Paediatrics (Oct-2008 Q7) A 6yo girl with severe spastic cerebral palsy presents for orthopaedic surgery to correct lower limb deformities. Outline the implications of cerebral palsy for anaesthesia management for this operation. 32% Cerebral Palsy Non-progressive motor disorder. Due to a brain lesion, arising in its early development Clinical picture: Normal intellect with monoplegia to mental retardation with total body spasticity Implications of CP for Anaesthesia Management: PREOP - Ensure general medical condition is optimized - Evaluate peri-op risk - As screening questions for Latex allergy - Explain anaesthetic procedure - Particular problems with CP: - CNS: Communication difficulties Contractures ( difficult IV access and positioning ) Epilepsy : Sodium valproate may increase bleeding due to platelet dysfunction. - CVS : Prolonged QT and Vtach due to Cisapride - RESP: Aspiration, Recurrent chest infection, pooling of secretions, poor cough, restrictive lung disease ( scoliosis ), sensitive to opiates. - GIT: GORD, constipation, malnutrition INTRA-OP: INDUCTION: - Challenging due to poor communication, cooperation, difficult IV access. - Gas induction = risky due to drooling and GORD - For RSI: Sensitive to Sux, resistant to Vec MAINTENANCE: - MAC is 20% Lower - Hypothermia is common - Pressure sores and nerve damage must be prevented with attention to positioning and padding - Epidural with 0.125% Bupivacaine + 2 mcg/ml Fentanyl is best for analgesia ( Clonidine can be added ) SURGERY: - Often prolonged, painful and potentially bloody. - Often need SPICA plaster at the end and risk loosing the airway and epidural catheter with positioning for SPICA. POST-op: - MONITORING for resp depression, pain, PONV - May need higher level of nursing care - Treat PONV with Ondansetron 0.1 mg/kg - Epidural provides excellent analgesia. Rate 0.1-0.4 ml/kg/h - Baclofen +- Diazepam can be added for problematic spasms
(May-2008 Q8) You are asked to provide assistance to r esuscitate a baby. One minute after birth the baby is apnoeic, grey/blue all over, floppy and unresponsive to stimulation, with a pulse felt at the umbilical stump of 60/min. What is this baby's APGAR score? Describe your resuscitation of the baby. ANDREW
APGAR as per Dana’s mnemonic A ppearance, or color: 2 = pink all over; 1 = acrocyanosis acrocyanosis,, trunk and head are pink, but arms and legs are blue; 0 if the whole body is blue. Newborns Ne wborns with naturally darker skin color will not be pink. Pulse rate: 2 = pulse > 100 bpm; 1 = pulse pulse < 100 bpm; 0 for no pulse. Heart rate is assessed by listening with a stethoscope Grimace (reflex irritability): 2 if the neonate coughs, sneezes, cries in response to a stimulus (such as the use of nasal suctioning, stroking the back to assess for spinal abnormalities, or having the foot tapped); 1 for a slight cry or grimace in response to the stimulus; 0 for no response. Activity, or muscle tone: 2 for vigorous movements of arms and legs; 1 for some movement; 0 for no movement, limpness. espirations: 2 for visible breathing and crying; 1 for slow, weak, irregular breathing; 0 R espirations: for apnea, or no breathing. Respirations are best assessed by watching the rise and fall of the neonate's abdomen, as infants are diaphragmatic breathers. Calculation of APGAR score for this child. Blue all over = 0 Pulse of 60 = 1 Unresponsive = 0 Floppy = 0 Apnoeic = 0 Total = 1 Baby should be dryed and wrapped during performance of APGAR assessment to prevent heat loss. Neonatal resuscitation
1. Open Open Airw Airway ay If not already done I would initially open the babies airway by gentle chin lift with the head in the neutral position p osition and assess for spontaneous ventilation in the presence of an open airway.
2. 5 Inflation breaths (2-3 secs, 30cmH20) and assess for chest movement 3. Reas Reasse sess ss hear heartt rate rate 4. If there is is no response – apply apply jaw thrust thrust and repeat repeat 5 inflation inflation breaths 5. If there is is still no response response – inspect inspect and suction suction oropharyn oropharynx, x, consider intubation, repeat inflation breaths a third time. 6. Intubation Intubation – ETT size size is based on weight. weight. Predict Predicted ed weight weight at term = 3.5kg. 3.5mm I.D., 9.5cm at lips 7. If there is is adequate ventil ventilation ation and heart heart rate remai remains ns <60 commence chest compressions. Rate 120/min. Compression:Breath ratio 3:1. 8. Reassess HR every 30s and cease compressions when heart rate is increasing
(May-2008 Q8) You are asked to provide assistance to r esuscitate a baby. One minute after birth the baby is apnoeic, grey/blue all over, floppy and unresponsive to stimulation, with a pulse felt at the umbilical stump of 60/min. What is this baby's APGAR score? Describe your resuscitation of the baby. ANDREW
APGAR as per Dana’s mnemonic A ppearance, or color: 2 = pink all over; 1 = acrocyanosis acrocyanosis,, trunk and head are pink, but arms and legs are blue; 0 if the whole body is blue. Newborns Ne wborns with naturally darker skin color will not be pink. Pulse rate: 2 = pulse > 100 bpm; 1 = pulse pulse < 100 bpm; 0 for no pulse. Heart rate is assessed by listening with a stethoscope Grimace (reflex irritability): 2 if the neonate coughs, sneezes, cries in response to a stimulus (such as the use of nasal suctioning, stroking the back to assess for spinal abnormalities, or having the foot tapped); 1 for a slight cry or grimace in response to the stimulus; 0 for no response. Activity, or muscle tone: 2 for vigorous movements of arms and legs; 1 for some movement; 0 for no movement, limpness. espirations: 2 for visible breathing and crying; 1 for slow, weak, irregular breathing; 0 R espirations: for apnea, or no breathing. Respirations are best assessed by watching the rise and fall of the neonate's abdomen, as infants are diaphragmatic breathers. Calculation of APGAR score for this child. Blue all over = 0 Pulse of 60 = 1 Unresponsive = 0 Floppy = 0 Apnoeic = 0 Total = 1 Baby should be dryed and wrapped during performance of APGAR assessment to prevent heat loss. Neonatal resuscitation
1. Open Open Airw Airway ay If not already done I would initially open the babies airway by gentle chin lift with the head in the neutral position p osition and assess for spontaneous ventilation in the presence of an open airway.
2. 5 Inflation breaths (2-3 secs, 30cmH20) and assess for chest movement 3. Reas Reasse sess ss hear heartt rate rate 4. If there is is no response – apply apply jaw thrust thrust and repeat repeat 5 inflation inflation breaths 5. If there is is still no response response – inspect inspect and suction suction oropharyn oropharynx, x, consider intubation, repeat inflation breaths a third time. 6. Intubation Intubation – ETT size size is based on weight. weight. Predict Predicted ed weight weight at term = 3.5kg. 3.5mm I.D., 9.5cm at lips 7. If there is is adequate ventil ventilation ation and heart heart rate remai remains ns <60 commence chest compressions. Rate 120/min. Compression:Breath ratio 3:1. 8. Reassess HR every 30s and cease compressions when heart rate is increasing
9. Continue Continue ventil ventilation ation if not not breathi breathing ng 10. If HR not improving, consider giving drugs. Drug RX includes includes Adr 1:10000 1:10000 1ml/kg 1ml/kg via ETT Adr 1:10000 0.1-0.3ml/kg IV NaHCO3 4.2% 2-4ml/kg IV Dextrose 10% 2.5-5ml/kg IV Volume expander = O neg blood, 0.9%NaCl 10-20ml/kg IV Note – Curr Opin Anes r/v on paediatric resusc from 2008 – states studies on neonatal resusc have consistently found room air to be superior to 100% oxygen (which may even ev en be associated with a worse outcome). Only change to 100% O2 if the neonate remains bradycardic or cyanotic after 90s of ventilation with room air. Arterial oxygen saturation in healthy neonates is only 70-90% in the ten minutes following birth without causing brain damage – realistic sats target of 94% may reduce risk of retinopathy.
