Case

A long time ago, a 3-year-old girl, weighing 14 kg, was scheduled for inguinal hernia repair. Despite rectal premedication with midazolam 14 mg, she was still very active and refused to lie down on the operating table. Parental presence was not yet standard at that time. The decision of the team was to induce anaesthesia in a sitting position by mask using a Bain circuit. Nitrous oxide 60% was administered, followed by sevoflurane 8%.

The charismatic anaesthetist talked to her, suggesting that she could now fall into a good sleep with nice dreams, and indeed she followed his suggestion, closed her eyes and her muscle tone got weaker. About 1 minute later, her respiratory rate increased, she started to move, suddenly opened her eyes and shoved the mask away.

It was now realized that she had never received an anaesthetic gas because the switch on the anaesthesia machine was turned towards ‘circle system’ and not to ‘open system’. Hypnosis was induced only by the suggestive words of the anaesthetist until continuous rebreathing created hypercarbia, made her uncomfortable and finally woke her up.

Discussion

This case of failed anaesthesia induction because of a faulty action by the anaesthetist illustrates the importance of meticulously checking the anaesthesia machine before every case. The author has seen this mistake – selecting the wrong anaesthetic system – in many dozens of cases during his career (Fig. 3.1). When an inhalational induction is planned and no gas arrives at the mask end of the circuit, the consequence will be mild: the child simply does not go to sleep. The situation is much worse when an intravenous induction is performed. The child will then be connected to the wrong circuit and fruitless efforts to ventilate the lungs with the other system will follow. The author is aware of such a case, which led to profound hypoxaemia, the misdiagnosis of bronchospasm and tube exchange before the mistake was recognized. Fortunately, no long-term sequelae occurred. It should be highlighted that failure to measure exhaled CO₂ and sevoflurane concentrations, which was seen in the presented case, should always be considered a warning sign. Admittedly, during induction the most common cause for this phenomenon is insufficient tightness of the face mask, especially when a double mask scavenging system is used, but other possibilities should always be considered as well.

Figure 3.1 An anaesthesia machine allowing the use of a circle system as well as an open system, e.g. a Jackson Rees modification of a T-piece.

There is still debate about the optimal anaesthesia system for induction. A circle system is almost uniformly used for maintenance of anaesthesia in children. Fresh gas use can be minimized to far less than one litre per minute and waste gas scavenging is improved. In addition, modern coaxial tubing systems, even with an integrated capnography sampling tube, have made the system handier and much less bulky. On the other hand, the lightweight open anaesthesia system, e.g. the Jackson Rees modification of the T-piece (Jackson Rees 1950), with no valves, which allows rapid changes in the inspiratory gas composition, is an attractive option for anaesthesia induction in children. Until recently, such systems were widely used by British (Marsh & Mackie 2009) as well as French (Fesseau et al. 2014) paediatric anaesthetists. The compact size and ease of use are probably the major reasons for this preference (Meakin 2007). On the other hand, with the circle system, the novice has a steeper learning curve and unintended high airway pressures with gastric insufflation can more easily be avoided (von Ungern-Sternberg et al. 2007). It is debatable if one or the other system allows better recognition of changes in compliance during manual ventilation; it is likely that the experience of the practitioner is the most important factor in this regard (Schily et al. 2001).

The author is convinced that the trend towards the uniform use of circle systems for induction as well as for maintenance of anaesthesia will continue, mainly because the advantages of using an open system are not really evident, and because modern circle systems allow the continuous measurement of flows and pressures. In addition, the presence of a pressure release valve set at 13 cmH₂O allows avoiding gastric insufflation, and waste gas scavenging diminishes pollution of the theatre. However, even with modern anaesthesia machines, a second outlet in addition to the circle system is desirable in order to be able to administer tailored gas mixtures and not only 100% oxygen, e.g. by nasal cannula or by face mask.

