|CLINICAL PRACTICE GUIDELINES
|Year : 2022 | Volume
| Issue : 1 | Page : 3-11
Indian Association of Paediatric Anaesthesiologists advisory for paediatric airway management
Shilpa Goyal1, Ankur Sharma1, Pradeep Bhatia1, Indu Mohini Sen2, Gita Nath3, Elsa Varghese4
1 Department of Anaesthesiology and Critical Care, All India Institute of Medical Sciences, Jodhpur, Rajasthan, India
2 Post Graduate Institute of Medical Association and Research, Chandigarh, India
3 Rainbow Children's Hospital, Axon Anaesthesia Associates, Hyderabad, Telangana, India
4 President, Indian Association of Pediatric Anaesthesiologists, Hyderabad, Telangana, India
|Date of Submission||04-Aug-2021|
|Date of Acceptance||16-Aug-2021|
|Date of Web Publication||23-Mar-2022|
Dr. Indu Mohini Sen
Post Graduate Institute of Medical Association and Research, Chandigarh
Source of Support: None, Conflict of Interest: None
The pediatric airway poses a challenge particularly for those who do not anesthetize small children on a regular basis. Anatomical and physiological variations of the airway at different ages have an impact on the decision of which medication to administer with regard to route, dosage, and duration of action as well as the choice of equipment. Knowledge of this helps in the routine management of airway in children. Technological advancements and research have rendered numerous pediatric airway devices available for securing the airway in elective and emergency scenarios. However, their availability alone does not solve all problems. Having the knowledge, the ability to promptly recognize difficulty and to know when to call for help early are key factors for a favorable outcome. This advisory is formulated as a guide for a successful and safe airway management in children for the anesthesiologist involved in the care of pediatric patients.
Keywords: Assessment and management of pediatric airway, equipment for managing pediatric airway, pediatric airway
|How to cite this article:|
Goyal S, Sharma A, Bhatia P, Sen IM, Nath G, Varghese E. Indian Association of Paediatric Anaesthesiologists advisory for paediatric airway management. Indian Anaesth Forum 2022;23:3-11
|How to cite this URL:|
Goyal S, Sharma A, Bhatia P, Sen IM, Nath G, Varghese E. Indian Association of Paediatric Anaesthesiologists advisory for paediatric airway management. Indian Anaesth Forum [serial online] 2022 [cited 2022 Dec 5];23:3-11. Available from: http://www.theiaforum.org/text.asp?2022/23/1/3/340474
| Introduction|| |
The pediatric airway poses a challenge particularly for those who do not anesthetize small children on a regular basis. Anatomical and physiological variations of the airway at different ages have an impact on the decision of which medication to administer with regard to route, dosage, and duration of action as well as the choice of equipment. Knowledge of this helps in the routine management of airway in children. Technological advancements and research have rendered numerous pediatric airway devices available for securing the airway in elective and emergency scenarios. However, their availability alone does not solve all problems. Having the knowledge, the ability to promptly recognize difficulty and to know when to call for help early are key factors for a favorable outcome.
This advisory is formulated as a guide for a successful and safe airway management in children for the anesthesiologist involved in the care of pediatric patients.
Anatomical differences in the pediatric airway, their anesthetic implications and solutions are depicted in [Table 1]. Moreover, [Table 2] is depicting physiological differences in the pediatric airway and their anesthetic implications.
|Table 1: Anatomical differences in the pediatric airway, their anesthetic implications, and solutions|
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|Table 2: Physiological differences in the pediatric airway and their anesthetic implications|
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| Preoperative Airway Assessment|| |
Evaluation of the airway is an integral part of preoperative assessment for every child who undergoes sedation or anesthesia. The following details of history should alert the anesthetist to the possibility of a difficult airway (DA):
- Abnormal cry, hoarseness of voice
- Snoring or sleeping in a semiprone/prone position. Obstructive sleep apnea
- Any known congenital or acquired disorders involving airway.
- Upper respiratory tract infections (URTIs), asthma, bronchitis, pneumonia
- Previous trauma, burns involving the head and neck
- Previous surgery, radiotherapy of head and neck or documentation of DA management.
In addition, a history of full stomach, gastroesophageal reflux, hiatus hernia, gastric outlet obstruction, pyloric stenosis, bowel obstruction, ascites, or abdominal mass causing raised intra-abdominal pressure should be noted.
During airway assessment, anatomical factors predisposing to DA management as well as signs of airway compromise, such as stridor and use of accessory muscles of ventilation should be looked for. The following measurements can help to identify possible anatomical abnormalities.