(May-2008 Q11) You are the anaesthetist at a childrens' hospital. A 3yo schedules for dental restoration and extractions is found to have a systolic murmur during your preoperative assessment on the day of surgery. They have been on a waiting list for 6 months and have had a dental abscess that settled with antibiotics. Describe how you would evaluate the significance of this murmur and how this decision would affect your decision to proceed or not with surgery. DALE Marks were awarded for appropriately evaluating the significance of the murmur by history and examination (6 marks) and integrating the information obtained into a decision to proceed or not (4 marks). Good answers addressed the key elements of the question including the setting in a Children’s Hospital where ready access to cardiology services is likely, it is a three year old with a systolic murmur, the commonest age for common innocent murmurs, the procedure is at a high risk for bacteraemia and bleeding, the parents have been waiting for six months, have already treated a complication and would be anxious and probably very keen for the case to proceed, there are stresses and costs involved in cancelling elective surgery for families and staff. To pass candidates had to note that the aim in evaluation is to differentiate between innocent physiological murmurs that are of little consequence and structural abnormalities that warrant investigation pre-operatively. pre-operatively. Candidates had to mention some of the symptoms symptoms and signs of heart failure and heart disease in children and the distinguishing characteristics of an innocent vs pathological murmur. Better answers noted that bacterial bacterial endocarditis is also possible with with a history of dental abscess and the possibility possibility of a new heart murmur. Better answers also noted that a happy, active thriving child is unlikely to have a significant murmur, and the place of pulse oximetry and an ECG as simple investigations. There were various appropriate options for proceeding or not depending on evaluation as to the significance of the murmur murmur and any reasonable discussion gained a pass. In the absence of symptoms or signs, with a typical innocent murmur, with a normal ECG, it would be reasonable to proceed with the surgery. In a Children’s Hospital, Hospital, if this was the first time time the murmur had been noted and or the anaesthetist was inexperienced, it would be very reasonable to consult a cardiologist on the day of surgery, alter the operating list accordingly and schedule the operation for later in the list. The cardiologist would then have time time to perform an echocardiogram if indicated. Antibiotic prophylaxis with amoxicillin pre op or at induction would not be indicated for an innocent murmur but would be if pathological. Any delay for a suspected pathological murmur would require a sympathetic and informed discussion with the parents and the surgery should proceed without in-ordinate delay after cardiological review perhaps with an overnight admission and surgery the next day. Extra marks were gained by: A Flow Chart showing showing a Management Algorithm, appreciation appreciation of an ability to re-organize consultations and operating lists in referral hospitals, brief mention of new NICE and AHA Endocarditis prophylaxis guidelines, and the role of pre-operative trans-thoracic
echo by experienced anaesthetists. The most common murmurs in children of this age are physiological murmurs that occur in up to 72% of children. Pathological murmurs only occur in 0.5%. History: • • •
• •
•
Full anaesthetic history Birth history Developmental and growth history o Failure to thrive o Behavior History of other significant illnesses or syndromes Cardiac history including: Previously noted murmur o o Family history of congenital heart disease o Episodes of cyanosis, shortness of breath, wheezing, syncope or recurrent respiratory infections o Exercise tolerance History of previous dental abscess o Possibility of bacterial endocarditis
Examination: • • •
• •
Check weight for percentiles General inspection to assess if they are well and look active Cardiac examination Full examination looking for stigmata of cardiac d isease (cyanosis, clubbing, etc) o o Pulse for rate, rhythm and radio-femoral delay Palpate the praecordium for thrills or heaves o Physiological murmurs do not cause thrills o Auscultate the heart Physiological murmurs are usually ejection systolic, ≤ 3/5, no thrills and disappears with standing and increases with squatting Pathological murmurs are louder and longer (continuous, pan systolic or diastolic) Respiratory exam for evidence of hea rt failure Palpate for hepato-splenomegally
Investigations: • •
•
Pulse oximetry may show decreased saturations with significant right to left shunt ECG for evidence of hypertrophy indicating aortic stenosis or hypertrophic cardiomyopathy If unsure about the nature of the murmur or the patient has symptoms or signs of cardiac disease they will require an echocardiogram
Consultation: •
If concerned a cardiologist should be consulted. In a paediatric hospital they may be able
to see the child that morning and perform an echocardiogram to rule out significant cardiac lesions. Plan: •
•
•
•
If the child is active, happy and thriving they are very unlikely to have a significant cardiac lesion This child has already suffered a complication of their dental disease and delaying surgery should be avoided if possible If cardiology review is required the operating list should be rearranged or the patient may need to be delayed for a few days (the minimal time possible given previous abscess) According to the current Australian Therapeutic Guidelines (TGA) Bacterial endocarditis prophylaxis is only required if the child has an unrepaired cyanotic defect, a repaired defect with prosthetic material (prior to endothelialisation in 6 months) or repaired defects with residual defect who are u ndergoing select dental, respiratory, genitourinary or gastroenterology procedures
(Sep-2007 Q12) A 3 week old male infant who was born by uncomplicated vaginal delivery at term presents with projectile vomiting for 2 weeks. His weight is now 2.8 kg from a birth weight of 3.1kg. His presumed diagnosis is pyloric stenosis. His blood chemistry results are: Measured Normal Range Na 129 mmol/L 135-145 mmol/L K 3.0 mmol/L 3.5-5.5 mmol/L Cl 84 mmol/L 95-110 mmol/L HCO3 36 mmol/L 18-25 mmol/L Creatinine 69 μmol/L 20-75 mmol/L Glucose 3.0 mmol/L 2.5-5.5 mmol/L Explain how these abnormal results come about. Describe an appropriate fluid resuscitation regime for this infant. List the laboratory criteria by which you would consider him sufficiently resuscitated for surgery. DANA
Pyloric stenosis affect males 4:1 to females and about 3/1000 incidence… It is a medical and not a surgical emergency. Need thorough resuscitation prior to surgery. Surgical repair is a pyloromyomyotomy (often laprascopic nowadays) Explanation of biochemistry results…. 1. vomiting leads to a loss of water and Hydrogen and chloride ions to a large degree. And a variable degree of Na and K ion losses also…. Ie patient becomes alkalotic (high plasma HCO3 levels) 2. the increased bicarb load to the distal tubule of kidney results in alkaline urine and a loss of sodium and water also. Ie alkaline urine. 3. Dehydration and stress leads to activation of RAS, resulting in attempted sodium conservation but significant loss of potassium from the urine. This is the main source of potassium loss from the body resulting in Hypo K. 4. ADH secretion and water retention, Na loss in gastric contents and sodium loss linked to HCO3 in kidneys contribute to the hypo Na. 5. As they deteriorate the kidneys now try to maintain K and Na by exchanging with H ions resulting in a worsening alkalosis and paradoxical acidic urine. Resuscitation - May take 24-48hours to adequately rehydrate prior to surgery - for severe dehydration (ie > 15% loss of body weight), with severe alkalaemia a bolus of 20mls/kg should be given to correct intravascular fluid deficits. Either NS or a colloid (haemaccel or gelofusin). - For mild to moderate dehydration use 5%glucose and ½ normal saline at 6-8mls/kg/hr with 10mmol KCL in each 500ml bag).
