Manual of Perioperative Care (Woodhead/Manual of Perioperative Care) || Neonatal Surgery

Section 4Different Patient

Care Groups

Chapter 25 Neonatal Surgery Helen Carter

Chapter 26 Paediatric Surgery Helen Carter

Chapter 27 Care of the Adolescent in Surgery Liz McArthur

Chapter 28 Care of the Elderly Patient Rita Hehir

Chapter 29 Bariatric Surgery Saheba Iaciofano

Chapter 30 Perioperative Care of the Pregnant Woman Adrienne Montgomery

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Manual of Perioperative Care: An Essential Guide, First Edition. Edited by Kate Woodhead and Lesley Fudge.© 2012 John Wiley & Sons, Ltd. Published 2012 by John Wiley & Sons, Ltd.

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Neonatal Surgery Helen Carter

Neonatal surgery covers the preterm infant to the first month of post normal gesta-tional life. In practice this means from 24 weeks gestation to 44 weeks gestation and beyond. The extreme preterm infant requiring surgery may weigh between 500 g and 1 kg, less than a bag of sugar. Many neonates who have not been home post birth will remain on the neonatal surgical unit until they gain enough weight, generally reaching 3–3.5 kg depending on local protocols/guidelines, before being cared for on the conven-tional paediatric ward. Neonatal surgery is conducted in supraregional centres by expe-rienced paediatric surgeons with specially trained, highly skilled staff with excellent support from other services, such as knowledgeable nurses, paediatric theatre practi-tioners, neonatologists, paediatric radiologists, physiotherapists, microbiologists, occu-pational therapists, pharmacists and dieticians, to name but a few.

Most centres use a retrieval service to safely transport neonates requiring surgery from hospitals which do not have these services. As many neonates require surgery within the first few days of birth, the mother may not be in the same hospital. This raises issues about consent for surgery, which sometimes this has to be done over the phone. This is not ideal. Many congenital deformities can be identified during preg-nancy. In this case the parents will have had counselling from their obstetrician and a paediatric surgeon so they have some idea of what to expect. It is a stressful and emo-tional time for the family when a baby is born, but when they have surgery to cope with as well it becomes even more difficult. This is all happening when a mother should be bonding with her baby, but we may be starving the infant for surgery, and parents often worry about touching their newborn child following surgery in case they hurt them. It is a time where the parents need a lot of support and understanding.

To many theatre practitioners, involvement in neonatal surgery is a daunting pros-pect. The difference from adult practice is vast, from the obvious contrast in size to the wide variety of surgical procedures the practitioner needs to become familiar with. The bulk of work in the adult field involves surgery to repair the body from the effects of disease or trauma, whereas in the neonate most surgery is carried out to repair con-genital deformities due to interruption of normal embryological development or to correct the complications due to prematurity. Table 25.1 shows the incidence of a num-ber of congenital abnormalities. The neonate may go on to need further surgery into

CHAPTER 25

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256 Different Patient Care Groups

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childhood and on into adulthood. A good knowledge of normal anatomy is required in order to be able to understand the altered anatomy caused by congenital abnormalities.

Because of the size of these patients the environment and equipment in the operating room needs careful consideration. Neonates do not have the same physiological ability to regulate their temperature as the adult or older child. Fluid maintenance during sur-gery differs, as does method of administration. Haemoglobin in the neonate changes from fetal to adult. Medication requirements differ because of the immature hepatic enzyme system and reduced renal function following birth, which can drastically increase the half-life of some medications. Appropriate instrumentation should be selected due to the nature of the tissues and the scale of the operative site. Magnification in the form of surgical ‘loupes’ or microscopes may be necessary. Consideration is needed of the draping materials because of their weight, method of keeping in place and material (i.e. disposable versus reusable). Disposable drapes are generally lighter but usually have an adhesive edge to adhere the drape to the patient, which may remove the delicate skin of the newborn patient.

Neonatal surgery is complicated not just because of the wide range of abnormalities but also the need for prudent planning for each individual patient from transfer from the ward, through induction of anaesthesia, operation and how the neonate is trans-ferred back to the ward and which ward area is appropriate. Decisions as to whether they require neonatal intensive care or the surgical neonatal ward post surgery will need to be taken. Communication between the theatre practitioners, the ward nurses and neonatologists, the anaesthetist and the operating surgeon are key to ensuring a safe, effective procedure with no delays to the surgery, which may affect the overall outcome for the patient.

