POST EXTUBATION STRIDOR(PES) IN SURGICAL NEONATES AND EX-PRETERM INFANTS

MEDICAL ACADEMY FACULTY OF NURSING

DEPARTMENT OF NURSING AND CARE

SONA MARIA JOSE

POST EXTUBATION STRIDOR(PES) IN SURGICAL NEONATES

AND EX-PRETERM INFANTS

The graduate thesis of the Master‘s degree study programme ”Advanced Nursing Practice” (state code 6211GX008)

Tutor of the graduate thesis

MD, PhD Danguolė Č. Rugytė

TABLE OF CONTENT

4.2. ANATOMY OF INFANT ‘S RESPIRATORY SYSTEM……… 8

4.3. PHYSIOLOGY OF INFANT’S RESPIRATORY SYSTEM………… 11

4.4. SUMARY OF THE MOST IMPORTANT ANATOMICAL AND PHYSIOLOGICAL FEATURES OF THE NEONATE’S AND 4.5. INFANT’S RESPIRATORY SYSTEM………. 12

4.6. ENDOTRACHEAL TUBES (CUFFED AND UNCUFFED)………… 13

4.7. ETIOLOGY AND RISK FACTORS OF PES……… 15

4.8. NURSING RESPONSIBILITY FOR INTUBATION AND EXTUBATION……… 17

4.9. DIAGNOSIS OF PES……… 21

4.10. PREVENTION OF PES……… 21

4.11. TREATMENT AND MANAGEMENT OF PES……… 25

5. ORGANIZATION AND METHODOLOGY OF THE RESEARCH……….. 27

6. RESULTS……… 28

7. DISCUSSION OF THE RESULTS……… …….. 33

8. CONCLUSIONS……… 34

9. PRACTICAL RECOMMENDATIONSTO PREVENT PES IN NEONATES… 35 10. LIST OF LITERATURESOURCES……… 36

11. PUBLICATION………. 40

12. ANNEXES………. 41

. ETHICAL APPROVAL

INDIVIDUAL PLAN OF PREPARATION OF THE GRADUATEMASTER THESIS DECLARATION OF THE AUTHOR’S CONTRIBUTION AND ACADEMIC HONESTY EVALUATION BY THE SUPERVISOR OF THE GRADUATE MASTER THESIS

1. ABSTRACT

Sona Maria Jose.Post extubation stridor (PES) in surgical neonates and ex-preterm infants. The graduate Master‘s thesis. The tutor – MD, PhD Danguolė Č. Rugytė. Lithuanian University of Health Sciences, Medical Academy, the Faculty of Nursing, Department of Nursing and care. Kaunas, 2019; 40 pages.

Post extubation stridor (PES) is a complication of intubation especially in children due to their anatomically smaller upper airway. According to the clinical experience PES is common in neonates following general surgery in LUHS.Therefore the aim and objectives of the presentstudywere :1.To find out the incidence of PES.2. To analyse treatment strategies of PES. 3. To analyse the possible causes of PES. Methodology: Case files of neonates and ex-preterm infants who had undergone general surgery with tracheal intubation and mechanical ventilation after surgery over the period of 2008 – 2010 years were reviewed retrospectively for the demographic data, duration of mechanical ventilation and the incidence of documented symptom “postextubation stridor”. Case files with a documented PES were additionally analysed and data on ET tube size, treatment measures initiated after the evidence of PES, duration of treatment and outcome of PES collected. Statistical analysis was performed with STATA 7 software with the methods for nominal and abnormally distributed data. Results are presented as number of cases (%) and median (min-max).Results: 80 (male 44/female 36) case files were reviewed. Sixty-six patients (82.5%) were extubated within 30 (0-384) h after surgery, while 14 (17.5%) had never been extubated. PES was identified in 10/66 (15.2%) of extubated patients. Five patients (5/66 (7.6%)) were treated with the inhalation of adrenalin in normal saline (1:10), the rest were treated with the inhalation of normal saline. The duration of treatment ranged from 1 to 24 h and there were no long term consequences. There was no difference in demographic variables or the duration of mechanical ventilation in patients with and without PES.Conclusions :1.Post extubation stridor is a frequent complication in neonates and ex-preterm infants after surgery (15.2%). 2. Treatment of PES depended on the severity of stridor and consisted of inhalation of normal saline or adrenaline in normal saline. 3. Based on this retrospective analysis no definitive causes of postextubation stridor could be identified, therefore larger studies, focusing on possible risk factors are required.

2. ABBREVIATIONS

American Society of Anesthesiology ASA

Endotracheal tube ET

Hour h

Internal diameter ID

Kilogram kg

Laryngeal Airway Column Width Difference LACWD

Microgram µg

Milligram mg

Millimeter mm

Neonatal intensive care unit NICU

Oxygen O2

Postextubation stridor PES

3.INTRODUCTION

Aaccording to the registry of the Hygiene Institute of Lithuania around 30 000 live birth are registered every year: for example, the statistics of live birth in 2010 was: Kaunas -17 929, Vilnius - 12 702. Perinatal center of the Lithuanian University of Health Sciences (LUHS) is one of the two Perinatal Centers in Lithuania. Around 200 newborns are operated in the two Perinatal Centers of Lithuania every year (1).

Previous study showed thatpost extubation stridor (PES) is the most frequent complication in neonates following general surgery in LUHS and Children’s Hospital of Vilnius University (Figure 1) (2).

Figure 1. The incidence of anesthesia complications in neonates, undergoing general surgery according to Žilevičius R., Rugytė D. and Daugelavičius V (2)

Post extubation stridor is a complication of intubation especially in children due to their anatomically smaller upper airway. PES is very common in Neonatal Intensive Care Unit (NICU).The most frequent cause of PES is an ischaemic damage to laryngeal mucosa by

inappropriate size edotracheal tube (ET), leading to edema or swelling when trachea is extubated. Children undergoing surgery with tracheal intubation are also at risk of PES (3, 4, 5). Between the other risk factors for PES is poor clearance of secretions or vocal cord palsy. Secretions

accumulated in the upper trachea may block the airway. Vocal cord palsy may occur during long

0 5 10 15 20 25 30 Complications of anesthesia

Both respiratory (non PES) and cardiovascular complications

Cardiovascular complications

Respiratory (non PES) complications

Post extubation

stridor (PES)

duration of mechanical ventilation and tracheal intubation due to the mechanical laryngeal nerve injury and may lead to failed extubation of trachea. The cases of vocal cord palsy were observed after cardio-thoracic surgery (4, 6). PES must be treated properly, otherwise it may lead to prolonged duration of NICU/hospital stay.

Pathologically, post-extubation stridor is associated with nonspecificchanges such as laryngeal edema, inflammation, formation of granulations and ulcerations. Although most cases resolve spontaneously with correct medical treatment, a minority develop more serious

complications, including subglottic or tracheal stenosis, necrotisingtracheobronchitis or tracheal perforation.

Nursing is an extremely important part of patient care, therefore the causes of PES must be acknowledged and preventive measures used while risk factors, also nursery-related, avoided. Therefore, the study was carried out to get better insight into the frequency, causes, treatment and consequencies of PES in LUHS.

