postgraduate surgery presentation

1. Intensive care in neonates
Presenter: Dr PASHI
Moderator: Dr Bvulani
22/09/16

2. Introduction
• Neonatal intensive care unit (NICU) - specialised care offered to ill or
premature newborn infants
• NICU and surgery have helped improve the survival of neonates with
various conditions
• These conditions include, but are not limited to, prematurity, low
birthweight, congenital anomalies, and other medical issues

3. Neonatal Classifications
• Neonate : Newborn baby in the first 4 weeks of life
• Gestational Age (GA)
Premature - < 37 weeks
Term – 37 to 42 weeks
Post term - > 42 weeks
• Weight Vs Gestational Age
Small for GA – weight lies below the 10th percentile for GA
Appropriate for GA – weight lies between 10th and 90th percentile
Large for GA – weight lies above 90th percentile for GA

4. Neonatal classification ctd
• Premature
Moderately low birth weight (82%) – 1501 to 2500g
Very low birth weight (12%) – 1001 to 1500g
Extremely low birth weight (6%) - < 1000g
• Intrauterine Growth Retardation (IUGR)
• Documented decrease in intrauterine growth noted by ultrasonography
1. Symmetric IUGR – normal body proportions
2. Assymetric IUGR – small abdominal circumference, decreased subcutaneous
and abdominal fat, reduced skeletal muscle mass, normal head circumference

5. Neonatal Problems
IUGR Preterm
Hypothermia Hypothermia
Hypoglycaemia Respiratory distress syndrome
Polycythaemia Poor oro-motor coordination
Meconium aspiration Patent ductus arteriosus
Jaundice Necrotising enterocolitis
Intraventricular haemorrhage

6. Neonatal problems ctd
 Assessment of gestational age can be done
Antenatally – Ultrasonography
First days after birth – Ballard score (assesses general and physical maturity)
 Birth weight and GA – strong indicators of mortality
 Preterm infants suffer physiologic handicaps
Functional immaturity
Anatomic immaturity

7. Resuscitation at birth
• Resuscitation at birth is a relatively frequent occurrence.
• Approximately 10% of newborns will require help to establish
breathing at birth, with 1% requiring more extensive resuscitation
• Two broad categories identified:
Those who have undergone a period of hypoxic stress in utero,
and
those who are prone to hypoxaemia in the immediate postnatal
period due to inadequate pulmonary development, airway
obstruction or congenital malformations.

8. Goals of Neonatal Intensive care
• Vary depending upon the status of the infant
• To return the infant to its normal state of health e.g extremely
premature infants
• To find the balance between undertreating and overtreating the
infant e.g. infants with defects or conditions where intensive care may
only increase suffering, prolong the act of dying, or result in survival
with significant burdens

9. NICU admission criteria
• Admission to NICU should be routine for the following babies:
• • Less than 34 weeks
• • Less than 1.7kg
• • Respiratory distress
• • Poor condition at birth requiring resuscitation (consider admission if the cord pH is less
than 7.0)
• • Congenital abnormalities likely to threaten immediate survival
• • Seizures
• • Cyanosis
• • Sepsis
• • Jaundice, requiring intensive phototherapy
• • Any other babies where there are substantial concerns

10. Monitoring
• Intensive care unit environment offers continuous monitoring
• Monitoring enables assessment of
• impact of intensive care unit intervention
• characterize the nature and significance of derangements
• Monitoring strategies are designed to follow individual organ function
and, to a lesser degree, the interaction between systems.

11. Parameters Monitored - NICU
• Available devices can analyze
• physical parameters (pressure, temperature, flow, volume),
• electrical function (EEG, ECG, train-of-four),
• gas dynamics (saturation, partial pressure),
• concentrations (hemoglobin), and
• chemistries (microdialysis).
• Monitors are limited in their ability to interrogate tissue health and
cellular function.

12. Monitoring - Interpretation of readings
• Measurements should be interpret carefully
• considering population norms,
• baseline patient capability,
• demands of the physiologic circumstance, and tolerance of
deviations from “optimal” or “normal” function

13. General principles of ICU management
Goals in surgical neonate
• Stabilisation
• Pre-operative assessment and management to determine ability to
cope with surgery.
• While the surgery may be relatively short, its success will depend
upon the calibre of both pre- and post-operative care.