-
Nasogastric losses are replaced with normal saline ml for ml. Repeated capillary and venous blood samples are used to guide therapy pre-op - Once targets are achieved 4% and 1/5 NS with 10mmol KCL in each 500ml bag can be used as maintenance at 4mls/kg/hr Targets for resuscitation Ideally all lab markers should be normal before proceeding. Howevere priority to normalizing serum chloride and bicarb (indicating correction of alkalosis) is paramount. Cl > 105mmol/L for vast majority of infants to have no residual alkalosis. Other markers Na > 135 mmol/L HCO <26 mmol/L Urine Cl > 20mmol/L Urine output >1ml/kg/hr
FOR INTEREST; LEVELS OF DEHYDRATION Mild: fluid loss as % of body weight is 5% Essentially everything normal and urine output is <2mls/kg/hr Moderate: 10% weight loss Anterior fontanelle is sunken Sink turgor decreased Mucous membranes dry Eyes sunken Pulse increased Respiration tachypnoea UO <1ml/kg/hr Severe: 15% weight loss all more extreme changes to moderate (ie greatly) UO <0.5mls/kg/hr
(May-2007 Q4)A 2 year old child has burns to lower body from immersion into a hot bath. Describe your assessment and management of pain and fluid requirements in the first 2 hours following injury. JAYNE • A reasonable approximate assessment of the extent of the burn – ie depth and area (using appropriate body surface area percentage charts modified for small children). • An appropriate fluid regimen eg Parkland formula starting from the time of the burn, using a balanced salt solution. • An appropriate pain assessment (observational rather than by direct questioning at this age) and appropriate acute pain management, recognising the need for titration of opiates in a potentially shocked child.
Burns to the lower half of this childs body would mean that this 2year old (12kg) would be in a significant amount of pain and will be requiring appropriate fluid resuscitation for the size and depth of the burn. Due to the age of the child (and possibly also his distress) I would be unable to assess them with direct questioning. In assessing this childs pain I would take into account: Likelihood for severe pain – ie severity of injury – requires examination Behavioural responses and interaction with parents and environment (ie is the child consolable) There are several composite pain scores for infants and children which incorporate – crying, verbal expression, facial expression, torso position, touch and leg position (Childrens Hospital of Eastern Ontario), or face, legs, activity, crying, consolability (FLACC) Pain of this severity will require titration of intravenous opioids – for adequacy of analgesia and also swiftness of action. I would use an initial bolus of 0.1mg/kg morphine, wait 15 mins and then slowly titrate 0.05mg/kg every 10mins until the child had been adequately analgesed. Noting that the child may be intravascularly depleted from the burns, I would monitor vital signs throughout In regards to fluid management in this case I would use the Parkland formula. In order to be able to use this formula I will require an estimation of the %BSA of the burn. For paediatrics there are age specific charts which assist in the determination of this %. The parkland formula (4 x %BSA x weight = fluid resus for first 24 hrs from the burn injury). Half of this (2 x %BSA x weight) is given in the first 8 hours. Normal saline would be my fluid of choice I would also calculate maintenance fluids and add them onto the fluids required for the burn ?what is the maintenance fluid of choice in kids currently
(Sep-2006 Q10) Discuss in detail the technique of rapid sequence induction with cricoid pressure in a child. Include the reasons for your choice of relaxant. JUSTIN 42% Indication for rapid sequence induction will alter the technique and agents used. Specifically, 1. haemodynamically unstable then I would substitute IV ketamine instead of propofol. 2. trauma, would require manual in line stabilization by a third assistant, minimization of neck movement and use of bougie early. Having performed usual preop assessment of pt, including Hx, Ex and review of Ix and gaining consent for required intervention from pts parents – who I would allow to stay in anaesthetic room but not allow in theatre, organized appropriate premedication, having checked my anaesthetic machine and ancillary equipment, ensuring adequately trained assistance was available and drawing up and labeling of r outine and emergency drugs I would procede to start anaesthetic. I would draw up suxamethonium (providing no CI’s)as relaxant of choice, as it is fast onset, predictable and fast offset and produces excellent conditions for intubation. It is the gold standard agent. It’s fast action removes need to ventilate before tube is placed, reducing risk insufflating stomach and regurgitation. It’s fast offset allows return of spontaneous ventilation should problems arise. However, in the case of a male child less than 10 (may have occult muscle disorder), confirmed muscle disorder, paralysis, burns, high K+, etc I would choose rocuronium) 1. Premedicate with 5 mcg/kg glycopyrrolate IM 30 min prior to reduce secretions and guard against bradycardia from sux 2. Communication. Ensure assistant knows requirement for RSI, check knowledge of bimanual technique and identification of cricoid cartilage 3. Gain IV access 4. Preoxygenation – most difficult in preschool children. Must accept compromise between oxygenation and reducing stress response (increased O2 demand) from child. Accurately fitting mask – should fit in groove between chin and lower lip. 5. Position- neonates adopt a neutral position –smaller children do not need a pillow, may lead to unwanted head flexion. - older children use normal 6. Induction – IV induction with 3-6 mg/ kg thio and 1.5 mg/kg sux. Apply cricoid pressure once eyelids droop. Bimanual technique should be used in young children, with one hand behind neck to prevent unwanted flexion of head and distortion of anatomy. 7. Intubation – Laryngoscopy should be attempted once fasciculation has ceased (fasciculation may not be present in younger children). Curved blade easier over 6 months. Intubation should be abandoned after two failed attempts and the patient should be woken up to avoid arterial desaturation. Thereafter, experienced assistance should be obtained and alternative strategies sought. 8. Securing tube. More meticulous the younger the child as accidental extubation and endobronchial intubation more common. If uncuffed tube is used then a throat pack may be used to prevent intraop aspiration – but no help for high risk times of induction, emergence (unless you forget to remove it!) 9. Ancillary – NG tube should be placed routinely (most aspiration on extubation)
(Sep-2005 Q1) What are the indications for tracheal intubation in a 3 year old who presents with "croup"? Describe your technique for intubation. LINDA 76% Croup = acute laryngo-tracheobronchitis. Usually < 2 yo, due to RSV Gradual onset (24-72h) Insiratory stridor, barking cough Fever rarely >39°C The obstruction is below the level of the cords. Less than 1% requires intubation: Assess breathing EFFORT( tracheal tug, grunting), EFFICACY(chest movement, Sats ) and EFFECTS ( ALOC due to hypoventilation ) Indications for intubation: - Resp distress - RR>55/min - HR>170/min - Obtunded child - Hypoxaemia ( PaO2 <50 mmHg) - Hypercarbia TECHNIQUE FOR INTUBATION: PREAPARATION: - Trained assistant - IV access equipment 22G and 24G cannulae. Hartmans Solution with Burette - Standard college monitoring - Equipment: Variety of ETT’s, start with 1 size smaller ( eg ETT 4.0 for this child ), curved + straight laryngoscope blades, paed difficult airway trolley. - Drugs: Thio, Sux, Atropine, Atracurium: Drawn up in Paed concentrations, with dose for this child in the syringe. INDUCTION: - Gas induction with Sevoflurane - Ensure deep before giving Sux @ 1.5 mg/kg - Intubate with MacIntosh blade - Usually no problem visualizing the cords - There is unlikely to be a leak around the ETT, until the inflammation has resolved. - By using the Nasal route for intubation, allows for superior fixation and facilitate pt care in PICU.
(May-2004 Q12) Working in a small obstetric unit you are asked to attend at the birth of a child where there is meconium stained liquor. How will you manage the infant's resuscitation? ANDREW
Marks were rewarded for an assessment of the situation and a graded resuscitation response according to current neonatal ACLS Guidelines. Better candidates mentioned labour history, foetal distress, preparation of equipment and assistance and a follow up plan.