Aim

To analyze the occurrence of PES in neonates and ex-preterm infants who had undergone general surgery under general anesthesia with tracheal intubation.

Objectives

1.To find out the incidence of PES 2. To analyze treatment strategies of PES 3. To analyze the possible causes of PES

4.REVIEW OF LITERATURE

Definition of PES

According to the 24th edition of the Dorland’s Pocket Medical Dictionary stridor is explained as “ a harsh, high-pitched respiratory sound”...” laryngeal s., that due to laryngeal obstruction”... (7).

Post extubation stridor is the complication of intubation, usually longer than 24 h, but sometimes it occurs after a shorter period (3). It may result from poor clearance of secreations, brain stem dysfunction,vocal cord paralysis,vocal cord granuloma , or subglotic stenosis (5, 8, 9). Age, weight,length of mechanical ventilation, size of oro-tracheal cannula, presence of a cuffed endotracheal tube (ET) - all these are the factors influence the development of PES (6). Post extubation stridor is related with increased morbidity including long period of hospital stay and the risk of reintubation, airway injuries, and hospital acquired infection (5). Mechanical ventilation in the operating room and intensive care unit is related with the possible development of glottic or subglottic edema. It will lead to the development of stridor upon extubation. In children the narrowest part of the airway is at the level of the cricoid cartilage compared to the level of vocal cords in adults. For this reason endotracheal tubes may cause the laryngeal injury in infants and children most often at the level of the cricoid cartilage (10,11).

Anatomy of infants’respiratory system

Before tracheal intubation, it is mandatory to meticulously assess all aspects of the airway to develop detailed and flexible plans for intubating the trachea, management of airway during intubation and mechanical lung ventilation and postoperative recovery (12).

During spontaneous ventilation, the upper airway is exposed to potentially collapsing negative pressure during inspiration, but the pharynx is kept open by the upper airway muscules. The pharynx is prone to collapse because negative pressure pulls the tongue against the pharynx. The genioglossus is the principal muscle that dilates the pharynx, and it serves to keep the upper airway patent. This muscle receives feedback from the central nervous system via the hypoglossal nerve and from the lower airway via the vagus nerve.

The most of sedative agents and anesthetics depress activity of the upper airway and therefore predisposes t oropharyngeal obstruction, especially in newborns and young infants, whose upper airways and chest wall are easily compressible.The contribution of the tongue to airway obstruction is exaggerated in infants because the tongue is large relative to the total volume of the mouth. Neonates and infants with smaller upper airways secondary to craniofacial anomalies, weakness as a result of neuromuscular or central nervous system disorders, impingemenet on the airway secondary to tumors or hemangiomas, or dysfunction of the tracheobronchial tree because of the upper respiratory infection are especially prone to pharyngeal obstruction by the tongue.

Head position is important to maintain upper airway patency during sedation or anesthesia before tracheal intubation. Flexing the infant’s head may cause the upper airway to collapse more readily. This is particularly important during induction of anesthesia or sedation in neonates and infants with abnormal upper airways. The head and occiput are relatively larger than the rest of the body, which requires the neck to be flexed on the chest if the face is in a midline sagittal plane; this is why a newborn lies with the face turned to one side. However, if the child's head is put into a good "sniffing" position (neck flexed on chest and head extended on neck) by extending the head on the neck, the exposure of the larynx will be facilitated. Still, during and after intubation, the large occiput causes the head to be unstable, with a propensity to roll to one side or another; this can be remedied by placing the occiput inside a doughnut-shaped stabilizing sponge pillow (13). There are other differences in the anatomy of the newborn airway compared with that of the adult airway. The narrowest portion of the infant's airway is the subglottic area at the level of the cricoid cartilage, compared to the level of vocal cords in adults.

In addition, the small soft airways of the neonates (especially premature neonates) are more compressible if the neck is flexed. Extending and keeping the neck in neutral position while applying positive airway pressure during ventilation with a bag and facemask is important, particularly during induction of sedation and anesthesia.

In a normal newborn the neck is short in comparison to the adult. The larynx of the infant is higher in the neck (C3-4) than in adults (C4-5). The larynx-to-carina distance is only 4 cm in the infant, and consequently great care must be taken to pass the endotracheal tube beyond the vocal cords by only 1.5 to 2.0 cm in order to avoid bronchial cannulation. An infant’s epiglottis is large, but it is narrow and short. It projects cephalad at approximately 45 degree from the anterior wall of the larynx, and it is relatively stiffer and longer than an adult epiglottis. Although this makes the epiglottis easier to visualize, it also makes the epiglottis more difficult to displace so that the laryngeal aperture may be visualized (Figure 2). Because of these anatomic features a straight

laryngoscope blade may allow the larynx of a normal infant to be visualized more easily. For these reasons a Miller blade is preferable to a Mackintosh blade for intubation of infants (12, 13)

Figure 2.The view of the laryngeal structures of the infant – epiglottis and vocal cords, with narrowed subglottic space seen beyond the vocal cords. Epiglottis is of different

shape (U-shaped) compared to adults (photo by D.Rugyte).

When laryngeal anatomy is distorted by craniofacial anomalies (micrognathia or midface hypoplasia), direct visualation of the larynx may be impossible, and alternative methods of securing the airway should be available.

An infant’s vocal cords are slanted such that the posterior commissure is more cephalad than the anterior commissure. This arrangement may predispose the anterior sublaryngeal airway to trauma from endotracheal tube. The subglottic area is prone to traumatic injury from an ET because of the narrowest portion of the infant’s larynx is at the cricoids cartilage. In adults, the narrowest portion is the glottic rim. Thus the ET that easily passes through the vocal cords of an infant or child may fit snygly in the subglottis and cause subglottic edema and symptoms of increased airway resistance after tracheal extubation, or postextubation stridor. This increased resistance is usually reversible, but subglottic stenosis may develop after prolonged tracheal intubation with an oversized ET.

Physiology of infant’s respiratory system

Alveolydvelop mainly after birth and increase from 20 million terminal air sacs in a newborn to 300 million alveoli at 18 months of age. In general, extrauterine viability is first likely after 26 weeks when the respiratory saccules have developed and vascularization by capillaries has occurred (12). Breathing movements begin in utero and are characteristically rapid" irregular, and episodic during late pregnancy. Normally, they are present for 30-60% of the time and are subject to diurnal variation. Fetal breathing movements may help to develop the respiratory muscles, and monitoring of these movements may provide information on fetal health. The fetal lung is filled with fluid, which is moved by this respiratory activity. After 26-28 weeks of gestation, production of surface-active substances (surfactant) is established in the type II pneumocytes. Surfactant is secreted into the lung and can be detected in amniotic fluid samples; thus providing a diagnostic index of lung maturity and hence neonatal prognosis. Passage of the fetus through the birth canal compresses the thorax, forcing fluid from the lungs via the nose and mouth. On delivery, this compression is relieved and some air is sucked into the lungs. The first breath is initiated by peripheral (cold, touch, etc.) and biochemical (respiratory and metabolic acidosis) stimuli. The first few spontaneous breaths are characterized by high transpulmonary pressures (over 50 cm H2O) and establish the functional residual capacity (FRC) of the neonate’s lungs. Remaining lung fluid is removed within hours by the pulmonary lymphatics and blood vessels. The stability of the alveolar matrix in the newborn is dependent on the presence of adequate amounts of surfactant, which may be deficient in the premature infant (14). Pulmonary surfactant effects dramatic changes in lung mechanics, including distensibility and end-expiratory volume stability. The development of respiratory distress syndrome of the newborn correlates with insufficient (premature newborn) or delayed (infants of diabetic mothers) synthesis of surfactant (12). Lack of surfactant leads to collapse of alveoli, maldistribution of ventilation, impaired gas exchange, decreased compliance, and increased work of breathing. Not surprisingly, pneumothorax occurs more commonly during the neonatal period than at any other age (14). Chronic lung disease also persists as a common problem in approximately

