Page 9 - 58peadiatric-surgery-speciality1-7_opt

Neonatal Physiology and Transport 11
when TPN is unavailable. As getting energy and substrate into the against infection are breached, usually by a well-intentioned physician.
patient is a priority, there may be no alternative to adjusting surgical Thus, intravenous cannula placement, urinary catheter insertion,
strategy to allow early use of the alimentary tract. This may involve endotracheal intubation, and orogastric intubation all bypass important
placing feeding tubes distal to, or through, an anastamosis or creating defence structures. Thought must be given to the necessity of these
a stoma above, or instead of, an anastamosis. An extracorporeal interventions because each has an inherent risk. When deemed essential,
gastrointestinal bypass can be created by aspirating bile-containing all interventions must be performed aseptically. Tubes and catheters
fluid from above an obstruction and returning it with a feed either via should be removed as soon as practicable. It is not possible to make up
a stoma or via a trans-anastamotic tube, distal to the obstruction. Even for deficiencies of hygiene by prescribing antibiotics.
when full feeds are not tolerated, there is merit in providing “trophic” Clearly, antibiotics do have a place in the management of infection
or “trickle” feeds that maintain the integrity of the intestinal mucosa. 15 but the importance of fungal and viral sepsis must be remembered. The
The advent of the human immunodeficiency virus (HIV), particularly more premature the patient, and the longer the intensive care unit (ICU)

the recognition of the seroconversion of breast-fed babies, has added a stay, the greater must be the clinical suspicion of fungal sepsis, even
16
further confounding variable. Breast milk is the best, cheapest, and when cultures are not possible.
generally most readily available feed for babies, and it is ideal for the
surgical patient. These advantages must be weighed against the risk of Neonatal Transport
transmission of HIV and the economic circumstances of the family. It The centralisation of neonatal surgical services has made neonatal
17
should be remembered that breast milk contains lactose and that many transportation 25,26 inevitable. From the outset it must be recognised
gastrointestinal disorders result in temporary lactose intolerance with that transportation is not good for babies; it adds to their stress and
resulting diarrhoea. 18 represents a break in the continuum of care. Neonatal transportation is
The term neonate requires about 120 kCal/kg per day to maintain an exercise that demands the highest professionalism and planning and
health. The surgical neonate, after a very brief postoperative increase should only be undertaken in close cooperation with the unit receiving
19
in metabolic rate that lasts only four to six hours, may require fewer the infant. Formal training in transportation skills is provided in most
calories than normal due to immobility and growth inhibition as well US paediatric training programmes, but forms only a small part of the
as reduced thermogenesis. Providing too many calories (overfeeding) undergraduate or postgraduate training in most African schools.
20
may increase CO production from lipogenesis. In the Third World, conflicting health care agendas transpire to limit
2
The premature baby has an increased caloric requirement, up to 130 the human and material resources allocated to interhospital transport.
kCal/kg per day. 21 This is something of a false economy, as the inexpert transport of a baby
Hypoglycaemia results in either a death on arrival (DOA) or delivers a patient in whom
SGA infants, those with diabetic mothers or who have specific conditions resuscitation and avoidable morbidity adds to the cost of management.
Care in transport is also compromised by the infrequency with
such as Beckwith-Wiedemann syndrome are at risk of hypoglycaemia in which any individual medical officer is required to effect transfer, and
the first few hours of life. Failure to recognise hypoglycaemia will result the small proportion of his practice that this involves. This lack of
in unnecessary neurological morbidity. Clinical signs include apnoea, the familiarity often leads to unseemly haste in attempting to get a baby to
tremors or jitteriness, followed by convulsions. The blood sugar should a tertiary centre. Speed is never an issue; care is.
be kept above 2.2 mmol/l by infusion of 10% dextrose if necessary. The In an ideal world, the baby would be stabilised in the ICU at
blood sugar level should be monitored in all at-risk babies.
the referring hospital, and transported by dedicated medical and
Hyperglycaemia paramedical staff in a mobile ICU to the welcoming staff of the ICU at
The stress response results in hyperglycaemia in many neonates the referral hospital. It is, however, not an ideal world.
22
with emergency surgical conditions, and is common after surgery. Fortunately, most surgically ill babies require minimal technological
Premature babies appear to have a higher normal blood sugar, and support during transport, and there is much that can be done without
moderate degrees of hyperglycaemia (blood glucose < 15 mmol/l) can recourse to mobile ICUs and high technology. Most transferred babies

be tolerated. Glycosuria with a resultant osmotic diuresis occurs only have some form of intestinal obstruction and require little other than
with glucose levels around 12 mmol/l due to greater renal retention in gastric decompression, intravenous fluid, and temperature maintenance.
the premature infant. Incubators and other devices that rely on electricity or batteries,
Immune Function which always seem to be flat when needed, are not essential. Heat
and fluid loss can be minimised by wrapping exposed viscera in
The normal intrauterine environment is sterile, and the neonate has lim-
clear plastic sheeting such as can be found in most kitchens, or, when
ited exposure to antigens before birth. Both the B-cell and T-cell popu-
necessary, a plastic shopping bag. A warm baby can be kept warm by
lations are naïve, and the neonate depends primarily on the “innate” or
enveloping him in an insulating blanket of aluminium foil, another
nonspecific functions of the immune system.
Circulating neutrophils have a half-life of around 8 hours and must kitchen accessory. It is important to include the head, which represents
be constantly replenished to effectively combat infection. However, a large proportion of the surface area and contributes significantly to
the neonate has a low bone marrow storage pool of neutrophils, and heat loss, but not the face.
although they are functionally competent, they respond poorly to Denim bags containing mung beans or any grain, heated for 1
chemotactic stimuli and are rapidly consumed. The neonate also has minute in a microwave oven, can provide sufficient heat to keep a

23
deficiencies in the complement system. Almost all immunoglobulin neonate warm for two hours during transport, or, more traditionally, hot
water bottles (held remote from the skin to prevent burns) can be used.
at birth is maternally derived immunoglobulin G (IgG). This
Portable incubators that have hot water bottles as their source of heat
immunoglobulin has a half-life of around 3 weeks. Immunoglobulin
were the standard of care when New York City introduced a transport
M (IgM) production is very limited. Immunoglobulin A (IgA), the
24
mucosal surface immunoglobulin, is acquired from breast-feeding. service for premature babies in 1948. That principle is still sound.
An incubator is just a transparent box designed to keep a baby warm.
The naïve T-cell population exposes the neonate to the risks of viral
The heat it provides is no better than the heat provided by mung beans or
and fungal infections, and the “lazy” leukocyte population means that
hot water, and it is certainly more expensive. We re-emphasize that there is
infections are poorly localised and septicaemia is frequent.
Thus, the neonate is immunodeficient when compared to adults. a difference between keeping a warm baby warm, which is what is required
This deficiency becomes more apparent when the nonspecific defences during transport, and making a cold baby warm, which is something