Faulty manipulations by the anaesthetist are a major cause of complications. In order to make the equipment more resilient against wrong manipulations, many institutions, including the author’s, have eliminated the possibility of switching between two anaesthetic circuits. However, many sources for mistakes still remain; a typical one is incorrect connection of the tubing after accidental disconnection. When the expiratory limb is connected to the outlet designated for the bag, massive inflation of the patient’s lungs can occur, with the risk of barotrauma and cardiocirculatory collapse. The author has witnessed several such events during his professional career and wonders why the industry has not yet eliminated this possibility by using different connectors for the inspiratory and expiratory limbs, and especially for the tubing for the bag.

Historically, it was recommended – also to the author when he was a novice – to always smell at the mask before placing it over the face of the child. In the case presented here, the absence of any gas flow would have been noted, and would have prevented this complication. Sniffing anaesthetic gases does not fit well with today’s fear of operating room pollution and the conviction that even traces of anaesthetic gases are harmful (Meier et al. 1995). Nevertheless, ensuring that fresh gas really reaches the child is still a prerequisite for successful anaesthesia induction.

Summary and Recommendations

This case of failed anaesthesia induction because a switch on the anaesthesia machine was in the wrong position emphasizes the importance of a meticulous equipment check.

Real failure of the anaesthesia machine is an extremely rare event; faulty manipulations by the anaesthetist are much more common.

Case

A 9-month-old girl with a Pierre Robin sequence, weighing 8 kg, was scheduled for cleft palate repair. The child was induced by mask with sevoflurane and nitrous oxide. After neuromuscular blockade, the trachea was intubated uneventfully via a laryngeal mask airway (LMA) size 1.5 with the aid of a 2.2 mm bronchoscope and a mounted size 3.5 uncuffed endotracheal tube (ETT). The uncuffed tube was then replaced with a 3.5 RAE Microcuff ETT via a 7F Cook airway exchanger.

Anaesthesia was maintained with sevoflurane, repeated doses of fentanyl, and dexmedetomidine 0.5 µg/kg/h as a co-analgesic agent. At the end of surgery, the child was extubated and noted to have noisy breathing but otherwise no visible signs of airway obstruction. The child was transferred to the intensive care unit, and 20 hours later to the regular ward.

During the second postoperative night, 36 hours after surgery, signs of upper airway obstruction with stridor and the need for supplementary oxygen developed. The child was transferred to the intensive care unit. Despite 100% oxygen by face mask and a jaw thrust manoeuvre to open the airway, oxygen saturation dropped below 80% and an emergency call was sent out. The anaesthetist on call successfully managed the situation by inserting an LMA Supreme size 1.5. Copious secretions were noted. Morphine and midazolam were given to the struggling child, and the team waited for the arrival of the senior paediatric anaesthetist.

He tried a fibreoptic intubation through the correctly positioned LMA Supreme; there was a good view, but as could be expected, intubation was not possible through this type of LMA. Direct laryngoscopy was unsuccessful. The LMA Supreme was replaced with a classic type. The fibreoptic bronchoscope easily passed the cords, but while railroading the ETT severe laryngospasm occurred. Rocuronium 1 mg/kg was given, but ventilation remained unsuccessful. The child now became bradycardic, and chest compressions were started. Atropine and two doses of 10 µg/kg adrenaline were given. Foamy secretions emerging from the LMA impeded the next attempt at fibreoptic intubation. At this point, the senior nurse proposed proceeding to a surgical airway. The senior staff anaesthetist, however, decided to make one further attempt at fibreoptic intubation through the LMA. After repeatedly suctioning the airway, this was finally successful.

The child remained intubated for 9 days, but left the hospital without any long-term sequelae.

Discussion

This is a ‘cannot intubate, cannot ventilate’ situation in a child with a Pierre Robin sequence and, therefore, expected to be difficult to intubate. In the elective situation on the day of surgery, intubation was completely uneventful, primarily using the fibreoptic approach via an LMA (Jöhr & Berger 2004). In the emergency situation in the intensive care unit, upper airway obstruction combined with copious secretions and impaired gas exchange almost led to a fatal outcome. It remained unclear what caused delayed airway obstruction after cleft palate repair, but inflammatory swelling was the most likely explanation.

