Paediatric Anaesthesia "Safety and security don't just happen, they are the result of collective consensus and public investment. We owe our children, the most vulnerabe in our society, a life free of pain andfear." Nelson Mandella The child is not a small scale adult (anatomically and physiologically). The child is a human being at the beginning of the growth, development and maturation continuum. The smaller the child, the greater the difference. r/--Narrow Nares Large Tongue .... -, High Glottis---+-~ Narrow Crico1d Ring ' I I I i I I I , , , ,/ ~-..--'" ~-Babies have: Large heads Large abdomens Small chests High 02 consumption Active airway reflexes Figure 13.1 Anatomical features in infants RESPIRATORY SYSTEM Anatomy 1. Head 2. Pharynx 3. Tongue 4. Epiglottis 5. Larynx 6. Cricoid 7. Trachea 8. Airways 9. Ribs : large occiput, flat nasal bridge, short neck : shallow naso pharynx with adenoids. Soft palate flaps on the roof of the pharynx, causing airway obstruction since the infant is an obligatory nose breather up to 5 months. : large, overhanging the glottis, making laryngoscopy difficult : longer, narrower, floppy, U/ V shaped, at an acute angle to the glottis : higher, C4-5 (adults C5-6), more anterior, narrow and conical in shape : circular, the narrowest part, and prone to oedema with trauma : short (4cm), predisposing to endo-bronchial intubation : narrow, causing increased resistance : horizontal, with no "bucket handle" movement 10. Diaphragm : horizontal, easily splinted with abdominal distension
Pulmonary physiology Neonate Adult Respiratory rate I min 30-40 15 Tidal volume ml/kg 7 7 02 consumption ml/kg/min 7 3 FRC (02 stores) ml/kg 27-30 30 Oxygenation may be compromised and monitoring is extremely important. Period of safe apnoea is shorter because oxygen stores are limited due to the small FRC, and inadequate for the high oxygen consumption. Desaturation occurs due to airway obstruction, breath holding, coughing Laryngospasm is common due to increased laryngeal irritability. Airway closure occurs within tidal breathing and may need CP AP during anaesthesia with spontaneous respiration. Rate dependence : minute volume increase is by increased rate (tidal volume is fixed) Inhalational induction and recovery are rapid due to an increased respiratory rate. Apnoeic spells if <50 weeks post-conceptual age due to immature respiratory centre. Respiratory infections are common. Obligatory nasal breathing till 5 months. CARDIOVASCULAR SYSTEM Blood volume : Neonate 90ml/kg, infant 85ml/kg, child 80ml/kg Cardiac output : Rate dependent (maintained by rate, not stroke volume) Increase is limited to 30-40% (rate up to 200/min). Heart rate : 120/min at birth, rises to 160/min at lmonth, and then decreases. Bradycardia (<100/min) results in a fall in cardiac output. Bradycardia is the usual response to hypoxia, hypotension, and vagal stimulation, due to the immature sympathetic system and baroreceptor activity (as parasympathetic tone predominates). Bradycardia should be treated promptly with oxygen and atropine. Blood pressure : Systolic is 70-90 mmHg and diastolic 50-70 mmHg. Foetal shunts (PDA, ASD) open up if hypoxia, acidosis and hypercarbia cause pulmonary vasoconstriction , with cyanosis out of proportion to the cause.
