Post on 30-Oct-2014
PRINCIPLES OF PRINCIPLES OF NEONATAL SURGERYNEONATAL SURGERY
BY
DR JAMEEL ISMAIL AHMADSURGERY DEPT, AKTH22ND JANUARY, 2008
OUTLINEOUTLINE
INTRODUCTIONINTRODUCTION NEONATAL CONSIDERATIONS NEONATAL CONSIDERATIONS PRE-OPERATIVE CAREPRE-OPERATIVE CARE PEROPERATIVE CAREPEROPERATIVE CARE POSTOPERATIVE CAREPOSTOPERATIVE CARE CURRENT TRENDS CURRENT TRENDS CONCLUSIONCONCLUSION REFERENCESREFERENCES
INTRODUCTIONINTRODUCTION
A neonate is an infant of age 1-28 days Neonates are classified based on
gestational age and birth weight Classification by gestational age
Pre-term- <37 weeks
Term- 37-42 weeks
Post-term- >42 weeks
INTRODUCTIONINTRODUCTION
Classification by birth weight
SGA- <10th percentile
AGA- 10-90th percentile of GA
LGA- >90th percentile of AGA Full term- SGA- <2.5kg
AGA- 2.5-3.5kg
LGA- >3.5kg
INTRODUCTION
Pre-term LBW- 1.5-2kg
VLBW- 1-1.5kg
ELBW- <1kg A normal full term infant has a GA of >37
completed weeks and birth weight of >2.5kg Pre-term is born <37 GA but AGA SGA has birth weight of <10th percentile and
not AGA
INTRODUCTIONINTRODUCTION
Common neonatal surgical conditions GIT-GIT- OA, TOF, Cong. Diaphragmatic hernia, intestinal
atresia, anorectal malformations, Hirschsprung’s disease, Gastroschisis, Omphalocoele, biliary atresia etc
UGSUGS- Hypospadias, Epispadias, Bladder exstrophy, multi/polycystic kidney disease, AEG, undescended testis
CNS-CNS- Hydrocephalus, NTDs MSSMSS- Congenital Hip Dislocation, talipes, sacrococcygeal
teratoma CVS-CVS- Congenital Heart Diseases,COA
ANATOMICAL CONSIDERATIONS OF ANATOMICAL CONSIDERATIONS OF THE NEONATETHE NEONATE
Wider abdomen, broader chest and shallower pelvis
Liver edge is more palpable per abdomen
Urinary bladder is intra abdominal Ribs are horizontal and respiration
almost dependent on diaphragm
PHYSIOLOGICAL NEONATAL PHYSIOLOGICAL NEONATAL CONSIDERATIONSCONSIDERATIONS
A neonate is not a small adult but better considered an immature adult
There many considerations of a surgical neonate which include:
body fluids and electrolytesbody fluids and electrolytes renal functionrenal function cardiovascular functioncardiovascular function respiratory functionrespiratory function thermal controlthermal control Metabolism and nutritionMetabolism and nutrition Immune functionImmune function
BODY FLUID AND ELECTROLYTESBODY FLUID AND ELECTROLYTES
TBW @ birth is 80%, ECF is 45% and ICF is 35% of body weight
In Pre-term it is 84%, 60% and 24% resp The body water is redistributed during the 1st
week through the following phases: pre-diuretic phase- 1st day (1ml/kg/hr) diuretic phase- 2nd-3rd day (7ml/kg/hr) and
natriuresis post-diuretic phase- 4th-5th day
BODY FLUID AND ELECTROLYTESBODY FLUID AND ELECTROLYTES
Fluid administration in early neonatal period should be guided more in Pre-term to prevent overload
Pre-term neonates tolerate fluid restriction more than overload
Sodium regulation is controlled by RAAM which is immature in neonates
Negative Na balance leads to Na retention but in positive Na balance the capacity to excrete Na is poor
RENAL FUNCTIONRENAL FUNCTION 7% of normal neonates may not pass urine in 24hrs Renal handling of water depends on GFR and renal
tubular function GFR is about 25% of adult’s It is function of renal perfusion pressure & renal
vascular resistance which are low and high respectively in the neonate
Tubular urine conc capacity is low with urine osmolality 500-600mosm/kg (cf 1200mosm/kg in adults)
The tubules are relatively insensitive to ADH
CARDIOVASCULAR FUNCTIONCARDIOVASCULAR FUNCTION Fetal circulation undergoes transition to adapt
the extra uterine life Crying and 1st breath leads to lung expansion,
increased O2 tension, decreased pulm artery, increased pulm circulation
Clamping of umbilical cords causes increased systemic artery, LA & LVP which leads to closure of foramen ovale and functional closure of DA
The sphincter closes @ the ductus venosus leading to its closure
BLOOD VOLUMEBLOOD VOLUME
Pre-term- 90ml/kg ~10% body weight Term- 80ml/kg ~7.5% body weight Hb level- 20-22g/dl & haematocrit 60-
65% at birth which decreases as the infant grows
Hb 0f 8g/dl or hct of 30% call for blood transfusion