Insertion of an LMA should be an early step in a ‘cannot intubate, cannot ventilate’ situation (Weiss & Engelhardt 2010). In the presented case, it did not provide a perfect airway, but was sufficient to keep the girl alive. Fibreoptic intubation via an LMA is a standard procedure in children, and every anaesthetist should be familiar with it. Blind intubation through an LMA is nearly always unsuccessful and should not be attempted (Kleine-Brueggeney et al. 2015).

The presented case also illustrates the importance of preventing functional airway obstruction, such as laryngospasm. If a muscle relaxant had been given prior to the first intubation attempt, the near-fatal situation could have been avoided (Weiss & Engelhardt 2012). When everything else fails, a surgical airway should be considered, as suggested by the nurse in this case. Unfortunately, even in animal (Holm-Knudsen et al. 2012) or in human adult cadavers (Heymans et al. 2016) a cannula technique has a high failure rate and cannot be recommended for emergency situations (Duggan et al. 2016). In a neonate or a small infant, a front neck access is a very demanding procedure; the cricothyroid membrane, on the other hand, will be large enough to allow the passage of an ETT, as demonstrated by a serious adverse event described in Case 3.7.

Every practitioner should know the algorithm to manage a ‘cannot intubate, cannot ventilate’ situation by heart. A guideline is like the score for the conductor of an orchestra: you can choose to make variations. In the presented clinical situation, the anaesthetist decided to continue with fibreoptic intubation and not, as proposed by the guideline, to perform a front neck access, because he was convinced he would be able to perform intubation by this technique.

The Pierre Robin sequence is characterized by micrognathia, glossoptosis (Fig. 3.2) and airway obstruction. A cleft palate is common, but does not occur in all patients with a Pierre Robin sequence (Cladis et al. 2014). Typically, neonates present with signs and symptoms of upper airway obstruction and feeding difficulties. In mild cases, airway obstruction can be overcome by positioning the infant in a prone position; in more severe cases, surgical interventions are needed, e.g. glossopexy (Fujii et al. 2015), tracheotomy or mandibular distraction. Airway management is often challenging. It can usually be secured easily with an LMA, whereas laryngoscopy is difficult. A paraglossal approach enhances the view in most patients, and video laryngoscopy has greatly facilitated intubation of these patients. Of course, fibreoptic intubation via an LMA in the anaesthetized child is a very valuable option.

Figure 3.2 A neonate with a Pierre Robin sequence; the tongue has fallen backwards and downwards; it is now behind the cleft (arrows) and obstructs the airway.

Summary and Recommendations

This case of a ‘cannot intubate, cannot ventilate’ situation emphasizes the importance of being familiar with relevant algorithms.

Fibreoptic intubation via an LMA is a standard technique in paediatric anaesthesia which should be taught and practised.

Every guideline has room for some variation. It is like a recipe, which is usually followed, but from which the cook can deviate if the situation justifies it.

Case

A 5-month-old girl, weighing 4.8 kg, was scheduled for oesophageal dilatation under general anaesthesia. Previously, a long gap oesophageal atresia had been repaired elsewhere. There was a functioning gastrostomy. Endotracheal intubation was reported to be difficult.

After premedication with atropine 30 µg/kg via gastrostomy to reduce the abundant oral secretions, anaesthesia was induced by mask. The child was paralysed with mivacurium 0.2 mg/kg, ventilated with the anaesthesia machine, and successfully intubated with a cuffed size 3.0 endotracheal tube (ETT) using fibreoptic guidance and the Frei endoscopy mask. Oesophageal dilatation was begun with a size 14F dilator and increased stepwise. After insertion of a size 22F dilator, ventilation suddenly became impossible even with a peak pressure of 20 cmH₂O. When the dilator was removed, expiratory CO₂ immediately reappeared (Fig. 3.3).