14. Thermoregulation
Prevention of hypothermia
• This is well recognised and compensated for in NICU
• Transportation vehicles/operating theatres usually not well adapted
and the temperature will need adjustment.
• The baby’s core temperature should be maintained at 37°C with
peripheral temperature maintained at 36°C
• Thermoneutral temperature – T maintained with minimal metabolic
rate
• Critical Temperature – metabolic response to cold to replace lost heat
• Incubator T determined by Weight and Postnatal age

15. Thermoregulation - embryology
• 5-35 weeks gestation - Hypothalamic function matures
• Regulates T control
• Regulates pituitary gland hormones
• 20 wks onwards - Brown fat is formed
• 23-24wks GA – fetal lung can support gas exchange
• 26wks GA - developed keratinised stratum corneum with thin
epidermis
• 34 wks GA – epidermal development is complete

16. Thermoregulation-Heat production
• Term baby initiates thermal control at birth
• Thermogenesis is initiated by 3 different mechanisms:
1. cutaneous cooling
2. oxygenation
3. separation from the placenta
• Non shivering thermogenesis
• Brown fat metabolism – primary source of heat
• Hepatic glycogenolysis

17. Thermoregulation-Heat production ctd
• The mechanisms of non-shivering thermogenesis include
the metabolism of brown adipose tissue
the secretion of noradrenaline and
the release of thyroxin

18. Thermoregulation- inhibitors
• Brown fat thermogenesis is inactivated
• Vasopressors
• Anesthetic agents
• Nutritional depletion
• Infants undergoing laparotomy are at increased risk from heat loss
directly from exposed bowel.
• Aqueous rather than alcohol-based skin preparations - reduce
evaporative heat loss.

19. Thermoregulation – Heat loss
• Heat loss is by
Evaporation
Conduction
Convection
Radiation

20. Thermoregulation – Heat loss
• Surgically ill neonates lose heat by
• vomitus,
• tachypnoea
• when undergoing laparatomy
• evisceration at birth (gastroschisis or ruptured exomphalos)

21. Respiratory system - embryology
• Bhutani (2006), lung development can be divided into 7 stages
• 5 fetal stages, a neonatal period of approximately 2 months to full
lung development by approximately 8 years
• 1. The embryonic stage (0–7 weeks’ gestation)
• 2. The pseudoglandular stage (8–16 weeks’ gestation)
• 3. The canalicular stage (17–27 weeks’ gestation)
• 4. The saccular stage (28–35 weeks’ gestation)
• 5. The alveolar stage (>36 weeks’ gestation)

22. Respiratory system-Surfactant
• Produced by the alveolar type II cells
reduce the surface tension in the lungs aiding gaseous exchange
prevents the alveoli from collapsing completely (atelectasis) at the end of expiration
Helps to reduce the work of breathing for the infant
• Factors that stimulate synthesis
glucocorticoids
Catecholamines also increase surfactant
• Factors that inhibit synthesis
Insulin
Hypothermia
acidosis

23. Respiratory system at birth
• Stimulus of first breath:
• Clamping/obstructing the umbilical cord results in an ‘asphyxial’ event
• cooling – sudden drop from intra-uterine temperature
• physical discomfort from touching and drying
• Neonates : obligatory nasal breathers & obligatory diaphragmatic
breathers
• Alveoli in the neonatal lung < 10% of the adult quota
• new alveoli are continually added up to 8 years of age

24. Respiratory function
• Assessment of respiratory function is a prerequisite for all surgical
neonates as urgent intervention may be required.
• Anatomical abnormalities/increasing abdominal distension -
compromise ventilation.
• Surfactant deficiency or aspiration pneumonia may contribute
• The extent of respiratory support required depends upon clinical and
radiological findings and blood gas analysis