Meconium stained liquor (MSL) is a common event, occuring in up to 10% of births. MSL can result from fetal distress (vagal stimulation from head or cord compression may cause peristalsis and relaxation of the anal sphincter) but does not necessarily indicate the need for advanced life support. Meconium aspiration syndrome (MAS) is a rare event that complicates some deliveries in which there is MSL. MAS has a high mortality and accounts for 2% of perinatal deaths. It is necessary when attending a delivery of a baby with MSL to 1) seek signs of, and risk factors for, fetal distress and 2) prepare for neonatal resuscitation if required. Assessment of the situation: Introduce yourself to the parents and explain your role Obstetric history • • •
• •
Gestational age Previous pregnancies and outcomes Risk factors in this pregnancy – Gestational diabetes, breech, IUGR, fetal anomaly, pre-eclampsia, maternal opioid use Plan for this delivery (as per obstetrician) expected time to delivery – urgency of assistance, notify NICU
Investigations •
•
examine CTG for signs of fetal distress (e.g. late decelerations on CTG, acidotic scalp pH) check fetal scalp pH if done
Equipment check, •
General – flat surface, ideally a humidicrib with warming, gloves, adhesive
•
•
•
tape, towels Airway - ensure a range of sizes of facemasks, oropharyngeal airways, ETT’s (size 2.5 to 4), laryngoscopes with 0 and 1 straight blades, a means of positive pressure ventilation (ie bag-valve-mask), oxygen supply, suction with catheters at least 12Fr Other – Nasogastric tube, stethoscope, device to clamp cord, scissors, umbilical cannulae Drugs - drawn up in doses appropriate for a 3 kg neonate Adrenaline 10 mcg/kg (ETT adrenaline if necessary) Bicarbonate 8.4% diluted 1:1 with 10% dextrose – 2-4 ml/kg or Bicarbonate 1 mmol/kg slowly Dextrose 10% 2-3 ml/kg (myocardial glucose stores) Naloxone 100 mcg/kg (avoid if maternal addiction) Fluid 10 ml/kg 0.9% Saline if bleeding suspected & arrange 0-negative blood
Neonatal Resuscitation Most babies, even those born apnoeic, will resuscitate themselves given a clear airway. There is no longer a role for suctioning the oropharynx on delivery of the head. Most babies who aspirate meconium will have done so already in utero. Await delivery of the shoulders, then start the clock. If the baby is vigorous then suctioning offers no advantage (shown by RCT). Dry, wrap, assess Apgars and hand to the parents. If, after drying and wrapping, the baby has apnoea or inadequate respirations, heart rate < 100 or is floppy then inspect the oropharynx with a laryngoscope and aspirate any particulate meconium with a wide bore catheter. If intubation is possible and the baby is still unresponsive pass an endotracheal tube and use it to suction the trachea with suction pressures < 100mmHg (9.8kPa). Call for help if required. If intubation cannot be achieved then clear the oropharynx and start mask ventilation with 5 inflation breaths. If HR falls below 60 at any point begin inflation breaths immediately. At this point it is appropriate to follow the standard Newborn Life Support algorithm (see separate document attached with this email). Depe nding on outcome of resuscitation the aby may require transfer to NICU.
(May-2004 Q13) Describe the characteristics of a ventilator suitable for neonates. DALE (59% pass) DALE Examiners Comments: • •
•
•
•
• •
•
Some excellent answers detailing why Neonatal ventilators need to be different. Some candidates just listed anything they knew about ventilators, without explaining why neonates are different. Volumes to be measured are extremely small, and compliance of the equipment can alter the results. Adult ventilators can be used with appropriate monitoring. (But to accurately measure tidal volume is difficult). Candidates would talk about measuring respiratory rate, tidal volume etc, but then not say what is different about the neonate. Others mentioned values for a neonate that were not appropriate. Candidates who did not know a lot, often wasted time by repeating themselves again and again, and saying the same thing a number of different ways, as if by filling the page they may get more marks. High frequency oscillatory ventilation is done in the Neonatal Intensive Care (8-12 cps).
Neonates are children in the first 28 days post delivery. They can range from 16 weeks premature to 4 weeks post full term delivery. Neonatal lungs have lower compliance, higher airway resistance and are more susceptible to damage from ventilation. There may already be neonatal lung disease present. Neonates therefore require ventilators with appropriate settings for a neonate. Ventilator Characteristics for Neonates: • • • • • • • • • • •
Approved for use in neonates Reliable, simple maintenance and cleaning Easy to use Portable Deliver accurate fractional inspired oxygen Deliver and measure small volumes Able to set pressure limits to prevent excess peak airway pressure Capable of high frequency ventilation for high respiratory rate Able to do inverse ration ventilation Delivers PEEP and CPAP Modes of ventilation: o Volume controlled ventilation Need to deliver precise small volumes Difficult as there may be significant leak around the endotracheal tube and variable compliance in the circuit o Pressure controlled ventilation Commonly used Decreases risk of barotrauma and pneumothorax Able to compensate for leak
Unable to compensate for decreased compliance, bronchospasm or endotracheal tube obstruction o Synchronized intermittent mandatory ventilation Requires very fast response rate due to high respiratory rate o High frequency oscillatory ventilation Used in neonatal intensive care for specific patients with neonatal lung disease Rate of 3-15 Hz T-piece circuit should always be available in case the ventilator has difficulty due to changes in the neonates compliance
•
Circuit characteristics: •
• • • •
Low compliance Prevents volume being absorbed in the tubing and delivered after the inspiratory o phase of ventilation Low dead space Low volume and minimal resistance to decrease work of breathing Able to humidify and warm inspiratory gases Compatible with nitric oxide d elivery
Monitoring: •
• • •
Gas analyzer should be close to the airway with a minimum volume extracted from the circuit and a good response time Continuous and accurate pressure monitoring in circuit Able to measure small expired volumes Alarms: Disconnect o o High or low pressure o Low delivered volume Hypoxic gas mixture o
(Sep-2003 Q2) A 4 yo boy weighing 15kg presents for day surgery repair of a left inguinal hernia for which you plan general anaesthesia and caudal block. He has no significant past history, and is well. Justify your choice of agent(s) for caudal injection for this child. DANA
Caudal blocks provide reliable and good quality analgesia which is particularly useful for day surgery. The technique is relatively simple and has a favourable risk to benefit ratio. An surgical stimuli on the body supplied by lower thoracic (T8-12), lumbar or sacral nerve roots can be reliably blocked by caudal 1st agent is obviously local anaesthetic solution. Bupivacaine, levo or ropivacanie are the most commonly used. - the higher the concentration the longer the duration of analgesia and higher incidence of motor block - the larger the volume, the greater the spread and the lower the concentration that may be used (ie need balance between volume, and dose) - I would choose ropivacaine over bupivacaine as Lower incidence of motor block o o Higher safe dose o Less cardiotoxic cf bupiv Local vasoconstrictor effect decreases systemic uptake cf o bupiv Suggested solutions for caudal Block to S1 Ie circumcision/hypospadious repair Neonate 0.5mls/kg of either .2% rop or .125% bupiv Infant/child 0.5ml of either .375%ropiv or .25 bupiv
Block to T8 Inguinal hernia repair, orchiopexy Neonate 1ml/kg of .2% rop or .125% bupiv Infant/child 1ml/kg of .375% rop or .25% bupiv
Therefore in this child who needs a higher block I would use 15mls of a .3-.375% solution of ropivucaine to achieve a good block and post op analgesia Additivies can be added to caudal block. Ketamine, clonidine or opioids have become routine practice Ketamine: intrinsic analgesic effect comparable to .25% bupivacaine, but used as an adjunct to prolong duration of block. Ketamine
0.5mg/kg increases duration of analgesia by upto 8hours. At this dose no significant SE, there is a theoretical risk of oversedation so some don’t use it in day surgery Clonidine: 2ug/kg increased duration of analgesia but no as long as ketamine. With this dose there is increased post op sedation. 1ug/kg has unreliable effect. Opioids: can be divided to long acting (morphine) or short (fentanyl). Morphine 50ug/kg may increase duration of analgesia by upto 24hrs. however commonly produce unpleasant SE (N&V, puritis, urinary retention and possible resp depression). Therefore not for day surgery and only complex urological/orthopaedic procedures Fentanyl 1ug/kg rapidly absorbed into blood stream (therefore unreliable increase to duration of analgesia), and still have some SE, therefore seldom used. In this patient I would consider adding ketamine (ensure preservative free) or clonidine at the doses recommended to increase the duration of analgesia. Especially if being admitted for the night (which is often the case with hernia operation).