20% of premature infants as a result of the complex interplay of many factors in addition to surfactant during normal growth and development of the lungs. Supportive care of a premature infant commonly includes oxygen and positive pressure ventilation, and infections are inevitable (12).

The compliant rib cage of a newborn produces a mechanical disadvantage to effective ventilation. The negative intrapleural pressure produced by normal inspiratory efforts tends to collapse the cartilaginous, compliant chest of an infant, especially premature newborn, which causes paradoxical chest wall motion and limits airflow during inspiration. The circular

configuration of the rib cage (ellipsoid in adults) and the horizontal angle of insertion of the diaphragm (obligue in adults) cause distortion of the newborn’s rib cage and inefficient diaphragmatic contraction (12).

An adult diaphragm contains 55% type I fibers (fatigue-resistant, slow-twitching, highly oxidative fibers). Whereas the diaphragm of a full-term neonate has 25% and that of a preterm neonate has 10%. A lower proportion of type I fibers predisposes these primary respiratory muscles to fatigue. The intercostals muscles show a similar developmental patern (12).

Summary of the most important anatomical and physiological features of

the neonate’s and infant’s respiratory system

In summary, these are major features to be remembered before manipulating the neonate’s or infant’s airways (12, 13, 14):

1. The head is relatively large and the neck is short.

2. The tongue is relatively large and readily blocks the pharynx during anesthesia and sedation; hence, an oropharyngeal airway may be required. The large largetounge may also hamper attempts to visualize the glottis at laryngoscopy.

3. The nasal passages are narrow and are readily blocked by secretions or edema. Nasal obstruction may cause serious problems because many infants will not immediately switch to mouth-breathing. Neonates were previously described as "obligate nose-breathers," but whether this is always true has recently been questioned. It is certain that many infants still not easily convert to mouth-breathing if the nasal passages are obstructed.

4. The larynx is situated more cephalad (C4) and anteriorly, and its long axis is directed inferiorly and anteriorly.

5. The airway is narrowest at the level of the cricoid cartilage just below the vocal cords. Here it is lined with ciliated epitheIium that is loosely bound to areolar tissue. Trauma to these tissues results in edema, which reduces the lumen and greatly increases resistance to airflow (stridor). Even a small amount of circumferential edema significantly encroaches on the small area of the infant airway, raising resistance markedly.

6. The epiglottis is relatively long and stiff. It is U-shaped and projects posteriorly at an angle of45o above the glottis. It must be elevated by the tip ofa laryngoscope before the glottis can be seen; hence, the use of a straight-blade laryngoscope is recommended.

7. 7. The trachea is short (approximately 5 cm); therefore, precise placement and firm fixation ofendotracheal tubes are essential. The tracheal cartilages are soft and can easily be

compressed by the physician's fingerswhile holding a mask or can be collapsed by vigorous attempts of the patient to breathe against an obstructed airway.

8. Because the ribs are almost horizontal, ventilation is primarly diaphragmatic. The abdominal viscera are bulky and can readily hamper diaphragmatic excursion, especially if the gastrointestinal tract is distended.

Endotracheal Tubes (Cuffed or Uncuffed Tubes)

All endotracheal tubes have a preformed curve which conforms to the child’s anatomy of the airway, aiding insertion and preventing kinking whilst in situ. The tube is oval in cross section but the distal end may be cut at an oblique angle so that the aperture opens on the left side. This facilitates visualisation of the tip of tube as it passes through the cords when introduced with the right hand by the physician. There can be a hole at the bevelled end (Murphy’s eye) which allows an alternative route for gas flow should the bevelled end become obstructed by blood, mucus or the tracheal wall (13). It is also believed that it allows ventilation to the other lung should inadvertent main stem intubation occur. Tubes have markings from top to bottom in cm and a radio-opague longitudinal line. Sizes are in millimeters (mm) of internal diameter. Uncuffed endotracheal (Figure 3) tubes have traditionally been used in infants / children < 8 years because their airway is funnel shaped and narrowest at the cricord cartilage which acts as a physiological seal compared to a cylinder airway in the older child / adult. However there is evidence showing that using a cuffed tube (Figure 3) on all age groups has no increased adverse effects and also reduces multiple intubations and reduces cost (13). There should be an audible leak when a pressure of 20 cm of water is applied to the breathing circuit after intubation with an uncuffed tube and expired CO2 must be identified (15).

There are several suggestions how to calculate the accurate depth placement of ET tube in the trachea - the distance from teeth or upper gum to tracheal midpoint (15):

( height [cm] x0.1) + 5 cm or (weight [kg] x 0.2) + 12 cm. In neonates, the distance from the upper gum to the tracheal midpoint is shown in Table 1.

Table 1.the distance from the upper gum to the tracheal midpoint in neonates

1 kg in weight 7cm

2 kg in weight 8cm

3 kg in weight 9cm

4 kg in weight 10cm

Yet, one of the most recent recommendations for the depth of insertion of the ET tubes in neonates, infants and children is the following (12):

Preterm neonate 6-8 cm Term neonate 9-10 cm 6 months 10 cm 1-2 years 10-11 cm 3-4 years 12-13 cm 5-6 years 14-15 cm 10 years 16-17 cm

A practical method for accurate depth placement of the tube, applicable to oral and nasal intubation in pediatric patients of any size, has been described. The endotracheal tube is deliberately advanced until it enters a mainstem bronchus, invariably on the right, as confirmed by auscultation . While auscultating in the contralateral axilla, the tube is slowly retracted until breath sounds return .Stop retraction and note the depth at the lips or teeth .Now retract the tube 2 more cm and secure it firmly. The distal end of the tube is now safely located 2 cm above the carina. For children > 6yr, this distance should be 3 cm. Note that the length of the trachea from larynx to carina is 4 cm in the newborn and increase to 6 cm by years of age (15).

In LUHS a practical approach to the depth of insertion of ET tubes in neonates is used: patient’s weight (kg) + 6 = depth (cm).