TEMPERATURE REGULATION Poor temperature regulation, due to large body surface area I body weight ratio Lack of .subcutaneous fat causes hypothermia in neonates. Optimal ambient temperature is 34°C for the premature and 33°C for the term neonate. To minimize heat loss : • Increase the temperature to 25°C before the child arrives in the operating theatre. • Cover head and exposed surfaces to reduce conduction, radiation and evaporation. • Warm infusion fluids to 37°C and use warm cleaning solutions. • Use warming blankets. GLUCOSE HOMEOSTASIS Dextrose infusions maybe needed as hypoglycaemia can occur due to : • Small glycogen stores (immature liver) • Immature glucose homeostasis • Pre and post-operative starvation FLUID & ELECTROLYTE MAINTENANCE REQUIREMENTS Turnover of water and electrolytes is higher than in the adult. Dehydration occurs easily, and over hydration cannot be compensated for. Water requirement 4 ml/kg/h for first lOkg body weight (BW) 2 ml/kg/h for next lOkg BW and 1 ml/kg/h for each subsequent kg Sodium requirement 3 mmol/kg/day. Potassium requirement : 2 mmol/kg/day OTHER VITAL FUNCTIONS Hepatic : Neonatal jaundice or kernicterus Immature function and reduced blood flow Phase 1 reactions mature in 1 week, phase II in 4 months Renal : Reduced filtration, clearance, concentrating ability Unresponsive to aldosterone, delayed excretion of drugs Gastric : Dilated and incompetent lower oesophageal sphincter Blood : Hb at term is> 15g (80% HbF with reduced oxygen delivery) Physiological anaemia of infancy (HbA 1 Og at 3 months) CNS : Blood-brain barrier is more permeable in neonates with increased sensivity to barbiturates, opiates and volatile agents.
Equipment for Paediatric Anaesthesia Do not anaesthetize if suitable equipment is not available. Do not use adult equipment if the child is less than 20 kg body weight. FACE MASK Select the smallest face mask that will adequately fit (from the bridge of the nose to the chin). Transparent masks are preferable. Fruity smelling masks are available. MAPLESON F BREATHING SYSTEM (Jackson-Rees modification of Ayre's T piece) The functional characteristics of this system is similar to Mapleson D (see page 2.11). It is optimal for smaller children ( < 20kg) as it has a minimal dead space and resistance. Figure 13. 2 Mapleson F breathing circuit Dead space occupies the length of the tube between the T piece and child, and should be as short as possible. Corrugated tube (a reservoir for expired gas and fresh gas) should have an internal volume greater than the tidal volume of the child (250 ml). Re-inhaled gas will then not come from the bag where gases mix. Reservoir bag (500 ml) During spontaneous respiration, the end must be open. During IPPV or CP AP the end must be partially occluded. Fresh gas flow requirement for children is not straight forward as in adults, as the relationship between co2 production and weight is not linear.
RECOMMENDED FRESH GAS FLOWS Minimum fresh gas Dow 3L/min with 30 • 50% oxygen in all cases Spontaneous breathing : Controlled ventilation Rate of ventilation AIRWAY EQUIPMENT 2000ml + 200ml/kg/minute lOOOml + lOOml/kg/minute or 0.8 x kg body weight L/min 20 -30/rninute • Oropharyngeal airways of sizes 0-2 • Laryngoscopes with paediatric Macintosh and straight bladed Magill. eLMAsize: lif<5kg, l\/2if5-10kg, 2ifl0-20kg, 2\12if20-30kg. • ETT size : Correct size of tube is important since too large a tube will cause damage and too small a tube will increase gas leak and resistance to breathing. Internal diameter: neonates 2.5-3.5mrn, infants 4mrn, Child= age (years)/ 4 + 4 in mm At least 3 sizes around the estimated size should be available Size of tube is approximately equal to the size of the child's little finger. eETTcuff Tubes < 6.0 mm should be uncuffed, unless absolutely necessary. Children <10 years do not require a cuff to protect the larynx, as the narrowest part of their airway is the cricoid ring which is circular. Ischaemia and oedema in this region is disastrous as oedema fluid cannot escape externally because of the complete ring of the cricoid. Therefore allow a small leak around the ETI (listen for leak with the stethoscope placed just lateral to the larynx, with a normal inflation pressure of 15crn Hp). • ETT length: age/2+12cm (oral) and +15cm (nasal). Confirm placement with air entry and capnography. •Catheter mounts should be avoided to minimize dead space •Consider the use of LMA