Blood loss/Haemostasis and Fluid Requirements

A newborn baby’s body comprises 75% water at term (Bhatia 2006 ), more if preterm, and reduces to 60% by adulthood. In the neonate most of this water is extracellular fluid (ECF), so they do not cope well with fluid loss. In the premature neonate the ratio of ECF to intracellular fluid (ICF) is even higher. In the adult patient ICF is higher than ECF. Electrolyte imbalance during the neonatal period can be a significant problem and should be monitored perioperatively by use of blood gases. This helps the anaesthetist to calculate intravenous (IV) fluid amount and type required.

Neonatal blood volume is around 80 mL/kg so a term baby weighing 3 kg will only have a circulating volume of 240 mL. Prior to surgery, vitamin K should be given.

Table 25.1 Incidence of congenital abnormalities per live births (approx).

Congenital heart defect 1 : 125

Hypospadias 1 : 300

Talipes 1 : 1000

Congenital diaphragmatic hernia 1 : 2500

Gastroschisis 1 : 2000

Tracheoesophageal fistula/oesophageal atresia 1 : 3500

Anorectal malformations 1 : 5000

Duodenal atresia 1 : 7500

Biliary atresia 1 : 15 000


Neonatal Surgery 257

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Vitamin K is necessary for the production of prothrombin, a crucial part of the normal clotting cascade. Preoperative bloods should be taken for full blood count, urea and electrolytes. The infant requires a maternal cross-matched blood sample up to the age of four months (there are exceptions to this, e.g. unusual maternal antibodies). This is because the neonate’s haemoglobin is composed of fetal haemoglobin, which has a different oxygen-holding capacity, and there is a gradual change to adult haemoglobin over the first four months of life. General principles for the requirement for transfusion are the same as for adults (i.e. ≥15% of blood volume lost). Therefore a term neonate weighing 3 kg may require transfusion following a loss of only 36 mL during surgery. When dealing with such small volumes it becomes imperative to keep a note of blood loss on swabs through weighing (blood has a similar specific gravity to water, therefore 1 g = 1 mL) and through suctioning, recorded and communicated to the anaesthetist. Syringe drivers can be used for blood transfusion in neonates as long as a 170–200 μm filter is incorporated into the infusion (McClelland 2007 ). Small Paedipaks containing 40 mL can be obtained.

The need for careful haemostasis is paramount when operating on the neonate. This means gentle tissue handling, acting quickly to stop bleeding and the use of precise diathermy to coagulate even minimal bleeding points. Bipolar diathermy is widely used in neonatal surgery due to the accurate nature of the application and lack of thermal spread found with monopolar diathermy. When dealing with such small, closely located structures this prevents unwanted tissue damage.

Airway Management

Neonates breathe mainly through the nose. This should be remembered when position-ing a mask and care should be taken not to apply too much pressure which can obstruct the nasal passages. The larynx is higher and more anterior in the neonate than in the older child and adult. The epiglottis is more floppy and elongated. These differences can make the neonate more difficult to intubate. The narrowest part of the upper airway is at the cricoid ring compared to the larynx in the post-pubertal child and adult. The cricoid ring forms a natural cuff, and for this reason uncuffed endotracheal (ET) tubes are used. These allow an air leak that prevents mucosal oedema which could block a small airway. In the neonate requiring prolonged ventilation, this could lead to subglottic stenosis.

Use of the correct size of ET tube is essential to prevent damage. The ET tube size formula (age in years/4 + 4) does not work for the infant under 1 year. As a guide, for the neonate use the following internal diameter (ID) tubes:

� < 1000 g: 2.5 mm ID � 1000–2000 g: 3.0 mm ID � 2000–3000 g: 3.5 mm ID � > 3000 g: 3.5–4.0 mm ID.

A tube size down and up from the one anticipated should be prepared. Neonatal laryn-goscopes have a straight blade but not all anaesthetists like this pattern. For oral intuba-tion some anaesthetists prefer the tube to have a stilette inserted. If required it should be ensured the stilette is 1 cm inside the distal end of the ET tube to prevent damage on insertion.