Figure 3.3 (a) A large oesophageal bougie completely obstructs the airway in a small infant, and (b) expiratory CO₂ disappears.

Obviously, despite correct position of the ETT, the presence of a large foreign body in the oesophagus led to a complete obstruction of the tracheal lumen.

Discussion

This case illustrates a typical ‘can intubate, cannot ventilate’ situation, where the ETT is in place but ventilation is still not possible. In this case, the experienced team immediately realized that the large dilator in the oesophagus caused the complete obstruction of the trachea, which was immediately reversed when the instrument was taken out. Airway obstruction is a typical complication of oesophageal dilatation (Gercek et al. 2007) or of transoesophageal echocardiography in infants when large devices are used (Andropoulos et al. 2000). In preterm babies weighing less than 800 g, even a 9F oesophageal stethoscope can completely impede ventilation. The author has also seen severe airway obstruction in a toddler when a piece of apple got stuck in the oesophagus.

The ‘cannot intubate, cannot ventilate’ situation (cf. Case 3.2) is obviously also a dramatic event, but the practitioner can follow an accepted algorithm down to the final step of a surgical airway, when everything else fails (Weiss & Engelhardt 2010). In contrast, if ventilation is impossible after successful intubation (i.e. the ‘can intubate, cannot ventilate’ situation), finding a solution can be much more demanding. Functional problems, such as superficial anaesthesia or insufficient neuromuscular blockade, are common and have to be excluded (Weiss & Engelhardt 2012). The initial steps are clear: the function of the anaesthesia ventilator and a free passage of a suction catheter through the ETT can be rapidly assessed, but then several scenarios are possible and successful treatment requires a correct diagnosis. Knowledge of the patient’s past medical history, physical findings, and often some intuition as well, may be crucial. The differential diagnosis includes but is not limited to compression of the airway, main-stem intubation, position of the tip of the ETT in a fistula, severe bronchospasm, as well as external compression of the lung by tension pneumothorax, gastric distension (Berg et al. 1998) or a large mediastinal mass (Pearson & Tan 2015).

Typically, rather dramatic situations occur during a percutaneous gastrostomy procedure in small children. The gastrostomy tube is pulled down the oesophagus until it exits through the abdominal wall. Usually, a strong resistance is felt when the bulky part of the tube passes the middle portion of the oesophagus right behind the carina, and sometimes completely compresses the airway. An inexperienced anaesthetist might advise the surgeon to interrupt the procedure because ventilation has become impossible. But this will in fact put the patient at an even greater risk, because there is only one solution to this problem: the gastrostomy tube has to be pulled down completely; there is no way back.

Summary and Recommendations

The presented case shows that a large foreign body in the oesophagus can compress the airway and completely impede ventilation.

Managing the ‘can intubate, cannot ventilate’ situation is challenging. While following the steps of an algorithm can be helpful, thereafter, only the correct diagnosis can save the life of the child.

Case

A long time ago, a 2-year-old girl (body weight 12 kg) presented with a lip laceration that required surgical repair. She was premedicated with 10 mg (0.8 mg/kg) of rectal midazolam, an intravenous line was inserted and 20 mg (1.7 mg/kg) of racemic ketamine was given. Standard monitoring was applied.

While the surgeon was cleaning the lip and exploring the field, the anaesthetist filled out the anaesthesia protocol. Suddenly, he heard the oxygen saturation decreasing; when he turned to the patient, he noticed deeply cyanotic lips and tried to ventilate her by mask, which proved to be impossible because of a rigid abdomen. Next, the heart rate decreased and for a full width of the scope there was no QRS complex visible. He immediately advised the nurse to start chest compressions. During cardiac massage, 20 mg (1.7 mg/kg) of succinylcholine was injected, followed by atropine 0.25 mg (0.02 mg/kg). Mask ventilation was then successful, the heart rate picked up, the trachea was intubated with a size 5.0 uncuffed endotracheal tube, and surgery was completed.