Regional Analgesia in Paediatrics CAUDAL EXTRADURAL BLOCK • Most effective and popular block used in paediatrics • Reduces stress response and ensures smooth recovery • Used for any surgery below T6 • Urinary retention may occur. Technique 1. Induce GA. Ensure monitoring and airway management and a reliable assistant. 2. Position lateral with hips and knees bent at 90°. 3. Use an aseptic technique. 4. Palpate and feel the triangular sacral hiatus. 5. Pierce skin at apex of triangle with blunt, short 21/ 22G needle. 6. Maintain a 90° angle to the spine and pierce the sacrococcygeal membrane. 7. Aspirate gently, confirm absence of blood or CSF (dura may end at S21 S3) Stabilize the needle, and inject slowly. Do not exceed a total volume of 20ml. 8. Avoid pushing the needle further to avoid entering the dura or blood vessel. 9. A 22G catheter may be used to provide continuous analgesia upto 36h. Level of block Bupivacaine 0.25% Up to L1 0.5 ml/kg Up to TlO 1 ml/kg If T6 level is needed, 0.5% bupivacaine 2mg/kg should be diluted to 1.25 ml/kg SUBARACHNOID BLOCK Used for neonates and particularly for premature neonates. Technique l. Hold the infant in the lateral or sitting position with the body well flexed. 2. Use a 24 or 25G spinal needle or 25 or 26G hypodermic needle. 3. Insert the needle below L3 to prevent damage to the spinal cord. When free flow of CSF is seen, inject with a l ml syringe 0.5% plain bupivacaine (O. lml/kg + 0.1 ml for the needle dead space).
PENILE BLOCK Commonly used for circumcision and meatoplasty. Blocks the two dorsal nerves which supply the penis. They are derived from the pudenda! nerve which runs deep to the deep fascia (Bucks fascia), but superficial to the corpora cavernosa. The nerves are located at one o'clock and eleven o'clock positions at the base of the penis just below the symphysis pubis. Technique 1. Induce general anaesthesia and ensure monitoring. 2. Raise a skin wheal in the midline under the symphysis pubis. 3. Direct the needle laterally till a 'click' of piercing the deep fascia is felt. 4. Repeat, directing the needle to the other side. 5. Inject 0.5% bupivacaine 0.2 ml/kg. 6. Deposit local anaesthetic solution subcutaneously as the needle is withdrawn, producing a semicircular infiltration on the dorsal aspect of the penis. 7. Never use adrenaline as it will cause vaso-constriction and gangrene. Ring block is necessary for complete pain relief in circumcision as the penile block does not cover the ventral surface of the penis ( supplied by the scrotal branches). BRACIDAL PLEXUS BLOCK The axillary approach is safe for analgesia of the upper limb. Inject 0.5ml/k:g of 0.25% bupivacaine. WOUND INFILTRATION Infiltrate with 0.25% bupivacaine 0.25-0.5 ml/kg. TOPICAL ANALGESIA Local anaesthetic gel application for circumscision Local anaesthetic instilled into small open wounds Local anaesthetic soaked foam layer applied to skin graft donor sites
Anaesthesia for Neonates The neonate is not a small infant. Neonate : < 28 days extra uterine life or < 44 weeks post-conception Physiological changes at birth I. Tactile stimulation triggers the respiratory centre. 2. Lung inflation (high 02, low C02) reduces pulmonary vascular resistance. 3. Cessation of placental flow increases systemic vascular resistance. 4. Therefore the flow through the ductus arteriosus reverses. 5. The high Pa02 closes the patent ductus arteriosus (reversible for days). 6. Changes in the lung occur in the.first few hours. 7. Changes in the circulatory system continue for 48-72 hours and right to left shunts may occur with hypoxia and acidosis. Problems • Prematurity(< 37 weeks) • Respiratory Distress Syndrome • Congenital abnormalities Problems in ex-premmies • Aspiration pneumonia, respiratory distress syndrome and bronchopulmonary dysplasia (oxygen dependent) • Apnoeic spells may occur till 50 weeks post-conception • Reduced blood sugar, calcium, magnesium • Infections and sudden infant death syndrome • Danger of intra-ventricular haemorrhage and perivascular infarction • Apnoea and bradycardia post-operatively require close monitoring and apnoea alarms for 24 hours. • Cor pulmonale is possible. Airway Problems Treacher-Collins I Pierre-Robin I Goldenhar Syndromes Mandibular and maxillary hypoplasia Severe micrognathia with posterior prolapse of tongue Very difficult airway management with high risk of aspiration Airway obstruction improves in the prone position or if tongue is sutured to the lower gum.