PULMONARY FUNCTIONPULMONARY FUNCTION
Small and narrow airways- tracheal diameter of 2.5-4mm and can easily be blocked by secretions
Diaphragm is the only muscle of respiration and the sneezing/cough reflexes are absent
Lungs are not fully developed & some alveoli not functional for gas exchange
Tidal volume- 6-10ml/kg and RR up to 60cpm
THERMAL CONTROLTHERMAL CONTROL The mechanism is immature Normal body temp of a neonate is 370c The thermoneutral temp is 32-340c, 28-300c, 30-320c
and 350c for pre-term, term SGA & ELBW neonates respectively
The poor thermal control is due to large BSA/ BW, large BSA/ BW, less subcut fat and thin non-keratinized skin, rich less subcut fat and thin non-keratinized skin, rich surface skin capillaries and poor vasomotor surface skin capillaries and poor vasomotor control, absent sweating & shivering mechanismcontrol, absent sweating & shivering mechanism
Heat loss occur by convection, conduction, evaporation and majorly by radiation
NUTRITION AND METABOLISMNUTRITION AND METABOLISM Small nutritional reserve as main energy source (glucose)
via placenta is cut and then depends on hepatic glycogen store, gluconeogenesis and enteral feeding
All are inadequate in a surgical neonate Total energy requirement in term neonates is
100kcal/kg/day Proteins provide 15% of total calories, carbohydrate & fat
provide 70 and 30% of non-protein calories Prematurity, sepsis, burns increase requirement
NUTRITION AND METABOLISMNUTRITION AND METABOLISM
GLUCOSE Glu control mechanism is immature in neonates and are
predisposed to hypo/ hyperglycaemia Normal blood glucose is 50-60mg/dl (3.33mmol/dl) in
term neonates Hypoglycemia-blood glu <30mg/dl(1.67mmol/dl) in term
and <20mg/dl(<1.1mmol/dl) in LBW may be caused by Low liver glycogen, low gluconeogensis & hyperinsulinism
Prolonged hypoglycaemia leads to seizures & brain damage
Premature neonates, prolonged NPO, diabetic mothers may predispose to hypoglycemia
NUTRITION AND METABOLISMNUTRITION AND METABOLISM
BILURUBIN Physiological jaundice (25-50%) vs. neonatal
jaundice May be due to short RBC life span, immature
hepatic glucoronyl transferase enz or high bilurubin from ABO/ Rh incompatibility, sepsis, G6PD deficiency
Major concern is kernicterus Surgical jaundice- biliary atresia should be
identified to offer early treatment
IMMUNE FUNCTIONIMMUNE FUNCTION
It is immature and are predisposed to infection
Low opsonins: IgA, IgG, IgM, C3b Poor phagocytosis
CONGENITAL ANOMALIESCONGENITAL ANOMALIES neonatal surgery is more or less the surgery of congenital
malformations They are not usually isolated but affect various organ
systems of the body Could be caused by genetic, chromosomal, teratogenic or
unknown causes CNS- Hydrocephalus, NTDs GIT- OA ± TOF, intestinal atresia, ARM, Hirschsprung's
disease Ant abd wall- Omphalocoele, Gastroschisis UGS- PUV, hypo/ epispadias, PKD
PRE-OPERATIVE CAREPRE-OPERATIVE CARE
AIMAIM: to maintain the baby in a physiologically optimal condition for the surgical procedure
RESUSCITATION:- Best done in SCBU Most of our surgical neonates are out born, traveled a long
distance, in bad shape and require resuscitation Ensure good airway by gentle suctioning, O2 & ventilatory
support Fluid,electrolyte & glu mgt-guided and monitored Normal body core temp maintenance NGT for decompression Vital signs monitoring
PRE-OPERATIVE CAREPRE-OPERATIVE CARE
HISTORYHISTORY GA Antenatal Hx- polyhydramnios, maternal
illness, drug hx Family Hx of congenital anomalies Passage of meconium Micturition Bilious vomiting Abdominal distention
PRE-OPERATIVE CAREPRE-OPERATIVE CARE
EXAMINATIONEXAMINATION Gen-colour, cry, activity, temp, hydration,
resp distress, apnoea Features of Prematurity abdominal distension, anal orifice CVS examination Detailed other systemic examination to
detect any anomaly
GENERAL CAREGENERAL CARE
RESPIRATORY SYSTEMRESPIRATORY SYSTEM: Ensure patent airway by gentle sterile suctioning Monitor respiratory rate, rhythm and volume Watch for apnoeic attacks and manage Monitor O2 saturation Humidified O2 in incubator or via O2 hood and not
by face mask or nasal catheter NGT-decompression & to prevent vomiting and
aspiration Pulmonary physiotherapy