(May-2003 Q1) How would you provide post-op analgesia for this infant? Include information on dosage and routes of administration. DANA
Post operative analgesia. Day surgery therefore caudal is an ideal choice Use .2% ropivacaine 1ml/kg (as above reasons) No additives as each can lead to sedation therefore not ideal for day surgery. On top of that paracetamol can be used. Can load with 20mg/kg if needed (PR or IV), then dose of 10-15mg per KG orally. Maximum daily dose of 60mg/24hours so I would suggest 15mg every 6hourly.
NB 90mg/kg/day once over 6 months old… Ibuprofen not recommended until atleast 3 months old (was 6 months). Dose is 5-10mg/kg TDS Codeine phosphate can be used. 0.5mg-1mg/kg 6hourly
(May-2003 Q2) A four week old infant presents for bilateral inguinal herniotomy at a freestanding day surgery unit with a significant paediatric caseload. This infant is to have a general anaesthetic. The parents wish to return to the country that evening. Is the use of a
laryngeal mask an acceptable option for airway management? Justify your answer. JAYNE
This baby is a neonate and neonatal anaesthesia requies special consideration because of the many physiological changes occurring during the adaptation from intrauterine to extrauterine existence. Maturation of the respiratory, circulatory and metabolic regulatory systems takes several weeks after birth and anaesthetic management needs to take this into account. In terms of managing this baby’s airway for this technique I would choose and endotracheal tube. That is not to say however that an LMA may be an acceptable alternative depending on provider experience. The LMA has a role in neonates in resuscitation and difficult airways but I believe in this case of a possibly ex-prem baby (does this baby have bronchopulmonary dysplasia?) who probably weighs less than 5 kg, I would use an ETT. It provides a definitive airway and allows provision of controlled ventilation without the risk of inflating the stomach. The LMA in smaller children and neonates has a higher risk of airway obstruction, requires higher ventilatory pressures, an increased risk of leak on inspiration (increased chance of filling stomach with air and increased risk of aspiration) and more complications ie laryngospasm, upper airway obstruction. There is also an increased work of breathing associated with spontaneous ventilation with this technique
The ETT is not without its own complications however wich as oesophageal or endobronchial intubation, inadvertent extubation (the trachea in neonates is only 4cm), kinking and disconnection. Intubation also increases the work of breathing although you are able to control the ventilation.
Detailed description of how to perform a caudal was not required nor requested. Paracetamol dosage was generally well understood and candidates generally performed
well in this section. I would use multimodal analgesia in this child. I would aim to minimize the amount of opioid analgesia as this child is at risk of post operative apneas. In a 4 week (?possible ex prem) the total daily dose of paracetamol is 60mg/kg in divided doses. I would give a dose of 20mg/kg PR while anaesthetized and write up the remaining 2 doses for administration on the ward on a regular basis. I would also administer a caudal block. I would administer 1ml/kg of 0.25% bupivacaine – according to oxford handbook(what do they use at the MATER??). This dose should give adequate analgesia for 4-8hrs post operatively. The alternative is to administer local infiltration at the completion of the case. I would use 0.125% 7 mls total.
(May-2003 Q3) On what basis would you decided if it is appropriate for this infant to return to the country that evening? JAYNE
Many candidates did not mention the implications of possible pre-term birth for discharge on a day-stay basis. There are several reasons this child having this procedure is not suitable as a day case. As I have previously mentioned this is a neonate who is possibly ex-prem. This baby is at significant risk of post operative apneas and bradycardias after a GA and will need to be monitored overnight with saturation monitoring and apnea alarms. They are at risk of post operative airway/respiratory compromise. Even if the child was not in this high risk group it would not make criteria for a day case patient as they are planning on going back the country and would not be able to make it back to the hospital within an hour.
I would explain this to the parents – the safest option.
(Sep-2001 Q1) You discover a heart murmur, which has not been noted before, in a 3 yo child presenting for elective inguinal hernia repair. How would you assess this child at the
bedside with respect to this murmur, and what findings would prompt you to refer this child to a cardiologist prior to surgery?
68%
Innocent murmurs is up to 72% of school age children. Yet structural heart disease has incidence of 0.5%. Most common innocent murmur is Still’s (ejection systolic murmur with ‘musical quality’). Usually short crescendo-decrecendo, soft grade 1-3 murmur not associated with a thrill. Disappears on standing and reappears on squatting. Pathological murmurs are diastolic, pansystolic, late systolic, very loud murmurs or those with a thrill. It is difficult to unequivocally differentiate between an innocent murmur and one due to a structural lesion. All neonates with midline defects should be assessed for cardiac defects.
Lesions of concern are AS and HOCM, these patients are likely to suffer cardiovascular collapse if GA induced. ECG changes for both include LAD and LVH which can be detected by R in V5 or V6 + S in V1 >5mV (10 large squares). Because it is so difficult to rule out structural lesions antibiotic prophylaxis is indicated for surgery of genitourinary tract, dental, oral or GIT. History: Gestational age at birth. Developmental problems. Growth, feeding. Failure to thrive. Exercise tolerance. SOB/turning blue OE. Chronic cough Recurrent chest infections. Syncope. Chest pains. Medications: diuretics, antiarrhythmics, digoxin. Examination: General appearance ?cyanosis, Downs syndrome. Warmth of peripheries. Clubbing. Respiratory rate and effort. Pulse rate (tachycardia), rhythm and character. Compare right and left and radio-femoral delay and character. BP. Praecordial heave or thrill. Quality of HS and splitting, opening clicks or snaps. Timing of murmur in cardiac cycle. Diastolic or continuous murmurs always abnormal. Length of murmur, abnormal to hear murmur after mid third of systole. Loudness of the murmur usually correlates with severity of cardiac defect. Liver or splenomegally. Investigations: Hb, ECG: LVH suggesting AS or HOCM.
Refer any child with murmur under 1 year old, greater than grade 3 with radiation or thrill.
(Sep-2001 Q2) A cardiological opinion is sought, and echocardiography is advised. The child becomes extremely upset, and the paediatrician and parents ask you to sedate him for the procedure. How will you manage this? 66% This an unplanned anaesthetic procedure, in the context of an unquantified cardiac pathology, in a potentially unfamiliar and remote location. Great care is required to provide sedation safely Preop 1. The approach should be no different from that to any other anaesthetic. 2. Hx and examination of the patient to try to clinically assess likely nature of the cardiac lesion, which would guide anaesthetic technique. Impaired growth, exercise intolerance and cyanosis are indicators of more severe lesions. Cardiologist should also have a good clinical idea of the lesion. Congenital AS or HOCM (family Hx) are high risk lesions. 3. A previously asymptomatic 3yo that is vigorously resisting ECHO is unlikely to have a clinically significant lesion, but a careful approach is still appropriate. 4. Need to explain sedation and procedure to parents and simplified version to child 5. Discuss the role of parental presence during the procedure. Presence of calm parent helps children over 4. Preschool more likely to behave poorly – parent may help or hinder. Parent should be informed that they will be escorted out at point of anaes choosing by staff member. Teenage may not want parents – respect this. 6. Gain familiarity with location, check sedation attemps to date (probably already had some form of failed oral sedation before a request was m ade for anaesthetic assistance) 7. Anaesthesia/Sedation should be provided in an anaesthetically safe environment, with adequate monitoring, trained assistance, anaesthetic equipement and emergency drugs drawn up and available. Resus equipment. This may require moving the patient to another location such as ICU, recovery room or theatre. 8. The patient should be appropriately fasted. 9. EMLA cream can be applied and and IV sited. Intraop 1. Transthoracic ECHO is not a stimulating procedure and minimal titrated sedation is all that would usually be required. 2. The patient only req to be relatively still – avoid unconsciousness. 3. Titrate Midazolam 50ug/kg to effect (readily reversible, titratable, non-painful to inject) 4. If there was suspicion of either AS or HOCM I would recommend transfer to a tertiary institution and in that environment as the anaesthetist I would titrate IV Ketamine (12mg/kg), knowing that this would be associated with more prolonged recovery, possible increase in Hr and risk of N&V. 5. There is usually good access to the airway during TTE. I would provide supplemental O2, but not instrument the airway unless there was a specific clinical indication, such as obstructed resps occurring during sedation. Postop 1. There would need to be an appropriate environment for the child to be recovered in. 2. The procedure is a day case and so considerations for safe D/C would need to be met. Including providing parents with a number to ring with any concerns.