Materials of ET tubes.Endotracheal tubes are available in several materials. Polyvinyl chloride is the most widely used although red rubber remains in use and silicons rubber has become increasingly popular.The finding in the 1960s that certain materials were toxic to tracheal mucosa, producing an inflammatory response, led to testing to evaluate toxicity. The most common procedure requires implanting a silver of ET tube material into the paravertebral muscle of a rabbit and examining for tissue toxicity, both macroscopically in 3 or 7 days. If there is no inflammatory response, tubes made of that material can be considered safe.

Figure 3. Cuffed and uncuffed endotracheal tubes used for tracheal intubation

Etiology and risk factors of PES

The newborn airway is of a smaller calibre than that of a child or adult. It has less well developed cartilaginous structures, which contribute to flaccidity of the airway. Both of these characteristics make the newborn airway more vulnerable to the effects of either extrinsic compression or intrinsic obstruction.Most often post extubation stridor can be caused by subglottic stenosis, laryngeal edema, mucosal ulceration due to direct mechanical injury of the larynx and the vocal cords as the consequence of the ET tube or ET cuff pressure. It is recommended that ET cuff pressure did not exceed the hydrostatic capillary pressure of laryngeal and tracheal mucosa – 25 mm Hg. Using cuff pressure measurement and keeping it within recommended limits may help to prevent laryngeal or tracheal damage (16). During the first 24 hours after extubation PES may develop due to laryngospasm and/or laryngeal or subglothicedema, which may occur at the level of cricoid ring of the child’s airway. Larynx at the level of the cricoid ring is the narrowest part of the pediatric airway, therefore is the most susceptible to trauma and obstruction after endotracheal intubation (11,17).

Pressure on the posterior larynx by the ET is the main cause of post extubation stridor in neonates and children. However, some other factors may contribute to the development of PES too. Poor clearance of secretions leads to the airway obstruction, while suctioning of secretions may cause trauma and infection of the airway, both potentially resulting in PES (18, 19).

Irritation of the larynx or trachea by the dry air or irritant exogenous substances can be associated with the development of tissue edema and PES. Any irritant stimulus, such as dryness of

inhaled gas, allergy to laryngeal sprays, or chemical irritation from rubber or ethylene oxide-sterilized tubes can initiate an inflammatory response, producing mucosal edema in the larynx or trachea. The edema reduces the lumen and thereby increases airway resistance (20).

Endotracheal intubation technique is an important risk factor in the development of PES in children due to the easily vulnerable airways. Children below 24 months of age would be at the increased risk of PES due to the smaller upper airways. Very high risk of postexubation stridor development is in children under 12 months of age and weight below 10 kg (6). Difficult tracheal intubation generally occurs when facial or oral pathology prevents visualization of the larynx or when the larynx is easily visualized by direct laryngoscopy (Figure 4) but a lesion in the supraglottic, glottis or subglottic region interferes with insertion of ET. Circumstances that may result in difficult intubation may also be categorized by anatomic location or by etiology (congenital, inflammatory, traumatic, metabolic, or neoplastic) (12).

Figure 4. Direct laryngoscopy

When the past medical hystory previous difficult airway management and tracheal intubation, it is recommended that a physician, experienced in performing pediatric bronchoscopy be present during initial airway management. Fiberoptic airway endoscopy with or without the aid of laryngeal mask airway may be indicated for securing a difficult airway. Before intubation procedure, the patient’s parents should be informed of the risk. In some situations, performing a controlled

tracheostomy may be less traumatic than persisting with multiple attempts at direct laryngoscopy (12).

Thus traumatic or repeated intubations may result in the development of PES after extubation. The outcome of PES may vary from benign, short-term breathing abnormality to severe acquired subglottic stenosis. Acquired subglottic stenosis is due to infection or trauma due to endotracheal intubation. It is mostly observed in low birth weight infants who require prolonged intubation and mechanical ventilation (21). Acquired subglotic stenosis may lead to long term morbidity.

In summary, the most common risk factors of PES are: incorrect size of endotracheal tube

laryngeal or tracheal irritation upper airway infection

traumatic orrepeated intubation prolonged intubation period tooaggressive tracheal aspiration

Nursing responsibility for intubation and extubation

Indications for intubation and/or ventilation:

• Maintenance of patent airway / upper airway obstruction • Worsening Respiratory Distress / Respiratory Failure • Prolonged apnoea

• Inadequate ventilation

• Worsening hypoxia, despite oxygen therapy

• Elective Intubation, i.e. following neonatal surgery, cardiac surgery or prior to general anaesthesia

• Trauma, i.e. facial injuries

• Neurological, i.e. raised intracranial pressure (ICP), deteriorating Glasgow Coma Scale (GCS), i.e. < 8 with no gag reflex

• Inhalation burns

• Cardiac monitor

• Oxygen saturation monitor • Blood pressure monitor

• Bag-mask (appropriate size) ventilation and oxygen source ready • Oro or naso pharyngeal airways of appropriate size

• Appropriate size ET tubes, one 0.5mm smaller and 0.5mm larger (internal diameter measurement mm ET tube)

• Appropriate sized laryngoscope

Types of blades for intubation of trachea: • Preterm Infant – Size 0

• Infants - Size 0-1

• Small Child - Size 1 or 2

Figure 5. Neonate and infant size straight laryngoscope blades

Curved blade(Mackintosh): • Infant/ Child (<12 kg) Size 1 • Child (< 22 kg) Size 2 • Large Child (< 30 kg) Size 3 • Suction devise

• Magill’s forceps of appropriate size • Gauzes

• Nasogastric tube

• Material or devises to properly fix the ET

• Ventilator with appropriate settings checked by anaesthetist/NICU physicians • Stethoscope

• Scissors

• Trolley or clear surface for equipment Equipment for extubation:

• Suction catheter

• Oro or naso pharyngeal airways of appropriate size • Bag and mask ventilation ready

• Oxygen cannula / tube • Humidifier

• Fixing tape

• Plaster removal swabs • Tegaderm dressing • Scissors

• 5 / 10 ml syringe • Stethoscope

• Emergency intubation trolley nearby • Nebuliser circuit and mask

• Racemic Epinephrine • Non-sterile gloves

Other:

The neonate may require maintenance fluids whilst nil by mouth. Wean sedation as appropriate i.e. morphine infusion decreased to maximum 20 µg/ kg/ hour. Ensure suction and oxygen equipment are functioning properly. An appropriate size bag, face mask and airway should be available at the child’s bedside. Establish and set up oxygen therapy for post extubation. Ensure all necessary equipment is available including intubation equipment. (22, 23).

Secure supplementary oxygen therapy via nasal cannula as clinically indicated. Minimal handling of patient initially.

Other rare medical problems associated with extubation.Possible causes of inability to remove the tracheal tube are failure to deflate the cuff caused by a damaged pilot tube, trauma to the larynx, cuff herniation, adhesion to the tracheal wall and surgical fixation of the tube to adjacent structures. Sequelae can vary from aspiration to fatal haemorrhage if undue force is applied. The problem is usually solved by puncturing the cuff transtracheally or using a needle inserted into the stump of the pilot tube; rotation and traction of the tube; using a fibreoptic scope for diagnosis; and surgical removal of tethering sutures. The cardio vascular response of tracheal extubation is

associated with a 10–30% increase in arterial pressure and heart rate lasting 5–15 min. Patients with coronary artery disease experience a 40–50% decrease in ejection fraction. The response may be attenuated by pharmacological interventions including: esmolol (1.5 mg kg21 i.v. 2–5 min before extubation), glyceryltrinitrate, magnesium, propofol infusion, remifentanil/alfentanil infusion, i.v.lidocaine (1 mg kg21 over 2 min), topical lidocaine 10% and perioperative oral nimodipine with labetalol. Alternatively, tracheal intubation can be converted to a laryngeal mask before extubation (22).