Prior to intubation and postoperatively, to keep the airway open the neonate’s head should be placed in a neutral position, preventing their relatively large head flexing on their comparatively short neck and avoiding blockage of the airway. If the tongue is occluding the airway a chin lift may also be necessary. Newborn babies will be observed



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overnight following surgery up to 52 weeks gestational age, or 60 weeks for premature babies, because they are prone to apnoea post anaesthetic due to immature respiratory control.

Temperature Regulation

Neonatal and premature infants have a large surface area to body mass ratio compared to adults. This means that they are more inclined to lose heat by evaporation, convec-tion, radiation and conduction than older children or adults. Healthy term neonates maintain their temperature by peripheral vasoconstriction in response to their sur-roundings, but in premature babies this response is poorly developed. Anaesthesia also dulls this response. Neonates are unable to shiver, a mechanism used by older children and adults to trap air beneath body hair to retain a warm air layer next to the skin. They also have very thin skin and little insulating fat. During induction of anaesthesia the neonate is often exposed for intubation, IV access and pain-controlling blocks. In order to minimise heat loss during this time the use of an overhead heater, heated mat-tresses, warm ambient room temperature and increased humidity can help.

During surgery it is not usually possible for the surgeon to operate under an overhead heater, therefore other heating adjuncts should be used such as Bair Huggers™, heated mattresses, plastic sheeting covering the non-operative site, baby bonnet, warmed prep-ping and washing solutions and a warm ambient theatre temperature. Care should be taken not to leave the baby exposed for too long during prepping the operative site and draping. Using modern water-repellent material drapes and disposable waterproof drapes reduces the chance of losing heat with wet drapes being in contact with the baby’s skin for long periods.

Instrumentation

Theatre practitioners will find that the instrumentation used for neonatal surgery looks very similar to that used for adults but the tips of instruments are finer to cope with the small delicate structures. The small size sutures used necessitate delicate needleholders designed to hold and not damage size 5/0, 6/0 and smaller sutures, and the instruments are shorter because in general in neonatal surgery the surgeon is not ‘a long way down a deep gaping hole’. That is not to say that there are not times when longer instruments are required but these tend to have a slimmer body to manage the access through small incisions (e.g. if a long artery forceps is required then a Kilner or Kelly forceps which is less bulky and finer pointed rather than a Spencer Wells would be appropriate). Malleable copper retractors are widely used to provide good visualisation of the opera-tive field and when deeper retractors than cats’ paws are needed, Ragnell’s or small Langenbeck’s are used.

Neonatal Emergencies

Gastroschisis

Gastroschisis is a herniation of the abdominal contents through a full thickness defect in the baby’s abdominal wall, in the region of the umbilicus, usually to the right (see Figure 25.1 ). It is generally recognised during pregnancy and the mother delivered in a centre with facilities for neonatal surgery, to prevent the bowel being exposed for a



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prolonged period post delivery. Immediately after delivery, the baby’s abdomen includ-ing the exteriorised contents are wrapped in a plastic protective wrap to prevent heat and fluid loss from the exposed bowels. There was a time when all neonates with gas-troschisis were operated on within a few hours of birth to reduce the bowel back into the abdomen or to place the bowel into a handfashioned silo to allow the protected contents to be reduced over the next few days. The neonate would then return to the operating theatre to formally close the abdomen. Current practice in many centres is to apply a preformed silastic silo on the neonatal unit without the use of general anaes-thetic, as described by Owen et al . ( 2006 ). The bowel is slowly reduced and the abdo-men closed without the need for suturing. This is not possible for all babies with gastroschisis and the theatre practitioner working in neonatal surgery will continue to see these neonates coming through the operating theatre.

Oesophageal Atresia

The most common configuration of this condition is oesophageal atresia with distal tracheoesophageal fistula (85%) as shown in Figure 25.2 . If not identified on ultra-sound examinations during pregnancy the baby presents with excessive salivation, choking, coughing and respiratory distress or problems if passing of a nasogastric tube is attempted. Many of these neonates will also have other associated congenital abnormalities. This congenital condition requires surgery to close the fistula, thus preventing over gastric dilatation as the baby breathes, which can lead to gastric per-foration, and anastomosis of the two ends of the oesophagus to effect continuity to allow oral feeding and prevent aspiration. After birth a Replogle tube is inserted into the upper pouch of the oesophagus via the nasal route. This tube has two lumens, one inside the other, to allow small quantities of saline to be inserted via the outer tube to soften salivary secretions and suction to be applied to the shorter inner tube to pre-vent overflow of secretions into the lungs without getting blocked by sucking against the mucosa of the upper pouch. If the neonate requires artificial ventilation this

Figure 25.1 Baby born with gastroschisis.



