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
Skills workshop: Measuring jaundice and using phototherapy
1. Skills workshop:
Jaundice and
phototherapy
concentration (Hb), i.e. a PCV of 30% would
Objectives be expected if the Hb was 10 g/dl.
9-a Equipment that is needed to collect a
When you have completed this skills sample of capillary blood
workshop you should be able to:
1. A plastic dish of warm water or a warm,
• Collect a sample of capillary blood.
wet towel.
• Use a microcentrifuge. 2. An alcohol swab or gauze swab soaked
• Measure the packed cell volume. with surgical spirits.
• Use a phototherapy unit. 3. A jar of Vaseline (petroleum jelly).
4. A sterile lancet.
5. A container for sharps.
6. A heparinised 75 mm capillary tube.
MEASURING THE PACKED 7. Plasticine.
8. A dry swab to stop the bleeding.
CELL VOLUME 9. A pair of gloves if HIV is common in the
community.
The packed cell volume (PCV or haematocrit)
is the percentage of red cells in a sample of 9-b Collecting a blood sample to measure
whole blood. The normal packed cell volume the packed cell volume
is 45 to 65% at birth (i.e. just over half the
volume of blood consists of red cells). In the The packed cell volume may be measured
newborn nursery the packed cell volume, on a sample of arterial, venous or capillary
rather than the haemoglobin concentration, is blood. If capillary blood is used, very careful
measured as it is more accurate. It is also more attention must be paid to the correct method
convenient as often the blood has to be spun of collecting the sample. Usually blood is
in order to measure the total serum bilirubin sampled from the infant’s heel. The infant’s
concentration. The packed cell volume is foot must be warm so that the blood flows
approximately 3 times the haemoglobin easily without the need to squeeze the heel.
If the heel is cold and has to be squeezed, an
2. SK ILLS WORKSHOP : JAUNDICE AND PHOTOTHERAPY 179
incorrectly high-packed cell volume reading It is best to always use gloves when collecting a
may be obtained. blood sample.
The method of obtaining a capillary blood A safety lancet is expensive and only used
sample for a packed cell volume measurement once. However, it avoids the risk of a ‘needle
is as follows: stick injury’.
1. If possible, the infant’s foot should be placed
in a plastic dish of warm (not hot) water or 9-d Using a microcentrifuge
wrapped in a warm towel for 1–2 minutes. The sample of blood in the capillary tube
2. Dry the foot, clean the skin with an alcohol must be spun down in a microcentrifuge for
swab and smear a thin layer of Vaseline 2 minutes. All level 2 and 3 nurseries should
over the heel. have a microcentrifuge.
3. Pierce the skin with a lancet and then
immediately place the lancet in the sharps A microcentrifuge should be used as follows:
container. 1. The power lead can be left plugged in and
4. A large drop of blood should form on switched on all the time.
the skin. Touch the drop of blood with a 2. Open the lid of the microcentrifuge and
heparinised glass capillary tube and the unscrew the cover.
blood will run into the tube if it is held 3. Place the capillary tube in one of the
horizontally or slightly downwards. radiating grooves in the centrifuge plate so
5. Close one end of the capillary tube with that the end of the tube, which is blocked
plasticine. with plasticine, is right up against the
6. Stop the bleeding by applying pressure outside edge of the plate. Many capillary
with a dry swab for a few minutes. tubes can be centrifuged (spun) at the
same time if needed. The capillary tube
9-c Do not prick your finger by mistake must be balanced by another tube (filled
with water if necessary) placed in the
Be very careful not to prick your finger by
groove opposite it.
mistake when obtaining a sample of capillary
4. Replace the cover and screw it tightly
blood from an infant. Immediately after
closed.
piercing the infant’s skin, the lancet must be
5. Close the lid.
placed in a special container for ‘sharps’. It is
6. Set the timer for 2 minutes.
very important to dispose of the lancet as soon
7. Switch the microcentrifuge on.
as possible as it is very easy to prick yourself
8. After 2 minutes the microcentrifuge will
while removing the used equipment after
automatically switch off. Allow it to stop.
the procedure. Therefore, never leave a used
Some microcentrifuges can be manually
lancet or needle lying exposed. Viruses such
slowed down with a brake.
as hepatitis B and HIV can be transmitted as a
9. When the microcentrifuge has stopped
result of a finger prick with a lancet or needle
completely, open the lid, unscrew the cover
if the patient is infected.
and remove the spun capillary tube.
You will notice that the red cells have all been
Place the lancet in a special container for ‘sharps’ spun to one end of the tube. The rest of the
immediately after piercing the skin tube is filled with serum. Where the red cells
and the serum meet, you will see a 1 mm white
If possible, clear plastic rather than glass band. This is formed by the white blood cells.
capillary tubes should be used. This avoids the
risk of a tube breaking in the microcentrifuge.
Blood-stained broken glass is dangerous as it
may cut the operator’s finger and spread HIV.
