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Neonates present a challenge to the anaesthetist. They have unique physiology as they transition from intrauterine to extrauterine life, limited physiological reserve and immature drug handling. The goals of anaesthesia are to provide stable conditions for surgery, minimise physiological disturbance, reduce pain, and support the neonate during the postoperative period. This article will describe general considerations for anaesthesia in term and preterm neonates, and anaesthesia for some specific neonatal conditions.
Neonates present a challenge to the anaesthetist. They have unique physiology as they transition from intrauterine to extrauterine life, limited physiological reserve and immature drug handling. The goals of anaesthesia are to provide stable conditions for surgery, minimise physiological disturbance, reduce pain, and support the neonate during the postoperative period. This article will describe general considerations for anaesthesia in term and preterm neonates, and anaesthesia for some specific neonatal conditions.


== REOPERATIVE ASSESSMENT OF THE NEONATE ==
== PREOPERATIVE ASSESSMENT OF THE NEONATE ==
As for any child undergoing anaesthesia, it is important to take a detailed history and examination, together with relevant investigations to assess the current physiological status and the impact of any associated congenital abnormalities, which may or may not be related to the surgical condition. This helps to plan when best to proceed with the surgery, and the level of postoperative support required.
As for any child undergoing anaesthesia, it is important to take a detailed history and examination, together with relevant investigations to assess the current physiological status and the impact of any associated congenital abnormalities, which may or may not be related to the surgical condition. This helps to plan when best to proceed with the surgery, and the level of postoperative support required.


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Anorectal malformations (ARM) occur in approximately 1:5000 live births. They represent a wide spectrum of disease, from a simple membrane involving the distal rectum and anus to more complex anomalies involving the genital and urinary tract. Spinal anomalies are frequently found in these patients. These include spinal dysraphism, low lying cord (LLC) and tethered cord.16  Plain spinal Xrays and spinal ultrasound are used to screen for these abnormalities although they may be normal in occult dysraphism. Caudal anaesthesia may be beneficial and can be used in ARM if there is certainty that anomalies of the spine and spinal cord have been excluded.17 ARM may be associated with other anomalies including Vertebral, Anorectal, Cardiac, Tracheoesophageal, Renal and Limb abnormalities, collectively known as the VACTERL association.
Anorectal malformations (ARM) occur in approximately 1:5000 live births. They represent a wide spectrum of disease, from a simple membrane involving the distal rectum and anus to more complex anomalies involving the genital and urinary tract. Spinal anomalies are frequently found in these patients. These include spinal dysraphism, low lying cord (LLC) and tethered cord.16  Plain spinal Xrays and spinal ultrasound are used to screen for these abnormalities although they may be normal in occult dysraphism. Caudal anaesthesia may be beneficial and can be used in ARM if there is certainty that anomalies of the spine and spinal cord have been excluded.17 ARM may be associated with other anomalies including Vertebral, Anorectal, Cardiac, Tracheoesophageal, Renal and Limb abnormalities, collectively known as the VACTERL association.


Primary surgical repair can be undertaken in the neonatal period although more commonly a colostomy is performed and a definitive repair is carried out at a later date. If caudal anaesthesia is contraindicated an opioid-based technique is used (fentanyl 1-2mcg.kg-1 or morphine 20-50mcg.kg-1 [0.02-0.05mg.kg-1], with infiltration with local anaesthetic. Rectal suppositories cannot be used but intravenous paracetamol is a useful adjunct if available. Standard monitoring is usually all that is required. Opioids should be carefully titrated as the usual aim is to extubate at the end of surgery. The patient may be positioned supine or prone depending on the surgical technique. Prone positioning is associated with increased risk to pressure areas, abdominal compression resulting in difficulty with ventilation, endobronchial intubation or tracheal tube displacement. Long-term outcome is variable depending on the complexity of the anorectal malformation. These patients usually require serial anal dilatations following repair.
Primary surgical repair can be undertaken in the neonatal period although more commonly a colostomy is performed and a definitive repair is carried out at a later date.  
 
If caudal anaesthesia is contraindicated an opioid-based technique is used (fentanyl 1-2mcg.kg-1 or morphine 20-50mcg.kg-1 [0.02-0.05mg.kg-1], with infiltration with local anaesthetic. Rectal suppositories cannot be used but intravenous paracetamol is a useful adjunct if available. Standard monitoring is usually all that is required. Opioids should be carefully titrated as the usual aim is to extubate at the end of surgery.
 
The patient may be positioned supine or prone depending on the surgical technique. Prone positioning is associated with increased risk to pressure areas, abdominal compression resulting in difficulty with ventilation, endobronchial intubation or tracheal tube displacement. Long-term outcome is variable depending on the complexity of the anorectal malformation. These patients usually require serial anal dilatations following repair.


=== Intestinal malrotation ===
=== Intestinal malrotation ===
Malrotation occurs in approximately 1:500 live births. Normal intestinal rotation around the superior mesenteric artery (SMA) and fixation during foetal development is interrupted. It may also be associated with congenital diaphragmatic hernia, exomphalos and gastroschisis. Nearly 50% of cases will present in the first week of life most commonly with bilious vomiting secondary to duodenal obstruction.18  This may be due to a midgut volvulus, or physical compression secondary to peritoneal tissue bands or abnormal locations of the duodenum and its surrounding structures. If the condition is diagnosed early the neonate  
Malrotation occurs in approximately 1:500 live births. Normal intestinal rotation around the superior mesenteric artery (SMA) and fixation during foetal development is interrupted. It may also be associated with congenital diaphragmatic hernia, exomphalos and gastroschisis.  
 