PRE-OPERATIVE PREPARATION Pre-operative visit is essential for assessment of problems and communication with parents. Fasting guidelines Clear fluids with glucose : 2 hours Breast milk feed : 4 hours, Other milk feeds : 6 hours Premedication Vitamin K in the first week of life Atropine 0.02mglkg i. v .at induction to reduce secretions and bradycardia INTRA-OPERATIVE PERIOD Anaesthetic equipment • Mapleson F system (see page 13.4) • Straight bladed laryngoscope, different sizes of masks and airways • EIT (with stylet) size 2.5mm (pre-term), 3.0/3.Smm (full term) • 24G i. v. cannula and Hartman's solution for infusion Ensure I. All necessary equipment is available and checked 2. Drugs are drawn up in accurate dosage (in lml -2ml syringes) 3. Consultant supervision and skilled assistance Monitoring I. High Fi02 carries a risk of retinopathy so the Sp02 should be maintained at 90 -94% if the baby is< lkg or< 40 weeks conceptual age. Set high alarm at 94% and low alarm at 90%. 2. Assess ventilation by chest expansion and auscultation. 3. Capillary refilling time and blood pressure (use small cuff) 4. Precordial or oesophageal stethoscope is an excellent monitor of cardiac output (by rate and intensity of heart sounds) and ventilation. 5. ECG for dysrhythmias, particularly bradycardia. Maintain rate at 100-200/min. 6. Temperature 7. Rarely may need an arterial line and CVP. Intravenous induction Use 24G cannula and check with lml saline i.v. Flush to avoid drug incompatibility. Thiopental 2.5% solution 3mg/kg. Ketamine 2mg/kg, Fentanyl lµg/kg. Inhalational induction Use sevoflurane I halothane in oxygen, gradually increasing concentarations maintaining CP AP on the T piece.
Position for intubation Use a rolled towel under the shoulders to extend the head to improve the view of the larynx as the occiput is large, and the glottis is high and above the maximum convexity of the cervical spine. (Fig. 13.3) Intubation 1. Continue oxygen and volatile agent for 3 minutes prior to intubation. 2. Check pulse and respiration as induction is rapid. 3. Check ability to ventilate. 4. Inject suxamethonium 2mg/kg i.v. (ensure that atropine was given). 5. Ensure that laryngeal muscles are fully relaxed before intubation. 6. Request assistant to fix the shoulders on the table with the head centered. 7. Use a straight bladed laryngoscope to obtain a better view. Intubate gently. 8. Check for accurate placement by auscultation and secure the tube. Maintenance Titrate halothane 0.5% (MAC 0.75) or isoflurane 1 % (MAC 1.15). Relaxants should be titrated against effect as sensitivity is variable. e.g. atracurium 0.1 mg/kg, repeat doses as needed. Ventilation Rate 30-40/minute. A void high pressures which cause hypotension. Reversal Atropine 0.02 mg/kg i.v. with neostigmine 0.04mg/kg (total) Extubate only after respiration is adequate, and the baby is fully awake. Fluids Blood volume: pre term 90-lOOml/kg, term 80-90ml/kg Replace blood, if loss exceeds 10% of blood volume to maintain Hctat 30%. Intra-venous fluids: Hartmann's solution. 1st hour IOml/kg to compensate for fasting. Follow up with 5ml/kg/hour. Use a burette for measurement. Warm blood products when infusing with a thermostatically heating unit.