Figure 6. Laryngeal mask

Diagnosis of PES

Sridor is audible symptom produced by rapid, turbulent flow of air by a narrowed segment of the respiratory tract. Inspiratory stridor indicates obstruction above the thoracic inlet, whereas the expiratory and biphasic stridor are associated with narrowing below the larynx. Quiet respirations maximize gas exchange butrapid flow inspiration such as with vigorous crying considerably accentuates the degree of obstruction and stridor. The young child’s airway lacks full cartilaginous support and is, therefore, pliable and capable of changing the lumen diameter and cross-sectional area for gas flow. During rapid inspiration (or accelerated gas flow) through anatomically narrowed or partially obstructed orifice, the intraluminal pressure of the extrathoracic airway becomes less than athmospheric. The transluminar pressure gradient then tends to narrow the lumen further,

augmenting the obstruction, and increasing the inspiratory stridor. During expiration, however, the extrathoracic intraluminal pressure becomes positive with respect to the athmospheric pressure, causing the lumen to dilate and lessening the obstruction (24).

PES may occur within hours of extubation. The most obvious clinical symptom is sound breathing. Barking, brassy cough may be present as well. All these symptoms reflect varying degree of respiratory obstruction. Dyspnea, tachypnea, tachycardia and suprasternal retraction are common and may often be evident, too (20).

The novel technique proposed to evaluate the possibility of PES is the airway ultrasound. Using ultrasound helps to identify and estimate the width of the air leak around the ET. The studies have demonstrated a significant decrease in LACWD (Laryngeal Airway Column Width

Difference) in children who developed PES compared to those who did not develop PES. LACWD was defined as the difference between width of air column passed through the vocal cord obtained by ultrasound with inflated and deflated balloon cuff. The readings were recorded for three times, and the average was taken. The change in air column width when the ET cuff was inflated and deflated reflected the change of air leak around the endotracheal tube. So, this width difference will be expected to decrease when air leak decreases reflecting presence of laryngeal edema and

predicting the development of PES (25).

Prevention of PES

First step in prevention of PES is reducing the factors affecting PES and correcting them. Using correct size ET tube. Selecting an ETT for the pediatrics patient requires the anesthesiologist to concider several issues. The tube must be sufficiently large to permit spontaneous or controlled ventilation but not so large as to damage the trachea. It must also seal the trachea against aspiration this can be accomplished either by inflating a cuff or by selecting a tube whose external diameter nearly fills the trachea. In addition, the tube must be composed of materials that do not elicit an inflammatory response. The increased resistance of a small ET tubes typically leads the anaesthesiologist/NICU physicians to select the largest tube that will enter the patient’s trachea. Additional reasons for selecting a large tube include the lesser likelihood of secretions plugging a larger tube, the ability to pass a larger suction catheter should suctioning be necessary and the lesser likelihood that a large tube will permit aspiration of foreign material into the lung. However, placing a large ET tube may damage the trachea by applying excessive pressure to the tracheal mucosa. Therefore, the anaesthesiologist/NICU staff must use the tube that is sufficiently, but not too large.

• Here are formulas helping to select the correct ET tube size in children (16): Tube size (mmID) children younger than 6 years =Age (years) +3.75 3

Tube size (mmID) for children older than 6 years = Age (years) + 4.5 4 For practical reason recommended a single formula based on age Tube size (mmID) = Age (years )+18

4

However, none of these formulas are indicative for newborn patients. ET tube size for the newborns (term and preterm) can be selected according to the following recommendation (16) (Table 2).

The others recommend following ET tube sizes in neonates, infants and children (Table 3) (15).

Yet, one of the most recent recommendations for the size and depth of ET tubes in infants and children of various ages is following (Table 4) (12).

• Monitoring cuff pressure (keep below 20 cm H2O, but not deflated as ridges cause trauma). Cuff leak test to identify upper airway leak is helpful in preventing stridor (26). Alternatively, an audible leak or quantitative assessment of cuff leak volume may be used to predict risk of PES. Children who have an absent air leak at 25 cm of H2O have a 2.8 time greater incidence of adverse respiratory events (laryngospasm, upper airway obstruction and oedema).

• Preventing friction of tube in trachea: proper fixation and give good position to the child, use of sedation like midazolam. If we are not giving proper fixation self extubation may happen. Reintubation may be required. This can lead to PES and other complications.

• Avoiding intubation in the presence of upper respiratory tract infection (16).

• Avoid forceful suctioning: forceful suctioning may cause injury to the airway and lead to inflammation to the larynx and swelling (3, 4).

• Use of prophylactic steroids should reduce the re-intubation rate in neonates (3, 4, 26, 27). • Using dexamethasone dose ranged from 0.25 – 0.5 mg/kg intravenously given 6 h

beforeextubation (3, 4, 26)

• Using corticosteroids reducing the incidence of reintubation and airway obstruction following prolonged intubation for more than 24 h in children.

• Reduce the time of mechanical ventilation and tracheal intubation. Prolonged intubation more than 72 h is found to be a risk factor for failed extubation and reintubation.

• Use of microcufftracheal tubes (TT) for neonates and less than 3 kg babies (28).

• Reduce intubation attempts – prepare carefully for the intubation procedure. Before intubating a baby give the correct position of the child: blanket bellow the shoulders and neutral head position, to overcome the influence of the great occiput of the children (Figure 7).

Figure 7. Proper position of the child before intubation of trachea (blanket under the shoulders and neutral head position)

Table 2. Recommendation (no 1) for the endotracheal tube type and size (internal diameter) in newborns and children (16)

Patient age Size (internal diameter, mm) type Premature neonate Full-term neonate 3 month-1 year 2.0-3.0 3.0-3.5 4.0 Uncuffed Uncuffed Cuffed or uncuffed

2 years 4 years 6 years 8 years 10 years 12 years 4.5 5.0 5.5 6.0 6.5 7.0 Cuffed or uncuffed Cuffed or uncuffed Cuffed Cuffed Cuffed Cuffed

Table 3. Recommendation (no 2) for the endotracheal tube type and size (internal diameter) in newborns and children (15)

<2kg 2.5-mm ID uncuffed tube

2.0 – 3.5 kg 3.0- mm ID uncuffed tube

>3.5kg 3.5- mm ID uncuffed tube

At 6 mo 4.0 –mm ID uncuffed tube

At 1 yr 4.5 mm ID uncuffed tube

>2 yr of age Use the formula (age/4)+4.5 mm ID >8yr of age Use a cuffed tube with no leak

Table 4.Recommendation (no 3) for the endotracheal (ET) tubetype and size (internal diameter) in newborns and children (12)

Age of the patient Size of internal diameter of the endotracheal tube Preterm neonate 2.5 Term neonate 3.0 6 months 3.0-3.5 1-2 years 4.0 3-4 years 4.5 5-6 years 5.0 10 years 6.0

IMPORTANT NOTE: to maintain the same external diameter, the size of the cuffed ET tube is about 0.5 smaller than the uncuffed tube. For example, the 4-year old who requires 4.5 mm

Treatment and management of PES

• Using dexamethasone and its dose ranged from 0.25 – 0.5mg/kg(intravenous) given 6h before extubation and every 6h for up to 24 h after extubation .