Nearly 50% of cases will present in the first week of life most commonly with bilious vomiting secondary to duodenal obstruction.18  This may be due to a midgut volvulus, or physical compression secondary to peritoneal tissue bands or abnormal locations of the duodenum and its surrounding structures. If the condition is diagnosed early the neonate  
may be relatively well with only subtle abdominal signs. The  
may be relatively well with only subtle abdominal signs. The  
neonate may present late with frank sepsis and peritonitis  
neonate may present late with frank sepsis and peritonitis  
secondary to perforated or necrotic bowel. The gold standard radiological investigation is an upper GI contrast series. Plain X-rays are useful if there is concern of another diagnosis or to exclude visceral perforation. These patients require adequate volume resuscitation and electrolyte replacement for ongoing fluid losses and should be taken to theatre as soon as is feasible. A nasogastric tube is inserted to suction the stomach. Prophylactic antibiotics such as co-amoxiclav or benzylpenicllin, gentamicin and metronidazole are required. Ideally invasive monitoring is inserted although it should not delay surgery in the sick neonate. If the gut has been compromised, inotropes may be needed and any coagulopathy will require correction. A central venous line may be required for ongoing total parenteral nutrition in the septic neonate. An opioid based technique can be used although a caudal may be considered if the patient is haemodynamically stable, there are no other contra-indications and extubation is anticipated.  Post-operative NICU care and ventilation is often necessary. Long-term outcomes depend on the extent of the necrotic bowel. Some patients will develop short bowel syndrome and if there is extensive bowel necrosis the mortality is 100%.
secondary to perforated or necrotic bowel. The gold standard radiological investigation is an upper GI contrast series. Plain X-rays are useful if there is concern of another diagnosis or to exclude visceral perforation.
 
These patients require adequate volume resuscitation and electrolyte replacement for ongoing fluid losses and should be taken to theatre as soon as is feasible. A nasogastric tube is inserted to suction the stomach. Prophylactic antibiotics such as co-amoxiclav or benzylpenicllin, gentamicin and metronidazole are required. Ideally invasive monitoring is inserted although it should not delay surgery in the sick neonate. If the gut has been compromised, inotropes may be needed and any coagulopathy will require correction. A central venous line may be required for ongoing total parenteral nutrition in the septic neonate. An opioid based technique can be used although a caudal may be considered if the patient is haemodynamically stable, there are no other contra-indications and extubation is anticipated.  Post-operative NICU care and ventilation is often necessary.  
 
Long-term outcomes depend on the extent of the necrotic bowel. Some patients will develop short bowel syndrome and if there is extensive bowel necrosis the mortality is 100%.


=== Necrotising enterocolitis (NEC) ===
=== Necrotising enterocolitis (NEC) ===
Necrotising enterocolitis occurs in approximately 0.5 – 5:1000 live births. More than 90% of infants diagnosed with NEC are preterm.19  Morbidity and mortality are inversely proportional to the infant’s post-conceptual age (PCA) and birth weight. The aetiology of NEC is multifactorial. Risk factors include vascular compromise of the gastrointestinal tract, commencement of enteral feeding, immature gastrointestinal immunity and sepsis. Hypoxia or ischaemia combined with reduced splanchnic blood flow can occur with patent ductus arteriosus (PDA), cyanotic heart disease, respiratory distress syndrome, shock, asphyxia and with the use of umbilical catheters. NEC may present with subtle gastrointestinal signs including abdominal distension, intolerance of feeds, abdominal tenderness, blood in the stool and bilious vomiting or may present with perforation and peritonitis with systemic signs including shock, temperature instability, acidosis and disseminated intravascular coagulopathy. Supine and decubitus plain Xrays may show the presence of hepatic venous gas, free intraperitoneal air, dilated bowel loops, ascites and asymmetric bowel gas patterns along with pneumatosis intestinalis. Initial management includes discontinuation of enteral feeds, insertion of a nasogastric tube and commencement of broad-spectrum antibiotics such as benzylpenicillin, gentamicin and metronidazole. Ongoing fluid and electrolyte management with parenteral nutrition will be required. Frequent clinical monitoring of systemic and abdominal signs together with radiographic examination, monitoring of laboratory values and acid-base status guides further management. The only absolute indication for surgery is bowel perforation although the decision to proceed to surgery may be made if there is a clinical deterioration. The preoperative assessment should evaluate and optimise any cardiovascular instability, metabolic acidosis, coagulopathy and respiratory compromise. If the patient is too unstable it may be necessary to carry out surgery on the NICU. These patients are often already intubated and ventilated. A high dose fentanyl technique (10-20mcg.kg-1) may be used to promote cardiovascular stability and reduce the systemic stress response.20  Nitrous oxide should be avoided because of the risk of bowel distension. Low cardiac output state, organ hypoperfusion and acidosis secondary to large fluid shifts is common, and large volumes of intravenous fluids are frequently required. Invasive monitoring is useful to guide fluid management and allow frequent arterial blood gas sampling although this must be balanced against the risk of limb ischaemia in the preterm neonate. Insertion of an arterial or a central line should not delay the start of surgery in the sick infant. There is a significant risk of coagulopathy and significant blood loss, and inotropes are often required. Packed red cells should be available and fresh frozen plasma and platelets are often indicated based on laboratory results or clinical evidence of bleeding. Hypothermia and glucose instability are common and should be managed appropriately. Mortality remains significant and long term complications include short bowel syndrome and neurodevelopmental delay.
Necrotising enterocolitis occurs in approximately 0.5 – 5:1000 live births. More than 90% of infants diagnosed with NEC are preterm.19  Morbidity and mortality are inversely proportional to the infant’s post-conceptual age (PCA) and birth weight.  
 