GENERAL CAREGENERAL CARE
CARDIOVASCULAR FUNCTIONCARDIOVASCULAR FUNCTION: Fluid loss could occur from vomiting, excessive NGT
aspiration, third space loss and evaporation esp. in anterior abd wall defects and need early replacement
Blood loss may be from birth trauma or haemorrhagic disease
Blood loss should be replaced volume for volume Hb deficit x bw x constant (6,4 & 3 for whole blood,
sedimented or packed cells) Prior to any surgery blood should be grouped and cross
matched
FLUID AND ELECTROLYTESFLUID AND ELECTROLYTES
Fluid and electrolyte derangements usu set in after 24 hours
Mgt is to correct deficit, daily maintenance and replacement of on-going losses and should be strictly according to weight
Fluid requirement first 24hrs- 60-70ml/kg/day 24-48hrs- 70-90ml/kg/day after 48hrs- 100ml/kg/day Na, K and Cl req are 2, 2 & 3 mmols/kg/24hrs
respectively
FLUID AND ELECTROLYTESFLUID AND ELECTROLYTES
50% Ringers lactate(Na-65meq/l and Cl-54meq/l) is the ideal fluid but 4.3% dextrose in 0.18% saline is commonly used
Neonates under radiant heater or phototherapy have higher fluid requirement
Incubators and ventilatory circuits add up to 15-20% of TBW
Monitoring of fluid treatment by input-output chart & vital signs
GENERAL CAREGENERAL CARE
TEMPRETURE REGULATIONTEMPRETURE REGULATION: Surgical neonates should have neutral core body temp and
kept in a thermoneutral environment Overhead radiant heaters provide more access in case of
emergencies than incubatorsNUTRITIONNUTRITION:: most surgical patients are not on enteral feeding and require
parenteral nutrition commonly via peripheral access TPN is the best in some situations but limited by availability and
cost and the neonate need monitoringBILURUBIN BILURUBIN Hyperbilurubinaemia may require phototheraphy or EBT
GENERAL CAREGENERAL CARE
RENAL FUNCTIONRENAL FUNCTION Serial measurement of urine output and kidney
function is essential in monitoring fluid mgt Measurement may not be adequate expect where a
urethral catheter is in situCOAGULATION ABNORMALITIESCOAGULATION ABNORMALITIES May be due to hepatic immaturity, low Vit K or
thrombocytopathy Should be sought and managed Parenteral vitamin K should be given DIC may occur and FPP is given
GENERAL CAREGENERAL CARE
VASCULAR ACCESSVASCULAR ACCESS 24/22G cannular may be used and should be
fixed well to avoid reinsertion Arterial lines may be used for BP monitoring or
blood sampling and CVP lines are for TPN
ANTIBIOTICSANTIBIOTICS Prophylactic or curative and parenteral Empirical Broad spectrum before culture result Group B haemolytic streptococcus and E.coli are the
commonest
GENERAL CAREGENERAL CARE
INVESTIGATIONSINVESTIGATIONS FBC, U/E/Cr, RBS, Ca, bilurubin, GCM ±Blood gasses, PH, Clotting Profile, Blood
culture Caution and care in amount of blood taken to
avoid CV derangement Micro methods reduces the amount taken
PARENTS COUNSELLINGPARENTS COUNSELLING
TRANSPORTTRANSPORT Prenatal diagnosis allowed in-utero transfer of
surgical neonates to tertiary/specialist centers Post-natal transfers are still the commonest here Before transfer the neonate should be optimised
and accompanied by a paediatritian or Nurse trained in ET intubation and ventilator mgt
Detailed reason for referral and parents counseling are essential
The vehicle should be equipped with life support facilities, IVF & drugs
The neonates should be in incubator or wrapped in thick clothing
TRANSPORTTRANSPORT In gastroschisis and ruptured omphalocoele the exposed
viscus are covered by a plastic sheet wrapped with cotton wool
Most of these are not available and the neonates are transported by their parents after visiting several hospitals ± a referral note
The theatre should be proximal to the SCBU Transfer to or from the theatre should also be in an
incubator or with an overhead radiant heater, wrapped & accompanied by a Doctor or Nurse
IVF & NGT should be maintained
PEROPERATIVE CAREPEROPERATIVE CARE
TIMING OF SURGERYTIMING OF SURGERY: Emergency-surgery mandatory due to life threatening
conditions -OA, CD Hernia, intestinal obstruction, leaking MM,
Gastroschisis, Ruptured omphalocoele, ARM Urgent-surgery done as soon as diagnosis is confirmed -cong hydrocephalus, PDA, sacrococcygeal teratoma, CD