- Lower lip to chin distance (LCD) <2.2 cm
- Tragus to corner of mouth <7.3 cm
- Thyromental distance (TMD) <4 cm
- Neck circumference >21.4 cm
- Ratio of height to TMD >15.77 cm
- Body mass index (BMI) <12.7 cm.
All the above measures have a good negative predictive value and can be used as screening tools for preoperative assessment. A combination of LCD, TMD, and BMI has been found to be more accurate at predicting difficult laryngoscopic view.,, The Mallampati score can assess the airway only in a cooperative older child. In children, aged 4–8 years, the Mallampati score can be correlated with the Cormack-Lehane scoring assessed during direct laryngoscopy.,
| Availability of Appropriate Airway Equipment|| |
A simple mnemonic to remember the list of drugs and equipment required in DA cart is explained in [Table 3] (SOAPME). [Figure 1] is an example of a portable airway cart. [Table 4] details the appropriate size of equipment recommended for various age groups.
Endotracheal tube size calculations in children >1 year of age in mm ID:
Uncuffed ETT: Cole's formula = (age/4 + 4)
Cuffed ETT: Motoyama formula = (age/4 + 3.5)
Khine formula = (age/4 + 3.0)
Calculation of depth of insertion of ETT at lips or nares in cm:
Neonate: weight in kg + 6 weight in kg + 7
Child: age in years/2 + 12 age in years/2 + 1
| Conduct of Anesthesia|| |
Premedication is recommended to avoid physical struggle which increases the work of breathing and oxygen consumption. It is indicated in anxious children. Nonpharmacological methods include behavior interventions, e.g. showing videos and interactive books, music, and distraction methods (blowing bubbles, toys) or engagement with the anesthetic process itself (choosing and handling the face mask, “blowing up the balloon”) and parental presence at induction of anesthesia. Medications for premedication include midazolam (oral: 0.5–0.75 mg/kg, intranasal [0.3 mg/kg], rectal [0.5 mg/kg], or sublingual [0.3 mg/kg]); dexmedetomidine (intranasal 1–2 μg/kg); ketamine oral (5–8 mg/kg); intramuscular (4–6 mg/kg); or intravenous (1–2 mg/kg).
This maximizes the pulmonary oxygen reserve to prolong the period of safe apnea. An anxious awake child may be unwilling to have a face mask applied. Prior training of the child and using a scented facemask may help improve acceptance. It may help to initially keep the facemask at a distance to insufflate oxygen. Hypoxemia in infants results in bradycardia. The cardiac output being heart rate dependent, when bradycardia occurs, the resulting reduction in cardiac output further aggravates hypoxemia, predisposing to cardiac arrest.
Measures to minimize apnea and desaturation in a child
- Proper planning and adherence to the DA algorithm recommendations are mandatory. Alternative plans B and C should be made in the event of failure of plan A. Extubation should also be planned in advance
- Preoxygenation is the best strategy in an anticipated DA and unanticipated DA management
- Preferably maintain spontaneous ventilation if a DA is anticipated
- Provide apneic oxygenation through a nasal cannula while attempting intubation in an anticipated DA
- A definitive airway should be inserted promptly after cessation of spontaneous or mask ventilation.
Optimum positioning for intubation
To facilitate a good view of the laryngeal inlet and perform endotracheal intubation, the three airway axes, laryngeal, tracheal, and oral, should be maximally aligned. In children <2 years of age, a small shoulder roll placed beneath the shoulders helps align these axes and maintain airway patency. In older children, the head is kept in “sniffing position” with the head and neck slightly extended. In general, for endotracheal intubation, the child's ear lobule and tip of shoulder should be aligned in one horizontal plane.
Choice of induction agent
Inhalational agents, sevoflurane or halothane, are preferred as they are sweet smelling and nonirritant with less potential for laryngospasm compared with isoflurane and desflurane. Sevoflurane has the added advantage of rapid induction and rapid emergence. It is preferred in younger children, especially when no intravenous access is in situ. If nitrous oxide (N2O) is being used to escalate the inhalational induction, its concentration should not exceed 50% to avoid hypoxia. As soon as the child loses consciousness, N2O should be discontinued followed by an oxygen-air mixture and volatile agent.