• Adrenaline nebulization is the most effective treatment in neonates (8,26, 29,30). While giving nebulization correct position to the newborn or child must be given (sitting or head up position) (Figure 8).

• Adrenaline nebulizer - 0.4 ml/kg per dose (maximally 5 ml) of 1:1000 Adrenaline dilute into 2-4 ml of 0.9 % Sodium chloride via facemask. (4, 31).

uncuffed ET tube should be intubated with a 4.0 mm cuffed ET tube. Because of the need to decrease the size, the benefit of the cuff must be balanced against the decrease in cross sectional area of the smaller tube. It should be noted, that the smaller the ET tube number is used, the greater

the impact of cuffed tube versus uncuffed, e.g. the “insult” of decrease in cross sectional are of 3.0 mm cuffed ET tube versus 3.5 mm uncuffed tube is greater than the “insult” of 5.0 mm cuffed tube

Figure 8. The correct position of the child for the inhalational treatment for postextubation stridor

• Nebulized corticosteroids have a good effect, faster onset, and less systemic absorption compared to intravenous route. Their use in the treatment of croup/stridor has previously been shown to be as effective as dexamethasone in decreasing croup/stridor scores and shortening length of hospital stay. The histological findings of PES are similar to that of croup characterized by mucosal inflammation, ulceration, and edema. Studies showed no difference in incidence of PES comparing between treatment with nebulized L-epinephrine and 1,000 μg of budesonide in children. Fluticasone propionate is a commonly used inhaled corticosteroid in children. It exhibits anti-inflammatory effect twice as high as budesonides in the same equivalent dose with less systemic adverse effects (30) .

• Budesonide nebuliser via facemask and oxygen (O2) – 1 mg for two doses 30 minutes apart and then a 12h until clinical improvement.

• In addition, inspiratory stridor (above the thoracic inlet) can be effectively minimized during spontaneous mask ventilation by maintaining constant positive airway pressure within the breathing system, and reversing the upper airway pressure gradient (24).

• Reintubation may be necessary in severe cases, tracheostomy is rarely needed.

5.ORGANISATION AND METHODOLOGY OF THE

RESEARCH

This retrospective study was performed in Lithuanian University of Health Sciences, Kaunas, Lithuania from 2018 – 2019. The study was approved by the Bioethical Research Center Nr.BEC – JSP(M) 192 (Annex 1)

Case files of the neonates and ex-preterm infants who had undergone general surgery with tracheal intubation and mechanical ventilation after surgery over the period of 2008 – 2010 years were identified and reviewed. The data on patients’ demographics (age, gestation, weight), physical status of the patients before surgery according to the classification by the American Society of Anesthesiology (ASA class), type of surgery, the need of tracheal intubation before surgery, duration of mechanical ventilation after surgery and the incidence of documented symptom “postextubation stridor” were collected. Case files with a documented “postextubation stridor” were additionally analyzed and data, which are known to be associated with the development of PES: ET tube size, method of sedation for tracheal intubation, experience of staff (NICU or anesthesiology)

performing tracheal intubation. In addition, data about treatment measures initiated after evidence of PES, duration of administered treatment and outcome of PES were collected. The used ET tube size was then compared to the two existing recommendations per patient age (Table 5) (16) and Table 6 (12).

All data were collected and stored in a computer-based data file.

Table 5. Recommended endotracheal (ET) tube size per infant age by Fisher D.M (1994year) (16)

Infant age ET size (internal diameter, mm) type Premature neonate Fulltermneonate3month-1 year 2.0-3.0 3.0-3.5 4.0 Uncuffed Uncuffed Cuffed or uncuffed

Table 6. Recommended endotracheal (ET) tube size per infant age by Brett C (2007 year) (12) Infant age ET size (internal diameter,

mm) type Premature neonate Full-term neonate 6 month 2.5 3.0 3.0-3.5 Uncuffed Unuffed uncuffed

Statistical analysis

Continuous variables were checked for the normality of distribution with skewness and kurtosis test. As the continuous variables (age, gestational age, weight and the duration of tracheal intubation after surgery) were distributed abnormally, results are presented as median (min-max). A Mann-Whitney test was used for the comparison of abnormally distributed demographic variables (age, gestational age, weight) and the duration of tracheal intubation after surgery between groups of patients with and without PES. Nominal variables (prematurity, gender, ASA class, type of

surgery, number of patients with tracheal intubation before surgery) are presented as number of cases (%) and compared with a Chi-square test between groups of patients with and without PES. A p-value less than 0.05 was considered statistically significant. All statistical analyses were performed with STATA 7 software.

6.RESULTS

Case file selection, demographic and clinical variables of the analyzed

patients

Eighty (male 44/female 36) case files were reviewed. The flowchart of the case files selection, review and analysis is shown in Figure 9.

Figure 9.The flowchart of the case files selection and review process

The demographic and clinical variables of the 80 patients studied are shown in Table 7. Table 7. Demographic and clinical variables of the 80 studied patients

Age at the day of operation (days) 6 (1-72)

Gestational age (weeks) 38 (23-42)

Premature/term (n or %) 33/47 or 41.25%/58.75%

Gender male/female (n or %) 44/36 or 55%/45%

ASA class 1/2/3/4/5 (n or %) 1/22/33/20/4 or

1.25%/27.5%/41.25%/25%/5%

Patients with tracheal intubation before surgery (n or %)

19 (23.75%)

Duration of tracheal intubation after surgery (h)

38 (0-729)

Type of surgery of the studied patients is shown in Figure 10.

Figure 10.Type of surgery of the 80 patients studied. Data are expressed in %.

Tracheal extubation and the incidence of PES

Sixty-six patients (82.5%) were extubated within 30 (0-384) h after surgery, while 14 (17.5%) had never been extubated. The incidence of extubation was significantly associated with the gestation of the patients: 33.3% of premature infants versus only 6.4% of full-term neonates had never been extubated, p=0.002.

22,5

16,25

12,5

11,25

11,25

8,75

6,25

2,5 3,75

5

Prievarčio stenozė/ Ladd sindromas Storosios žarnos apsigimimai Teratoma Stemplės pažeidimai Skrandžio pažeidimai/ gastrošyzė kita

PES was identified in 10/66 (15.2%) of extubated patients.