25. Respiratory support levels
• Infants with mild Respiratory Distress Syndrome (RDS)
• with good respiratory effort
• and effective ventilation
only require supplemental oxygen to manage their condition
O2 delivered through nasal cannula, via the incubator or a head box or hood
• Infants who display an increase in their work of breathing
• associated with hypercarbia
• and an increase in oxygen requirements will benefit from increased
• reasonable spontaneous respiratory effort with mild hypercarbia
Respiratory support in the form of CPAP
• Infants with decreased respiratory drive or apnoeas with a raised PaCO2
and reduced PaO2 will need to be intubated and ventilated

26. Respiratory support trauma
Ventilation in the neonatal period can result in lung injury
• increases risk of respiratory morbidity including air leak and chronic lung disease.
• Proposed mechanisms for ventilator induced lung injury (VILI):
• Volutrauma - alveoli are over-distended by the delivery of too much gas.
• Barotrauma - alveoli are subjected to high pressures causing alveolar disruption
• Biotrauma due to injurious effects of inflammation, infection and oxidative stress.
• Atelectotrauma - alveolar collapse at the end of expiration requiring re-
recruitment with every breath.
• Stretch trauma - rate of inflation of the alveoli is beyond their normal elastic
capability.

27. Respiratory support trauma ctd
• The modern trend in ventilating preterm newborns is to provide
the gentlest invasive ventilation possible for the shortest time
possible.
allowing permissive hypercarbia
and permissive hypoxaemia

28. Respiratory Support Target readings
• Acceptable blood gas results for infants requiring respiratory support
Parameter Normal Ventilated preterm infants Term targets
Targets with permissive
hypercarbia and permissive
hypoxia
pH 7.35–7.45 >7.25 7.3–7.4
PaCO2 4.5–6 kPa 6–7.5 kPa 4.5–6 kPa
Arterial PaO2 11–14 kPa 7–12 kPa >8 kPa
SaO2 100 per cent 90 per cent >95 per cent

29. Respiratory support Types
1 - Non-invasive – Continuous Positive Airways Pressure (CPAP)
• Deliver a predetermined continuous pressure and supplementary oxygen
to the airways of a spontaneously breathing infant (Jones and Deveau
1997)
• mechanically splinting the airways open
• Reduce upper airway occlusion and
• decreases upper airway resistance
• Improves ventilation
• recruiting collapsed alveoli
• increasing the surface area available for gas exchange
• Stabilises the chest wall and reduces the work of breathing.

30. Respiratory support Types ctd
CPAP delivery
• Nasal CPAP (nCPAP) prongs are the most commonly applied means of
delivering CPAP (Gomella 2004)
• Newborn infants are inherent nasal breathers
• nCPAP is easily facilitated and well tolerated
• Binasal (double) prongs are more widely used than single prongs
• Nasal prongs have been associated with erosion
• Need to be carefully sized before insertion into the infant’s nares

31. Respiratory support Types ctd
2. Invasive Ventilation
• Ventilatory support optimised by monitoring interaction between infant and
ventilator
• Allow infant-regulated breath-by breath changes in peak pressures, tidal
volumes, inspiration times and rate
• help reduce the ventilator induced lung injury (VILI)
• Types
• Continuous mandatory ventilation (CMV)
• Volume control (VC)
• Assist control ventilation (A/C)
• Synchronised intermittent mandatory ventilation (SIMV)

32. Gastric decompression
• Intestinal obstruction and/or sepsis predispose the infant to increased
gastric secretions
• Gastric decompression
avoid vomiting and aspiration pneumonia
reduce splinting of the diaphragm and aid ventilation.
• Correctly positioned naso-gastric tube large enough to prevent
blockage (8fg or greater)
• The tip of the tube should be in the stomach and left on continuous
open drainage with gentle intermittent aspiration

33. Fluid and electrolyte balance
• Surgery can exacerbate physiological imbalances in the newborn.
• Continuous assessment and monitoring is essential of
perfusion,
parenteral fluid and electrolyte requirements and
metabolic response to surgical trauma.
• Some infants will need fluid resuscitation pre-operatively – exposed
viscera in gastroschisis and examphalos.
• Losses via the naso-gastric tube should be measured and replaced
with normal saline with added potassium.