(Sep-2001 Q3) The echocardiogram is reported as normal and the cardiological opinion is that the murmur is physiological and of no concern. Outline and justify your plan for postoperative analgesia following the hernia repair, including after discharge. 81% A multimodal approach can be used for post-op analgesia management starts with pre-op planning. Discussion with parents and informed consent gained. A premed of paracetamol 2030mg/kg can be given. My plan would include: 1. Ilioinguinal and Iliohypogastric nerve blocks. Both derived from L1 in lumbar plexus, iliohypogastric supplies supplies sensation to lower anterior abdominal wall, ilioinguinal nerve traverses inguinal canal to supply skin of groin over scrotum or labia majus. Block performed with short beveled needle inserted 1-2cm medial to ASIS. Pop of external oblique aponeurosis felt and 0.25mls/kg 0.25% Bupivacaine with adrenaline injected. Needle then advanced whilst pressure applied on plunger through internal oblique and when loss of resistance felt second injection of 0.25mls/kg made in space between int oblique and transverses abdomonis into inguinal canal where it can run down a round neck of hernial sac. This block provided equivalent analgesia compared to caudal block and avoids post-operative leg weakness and risk of epidural haemotoma. If necessary supplementation can be provided by skin infiltration by surgeon providing safe doses per kg are observed. 2. Regular paracetamol 20mg/kg Q6H. (Max dose 90mg/kg/day). Paracetamol or an NSAID, act at peripheral sites of injury by inhibiting prostaglandin synthesis and decreasing activation of primary afferent nerve injuries 3. Ibuprofen 8mg/kg Q6H (10mg/kg < 6 months) 4. Oromorph 400mcg/kg for severe breakthrough pain 5. For D/C continue regular paracetamol, with Liquigesic (Paracetamol 120mg/Codeine 5mg/5mls) can be used 0.5mls/kg as alternative ifanalgesia inadequate. Addition of codeine provides increased analgesia from its conversion to morphine. However 9% of the population are poor metabolisers and will not get any benefit from codeine.
(May-2001 Q7) An 8 month old, 10 kg infant presents for laparotomy following failed barium enema reduction of an intussusception. Describe and justify your perioperative fluid
management. LINDA
Pass rate = 58% Intussesception= Invagination of the bowel, usually at the terminal ileum. Usually occurs in infants ( 3-18months old ) 70% of cases are reduced by Barium Enema The child is likely to be dehydrated and may be profoundly shocked. Colloid + Blood may be required. PERI-OPERATIVE FLUID MANAGEMENT: PRE-OP: - Assess level of dehydration: HR, BP, Level of consciousness, Skin turgor, capillary return, wet nappies, fontanelle - If hypovolaemic → NSL 10-20 mg/kg bolus - Calculate fluid deficit and replace 50% over 1 hour and 50% over the next 2 hours. Take into account: - Deficit from a) fasting = 4 ml/kg/h x starvation(h) - Deficit from b) vomiting and diarrhoea. - Estimates of the degree of dehydration is observed from clinical signs. (Correction of 1% dehydration requires 10 ml/kg fluid) - Aim is to restore IV volume in order to maintain CVS stability and organ perfusion, prior to induction - Kidney function is the most important sign of normal hydration, therefore monitoring of urine output is essential. Aim for 1 ml/kg/h INTRA-OP: - Continue with maintenance fluids eg NSL 4 ml/kg/h - Add for ongoing losses from laparotomy eg 6 ml/kg/h - This 10 kg infant will require 100 ml/hour intra-op maintenance - Replace blood with blood/colloid 1:1 or with crystalloid 3:1 POST-OP: - maintenance fluids + compensation for GI losses ( eg NGT aspirate ) and additional losses eg fever. - Monitor urine output and electrolytes
(May-2001 Q8) At the completion of surgery the haemoglobin is measured at 70g/L. Would you transfuse this patient? Justify your answer. LINDA
Pass rate = 28% Acceptable HB at 8 months = 7.8 g/dL The lowest I would go before considering transfusion = 7 g/dL The decision to transfuse should take into account: - Trend in Hb . (Not only one Hb reading.) - Overall health of the child - Hydrations status - Expected further losses It is unlikely that the pt will have ongoing bloodloss after this surgery, so I would way up the risks of transfusion vs the benefits of transfusion: RISKS: - Bacterial contamination - Immunological reactions - GVHD - TRALI - Electrolyte imbalance ( ↓ Na, ↑K, ↓Ca ) - Haemolytic transfusion reactions - Wrong blood given BENEFITS: - Increase delivery of oxygen to the tissues - Increase IV volume and promote organ perfusion I will not transfuse the pt at this time, but I will monitor for bloodloss and hydration status and reassess my decision if the clinical condition of the pt changes. * PRC 5 ml/kg will increase the Hb by 1 g/dL
(May-2001 Q9) In what circumstances would it be reasonable to provide continuous epidural analgesia for postoperative pain relief in this child? LINDA
Pass rate = 63% An epidural in this age group requires : - Experienced operator (not for the occasional paed anaesthetist) - Skilled nurses looking after the pt in the ward - Parental consent It would be reasonable to insert an epidural if a) The above points are present b) The child has OSA, pulm HT, allergy to opiates, cranio-facial abnormalities c) There are no contra-indications: Sepsis, skin infection at site of insertion, INR>1.4, In my experience, the laparotomy wound is small enough to respond well to multimodal analgesia, making epidural analgesia unnecessary - Paracetamol and NSAID’s regularly - Nurse controlled analgesia ( iv opoids ) - Local infiltration by the surgeon.
(Aug-2000 Q9) List the anatomical differences between the neonatal and adult airway. Include the significance of each difference. ANDREW Adult Neonate Significance Larger head, In neutral position less neck • • Smaller • particularly relative size extension req. for optimal relative of occiput airway position. No pillow head size required • • Macroglossia relative to Larger tongue may cause Smaller • mouth size airway obstruction during relative mask vent and ↑ difficulty of tongue size intubation Glossoptosis
•
•
Epiglottis at level of C3
Lower position of larynx C4 6
•
Obligate nose breathers and ↑ nasal passage resistance (until 6 months)
•
•
Epiglottis at C1, longer, stiffer, U-shaped epiglottis forms 45° angle and abuts posterior pharyngeal wall
•
High laryngeal position C3 – 4 and more anterior Funnel shaped larynx
•
•
•
•
narrowest at sub glottic site until 8yoa
•
Cords lie perpendicul ar to long axis of trachea
•
Requires direct elevation of epiglottis by laryngoscope blade placed posteriorly Requires laryngoscopic technique often using ELM and straight blade Use uncuffed ETT and assess for leak to reduce risk of subglottic stenosis
Cricoid ring
Bow-shaped cords
•
↑ Chance of ETT abutting ant. Commissure during blind technique
•
↑ Risk of endobronch or extubation with head turning or overzealous insertion.