Thermoregulation Wann the theatre to 25-27° C before the baby arrives. Use a convection wanning mattress at 38° C, cover the head, and humidify the inspired gases. Ensure that all heating devices are thermostatically controlled. A void fluctuations in arterial and venous blood pressures, hypoxia and hypercarbia to prevent intra cerebral haemorrhage and reversal of shunts. POST-OPERATIVE PERIOD Management • Lateral position. • Watch for hypoxaemia and airway obstruction. • Feed orally as early as possible. • Replace GIT losses with 0.9% saline. Maintenance fluids for 1st IO kg (BW) : lOOrnl/kg/24 hours of 4% dextrose I saline (0.18%) PAIN RELIBF Neonates feel pain and need relief. • Local infiltration of the incision and local anaesthetic blocks • Fentanyl lµg/kg, morphine 0.1-0.2mg/kg i.v. at induction. • Paracetamol I0-20mg/kg pre and 8 hrly post surgery • Pethidine is better avoided due to its metabolite nor-pethidine • NSAIDs are not recommended. Complications during recovery • Hypothermia (keep the child warm) • Laryngeal oedema (dexamethasone O. lmg/kg i.v. for prevention) • Respiratory insufficiency • Apnoeic spells (use apnoea alarm). Treat with stimulation and theophylline i.v. • Convulsions due to hyponatraemia (too much dextrose should be avoided)
Common Surgical Conditions of the Newborn CONGENITAL DIAPHRAGMATIC HERNIA Herniation of abdominal contents into the thorax (commonly on the left side) compress and cause hypoplasia of the lung. Diagnosed antenatally by ultra sound scan (polyhydramnios seen). At birth : Si!denafil 1-2mg/kg orally 8hrly. Baby should be intubated and oxygen supplementation given if necessary. A nasogastric tube is used for decompression of stomach. In ICU : Optimization for 24-48h with gentle ventilation avoiding barotrauma Problems : Dyspnoea, pulmonary hypoplasia and hypertension (mortality 50%) Other congenital abnormalities of gut, heart, etc. Diagnosis: Scaphoid abdomen, absent breath sounds on one side Cyanosis, dyspnoea, tachypnoea, cardiac dextroposition Bowel sounds in thorax and X-ray confirmation Echocardiogram is needed to assess severity of pulmonary hypertension. Anaesthesia Laparotomy is not an urgent necessity, and prior ICU resuscitation is essential. Suction naso-gastric tube and ensure stability (CVP, arterial line, ETT maybe in situ). GA: Avoid Np. Avoid mask ventilation. May need bicarbonate for acidosis to avoid fetal shunts. Need elective IPPV for 24h. OESOPHAGEAL ATRESIA AND TRACHEO-OESOPHAGEAL FISTULA Pathology : Commonly a blind ending upper oesophageal pouch with a distal tracheo-oesophageal fistula. Diagnosis : Choking, cyanosis, and inability to pass a naso-gastric tube. Surgery : Right thoracotomy for extra-pleural ligation of fistula and oesophageal anastomosis. Problems : Cardiac, renal, gut and musculo-skeletal anomalies Pneumonia due to excessive oral secretions, spill over from a blind ending oesophageal pouch and aspiration through the fistula. Anaesthesia Antibiotics, physiotherapy preoperatively Nurse head up, and suction oesophageal pouch to reduce aspiration. Intubate the right bronchus and withdraw ETT till breath sounds are heard from both lungs, and the tip of the ETT occludes the fistula. Blood, secretions may block ETT. Ventilate gently to minimize gastric distension (manually during repair). Re-inflate left lung and extubate early to minimize suture line stress.