34. Fluid and electrolyte balance ctd
• The stimulus of surgery and intermittent positive-pressure ventilation
(IPPV) lead to increased aldosterone and antidiuretic (ADH) secretion
resulting in water and sodium retention.
• It may therefore be pertinent to restrict fluid and sodium post-
operatively

35. Acid Base Balance
• Alterations in acid base balance can be caused by several factors.
• Respiratory acidosis occurs with inadequate ventilation, for example, in
pulmonary hypoplasia secondary to congenital diaphragmatic hernia.
• Metabolic acidosis can occur when
bicarbonate losses are increased
poor tissue perfusion,
tissue necrosis, infection,
hypovolaemia
intestinal fistulas and necrotising enterocolitis (NEC).
• The commonest cause in the ‘surgical neonate’ is hypovolaemia which requires
fluid replacement for its correction.
• Correction with bicarbonate should be cautious, as it may cause hypocalcaemia
(Haycock 2003).

36. Nutrition
• Total parenteral nutrition allows delivery of nutritional substrates
directly into the circulation
 During prolonged pre-operative stabilisation,
conditions predisposing paralytic ileus,
• It promotes anabolism and provides for normal growth and
development until gut function is restored.

37. Nutrition ctd
• Glycogen is a skeletal muscle and hepatic storage carbohydrate and is
metabolised when blood glucose falls outside the homeostatic range
(Kotoulas et al. 2006).
• Neonates have poor glycogen stores due to decreased availability of
substrate in utero, and therefore need a constant glucose intake.
• It is essential that dextrose should be administered and the blood
glucose monitored frequently, maintaining a level of 2.6–5.0mmol/L
(Nicholl 2003).

38. Cardiovascular System
• A neonate’s blood volume is approximately 80ml/Kg body weight.
• A 2kg infant has a circulating volume = average loss during minor adult sgy
• Foetal Circulation is associated with
(1) the ductus venosus
(2) the foramen ovale
(3) the ductus arteriosus and including
• high resistant pulmonary vascular system due to the collapsed lungs, and a
• low-resistance systemic circuit

39. Cardiovascular System ctd
• At birth, haemodynamic changes occur in the transition from fetal to
ex-utero circulation due to
• clamping of the placental blood flow and
• the expansion of the lung fields
• Cardiac abnormalities can be primary (congenital), maladaptive at
birth or acquired (secondary)

40. Haematological disorders
• Coagulation status should be assessed pre-operatively and treated
accordingly.
• Assessment should involve those with liver pathologies and suspected
heamoglobinopathies
• The neonate is deficient in vitamin K
• May be given either subcutaneously or intramuscularly
• In an emergency, it can may given intravenously but close observation will be
required for anaphylaxis (Beers et al. 2006)

41. Haematological disorders ctd
• Neonates with severe sepsis or NEC may develop disseminated
intravascular coagulation (DIC) with associated thrombocytopenia
(Puri and Sureed 1996; Stokowski 2006).
• Correcting underlying disease process triggering the condition is key
• Clotting factors should be replaced by transfusion with appropriate
blood products.

42. Haematological disorders ctd
• Concurrent treatments to control the haemorrhage/clotting cycle
include the administration of
• Cryoprecipitate increases Factor VIII and fibrinogen levels
• fresh frozen plasma (FFP), FFP can increase coagulation factors by 15–
20 per cent
• Platelet infusion of 10ml/kg can increase the platelet count by up to
100000/mm3 (Emery 1992; Kenner et al. 1993; Kuehl 1997).
• Exchange transfusions may be used to ‘wash out’ any toxins in the
infant’s blood and to replace clotting factors.
• Vitamin K may also be given.

43. Vascular access
• A central venous line is highly recommended for prolonged venous
access because
last longer
safely infuse fluids known to have a local irritation or sclerosing
effect.
• Peripheral cannulae for administration of medications and blood
product transfusion when necessary.
• Arterial access is also helpful to monitor haemodynamic, biochemical
and respiratory status.

44. Pharmacological support
• There is a risk of sepsis whenever surgery is performed, especially in
intra-uterine growth restriction (IUGR) and preterm babies with
immature immune systems.
• Untreated infection promotes deterioration of the respiratory and
cardiovascular systems and prophylactic antibiotic therapy can reduce
this risk.
• However, continual review of the course of treatment is essential to
minimise the eventual microbial resistance to antibiotic therapy over
time (Kolleff and Fraser 2001).