The aetiology of NEC is multifactorial. Risk factors include vascular compromise of the gastrointestinal tract, commencement of enteral feeding, immature gastrointestinal immunity and sepsis. Hypoxia or ischaemia combined with reduced splanchnic blood flow can occur with patent ductus arteriosus (PDA), cyanotic heart disease, respiratory distress syndrome, shock, asphyxia and with the use of umbilical catheters.  
 
NEC may present with subtle gastrointestinal signs including abdominal distension, intolerance of feeds, abdominal tenderness, blood in the stool and bilious vomiting or may present with perforation and peritonitis with systemic signs including shock, temperature instability, acidosis and disseminated intravascular coagulopathy. Supine and decubitus plain Xrays may show the presence of hepatic venous gas, free intraperitoneal air, dilated bowel loops, ascites and asymmetric bowel gas patterns along with pneumatosis intestinalis.  
 
Initial management includes discontinuation of enteral feeds, insertion of a nasogastric tube and commencement of broad-spectrum antibiotics such as benzylpenicillin, gentamicin and metronidazole. Ongoing fluid and electrolyte management with parenteral nutrition will be required. Frequent clinical monitoring of systemic and abdominal signs together with radiographic examination, monitoring of laboratory values and acid-base status guides further management. The only absolute indication for surgery is bowel perforation although the decision to proceed to surgery may be made if there is a clinical deterioration.  
 
The preoperative assessment should evaluate and optimise any cardiovascular instability, metabolic acidosis, coagulopathy and respiratory compromise. If the patient is too unstable it may be necessary to carry out surgery on the NICU.  
 
These patients are often already intubated and ventilated. A high dose fentanyl technique (10-20mcg.kg-1) may be used to promote cardiovascular stability and reduce the systemic stress response.20  Nitrous oxide should be avoided because of the risk of bowel distension. Low cardiac output state, organ hypoperfusion and acidosis secondary to large fluid shifts is common, and large volumes of intravenous fluids are frequently required. Invasive monitoring is useful to guide fluid management and allow frequent arterial blood gas sampling although this must be balanced against the risk of limb ischaemia in the preterm neonate. Insertion of an arterial or a central line should not delay the start of surgery in the sick infant. There is a significant risk of coagulopathy and significant blood loss, and inotropes are often required. Packed red cells should be available and fresh frozen plasma and platelets are often indicated based on laboratory results or clinical evidence of bleeding. Hypothermia and glucose instability are common and should be managed appropriately.  
 
Mortality remains significant and long term complications include short bowel syndrome and neurodevelopmental delay.


=== Oesophageal atresia and tracheoesophageal fistula ===
=== Oesophageal atresia and tracheoesophageal fistula ===
Congenital tracheoesophageal fistula (TOF) occurs in  
Congenital tracheoesophageal fistula (TOF) occurs in  
approximately 1:3,000 live births. It arises during foetal  
approximately 1:3,000 live births. It arises during foetal development as a result of incomplete separation of the oesophagus from the laryngotracheal tube. It is classified based on the site and presence of the fistula and whether there is oesophageal atresia (Figure 2). There may be other associated VACTERL anomalies.
development as a result of incomplete separation of the  
oesophagus from the laryngotracheal tube. It is classified based  
on the site and presence of the fistula and whether there is  
oesophageal atresia (Figure 2). There may be other associated  
VACTERL anomalies.


Neonates with TOF classically present within a few hours of
birth with frothy sputum as they are unable to swallow oral
secretions; delayed diagnosis is associated with episodes of
coughing and choking associated with cyanosis, particularly if
feeding is attempted. There may be copious oral secretions and
abdominal distension due to gastric insufflation via the fistula.
Left untreated the neonate will develop aspiration pneumonia.
The diagnosis of oesophageal atresia is confirmed if it is not
possible to pass a nasogastric tube and the chest Xray will
show the nasogastric tube coiled in the proximal blind-ending


oesophagus (Figure 3). There may be an absent gastric bubble
Figure 2
in isolated oesophageal atresia without a tracheoesophageal
fistula.


