the
saturation monitor) measures the saturation SaO2 and pulse rate. This is usually done
(amount) of oxygen in the red cells of small by simply pressing the limit buttons. The
arteries under the skin. The result is expressed SaO2 limits are usually set at 86% and 92%
as a percentage and the normal saturation of while the pulse rate limits are usually set to
oxygen (SaO2) in a newborn infant is 86–92%. 120–160 beats per minute.
4. 220 NEWBORN CARE
4. You should now be able to read both the PROVIDING NASAL
SaO2 and the pulse rate on the display
panel. If the pulse wave is poor or the SaO2 CANNULA OXYGEN
or pulse rate is abnormal the alarm will
sound. Press the alarm button to switch off This is the best way of providing an infant
the alarm and take the necessary action. with extra oxygen if CPAP or ventilation is not
required.
11-j Problems with a pulse oximeter
11-k Setting up the equipment needed
1. If the infant moves a lot it may not be poss-
ible to obtain a good pulse wave reading 1. Source of oxygen and medical air which
and the monitor will alarm repeatedly. is mixed in a blender. If a blender is not
2. If the infant’s perfusion is poor it is best to available, 100% oxygen can be used.
attach the sensor to the hand or ear rather 2. A flow meter. The flow rate is set between
than the foot. 0.5 and 1 litre per minute. Do not use high
3. If the infant is receiving phototherapy or is flow rates.
under a bright light, it is preferable to cover 3. A humidifier (bubbler) at room temperature
the sensor with a nappy or piece of cloth as 4. Connecting tubing
the light may interfere with the function of 5. A nasal cannula set. This consists of a loop
the sensor. of tubing with two short nasal cannulas at
the centre of the loop. The nasal cannula
The pulse oximeter should be used when the
set is plugged into the connecting tubing
measurement of SaO2 is needed on a sick
from the blender or oxygen source.
infant. The sensor can be left attached for
6. It is very useful to have a pulse oximeter
continuous monitoring or the sensor can
to make sure that the correct percentage
be attached at regular intervals for a single
oxygen is being given.
reading. The monitor should not be used
simply to obtain the pulse rate. If the pulse
rate recorded by the monitor differs from the 11-l Attaching nasal cannulas
correct heart rate, then the monitor is not The nasal cannula set is slipped over the
functioning properly and, as a result, the SaO2 infant’s head so that both short cannulas sit
displayed may be incorrect. When moving the comfortably in the nostrils. The two tubes
sensor from one infant to another, the sensor are then gently pulled together at the back of
should first be wiped with an alcohol swab to the head. Usually the tubing is taped to the
prevent the spread of infection. infant’s face on either side of the nose. This
NOTE A red and infrared light is used in a pulse will keep the nasal cannulas in place and
oximeter to measure the colour of red cells. Well- prevent them pulling out.
oxygenated haemoglobin absorbs more infrared
light while poorly oxygenated haemoglobin
absorbs more red light. The barr graph indicates PROVIDING NASAL CPAP
when the pulse of arterial blood enters the
capillaries. The oximeter reading is taken at the
height of the pulse and, therefore, reflects the It is important not to attempt to provide nasal
oxygen saturation of arterial blood. A good pulse CPAP unless the medical and nursing staff
is needed to get an accurate reading. have been trained in the correct method to
apply this management.
11-m CPAP apparatus
CPAP is given to the infant with a CPAP
apparatus. This may be made up of individual
5. SK ILLS WORKSHOP : OXYGEN THERAPY 221
parts or bought as a Flow Driver, which is 4. A well-fitting cotton or woollen cap should
a commercial device designed specially for be put in place so that it fits snugly over the
providing CPAP. back of the infant’s head.
5. Choose the correct size nasal prongs which
The components of a CPAP apparatus are:
fit comfortably into the infant’s nostrils. It
1. A blender with air and oxygen pipes to is very important to choose the correct size
connect to the gas source (wall plugs or of nasal prongs which are not too tight as
cylinders). This will allow a choice of FiO2 this can cause damage to the infant’s nose.
between 0.21 and 1.0. An oximeter is very 6. Connect the nasal prongs to the nosepiece.
useful as it accurately measures the FiO2 7. The CPAP nose piece is put into position
being provided. and firmly attached.
2. A flow meter to control the flow of mixed 8. The temperature of the humidifier must be
air and oxygen in litres per minute. Setting set at 37 °C.
the flow rate controls the amount of CPAP 9. The required FiO2 is set and the flow
provided. adjusted to provide CPAP of 5 cm water.
3. A warmed humidifier 10. Monitor the infant carefully with regular
4. A pressure gauge. This allows the pressure observation. This is very important as
(CPAP) to be measured. the nasal prongs can easily be dislodged.
5. Tubing (pipes for the circuit) to connect the Routine suctioning is not needed. If
humidifier to the nose piece. The single tube possible the infant should be monitored
from the humidifier divides into 2 smaller with a pulse oximeter.
tubes, one going to each nasal prong.
6. A special nose piece with interchangeable 11-o Attaching the nose piece
nasal prongs. Three sizes of prongs are
needed. Two small tubes carry the blended A cotton or woollen cap is placed on the infant’s
and humidified air and oxygen mixture to head. Tapes attached to the cap are then tied to
the nose piece while a single larger tube the nose piece so that the nose piece is held in
allows the infant to exhale through the nose place. Tape the ties between the cap and nose
piece. The temperature probe from the piece to the sides of the infant’s face. It helps if
humidifier plugs into the tubing at the point a piece of Stomadhesive, about 1 by 2 cm, is cut
where the single tube divides into 2 tubes. and stuck over the infants cheekbones in front
of the ears on both sides of the face. The tubing
A cotton or woollen cap with tapes to hold the can now be taped to the Stomadhesive pieces.
nose piece in position, as well as strapping to This protects the infant’s skin.
attach the tubing, is needed.
The 2 inflow tubes should rest on a roll of
cotton stocking placed on top of the infant’s
11-n Setting up the CPAP apparatus
head. The cotton roll is taped to the top of
1. Place the infant supine (back lying on the the cotton cap. The small tubes can now be
bed) under an overhead radiant heater or strapped to the cap to help keep the nose piece
in a close incubator. in place if the infant moves her head.
2. It is useful to place a small rolled-up nappy
under the infant’s shoulders to get the head 11-p Managing an infant on nasal CPAP
and neck in the correct position.
3. The infant should not be fed and an 1. Record the infant’s respiratory rate,
orogastric tube should be passed and kept heart rate, colour, presence or absence
on open drainage to prevent abdominal of recession or apnoea. Record the pulse
distension. An intravenous infusion is oximeter reading if available.
needed.
6. 222 NEWBORN CARE
2. Check that the nasal prongs are in position 5. Only suction if needed.
and make sure the nasal prongs are not too 6. If necessary the CPAP pressure can be
tight. increased to 8 cm water.
3. Check the temperature and water level 7. Wean both the CPAP pressure and FiO2 as
of the humidifier and remove any excess the infant improves clinically.
water from the tubing.
Do not provide nasal CPAP unless the staff
4. Adjust the FiO2 if needed.
have received appropriate training.