•
Requires greater consideration with fixation of the tube
make angle with ant. Commissure
•
Respiratory distress may occur with URTI or choanal atresia. Poor feeding will also result due to difficulty in simultaneously feeding and breathing Allows feeding and breathing simultaneously
Short trachea angled posteriorly
(Apr-2000 Q10) A three year old child is being assessed for insertion of middle ear drainage tubes. On examination you discover that the child has a precordial murmur. What
information would you be seeking in your assessment of this child to decide if the murmur is innocent? DALE (Apr-2000 Q11) If the child is found to have a ventricular septal defect, but is otherwise well, how will this influence your anaesthetic management? DALE (60% pass) DALE
Examiners Comments: Many candidates overstated the physiological significance of an asymptomatic VSD and its impact on anaesthesia. Ventricular Septal Defect (VSD): • • •
•
•
•
Most common congenital heart disease. Effects depend on the size and number of VSDs. A single small VSD is likely to be asymptomatic and result in a small left to right shunt (<1.5:1 pulmonary:systemic blood flow) A moderate single VSD often presents with mild congestive cardiac failure (CCF) and can develop pulmonary hypertension and shunt reversal (>3:1 pulmonary:systemic blood flow) A large VSD results in equal left and right ventricular pressures, presents around 2 months of age with severe CCF Multiple VSDs may require pulmonary artery banding to protect the pulmonary circulation, this results in cyanosis as the child grows and the band tightens, the VSDs often close spontaneously
Anaesthetic Management: • •
•
Discuss the situation with the parents and surgeon An asymptomatic child like this is likely to have a single small VSD o Unlikely to have a significant impact on anaesthesia Special care to prevent air emboli o o Maintain stable haemodynamics Antibiotic prophylaxis not required for this lesion or this surgery according to o current TGA guidelines A larger VSD requires more care with haemodynamics o Haemodynamically stable induction, maintenance and emergence Patients are less able to tolerate high SVR and low PVR o o Avoid pulmonary hypertension Hypoxia Hypercarbia
Acidosis Increased sympathetic output Avoid pulmonary hypotension High fraction inspired oxygen Hypocarbia Maintain intravascular volume but avoid fluid overload Intubate and ventilate to control carbon dioxide and avoid hypoxia Special care to prevent air emboli
o
o o o
Post operatively: • • •
•
Ensure adequate analgesia and not over sedated Routine post operative monitoring in post a naesthesia care unit This well patient with a small asymptomatic VSD should n ot require inpatient care and can be discharged when they meet the discharge criteria A patient with a symptomatic VSD may require HDU or PICU admission post operatively
(Aug99) A nine year old child with spina bifida presenting for a tendon transfer procedure is said to have multiple allergies including latex and antibiotics. How would you decide whether or not the child has latex allergy? DANA Of concern to the anaesthetist are the reactions mediated by IgE antibody to latex protein antigens. These result in mast cell degranulation with the release of mediators such as histamin, tryptase, prostaglandins and leukotrienes 1. history: identifying patients at high risk - occupational exposure to latex (eg health care workers) - multiple operations (especially laparotomies) - repeated bladder catheterization – prevalence in patients with spina bifida reported as 60% - atopy or history of allergy to foods (we all know them, hahaha) - history of anaphpylaxis with no identified agent - women are at higher risk – reason is not clear (maybe more housework with gloves or medically such as pregnancy) all patients should be asked about symptoms after hospital or dental visits or after contact with rubber products such as gloves or balloons. Patients with 1 or more risk factors but no previous symptoms can be managed normally but must be monitored closely for reactions. Patients with symptoms that may be attributed to latex should be regarded as sensitive if no other precipitating factor is identified. If in doubt and surgery is elective, then reschedule and refer f or testing as follows Several techniques are used for the investigation of latex allergy: Serological testing: These in vitro test carry no risk of anaphylaxis. They are, therefore the test of choice if the history reveals a high probability of allergy. The RAST (r adio-allergosorbent test) involves the reaction of patient serum with an antigen polymer complex in the presence of labeled IgE antibody. This allows quantification of the amount of antibody present in the patients serum. However false –ve rate of 25% Skin prick testing: using antigen solution at a variety of dilutions Intradermal testing: with antigen solution Both of these carry the risk of provoking local and systemic reaction and resucitation facilities must be available. They should be performed by a specialist in the field… As none of these methods are infallible a patient with a strongly suggestive history but negative tests should be managed as latex sensitive.
(Aug99) If the child does have latex allergy, describe the precautions that should be taken perioperatively to prevent this child developing a latex reaction? DANA 1. Use of latex free gloves at all times must be ensured during the management of these patients 2. Communicate the problem a.
Patient must be clearly identified, ie marking the case notes, allergy warning wrist band and sings for the patients bed and/or room door. This is important to alert other staff members (eg phlebotomist)
b. Wash hands before contact with patient (to wash off latex) c.
NS staff on ward must ensure that all equipment is latex free and safe to use (eg BP cuffs etc…)
3. PremedicateL with antihistamines +/- corticosteroids have been suggested. They do not prevent reactions but may decrease the severity.
4. Minimise airborne exposure: theatre must be removed of all latex containing equipment. Patient should be 1 st on operating list (least amount of airborne latex allergens). 5. Filters should be new and changed in these patients 6. Signs should be used at theatre entrances to alert all staff of the risk 7. All anaesthetic and surgical equipment must be latex free 8. Monitor as required; anaphylaxis to latex occur 20-60mins after exposure. Therefore for short procedures problems may present in the recovery room or even the ward. Therefore patient must remain in PACU for minimum of 1hour 9. Same post op as pre-op management Be ready and have equipment/drugs available to treat anaphylaxis if occurs
(Aug99) What would you advise the parents regarding the risks that latex allergy adds to the perioperative period? DANA Prevalence in general population is thought to be <1% I don’t know what to write here, any suggestions team??? Tell them that its an added risk but everything will be done to try and avoid latex allergy using the above techniques… If a reaction occurs then we’ll treat it as we can?
THIS IS A SHIT QUESTION SO I’LL TALK ABOUT MANAGEMNET TOO 1. ensure no ongoing exposure to latex 2. 100% oxygen and intubate if needed 3. adrenaline 50-100ug boluses titrated to effect 4. insert art line if 2 anaesthetists available 5. restoration of IV volume with fluids 6. surgery completed as soon as possible 7. once stabilized treat with antihistaimins and corticosteroids (100mg hydrocort) 8. preferably take to HDU/ICU for at least 24hrs 9. Investigate as for anaphylaxis a.
Mast cell tryptase at 1hour and subsequent
10. refer for OPD allergy testing medicalert bracelet
(Apr99) A 4 yo boy weighing 15kg presents for day surgery repair of a left inguinal hernia for which you plan GA and a caudal block. He has no significant past history and is well.
Describe how you would perform a caudal injection for this child. JAYNE (Apr99) Justify your choice of agent(s) for caudal injection for this child. JAYNE (Apr99) If his parents express concern about caudal analgesia, what alternative analgesia options would you offer? Include a brief comment on their particular advantages and disadvantages. JAYNE
There are 3 points of reference: the two sacral cornua and apex of the tip of the fourth sacral spine form a V shape covering the entry point to the caudal space, the sacrococcygeal membrane. A line drawn along the midline of the lateral border of the leg flexed at 90 degrees to the hit, crosses the sacral hiatus in the centre of the back. The sacral hiatus lies at the apex of an equilateral triangle formed by the PSIS A 22 gauge cannula should be used for single shot caudal techniques to reduce the risk of an implanatation dermoid. Direct it at 60 degrees to the skin from the midpoint of the line joining the sacral cornua. A small ‘give’ indicates penetration of the SC membrane. Flatten the cannula slightly then advance. Withdraw the stylet before advancing into the caudal space. Test aspiration should be gentle, vessel walls can collapse giving a false negative result. Resistance on injection or insertion indicates that the cannula is in the wrong place.