The goals of pre-operative management are to stabilise the
child, minimise respiratory embarrassment and assess for
timing of surgery. A nasogastric tube is inserted into the
upper oesophageal pouch to drain secretions. The patient
must be nursed head up or on the side to minimise the risk
of aspiration. Intravenous fluids and prophylactic antibiotics
should be commenced. This allows time for investigations such
as an echocardiogram to exclude other associated congenital
abnormalities.
Our preferred technique is to induce anaesthesia after pre-
oxygenation and to maintain spontaneous ventilation initially
with volatile or intravenous anaesthesia. Prior to repair the
surgeons may perform flexible or rigid bronchoscopy to assess
the level of the fistula and to see if there is a second or proximal
fistula. Take note of the distance measured from the cords
to the fistula to guide tracheal tube placement; the fistula is
mid-tracheal in two thirds of cases, and located at level of the
carina in one third of cases. Muscle relaxants and gentle mask
ventilation may be given prior to intubation. If possible the
tracheal tube is placed distal to the fistula, with the bevel of the
tracheal tube facing anteriorly.
A right thoracotomy is performed with the patient on the
side with a roll under the chest. The tube position must be
checked and effective ventilation confirmed after the change
of position. The lung is then retracted which often results in
difficulty with ventilation, hypercapnoea and acidosis. Periods
of manual ventilation may be required. If gastric distension
occurs prior to ligation of the fistula, the tracheal tube should
be disconnected intermittently to decompress the stomach via
the airway. An arterial line is useful to facilitate arterial blood
gas measurement as end tidal CO
2
measurement is unreliable.
Alternatively, transcutaneous CO
2
monitoring can be used.
Hypercapnoea and acidosis is of particular importance in
the presence of certain cardiac anomalies as the increased
pulmonary vascular resistance can lead to right-to-left shunting
and severe hypoxia. Other pitfalls include ligation of the
wrong structure, intubation of the fistula and endobronchial
intubation.
A balanced anaesthetic should be given, with bolus fentanyl
analgesia as required (1-2mcg.kg
-1
). Blood loss should be
minimal and Ringer’s lactate 10-20ml.kg
-1
is usually all
that is required. The wound should be infiltrated with local
anaesthetic at the end of surgery. Some term infants born in
good condition and with normal preoperative pulmonary
function may be extubated at the end of surgery; most are
likely to require post-operative ventilation and they should be
transferred to a facility able to provide this level of care for
their surgery. Many patients will require serial dilatation of the
oesophagus during infancy.
congenital diaphragmatic hernia
Congenital diaphragmatic hernia (CDH) occurs in
approximately 1:3000 live births. In most cases the aetiology
remains unknown. A defect in the diaphragm, usually on the
left side, results in herniation of midgut structures into the
thoracic cavity. Pulmonary vascular structure and reactivity
are abnormal and there is a varying degree of lung hypoplasia.
Diagnosis is made on antenatal ultrasound or on plain Xray
postnatally when the abnormal bowel loops can be seen within
the thoracic cavity.
Morbidity and mortality is related to the degree of pulmonary
hypertension, right ventricular dysfunction and lung
hypoplasia.
21
A pre-operative echo is performed as a significant
proportion of CDH have associated cardiac anomalies.
Mortality still remains high in patients with significant co-
existing congenital cardiac disease.
22
It is generally accepted
that delaying surgery, usually for 24-48 hours, allows a period
of stabilisation. The reduction in pulmonary artery pressures
and improvement in right ventricular dysfunction may
improve outcome.
There has been a significant improvement in survival over the
past 20 years due to the introduction of ‘gentle ventilation’
strategies.
23
These include permissive hypercapnoea (PaCO
2
<70mmHg), limiting inflation pressures (avoid PIP>25cm
H
2
O and PEEP > 5 cm H
2
O) and accepting relative hypoxaemia


(aim for pre-ductal SpO
Neonates with TOF classically present within a few hours of birth with frothy sputum as they are unable to swallow oral secretions; delayed diagnosis is associated with episodes of coughing and choking associated with cyanosis, particularly if feeding is attempted. There may be copious oral secretions and abdominal distension due to gastric insufflation via the fistula. Left untreated the neonate will develop aspiration pneumonia. The diagnosis of oesophageal atresia is confirmed if it is not possible to pass a nasogastric tube and the chest Xray will show the nasogastric tube coiled in the proximal blind-ending oesophagus (Figure 3). There may be an absent gastric bubble in isolated oesophageal atresia without a tracheoesophageal fistula.
2
 
90-95%). Surgery may need to be  
 
performed whilst the neonate is on high-frequency oscillation  
Figure 3
ventilation or extra-corporeal membrane oxygenation.
 
24
 
Preoperative assessment must pay particular attention to the  
 
presence of significant pulmonary hypertension, ventilation  
The goals of pre-operative management are to stabilise the child, minimise respiratory embarrassment and assess for timing of surgery. A nasogastric tube is inserted into the upper oesophageal pouch to drain secretions. The patient
requirements, and associated cardiac anomalies. If the infant  
must be nursed head up or on the side to minimise the risk of aspiration. Intravenous fluids and prophylactic antibiotics should be commenced. This allows time for investigations such as an echocardiogram to exclude other associated congenital abnormalities.
is not already intubated, anaesthesia is induced with care to  
 
avoid gastric insufflation with bag valve mask ventilation and  
Our preferred technique is to induce anaesthesia after pre-oxygenation and to maintain spontaneous ventilation initially with volatile or intravenous anaesthesia. Prior to repair the surgeons may perform flexible or rigid bronchoscopy to assess the level of the fistula and to see if there is a second or proximal fistula. Take note of the distance measured from the cords to the fistula to guide tracheal tube placement; the fistula is mid-tracheal in two thirds of cases, and located at level of the carina in one third of cases. Muscle relaxants and gentle mask ventilation may be given prior to intubation. If possible the tracheal tube is placed distal to the fistula, with the bevel of the tracheal tube facing anteriorly.
further lung compression. A nasogastric tube is inserted to  
 
decompress the stomach. Invasive monitoring is required to  
A right thoracotomy is performed with the patient on the side with a roll under the chest. The tube position must be checked and effective ventilation confirmed after the change of position. The lung is then retracted which often results in difficulty with ventilation, hypercapnoea and acidosis. Periods of manual ventilation may be required. If gastric distension occurs prior to ligation of the fistula, the tracheal tube should be disconnected intermittently to decompress the stomach via the airway. An arterial line is useful to facilitate arterial blood gas measurement as end tidal CO2 measurement is unreliable. Alternatively, transcutaneous CO2 monitoring can be used. Hypercapnoea and acidosis is of particular importance in the presence of certain cardiac anomalies as the increased pulmonary vascular resistance can lead to right-to-left shunting and severe hypoxia. Other pitfalls include ligation of the wrong structure, intubation of the fistula and endobronchial intubation.
allow serial blood gas measurement. There is a risk of blood loss  
 