EXOMPHALOS I GASTROSCHISIS Exomphalos (omphalocele): abdominal contents herniate into the umbilical cord. The hernia is covered by a membrane. Gastroschisis : the defect of the abdominal wall is not covered by a membrane. Problems Associated gut, genitourinary and cardiac malformations Neonatal emergency due to fluid and protein loss, infection, and hypothermia May need postoperative elective ventilation for at least 24h, and parenteral nutrition INTESTINAL OBSTRUCTION Causes Duodenal, jejuna! and ileal atresias, volvulus, intussusception, meconium ileus, intestinal obstruction, malrotation of intestines, and Hirschsprung's disease. Problems Vomiting, hypovolaemia, failure to pass faeces, abdominal distension, dyspnoea, pain. Anaesthesia Naso-gastric tube to reduce distension and prevent aspiration. Rapid sequence induction retaining the naso-gastric tube. Avoid Np. Meticulous fluid and electrolyte replacement are essential. If gut resection is needed, septic shock and metabolic acidosis maybe associated needing ICU care. IMPERFORATE ANUS May need a simple anoplasty or a colostomy. Problems Extent of surgery, positioning, pain relief requiring caudal analgesia NEONATAL NECROTIZING ENTEROCOLITIS Seen in premature infants but is not a congenital disease Ischaemia of the intestinal wall causes gangrene, perforation and peritonitis. Problems Premature neonate, respiratory distress syndrome, apnoea Fluid and electrolyte imbalance, sepsis, acidosis Danger of giving Np and high concentration of oxygen (give oxygen I air)
MYELOMENINGOCELE Lack of fusion of neural tube with no bony cover for spinal canal. Distal sensory and motor loss, neurogenic bladder, and loss of sphincter function. Problems Heat loss, prone position, post operative apnoea or hyperventilation, infection CONGENITAL HYPERTROPHIC PYLORIC STENOSIS Commonly affects male infants, presents with projectile vomiting. A medical (not a surgical) emergency, and needs resuscitation prior to surgery. Problems Weight loss, dehydration, and full stomach Hypochloraemic, hypokalaemic, metabolic alkalosis Pre-operative management Correct fluid and electrolyte imbalance with 0.9% saline and 20 mmol/L of KC!. Optimize to Na >130, K >3.5, Cl >95, HC03 <30 mmol/L, and pH <7.5 Pass nasogastric tube, aspirate 4 hourly and replace with 0.9% saline and KC!. Anaesthesia Apply suction to the naso-gastric tube and pre-oxygenate. Use i.v. or gas induction, and be prepared for vomiting (high risk of aspiration). Rapid sequence inducation with suxamethonium. A void long acting relaxants. Infiltrate skin incision with a local anesthetic and extubate awake in lateral position Early post-operative oral feeding (within 6h), and tail off i.v. fluids
Anaesthesia for Infants (1 month -1 year) PROBLEMS Infants are similar to neonates. Congenital abnormalities are likely. Upper respiratory tract infections are common. PRE-OPERATIVE PREPARATION I. Parental presence (if calm) during induction may give better rapport. 2. Clear liquids 2 hr, breast milk 4hr prior to surgery (supervised by nurse) 3. Sedative should be given only if trained personnel are available to manage airway. Diazepam 0.2mg/kg or midazolam 0.1 -0.5mg/kg oral one hour before surgery 4. Weigh all children and give drugs on a mg/kg basis. 5. EMLA patch 1 hr before or Ametop 30rnin before surgery for i.v. site. 6. Atropine 0.02mg/kg i.v. with thiopentone to prevent bradycardia INTRA-OPERATIVE PERIOD Preparation Check equipment Monitoring as for the neonate Skilled assistance Induction • Give atropine 0.02mg/kg i.v. • Intravenous : Thiopental 5-7mg/kg i.v. or Ketamine l-2mg/kg i.v. or Smg/kg i.m. with fentanyl l-2µg/kg • Inhalational : Halothane or sevoflurane in oxygen Intubation l. Use a straight blade for infants below 6 months, and a curved blade over 6 months. 2. Suxamethonium 2mg/kg i.v. with atropine (avoid non depolarisng relaxants unless experienced) 3. Position infants with pillow under shoulders and head extended. 4. Children do not need a pillow (may cause flexion of the head). 5. Select ETI size to allow a small leak around the tube. 6. Carefully fix the endotracheal tube and support the breathing system as endobronchial intubation, extubation, disconnection, and obstruction due to kinking and secretions may occur. Consider the use of LMA instead of ETI