hip, inguinal hernia, AEG, Talipes Elective -Biliary atresia, umbilical hernia, undescended testis, Hypo/
Epispadias, PSARP, Pull through
PEROPERATIVE CAREPEROPERATIVE CARE
HYPOTHERMIA PREVENTION & INTRAOP HYPOTHERMIA PREVENTION & INTRAOP MONITORINGMONITORING
Use of thermal mattresses, maintaining a thermoneutral theatre env, radiant heater, warn anaesthetic gasses, IVF, antiseptics and avoiding over wetting during cleaning
Fluid and blood loss monitoring and replacement
Vital signs-HR, BP, Temp, PSO2, ECG ±FBC, U/E/Cr, Blood Gasses, RBS in
prolonged procedures
PEROPERATIVE CAREPEROPERATIVE CARE
ANAESTHESIAANAESTHESIA Neonatal anaesthesia now a recognised subspecialty Pre-op preparation and evaluation Fasting ≥3hrs, vit K, NGT decompression, GCM Premedication- Atropine Anaesthetic equipements -breathing system-light, low resistance & dead space (T-
piece system) -ET tube- appropriate length, diametre & uncuffed -straight blade laryngoscope
PEROPERATIVE CAREPEROPERATIVE CARE
ANAESTHESIAANAESTHESIA Anaesthetic techniques and agents
-induction-inhalational(O2,N2O2, & volatile agent-halothane, isoflurane)
intravenous-thiopentone, ketamine -maintenance-halothane, isoflurane -neuromuscular blockage-suxamethonium, tubocurare -analgesics-narcotics not used, parenteral paracetamol -reversal-stop inhalational(10mins), neostigmine
PEROPERATIVE CAREPEROPERATIVE CARE
OPERATIVE SURGERYOPERATIVE SURGERY Transverse abd incisions preferred Meticulous gentle technique, appropriate instruments
and fine sutures needed Observing general principles of surgery Adequate haemostasis and use of bipolar diathermy Single layer extra mucosal intestinal anastomosis
adequate Stappling devices and endoscopic procedures used Skin closed with single layer absorbable subcuticular
sutures
POSTOPERATIVE CAREPOSTOPERATIVE CARE Neonates recover quicker than adults Monitoring-cont ECG, temp, BP, RR ± blood gasses Analgesia Fluid, electrolyte & input-output chart- maintenance and
replacement Urine output- >1ml/kg/hr suggest good outcome Renal failure managed by kidney challenge or Dialysis Temperature regulation
POSTOPERATIVE CAREPOSTOPERATIVE CARE Identifying and treating hypoglycaemia Hypocalcaemia (<1.5mmol/L) occur in critical neonates in
1st 24-48hrs of life, infant of DM mothers, after large vol transfusion
Post-op haemorrhage- clotting profile, plat to differentiate surgically correctable haemorrhage
Stoma care Long term complications- vit B12 from ileal resection,
incontinence, sexuality, infertility, psychosocial adaptability, malignant potential (undescended testis)
CURRENT TRENDSCURRENT TRENDS
PRENATAL DIAGNOSISPRENATAL DIAGNOSIS USS: in oligo/polyhydramnios, to diagnose abd wall
defects, urinary tract anomalies, intestinal atresia Amniocentesis-USS guided @ 18weeks for karyotyping to
detect inherited/ metab abnormalities Chorionic venous sampling-USS guided @ 8-10weeks for
karyotype,gene probe,enz studies Maternal serum AFP in NTD, duod atresia etc Others: PUBS, MRI Aim: to determine mode of delivery, need for elective
abortion and need for prenatal transfer
CURRENT TRENDSCURRENT TRENDS
FETAL SURGERYFETAL SURGERY 1st open fetal surgery in 1981 @ university of
california Now less invasive procedures eg fetendo and
fetal image guided surgery Procedures include Vesicostomy, CD hernia
closure, excision of sacrococcygeal teratoma, cong heart disease
CONCLUSIONCONCLUSION
Neonatal surgery has developed over the last 4 decades due to better understanding of neonatal physiology and its application to improve surgical outcome
REFERENCESREFERENCES Kulshrestha, R.(2006) Common problems in pediatric
surgery, 2nd edition. CBS publishers and distributors, New Delhi, India
Russell, R.C.G. et al (2004) Bailey & Love’s short practice of Surgery, 24th edition. Edward Arnold Publishers Ltd
Puri, Prem(1996) Newborn Surgery. Butterworth-Heinemann, Oxford
Obianyo, Nene(1996) physiological considerations of the paediatric patient. A lecture
Mohammed A. M. neonatal and paediatric considerations. Undated
Sabiston, D.C. (1997) Sabiston Textbook of Surgery, 15th edition. W.B. Saunders Co. Philadelphia, Pennsylvania