The girl made an uneventful recovery and left the hospital 2 hours after surgery.

Discussion

This case illustrates how an inattentive anaesthetist, overlooking the early warning signs (irregular breathing and slight coughing), can be taken aback by laryngospasm. Even though those warning signs are almost always present, this anaesthetist became aware of the situation only when the child was already deeply cyanotic. Earlier intervention with opening up the airway, applying positive airway pressure and inducing muscle relaxation when needed would almost certainly have avoided cardiac arrest. Laryngospasm is still a major cause of cardiac arrest, especially in otherwise healthy children (Morray et al. 2000, Ramamoorthy et al. 2010). The prevention seems to be very simple: the presence of an attentive and skilled anaesthetist.

The pathophysiology of laryngospasm is still poorly understood. In the presence of light planes of anaesthesia, a normally protective airway reflex can turn into an exaggerated reaction potentially leading to organ damage. Laryngospasm is less likely to occur when airway instrumentation, especially endotracheal intubation, is avoided. It is still a matter of debate whether airway removal is better done when the patient is awake or asleep. Extubation or removal of a laryngeal mask airway (LMA) under deep anaesthesia clearly reduces the occurrence of laryngospasm; it is still possible, however, that severe laryngospasm occurs many minutes later. This highlights the fact that children have to be monitored in the recovery area until they are fully awake. The use of propofol is associated with a lower risk of laryngospasm compared to sevoflurane, and desflurane should probably best be avoided. Lidocaine, intravenously or topically, has been shown to protect against the occurrence of laryngospasm (Mihara et al. 2014). It was the author’s practice to administer lidocaine 1–2 mg/kg intravenously in patients at high risk, e.g. before the second trial of extubation after a previous episode of laryngospasm leading to re-intubation.

Respiratory complications, such as laryngospasm, are more common in younger patients (Habre et al. 2017, von Ungern-Sternberg et al. 2010). They occur more frequently with less experienced anaesthetists and when a child is suffering from a current or recent (within 2 weeks of surgery) upper respiratory infection (von Ungern-Sternberg et al. 2010). Infants with respiratory syncytium virus (RSV) infection seem to be at an extremely high risk (Wörner et al. 2009). It was the practice of the author to premedicate patients with an upper respiratory infection and abundant secretions with atropine 30–40 µg/kg orally or rectally, usually 30–40 minutes before the induction of anaesthesia; admittedly, scientific proof supporting this measure is relatively weak (Shaw et al. 2000), but nevertheless it appeared to be very effective.

Ketamine is widely used by anaesthetists and by emergency physicians to provide deep sedation – perhaps better called general anaesthesia because the child is intended to be non-reactive to pain – for skin laceration repair or other minor interventions (Fig. 3.4). Overall, ketamine is considered to be a safe compound, but respiratory complications such as laryngospasm are always a threat (Gloor et al. 2001, Melendez & Bachur 2009). Co-administration of atropine reduces secretions, but not the incidence of respiratory complications (Kye et al. 2012). Ketamine almost guarantees haemodynamic stability, even in vulnerable patients, and an open airway is spontaneously maintained. Intact airway reflexes protect from aspiration, but enhance the occurrence of coughing and laryngospasm. The presence of an attentive physician is obviously mandatory.

Figure 3.4 Laceration of the lip needing a few surgical stitches. A single dose of ketamine and an open airway seems to be an easy approach; however, severe airway complications, such as laryngospasm, can occur.

Summary and Recommendations

This case emphasizes that ketamine sedation needs continuous careful surveillance and a high index of suspicion for potential complications.

Airway obstruction and laryngospasm require immediate intervention, and equipment and drugs must be ready for use: mask, bag and oxygen as well as a muscle relaxant drawn up in a syringe.