3. 180 NEWBORN CARE
9-e Determining the packed cell volume 9-f Using a bilirubinometer
A special instrument called a packed cell Before the total serum bilirubin (TSB) can be
volume reader (or a micro-haematocrit measured with a bilirubinometer, a sample
reader) is used to measure the packed cell of blood has to be collected into a capillary
volume. Two different types of PCV reader tube and spun down as described above. A
are available. One type measures the PCV number of different types of bilirubinometers
while the capillary tubes are still in the are available. Some measure the TSB in the
microcentrifuge while the other type is serum while still in the capillary tube. Others
completely separate from the microcentrifuge. require that the tube has to be snapped
at the junction of the serum and the red
Measuring the packed cell volume on the
cells so that the serum can be run into a
microcentrifuge:
special glass measuring chamber. This type
1. Centrifuge (spin) the capillary tube as is dangerous if the HIV prevalence in the
described above. community is high as it is very easy to cut
2. Place the perspex reader over the plate one’s finger when snapping a glass tube. It is
holding the capillary tubes. safest to use clear plastic capillary tubes with
3. While holding the plate still with one hand a bilirubinometer which measures the TSB
so that it does not turn, twist the knob on in intact tubes. Both types of bilirubinometer
the reader with the other hand until the are electrically powered, expensive and have
baseline (i.e. 0) crosses the capillary tube to be carefully standardised at least once a
at the point where the red cells meet the week. The care and use of a bilirubinometer,
plasticine. therefore, should be the responsibility of a
4. Now hold the knob still with one hand and trained medical technologist. Staff wishing
rotate the perspex reader with the other to use a bilirubinometer should get personal
hand until the top line (i.e. 100%) crosses instructions from the local technologists. The
the capillary tube at the top of the serum method is simple but differs depending on the
(not the top of the tube). model of bilirubinometer available.
5. Determine which line crosses the capillary
tube at the point where the red cells meet
the serum. Follow that line along to either USING A PHOTOTHERAPY
the left or the right and read the PCV.
UNIT
Measuring the packed cell volume off the
microcentrifuge:
A phototherapy unit is used to provide a source
1. Remove the capillary tube from the micro- of bright light to treat jaundice in newborn
centrifuge and place it in the vertical infants. The light alters the bilirubin in the skin
groove of the reader so that the junction of of the infant allowing the infant’s liver to excrete
the plasticine and the red cells lies on the the bilirubin which is now water soluble.
bottom line.
2. Slide the capillary tube holder to the left or 9-g Components of a phototherapy unit
the right until the top line falls on the top
of the serum (not the top of the tube). A number of commercial or hospital-made
3. Move the perspex arm up so that the line phototherapy units are available. Usually they
falls on the junction of the red cells and the have fluorescent tubes although some have
serum. white halogen or blue LED (light emitting
4. Read the PCV. diode) spot lights. The main components of a
fluorescent tube phototherapy unit are:
1. The fluorescent tubes: Most phototherapy
units contain 4 or more white or blue
4. SK ILLS WORKSHOP : JAUNDICE AND PHOTOTHERAPY 181
fluorescent tubes. Increasing the number close. Some phototherapy units also have
of fluorescent tubes improves the efficiency a platform on which to stand the bassinet.
of the phototherapy. Ultraviolet tubes are Others can be moved over the incubator
never used as they will burn the infant or bassinet. The stand should be as small
very seriously. Usually 60 cm long white as possible so as not to take up too much
‘Daylight’ tubes are used (labelled SABS space in the nursery or ward. Sometimes
No. 2; SABS stands for South African more than one phototherapy unit is used
Bureau of Standards). Daylight tubes are for an infant with a high TSB.
also used in hospitals for lighting rooms
Some overhead radiant heaters (intensive
and passages. To increase the amount of
care cribs) have white halogen spot lights or
blue light produced by the phototherapy
blue LED spotlights which can be used to give
unit, Daylight tubes are often mixed
phototherapy.
with special blue tubes (Tl 20 Watt/03T
produced by Philips). Fluorescent tubes
have a limited life span and, therefore, 9-h Setting up for phototherapy
must be replaced every 1000 hours (or 1. The infant must be fully undressed. Do not
6 months if the hours in service are not leave the nappy on as this covers a large
recorded). A special photometer can be area of skin. It is safe to leave the genitalia
used to measure the light output of a exposed under phototherapy.
phototherapy unit. This helps in deciding 2. The eyes should be covered for comfort.
when to replace the tubes. It is safe to remove the eye covers during
2. The light box: The fluorescent tubes are feeds even if the infant remains under
fixed into a special light box which usually phototherapy.
has a fan to keep the tubes cool. Otherwise 3. Do not cover the infant with a sheet or
the tubes and the infant will overheat. Most blanket.
light boxes have a time counter which 4. Make sure that the infant is not in a draft
indicates how many hours the tubes have (near an open door or window).
been used. 5. The phototherapy lights are usually set at
A thick sheet (1 cm) of clear perspex about 40 cm above the infant.
(plastic) must be placed under the tubes to 6. Milk feeds should be continued unless
protect the infant from falling glass if a tube there is a contraindication. Extra clear feeds
explodes. The perspex does not lessen the are not necessary. Unless the TSB is very
effect of the phototherapy but it does reduce high, breast milk feeds can be continued.
the amount of heat reaching the infant. 7. The infant’s skin temperature should be
recorded every 3 hours. Lying undressed
3. The stand: All phototherapy units have under phototherapy can result in either
some form of stand to support the lighting hypothermia or hyperthermia.
box. Usually the stand allows the height 8. The infant should be weighed every
of the light box to be raised or lowered. 12 hours. Weight loss is the best clinical
The tubes usually are placed 40 cm above guide to dehydration.
the infant. The closer the tubes are to the 9. The infant is often turned onto the
infant the more effective is the treatment abdomen or back after each feed. However,
as more light is provided. Therefore the this has not been shown to increase the
tubes are often moved closer if the infant effectiveness of phototherapy.
is severely jaundiced. However, the infant 10. Make sure that the mother can visit or stay
may overheat if the tubes are brought too with her infant during phototherapy.