An intravenous induction is preferred in older children or those having an intravenous cannula in situ preoperatively. Various induction agents such as propofol, etomidate, or thiopentone can be used depending on the clinical profile. However, if a DA is anticipated, these agents should be used with caution
Adequate muscle relaxation is required to facilitate optimum viewing of the larynx and smooth endotracheal intubation.,, They should be administered only after assisted facemask ventilation can be provided. Nondepolarizing muscle relaxants are preferred, except when a rapid sequence induction (RSI) is required. A modified RSI is preferred in children wherein gentle ventilation is performed in infants to maintain oxygenation without the application of cricoid pressure. The external laryngeal maneuver helps bring the laryngeal inlet into view.
The face mask to be extubated in the deeply anesthetized state is that tidal volume should be >5 mL/kg with an age-appropriate respiratory rate. Extubation of a properly evaluated child under deep anesthesia has the advantage of reduced cough and less oxygen desaturations, but there is increased possibility of airway obstruction. Extubation can be done either in supine or lateral position. At the time of extubation, the intubation trolley should be kept ready with all the equipment required for reintubation if needed. Removal of SGA in a child is safest in the lateral position as compared to supine. The risk of airway complications was found to be least when SGA was removed at a deep plane of anesthesia in the lateral position., Postoperatively, oxygenation may be required, necessitating the availability of nasal prongs, face masks, high flow nasal cannulae.
The postanesthesia care unit should have facility for oxygen supplementation, continuous monitoring vital parameters, and pain management. The area should also be equipped to manage any untoward events.
| Commonly Encountered Airway-Related Complications|| |
Laryngospasm, bronchospasm, postintubation croup, and URTI are the complications which can occur perioperatively. There is a risk of postoperative apnea, or desaturation, the recognition and management of these complications has been described in [Table 5]. SGAs should be preferred over ETT in older children with the likelihood of hyper-reactive airways to minimize airway stimulation.
[Table 6] provides a summary and IAPA recommendations for pediatric airway management.
The face mask should be well fitting with minimum leak. The correct size covers the bridge of the nose and the mouth. The operator's thumb and the index finger press the mask on the face with the middle finger on the bony margin of the mandible. The index and little fingers can remain free or hooked under the angle of the mandible. The bony margin of the mandible should be pressed and not the soft tissue to avoid obstructing the airway. External laryngeal manipulation can be done with the operator's little/ring finger for better visualisation of the vocal cords or can be provided by an assistant. Optimum depth of anaesthesia needs to be maintained during mask ventilation.
A relatively large tongue sticks to the palate, leading to difficulty in mask ventilation. An OPA or NPA can open the airway during mask ventilation. The OPA is used in unconscious patients as it stimulates a gag reflex. The appropriate size of OPA is chosen by measuring from the corner of mouth to the angle of mandible. Too large a OPA can obstruct the airway and cause trauma. If it is too small, one can further push the tongue back and fail to relieve obstruction. The appropriate size of NPA is measured from the tip of nose to the tragus. While inserting an NPA, blanching of surrounding skin tissue is suggestive of too large a size. Both devices should be well lubricated prior to insertion.
Supraglottic airway devices (SGAs)
SGAs are useful for both spontaneous and mechanically ventilated children. The second-generation SGAs with a port for the gastric tube are now routinely used for short surgical procedures as an alternative to endotracheal intubation, SGAs are useful rescue airway devices for maintaining oxygenation and anaesthesia in the failed intubation situation under general anaesthesia. SGAs in comparison to ETT have a lower incidence of perioperative adverse respiratory events in terms of laryngospasm or bronchospasm. However, the SGA does not provide a definitive airway therefore, they are not recommended for surgery of long duration in children with airway abnormalities and for transport of patients on ventilator. Intubating LMAs can be used as a conduit for intubation in older children. The maximum cuff pressure recommended for SGA to prevent oropharyngeal leak in children should not exceed 40 cm H2O. These devices have also been used to maintain patency of the airway during extubation in difficult airway scenarios.
The epiglottis is elongated in infants and a straight laryngoscope blade is generally preferred to directly lift up the epiglottis. This provides better visualisation of the laryngeal inlet and insertion of endotracheal tube under vision. Curved laryngoscope blades are used by hooking the tip of the blade in the vallecula and indirectly lifting the epiglottis. Many newer versions including video laryngoscopes have been introduced to facilitate endotracheal intubation. Choice of the specific device depends on availability and personal preferences.
Video laryngoscopes are considered the equipment of choice in anticipated difficult airway when mouth opening is adequate for its insertion. The improved glottic vision increases chances of successful intubation. As the magnified glottic view is visible to the intubator and assistant, further improvement in visualizing the laryngeal inlet can be assessed when optimum external laryngeal pressure is applied. Minimal cervical spine manipulation is required and the device can be simultaneously used along with a fibreoptic bronchoscope (FOB) to improve the chances of successful intubation.