and a unit of packed red cells should be available. In patients  
A balanced anaesthetic should be given, with bolus fentanyl analgesia as required (1-2mcg.kg-1). Blood loss should be
with significant pulmonary hypertension, having nitric oxide  
minimal and Ringer’s lactate 10-20ml.kg-1 is usually all that is required. The wound should be infiltrated with local anaesthetic at the end of surgery. Some term infants born in good condition and with normal preoperative pulmonary function may be extubated at the end of surgery; most are likely to require post-operative ventilation and they should be transferred to a facility able to provide this level of care for their surgery. Many patients will require serial dilatation of the oesophagus during infancy.
available in theatre may be critical for treatment of pulmonary  
 
hypertensive crises.
=== Congenital diaphragmatic hernia ===
A subcostal or transverse abdominal incision is made and  
Congenital diaphragmatic hernia (CDH) occurs in approximately 1:3000 live births. In most cases the aetiology remains unknown. A defect in the diaphragm, usually on the left side, results in herniation of midgut structures into the thoracic cavity. Pulmonary vascular structure and reactivity are abnormal and there is a varying degree of lung hypoplasia. Diagnosis is made on antenatal ultrasound or on plain Xray postnatally when the abnormal bowel loops can be seen within the thoracic cavity.
the herniated viscera are reduced into the abdomen. The  
 
diaphragmatic defect is then either closed primarily or with  
Morbidity and mortality is related to the degree of pulmonary hypertension, right ventricular dysfunction and lung hypoplasia.21  A pre-operative echo is performed as a significant proportion of CDH have associated cardiac anomalies. Mortality still remains high in patients with significant co-existing congenital cardiac disease.22  It is generally accepted that delaying surgery, usually for 24-48 hours, allows a period of stabilisation. The reduction in pulmonary artery pressures and improvement in right ventricular dysfunction may improve outcome.
a prosthetic patch if the defect is large. Thoracoscopic repair  
 
is being undertaken in some centres. Following abdominal  
There has been a significant improvement in survival over the past 20 years due to the introduction of ‘gentle ventilation’ strategies.23  These include permissive hypercapnoea (PaCO2 <70mmHg), limiting inflation pressures (avoid PIP>25cm H2O and PEEP > 5 cm H2O) and accepting relative hypoxaemia
closure, raised intra-abdominal pressures may lead to  
 
difficulty with ventilation and a risk of developing abdominal  
(aim for pre-ductal SpO2 90-95%). Surgery may need to be performed whilst the neonate is on high-frequency oscillation ventilation or extra-corporeal membrane oxygenation.24
compartment syndrome, and delayed closure may be necessary.  
 
Lung compliance decreases post-operatively and post-operative  
Preoperative assessment must pay particular attention to the presence of significant pulmonary hypertension, ventilation requirements, and associated cardiac anomalies. If the infant is not already intubated, anaesthesia is induced with care to avoid gastric insufflation with bag valve mask ventilation and further lung compression. A nasogastric tube is inserted to decompress the stomach. Invasive monitoring is required to allow serial blood gas measurement. There is a risk of blood loss and a unit of packed red cells should be available. In patients with significant pulmonary hypertension, having nitric oxide available in theatre may be critical for treatment of pulmonary hypertensive crises.  
ventilation is usually necessary. These patients often suffer from  
 
chronic respiratory disease, gastro-oesophageal reflux disease  
A subcostal or transverse abdominal incision is made and the herniated viscera are reduced into the abdomen. The diaphragmatic defect is then either closed primarily or with a prosthetic patch if the defect is large. Thoracoscopic repair is being undertaken in some centres. Following abdominal closure, raised intra-abdominal pressures may lead to difficulty with ventilation and a risk of developing abdominal compartment syndrome, and delayed closure may be necessary. Lung compliance decreases post-operatively and post-operative ventilation is usually necessary. These patients often suffer from chronic respiratory disease, gastro-oesophageal reflux disease and neurodevelopmental delay.
and neurodevelopmental delay.
 
=== Gastroschisis and exomphalos (omphalocele) ===
Gastroschisis and exomphalos are both ventral wall defects resulting in herniation of abdominal viscera. Diagnosis is ideally made on antenatal ultrasound scan.
 
Gastroschisis occurs in approximately 1:3000 live births. The herniated viscera are not covered by a sac. It is thought to occur secondary to an ischaemic insult during abdominal wall development or due to early rupture of the hernia of the umbilical cord. A relatively small percentage (10-20%) are associated with other congenital abnormalities and these predominantly involve the gastrointestinal tract.25
 
Exomphalos occurs in approximately 1:5000 live births. Failure of normal embryological development results in the bowel remaining within the umbilical cord and not returning to the abdomen. The herniated viscera is covered by a sac. There is a high incidence of associated congenital abnormalities including cardiac anomalies. Specific chromosomal associations include trisomies 13, 15, 18 and 21 and it can be associated with Beckwith-Wiedemann syndrome.
 
To avoid bowel injury the baby is delivered by caesarean section. The operating theatre should be warmed, the baby dried, any exposed bowel covered with plastic and a nasogastric tube is inserted to decompress the stomach. Fluid resuscitation is commenced, a urinary catheter inserted and broad spectrum antibiotics started. Co-existing congenital abnormalities, especially cardiac, should be assessed. A renal or cranial ultrasound may also be indicated.
 
