This article highlights the special anatomical and physiological issues, as well as important preoperative, intraoperative, and postoperative care stages. It also covers the fundamentals of pediatric anaesthesia and includes a thorough case report of a 2-year-old undergoing a herniotomy.

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Paediatric anaesthesia has always been a fascinating branch for me because the value and the quality of life you add to these patients is worth doing so. In this article, I would like to share my experience of a 2-year-old male patient electively posted for herniotomy.

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Case report

Clinical examination

1. He is alert, active, and afebrile with a weight of 13 kg and a height of 63 cm.
2. Airway examination is normal with adequate mouth opening.

Investigation

1. Investigation revealed Hb 10.6 g /dl, coagulation profile normal; ECG NSR, viral serology negative. Auscultation was clear.
2. The patient was assessed in the preoperative room and since he was found to be anxious Inj Atropine 0.15 mg iv; Inj Ketamine 10 mg iv was given after securing a 22G iv cannula on the right hand.
3. He was taken into OT and premedicated with; Inj Fentanyl 20 mcg iv; After preoxygenation for 3 - 5 mins, he was induced with Sevoflurane 1-2%, after adequate bag and mask ventilation Inj Atracurium 7mg iv was given and intubated with cuffed 3.5mm ID ET tube (portex) and fixed at 11cm mark after bilateral air entry.
4. Caudal anaesthesia was given with 0.125% Bupivacaine 10 mL before handing it over to the surgeons. A right herniotomy was done. Intraoperative vitals are maintained and monitored.
5. Surgical time was around 1 hour and the intraoperative period uneventful. RL was given around 250 mL and urine output was 30ml. Extubated after spontaneous attempts regained and placed in left lateral position and shifted to SICU.

Discussion

1. The anatomical differences between paediatric and adults make them a distinctive group wherein they differ by infants having larger heads, shorter necks and a larger tongue.
2. Moreover, the glottis inlet is higher at C3-C4 in neonates as compared to C5 in adults and the infant epiglottis is longer and curved anteriorly.
3. Ribs in infants are more horizontal in adults and the breathing is diaphragmatic.
4. The physiological differences start right from the transition to neonatal circulation ( the primary being closure of foramen ovale and ductus arteriosus).
5. The understanding of transitional circulation is essential in the anaesthetic management of congenital cardiac defects (cyanosis and acyanotic)
6. A higher rate of oxygen consumption with decreased functional residual capacity (FRC) leads to oxygen desaturation rapidly if preoxygenation is not adequate.
7. The central nervous system is poorly developed with the parasympathetic system having an edge over the sympathetic system at birth. The immaturity of the blood-brain barrier is also to be noted due to the crossing of depressant drugs like morphine.
8. The extracellular volume at birth almost decreases to 30% within weeks and the maintenance of this volume is important to maintain the body's hemostasis and to balance the electrolytes.
9. The pain pathways are well developed around 24 - 26 weeks of gestational age and the response to noxious stimuli is present. On the contrary, the metabolic pathways are poorly developed at birth.

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Anaesthetic management in paediatric patients

There a the most important points about paediatric patients which would help in the safe and effective conduct of anaesthesia.

As a dictum anaesthetic management can be divided into: 

1. Preoperative (history taking, clinical examination, investigations).
2. Intraoperative ( preparation of OT, airway equipment, drugs, conduct and maintenance of anaesthesia).
3. Postoperative ( pain, temperature and fluid management).

Preoperative assessment should aim at careful history taking, confirmation of fitness for surgery, and a clear explanation of anaesthesia and its related complications with prevention of preoperative anxiety and post-operative pain relief.

Patient attendees play a major role in giving detailed information like birth history, age and weight, congenital defects, and NICU admissions.

Clinical examination

Clinical examination should rule out congenital defects, signs of respiratory distress(subcostal recession), cardiovascular symptoms (associated murmur in congenital and other cardiac lesions) and capillary refill. Airway examination is the most important because these patients present with decreased mouth opening, reduced neck mobility, large tongue, and reduced thyromental distance(retrognathia).

Investigation

1. Essential investigations like CBC, Viral serology, Blood grouping and typing, and Serum electrolytes are to be done .2D Echo is required in neonatal age groups of children less than 2 years and also patients with cardiac defects.
2. Routine investigations(LFT, RFT) are rarely necessary in the paediatric population but are necessary if the patient suffers from associated system defects.
3. Fasting guidelines(recent): Solids - 6 hours before surgery; Milk - Breast milk - 3 hours / bottled milk - 4 hours; Clear liquids - 1 hour before surgery.
4. Paediatric patients should always be taken as the first case in the morning as they are prone to hypoglycemia and dehydration.

Intraoperative management

1. It mainly depends on the preparation of operation theatre(OT) and airway equipment especially in paediatric patients.
2. Preparation of OT starts from keeping the right OT at room temperature (24-28C), choosing the appropriate size laryngoscopic blades (straight blades - Miller and curved blades Mackintosh as per the patient’s size), choosing the appropriate size endotracheal tube (ET tubes) and also whether it is cuffed or not. Supraglottic airways ( I gel, LMA) are also to be kept in cases of emergency.
3. Preparing airway equipment of various sizes( pink to white) is very helpful in encountering a difficult airway patient.
4. Arranging and checking the Jackson Rees circuit or a closed circle system is mandatory before shifting the patient
5. Preparing the correct dosing of drugs is a must as drug errors contribute to the maximum mishaps in anaesthesia practice. Dilution of drugs (Glycopyrollate, Ondanstron, Succinylcholine) in a 5 ml syringe or a 10 ml syringe correlating to the correct dose of the drug according to mg/ kg body weight. Also loading a saline flush after giving the drug should be kept ready.

Conduct of anaesthesia

Placing a shoulder roll, minimising head extension and using a 3-finger technique for intubation in neonates and smaller age requires routine practice.

The following are the processes that prove to be the mainstay in the intraoperative period:

• Reduction of pain and stressor response during intubation
• Choosing the right induction agent [ Sevoflurane(most common) vs Isoflurane ] and technique (Inhalational Vs induction )
• Muscle relaxant [emergency - Succinylcholine/ Rocuronium vs elective(Atracurium]
• Fluid maintenance (Most common - Ringer lactate)
• Prevention of hypoglycemia, hypothermia
• Intraoperative pain management (Paracetamol 20ml/kg)

Calculating urine output according to age group and extubation either in the OT or SICU proves to be the mainstay in the intraoperative period.

Postoperatively after shifting from OT, preventing hypoxia restoring normovolemia, adequate pain management and temperature management, and calculation of fluid input and urine output should be done.

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Anaesthetic emergencies and problems frequently associated with paediatric patients

1. Laryngospasm - often a nightmare for anaesthetists if the adequate depth of anaesthesia is not maintained or inadequate dosage is given at the time of induction. Managed by 100% oxygen and PEEP in most of the cases.
2. Low dose succinylcholine(0.5 -1 mg/kg) and if the second dose is repeated always give atropine 20mcg/kg. Propofol at 0.5 mg/kg is safe and free of cardiovascular events.
3. Vascular access - can present with serious problems in children. Sometimes IV cannula can be placed only after inhalational induction in OT.
4. Respiratory tract infections - Most patients are susceptible to either upper or lower tract infections which need deferment up to 2 and 4 weeks respectively.

Disclaimer- The views and opinions expressed in this article are those of the author and do not necessarily reflect the official policy or position of M3 India.

About the author of this article: Dr Vignesh N, MD (Anaesthesia & Critical Care)  is an Assistant Professor at Meenakshi Medical College and Research Institute in Kanchipuram.