Case

A long time ago, a 10-month-old girl was scheduled for a further session of staged resection of a congenital naevus covering large parts of the trunk. She had previously undergone several uneventful anaesthetics. After a halothane induction and neuromuscular paralysis, a size 4.0 uncuffed endotracheal tube (ETT) was inserted. Because of inappropriately high leakage, the decision was made to replace the ETT with a larger one. The size 4.5 ETT only passed with significant resistance. It was nevertheless left in place because the leak with the smaller ETT was thought to make ventilation unreliable given the patient’s prone position with limited access to the head. Cuffed ETTs for infants were not yet routinely available. Recovery was uneventful with the exception of a mild post-extubation stridor, which was treated with moist air.

At the time of the next anaesthetic, at the age of 14 months, a size 4.0 uncuffed ETT provided a perfect fit with no leak. Even at the age of 2 years, only a size 4.0 ETT passed without resistance. At this age, fibreoptic inspection showed moderate subglottic narrowing. The child remained asymptomatic. Later, with increasing growth, larger ETTs could be used but always had to be chosen at least two sizes below the age-based calculated size.

Discussion

This is the only case of subglottic stenosis following short-term intubation encountered by the author during his 40-year career. It is very likely that the forceful passage of the inappropriately sized ETT caused some damage, inflammation and scarring. It is very likely that the use of a correctly sized cuffed ETT (i.e. a size 3.5 for this 10-month-old girl) would have allowed ventilation of the child and avoided the damage. Fortunately, the consequences were mild in this case, with post-extubation stridor as the only symptom and no limitations of her daily life. At that date, when uncuffed tubes were usually used, it was the author’s practice to perform a fibreoptic exam whenever an ETT with a correct fit was two sizes smaller than predicted by age-based formulas, mainly to identify pre-existing pathologies such as a subglottic haemangioma.

There is no doubt that inappropriately large ETTs can cause damage to the subglottic region and must be avoided under all circumstances. Traditional teaching was that a moderate leak should be present at airway pressures exceeding 25 cmH₂O when uncuffed ETTs were used; with a cuffed ETT, a leak should always be present with the non-inflated cuff. When using a cuffed ETT, the cuff should never be positioned at the level of the vocal cords and the cuff has to be inflated with some air to avoid the formation of sharp edges moving forwards and backwards with respiration and causing harm to the laryngeal structures (Dillier et al. 2004). In children, inflation of the cuff to a constant pressure of 20 cmH₂O appears to cause minimal or no damage to the mucosa and is therefore often used (Kutter et al. 2013); in adults, with the main focus being the avoidance of microaspirations, slightly higher pressures, i.e. 20–30 cmH₂O, are recommended (Blot et al. 2014).

Cuffed ETTs are now well established in paediatric anaesthesia, provided that they have an adequate design (Weiss et al. 2004). It has been shown in a large multicentre study that they do no more side effects, e.g. stridor, than uncuffed tubes but have the advantage that changing of the ETT is only rarely needed (Weiss et al. 2009). And, at endoscopy, abnormalities were no more frequent in children who had previously been intubated with a cuffed ETT than in children who had never been intubated before (Weiss et al. 2013). Certain brands of cuffed ETTs, e.g. Microcuff, have the recommended age printed on the package. When the size of the tube is chosen according to these recommendations and the tube is inserted to the recommended depth with the ETT mark at the lower incisors, correct position is achieved in almost all patients (Weiss et al. 2006). This development has greatly simplified the procedure for practitioners who only occasionally treat paediatric patients.

Post-extubation croup can occur, even when a correctly sized tube is used. However, with the frequent use of dexamethasone to prevent postoperative nausea and vomiting or as co-analgesic medication, the author has the impression that post-extubation stridor has become a very rare event. On the other hand, evidence of a clear benefit of dexamethasone for the prevention of post-extubation stridor is scarce (Khemani et al. 2009) and almost absent for its treatment. Most practitioners, however, will rely on the knowledge gained from the treatment of infectious croup, where corticosteroids are widely recommended (Bjornson et al. 2004). In addition, in severe cases, inhalation of adrenaline is used, which usually provides rapid but sometimes short-lived improvement (Bjornson et al. 2013). Although it is widespread, the use of mist or increased humidity of the inspired gas mixture is not evidence-based.