Surgery is more urgent in gastroschisis due to the ongoing fluid losses and electrolyte and metabolic derangement. If primary closure is not possible then a ‘silo’ is placed over the exposed bowel, which may require a general anaesthetic if the defect needs extending to fit the device. The silo is suspended above the patient postoperatively, and the bowel is gradually reduced into the abdominal cavity under gravity over the ensuing few days in the NICU. When the patient is stable and spontaneous reduction of the bowel has reached a plateau, then surgery for reduction and closure of hernia is performed. Surgery for exomphalos is less urgent, unless the sac has ruptured. If the patient is stable and the defect is small a primary repair can usually be done. In large defects, if the sac has not ruptured, it may be treated with topical silver sulfadizine to allow epithelisation with definitive surgery at a later stage.
 
The neonate will require intubation and ventilation for surgery. Expect significant ongoing fluid and heat losses due to the exposed viscera. Peripheral intravenous access may be all that is required, but central venous pressure monitoring and an arterial line are useful to help guide fluid administration. Avoid the femoral vessels as there is a risk of decreased perfusion with the increased abdominal pressures. Placing the post-ductal oxygen saturation probe on either lower limb helps to give an indication if there is poor perfusion. Muscle relaxants will assist the surgeons in reducing the abdominal contents. Reduction of the bowel may cause abdominal compartment syndrome, diaphragmatic splinting and high ventilation pressures. If the intra gastric pressures are >20mmHg or the peak inspiratory pressures exceed 30cm H2O then a staged repair is indicated.26
 
Unless there is a very small defect the infant will require post- operative ventilation and a generous opioid-based anaesthetic technique can be used (fentanyl 10-20mcg.kg-1). These patients often require parenteral nutrition and a significant proportion present for further abdominal surgery.
 
== CONCLUSION ==
Improving outcomes in neonatal anaesthesia is dependent on a thorough understanding of the unique anaesthetic requirements of the neonate and a detailed knowledge of the different pathologies that present during this period. Unnecessary surgery should be avoided during the neonatal period as anaesthesia and surgical stress may have detrimental effects on the very immature child.
 
== REFERENCES ==
1.Anand KJ, Aynsley-Green A. Measuring the severity of surgical stress in newborn infants. J Pediatr Surg 1988; 23 297-305.
2.Anand KJ. Clinical importance of pain and stress in preterm neonates. Biol Neonate 1998; 73 1-9.
 
3.Taddio A, Katz J, Ilersich AL, Koren G. Effect of neonatal circumcision on pain response during subsequent routine vaccination. Lancet 1997; 349 599-603.


Gastroschisis and exomphalos (omphalocele)
4.Stevens B, Yamada J, Lee GY, Ohlsson A. Sucrose for analgesia in newborn infants undergoing painful procedures. Cochrane Database Syst Rev 2013 1:CD001069.
Gastroschisis and exomphalos are both ventral wall defects
resulting in herniation of abdominal viscera. Diagnosis is
ideally made on antenatal ultrasound scan.
Gastroschisis occurs in approximately 1:3000 live births. The
herniated viscera are not covered by a sac. It is thought to
occur secondary to an ischaemic insult during abdominal
wall development or due to early rupture of the hernia of
the umbilical cord. A relatively small percentage (10-20%)
are associated with other congenital abnormalities and these
predominantly involve the gastrointestinal tract.
25
Exomphalos occurs in approximately 1:5000 live births. Failure
of normal embryological development results in the bowel
remaining within the umbilical cord and not returning to the
abdomen. The herniated viscera is covered by a sac. There is a
high incidence of associated congenital abnormalities including
cardiac anomalies. Specific chromosomal associations include
trisomies 13, 15, 18 and 21 and it can be associated with
Beckwith-Wiedemann syndrome.
To avoid bowel injury the baby is delivered by caesarean
section. The operating theatre should be warmed, the baby
dried, any exposed bowel covered with plastic and a nasogastric
tube is inserted to decompress the stomach. Fluid resuscitation
is commenced, a urinary catheter inserted and broad spectrum
antibiotics started. Co-existing congenital abnormalities,
especially cardiac, should be assessed. A renal or cranial
ultrasound may also be indicated.
Surgery is more urgent in gastroschisis due to the ongoing fluid
losses and electrolyte and metabolic derangement. If primary
closure is not possible then a ‘silo’ is placed over the exposed
bowel, which may require a general anaesthetic if the defect
needs extending to fit the device. The silo is suspended above
the patient postoperatively, and the bowel is gradually reduced
into the abdominal cavity under gravity over the ensuing few
days in the NICU. When the patient is stable and spontaneous
reduction of the bowel has reached a plateau, then surgery
for reduction and closure of hernia is performed. Surgery for  
exomphalos is less urgent, unless the sac has ruptured. If the
patient is stable and the defect is small a primary repair can
usually be done. In large defects, if the sac has not ruptured,
it may be treated with topical silver sulfadizine to allow
epithelisation with definitive surgery at a later stage.
The neonate will require intubation and ventilation for surgery.
Expect significant ongoing fluid and heat losses due to the
exposed viscera. Peripheral intravenous access may be all that
is required, but central venous pressure monitoring and an
arterial line are useful to help guide fluid administration. Avoid
the femoral vessels as there is a risk of decreased perfusion with
the increased abdominal pressures. Placing the post-ductal
oxygen saturation probe on either lower limb helps to give an
indication if there is poor perfusion. Muscle relaxants will assist
the surgeons in reducing the abdominal contents. Reduction
of the bowel may cause abdominal compartment syndrome,
diaphragmatic splinting and high ventilation pressures. If the
intra gastric pressures are >20mmHg or the peak inspiratory
pressures exceed 30cm H
2
O then a staged repair is indicated.
26
Unless there is a very small defect the infant will require post-
operative ventilation and a generous opioid-based anaesthetic
technique can be used (fentanyl 10-20mcg.kg
-1
). These patients
often require parenteral nutrition and a significant proportion
present for further abdominal surgery.
conclUSion
Improving outcomes in neonatal anaesthesia is dependent
on a thorough understanding of the unique anaesthetic
requirements of the neonate and a detailed knowledge of
the different pathologies that present during this period.
Unnecessary surgery should be avoided during the neonatal
period as anaesthesia and surgical stress may have detrimental
effects on the very immature child.