FOB is the technique of choice of anticipated DA in expert hands. Novice users need to practice in simulated conditions and routine intubations. This is the gold standard for confirming adequate positioning of ETT in the trachea.
Uncuffed vs cuffed ETT
An increasing number of paediatric anaesthesiologists prefer cuffed ETTs over the uncuffed ones. A cuffed ETT has the advantage of high first pass success rate, less air leak and gastric insufflation, minimal escape of anaesthetic gases responsible for operation theatre pollution and reduced incidence of post-extubation stridor. The cuff pressure should not exceed 20 cmH20 to avoid damage to the tracheal mucosa and monitoring of cuff pressure is considered mandatory. Microcuff® tubes are especially designed cuffed tubes for children providing an effective sealing at low cuff pressures. The cylindrical shaped polyurethane cuff is placed more distally to avoid endobronchial intubation and damage to the narrower cricoid region and vulnerable mucosal tissues. The ideal depth of insertion for ETT is between the carina and vocal cords. This distance is short in neonates, so the cuff should be passed just below the vocal cords under direct laryngoscopic vision. Presence of bilateral breath sounds should be ensured and confirmed with capnography. Breath sounds should always be rechecked after any change in position of the child to detect any inadvertent migration into the mainstem bronchus or pharynx.
Rapid sequence induction (RSI)
Classical RSI requires application of cricoid pressure and rapid ETT insertion without mask ventilation, using bolus dose of IV induction agent and succinylcholine (1-2 mg/kg). This technique can pose a challenge in the paediatric population. Preoxygenation is difficult as children are not cooperative, and yet prone to rapid fall in oxygen saturation. Application of cricoid pressure is difficult as the cricoid cartilage is small. Inadequate efforts of cricoid pressure application can lead to lateral displacement of the oesophagus thereby increasing chances of pulmonary aspiration.
Succinylcholine is contraindicated in patients prone to malignant hyperthermia, hyperkalaemia and allergy to succinylcholine. Rocuronium is an alternative muscle relaxant for rapid intubation in a dose of 0.9-1.2 mg/kg. Sugammadex is the drug of choice for prompt reversal of its neuromuscular blockade and is available in India. It has an off-label use in paediatrics as it has not been approved by the FDA. Controlled RSI (cRSI) is the preferred technique in children. The following technique is recommended:,
- The child to be kept in 20° head-up position during preoxygenation
- Provide intermittent suctioning of the Ryle's tube in situ, or insert one immediately after intubation.
- Provide adequate hypnosis using propofol or thiopentone followed by adequate muscle relaxation with either a depolarising or non-depolarising muscle relaxant.
- Gentle bag mask ventilation with insufflation pressures <12 cmH20.
- Tracheal intubation in a deep plane of anaesthesia with complete muscle paralysis. Neuromuscular monitoring should be used..
Extubation and Postoperative Care
Extubation is a critical moment during paediatric anaesthesia as children are prone to perioperative respiratory adverse events. Adequate suctioning should be done before planning to extubate. Subglottic suctioning should also be done if the ETT has a subglottic suction port. Small children may not be able to understand voice commands, so observing the breathing patterns and the saturation remains the only alternative. The method of extubation may be chosen according to the patient's clinical profile and the practice of the anaesthesiologist.
In a DA situation, a child should preferable be extubated when awake. 'Awake' extubation is practised when the child has achieved age-appropriate tidal volume and respiratory rate, conjugate gaze, eye opening and adequate muscle power. As the cough reflexes return, the chances of aspiration are reduced. However, the child might be agitated and this can cause surgical site disruption, postoperative bleeding and even desaturation. Hence, extubation of a child can also be done under deep sedation. The pre-requisites for the child to be extubated in the deeply anaesthetised state are that tidal volume should be > 5 mL/kg with an age-appropriate respiratory rate. Extubation of a properly evaluated child under deep anaesthesia has the advantage of reduced cough and less oxygen desaturations, but there is increased possibility of airway obstruction. Extubation can be done either in supine or lateral position. At the time of extubation, the intubation trolley should be kept ready with all the equipment required for reintubation if needed. Removal of SGA in a child is safest in the lateral position as compared to supine. The risk of airway complications was found to be least when SGA was removed at a deep plane of anaesthesia in the lateral position., Post operatively , oxygenation may be required, necessitating the availability of nasal prongs, face masks, high flow nasal canulae.
Post anaesthesia care unit should have facility for oxygen supplementation, continuous monitoring vital parameters and pain management. The area should also be equipped to manage any untoward events.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]