ET tube size and the method used for the intubation of trachea in patients

with PES

ET tube size in patients with PES ranged from 3.0 to 4.5. In one patient cuffed ET was used, in 9 patients uncuffed ETs were used. The tracheas of 2 out of 10 patients with PES were intubated with larger ET than recommended according recommendation by Fisher D.M..(Figure 11). However, according to the recommendationby Brett C., even 8 out of 10 patients were intubated with larger ET than recommended (Figure 12). Furthermore, 1 out of 10 patients was intubated with ET no 4.5 which is recommended only by age of over a year, regardless of recommendation used. Tracheal intubation was performed by NICU physicians in 9 out of 10 cases under sedation with morphine or diazepam and muscle relaxation with a short acting muscle relaxant mivacurium. Only in 1 case the intubation of trachea was performed by anesthesiologist under general anesthesia.

Figure 11. The proportion of patients who were intubated with endotracheal tube size compliant with the recommendation by Fisher DM (1994 year)

80%

20% _{complies to recommendation}

does not comply to recommendation

Figure 12. The proportion of patients who were intubated with endotracheal tube size compliant with the recommendation by Brett C (2007 year)

Table 8. Comparison of demographic variables and duration of mechanical ventilation between patients with and without postextubation stridor (PES)

Variable Patients without PES

N=56

Patients with PES N=10

P-value

Age at the day of operation (days)

5 (1-72) 11.5 (1-24) 0.672

Gender male/female (n or %) 30/26 or 53.6%/46.4% 5/5 or 50%/50% 0.835 Gestational age (weeks) 38 (23-42) 38.5 (36-40) 0.282 Premature/term (n or %) 22/34 or 39.3%/60.7% 3/7 or 30%/70% 0.577

Weight (g) 2700 (700-5080) 3340 (2314-3765) 0.042

Duration of tracheal intubation after surgery (h)

38 (0-384) 24 (0-48) 0.098

20%

80%

complies to recommendation

does not comply to recommendation

Treatment strategies of PES and outcome

Five patients (5/66 (7.6%)) were treated with the inhalation of adrenalin in normal saline, the rest were treated with the inhalation of normal saline.

Additional oxygen was required in 3/10 cases.

The duration of treatment ranged from 1 to 24 h and there were no long term consequences.

Comparison of groups of patients with and without PES

Except for the weight of the patients, there was no difference in demographic variables and duration of mechanical ventilation between patients with and without PES (Table 8).

7.DISCUSSION OF THE RESULTS

PES was identified in 10/66 (15.2%) of extubated patients. Variable incidence of PES is reported in literature. Some studies report the incidence rate of 1.6 – 6% in infants and children. Another study says that post-extubation stridor occurs after 2–16% of extubations in the ICU (18).Other studies provide the incidence rate between 3.5 – 30.2% (3, 4, 6). Thus the incidence found in our study matches the incidence reported in literature.

ET tube size is the established risk factor for PES. The majority of the studied patients with PES were intubated with the ET appropriate for age, when compared to the older recommendation (16). On the contrary, though, the majority of our patients were intubated with a larger than recommended according to the age of the patient by the newer recommendation (12). Asnot a single recommendation exists, regarding the recommended size of ET in neonates and infants, we cannot confirm nor deny that the etiology of PES in our patients was related to ET tube size.

The majority of our patients with PES were intubated by NICU staff under light sedation and muscle relaxation and only 1 patient was intubated by anesthesiologist under general anesthesia. Adequate sedation and muscle relaxation are associated with less traumatic intubation (3, 9). However, the level of sedation during intubation was not objectively assessed during intubation of the studied patients. Intubation is also less traumatic when experienced physicians in contrast to inexperienced ones manage the intubation. Further prospective studies, focused on here found

possible risk factors are required in order to clarify the causes of PES between our neonates undergoing surgery.

Half of our patients with PES were treated with the inhalation of adrenaline in normal saline. Literature review proves that adrenalin is the most effective medicine for treating PES in neonates and children and some of the literature review says that adrenalin and dexamethasone will help to reduce the incidence of PES (4, 11, 32). We did not analyse the case files of the patients, who did not experience PES, therefore we do not know if steroids were used to prevent PES in our patients who did not experience PES. Half of our patients with PES received the inhalation of normal saline only. This may mean that the stridor was mild and the decision not to administer adrenaline was taken. This is support by the fact that only 3/10 patients required additional oxygen after extubation.

In contrast to the data described in literature, we found that PES was experienced by larger patients compared to smaller ones. The incidence was also not different in term and preterm neonates. Our result may be flawed by the high mortality rate (never extubated) of premature infants (33.3%) within our patient group studied. Table 8.also indicates that proportion of preterm and term neonates was comparable in both groups (with PES and without PES). Therefore, probably, other than demographic factors were related to PES between our patients studied. A randomized prospective multicentre double-blind trial of 700 patients showed that the incidence of laryngotracheal oedema leading to upper airway narrowing was higher in female patients, especially those intubated for 36 h (18). Other risk factors for PES include mobile and large tracheal tubes, excess cuff pressure, tracheal infection, patients fighting the ventilator, aggressive tracheal suctioning and the presence of a nasogastric tube (33, 34, 35).

8.CONCLUSIONS

1.Postextubation stridor is a frequent complication in neonates and ex-preterm infants after surgery (15.2%).

2. Treatment of postextubation stridor depended on the severity of stridor and consisted of inhalation of normal saline or adrenaline in normal saline. Inhalation of adrenaline was administered in half of the cases.

3. Based on this retrospective analysis no definitive causes of postextubation stridor could be identified. However, smaller endotratracheal tube sizes should be considered. Studies, focusing on

possible risk factors are required in order to minimize the incidence of postextubation stridor in neonates and ex-preterm infants after surgery.

9. PRACTICAL RECOMMENDATIONS TO PREVENT PES IN

NEONATES AND EX-PRETERM INFANTS FOR NURSES

• Adequate sedation and relaxation before tracheal intubation • Diminish intubation attempts (experienced staff)

• Fix ET tube properly to prevent accidental extubation • Do not use full strength on suctioning the secretions • Proper positioning to the baby / child

• Strict aseptic technique

• Use of ultrasound to detect patients at risk for PES • Use prophylactic steroids before extubation

Recommendation for parents to take care the child in home

• After surgery baby’s or children may cried more because of pain so be careful to handle the child and must give pain killers

•

:

(approximately 37°C) when fully clothed, in an open cot

• Teach the parents to how to give medications, nutrition supplements and timings • Advise the mother to give breast feed or bottle feed on proper time

• Advise parents to the home also follow aseptic technique while handling the baby • Follow up health check-up and vaccination

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Lietuvosmokslų akademija; 2012; 19 (3):303.

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3. den Hollander D, Muckart D.Post-extubation stridor in children. A case report and review of the literature. South. Afr. j. crit. Care. 2009; 25 (1): 20-26.

4. East Midlands Congenital Heart Centre. Post Extubation Stridor. Version:3 Trust Ref: C119/2016

5. Chiwane SS, Sarnaik AP. Postextubation Stridor: What's All That Beyond the Noise. Pediatr crit care med. 2017;18 (5): 492-494. doi: 10.1097/PCC.0000000000001143.