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should be performed with low pressures to lower the risk of gastric perforation and surgery becomes more urgent.

The procedure is usually carried out through a right thoracotomy unless the neonate has an abnormally positioned aortic arch. It is possible to block the fistula using a small Fogarty embolectomy catheter inserted through the fistula with use of a rigid broncho-scope. This is of temporary benefit while performing the thoracotomy. In the very unstable neonate it may be necessary to perform a crash thoracotomy and just ligate the fistula, bringing the baby back to theatre a few days later to formally close the fistula and anastomose the oesophagus.

Some neonates with this congenital deformity will require multiple trips back to theatre to deal with further complications, such as the gap between the two ends of the oesophagus being too far apart to anastomose, requiring either gastric transposition or interposition of colon or small bowel to the gap. They can go on to develop tracheo-malacia, oesophageal strictures at the anastomosis site, food blockages in the oesopha-gus and gastro-oesophageal reflux requiring surgery.

Malrotation with volvulus

Malrotation of the gut is a congenital deformity where the distance between the duo-denojejunal flexure (DJ flexure) and the caecum is small, leaving the mid-gut mesentery on a narrow pedicle. The DJ flexure should sit to the left of the spine in line with the pylorus of the stomach and the caecum should sit down in the right ileac fossa. In this normal configuration the mid-gut mesenteric base is wide and extremely unlikely to twist. If the caecum is high and the DJ flexure to the right of the spine the mid-gut can twist, termed a volvulus (Figure 25.3 ), which cuts off the blood supply to much of the

Figure 25.2 Baby born with oesophageal atresia and distal tracheoesophageal fistula. Image courtesy of David Crabbe, Consultant Paediatric Surgeon.



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small bowel. This is a real surgical emergency and, if not treated expeditiously, can lead to much of the bowel needing to be removed and a life of living with short bowel syn-drome for the baby with complications of parenteral nutrition, malabsorption issues, bowel lengthening procedures and liver and small bowel transplant prospects for the future if the baby survives the initial period.

Surgery involves a laparotomy, untwisting the gut, straightening and bringing for-ward the duodenum, division of Ladd’s bands, widening the mesenteric base and inver-sion appendicectomy. The appendix is removed because at the end of the procedure the caecum is positioned on the left of the abdomen and if in later life the child has appen-dicitis it could go unrecognised due to the non-anatomical position. This is called a Ladd’s procedure. If any of the bowel is ischaemic and does not show signs of improve-ment following untwisting, excision of the dead segment is required.

Conclusion

Survival rates for neonates with congenital deformities are increasing due to improving neonatal services and advances in anaesthetic and surgical techniques. Babies born with oesophageal atresia in the 1960s had a survival rate of 60–70% whereas in the twenty-first century a survival rate of 90–100% is the norm (Johnson 2005 ). Duro et al . ( 2008 ) report a survival rate for short bowel syndrome of 73–89%. Improvements in introduc-ing enteral feeding and caring for these patients using a multi-disciplinary approach have enhanced outcomes. Progress in paediatric liver and bowel transplantation gives hope for better results in the future.

The theatre practitioner will find neonatal surgery to be constantly challenging as new treatments and our ability to perform new techniques, such as thorascopic surgery, on small premature babies evolves.

Figure 25.3 Malrotation with volvulus.



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References

Bhatia J ( 2006 ) Fluid and electrolyte management in the very low birth weight neonate . Journal of Perinatology 26 : S19 – S21 . Duro D , Kamin D and Duggan C ( 2008 ) Overview of pediatric short bowel syndrome . Journal of Pediatric Gastroenterology and Nutrition 47 : S33 – S36 . Johnson PRV ( 2005 ) Oesophageal atresia . Infant 1 ( 5 ): 163 – 167 . McClelland DBL (ed.) ( 2007 ) Handbook of Transfusion Medicine . London : The Stationery Office . Owen A , Marven S , Jackson L et al . ( 2006 ) Experience of bedside preformed silo staged reduction and closure for gastroschisis . Journal of Pediatric Surgery 41 ( 11 ): 1830 – 1835 .


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