Justify your choice of agents for caudal injection in this child. Bupivacaine, Ropivacaine or levo-bupivacaine are commonly used. In order to decide what and how much to use we must consider: The higher the concentration, the longer duration of anaesthesia and higher incidence of motor block Older children are often upset by numb legs The larger the volume of solution the greater the spread of
anaesthetic and the lower the concentration which can be used.
Ropivacaine has a lower incidence of motor block than bupivacaine The clearance of ropivacaine by single shot techniques is reduced in neonates and therefore no improvement in safety profile for this group. But in the case of a 4 year old has a higher safety profile. 0.5ml/kg is adequate for sacral segments, 1ml/kg reliably blocks lumbar and lower thoracic (of 0.2% ropivacaine)
If his parents express concern about caudal analgesia, what alternative analgesia options would you offer? Include comment on their particular advantages and disadvantages. Caudal epidural blockade is remarkably safe: risks are 1/10,000 for serious and 1,40,000 for catastrophic complications. Complications include: subcut, subarachnoid or intravascular injection. Epidural abscess, meningitis and nerve damage are rare. Failure rate is about 2.5%. Indwelling caudal catheters are at increased risk of bacterial contamination due to soiling. Other options include Regional techniques: an inguinal field block (iliohypogastric and ilioinguinal nerves). The advantages of this include the absence of motor block and proprioceptive impairment which may distress the child. It may also delay mobility. However it does provide excellent and reliable analgesia up to 8hrs post operatively. Local infiltration: advantages also include the lack of motor weakness. On the disadvantages side, it is less efficacious and therefore more likely to require adjuvants. It would last a shorter time. Or opioids: although in this case the child is unlikely to have severe
post operative pain. ?whats the recipe at the MATER for a NCA/PCA. He may also access oramorph 0.4mg/kg q4hr prn. Opioids put the child at risk of post operative nausea, respiratory depression, constipation, difficulty assessing the childs pain. Although it does avoid the risks of a regional.
The child must also be given regular paracetamol (up to 90mg/kg/day) and if there are no contraindictions a NSAID such as ibuprofen 10mg/kg orally q8hr.
(Jul98) Compare propofol with sevoflurane as the sole anaesthetic general anaesthetic agent for a 3 yo child requiring insertion of drainage tubes for chronic otitis media. JUSTIN
PROPOFOL; 2,6 – diisopropylphenol. Short acting IV anaesthetic for induction and maintenance ,
of general anaesthesia in adults and children greater than or equal to 1 mth (procedure time < 60 mins in children 1 mth - 3 yrs) Diprivan is contraindicated in; 1. 16 yo or under for sedation during intensive care (propofol infusion syndrome; long-term sedation, but also during propofol anesthesia lasting 5 h. It impairs oxidation of fatty acid chains and inhibits of oxidative phosphorylation in the mitochondria, leading to lactate acidosis and muscular necrosis. Occurs faster in severe diseases in which the patient has been exposed to high catecholamine and cortisol levels.) 2. for monitored conscious sedation for surgical and diagnostic procedures (unpredictable). SEVOFLURANE; fluorinated methyl isopropyl ether, widely used for induction and maintenance of general anaesthesia in paediatrics, including neonates.
(Apr97) A 14yo girl, 130cm tall, with idiopathic scoliosis is scheduled for corrective fixation via a thoracotomy. Controlled hypotension will be used. What are the options available for
providing collapse of the right lung? LINDA
Many children are too small for DLT. A 28 fr DLT should pass in this pt. OPTIONS FOR OLV: a) Standard ETT: - Intentionally intubate a mainstem bronchus - FOB can be passed to confirm placement - Adv: requires no special equipment - Disadv: Failure to achieve adequate seal of bronchus, hypoxaemia due to obstruction of the upper lobe bronchus esp with right mainstem bronchus intubation b) Balloon-Tipped Bronchial Blockers - Adv: Better lung collapse and better operating conditions, than with standard ETT in the bronchus - Disadv: Displacement into trachea → blocking ventilation or prevent collapse of operation side lung, overdistention of balloon can rupture the bronchus, c) Univent tube - It is a standard ETT with a second lumen, containing a tube which can be advanced and serves as a bronchial blocker, when inflated. - Adv: Available in small sizes eg 3.5 and 4.5 mm for kids and because it is firmly attached to the ETT, displacement is less likely. d) DLT - Inserted using the same technique as in adults - Use FOB to confirm position - Left sided DLT are easier to position than right sided DLT - No reports of airway damage in children
Apr97) Two hours into the operation the urine output is measured as 5 ml (in two hours). How would you manage this? LINDA (Apr97) At the time of skin closure her core temperature is 34.1 degrees celcius. How would you manage this? LINDA
(Aug96) A 3 year old child presents with respiratory distress associated with a respiratory tract infection. How would you assess the need for tracheal intubation? ANDREW
Signs of Respiratory Distress in a Child (APLS 4 th Ed)
Best divided into the 3 E’s – Effort / Efficacy / Efficiency Effort – Sounds = Stridor, Wheeze, Grunting (auto PEEP) and Gasping o
Other = Respiratory Rate, flaring of alar nasae, tracheal tug, intercostal / subcostal recession, use of accessory muscles ie SCM
Efficacy – Chest expansion / Abdo excursion o o
Breath sounds / air entry SaO2
Effects – Colour, HR, LOC Pre-terminal signs include a quiet chest, decreasing respiratory effort suggestive of fatigue (particularly with low SaO2 or PaCO2), bubbly noises (secretions not being cleared from the respiratory tract) or depressed conscious level. It is also useful to be aware of the difference in presentation between epiglottitis and croup. Croup is laryngotracheobronchitis. It occurs in younger children (6mths – 5yrs) with peak age2. Has prodrome of coryza +/- mild fever, then progresses to a barking cough and copious secretions +/- inspiratory stridor. Usu cause is parainfluenza but can b e influenza or RSV. Intubation is required in 1% and should follow initial treatment with steroids (Dexamethasone 0.25mg/kg IV , then 2 further doses of 0.125mg/kg Q8/24) and neb adrenaline(0.5mg/kg to max 5mg). Epiglottitis is the bad cousin of croup and is life-threatening. Rapid onset, high fever >39.5, quiet stridor, forward sitting, drooling child with tongue pushed forward that looks septic. HIB is causative. Antibiotic of choice is cefotaxime 0.5mg/kg IV BD. Intubation is required in 60%, some centres intubate all cases. Decision to Intubate is a clinical one based on increasing tachycardia, tachypnoea and chest retraction, or the appearance of cyanosis, exhaustion or confusion. Unless there is respiratory arrest intubation should await transfer to an anaesthetically safe environment, trained staff, checked equipment, monitoring etc.
(Aug96) Describe the facilities you require when you decide to intubate the trachea. ANDREW
Parental Consent Intubate in OT Trained staff Extra pair of hands for cricoid if unfasted ENT surgeon scrubbed and available to perform trache if required Appropriately sized and well fitting face mask Range of ETT and LMA sizes available Paediatric Bronchoscope Oropharyngeal airways Paediatric Stylette Equipment to establish IV access Checked anaestheic machine capable of providing suction and positive pressure for ventilation Sevoflurane vaporizer Self inflating bag as back-up Initial attempt with ETT one size smaller than p redicted Drugs draw up – Sux, Adr, Atr
(Aug96) What are the possible causes of cardiac arrest in this child one hour after intubation? ANDREW
Cardiac arrest is rare in kids and most commonly precipitated by repiratory causes) hypoxia or hypercapnoea. Respiratory problems in this child could include blocking of ETT with secretions, bronchospasm, pneumothorax, occurring either at the time of intubation with subsequent later deterioration or due to endobronchial intubation with subsequent high pressure ventilation. Alternatively the child may have an underlying cardiac defect such as congenital QT syndrome or pulmonary hypertension which may have precipitated the arrest. Other possible causes would include severe sepsis, drug error and anaphylaxis. Oesophageal intubation should have become apparent more quickly than one hour.