5.Shah PS, Herbozo C, Aliwalas LL, Shah VS. Breastfeeding or breast milk for procedural pain in neonates. Cochrane Database Syst Rev 2012 12:CD004950.


reFerenceS
6.Cerbo RM, Maragliano R, Pozzi M, Strocchio L. Global perfusion assessment and tissue oxygen saturation in preterm infants: where are we? Early Hum Dev 2013; 89
1.
Anand KJ, Aynsley-Green A. Measuring the severity of surgical
stress in newborn infants.
J Pediatr Surg
1988;
23
: 297-305.
2.
Anand KJ. Clinical importance of pain and stress in preterm
neonates.
Biol Neonate
1998;
73
: 1-9.
3.
Taddio A, Katz J, Ilersich AL, Koren G. Effect of neonatal
circumcision on pain response during subsequent routine
vaccination.
Lancet
1997;
349
: 599-603.
4.
Stevens B, Yamada J, Lee GY, Ohlsson A. Sucrose for analgesia
in newborn infants undergoing painful procedures. Cochrane
Database Syst Rev 2013 1:CD001069.
5.
Shah PS, Herbozo C, Aliwalas LL, Shah VS. Breastfeeding or
breast milk for procedural pain in neonates. Cochrane Database
Syst Rev 2012 12:CD004950.
6.
Cerbo RM, Maragliano R, Pozzi M, Strocchio L. Global perfusion  
assessment and tissue oxygen saturation in preterm infants:  
where are we?  
Early Hum Dev
2013;  
89
(S1): S44-6.
(S1): S44-6.
7.
 
Bancalari E, Claure N. Oxygenation targets and outcomes in  
7.Bancalari E, Claure N. Oxygenation targets and outcomes in premature infants. JAMA 2013; 117 2161-2.
premature infants.  
 
JAMA
8.Stenson B, Brocklehurst P, Tarnow-Mordi W. U.K. BOOST II trial; Australian BOOST II trial; New Zealand BOOST II trial. Increased 36-week survival with high oxygen saturation target in extremely preterm infants. N Engl J Med 2011; 364 1680- 82.
2013;  
 
117
9.Schmidt B, Whyte RK, Asztalos EV et al. Canadian Oxygen Trial (COT) Group. Effects of targeting higher vs lower arterial oxygen saturations on death or disability in extremely preterm infants: a randomized clinical trial. JAMA 2013; 309 2111-20.
: 2161-2.
 
8.
10.Cote CJ Postoperative apnea in former preterm infants after inguinal herniorrhaphy: A combined analysis. Anesthesiology 1995; 82 809-22.
Stenson B, Brocklehurst P, Tarnow-Mordi W. U.K. BOOST II trial;  
 
Australian BOOST II trial; New Zealand BOOST II trial. Increased  
11.Henderson-Smart DJ, Steer P. Prophylactic caffeine to prevent postoperative apnea following general anesthesia in preterm infants. Cochrane Database Syst Rev 2001;4:CD000048.
36-week survival with high oxygen saturation target in  
 
extremely preterm infants.  
12.Kao LS, Morris BH, Lally KP, Stewart CD, Huseby V, Kennedy KA. Hyperglycemia and morbidity and mortality in extremely low birth weight infants. J Perinatol 2006; 26 730-6.
N Engl J Med
 
2011;  
13.Olsen EA, Brambrink AM. Anesthetic neurotoxicity in the newborn and infant. Curr Opin Anaesthesiol 2013 August 29 (e-pub ahead of print).page 132
364
 
; 1680-
14.Malviya S, Swartz J, Lerman J. Are all preterm infants younger than 60 weeks postconceptional age a risk for post-anesthetic apnea? Anesthesiology 1993; 78 1076–81.
82.
 
9.
15.Craven PD, Badawi N, Henderson-Smart DJ, O’Brien M. Regional (spinal, epidural, caudal) versus general anaesthesia in preterm infants undergoing inguinal herniorrhaphy in early infancy. Cochrane Database Syst Rev 2003;3:CD003669.
Schmidt B, Whyte RK, Asztalos EV et al. Canadian Oxygen Trial  
 
(COT) Group. Effects of targeting higher vs lower arterial  
16.Teo AT, Gan BK, Tung JS, Low Y, Seow WT. Low-lying spinal cord and tethered cord syndrome in children with anorectal malformations. Singapore Med J 2012; 53 570-6.
oxygen saturations on death or disability in extremely preterm  
 
infants: a randomized clinical trial.  
17.Bozza P, Morini F, Conforti A, Sgrò S. Stress and ano-colorectal  
JAMA
surgery in newborn/infant: role of anesthesia. Pediatr Surg Int 2012; 28 821-4.
2013;  
 
309
18.Millar AJ, Rode H, Cywes S. Malrotation and volvulus in infancy and childhood. Semin Pediatr Surg 2003; 12 229-36.
: 2111-20.
 