The author has seen several cases of acquired subglottic stenosis; all of these patients had a history of long-term intubation, inappropriately sized ETTs and/or infection. He remembers an infant less than 1 month of age, who was ventilated with high-frequency oscillatory ventilation (HFOV) for over a week because of a severe RSV infection; because of a leak with the uncuffed size 3.5 ETT he was intubated with a size 4.0 uncuffed ETT; after a delay of a few weeks, he presented with a severe subglottic stenosis necessitating surgery (Fig. 3.5).

Figure 3.5 Severe subglottic stenosis after prolonged intubation in a small infant; all three factors came together: a relatively large tube, infection and mechanical damage by movements caused by HFOV (asterisks: vocal cords).

Summary and Recommendations

This case illustrates that even a short-term intubation with an inappropriately large ETT can lead to subglottic damage.

Cuffed ETTs allow successful ventilation without leak and almost eliminate the need for exchanging the ETT because of inappropriate size.

Cuffed ETTs should have an appropriate design, should be positioned with the cuff below the laryngeal structures, and should be inflated at a constant pressure of 20 cmH₂O.

Case

In the early morning, an 11-year-old girl with known asthma and increasing dyspnoea felt unwell, went to the bathroom and collapsed. When her parents found her she was unresponsive and they began chest compressions. A few minutes later, the ambulance crew arrived. They performed tracheal intubation with a size 6.5 cuffed endotracheal tube (ETT) and administered adrenaline. Spontaneous circulation was restored with acceptable blood pressures. However, ventilation was extremely difficult despite the administration of ketamine and rocuronium, and the oxygen saturation remained at 60%.

The child was transferred to the children’s hospital. On arrival, the 21 cm mark of the ETT was found to be at the level of the lips. The tube was pulled out by almost 4 cm. This manoeuvre was followed by a steady rise in oxygen saturation over the next few minutes to values above 90%. In the intensive care unit, asthma treatment included salbutamol by inhalation and intravenous corticosteroids. She steadily improved and could be weaned from the ventilator over the following 2 days.

Discussion

This case illustrates that the correct insertion depth of the ETT is of paramount importance. The correct position of the tip of the endotracheal tube should avoid endobronchial intubation in case of flexion as well as accidental extubation in case of extension of the cervical spine. Especially in the very young, the cervical spine is extremely mobile. It has been shown that the tip of the endotracheal tube can move ± 1 cm in a neonate and ± 2 cm in a 10-year-old child, caused only by movements of the cervical spine (Weiss et al. 2006). The length of the trachea in a term neonate is only 4 cm; for such an infant, the intended position of the tip of the ETT is the midpoint of the trachea, i.e. 2 cm above the carina. In a 5-year-old child it is 3 cm, and in an adolescent 4 cm above the carina. Particularly in the presence of a pneumoperitoneum, the correct ETT position is essential to avoid endobronchial intubation (Böttcher-Haberzeth et al. 2007).

The correct depth of insertion of the ETT can be calculated using age-based formulas. In neonates, the ‘1,2,3 kg – 7,8,9 cm rule’ can be applied (Peterson et al. 2006): the insertion depths for oral intubation are 7, 8 and 9 cm for a 1 kg, 2 kg and 3 kg baby, respectively. For nasotracheal intubation, 20% has to be added. From the age of 1 year, using the formula 12 cm + ½ cm per year results in good estimates for ETT insertion depth for oral intubation. In our patient, an insertion depth of 12 cm + 11/2 cm = 17.5 cm could be expected, and 21 cm was far too deep. In adults, oral ETT insertion depths of 20 cm for women and 22 cm for men may be appropriate (Roberts et al. 1995, Sitzwohl et al. 2010). It is part of good practice to know the approximate ETT insertion depth before we approach the child. Of course, the passage of the ETT between the cords is observed until the markings on the tube are in the correct position. This is ultimately more reliable than the age-based formulas (Weiss et al. 2005). Up to school age, the passage of the tip of the ETT can be palpated very easily in the cervical trachea (Bednarek & Kuhns 1975); a suprasternal position just at the jugulum is optimal (Jain et al. 2004). Deliberate main-stem intubation and auscultation while the tube is withdrawn until bilateral equal breath sounds are heard is nowadays only rarely used (Mariano et al. 2005). Equal breath sounds heard over both lungs do not rule out endobronchial intubation, especially when ETTs with a Murphy eye are used (Verghese et al. 2004). In case of any uncertainty, fibreoptic verification of the correct ETT position is recommended.