45. Pharmacological support ctd
• Inotropes are often necessary to improve cardiac function, thus
improving organ perfusion. Dopamine, dobutamine and adrenaline
are the most commonly used inotropes in hypotension in neonates.
• Pain relief is an important consideration both pre- and post-
operatively.
• Cellular damage, particularly in cases of NEC, release pain-producing
substances, augmenting the perception of pain (Brophy 2007).

46. Anaesthetic effects
• Neonates are sensitive to the respiratory depressant effects of opiates
hence require Intubation and ventilation
• Effective analgesia via an epidural catheter can be provided without
depressing respiration (Reynolds 2005)
• suitable for all surgical procedures below the umbilicus
inguinal herniotomy,
Lower limb surgery
genito-urinary surgery

47. Transportation
• The critically ill neonate can make several potentially hazardous
journeys
from the delivery room to NICU,
 interhospital referral
to and from the operating theatre.
• Safe transportation demands collaboration between a doctor and
nurse experienced in neonatal intensive care, and a specialist
anaesthetist for the return journey from theatre.
• It is suggested that utilisation of specialist staff at this time reduces
‘disasters’ such as aspiration, hypothermia and airway obstruction

48. Post-operative considerations
• Management in the post-operative period mirrors the pre-operative
care in achieving and maintaining physiological stability, but in
addition the factors listed below need careful consideration.
• Do not leave the operating theatre until the baby is stable.
• Doctor and anaesthetist should be in attendance in return journey to NICU
• Before returning the baby to the incubator and ventilator, check the settings,
then reconnect fluids and monitor leads to static equipment
• Adjust maintenance and arterial line fluids. Commence NG replacement
losses if necessary. Titrate sedation and epidural infusions as appropriate.
Observe entry sites
• Attach naso-gastric tube to drainage bag

49. ctd
• As soon as possible record:
• core temperature then 4-hourly until stable
• blood sugar then 1–2-hourly until stable
• ventilator settings then 1-hourly until stable
• blood pressure continuous read-out, but record hourly
• heart/respiratory rate
• Attach peripheral temperature probe and maintain temperature above
34°C
• Organise a chest X-ray if the baby was intubated in theatre, there is a chest
drain in situ and following diaphragmatic hernia repair
• Check blood gas and repeat as necessary

50. ctd
• Record urinary output – attach urine bag or weigh nappies – expect 1ml/kg
per hour after the first 24 hours
• Check biochemical and haematological status
• Maintain adequate pain relief
• Carefully observe wounds, stomas, etc., recording any losses
• Tailor endotracheal suction to each individual’s needs – pre-oxygenating if
necessary
• Encourage parental involvement in care as appropriate
• minimal handling is essential to recovery
• passive movements and change of position every 4 hours – 6- to 8-hourly
care is adequate

51. References
1. WISCONSIN ASSOCIATION for Perinatal Care, Guidelines for the Responsible
Utilization of Neonatal Intensive Care, 1998
2.A Manual of Neonatal Intensive Care , Fifth Edition, Janet M Rennie, Giles S
Kendall, © 2013 CRC Press, Taylor & Francis Group, 6000 Broken Sound Parkway
NW, Suite 300 Boca Raton, FL 33487-2742
3. Admission to the NICU, 2012, Tracey Lawson, Womens Health Maternity Unit,
Ashford and St. Peters Hospital NHS trust
4. Neonatal Intensive Care Nursing, 2nd Edition, Glenys Boxwell, 2010, by
Routledge 2 Park Square, Milton Park, Abingdon, Oxon, OX14 4RN Simultaneously
published in the USA and Canada
5 IAP color atlas of paediatrics, 2012, Publication of Indian Academy of Pediatrics,
Edited by A. Parthasarathy et al, Japee Brothers Medical Publishers(P) Ltd
6. Pediatric Surgery Vol.1, Seventh Edition, 2012, Arnold G. Coran et al, Elsevier
Saunders