Maintenance Analgesia : morphine 0.1-0.2 mg/kg, fentanyl 1-2µg/kg, and local anaesthetic blocks. Give 30-50% oxygen in fresh gas flow. If spontaneous ventilation is used, assist manually as airway resistance is high with ETI and airway closure occurs in children <5 years during normal tidal breathing. If IPPV and relaxant are necessary note that they are sensitive to non depolarizing relaxants, and more resistant to suxamethonium. Fluids Give lOml/kg Hartmanns solution in the 1st hour and 5ml/kg thereafter. If losses are high continue at 1 Oml/kg/hr. Replace gastrointestinal losses with saline I Hartmann's solution. Reversal as for neonates Extubation Extubate awake in the semi prone position. Give oxygen and blow lungs just prior to extubation so that the child will cough out what remains in the throat without aspirating it. If laryngospasm occurs (due to extubation under light anaesthesia), treat with CPAP and 100% oxygen. If desaturating and cannot ventilate, give propofol lmg/kg, suxamethonium 0.5mg/kg with atropine lOµg/kg, and ventilate with 100% oxygen. Recovery Ensure a normovolaemic, pain free child with a stable CVS and RS. POST-OPERATIVE PERIOD • Maintain lateral position and give oxygen. • For laryngeal oedema due to ETI, give dexamethasone 2mg i.v. • Feed orally as early as possible. • Pain relief : local infiltration, local anaesthetic blocks, paracetamol 20mg/kg, NSAID, tramadol or more potent opiates (except pethidine) as needed. • Fluid maintenance with 5% dextrose and 0.45% saline lOOml/kg for first 10 kg BW 50 ml/kg fornext 10 kg BW 25 ml/kg for every extra kg BW
REPAIR OF CLEF!' LIP AND CLEF!' PALATE Cleft lip can occur with or without cleft palate. Cleft lip repair is usually done at 2-3 months and cleft palate at 6 -12 months. This allows anatomical and physiological maturity and detection of other defects. Skilled assistance is mandatory. Pre-operative assessment Associated defects such as Pierre Robin Sequence, Treacher Collins, Goldenhar, Down's, Klippel-Feil syndromes have difficult airways. Assess the profile for retrognathia. Assessment of the airway is difficult in this age group as they cannot cooperate. Congenital cardiac and renal abnormalities are common. Exclude other infections such as URTI, chest signs and otitis media. Intra-operative period Anticipate difficult layngoscopy in children with bilateral clefts and receding chin. A bougie and laryngeal mask should be kept available. If difficult laryngoscopy is anticipated : 1. Place a gauze roll in the cleft if the laryngoscope blade tends to slip into the cleft and use a straight bladed laryngoscope. 2. Induce with sevoflurane I halothane in oxygen or i.v. 3. Check the ability to ventilate before giving suxamethonium for intubation. 4. Slide laryngoscope blade from the left angle of the mouth and direct the tip of the blade towards the midline to visualize the cords to prevent trauma to the cleft and bleeding. 5. Optimal external laryngeal pressure improves the view of the larynx. 6. If laryngoscopy is difficult, flexion of the child's neck may help to visualize the larynx rather than further extension. Check ETC02 soon after intubation. 7. Insert a throat pack and check for obstruction of the ETT when the split mouth gag is in place. Tube occlusion and displacement can occur at any time. 8. RAE tube is preferable as it does not interfere with the surgical site. 9. IPPV is best with low concentrations of inhalational anaesthetics for early recovery. Recovery Request the surgeon to remove the pack and suction throat to avoid damage to repair. Pain relief is best given with morphine O.l-0.2mg/kg i.v. at induction, and an infra orbital block or paracetamol suppositories post-operatively. Extubate awake in the left lateral position.