6. Nascimento MS, Prado C, Troster EJ, Valerio N, Alith MB, de Almeida JFL. Risk factors for post-extubation stridor in children: the role of orotracheal cannula. Einstein. 2015; 13 (2) :226-31.doi: 10.1590/S1679-45082015AO3255.

7. Dorland‘s pocket medical dictionary. Abridged from Dorland‘s illustrated medicaldictionary. Philadelphia: W.B. Saunders Company, 1989, p. 564.

8. Veldhoen ES, Smulders CA, KappenTH,Calis JC, van Woensel J, Raymakers-Janssen P, et al. Post-extubation stridor in Respiratory Syncytial Virus bronchiolitis: Is there a role for prophylactic dexamethasone? PLoS ONE. 2017; 12 (2) : e0172096. doi:10.1371/journal. pone.0172096.

9. NatsukoOhsima, Fumimasa Amaya, ShunsukeYamakita, Yoshinobu Nakayama, Hideya Kato, YumiMuranishi,ToshiakiNumajiri and TeijiSawa Difficult tracheal intubation and postextubation airway stenosis in an 11-month old patient with unrecognized subglottic stenosis: a case report Ohsima et al. JA Clinical Reports. 2017; 3:10.doi 10.1186/s40981- 017-0079-4.

of post-extubation stridor in neonates, children and adults. Cochrane Database of SystematicReviews.2009; 3. Art. NoCD001000.doi:10.1002/14651858.CD001000.pub3.

11. Malhotra D, Curgoo S, Shora A, Farooqi A, Qazi M, Dar B, Qazi S. Role of dexamethasone in prevention of post extubation upper airway complications in paediatric patients in

anintensive care unit. The Internet Journal of Anesthesiology. 2008; 19 (1): 1-4.

12. Brett C. Pediatrics. In: Stoelting R and Miller R, editors. Basics of Anesthesia. Philadelphia - Churchill Livingstone; 2007, p. 506-508.

13. Anesthesia for thoracic pediatric surgery. In: Benumof JL, editor. Anesthesia for Thoracic surgery. Philadelphia London Toronto Montreal Sydney Tokyo: W.B. Saunders Company; 1987, p. 411-412.

14. Respiratory system. In: Steward DJ, editor. Manual of pediatricanesthesia. New York Edinburgh London Melbourne: Churchill Livingstone; 1990, p. 13-14.

15. The airway. In: Bloch EC, editor. Pediatricanesthesia: a pocket companion.Boston London Oxford Singapore Sydney Toronto Wellington: Butterworth-Heinemann; 1994, p. 60-61. 16. Fisher D.M. Anesthesia equipment for pediatrics. In: Gregory G.A, editor.

Pediatricanesthesia. New York, Edinburgh, London, Melbourne, Tokyo: Churchill Livingstone; 1994, p. 197-216.

17. Pfleger A, Eber E. Assessment and causes of stridor. Paediatric Respiratory Reviews. 2016;18 : 64–72.

18. Wittekamp BH, van Mook WN, Tjan DH, Zwaveling JH, Bergmans DC. Post extubation laryngeal edema and extubation failure in critically ill patients. Critical care. 2009; 13 (6):233.

19. Sinha A, Jayashree M, Singhi S. Aerosolized L epinephrine versus budesonide for postextubation stridor: a randomized controlled trial. Indian Pediatr. 2010; 47 (4):317–322.

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Otorhinolaryngol. 2019; 27 (121) :64-67. doi: 10.1016/j.ijporl.2019.02.044.

22. Karmarkar S, Varshney S. Tracheal extubation: continuing education in anaesthesia. Critical Care & Pain. 2008; 8 (6).

23. Tieman E.Guideline for nurses on assisting with intubation and extubation of infants and children. Our Lady’s Children’s Hospital, Crumlin. Reference Number: NAIEIC-05-2016-ETRC-V3 Version. 2016; 3:2-33.

24. France NK. Anesthesia for pediatric ENT. In: Gregory GA, editor. Pediatricanesthesia. New York Edinburgh London, and Melbourne: Churchill Livingstone; 1983, p. 825-825. 25. Amrousy DE, Elkashlan M, Elshmaa N, Ragab A. Ultrasound-Guided Laryngeal Air Column

Width Difference as a New Predictor for PostextubationStridor in Children. Crit Care Med.2018; 46:e496–e501. doi:10.1097/CCM.0000000000003068

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Emerg Med. 2016; 2:013: 1-4.

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29. da Silva PS, Fonseca MC, Iglesias SB, Junior EL, de Aguiar VE, de Carvalho WB. Nebulized 0.5, 2.5 and 5 ml L-epinephrine for post-extubation stridor in children: a

prospective, randomized, double-blind clinical trial. Intensive Care Med. 2012; 38(2) :286-293. doi: 10.1007/s00134-011-2408-9.

30. Prasertsan P, Nakju D, Lertbunrian R, Chantra M, Anantasit N. Nebulized Fluticasone for Preventing Postextubation Stridor in Intubated Children: A Randomized, Double-Blind Placebo-Controlled Trial. PediatrCritCare Med.2017; 18 (5):201–e206.

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11.

PUBLICATION

1. Jose SM, Rugyte D. Post extubation stridor (PES) in surgical neonates and ex-preterm infants. In: 2019 Nurses: A voice to lead - health for all, 2019 May 7; Kaunas (Lithuania). Abstract is accepted for oral presentation.

SONA MARIA JOSE

Post Extubation Stridor (PES) in Surgical Neonates and Ex-Preterm Infants

Poekstubacinio stridoro (PES) pasireiškimas tarp operuotų naujagimių ir prieš laiką gimusių kūdikių

Prof. Dr. Danguole Rugyte , Dr. Laura Lukošiene

Key words : Extubation, Endotracheal, Airway Obstruction, neonates, respiratory system Summary

In this retrospective work, the appearance of post-extubation stridor after general neonatal and infant surgery is analyzed. Frequency and risk factors such as endotracheal tube size are reported. Describes tailored treatment and outcomes. There is also a comprehensive review of literature on the specificity of the newborn and infant's respiratory tract, leading to the development of post-extubation stridor, possible other risk factors, post-extubation stridor diagnosis and treatment. Practical recommendations are given to medical personnel about post-extubation stridor prophylaxis and precautionary measures.

Santrauka

Šiame retrospektiniame darbe analizuojamas poekstubacinio stridoro pasireiškimas po bendrųjų naujagimių ir kūdikių operacijų. Pateikiamas dažnis ir analizuojami rizikos faktoriai, tokie kaip endotrachėjinio vamzdelio dydis. Aprašomas pritaikytas gydymas ir išeitys. Taip pat pateikiama plati literatūros apžvalga apie naujagimių ir kųdikių kvėpavimo takų specifiką, lemiančią poekstubacinio stridoro išsivystymą, galimus kitus rizikos

veiksnius, poekstubacinio stridoro diagnostiką ir gydymą. Pateikiamos praktinės

rekomendacijos medicinos personalui apie poekstubacinio stridoro profilaktiką ir atsargumo priemones.