10.
19.Llanos AR, Moss ME, Pinzòn MC, Dye T. Epidemiology of neonatal necrotizing enterocolitis: a population-based study. Paediatr Perinat Epidemiol 2002; 16 342-9.
Cote CJ Postoperative apnea in former preterm infants after  
 
inguinal herniorrhaphy: A combined analysis.  
20.Anand KJ, Sippell WG, Aynsley-Green A. Randomised trial of fentanyl anaesthesia in preterm babies undergoing surgery: effects on the stress response. Lancet 1987; 1 62–6 [published
Anesthesiology  
 
1995;  
correction appears in Lancet 1987; 1 234].
82
 
: 809-22.
21.Wynn J, Krishnan U, Aspelund G, Zhang Y et al. Outcomes of congenital diaphragmatic hernia in the modern era of management. J Pediatr 2013; 163 114-9 e1.
11.
 
Henderson-Smart DJ, Steer P. Prophylactic caffeine to prevent  
22.Graziano JN. Cardiac anomalies in patients with congenital diaphragmatic hernia and their prognosis: a report from the Congenital Diaphragmatic Hernia Study Group. J Pediatr Surg  
postoperative apnea following general anesthesia in preterm  
infants. Cochrane Database Syst Rev 2001;4:CD000048.
12.
Kao LS, Morris BH, Lally KP, Stewart CD, Huseby V, Kennedy  
KA. Hyperglycemia and morbidity and mortality in extremely  
low birth weight infants.  
J Perinatol
2006;  
26
: 730-6.
13.
Olsen EA, Brambrink AM. Anesthetic neurotoxicity in the  
newborn and infant.  
Curr Opin Anaesthesiol
2013 August 29  
(e-pub ahead of print).
page 132
14.
Malviya S, Swartz J, Lerman J. Are all preterm infants younger  
than 60 weeks postconceptional age a risk for post-anesthetic  
apnea?  
Anesthesiology
1993;  
78
: 1076–81.
15.
Craven PD, Badawi N, Henderson-Smart DJ, O’Brien M. Regional  
(spinal, epidural, caudal) versus general anaesthesia in preterm  
infants undergoing inguinal herniorrhaphy in early infancy.  
Cochrane Database Syst Rev 2003;3:CD003669.
16.
Teo AT, Gan BK, Tung JS, Low Y, Seow WT. Low-lying spinal  
cord and tethered cord syndrome in children with anorectal  
malformations.  
Singapore Med J
2012;  
53
: 570-6.
17.
Bozza P, Morini F, Conforti A, Sgrò S. Stress and ano-colorectal  
surgery in newborn/infant: role of anesthesia.  
Pediatr Surg Int  
2012;  
28
: 821-4.
18.
Millar AJ, Rode H, Cywes S. Malrotation and volvulus in infancy  
and childhood.  
Semin Pediatr Surg
2003;  
12
: 229-36.
19.
Llanos AR, Moss ME, Pinzòn MC, Dye T. Epidemiology of  
neonatal necrotizing enterocolitis: a population-based study.  
Paediatr Perinat Epidemiol
2002;  
16
: 342-9.
20.
Anand KJ, Sippell WG, Aynsley-Green A. Randomised trial of  
fentanyl anaesthesia in preterm babies undergoing surgery:  
effects on the stress response.  
Lancet
1987;  
1
: 62–6 [published  
correction appears in  
Lancet
1987;  
1
: 234].
21.
Wynn J, Krishnan U, Aspelund G, Zhang Y et al. Outcomes  
of congenital diaphragmatic hernia in the modern era of  
management.  
J Pediatr
2013;  
163
: 114-9 e1.
22.
Graziano JN. Cardiac anomalies in patients with congenital  
diaphragmatic hernia and their prognosis: a report from the  
Congenital Diaphragmatic Hernia Study Group.  
J Pediatr Surg  
2005;  
2005;  
40
40 1045-9
: 1045-9
 
23.
23.Guidry CA, Hranjec T, Rodgers BM, Kane B. Permissive hypercapnia in the management of congenital diaphragmatic hernia: our institutional experience. J Am Coll Surg 2012; 214 640-645.
Guidry CA, Hranjec T, Rodgers BM, Kane B. Permissive  
 
hypercapnia in the management of congenital diaphragmatic  
24.Fallon SC, Cass DL, Olutoye OO, Zamora IJ et al. Repair of  
hernia: our institutional experience.  
congenital diaphragmatic hernias on Extracorporeal Membrane Oxygenation (ECMO): Does early repair improve patient survival? J Pediatr Surg 2013; 48 1172-6.
J Am Coll Surg
 
25.Molik KA, Gingalewski CA, West KW et al. Gastroschisis: a plea for risk categorization. J Pediatr Surg 2001; 36 51–5.
2012;  
 
214
26.Yaster M, Scherer TL, Stone MM et al. Prediction of successful primary closure of congenital abdominal wall defects using intraoperative measurements. J Pediatr Surg 1989; 24 1217–20.
: 640-645.
24.
Fallon SC, Cass DL, Olutoye OO, Zamora IJ et al. Repair of  
congenital diaphragmatic hernias on Extracorporeal Membrane  
Oxygenation (ECMO): Does early repair improve patient  
survival?  
J Pediatr Surg
2013;  
48
: 1172-6.
25.
Molik KA, Gingalewski CA, West KW et al. Gastroschisis: a plea  
for risk categorization.  
J Pediatr Surg
2001;  
36
: 51–5.
26.
Yaster M, Scherer TL, Stone MM et al. Prediction of successful  
primary closure of congenital abdominal wall defects using  
intraoperative measurements.  
J Pediatr Surg
1989;  
24
: 1217–20.
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