Anaesthesia for Children PAEDIATRIC BRONCHOSCOPY Indications 1. Diagnostic procedure (for tracheomalacia, fistulae, biopsies, haemoptysis) 2. Dilatation, stenting, laser therapy 3. Removal of foreign bodies, secretions, mucous plugs, etc. (maybe emergency) Problems Anxious child and parents Full stomach as the child often chokes while eating Airway obstruction to varying degrees and potential loss of airway Airway shared by the anaesthetist and endoscopist Mucosal oedema and chemical pneumonitis (following aspiration of peanut) Hyperinflation or consolidation distal to obstruction seen on X ray (following peanut) Pre-operative Assess for airway obstruction, pneumonia, wheezing, dehydration. Xray chest for hyperinflation or consolidation Give dexamethasone 0.1 mg/kg i. v. to prevent laryngeal oedema post-operatively. Anaesthesia l. Establish monitoring and check all equipment. 2. Induce with sevoflurane I halothane in oxygen or i. v. induction if cooperative. 3. l.v. access and atropine 0.02mg/kg i.v. to prevent bradycardia and secretions 4. Spraying the larynx with 2% lignocaine may induce laryngospasm and coughing. 5. Suxamethonium may be used for intubation. 6. Intubate to increase depth of anaesthesia, and hyperventilate to wash out COr 7. Remove endotracheal tube to allow passage of bronchoscope. 8. If desaturation occurs, withdraw bronchoscope to trachea and give 02• 9. Attach the circuit to the ventilating bronchoscope (Storz). 10. Allow spontaneous ventilation with 02 and halothane (C02 rise is a problem), but with good control of ventilation muscle relaxants can be used. 11. Muscle relaxants and controlled ventilation should not be used : o for foreign bodies and implantable polyps in case _they are pushed further o if hyperinflation is seen on Xray and a ball-valve effect is suspected 12. Apnoeic technique or TIV A with propofol may also be used. Recovery • Reintubate and ventilate till recovery and extubate awake. • Assess for complications : stridor, spasm, tissue trauma, pneumothorax, etc. • Nebulise with salbutamol and adrenaline after extubation
Upper Respiratory Tract Infections Common problem often seen on the pre-operative visit. Mostly viral, but bacterial, middle ear and tonsillar infections are also seen. Problems Congested mucosa and partial aitway obstruction Laryngospasm and bronchospasm (with both LMA and ETI) for 8 weeks Bacteraemia and chest infection If snuffly but afebrile, there is no need to cancel surgery. LMA is safer. If febrile >38°C, cough with purulent secretions, red ear drum or chest signs, vomiting, or anorexic, postpone surgery for 1 month. ACUTE EPIGLOTTITIS Diagnosis Rapid onset, increasing respiratory distress in a pyrexial, toxic child (1-7 years) Stridor, tachypnoea, drooling, inability to swallow, sitting up with neck extended Management A medical emergency Calm the child and parents. Do not disturb with i.v. or X-ray. ENT surgeon must be present and ready for tracheostomy. Keep child sitting in parent's arms for sevoflurane I halothane I oxygen induction. When deeply anaesthetized, obtain i.v. access. Give atropine 0.2mg i.v. before laryngoscopy. Pass a small oral ETI, change to nasal later, and sedate to keep ETI for 24-48 hours. Give antibiotic (cefuroxime) for Haemophillus influenzae B. LARYNGO· TRACHEO-BRONCHITIS (CROUP) Slow onset stridor with mild pyrexia, a· harsh cough and profuse secretions in a child 6 months to 6 years with airway oedema and obstruction. Nebulize with adrenaline in cool humidified air/02• May need intubation.