Figure 3.6 A chest x-ray of a 2 kg preterm neonate who was intubated in respiratory distress for surfactant administration. The nasotracheal tube was inserted 12 cm instead of the expected 9.6 cm, leading to atelectasis of the left lung and the right upper lobe.

In individuals with healthy lungs even deep endobronchial intubation results in atelectasis formation in the non-ventilated areas, with decreased tidal volumes or higher than usual peak pressures. In the short term, e.g. intraoperatively, life-threatening desaturations rarely occur when higher concentrations of inspired oxygen are used. Problems often arise after surgery, when the extubated child now presents with respiratory failure requiring re-intubation. In contrast, in patients with pre-existing lung disease, such as a severe asthma attack with ventilation/perfusion mismatch, as in this case, profound life-threatening hypoxaemia will develop.

This story of an asthmatic child also shows that even when a diagnosis is known, the initiation of therapy may be delayed unnecessarily in emergency situations. Beta-2-agonists by inhalation are usually highly effective; in addition, intravenous corticosteroids should be given early.

Summary and Recommendations

This case highlights the importance of correct ETT insertion depth. Age-based formulas should be used to estimate the appropriate depth before the patient is approached.

In patients with sick lungs, an endobronchial intubation can cause a ‘can intubate, cannot ventilate’ situation and lead to fatalities.

The timely treatment of the underlying disease, in this case asthma, should not be delayed after the initial steps of resuscitation or on transport.

Case

At 19 weeks of gestation, a fetus presented with a large neck mass, which gradually increased over the following weeks. It obviously impeded fetal swallowing, leading to massive polyhydramnios requiring repeated amniocentesis.

An EXIT (ex utero intrapartum treatment) procedure was proposed but declined by the mother. Therefore, an elective caesarean section was meticulously planned and performed under optimal conditions at 33 weeks of gestation in an operating room at the children’s hospital. In addition to a senior anaesthetist and a senior neonatologist, an ENT and a paediatric surgeon, both fully equipped, were present in the room. The time point was chosen because of poorly controllable polyhydramnios.

After delivery, the baby presented with minimal muscle tone and absent respiratory effort. Without delay, direct laryngoscopy with a Miller blade size 1 was performed. Surprisingly, the vocal cords could easily be visualized and intubation with an endotracheal tube (ETT) size 3.0 with an inserted but non-protruding stylet was attempted. After passing the vocal cords, resistance was encountered. After administering a slight, but not unusual pressure, a sudden give was felt and a yellow watery fluid, followed by blood, flooded the field. Ventilation was attempted but resulted in only minimal movements of the neck mass (Fig. 3.7). Repeated laryngoscopy confirmed that the ETT had passed the vocal cords, but when the ENT specialist performed rigid bronchoscopy, only a dark black region beyond the cords could be seen. After 30 minutes of unsuccessful resuscitation efforts, the baby was declared dead.

Figure 3.7 The large cervical teratoma did not impede direct laryngoscopy, but the insertion of the ETT led to laryngeal perforation.

Post-mortem examination showed a teratoma weighing 340 g. After dissection from the tumour, the trachea appeared normal with no signs of obstruction. However, there was a large, longitudinal 4 mm perforation at the level of the cricothyroid membrane.